//! The JSON API (hub spec §12.1) under `/api/v1`: bearer tokens, RFC 7807
//! problems, the same shapes as `oxy --json` where one exists. Reads need
//! `repo:read` (anonymous for public repositories); writes the scope named
//! on each handler.

use crate::auth::{self, Access, Role};
use crate::db::{self, accounts::Account};
use crate::repos::{view, RepoError, RepoName};
use crate::Shared;
use axum::extract::{Path, Query, State};
use axum::http::{HeaderMap, StatusCode};
use axum::response::{IntoResponse, Response};
use axum::routing::{get, post};
use axum::{Json, Router};
use hub_api::*;
use serde::Deserialize;

mod backups;
pub mod device;
mod drops;
mod images;
mod projects;
mod reports;

/// Any other path under `/api/v1`: a problem document, not the site's page.
/// `GET /api/v1/version`: the hub's version and build, and the Oxygen and
/// OxygenFlow library versions it is built on.
async fn version() -> Json<serde_json::Value> {
    Json(crate::web::home::versions())
}

async fn no_route() -> ApiError {
    ApiError(StatusCode::NOT_FOUND, "no such API route".into())
}

/// A known route asked with a method it does not take: a problem body
/// rather than axum's empty 405 (oxygenhub#115).
async fn wrong_method(method: axum::http::Method, uri: axum::http::Uri) -> ApiError {
    ApiError(StatusCode::METHOD_NOT_ALLOWED, format!("{} is an API route, but not for {method}", uri.path()))
}

/// The API, with release assets up to `asset_limit` bytes (the web form's
/// limit too; axum's default of 2 MiB refused ordinary builds).
pub fn router(asset_limit: usize) -> Router<Shared> {
    Router::new()
        .fallback(no_route)
        .route("/keyless/certify", post(crate::keyless::certify))
        .route("/agents/grants", get(crate::keyless::grants_list).post(crate::keyless::grants_create))
        .route(
            "/repos/{owner}/{name}/terraform/state/{state}",
            axum::routing::any(crate::terraform::state)
                .layer(axum::extract::DefaultBodyLimit::max(crate::terraform::MAX_STATE_BYTES + 4096)),
        )
        .route("/repos/{owner}/{name}/terraform/state/{state}/versions", axum::routing::get(crate::terraform::versions))
        .route("/repos/{owner}/{name}/terraform/state/{state}/versions/{id}", axum::routing::get(crate::terraform::version))
        .route(
            "/repos/{owner}/{name}/terraform/state/{state}/versions/{id}/restore",
            axum::routing::post(crate::terraform::restore_version),
        )
        .route("/agents/grants/{id}", axum::routing::delete(crate::keyless::grants_revoke))
        .route("/flow/claim", post(crate::flow::claim))
        .route("/flow/runners/register", post(crate::flow::register))
        .route("/flow/runners/heartbeat", post(crate::flow::heartbeat))
        .route("/flow/runner/update", get(crate::flow::runner_update).post(crate::flow::report_update))
        .route("/flow/images/missing", post(images::missing).layer(axum::extract::DefaultBodyLimit::max(images::MAX_ASK_BYTES)))
        .route("/flow/swarm/announce", post(crate::swarm::announce))
        .route("/flow/images/chunks/{hash}", axum::routing::put(images::put_chunk).get(images::get_chunk))
        .route(
            "/flow/images/{hash}",
            axum::routing::put(images::put_manifest).get(images::get_manifest).layer(axum::extract::DefaultBodyLimit::max(64 << 20)),
        )
        .route("/flow/jobs/{id}/log", post(crate::flow::log))
        .route("/flow/jobs/{id}/finish", post(crate::flow::finish))
        .route("/flow/jobs/{id}/decline", post(crate::flow::decline))
        .route("/flow/jobs/{id}/release", post(crate::flow::release))
        .route(
            "/flow/jobs/{id}/checkpoint",
            post(crate::flow::save_checkpoint)
                .get(crate::flow::checkpoint)
                .layer(axum::extract::DefaultBodyLimit::max(crate::flow::MAX_ARTIFACT_BYTES + (1 << 20))),
        )
        .route(
            "/flow/jobs/{id}/artifacts/{name}",
            post(crate::flow::artifact).layer(axum::extract::DefaultBodyLimit::max(crate::flow::MAX_ARTIFACT_BYTES + (1 << 20))),
        )
        .route("/flow/jobs/{id}/inputs/{index}", get(crate::flow::input))
        .route(
            "/flow/jobs/{id}/reports/{name}/files",
            post(crate::flow::report_file).layer(axum::extract::DefaultBodyLimit::max(crate::flow::MAX_ARTIFACT_BYTES + (1 << 20))),
        )
        .route("/projects/{owner}", get(projects::list).post(projects::create))
        .route("/projects/{owner}/{number}", get(projects::board).patch(projects::edit))
        .route("/projects/{owner}/{number}/cards", get(projects::cards).post(projects::add_card))
        .route("/projects/{owner}/{number}/cards/move", post(projects::move_cards))
        .route("/projects/{owner}/{number}/cards/archive", post(projects::archive_cards))
        .route("/projects/{owner}/{number}/cards/{id}/restore", post(projects::restore_card))
        .route("/projects/{owner}/{number}/cards/{id}", axum::routing::patch(projects::move_card).delete(projects::remove_card))
        .route("/device/code", post(device::code).delete(device::cancel))
        .route("/device/token", post(device::token))
        .route("/runners", get(runners))
        .route("/runners/queue", get(runner_queue))
        .route("/runners/{id}/jobs", get(runner_jobs))
        .route("/user", get(me))
        .route("/user/repos", get(user_repos))
        .route("/user/orgs", get(user_orgs))
        .route("/user/proposals", get(user_proposals))
        .route("/user/runner-token", post(user_runner_token))
        .route("/user/token", axum::routing::delete(revoke_own_token))
        .route("/version", get(version))
        .route("/notifications", get(notifications))
        .route("/notifications/read", post(notifications_read_all))
        .route("/notifications/{id}/read", post(notification_read))
        .route("/users/{name}", get(user))
        .route("/users/{name}/drops", get(drops::of_user))
        .route("/drops", get(drops::mine).post(drops::create))
        .route("/drops/{id}", get(drops::view).patch(drops::edit).delete(drops::delete))
        .route("/orgs/{name}", get(org))
        .route("/search", get(search))
        .route("/repos", get(list_repos).post(create_repo))
        .route("/repos/{owner}/{name}", get(get_repo))
        .route("/repos/{owner}/{name}/bookmarks", get(bookmarks))
        .route("/repos/{owner}/{name}/tags", get(tags).post(create_tag))
        .route("/repos/{owner}/{name}/tags/{tag}", axum::routing::delete(withdraw_tag))
        .route("/repos/{owner}/{name}/consumers", get(consumers))
        .route("/repos/{owner}/{name}/diffusion", get(diffusion).put(set_diffusion))
        .route("/repos/{owner}/{name}/backup", axum::routing::put(set_backup))
        .route("/user/backups", get(backups::user_get).put(backups::user_put))
        .route("/user/backups/test", post(backups::user_test))
        .route("/user/backups/run", post(backups::user_run))
        .route("/user/backups/runs", get(backups::user_runs))
        .route("/orgs/{name}/backups", get(backups::org_get).put(backups::org_put))
        .route("/orgs/{name}/backups/test", post(backups::org_test))
        .route("/orgs/{name}/backups/run", post(backups::org_run))
        .route("/orgs/{name}/backups/runs", get(backups::org_runs))
        .route("/repos/{owner}/{name}/history/{r}", get(history))
        .route("/repos/{owner}/{name}/changes/{hash}", get(change))
        .route("/repos/{owner}/{name}/tree/{r}", get(tree_root))
        .route("/repos/{owner}/{name}/tree/{r}/{*path}", get(tree))
        .route("/repos/{owner}/{name}/file/{r}/{*path}", get(file))
        .route("/repos/{owner}/{name}/blame/{r}/{*path}", get(blame))
        .route("/repos/{owner}/{name}/conflicts", get(conflicts))
        .route("/repos/{owner}/{name}/trust", get(trust))
        .route("/repos/{owner}/{name}/releases/trust/{*tag}", get(release_trust))
        .route("/repos/{owner}/{name}/pushes", get(pushes))
        .route("/repos/{owner}/{name}/proposals", get(proposals).post(create_proposal))
        .route("/repos/{owner}/{name}/proposals/{number}", get(proposal).patch(edit_proposal))
        .route("/repos/{owner}/{name}/proposals/{number}/land", post(land_proposal))
        .route("/repos/{owner}/{name}/proposals/{number}/auto-land", post(auto_land_on).delete(auto_land_off))
        .route("/repos/{owner}/{name}/proposals/{number}/comments", get(proposal_comments).post(proposal_comment))
        .route("/repos/{owner}/{name}/proposals/{number}/reviews", get(proposal_reviews).post(proposal_review))
        .route("/repos/{owner}/{name}/proposals/{number}/reviewers", post(request_reviewers))
        .route("/repos/{owner}/{name}/proposals/{number}/review-requests", post(request_assistant))
        .route("/repos/{owner}/{name}/proposals/{number}/reviewers/{username}", axum::routing::delete(withdraw_reviewer))
        .route("/repos/{owner}/{name}/proposals/{number}/checks", get(proposal_checks))
        .route("/repos/{owner}/{name}/proposals/{number}/files", get(proposal_files))
        .route("/repos/{owner}/{name}/proposals/{number}/content/{side}/{*path}", get(proposal_content))
        .route("/repos/{owner}/{name}/issues", get(issues).post(create_issue))
        .route("/repos/{owner}/{name}/issues/{number}", get(issue).post(issue_state).patch(issue_edit))
        .route("/repos/{owner}/{name}/issues/{number}/comments", get(issue_comments).post(issue_comment))
        .route("/repos/{owner}/{name}/labels", get(labels).post(create_label))
        .route("/repos/{owner}/{name}/labels/{label}", axum::routing::delete(delete_label))
        .route("/repos/{owner}/{name}/milestones", get(milestones).post(create_milestone))
        .route(
            "/repos/{owner}/{name}/coverage",
            get(reports::coverage_list)
                .post(reports::coverage_upload)
                .layer(axum::extract::DefaultBodyLimit::max(crate::coverage::MAX_REPORT + (1 << 20))),
        )
        .route("/repos/{owner}/{name}/coverage/{id}", get(reports::coverage_one))
        .route("/repos/{owner}/{name}/tests", get(reports::tests_list))
        .route("/repos/{owner}/{name}/tests/{id}", get(reports::tests_one))
        .route("/repos/{owner}/{name}/milestones/{title}", axum::routing::patch(edit_milestone))
        .route("/repos/{owner}/{name}/hooks", get(hooks).post(create_hook))
        .route("/repos/{owner}/{name}/assistants", get(repo_assistants).post(repo_assistant_put))
        .route("/repos/{owner}/{name}/assistants/prompt", get(repo_prompt).put(repo_prompt_put))
        .route("/repos/{owner}/{name}/assistants/{assistant}", axum::routing::delete(repo_assistant_delete))
        .route("/orgs/{org}/assistants", get(org_assistants).post(org_assistant_put))
        .route("/orgs/{org}/assistants/prompt", get(org_prompt).put(org_prompt_put))
        .route("/orgs/{org}/assistants/{assistant}", axum::routing::delete(org_assistant_delete))
        .route("/admin/runner-updates", get(runner_updates))
        .route("/admin/runner-updates/settings", axum::routing::put(runner_update_setting))
        .route("/admin/runner-updates/holds/{version}/lift", post(runner_update_lift))
        .route("/admin/assistants", get(site_assistants).post(site_assistant_put))
        .route("/admin/assistants/prompt", get(site_prompt).put(site_prompt_put))
        .route("/admin/assistants/{assistant}", axum::routing::delete(site_assistant_delete))
        .route("/repos/{owner}/{name}/hooks/{id}/delete", post(delete_hook))
        .route("/repos/{owner}/{name}/checks", post(post_check))
        .route("/repos/{owner}/{name}/flow/runs", get(flow_runs).post(start_flow_run))
        .route("/repos/{owner}/{name}/flow/runs/{number}", get(flow_run))
        .route("/repos/{owner}/{name}/flow/runs/{number}/jobs/{job}/log", get(flow_job_log))
        .route("/repos/{owner}/{name}/flow/runs/{number}/rerun", post(rerun_flow_run))
        .route("/repos/{owner}/{name}/flow/runs/{number}/jobs/{job}/rerun", post(rerun_flow_job))
        .route("/repos/{owner}/{name}/flow/runs/{number}/cancel", post(cancel_flow_run))
        .route("/repos/{owner}/{name}/deployments", get(list_deployments))
        .route("/repos/{owner}/{name}/flow/runs/{number}/jobs/{job}/approve", post(approve_flow_job))
        .route("/repos/{owner}/{name}/flow/runs/{number}/jobs/{job}/reject", post(reject_flow_job))
        .route("/repos/{owner}/{name}/flow/runs/{number}/jobs/{job}/approval", get(flow_job_statement))
        .route("/repos/{owner}/{name}/flow/runs/{number}/jobs/{job}/seal", post(seal_flow_job))
        .route("/repos/{owner}/{name}/checks/required", get(required_checks).put(set_required_checks))
        .route("/repos/{owner}/{name}/checks/{state}", get(checks_for_state))
        .route("/repos/{owner}/{name}/releases", get(releases).post(create_release))
        .route("/repos/{owner}/{name}/releases/{tag}", axum::routing::patch(edit_release))
        .route(
            "/repos/{owner}/{name}/releases/{tag}/assets",
            post(upload_asset).layer(axum::extract::DefaultBodyLimit::max(asset_limit + (1 << 20))),
        )
        // Last: it applies to the routes registered before it.
        .method_not_allowed_fallback(wrong_method)
}

async fn releases(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name)): Path<(String, String)>,
) -> Result<Json<Vec<Release>>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (repo, row, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    Ok(Json(crate::web::releases::api_views(&app, &repo, &row).await?))
}

async fn create_release(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name)): Path<(String, String)>,
    Json(body): Json<NewRelease>,
) -> Result<(StatusCode, Json<Release>), ApiError> {
    let c = caller(&app, &headers).await?;
    let me = c.require("repo:write")?.clone();
    let (repo, row, _) = reach(&app, &c, &owner, &name, Access::Write).await?;
    crate::web::releases::create_release(&app, &repo, &row, &me, &body.tag, &body.title, body.notes, body.prerelease)
        .await
        .map_err(|m| ApiError(StatusCode::BAD_REQUEST, m))?;
    let r = crate::web::releases::api_views(&app, &repo, &row)
        .await?
        .into_iter()
        .find(|r| r.tag == body.tag)
        .ok_or_else(|| not_found("no such release"))?;
    Ok((StatusCode::CREATED, Json(r)))
}

/// `PATCH …/releases/{tag}` (oxygenhub#72): change a release's title,
/// notes or prerelease flag, as the release page's Edit does.
async fn edit_release(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, tag)): Path<(String, String, String)>,
    Json(body): Json<ReleaseEdit>,
) -> Result<Json<Release>, ApiError> {
    let c = caller(&app, &headers).await?;
    let me = c.require("repo:write")?.clone();
    let (repo, row, _) = reach(&app, &c, &owner, &name, Access::Write).await?;
    let r = db::releases::get(&app.db, row.id, &tag).await?.ok_or_else(|| not_found("no such release"))?;
    let title = body.title.as_deref().map(str::trim).filter(|t| !t.is_empty()).unwrap_or(&r.title);
    let notes = body.notes.as_deref().map(str::trim).unwrap_or(&r.notes);
    db::releases::edit(&app.db, r.id, title, notes, body.prerelease.unwrap_or(r.prerelease)).await?;
    db::accounts::audit(&app.db, Some(&me), "release.edited", &format!("{owner}/{name}@{tag}"), "").await.ok();
    let r = crate::web::releases::api_views(&app, &repo, &row)
        .await?
        .into_iter()
        .find(|r| r.tag == tag)
        .ok_or_else(|| not_found("no such release"))?;
    Ok(Json(r))
}

#[derive(Deserialize)]
struct AssetQuery {
    name: String,
}

/// `POST …/releases/{tag}/assets?name=file.tar.gz` with the file as the body.
async fn upload_asset(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, tag)): Path<(String, String, String)>,
    Query(q): Query<AssetQuery>,
    body: axum::body::Bytes,
) -> Result<(StatusCode, Json<Release>), ApiError> {
    let c = caller(&app, &headers).await?;
    c.require("repo:write")?;
    let (repo, row, _) = reach(&app, &c, &owner, &name, Access::Write).await?;
    let r = db::releases::get(&app.db, row.id, &tag).await?.ok_or_else(|| not_found("no such release"))?;
    let ct = headers.get(axum::http::header::CONTENT_TYPE).and_then(|v| v.to_str().ok()).unwrap_or("application/octet-stream").to_string();
    crate::web::releases::store_asset(&app, r.id, &q.name, &ct, &body).await.map_err(|m| ApiError(StatusCode::BAD_REQUEST, m))?;
    let r = crate::web::releases::api_views(&app, &repo, &row)
        .await?
        .into_iter()
        .find(|r| r.tag == tag)
        .ok_or_else(|| not_found("no such release"))?;
    Ok((StatusCode::CREATED, Json(r)))
}

pub struct ApiError(pub StatusCode, pub String);

impl IntoResponse for ApiError {
    fn into_response(self) -> Response {
        let body = Problem { status: self.0.as_u16(), title: self.0.canonical_reason().unwrap_or("error").into(), detail: self.1 };
        (self.0, [("content-type", "application/problem+json")], Json(body)).into_response()
    }
}

impl From<RepoError> for ApiError {
    fn from(e: RepoError) -> ApiError {
        match e {
            RepoError::NotFound => not_found("no such repository"),
            RepoError::Oxy(oxy_core::repo::RepoError::Msg(m)) => ApiError(StatusCode::NOT_FOUND, m),
            other => ApiError(StatusCode::INTERNAL_SERVER_ERROR, other.to_string()),
        }
    }
}

impl From<sqlx::Error> for ApiError {
    fn from(e: sqlx::Error) -> ApiError {
        ApiError(StatusCode::INTERNAL_SERVER_ERROR, e.to_string())
    }
}

pub(crate) fn not_found(what: &str) -> ApiError {
    ApiError(StatusCode::NOT_FOUND, what.into())
}

pub(crate) fn forbidden(what: &str) -> ApiError {
    ApiError(StatusCode::FORBIDDEN, what.into())
}

/// The address a request came from: the client's, as the proxy reports
/// it when the hub is behind one (`server.behind_proxy`), else the peer's.
/// Only an address's characters are kept, so it is safe to show.
pub fn client_addr(app: &Shared, headers: &HeaderMap, extensions: &axum::http::Extensions) -> String {
    let from_proxy = || {
        ["cf-connecting-ip", "x-forwarded-for", "x-real-ip"]
            .iter()
            .find_map(|h| headers.get(*h).and_then(|v| v.to_str().ok()).and_then(|v| v.split(',').next()).map(|v| v.trim().to_string()))
    };
    let addr = if app.config.server.behind_proxy {
        from_proxy()
    } else {
        extensions.get::<axum::extract::ConnectInfo<std::net::SocketAddr>>().map(|c| c.0.ip().to_string())
    };
    addr.map(|a| a.chars().filter(|c| c.is_ascii_hexdigit() || matches!(c, '.' | ':')).take(45).collect()).unwrap_or_default()
}

/// `DELETE /api/v1/user/token`: revoke the token this request is made
/// with, as `oxy auth logout` does.
async fn revoke_own_token(State(app): State<Shared>, headers: HeaderMap) -> Result<StatusCode, ApiError> {
    let c = caller(&app, &headers).await?;
    let (Some(account), Some(id)) = (c.account.as_ref(), c.token_id) else {
        return Err(ApiError(StatusCode::UNAUTHORIZED, "revoking needs the personal access token to revoke".into()));
    };
    db::accounts::delete_token(&app.db, account.id, id).await?;
    db::accounts::audit(&app.db, Some(account), "token.revoke", &c.token, "").await.ok();
    Ok(StatusCode::NO_CONTENT)
}

/// Who calls: the account behind a bearer token, with the token's scopes.
pub struct Caller {
    pub account: Option<Account>,
    pub scopes: Vec<String>,
    pub site: bool,
    /// The token's name, for records of what a call did.
    pub token: String,
    /// The personal access token's id, when one is used.
    pub token_id: Option<i64>,
    /// The token is an agent's (oxygenhub#183): what it does says so.
    pub agent: bool,
}

impl Caller {
    fn has(&self, scope: &str) -> bool {
        self.site
            || self.scopes.iter().any(|s| {
                s == scope
                    || (scope == "repo:read" && (s == "repo:write" || s == "repo:admin"))
                    || (scope == "repo:write" && s == "repo:admin")
            })
    }

    fn require(&self, scope: &str) -> Result<&Account, ApiError> {
        // No token is 401, sign in; a token without the scope is 403 (#303).
        let Some(account) = self.account.as_ref() else {
            return Err(ApiError(StatusCode::UNAUTHORIZED, "a personal access token is required: sign in (`oh auth login`)".into()));
        };
        if !self.has(scope) {
            return Err(forbidden(&format!("this token lacks the {scope} scope")));
        }
        Ok(account)
    }
}

pub async fn caller(app: &Shared, headers: &HeaderMap) -> Result<Caller, ApiError> {
    let Some(t) = oxy_server::bearer_token(headers) else {
        return Ok(Caller { account: None, scopes: vec![], site: false, token: String::new(), token_id: None, agent: false });
    };
    if app.config.auth.push_tokens.iter().any(|x| auth::mac_equal(x, t)) {
        let admin = db::accounts::accounts(&app.db).await?.into_iter().find(|a| a.is_admin);
        return Ok(Caller {
            account: admin,
            scopes: vec!["repo:admin".into(), "user:read".into(), "checks:write".into()],
            site: true,
            token: "site token".into(),
            token_id: None,
            agent: false,
        });
    }
    let token = db::accounts::token_by_hash(&app.db, &auth::token_hash(t)).await?;
    match token {
        Some(tok) if !tok.expired(db::now_ms()) => {
            let account = db::accounts::account_by_id(&app.db, tok.account_id).await?.filter(|a| !a.blocked());
            db::accounts::touch_token(&app.db, tok.id).await.ok();
            Ok(Caller {
                account,
                scopes: tok.scope_list().iter().map(|s| s.to_string()).collect(),
                site: false,
                token: tok.name.clone(),
                token_id: Some(tok.id),
                agent: tok.agent,
            })
        }
        _ => Err(ApiError(StatusCode::UNAUTHORIZED, "unknown or expired token".into())),
    }
}

fn repository(app: &Shared, r: &db::repos::RepoRow) -> Repository {
    Repository {
        owner: r.owner.clone(),
        name: r.name.clone(),
        description: r.description.clone(),
        default_bookmark: r.default_bookmark.clone(),
        visibility: r.visibility(),
        created_ms: r.created_ms,
        updated_ms: r.updated_ms,
        clone_url: format!("{}/{}/{}", app.config.base_url(), r.owner, r.name),
    }
}

/// A repository the caller may reach with `access`, else 404.
pub(super) async fn reach(
    app: &Shared,
    c: &Caller,
    owner: &str,
    name: &str,
    access: Access,
) -> Result<(RepoName, db::repos::RepoRow, Role), ApiError> {
    let repo = RepoName::new(owner, name).ok_or_else(|| not_found("no such repository"))?;
    let row = db::repos::get(&app.db, owner, name).await?.ok_or_else(|| not_found("no such repository"))?;
    // A drop is reached through `/drops` only (#279).
    if row.is_drop() {
        return Err(not_found("no such repository"));
    }
    let role = auth::roles::role_for(&app.db, c.account.as_ref(), &row).await?;
    if !auth::roles::allows(role, access) {
        return Err(not_found("no such repository"));
    }
    Ok((repo, row, role.unwrap_or(Role::Read)))
}

fn summary(c: &view::ChangeView) -> ChangeSummary {
    ChangeSummary {
        hash: c.hash.clone(),
        message: if c.body.is_empty() { c.title.clone() } else { format!("{}\n\n{}", c.title, c.body) },
        author: Author {
            name: c.author.name.clone(),
            email: c.author.email.clone(),
            key: c.author.key.clone(),
            account: c.author.account.clone(),
            note: Author::note_for(&c.author.key, &c.author.account),
        },
        when_ms: c.when_ms,
        deps: c.deps.clone(),
        head: c.head,
        via: c.via.as_ref().map(|v| Via {
            name: v.name.clone(),
            key: v.key.clone(),
            scope: v.scope.clone(),
            expires_ms: v.expires_ms,
            revoked: v.revoked,
        }),
        signature: match &c.signature {
            view::SigView::Unsigned => Signature::Unsigned,
            view::SigView::Valid { key, sealed, revoked, .. } => Signature::Valid { key: key.clone(), sealed: *sealed, revoked: *revoked },
            view::SigView::Invalid(why) => Signature::Invalid { reason: why.clone() },
        },
    }
}

// ---------------------------------------------------------------- accounts

async fn me(State(app): State<Shared>, headers: HeaderMap) -> Result<Json<User>, ApiError> {
    let c = caller(&app, &headers).await?;
    let a = c.require("user:read")?;
    Ok(Json(user_of(&app, a).await?))
}

#[derive(Deserialize)]
struct InboxQuery {
    #[serde(default)]
    limit: Option<i64>,
}

/// The caller's inbox; reading and clearing it needs `user:read`, since
/// it touches nothing but the caller's own notifications.
async fn notifications(
    State(app): State<Shared>,
    headers: HeaderMap,
    Query(q): Query<InboxQuery>,
) -> Result<Json<hub_api::Inbox>, ApiError> {
    let c = caller(&app, &headers).await?;
    let a = c.require("user:read")?;
    let limit = q.limit.unwrap_or(50).clamp(1, 200);
    let base = app.config.base_url().trim_end_matches('/').to_string();
    let rows = db::notify::inbox(&app.db, a.id, limit).await?;
    // Repositories by id, each looked up once (#305).
    let mut repos: std::collections::HashMap<i64, Option<String>> = std::collections::HashMap::new();
    for id in rows.iter().filter_map(|n| n.repo_id) {
        if let std::collections::hash_map::Entry::Vacant(e) = repos.entry(id) {
            e.insert(db::repos::get_by_id(&app.db, id).await?.map(|r| format!("{}/{}", r.owner, r.name)));
        }
    }
    let absolute = |u: String| if u.starts_with('/') { format!("{base}{u}") } else { u };
    let items = rows
        .into_iter()
        .map(|n| hub_api::Notification {
            id: n.id,
            at_ms: n.at_ms,
            label: crate::notify::label(&n.kind).map(String::from),
            kind: n.kind,
            title: n.title,
            url: absolute(n.url),
            actor: n.actor,
            read: n.read,
            repository: n.repo_id.and_then(|id| repos.get(&id).cloned().flatten()),
            reason: n.reason,
            thread: if n.thread.is_empty() { String::new() } else { absolute(n.thread) },
        })
        .collect();
    Ok(Json(hub_api::Inbox { unread: db::notify::unread(&app.db, a.id).await?, items }))
}

async fn notification_read(State(app): State<Shared>, headers: HeaderMap, Path(id): Path<i64>) -> Result<StatusCode, ApiError> {
    let c = caller(&app, &headers).await?;
    let a = c.require("user:read")?;
    db::notify::mark_read(&app.db, a.id, Some(id)).await?;
    Ok(StatusCode::NO_CONTENT)
}

async fn notifications_read_all(State(app): State<Shared>, headers: HeaderMap) -> Result<StatusCode, ApiError> {
    let c = caller(&app, &headers).await?;
    let a = c.require("user:read")?;
    db::notify::mark_read(&app.db, a.id, None).await?;
    Ok(StatusCode::NO_CONTENT)
}

async fn user_of(app: &Shared, a: &Account) -> Result<User, ApiError> {
    let keys = db::accounts::identities_of(&app.db, a.id).await?.into_iter().map(|i| i.key).collect();
    Ok(User { username: a.username.clone(), display_name: a.display_name.clone(), is_admin: a.is_admin, keys, created_ms: a.created_ms })
}

async fn user(State(app): State<Shared>, Path(name): Path<String>) -> Result<Json<User>, ApiError> {
    let a = db::accounts::account_by_name(&app.db, &name).await?.ok_or_else(|| not_found("no such account"))?;
    Ok(Json(user_of(&app, &a).await?))
}

async fn org(State(app): State<Shared>, Path(name): Path<String>) -> Result<Json<Organisation>, ApiError> {
    let o = db::accounts::org_by_name(&app.db, &name).await?.ok_or_else(|| not_found("no such organisation"))?;
    let members = db::accounts::org_members(&app.db, o.id).await?.into_iter().map(|(a, _)| a.username).collect();
    Ok(Json(Organisation { name: o.name, display_name: o.display_name, description: o.description, members }))
}

#[derive(Deserialize)]
struct SearchQuery {
    q: String,
}

async fn search(
    State(app): State<Shared>,
    headers: HeaderMap,
    Query(q): Query<SearchQuery>,
) -> Result<Json<Vec<serde_json::Value>>, ApiError> {
    let c = caller(&app, &headers).await?;
    let mut out = Vec::new();
    for h in db::notify::search(&app.db, &q.q, None, 50).await? {
        let Some(row) = db::repos::get_by_id(&app.db, h.repo_id).await? else { continue };
        let role = auth::roles::role_for(&app.db, c.account.as_ref(), &row).await?;
        if !auth::roles::allows(role, Access::Read) {
            continue;
        }
        out.push(
            serde_json::json!({ "kind": h.kind, "repository": row.slug(), "number": h.number, "title": h.title, "snippet": h.snippet }),
        );
    }
    Ok(Json(out))
}

// ------------------------------------------------------------ repositories

async fn list_repos(State(app): State<Shared>, headers: HeaderMap) -> Result<Json<Vec<Repository>>, ApiError> {
    let c = caller(&app, &headers).await?;
    let mut out = Vec::new();
    for r in db::repos::list(&app.db).await? {
        let role = auth::roles::role_for(&app.db, c.account.as_ref(), &r).await?;
        if auth::roles::allows(role, Access::Read) {
            out.push(repository(&app, &r));
        }
    }
    Ok(Json(out))
}

#[derive(Deserialize)]
struct UserReposQuery {
    /// Which: `owner`, `organization`, `collaborator`, comma-separated (all three by default).
    #[serde(default)]
    affiliation: Option<String>,
    /// The last `owner/name` of the previous page.
    #[serde(default)]
    after: Option<String>,
    #[serde(default)]
    limit: Option<usize>,
}

/// `GET /user/repos` (#302): the caller's repositories, their
/// organisations' and those they collaborate on, by `owner/name`, a page
/// at a time (`?after=owner/name&limit=`, at most 100, default 50).
/// `POST /user/runner-token` (repo:write): a one-time registration token
/// for a runner that serves the caller's own repositories and no one
/// else's, as a phone registers itself (oxygenhub-android#8). Like the
/// settings pages' tokens it lasts a day.
async fn user_runner_token(State(app): State<Shared>, headers: HeaderMap) -> Result<(StatusCode, Json<RunnerToken>), ApiError> {
    let c = caller(&app, &headers).await?;
    let me = c.require("repo:write")?.clone();
    let token = format!("flowreg_{}", crate::auth::random_hex(24));
    let scope = db::runners::Scope { owner: me.username.clone(), repo_id: None };
    db::runners::add_registration(&app.db, &blake3::hash(token.as_bytes()).to_hex(), &me.username, &scope).await?;
    db::accounts::audit(&app.db, Some(&me), "flow.runner.token", &me.username, "registration token for the caller's repositories (API)")
        .await
        .ok();
    Ok((StatusCode::CREATED, Json(RunnerToken { token, owner: me.username })))
}

/// `GET /user/proposals` (repo:read): what the dashboard lists, for apps;
/// with `?landable=true`, also what the caller can land now (#311).
async fn user_proposals(
    State(app): State<Shared>,
    headers: HeaderMap,
    Query(q): Query<UserProposalsQuery>,
) -> Result<Json<UserProposals>, ApiError> {
    let c = caller(&app, &headers).await?;
    let me = c.require("repo:read")?.clone();
    // As the dashboard: reviews in repositories the caller belongs to, its
    // own proposals in any it can still see.
    let member = db::accounts::visible_repo_ids(&app.db, me.id).await?;
    let seen: Vec<i64> = db::repos::list(&app.db)
        .await?
        .into_iter()
        .filter(|r| me.is_admin || r.visibility() != Visibility::Private || member.contains(&r.id))
        .map(|r| r.id)
        .collect();
    let base = app.config.base_url().trim_end_matches('/').to_string();
    let brief = |p: db::activity::ProposalLine| ProposalBrief {
        url: format!("{base}/{}/{}/proposal/{}", p.owner, p.name, p.number),
        repository: format!("{}/{}", p.owner, p.name),
        number: p.number,
        title: p.title,
        author: p.author,
        state: match p.state.as_str() {
            "draft" => ProposalState::Draft,
            "landed" => ProposalState::Landed,
            "closed" => ProposalState::Closed,
            _ => ProposalState::Open,
        },
        conflicted: p.conflicted,
        updated_ms: p.updated_ms,
    };
    let landable = if q.landable { landable_for(&app, &c, &member, &base).await? } else { Vec::new() };
    Ok(Json(UserProposals {
        review: db::activity::awaiting_review(&app.db, me.id, &member).await?.into_iter().map(brief).collect(),
        authored: db::activity::authored(&app.db, me.id, &seen).await?.into_iter().map(brief).collect(),
        landable,
    }))
}

/// The open proposals the caller could land now (#311): in repositories
/// it belongs to and can write to, whose verdict has no blockers. Each
/// projected state is worked out four at a time, as `proposals` does
/// (#171); one that cannot be is left out rather than failing the list.
async fn landable_for(app: &Shared, c: &Caller, member: &[i64], base: &str) -> Result<Vec<ProposalBrief>, ApiError> {
    use futures::StreamExt;
    let mut todo = Vec::new();
    for row in db::repos::list(&app.db).await?.into_iter().filter(|r| member.contains(&r.id) && !r.is_drop()) {
        let role = auth::roles::role_for(&app.db, c.account.as_ref(), &row).await?;
        if !auth::roles::allows(role, Access::Write) {
            continue;
        }
        let Some(repo) = RepoName::new(&row.owner, &row.name) else { continue };
        for p in db::proposals::list(&app.db, row.id, &["open"]).await? {
            todo.push((repo.clone(), row.clone(), p));
        }
    }
    let found: Vec<Option<ProposalBrief>> = futures::stream::iter(todo)
        .map(|(repo, row, p)| {
            let (app, base) = (app.clone(), base.to_string());
            async move {
                let (number, title, author, updated_ms) = (p.number, p.title.clone(), p.author.clone(), p.updated_ms);
                let loaded = crate::web::proposals::load_summary(&app, &repo, p).await.ok()?;
                let v = crate::web::proposals::verdict(&app, &loaded, row.id).await.ok()?;
                v.blockers.is_empty().then(|| ProposalBrief {
                    url: format!("{base}/{}/{}/proposal/{number}", row.owner, row.name),
                    repository: format!("{}/{}", row.owner, row.name),
                    number,
                    title,
                    author,
                    state: ProposalState::Open,
                    conflicted: loaded.conflicted,
                    updated_ms,
                })
            }
        })
        .buffered(4)
        .collect()
        .await;
    Ok(found.into_iter().flatten().collect())
}

async fn user_repos(
    State(app): State<Shared>,
    headers: HeaderMap,
    Query(q): Query<UserReposQuery>,
) -> Result<Json<Vec<Repository>>, ApiError> {
    let c = caller(&app, &headers).await?;
    let me = c.require("repo:read")?.clone();
    let wanted: Vec<String> = q
        .affiliation
        .as_deref()
        .unwrap_or("owner,organization,collaborator")
        .split(',')
        .map(|s| s.trim().to_ascii_lowercase())
        .filter(|s| !s.is_empty())
        .collect();
    if let Some(bad) = wanted.iter().find(|w| !["owner", "organization", "collaborator"].contains(&w.as_str())) {
        return Err(ApiError(StatusCode::BAD_REQUEST, format!("unknown affiliation {bad:?}: owner, organization or collaborator")));
    }
    let orgs: Vec<String> = db::accounts::orgs_of(&app.db, me.id).await?.into_iter().map(|(o, _)| o.name).collect();
    let limit = q.limit.unwrap_or(50).clamp(1, 100);
    let mut rows = db::repos::list(&app.db).await?;
    rows.sort_by(|a, b| (&a.owner, &a.name).cmp(&(&b.owner, &b.name)));
    let mut out = Vec::new();
    for r in rows {
        if let Some(after) = q.after.as_deref() {
            if format!("{}/{}", r.owner, r.name).as_str() <= after {
                continue;
            }
        }
        let mine = (wanted.iter().any(|w| w == "owner") && r.owner == me.username)
            || (wanted.iter().any(|w| w == "organization") && orgs.contains(&r.owner))
            || (wanted.iter().any(|w| w == "collaborator") && db::accounts::collaborator_role(&app.db, r.id, me.id).await?.is_some());
        if !mine || !auth::roles::allows(auth::roles::role_for(&app.db, Some(&me), &r).await?, Access::Read) {
            continue;
        }
        out.push(repository(&app, &r));
        if out.len() == limit {
            break;
        }
    }
    Ok(Json(out))
}

/// `GET /user/orgs` (#302): the organisations the caller belongs to.
async fn user_orgs(State(app): State<Shared>, headers: HeaderMap) -> Result<Json<Vec<hub_api::UserOrg>>, ApiError> {
    let c = caller(&app, &headers).await?;
    let me = c.require("user:read")?;
    let orgs = db::accounts::orgs_of(&app.db, me.id).await?;
    Ok(Json(orgs.into_iter().map(|(o, role)| hub_api::UserOrg { name: o.name, display_name: o.display_name, role }).collect()))
}

async fn create_repo(
    State(app): State<Shared>,
    headers: HeaderMap,
    Json(body): Json<NewRepository>,
) -> Result<(StatusCode, Json<Repository>), ApiError> {
    let c = caller(&app, &headers).await?;
    let me = c.require("repo:admin")?;
    let name = RepoName::new(&body.owner, &body.name).ok_or_else(|| ApiError(StatusCode::BAD_REQUEST, "invalid owner or name".into()))?;
    if name.name.ends_with(crate::wiki::SUFFIX) {
        return Err(ApiError(StatusCode::BAD_REQUEST, "a name cannot end in .wiki: that is the address of a repository's wiki".into()));
    }
    if !auth::roles::may_create_under(&app.db, me, &name.owner).await? {
        return Err(forbidden("you cannot create repositories under that owner"));
    }
    if db::repos::get(&app.db, &name.owner, &name.name).await?.is_some() || app.repos.exists(&name) {
        return Err(ApiError(StatusCode::CONFLICT, "that repository exists".into()));
    }
    app.repos.create(&name, None)?;
    let row = db::repos::create(&app.db, &name.owner, &name.name, &body.description, body.visibility).await?;
    db::accounts::audit(&app.db, Some(me), "repo.created", &name.to_string(), "api").await.ok();
    Ok((StatusCode::CREATED, Json(repository(&app, &row))))
}

async fn get_repo(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name)): Path<(String, String)>,
) -> Result<Json<Repository>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (_, row, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    Ok(Json(repository(&app, &row)))
}

async fn bookmarks(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name)): Path<(String, String)>,
) -> Result<Json<Vec<Bookmark>>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (repo, row, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let default = row.default_bookmark.clone();
    let list = app.repos.read(&repo, move |r, cache| view::bookmarks(r, cache, &default)).await?;
    Ok(Json(list.into_iter().map(|b| Bookmark { name: b.name, heads: b.heads, changes: b.changes, default: b.default }).collect()))
}

#[derive(serde::Deserialize)]
struct BackupSetting {
    /// `owner` (with its owner's), `hourly`, `daily` or `off`.
    backup: String,
}

/// `PUT /repos/{owner}/{name}/backup {"backup": ...}`: this repository's
/// backup (docs/backups.md §5). Owners and admins.
async fn set_backup(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name)): Path<(String, String)>,
    Json(b): Json<BackupSetting>,
) -> Result<Json<serde_json::Value>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (_, row, _) = reach(&app, &c, &owner, &name, Access::Maintain).await?;
    let setting = match b.backup.as_str() {
        "owner" => "",
        "hourly" | "daily" | "off" => b.backup.as_str(),
        _ => return Err(ApiError(StatusCode::BAD_REQUEST, "backup is owner, hourly, daily or off".into())),
    };
    db::repos::set_backup(&app.db, row.id, setting).await?;
    db::accounts::audit(&app.db, c.account.as_ref(), "repo.backup", &format!("{owner}/{name}"), &b.backup).await.ok();
    Ok(Json(serde_json::json!({ "backup": b.backup })))
}

#[derive(serde::Deserialize)]
struct DiffusionSetting {
    /// `off`, `green`, `any`, or `default` (the site's).
    follow: String,
    /// `auto` or `propose`; absent keeps it as it is.
    #[serde(default)]
    land: Option<String>,
}

/// `PUT /repos/{owner}/{name}/diffusion {"follow": ...}`: whether this
/// repository follows the upstreams it pins (#148). Owners and admins.
async fn set_diffusion(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name)): Path<(String, String)>,
    Json(d): Json<DiffusionSetting>,
) -> Result<Json<serde_json::Value>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (_, row, _) = reach(&app, &c, &owner, &name, Access::Maintain).await?;
    let setting = match d.follow.as_str() {
        "off" | "green" | "any" => d.follow.as_str(),
        "default" => "",
        _ => return Err(ApiError(StatusCode::BAD_REQUEST, "follow is off, green, any or default".into())),
    };
    let land = match d.land.as_deref() {
        Some(l @ ("auto" | "propose")) => Some(l),
        None => None,
        Some(_) => return Err(ApiError(StatusCode::BAD_REQUEST, "land is auto or propose".into())),
    };
    db::repos::set_diffusion(&app.db, row.id, setting).await?;
    if let Some(l) = land {
        db::repos::set_diffusion_land(&app.db, row.id, l).await?;
    }
    db::accounts::audit(
        &app.db,
        c.account.as_ref(),
        "repo.diffusion",
        &format!("{owner}/{name}"),
        if setting.is_empty() { "default" } else { setting },
    )
    .await
    .ok();
    let row = db::repos::get_by_id(&app.db, row.id).await?.unwrap_or(row);
    let rule = crate::diffusion::rule(&app.config.diffusion.follow, &row, None, "");
    // Turned on: bumped at once to where its upstreams are (#148).
    if rule.follow != crate::diffusion::Follow::Off {
        let (app, row) = (app.clone(), row.clone());
        tokio::spawn(async move { crate::diffusion::catch_up(&app, &row).await });
    }
    if land == Some("auto") {
        let (app, row) = (app.clone(), row.clone());
        tokio::spawn(async move { crate::diffusion::land_ready(&app, &row).await });
    }
    Ok(Json(
        serde_json::json!({ "follow": rule.follow, "from": rule.from, "land": if row.diffusion_land == "auto" { "auto" } else { "propose" } }),
    ))
}

/// `GET /repos/{owner}/{name}/consumers`: the repositories that pin this
/// one as a subrepo and that the caller may read, each with its pin and
/// how far behind this repository's default bookmark it is (#148).
async fn consumers(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name)): Path<(String, String)>,
) -> Result<Json<Vec<crate::diffusion::Consumer>>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (_, row, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    Ok(Json(crate::diffusion::consumers(&app, &row, c.account.as_ref()).await?))
}

/// `GET /repos/{owner}/{name}/diffusion`: what this repository takes from
/// and what it diffuses to, as its Diffusion tab shows them (#153).
async fn diffusion(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name)): Path<(String, String)>,
) -> Result<Json<hub_api::Diffusion>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (_, row, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let slug = format!("{owner}/{name}");
    let takes_from = crate::diffusion::follows(&app, &row, c.account.as_ref())
        .await
        .iter()
        .map(|(up, p)| p.api(&format!("{}/{}", up.owner, up.name)))
        .collect();
    let diffuses_to = crate::diffusion::consumers(&app, &row, c.account.as_ref()).await?.iter().map(|p| p.api(&slug)).collect();
    Ok(Json(hub_api::Diffusion { takes_from, diffuses_to }))
}

async fn tags(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name)): Path<(String, String)>,
) -> Result<Json<Vec<Tag>>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (repo, _, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let list = app.repos.read(&repo, |r, _| view::tags(r)).await?;
    Ok(Json(list.into_iter().map(|t| Tag { name: t.name, heads: t.heads, message: t.message, signer: t.signer }).collect()))
}

/// `POST …/tags` (#295): what the Tags page's Create does.
async fn create_tag(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name)): Path<(String, String)>,
    Json(body): Json<NewTag>,
) -> Result<(StatusCode, Json<Tag>), ApiError> {
    let c = caller(&app, &headers).await?;
    let me = c.require("repo:write")?.clone();
    let (repo, row, _) = reach(&app, &c, &owner, &name, Access::Write).await?;
    let made = crate::tags::create(
        &app,
        &row,
        &repo,
        &me,
        &body.name,
        body.target.as_deref().unwrap_or(""),
        body.message.as_deref().unwrap_or(""),
    )
    .await
    .map_err(|m| ApiError(StatusCode::BAD_REQUEST, m))?;
    let t = app
        .repos
        .read(&repo, |r, _| view::tags(r))
        .await?
        .into_iter()
        .find(|t| t.name == made.name)
        .ok_or_else(|| not_found("no such tag"))?;
    Ok((StatusCode::CREATED, Json(Tag { name: t.name, heads: t.heads, message: t.message, signer: t.signer })))
}

#[derive(Deserialize)]
struct WithdrawQuery {
    #[serde(default)]
    reason: String,
}

/// `DELETE …/tags/{tag}?reason=…` (#301): what the Tags page's Withdraw
/// does. Maintainers; refused (409) while a release uses the tag.
async fn withdraw_tag(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, tag)): Path<(String, String, String)>,
    Query(q): Query<WithdrawQuery>,
) -> Result<StatusCode, ApiError> {
    let c = caller(&app, &headers).await?;
    let me = c.require("repo:write")?.clone();
    let (repo, row, _) = reach(&app, &c, &owner, &name, Access::Maintain).await?;
    if db::releases::get(&app.db, row.id, &tag).await?.is_some() {
        return Err(ApiError(StatusCode::CONFLICT, format!("a release uses {tag}: delete the release first")));
    }
    crate::tags::withdraw(&app, &row, &repo, &me, &tag, &q.reason).await.map_err(|m| ApiError(StatusCode::BAD_REQUEST, m))?;
    Ok(StatusCode::NO_CONTENT)
}

#[derive(Deserialize)]
struct HistoryQuery {
    path: Option<String>,
    offset: Option<usize>,
    limit: Option<usize>,
    /// A revset (Oxygen's docs/revset_query_language.md) in place of the
    /// reference's whole history; the reference still gives the labels.
    r: Option<String>,
}

async fn history(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, r)): Path<(String, String, String)>,
    Query(q): Query<HistoryQuery>,
) -> Result<Json<History>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (repo, _, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let (offset, limit) = (q.offset.unwrap_or(0), q.limit.unwrap_or(50).min(500));
    let revset = q.r.clone().filter(|s| !s.trim().is_empty());
    let by_revset = revset.is_some();
    let h = app
        .repos
        .read(&repo, move |repo, cache| {
            let target = view::resolve(repo, cache, &r)?;
            match &revset {
                Some(rs) => view::history_revset(repo, cache, target, rs, offset, limit),
                None => view::history(repo, cache, target, q.path.as_deref(), offset, limit),
            }
        })
        .await
        .map_err(|e| {
            // A revset that does not parse, names nothing, or goes past the
            // budget is the caller's to fix.
            if by_revset {
                ApiError(StatusCode::BAD_REQUEST, e.to_string())
            } else {
                e.into()
            }
        })?;
    let mut entries = h.entries;
    crate::web::attribute(&app, &mut entries.iter_mut().collect::<Vec<_>>()).await;
    Ok(Json(History {
        reference: h.target.label,
        heads: h.target.heads.iter().map(|x| x.to_hex()).collect(),
        total: h.total,
        offset: h.offset,
        changes: entries.iter().map(summary).collect(),
    }))
}

async fn change(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, hash)): Path<(String, String, String)>,
) -> Result<Json<ChangeDetail>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (repo, _, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let d = app
        .repos
        .read(&repo, move |repo, cache| {
            let h = view::resolve_change(repo, cache, &hash)?;
            view::change(repo, cache, &h)
        })
        .await?;
    let mut v = d.view;
    crate::web::attribute(&app, &mut [&mut v]).await;
    let files = crate::web::history::render_files(&d.files, &d.bases).into_iter().map(file_change).collect();
    Ok(Json(ChangeDetail {
        body: v.body.clone(),
        change: summary(&v),
        dependents: d.dependents.iter().map(|x| x.hash.clone()).collect(),
        in_bookmarks: d.in_bookmarks,
        in_tags: d.in_tags,
        files,
    }))
}

fn file_change(f: crate::web::history::FileRows) -> FileChange {
    use crate::render::diff::Kind;
    let truncated = f.lines.len() > hub_api::DIFF_LINES;
    let lines = f
        .lines
        .into_iter()
        .take(hub_api::DIFF_LINES)
        .map(|l| DiffLine {
            kind: match l.kind {
                Kind::Context => "context",
                Kind::Add => "add",
                Kind::Del => "del",
                Kind::Gap => "gap",
            }
            .into(),
            old: l.old_no,
            new: l.new_no,
            text: l.text,
        })
        .collect();
    FileChange { path: f.path, kind: f.kind, from: f.from, added: f.added, removed: f.removed, lines, truncated }
}

fn entry(e: &view::Entry) -> TreeEntry {
    TreeEntry {
        name: e.name.clone(),
        path: e.path.clone(),
        kind: match e.kind {
            view::EntryKind::Dir => "dir",
            view::EntryKind::File => "file",
            view::EntryKind::Symlink => "symlink",
            view::EntryKind::Subrepo => "subrepo",
        }
        .into(),
        exec: e.exec,
        size: e.size,
        conflicted: e.conflicted,
    }
}

async fn tree_root(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, r)): Path<(String, String, String)>,
) -> Result<Json<Vec<TreeEntry>>, ApiError> {
    tree(State(app), headers, Path((owner, name, r, String::new()))).await
}

async fn tree(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, r, path)): Path<(String, String, String, String)>,
) -> Result<Json<Vec<TreeEntry>>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (repo, _, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let t = app
        .repos
        .read(&repo, move |repo, cache| {
            let target = view::resolve(repo, cache, &r)?;
            view::tree(repo, cache, target, &path)
        })
        .await?;
    Ok(Json(t.entries.iter().map(entry).collect()))
}

async fn file(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, r, path)): Path<(String, String, String, String)>,
) -> Result<Response, ApiError> {
    let c = caller(&app, &headers).await?;
    let (repo, _, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let limit = app.config.limits.render_limit.0;
    let f = app
        .repos
        .read(&repo, move |repo, cache| {
            let target = view::resolve(repo, cache, &r)?;
            view::file(repo, cache, target, &path, limit)
        })
        .await?;
    Ok(crate::web::raw(f.bytes, &f.name, false))
}

async fn blame(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, r, path)): Path<(String, String, String, String)>,
) -> Result<Json<Vec<BlameLine>>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (repo, _, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let limit = app.config.limits.render_limit.0;
    let b = app
        .repos
        .read(&repo, move |repo, cache| {
            let target = view::resolve(repo, cache, &r)?;
            view::blame(repo, cache, target, &path, limit)
        })
        .await?;
    Ok(Json(
        b.lines
            .into_iter()
            .map(|l| BlameLine {
                line: l.line,
                change: l.hash.to_hex(),
                index: l.index,
                author: l.author,
                when_ms: l.when_ms,
                text: String::from_utf8_lossy(&l.text).into_owned(),
            })
            .collect(),
    ))
}

async fn conflicts(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name)): Path<(String, String)>,
) -> Result<Json<Vec<Conflict>>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (repo, _, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let list = app.repos.read(&repo, view::conflicts).await?;
    Ok(Json(
        list.into_iter()
            .map(|c| Conflict {
                bookmark: c.bookmark,
                path: c.path,
                kind: c.kind,
                contributors: c.contributors.iter().map(|x| x.hash.clone()).collect(),
            })
            .collect(),
    ))
}

/// `GET /repos/{o}/{n}/releases/trust/{tag}`: a release's trust report
/// (hub spec §9.1), as the page's JSON export.
async fn release_trust(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, tag)): Path<(String, String, String)>,
) -> Result<Json<crate::web::release_trust::ReleaseTrust>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (repo, row, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    match crate::web::release_trust::report(&app, &repo, &row, &tag).await.map_err(|m| ApiError(StatusCode::INTERNAL_SERVER_ERROR, m))? {
        Some(t) => Ok(Json(t)),
        None => Err(ApiError(StatusCode::NOT_FOUND, format!("no release {tag}"))),
    }
}

async fn trust(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name)): Path<(String, String)>,
) -> Result<Json<Trust>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (repo, _, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let key = app.hub_key.key;
    let t = app.repos.read(&repo, move |r, cache| view::trust(r, cache, &key)).await?;
    Ok(Json(Trust {
        policy: t.policy.map(|p| Policy {
            serial: p.serial,
            expires_ms: p.expires_ms,
            roots: p.roots.iter().map(|k| k.key.clone()).collect(),
            root_threshold: p.root_threshold,
            rules: p
                .rules
                .iter()
                .map(|r| Rule {
                    pattern: r.pattern.clone(),
                    keys: r.keys.iter().map(|k| k.key.clone()).collect(),
                    threshold: r.threshold,
                    require: r.require.clone(),
                    allow_conflicts: r.allow_conflicts,
                })
                .collect(),
        }),
        signed: t.verification.signed,
        sealed: t.verification.sealed,
        unsigned: t.verification.unsigned,
        invalid: t.verification.invalid.iter().map(|(h, _)| h.clone()).collect(),
        hub_key: t.hub_key,
    }))
}

async fn pushes(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name)): Path<(String, String)>,
) -> Result<Json<Vec<Push>>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (_, row, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let rows = db::repos::pushes(&app.db, row.id, 200).await?;
    Ok(Json(
        rows.into_iter()
            .map(|p| Push {
                at_ms: p.at_ms,
                pusher: p.pusher,
                reference: p.reference,
                ok: p.ok,
                reason: p.reason,
                old_state: p.old_state,
                new_state: p.new_state,
                heads: p.heads,
                changes: p.changes,
            })
            .collect(),
    ))
}

// --------------------------------------------------------------- proposals

/// `GET /repos/{o}/{n}/proposals?state=open|draft|landed|closed|all&limit=N`:
/// open ones (drafts too) by default, newest first, the first `limit` if
/// given (#331).
async fn proposals(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name)): Path<(String, String)>,
    Query(q): Query<ProposalsQuery>,
) -> Result<Json<Vec<Proposal>>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (repo, row, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let states: &[&str] = match q.state.as_deref().unwrap_or("open") {
        "open" => &["open", "draft"],
        "draft" => &["draft"],
        "landed" => &["landed"],
        "closed" => &["closed"],
        "all" => &["open", "draft", "landed", "closed"],
        other => return Err(ApiError(StatusCode::BAD_REQUEST, format!("state is open, draft, landed, closed or all, not {other:?}"))),
    };
    // Each proposal's projected state is worked out from the store, which
    // for a bucket-backed repository is many slow round trips: four at a
    // time, in order, each under the repository's read lock only. One at
    // a time took 28 s for a repository on GCS (oxygenhub#171). A landed
    // or closed one is as recorded, not projected again (#331).
    use futures::StreamExt;
    let mut rows = db::proposals::list(&app.db, row.id, states).await?;
    if let Some(limit) = q.limit {
        rows.truncate(limit);
    }
    let out: Vec<Result<Proposal, ApiError>> = futures::stream::iter(rows)
        .map(|p| {
            let (app, repo, owner, name, id) = (app.clone(), repo.clone(), owner.clone(), name.clone(), row.id);
            async move {
                let loaded = crate::web::proposals::load_for_api(&app, &repo, p).await?;
                let v = crate::web::proposals::verdict(&app, &loaded, id).await?;
                Ok(crate::web::proposals::to_api(&app, &owner, &name, &loaded, &v, None).await)
            }
        })
        .buffered(4)
        .collect()
        .await;
    Ok(Json(out.into_iter().collect::<Result<Vec<_>, _>>()?))
}

async fn proposal(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, number)): Path<(String, String, i64)>,
) -> Result<Json<Proposal>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (repo, row, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let p = db::proposals::get(&app.db, row.id, number).await?.ok_or_else(|| not_found("no such proposal"))?;
    let source_url = match p.source_repo_id {
        Some(id) => db::repos::get_by_id(&app.db, id).await?.map(|r| format!("{}/{}", app.config.base_url(), r.slug())),
        None => None,
    };
    let loaded = crate::web::proposals::load_for_api(&app, &repo, p).await?;
    let v = crate::web::proposals::verdict(&app, &loaded, row.id).await?;
    Ok(Json(crate::web::proposals::to_api(&app, &owner, &name, &loaded, &v, source_url).await))
}

/// `PATCH /repos/{o}/{n}/proposals/{number}`: change the title or body,
/// keeping what is not given; the author or a maintainer, as on the page
/// (oxygenhub#76). The target is changed on the page, which re-projects.
async fn edit_proposal(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, number)): Path<(String, String, i64)>,
    Json(body): Json<hub_api::ProposalEdit>,
) -> Result<Json<Proposal>, ApiError> {
    let c = caller(&app, &headers).await?;
    let me = c.require("proposals:write").or_else(|_| c.require("repo:write"))?.clone();
    let (repo, row, role) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let p = db::proposals::get(&app.db, row.id, number).await?.ok_or_else(|| not_found("no such proposal"))?;
    let text = body.title.is_some() || body.body.is_some();
    if text && Some(me.id) != p.author_id && role < Role::Maintain {
        return Err(ApiError(StatusCode::FORBIDDEN, "only the proposal's author or a maintainer can edit it".into()));
    }
    if body.labels.is_some() && role < Role::Triage {
        return Err(forbidden("setting labels needs triage access"));
    }
    // Every name is checked before anything changes.
    let labels = resolve_triage(&app, row.id, body.labels.as_deref(), None, None).await?.labels;
    if text {
        let title = match body.title.as_deref().map(str::trim) {
            Some("") => return Err(ApiError(StatusCode::BAD_REQUEST, "a proposal needs a title".into())),
            Some(t) => t,
            None => p.title.as_str(),
        };
        let text = body.body.as_deref().map(str::trim).unwrap_or(&p.body);
        db::proposals::edit(&app.db, p.id, title, text, &p.target).await?;
        db::proposals::add_event(&app.db, p.id, &me.username, "edited", "").await.ok();
    }
    if let Some(want) = labels {
        let have = db::issues::proposal_labels(&app.db, p.id).await?;
        for l in &have {
            if !want.iter().any(|w| w.id == l.id) {
                db::issues::set_proposal_label(&app.db, p.id, l.id, false).await?;
            }
        }
        for w in &want {
            if !have.iter().any(|l| l.id == w.id) {
                db::issues::set_proposal_label(&app.db, p.id, w.id, true).await?;
            }
        }
        let names: Vec<&str> = want.iter().map(|l| l.name.as_str()).collect();
        db::proposals::add_event(&app.db, p.id, &me.username, "set labels", &names.join(", ")).await.ok();
    }
    // `draft` says the same as `state`, in the words of creation (#313).
    let want = match (body.state.as_deref(), body.draft) {
        (Some(s), Some(d)) if (s == "draft") != d => {
            return Err(ApiError(StatusCode::BAD_REQUEST, format!("state {s:?} and draft {d} disagree")));
        }
        (Some(s), _) => Some(s),
        (None, Some(true)) => Some("draft"),
        (None, Some(false)) => Some("open"),
        (None, None) => None,
    };
    if let Some(want) = want {
        if Some(me.id) != p.author_id && role < Role::Triage {
            return Err(ApiError(
                StatusCode::FORBIDDEN,
                "only the proposal's author or someone with triage access can close, reopen or change whether it is a draft".into(),
            ));
        }
        // The page's transitions: a draft is made ready (open), and an open
        // proposal turned back into a draft.
        let new_state = match (want, p.state.as_str()) {
            ("closed", "open" | "draft") => "closed",
            ("open", "closed" | "draft") => "open",
            ("draft", "open") => "draft",
            (w, now) if w == now => now,
            ("closed" | "open" | "draft", now) => {
                return Err(ApiError(StatusCode::CONFLICT, format!("a proposal that is {now} cannot become {want}")))
            }
            _ => return Err(ApiError(StatusCode::BAD_REQUEST, "state is closed, open or draft".into())),
        };
        if new_state != p.state {
            db::proposals::set_state(&app.db, p.id, new_state, "").await?;
            db::proposals::add_event(&app.db, p.id, &me.username, new_state, "").await.ok();
            crate::hooks::emit(&app, &row, &format!("proposal.{new_state}"), &me.username, serde_json::json!({ "number": number })).await;
        }
    }
    let p = db::proposals::get(&app.db, row.id, number).await?.ok_or_else(|| not_found("no such proposal"))?;
    let source_url = match p.source_repo_id {
        Some(id) => db::repos::get_by_id(&app.db, id).await?.map(|r| format!("{}/{}", app.config.base_url(), r.slug())),
        None => None,
    };
    let loaded = crate::web::proposals::load_for_api(&app, &repo, p).await?;
    let v = crate::web::proposals::verdict(&app, &loaded, row.id).await?;
    Ok(Json(crate::web::proposals::to_api(&app, &owner, &name, &loaded, &v, source_url).await))
}

/// `POST /repos/{o}/{n}/proposals/{number}/land` (repo:write): land it as
/// the page's Land button does; `409` with the blockers when it cannot.
/// `{"over_checks": "reason"}` lands over required checks that have not
/// passed, for maintainers (#261).
async fn land_proposal(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, number)): Path<(String, String, i64)>,
    body: axum::body::Bytes,
) -> Result<Json<Proposal>, ApiError> {
    let c = caller(&app, &headers).await?;
    let me = c.require("repo:write")?.clone();
    let over_checks: Option<String> = if body.iter().all(u8::is_ascii_whitespace) {
        None
    } else {
        serde_json::from_slice::<serde_json::Value>(&body)
            .map_err(|_| ApiError(StatusCode::BAD_REQUEST, "the body is JSON: {} or {\"over_checks\": \"reason\"}".into()))?
            .get("over_checks")
            .and_then(|v| v.as_str())
            .map(String::from)
    };
    let need = if over_checks.is_some() { Access::Maintain } else { Access::Write };
    let (repo, row, _) = reach(&app, &c, &owner, &name, need).await?;
    let via = format!("api (token {})", c.token);
    match crate::web::proposals::land_as(&app, &repo, &row, &me, number, &via, false, over_checks.as_deref()).await {
        Ok(_) => proposal(State(app), headers, Path((owner, name, number))).await,
        Err(crate::web::proposals::Landing::NotFound) => Err(not_found("no such proposal")),
        Err(crate::web::proposals::Landing::Refused(m)) => Err(ApiError(StatusCode::CONFLICT, m)),
    }
}

/// `POST /repos/{o}/{n}/proposals/{number}/auto-land` (repo:write, #261):
/// land it when its checks pass; at once if they already have.
async fn auto_land_on(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, number)): Path<(String, String, i64)>,
) -> Result<Json<Proposal>, ApiError> {
    auto_land_set(&app, &headers, &owner, &name, number, true).await?;
    proposal(State(app), headers, Path((owner, name, number))).await
}

/// `DELETE …/auto-land`: it will not land by itself.
async fn auto_land_off(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, number)): Path<(String, String, i64)>,
) -> Result<Json<Proposal>, ApiError> {
    auto_land_set(&app, &headers, &owner, &name, number, false).await?;
    proposal(State(app), headers, Path((owner, name, number))).await
}

async fn auto_land_set(app: &Shared, headers: &HeaderMap, owner: &str, name: &str, number: i64, on: bool) -> Result<(), ApiError> {
    let c = caller(app, headers).await?;
    let me = c.require("repo:write")?.clone();
    let (_, row, _) = reach(app, &c, owner, name, Access::Write).await?;
    let p = db::proposals::get(&app.db, row.id, number).await?.ok_or_else(|| not_found("no such proposal"))?;
    if !p.is_open() {
        return Err(ApiError(StatusCode::CONFLICT, format!("the proposal is {}", p.state)));
    }
    crate::autoland::set(app, &row, &p, &me, on).await?;
    Ok(())
}

/// The files a proposal changes (hub spec §12.1).
async fn proposal_files(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, number)): Path<(String, String, i64)>,
) -> Result<Json<Vec<hub_api::ProposalFile>>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (repo, row, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let p = db::proposals::get(&app.db, row.id, number).await?.ok_or_else(|| not_found("no such proposal"))?;
    let loaded = crate::web::proposals::load(&app, &repo, p).await?;
    Ok(Json(
        loaded
            .files
            .iter()
            .map(|f| hub_api::ProposalFile {
                path: f.path.clone(),
                from: f.from.clone(),
                kind: f.kind.clone(),
                added: f.added,
                removed: f.removed,
            })
            .collect(),
    ))
}

/// One file's bytes on a side of a proposal: `base` is the target's
/// state, `head` the projected state. 404 when the file does not exist
/// on that side.
async fn proposal_content(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, number, side, path)): Path<(String, String, i64, String, String)>,
) -> Result<Response, ApiError> {
    let c = caller(&app, &headers).await?;
    let (repo, row, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let p = db::proposals::get(&app.db, row.id, number).await?.ok_or_else(|| not_found("no such proposal"))?;
    let loaded = crate::web::proposals::load_summary(&app, &repo, p).await?;
    let heads = match side.as_str() {
        "base" => loaded.target_heads,
        "head" => loaded.heads,
        _ => return Err(ApiError(StatusCode::BAD_REQUEST, "the side is base or head".into())),
    };
    let limit = app.config.limits.render_limit.0;
    let target = view::RefTarget { label: side, kind: view::RefKind::Change, heads };
    let f = app.repos.read(&repo, move |repo, cache| view::file(repo, cache, target, &path, limit)).await?;
    Ok(crate::web::raw(f.bytes, &f.name, false))
}

async fn create_proposal(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name)): Path<(String, String)>,
    Json(body): Json<NewProposal>,
) -> Result<(StatusCode, Json<Proposal>), ApiError> {
    let c = caller(&app, &headers).await?;
    let me = c.require("proposals:write").or_else(|_| c.require("repo:write"))?.clone();
    let (repo, row, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let created =
        crate::web::proposals::open_proposal(&app, &repo, &row, &me, &body.title, &body.body, &body.target, &body.source, body.draft)
            .await
            .map_err(|e| ApiError(StatusCode::BAD_REQUEST, e))?;
    let loaded = crate::web::proposals::load_summary(&app, &repo, created).await?;
    let v = crate::web::proposals::verdict(&app, &loaded, row.id).await?;
    Ok((StatusCode::CREATED, Json(crate::web::proposals::to_api(&app, &owner, &name, &loaded, &v, None).await)))
}

fn comment_of(c: &db::proposals::CommentRow) -> Comment {
    Comment {
        id: c.id,
        author: c.author.clone(),
        body: c.body.clone(),
        created_ms: c.created_ms,
        path: if c.path.is_empty() { None } else { Some(c.path.clone()) },
        anchor: if c.anchor_change.is_empty() {
            None
        } else {
            Some(Atom { change: c.anchor_change.clone(), index: c.anchor_index as u32 })
        },
        line: None,
        resolved: c.resolved,
    }
}

async fn proposal_comments(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, number)): Path<(String, String, i64)>,
) -> Result<Json<Vec<Comment>>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (_, row, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let p = db::proposals::get(&app.db, row.id, number).await?.ok_or_else(|| not_found("no such proposal"))?;
    let mut out: Vec<Comment> = db::proposals::comments(&app.db, p.id).await?.iter().map(comment_of).collect();
    // Place anchored comments on their line of the projected state.
    let paths: std::collections::BTreeSet<String> = out.iter().filter(|c| c.anchor.is_some()).filter_map(|c| c.path.clone()).collect();
    if !paths.is_empty() {
        let repo = RepoName::new(&owner, &name).ok_or_else(|| not_found("no such repository"))?;
        let heads = crate::web::proposals::load_summary(&app, &repo, p).await?.heads;
        let lines = app
            .repos
            .read(&repo, move |r, _| {
                let mut at = std::collections::HashMap::new();
                for path in paths {
                    // A file the projection removed has no lines to place a comment on.
                    for l in r.blame_in(&path, &heads).unwrap_or_default() {
                        at.insert((path.clone(), l.hash.to_hex(), l.index), l.line);
                    }
                }
                Ok(at)
            })
            .await?;
        for c in &mut out {
            if let (Some(path), Some(a)) = (&c.path, &c.anchor) {
                c.line = lines.get(&(path.clone(), a.change.clone(), a.index)).copied();
            }
        }
    }
    Ok(Json(out))
}

async fn proposal_comment(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, number)): Path<(String, String, i64)>,
    Json(body): Json<NewComment>,
) -> Result<(StatusCode, Json<Comment>), ApiError> {
    let c = caller(&app, &headers).await?;
    let me = c.require("proposals:write").or_else(|_| c.require("repo:write"))?.clone();
    let (_, row, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let p = db::proposals::get(&app.db, row.id, number).await?.ok_or_else(|| not_found("no such proposal"))?;
    if body.body.trim().is_empty() {
        return Err(ApiError(StatusCode::BAD_REQUEST, "an empty comment says nothing".into()));
    }
    let (repo, _) = (RepoName::new(&owner, &name).ok_or_else(|| not_found("no such repository"))?, ());
    let anchor = match (body.path.as_deref().map(|x| x.trim_matches('/')), body.line) {
        (Some(path), Some(line)) if !path.is_empty() => {
            let loaded = crate::web::proposals::load(&app, &repo, p.clone()).await?;
            let (heads, file) = (loaded.heads.clone(), path.to_string());
            let atom = app
                .repos
                .read(&repo, move |r, cache| {
                    let projected = cache.load(r, &heads)?;
                    Ok(crate::repos::proposals::atom_at(&projected, &file, line).map(|(h, i)| (h.to_hex(), i)))
                })
                .await?
                .ok_or_else(|| ApiError(StatusCode::BAD_REQUEST, format!("{path}:{line} is not a line of the projected state")))?;
            Some((path.to_string(), atom))
        }
        _ => None,
    };
    let row_c = db::proposals::add_comment(
        &app.db,
        p.id,
        Some(me.id),
        &me.username,
        body.body.trim(),
        anchor.as_ref().map(|(path, _)| path.as_str()).unwrap_or(""),
        anchor.as_ref().map(|(_, (h, i))| (h.as_str(), *i as i64)),
    )
    .await?;
    crate::notify::deliver(
        &app,
        crate::notify::Event {
            kind: "proposal.comment",
            title: format!("{owner}/{name}#{number}: {}", p.title),
            url: format!("/{owner}/{name}/proposal/{number}"),
            actor: &me,
            repo_id: row.id,
            thread: Some(("proposal", p.id)),
            mention_text: &body.body,
            direct: p.author_id.into_iter().collect(),
        },
    )
    .await;
    crate::hooks::emit(
        &app,
        &row,
        "comment.proposal",
        &me.username,
        serde_json::json!({ "number": number, "comment": comment_of(&row_c) }),
    )
    .await;
    let mut created = comment_of(&row_c);
    created.line = created.anchor.as_ref().and(body.line);
    Ok((StatusCode::CREATED, Json(created)))
}

async fn proposal_reviews(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, number)): Path<(String, String, i64)>,
) -> Result<Json<Vec<Review>>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (repo, row, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let p = db::proposals::get(&app.db, row.id, number).await?.ok_or_else(|| not_found("no such proposal"))?;
    let loaded = crate::web::proposals::load_summary(&app, &repo, p).await?;
    let v = crate::web::proposals::verdict(&app, &loaded, row.id).await?;
    Ok(Json(
        v.reviews
            .into_iter()
            .map(|r| Review {
                id: r.row.id,
                author: r.row.author,
                verdict: r.row.verdict,
                body: r.row.body,
                sealed: r.sealed,
                created_ms: r.row.created_ms,
                via: r.row.via,
            })
            .collect(),
    ))
}

async fn proposal_review(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, number)): Path<(String, String, i64)>,
    Json(body): Json<NewReview>,
) -> Result<(StatusCode, Json<Review>), ApiError> {
    let c = caller(&app, &headers).await?;
    let me = c.require("proposals:write").or_else(|_| c.require("repo:write"))?.clone();
    let (_, row, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let p = db::proposals::get(&app.db, row.id, number).await?.ok_or_else(|| not_found("no such proposal"))?;
    if !matches!(body.verdict.as_str(), "comment" | "changes" | "approve") {
        return Err(ApiError(StatusCode::BAD_REQUEST, "verdict is comment, changes or approve".into()));
    }
    if body.verdict == "approve" && Some(me.id) == p.author_id {
        return Err(forbidden("you cannot approve your own proposal"));
    }
    let r = db::proposals::add_review(&app.db, p.id, me.id, &me.username, &body.verdict, body.body.trim()).await?;
    db::proposals::add_event(&app.db, p.id, &me.username, &format!("review.{}", body.verdict), "").await.ok();
    crate::web::proposals::reviewed(&app, &row, &p, &me, &body.verdict).await;
    crate::hooks::emit(&app, &row, "review", &me.username, serde_json::json!({ "number": number, "verdict": body.verdict })).await;
    Ok((
        StatusCode::CREATED,
        Json(Review { id: r.id, author: r.author, verdict: r.verdict, body: r.body, sealed: false, created_ms: r.created_ms, via: r.via }),
    ))
}

/// `POST .../proposals/{number}/reviewers`: ask accounts to review (the
/// author, or a writer). Answers with everyone asked now.
async fn request_reviewers(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, number)): Path<(String, String, i64)>,
    Json(body): Json<ReviewRequest>,
) -> Result<Json<Vec<String>>, ApiError> {
    let c = caller(&app, &headers).await?;
    let me = c.require("proposals:write").or_else(|_| c.require("repo:write"))?.clone();
    let (_, row, role) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let p = db::proposals::get(&app.db, row.id, number).await?.ok_or_else(|| not_found("no such proposal"))?;
    if Some(me.id) != p.author_id && role < Role::Write {
        return Err(forbidden("only the author or a writer asks for reviews"));
    }
    if !p.is_open() {
        return Err(ApiError(StatusCode::CONFLICT, "the proposal is not open".into()));
    }
    crate::web::proposals::request_reviewers(&app, &row, &p, &me, &body.reviewers)
        .await
        .map_err(|e| ApiError(StatusCode::UNPROCESSABLE_ENTITY, e))?;
    Ok(Json(db::proposals::review_requests(&app.db, p.id).await?))
}

/// `DELETE .../proposals/{number}/reviewers/{username}`: withdraw a request.
async fn withdraw_reviewer(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, number, username)): Path<(String, String, i64, String)>,
) -> Result<StatusCode, ApiError> {
    let c = caller(&app, &headers).await?;
    let me = c.require("proposals:write").or_else(|_| c.require("repo:write"))?.clone();
    let (_, row, role) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let p = db::proposals::get(&app.db, row.id, number).await?.ok_or_else(|| not_found("no such proposal"))?;
    if Some(me.id) != p.author_id && role < Role::Write {
        return Err(forbidden("only the author or a writer withdraws review requests"));
    }
    let a = db::accounts::account_by_name(&app.db, &username).await?.ok_or_else(|| not_found("no such account"))?;
    if db::proposals::unrequest_review(&app.db, p.id, a.id).await? {
        db::proposals::add_event(&app.db, p.id, &me.username, "review request withdrawn", &a.username).await.ok();
    }
    Ok(StatusCode::NO_CONTENT)
}

async fn proposal_checks(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, number)): Path<(String, String, i64)>,
) -> Result<Json<Vec<Check>>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (repo, row, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let p = db::proposals::get(&app.db, row.id, number).await?.ok_or_else(|| not_found("no such proposal"))?;
    let loaded = crate::web::proposals::load_summary(&app, &repo, p).await?;
    Ok(Json(db::hooks::checks_for_state(&app.db, row.id, &loaded.state).await?.iter().map(check_of).collect()))
}

// ------------------------------------------------------------------ issues

async fn issue_of(app: &Shared, row: &db::repos::RepoRow, i: &db::issues::IssueRow) -> Result<Issue, ApiError> {
    let labels = db::issues::issue_labels(&app.db, i.id)
        .await?
        .into_iter()
        .map(|l| Label { name: l.name, colour: l.colour, description: l.description })
        .collect();
    let assignees = db::issues::assignees(&app.db, i.id).await?;
    let milestone = match i.milestone_id {
        Some(id) => db::issues::milestone(&app.db, id).await?.map(|m| m.title),
        None => None,
    };
    let comments: i64 = sqlx::query_scalar("SELECT COUNT(*) FROM issue_comments WHERE issue_id = $1").bind(i.id).fetch_one(&app.db).await?;
    Ok(Issue {
        number: i.number,
        title: i.title.clone(),
        body: i.body.clone(),
        author: i.author.clone(),
        state: i.state.clone(),
        reason: i.reason.clone(),
        labels,
        assignees,
        milestone,
        comments,
        locked: i.locked,
        pinned: i.pinned,
        created_ms: i.created_ms,
        updated_ms: i.updated_ms,
        closed_ms: i.closed_ms,
        url: format!("{}/{}/issue/{}", app.config.base_url(), row.slug(), i.number),
    })
}

#[derive(Deserialize)]
struct IssuesQuery {
    state: Option<String>,
}

#[derive(Deserialize)]
struct ProposalsQuery {
    state: Option<String>,
    limit: Option<usize>,
}

async fn issues(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name)): Path<(String, String)>,
    Query(q): Query<IssuesQuery>,
) -> Result<Json<Vec<Issue>>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (_, row, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let state = q.state.unwrap_or_else(|| "open".into());
    let mut out = Vec::new();
    for i in db::issues::list(&app.db, row.id).await? {
        if state == "all" || i.state == state {
            out.push(issue_of(&app, &row, &i).await?);
        }
    }
    Ok(Json(out))
}

async fn create_issue(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name)): Path<(String, String)>,
    Json(body): Json<NewIssue>,
) -> Result<(StatusCode, Json<Issue>), ApiError> {
    let c = caller(&app, &headers).await?;
    let me = c.require("issues:write").or_else(|_| c.require("repo:write"))?.clone();
    let (_, row, role) = reach(&app, &c, &owner, &name, Access::Read).await?;
    if body.title.trim().is_empty() {
        return Err(ApiError(StatusCode::BAD_REQUEST, "an issue needs a title".into()));
    }
    let triage = !body.labels.is_empty() || !body.assignees.is_empty() || body.milestone.is_some();
    if triage && role < Role::Triage {
        return Err(forbidden("setting labels, assignees or a milestone needs triage access"));
    }
    // Check the names before anything is created.
    resolve_triage(&app, row.id, Some(&body.labels), Some(&body.assignees), body.milestone.as_deref()).await?;
    let i = db::issues::create(
        &app.db,
        db::issues::NewIssue {
            repo_id: row.id,
            title: body.title.trim(),
            body: body.body.trim(),
            author_id: Some(me.id),
            author: &me.username,
        },
    )
    .await?;
    db::issues::add_event(&app.db, i.id, &me.username, "opened", "").await.ok();
    if triage {
        let t = resolve_triage(&app, row.id, Some(&body.labels), Some(&body.assignees), body.milestone.as_deref()).await?;
        apply_triage(&app, &i, &me, t).await?;
    }
    let i = db::issues::get(&app.db, row.id, i.number).await?.unwrap_or(i);
    crate::web::issues::reindex(&app, row.id, &i).await;
    let api = issue_of(&app, &row, &i).await?;
    crate::notify::deliver(
        &app,
        crate::notify::Event {
            kind: "issue.opened",
            title: format!("{owner}/{name}#{}: {}", i.number, i.title),
            url: format!("/{owner}/{name}/issue/{}", i.number),
            actor: &me,
            repo_id: row.id,
            thread: Some(("issue", i.id)),
            mention_text: &body.body,
            direct: vec![],
        },
    )
    .await;
    crate::hooks::emit(&app, &row, "issue.opened", &me.username, serde_json::json!({ "issue": api })).await;
    Ok((StatusCode::CREATED, Json(api)))
}

async fn issue(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, number)): Path<(String, String, i64)>,
) -> Result<Json<Issue>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (_, row, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let i = db::issues::get(&app.db, row.id, number).await?.ok_or_else(|| not_found("no such issue"))?;
    Ok(Json(issue_of(&app, &row, &i).await?))
}

async fn issue_state(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, number)): Path<(String, String, i64)>,
    Json(body): Json<IssueStateChange>,
) -> Result<Json<Issue>, ApiError> {
    let c = caller(&app, &headers).await?;
    let me = c.require("issues:write").or_else(|_| c.require("repo:write"))?.clone();
    let (_, row, role) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let i = db::issues::get(&app.db, row.id, number).await?.ok_or_else(|| not_found("no such issue"))?;
    if role < Role::Triage && Some(me.id) != i.author_id {
        return Err(forbidden("only the author or triage may change the state"));
    }
    let (state, reason) = match body.state.as_str() {
        "closed" => ("closed", if body.reason == "not_planned" { "not_planned" } else { "completed" }),
        "open" => ("open", ""),
        _ => return Err(ApiError(StatusCode::BAD_REQUEST, "state is open or closed".into())),
    };
    db::issues::set_state(&app.db, i.id, state, reason).await?;
    db::issues::add_event(&app.db, i.id, &me.username, if state == "closed" { "closed" } else { "reopened" }, "").await.ok();
    let fresh = db::issues::get(&app.db, row.id, number).await?.unwrap_or(i);
    let api = issue_of(&app, &row, &fresh).await?;
    crate::hooks::emit(
        &app,
        &row,
        if state == "closed" { "issue.closed" } else { "issue.reopened" },
        &me.username,
        serde_json::json!({ "issue": api }),
    )
    .await;
    Ok(Json(api))
}

async fn issue_comments(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, number)): Path<(String, String, i64)>,
) -> Result<Json<Vec<Comment>>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (_, row, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let i = db::issues::get(&app.db, row.id, number).await?.ok_or_else(|| not_found("no such issue"))?;
    Ok(Json(
        db::issues::comments(&app.db, i.id)
            .await?
            .into_iter()
            .map(|c| Comment {
                id: c.id,
                author: c.author,
                body: c.body,
                created_ms: c.created_ms,
                path: None,
                anchor: None,
                line: None,
                resolved: false,
            })
            .collect(),
    ))
}

async fn issue_comment(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, number)): Path<(String, String, i64)>,
    Json(body): Json<NewComment>,
) -> Result<(StatusCode, Json<Comment>), ApiError> {
    let c = caller(&app, &headers).await?;
    let me = c.require("issues:write").or_else(|_| c.require("repo:write"))?.clone();
    let (_, row, role) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let i = db::issues::get(&app.db, row.id, number).await?.ok_or_else(|| not_found("no such issue"))?;
    if i.locked && role < Role::Triage {
        return Err(forbidden("this issue is locked"));
    }
    if body.body.trim().is_empty() {
        return Err(ApiError(StatusCode::BAD_REQUEST, "an empty comment says nothing".into()));
    }
    let cm = db::issues::add_comment(&app.db, i.id, Some(me.id), &me.username, body.body.trim()).await?;
    crate::web::issues::reindex(&app, row.id, &i).await;
    crate::notify::deliver(
        &app,
        crate::notify::Event {
            kind: "issue.comment",
            title: format!("{owner}/{name}#{number}: {}", i.title),
            url: format!("/{owner}/{name}/issue/{number}"),
            actor: &me,
            repo_id: row.id,
            thread: Some(("issue", i.id)),
            mention_text: &body.body,
            direct: i.author_id.into_iter().collect(),
        },
    )
    .await;
    let api = Comment {
        id: cm.id,
        author: cm.author,
        body: cm.body,
        created_ms: cm.created_ms,
        path: None,
        anchor: None,
        line: None,
        resolved: false,
    };
    crate::hooks::emit(&app, &row, "comment.issue", &me.username, serde_json::json!({ "number": number, "comment": api })).await;
    Ok((StatusCode::CREATED, Json(api)))
}

/// Labels, assignees and milestone named in a request, looked up.
struct Triage {
    labels: Option<Vec<db::issues::Label>>,
    assignees: Option<Vec<Account>>,
    /// `Some(None)` clears the milestone.
    milestone: Option<Option<db::issues::Milestone>>,
}

async fn resolve_triage(
    app: &Shared,
    repo_id: i64,
    labels: Option<&[String]>,
    assignees: Option<&[String]>,
    milestone: Option<&str>,
) -> Result<Triage, ApiError> {
    let bad = |m: String| ApiError(StatusCode::BAD_REQUEST, m);
    let labels = match labels {
        Some(names) => {
            let mut out = Vec::new();
            for n in names {
                out.push(
                    db::issues::label_by_name(&app.db, repo_id, n.trim())
                        .await?
                        .ok_or_else(|| bad(format!("no label {n:?}; create it first")))?,
                );
            }
            Some(out)
        }
        None => None,
    };
    let assignees = match assignees {
        Some(names) => {
            let mut out = Vec::new();
            for n in names {
                out.push(db::accounts::account_by_name(&app.db, n.trim()).await?.ok_or_else(|| bad(format!("no account {n:?}")))?);
            }
            Some(out)
        }
        None => None,
    };
    let milestone = match milestone.map(str::trim) {
        None => None,
        Some("") => Some(None),
        Some(title) => Some(Some(
            db::issues::milestones(&app.db, repo_id)
                .await?
                .into_iter()
                .find(|m| m.title == title)
                .ok_or_else(|| bad(format!("no milestone {title:?}")))?,
        )),
    };
    Ok(Triage { labels, assignees, milestone })
}

/// Make an issue's labels, assignees and milestone what `t` says, with
/// timeline events for what changed.
async fn apply_triage(app: &Shared, i: &db::issues::IssueRow, me: &Account, t: Triage) -> Result<(), ApiError> {
    if let Some(want) = t.labels {
        let have = db::issues::issue_labels(&app.db, i.id).await?;
        for l in &have {
            if !want.iter().any(|w| w.id == l.id) {
                db::issues::set_issue_label(&app.db, i.id, l.id, false).await?;
            }
        }
        for w in &want {
            if !have.iter().any(|l| l.id == w.id) {
                db::issues::set_issue_label(&app.db, i.id, w.id, true).await?;
            }
        }
        let names: Vec<&str> = want.iter().map(|l| l.name.as_str()).collect();
        db::issues::add_event(&app.db, i.id, &me.username, "set labels", &names.join(", ")).await.ok();
    }
    if let Some(want) = t.assignees {
        let have = db::issues::assignees(&app.db, i.id).await?;
        for name in &have {
            if !want.iter().any(|a| &a.username == name) {
                if let Some(a) = db::accounts::account_by_name(&app.db, name).await? {
                    db::issues::set_assignee(&app.db, i.id, a.id, false).await?;
                    db::issues::add_event(&app.db, i.id, &me.username, "unassigned", name).await.ok();
                }
            }
        }
        for a in &want {
            if !have.contains(&a.username) {
                db::issues::set_assignee(&app.db, i.id, a.id, true).await?;
                db::issues::add_event(&app.db, i.id, &me.username, "assigned", &a.username).await.ok();
            }
        }
    }
    if let Some(m) = t.milestone {
        db::issues::set_milestone(&app.db, i.id, m.as_ref().map(|m| m.id)).await?;
        db::issues::add_event(&app.db, i.id, &me.username, "set milestone", m.as_ref().map(|m| m.title.as_str()).unwrap_or("")).await.ok();
    }
    Ok(())
}

/// `PATCH /repos/{o}/{n}/issues/{number}`.
async fn issue_edit(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, number)): Path<(String, String, i64)>,
    Json(body): Json<IssueEdit>,
) -> Result<Json<Issue>, ApiError> {
    let c = caller(&app, &headers).await?;
    let me = c.require("issues:write").or_else(|_| c.require("repo:write"))?.clone();
    let (_, row, role) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let i = db::issues::get(&app.db, row.id, number).await?.ok_or_else(|| not_found("no such issue"))?;
    let text = body.title.is_some() || body.body.is_some();
    let triage = body.labels.is_some() || body.assignees.is_some() || body.milestone.is_some();
    if text && role < Role::Triage && Some(me.id) != i.author_id {
        return Err(forbidden("only the author or triage may edit the title and body"));
    }
    if triage && role < Role::Triage {
        return Err(forbidden("setting labels, assignees or a milestone needs triage access"));
    }
    if i.locked && role < Role::Triage {
        return Err(forbidden("this issue is locked"));
    }
    let t = resolve_triage(&app, row.id, body.labels.as_deref(), body.assignees.as_deref(), body.milestone.as_deref()).await?;
    if text {
        let title = body.title.as_deref().map(str::trim).unwrap_or(&i.title);
        if title.is_empty() {
            return Err(ApiError(StatusCode::BAD_REQUEST, "an issue needs a title".into()));
        }
        db::issues::edit(&app.db, i.id, title, body.body.as_deref().unwrap_or(&i.body)).await?;
        db::issues::add_event(&app.db, i.id, &me.username, "edited", "").await.ok();
    }
    apply_triage(&app, &i, &me, t).await?;
    db::issues::touch(&app.db, i.id).await.ok();
    let fresh = db::issues::get(&app.db, row.id, number).await?.unwrap_or(i);
    crate::web::issues::reindex(&app, row.id, &fresh).await;
    let api = issue_of(&app, &row, &fresh).await?;
    crate::hooks::emit(&app, &row, "issue.edited", &me.username, serde_json::json!({ "issue": api })).await;
    Ok(Json(api))
}

/// `POST /repos/{o}/{n}/labels` (triage).
async fn create_label(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name)): Path<(String, String)>,
    Json(body): Json<NewLabel>,
) -> Result<(StatusCode, Json<Label>), ApiError> {
    let c = caller(&app, &headers).await?;
    c.require("issues:write").or_else(|_| c.require("repo:write"))?;
    let (_, row, role) = reach(&app, &c, &owner, &name, Access::Read).await?;
    if role < Role::Triage {
        return Err(forbidden("labels need triage access"));
    }
    let label = body.name.trim();
    if label.is_empty() || label.len() > 50 {
        return Err(ApiError(StatusCode::BAD_REQUEST, "a label has a name of 1 to 50 characters".into()));
    }
    let colour = match body.colour.as_deref() {
        Some(c) if c.len() == 7 && c.starts_with('#') && c[1..].chars().all(|x| x.is_ascii_hexdigit()) => c.to_string(),
        Some(c) => return Err(ApiError(StatusCode::BAD_REQUEST, format!("colour {c:?} is not #rrggbb"))),
        None => "#5aa8ff".to_string(),
    };
    let l = db::issues::upsert_label(&app.db, row.id, label, &colour, body.description.trim()).await?;
    Ok((StatusCode::CREATED, Json(Label { name: l.name, colour: l.colour, description: l.description })))
}

/// `DELETE /repos/{o}/{n}/labels/{label}` (triage).
async fn delete_label(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, label)): Path<(String, String, String)>,
) -> Result<StatusCode, ApiError> {
    let c = caller(&app, &headers).await?;
    c.require("issues:write").or_else(|_| c.require("repo:write"))?;
    let (_, row, role) = reach(&app, &c, &owner, &name, Access::Read).await?;
    if role < Role::Triage {
        return Err(forbidden("labels need triage access"));
    }
    let l = db::issues::label_by_name(&app.db, row.id, &label).await?.ok_or_else(|| not_found("no such label"))?;
    db::issues::delete_label(&app.db, l.id).await?;
    Ok(StatusCode::NO_CONTENT)
}

async fn labels(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name)): Path<(String, String)>,
) -> Result<Json<Vec<Label>>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (_, row, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    Ok(Json(
        db::issues::labels(&app.db, row.id)
            .await?
            .into_iter()
            .map(|l| Label { name: l.name, colour: l.colour, description: l.description })
            .collect(),
    ))
}

async fn milestones(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name)): Path<(String, String)>,
) -> Result<Json<Vec<Milestone>>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (_, row, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let mut out = Vec::new();
    for m in db::issues::milestones(&app.db, row.id).await? {
        let (open, closed) = db::issues::milestone_counts(&app.db, m.id).await?;
        out.push(Milestone { title: m.title, description: m.description, due_ms: m.due_ms, state: m.state, open, closed });
    }
    Ok(Json(out))
}

fn milestone_of(m: db::issues::Milestone, open: i64, closed: i64) -> Milestone {
    Milestone { title: m.title, description: m.description, due_ms: m.due_ms, state: m.state, open, closed }
}

/// A due date as `YYYY-MM-DD` (UTC midnight), or the empty string for none.
fn due_ms_of(due: &str) -> Result<Option<i64>, ApiError> {
    let due = due.trim();
    if due.is_empty() {
        return Ok(None);
    }
    time::Date::parse(due, &time::macros::format_description!("[year]-[month]-[day]"))
        .map(|d| Some(d.midnight().assume_utc().unix_timestamp() * 1000))
        .map_err(|_| ApiError(StatusCode::BAD_REQUEST, format!("due {due:?} is not YYYY-MM-DD")))
}

async fn triage_for_milestones(app: &Shared, headers: &HeaderMap, owner: &str, name: &str) -> Result<db::repos::RepoRow, ApiError> {
    let c = caller(app, headers).await?;
    c.require("issues:write").or_else(|_| c.require("repo:write"))?;
    let (_, row, role) = reach(app, &c, owner, name, Access::Read).await?;
    if role < Role::Triage {
        return Err(forbidden("milestones need triage access"));
    }
    Ok(row)
}

/// `POST /repos/{o}/{n}/milestones` (triage, oxygenhub#91): create a
/// milestone, or change the description and due date of the one with
/// that title.
async fn create_milestone(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name)): Path<(String, String)>,
    Json(body): Json<NewMilestone>,
) -> Result<(StatusCode, Json<Milestone>), ApiError> {
    let row = triage_for_milestones(&app, &headers, &owner, &name).await?;
    let title = body.title.trim();
    if title.is_empty() || title.len() > 100 {
        return Err(ApiError(StatusCode::BAD_REQUEST, "a milestone has a title of 1 to 100 characters".into()));
    }
    let due_ms = due_ms_of(body.due.as_deref().unwrap_or(""))?;
    let m = db::issues::upsert_milestone(&app.db, row.id, title, body.description.trim(), due_ms).await?;
    let (open, closed) = db::issues::milestone_counts(&app.db, m.id).await?;
    Ok((StatusCode::CREATED, Json(milestone_of(m, open, closed))))
}

/// `PATCH /repos/{o}/{n}/milestones/{title}` (triage): title,
/// description, due date and state; what is not given stays.
async fn edit_milestone(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, title)): Path<(String, String, String)>,
    Json(body): Json<MilestoneEdit>,
) -> Result<Json<Milestone>, ApiError> {
    let row = triage_for_milestones(&app, &headers, &owner, &name).await?;
    let m = db::issues::milestones(&app.db, row.id)
        .await?
        .into_iter()
        .find(|m| m.title == title)
        .ok_or_else(|| not_found("no such milestone"))?;
    let new_title = body.title.as_deref().map(str::trim).unwrap_or(&m.title);
    if new_title.is_empty() || new_title.len() > 100 {
        return Err(ApiError(StatusCode::BAD_REQUEST, "a milestone has a title of 1 to 100 characters".into()));
    }
    let due_ms = match body.due.as_deref() {
        Some(d) => due_ms_of(d)?,
        None => m.due_ms,
    };
    let description = body.description.as_deref().map(str::trim).unwrap_or(&m.description);
    if body.title.is_some() || body.description.is_some() || body.due.is_some() {
        db::issues::update_milestone(&app.db, m.id, new_title, description, due_ms).await?;
    }
    if let Some(state) = body.state.as_deref() {
        match state {
            "open" | "closed" => db::issues::set_milestone_state(&app.db, m.id, state).await?,
            other => return Err(ApiError(StatusCode::BAD_REQUEST, format!("state {other:?} is open or closed"))),
        }
    }
    let fresh = db::issues::milestone(&app.db, m.id).await?.ok_or_else(|| not_found("no such milestone"))?;
    let (open, closed) = db::issues::milestone_counts(&app.db, fresh.id).await?;
    Ok(Json(milestone_of(fresh, open, closed)))
}

// --------------------------------------------------------- hooks, checks

fn hook_of(h: &db::hooks::Hook) -> Hook {
    Hook { id: h.id, url: h.url.clone(), events: h.events.clone(), active: h.active, created_ms: h.created_ms }
}

async fn hooks(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name)): Path<(String, String)>,
) -> Result<Json<Vec<Hook>>, ApiError> {
    let c = caller(&app, &headers).await?;
    c.require("hooks:admin").or_else(|_| c.require("repo:admin"))?;
    let (_, row, _) = reach(&app, &c, &owner, &name, Access::Admin).await?;
    Ok(Json(db::hooks::hooks_for_repo(&app.db, row.id).await?.iter().map(hook_of).collect()))
}

async fn create_hook(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name)): Path<(String, String)>,
    Json(body): Json<NewHook>,
) -> Result<(StatusCode, Json<Hook>), ApiError> {
    let c = caller(&app, &headers).await?;
    let me = c.require("hooks:admin").or_else(|_| c.require("repo:admin"))?.clone();
    let (_, row, _) = reach(&app, &c, &owner, &name, Access::Admin).await?;
    if !(body.url.starts_with("http://") || body.url.starts_with("https://")) {
        return Err(ApiError(StatusCode::BAD_REQUEST, "the URL must be http or https".into()));
    }
    let h = db::hooks::create_hook(&app.db, Some(row.id), None, &body.url, &body.secret, &body.events).await?;
    db::accounts::audit(&app.db, Some(&me), "hook.created", &row.slug(), &body.url).await.ok();
    Ok((StatusCode::CREATED, Json(hook_of(&h))))
}

async fn delete_hook(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, id)): Path<(String, String, i64)>,
) -> Result<StatusCode, ApiError> {
    let c = caller(&app, &headers).await?;
    c.require("hooks:admin").or_else(|_| c.require("repo:admin"))?;
    let (_, row, _) = reach(&app, &c, &owner, &name, Access::Admin).await?;
    if db::hooks::hook(&app.db, id).await?.is_some_and(|h| h.repo_id == Some(row.id)) {
        db::hooks::delete_hook(&app.db, id).await?;
    }
    Ok(StatusCode::NO_CONTENT)
}

pub fn check_of(c: &db::hooks::Check) -> Check {
    Check {
        state: c.state.clone(),
        name: c.name.clone(),
        status: CheckStatus::parse(&c.status).unwrap_or(CheckStatus::Queued),
        summary: c.summary.clone(),
        url: c.url.clone(),
        reporter: c.reporter.clone(),
        seal: if c.seal.is_empty() { None } else { Some(c.seal.clone()) },
        started_ms: c.started_ms,
        finished_ms: c.finished_ms,
    }
}

/// `GET /repos/{o}/{n}/checks/required`.
async fn required_checks(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name)): Path<(String, String)>,
) -> Result<Json<RequiredChecks>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (_, row, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    Ok(Json(RequiredChecks { names: db::hooks::required_checks(&app.db, row.id).await? }))
}

/// `PUT /repos/{o}/{n}/checks/required` (repository admin): the whole list.
async fn set_required_checks(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name)): Path<(String, String)>,
    Json(body): Json<RequiredChecks>,
) -> Result<Json<RequiredChecks>, ApiError> {
    let c = caller(&app, &headers).await?;
    c.require("repo:admin")?;
    let (_, row, _) = reach(&app, &c, &owner, &name, Access::Admin).await?;
    let mut names: Vec<String> = body.names.iter().map(|n| n.trim().to_string()).filter(|n| !n.is_empty()).collect();
    names.sort();
    names.dedup();
    if names.len() > 32 || names.iter().any(|n| n.len() > 100 || n.contains(',')) {
        return Err(ApiError(StatusCode::BAD_REQUEST, "at most 32 check names, each under 100 characters and without commas".into()));
    }
    db::hooks::set_required_checks(&app.db, row.id, &names).await?;
    db::accounts::audit(&app.db, c.account.as_ref(), "repo.required_checks", &format!("{owner}/{name}"), &names.join(", ")).await.ok();
    Ok(Json(RequiredChecks { names }))
}

fn flow_run_of(
    app: &Shared,
    row: &db::repos::RepoRow,
    r: &db::flow::Run,
    jobs: Vec<db::flow::Job>,
    queue: &[db::flow::QueueEntry],
) -> FlowRun {
    FlowRun {
        queue_position: crate::flow::queue_info(queue, row.id, r.id).position.map(|p| p as i64),
        number: r.number,
        bookmark: r.bookmark.clone(),
        state: r.state.clone(),
        heads: r.head_list().into_iter().map(String::from).collect(),
        status: r.status.clone(),
        trigger: r.trigger_label(),
        actor: r.actor.clone(),
        pipeline_hash: r.pipeline_hash.clone(),
        error: r.error.clone(),
        created_ms: r.created_ms,
        finished_ms: r.finished_ms,
        url: format!("{}/{}/{}/flow/{}", app.config.base_url(), row.owner, row.name, r.number),
        jobs: jobs
            .into_iter()
            .map(|j| FlowJob {
                depends_on: j.depends_on(),
                name: j.name,
                status: j.status,
                runner: j.runner,
                exit_code: j.exit_code,
                error: j.error,
                started_ms: j.started_ms,
                finished_ms: j.finished_ms,
                log_lines: j.log_count,
                waiting: j.waiting,
                placed: j.placed,
            })
            .collect(),
    }
}

#[derive(Deserialize)]
struct RunsPage {
    /// Runs numbered below this one (the next page).
    before: Option<i64>,
    limit: Option<i64>,
}

/// `GET /repos/{o}/{n}/flow/runs`: newest first, `?before=N&limit=` (max 100).
async fn flow_runs(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name)): Path<(String, String)>,
    Query(q): Query<RunsPage>,
) -> Result<Json<Vec<FlowRun>>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (_, row, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let limit = q.limit.unwrap_or(30).clamp(1, 100);
    let runs = db::flow::runs_by_number(&app.db, row.id, limit, q.before).await?;
    let queue = if runs.iter().any(|r| r.live()) { db::flow::queue(&app.db).await? } else { vec![] };
    Ok(Json(runs.iter().map(|r| flow_run_of(&app, &row, r, vec![], &queue)).collect()))
}

/// `GET /repos/{o}/{n}/flow/runs/{number}`: a run with its jobs.
async fn flow_run(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, number)): Path<(String, String, i64)>,
) -> Result<Json<FlowRun>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (_, row, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let run = db::flow::run(&app.db, row.id, number).await?.ok_or_else(|| ApiError(StatusCode::NOT_FOUND, "no such run".into()))?;
    let jobs = db::flow::jobs(&app.db, run.id).await?;
    let queue = if run.live() { db::flow::queue(&app.db).await? } else { vec![] };
    Ok(Json(flow_run_of(&app, &row, &run, jobs, &queue)))
}

#[derive(Deserialize)]
struct LogPage {
    /// Lines after this `seq`.
    #[serde(default)]
    after: i64,
    limit: Option<i64>,
}

/// `GET /repos/{o}/{n}/flow/runs/{number}/jobs/{job}/log`: `?after=seq&limit=` (max 5000).
async fn flow_job_log(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, number, job)): Path<(String, String, i64, String)>,
    Query(q): Query<LogPage>,
) -> Result<Json<Vec<FlowLogLine>>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (_, row, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let run = db::flow::run(&app.db, row.id, number).await?.ok_or_else(|| ApiError(StatusCode::NOT_FOUND, "no such run".into()))?;
    let j = db::flow::jobs(&app.db, run.id)
        .await?
        .into_iter()
        .find(|j| j.name == job)
        .ok_or_else(|| ApiError(StatusCode::NOT_FOUND, "no such job".into()))?;
    let lines = db::flow::log(&app.db, j.id, q.after, q.limit.unwrap_or(1000).clamp(1, 5000)).await?;
    Ok(Json(lines.into_iter().map(|l| FlowLogLine { seq: l.seq, t: l.t, stream: l.stream, text: l.text }).collect()))
}

#[derive(Deserialize)]
struct StartRun {
    /// Default: the repository's default bookmark.
    #[serde(default)]
    bookmark: Option<String>,
    /// A change's full hash: run the state whose only head it is, instead
    /// of a bookmark's.
    #[serde(default)]
    change: Option<String>,
    /// Only these jobs, with what they depend on (oxygenhub#130); default:
    /// every job a manual run starts.
    #[serde(default)]
    jobs: Vec<String>,
}

fn started(app: &Shared, row: &db::repos::RepoRow, number: i64) -> (StatusCode, Json<serde_json::Value>) {
    let url = format!("{}/{}/{}/flow/{number}", app.config.base_url(), row.owner, row.name);
    (StatusCode::CREATED, Json(serde_json::json!({ "number": number, "url": url })))
}

/// `POST /repos/{o}/{n}/flow/runs` (repo:write): run a bookmark's current
/// state, or one change's, without moving anything (hub spec §13.2).
async fn start_flow_run(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name)): Path<(String, String)>,
    Json(body): Json<StartRun>,
) -> Result<(StatusCode, Json<serde_json::Value>), ApiError> {
    let c = caller(&app, &headers).await?;
    let me = c.require("repo:write")?.clone();
    let (_, row, _) = reach(&app, &c, &owner, &name, Access::Write).await?;
    let (n, what) = match body.change.clone().filter(|c| !c.trim().is_empty()) {
        Some(change) => {
            let n = crate::flow::run_change(&app, &row, &change, &me.username, &body.jobs)
                .await
                .map_err(|m| ApiError(StatusCode::CONFLICT, m))?;
            (n, format!("change {}", change.trim()))
        }
        None => {
            let bookmark = body.bookmark.unwrap_or_else(|| row.default_bookmark.clone());
            (
                crate::flow::run_bookmark(&app, &row, &bookmark, &me.username, &body.jobs)
                    .await
                    .map_err(|m| ApiError(StatusCode::CONFLICT, m))?,
                bookmark,
            )
        }
    };
    db::accounts::audit(&app.db, Some(&me), "flow.run", &format!("{owner}/{name}"), &format!("#{n} {what}")).await.ok();
    Ok(started(&app, &row, n))
}

/// `POST /repos/{o}/{n}/flow/runs/{number}/rerun` (repo:write).
async fn rerun_flow_run(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, number)): Path<(String, String, i64)>,
) -> Result<(StatusCode, Json<serde_json::Value>), ApiError> {
    let c = caller(&app, &headers).await?;
    let me = c.require("repo:write")?.clone();
    let (_, row, _) = reach(&app, &c, &owner, &name, Access::Write).await?;
    let run = db::flow::run(&app.db, row.id, number).await?.ok_or_else(|| ApiError(StatusCode::NOT_FOUND, "no such run".into()))?;
    let n = crate::flow::rerun(&app, &row, &run, &me.username).await.map_err(|m| ApiError(StatusCode::CONFLICT, m))?;
    db::accounts::audit(&app.db, Some(&me), "flow.rerun", &format!("{owner}/{name}"), &format!("#{n} of #{number}")).await.ok();
    Ok(started(&app, &row, n))
}

/// `POST /repos/{o}/{n}/flow/runs/{number}/jobs/{job}/rerun` (repo:write,
/// oxygenflow#31): that job again, with the jobs that depend on it, in the
/// same run. Answers with how many jobs were queued.
async fn rerun_flow_job(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, number, job)): Path<(String, String, i64, String)>,
) -> Result<Json<serde_json::Value>, ApiError> {
    let c = caller(&app, &headers).await?;
    let me = c.require("repo:write")?.clone();
    let (_, row, _) = reach(&app, &c, &owner, &name, Access::Write).await?;
    let run = db::flow::run(&app.db, row.id, number).await?.ok_or_else(|| ApiError(StatusCode::NOT_FOUND, "no such run".into()))?;
    let n = crate::flow::rerun_job(&app, &row, &run, &job, &me.username).await.map_err(|m| ApiError(StatusCode::CONFLICT, m))?;
    db::accounts::audit(&app.db, Some(&me), "flow.rerun", &format!("{owner}/{name}"), &format!("{job} of #{number}")).await.ok();
    Ok(Json(serde_json::json!({ "run": number, "job": job, "queued": n })))
}

/// `POST /repos/{o}/{n}/flow/runs/{number}/cancel` (repo:write): answers
/// with the run as it now stands.
async fn cancel_flow_run(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, number)): Path<(String, String, i64)>,
) -> Result<Json<serde_json::Value>, ApiError> {
    let c = caller(&app, &headers).await?;
    let me = c.require("repo:write")?.clone();
    let (_, row, _) = reach(&app, &c, &owner, &name, Access::Write).await?;
    let run = db::flow::run(&app.db, row.id, number).await?.ok_or_else(|| ApiError(StatusCode::NOT_FOUND, "no such run".into()))?;
    crate::flow::cancel(&app, &row, &run, &me.username).await.map_err(|m| ApiError(StatusCode::CONFLICT, m))?;
    db::accounts::audit(&app.db, Some(&me), "flow.cancel", &format!("{owner}/{name}"), &format!("#{number}")).await.ok();
    Ok(Json(serde_json::json!({ "number": number, "status": "cancelled" })))
}

/// `GET /repos/{o}/{n}/deployments`: deployments, newest first
/// (oxygenflow#59).
async fn list_deployments(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name)): Path<(String, String)>,
) -> Result<Json<Vec<serde_json::Value>>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (_, row, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let list = db::flow::deployments(&app.db, row.id, 100).await?;
    Ok(Json(
        list.into_iter()
            .map(|d| {
                serde_json::json!({ "environment": d.environment, "job": d.job, "run": d.run_number, "state": d.state,
                    "bookmark": d.bookmark, "actor": d.actor, "approved_by": d.approved_by, "finished_ms": d.finished_ms })
            })
            .collect(),
    ))
}

/// `POST /repos/{o}/{n}/flow/runs/{number}/jobs/{job}/approve` and
/// `.../reject` (oxygenflow#57): the job's approval rules decide who may.
async fn approve_flow_job(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, number, job)): Path<(String, String, i64, String)>,
) -> Result<Json<serde_json::Value>, ApiError> {
    decide_flow_job(&app, &headers, &owner, &name, number, &job, true).await
}

async fn reject_flow_job(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, number, job)): Path<(String, String, i64, String)>,
) -> Result<Json<serde_json::Value>, ApiError> {
    decide_flow_job(&app, &headers, &owner, &name, number, &job, false).await
}

/// `GET .../flow/runs/{n}/jobs/{job}/approval`: what approving the job
/// means, for `oxy seal --flow` to sign (oxygenhub#235).
async fn flow_job_statement(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, number, job)): Path<(String, String, i64, String)>,
) -> Result<Json<serde_json::Value>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (_, row, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let run = db::flow::run(&app.db, row.id, number).await?.ok_or_else(|| ApiError(StatusCode::NOT_FOUND, "no such run".into()))?;
    let (s, j) = crate::flow::approval_statement(&app, &row, &run, &job).await.map_err(|m| ApiError(StatusCode::CONFLICT, m))?;
    Ok(Json(serde_json::json!({
        "repo": hex::encode(s.repo),
        "run": s.run,
        "job": s.job,
        "job_hash": s.job_hash.to_hex(),
        "state": s.state.to_hex(),
        "inputs": s.inputs.iter().map(|i| i.to_hex()).collect::<Vec<_>>(),
        "environment": s.environment,
        "waiting": j.approval == "waiting" && j.status == "queued",
    })))
}

#[derive(Deserialize)]
struct SealBody {
    signed: String,
}

/// `POST .../flow/runs/{n}/jobs/{job}/seal` `{"signed": hex}`: approve or
/// reject with a signed approval (oxygenhub#235). The signature, not the
/// caller, says who decided; the caller must be signed in.
async fn seal_flow_job(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, number, job)): Path<(String, String, i64, String)>,
    Json(body): Json<SealBody>,
) -> Result<Json<serde_json::Value>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (_, row, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let run = db::flow::run(&app.db, row.id, number).await?.ok_or_else(|| ApiError(StatusCode::NOT_FOUND, "no such run".into()))?;
    let said = crate::flow::decide_sealed(&app, &row, &run, &job, &body.signed).await.map_err(|m| ApiError(StatusCode::CONFLICT, m))?;
    Ok(Json(serde_json::json!({ "number": number, "job": job, "said": said })))
}

async fn decide_flow_job(
    app: &Shared,
    headers: &HeaderMap,
    owner: &str,
    name: &str,
    number: i64,
    job: &str,
    approve: bool,
) -> Result<Json<serde_json::Value>, ApiError> {
    let c = caller(app, headers).await?;
    let me = c.require("repo:write")?.clone();
    let (_, row, _) = reach(app, &c, owner, name, Access::Read).await?;
    let run = db::flow::run(&app.db, row.id, number).await?.ok_or_else(|| ApiError(StatusCode::NOT_FOUND, "no such run".into()))?;
    let via = c.agent.then_some(c.token.as_str());
    let said = crate::flow::decide(app, &row, &run, job, &me, approve, via).await.map_err(|m| ApiError(StatusCode::CONFLICT, m))?;
    Ok(Json(serde_json::json!({ "number": number, "job": job, "decision": if approve { "approved" } else { "rejected" }, "said": said })))
}

/// `POST /repos/{o}/{n}/checks`: any `checks:write` (or write) token may
/// report; the state hash names what was checked.
async fn post_check(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name)): Path<(String, String)>,
    Json(body): Json<NewCheck>,
) -> Result<(StatusCode, Json<Check>), ApiError> {
    let c = caller(&app, &headers).await?;
    let me = c.require("checks:write").or_else(|_| c.require("repo:write"))?.clone();
    let (_, row, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    if body.state.len() != 64 || !body.state.chars().all(|ch| ch.is_ascii_hexdigit()) {
        return Err(ApiError(StatusCode::BAD_REQUEST, "state is a 64-character hex state hash".into()));
    }
    if body.name.trim().is_empty() || body.name.len() > 100 {
        return Err(ApiError(StatusCode::BAD_REQUEST, "a check has a short name".into()));
    }
    let ch = db::hooks::upsert_check(
        &app.db,
        row.id,
        &body.state,
        body.name.trim(),
        body.status.as_str(),
        &body.summary,
        &body.url,
        Some((me.id, &me.username)),
        body.seal.as_deref().unwrap_or(""),
    )
    .await?;
    let api = check_of(&ch);
    app.bus.proposal(row.id, ProposalEvent { number: 0, kind: "check".into(), check: Some(api.clone()) });
    crate::hooks::emit(&app, &row, "check", &me.username, serde_json::json!({ "check": api })).await;
    Ok((StatusCode::CREATED, Json(api)))
}

async fn checks_for_state(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, state)): Path<(String, String, String)>,
) -> Result<Json<Vec<Check>>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (repo, row, _) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let state = state_key(&app, &repo, &state).await?;
    Ok(Json(db::hooks::checks_for_state(&app.db, row.id, &state).await?.iter().map(check_of).collect()))
}

/// The state hash checks are keyed by, from what a client has: a state
/// hash, its heads (full change hashes joined with `+`, or the one head of
/// a single-head state, which is what `oxy log` shows), or a bookmark.
async fn state_key(app: &Shared, repo: &RepoName, s: &str) -> Result<String, ApiError> {
    use oxy_core::hash::{hash_object, ChangeHash, ObjectType};
    let hexes: Vec<&str> = s.split('+').collect();
    let all_hashes = hexes.iter().all(|h| h.len() == 64 && h.bytes().all(|b| b.is_ascii_hexdigit()));
    if all_hashes {
        let row = db::repos::get(&app.db, &repo.owner, &repo.name).await?.ok_or_else(|| not_found("no such repository"))?;
        if hexes.len() == 1 && !db::hooks::checks_for_state(&app.db, row.id, s).await?.is_empty() {
            return Ok(s.to_string());
        }
        let heads: Vec<ChangeHash> = hexes.iter().filter_map(|h| ChangeHash::from_hex(h)).collect();
        return Ok(hash_object(ObjectType::State, &oxy_core::objects::StateObject::new(heads).encode()).to_hex());
    }
    let b = s.to_string();
    let found = app.repos.read(repo, move |r, _| Ok(r.view()?.bookmarks.get(&b).copied())).await?;
    found.map(|st| st.to_hex()).ok_or_else(|| ApiError(StatusCode::NOT_FOUND, format!("{s:?} is not a state hash, heads or a bookmark")))
}

// ----------------------------------------------------------------- runners

/// Site administrators only, with any token of theirs (hub spec §13.2).
fn require_site_admin(c: &Caller) -> Result<&Account, ApiError> {
    match c.account.as_ref() {
        Some(a) if a.is_admin => Ok(a),
        _ => Err(not_found("no such API route")),
    }
}

/// `GET /api/v1/admin/runner-updates` (oxygenhub#322, #326).
async fn runner_updates(State(app): State<Shared>, headers: HeaderMap) -> Result<Json<RunnerUpdates>, ApiError> {
    let c = caller(&app, &headers).await?;
    require_site_admin(&c)?;
    use crate::web::runner_updates::{views, Reach};
    let v = views(&app, &Reach::Site).await?;
    let setting = |p: &crate::web::runner_updates::PolicyView| UpdateSetting {
        scope: p.scope.clone(),
        key: p.key.clone(),
        updates: match p.updates {
            "on" => Some(true),
            "off" => Some(false),
            _ => None,
        },
        channel: Some(p.channel.clone()).filter(|c| !c.is_empty()),
        window: Some(p.window.clone()).filter(|w| !w.is_empty()),
        dry_run: match p.dry_run {
            "on" => Some(true),
            "off" => Some(false),
            _ => None,
        },
    };
    let mut settings = vec![setting(&v.site)];
    settings.extend(v.owners.iter().map(setting));
    settings.extend(v.groups.iter().map(|g| setting(&g.policy)));
    settings.extend(v.runners.iter().map(|r| setting(&r.policy)));
    settings.retain(|s| s.scope == "site" || s.updates.is_some() || s.channel.is_some() || s.window.is_some() || s.dry_run.is_some());
    Ok(Json(RunnerUpdates {
        repo: db::accounts::setting(&app.db, crate::runner_updates::SETTING_REPO).await?.unwrap_or_default(),
        settings,
        groups: v
            .groups
            .iter()
            .map(|g| RunnerGroup {
                id: g.g.id,
                owner: g.g.owner.clone(),
                name: g.g.name.clone(),
                percent: g.g.percent,
                members: g.members.clone(),
            })
            .collect(),
        runners: v
            .runners
            .iter()
            .map(|r| RunnerUpdate {
                id: r.r.id,
                name: r.r.name.clone(),
                owner: r.r.scope_owner.clone(),
                version: r.r.version.clone(),
                groups: r.groups.clone(),
                updates: r.effective.updates,
                channel: r.effective.channel.clone(),
                window: r.effective.window.map(|(a, b)| format!("{a:02}-{b:02}")),
                dry_run: r.effective.dry_run,
                from: r.effective.from.clone(),
                now: r.offer.clone(),
                said: r.r.update_note.clone(),
            })
            .collect(),
        holds: db::runner_updates::holds(&app.db)
            .await?
            .into_iter()
            .map(|h| HeldBuild { version: h.version, runner: h.runner, why: h.why, at_ms: h.at_ms })
            .collect(),
    }))
}

/// `PUT /api/v1/admin/runner-updates/settings`: one level's settings; what
/// it set, in words, or 422 saying what is wrong.
async fn runner_update_setting(
    State(app): State<Shared>,
    headers: HeaderMap,
    Json(u): Json<UpdateSetting>,
) -> Result<Json<serde_json::Value>, ApiError> {
    let c = caller(&app, &headers).await?;
    let me = require_site_admin(&c)?.clone();
    use crate::web::runner_updates::{apply_policy, PolicyForm, Reach};
    match apply_policy(&app, &me, &Reach::Site, &PolicyForm::of(&u)).await? {
        Ok(notice) => Ok(Json(serde_json::json!({ "notice": notice }))),
        Err(why) => Err(ApiError(StatusCode::UNPROCESSABLE_ENTITY, why)),
    }
}

/// `POST /api/v1/admin/runner-updates/holds/{version}/lift` (#326).
async fn runner_update_lift(State(app): State<Shared>, headers: HeaderMap, Path(version): Path<String>) -> Result<StatusCode, ApiError> {
    let c = caller(&app, &headers).await?;
    let me = require_site_admin(&c)?.clone();
    if !db::runner_updates::lift(&app.db, &version).await? {
        return Err(not_found("that build is not held"));
    }
    db::accounts::audit(&app.db, Some(&me), "runner.update.lifted", &version, "offered again").await.ok();
    Ok(StatusCode::NO_CONTENT)
}

async fn runner_of(app: &Shared, r: db::runners::Runner, running: i64) -> hub_api::Runner {
    let serves = match r.scope_repo_id {
        Some(id) => db::repos::get_by_id(&app.db, id).await.ok().flatten().map(|p| p.slug()).unwrap_or_default(),
        None => r.scope_owner.clone(),
    };
    hub_api::Runner {
        id: r.id,
        status: r.status().to_string(),
        serves,
        labels: r.label_list().into_iter().map(String::from).collect(),
        name: r.name,
        arch: r.arch,
        os: r.os,
        version: r.version,
        max_jobs: r.max_jobs,
        memory_mib: r.memory_mib,
        cpus: r.cpus,
        key: r.key,
        source: r.source,
        last_seen_ms: r.last_seen_ms,
        running,
        free_disk_mib: r.free_disk_mib,
        load_x100: r.load_x100,
        speed: r.speed,
        speed_class: r.speed_class,
        kernel: r.kernel,
    }
}

/// `GET /api/v1/runners`.
async fn runners(State(app): State<Shared>, headers: HeaderMap) -> Result<Json<Vec<hub_api::Runner>>, ApiError> {
    let c = caller(&app, &headers).await?;
    require_site_admin(&c)?;
    let running: std::collections::HashMap<i64, i64> = db::runners::running(&app.db).await?.into_iter().collect();
    let mut out = Vec::new();
    for r in db::runners::list(&app.db).await? {
        let n = running.get(&r.id).copied().unwrap_or(0);
        out.push(runner_of(&app, r, n).await);
    }
    Ok(Json(out))
}

#[derive(Deserialize)]
struct BeforeQuery {
    #[serde(default)]
    before: Option<i64>,
    #[serde(default)]
    limit: Option<i64>,
}

/// `GET /api/v1/runners/{id}/jobs?before=MS&limit=N`: newest first.
async fn runner_jobs(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path(id): Path<i64>,
    Query(q): Query<BeforeQuery>,
) -> Result<Json<Vec<hub_api::RunnerJob>>, ApiError> {
    let c = caller(&app, &headers).await?;
    require_site_admin(&c)?;
    db::runners::get(&app.db, id).await?.ok_or_else(|| not_found("no such runner"))?;
    let jobs = db::runners::history(&app.db, id, q.limit.unwrap_or(50).clamp(1, 200), q.before).await?;
    Ok(Json(
        jobs.into_iter()
            .map(|j| hub_api::RunnerJob {
                repo: format!("{}/{}", j.owner, j.repo),
                run: j.run_number,
                job: j.job,
                status: j.status,
                started_ms: j.started_ms,
                finished_ms: j.finished_ms,
            })
            .collect(),
    ))
}

/// `GET /api/v1/runners/queue`: running jobs, then queued ones in claim order.
async fn runner_queue(State(app): State<Shared>, headers: HeaderMap) -> Result<Json<Vec<hub_api::QueueItem>>, ApiError> {
    let c = caller(&app, &headers).await?;
    require_site_admin(&c)?;
    Ok(Json(
        db::flow::queue(&app.db)
            .await?
            .into_iter()
            .map(|e| hub_api::QueueItem {
                repo: format!("{}/{}", e.owner, e.name),
                run: e.run_number,
                job: e.job,
                status: e.status,
                runner: e.runner,
            })
            .collect(),
    ))
}

/// `POST .../proposals/{number}/review-requests`: ask an AI assistant the
/// repository may use to review (hub spec §13.4). Accepted at once; the
/// answer arrives as a `comment` review via the assistant.
async fn request_assistant(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, number)): Path<(String, String, i64)>,
    Json(body): Json<hub_api::AssistantRequest>,
) -> Result<(StatusCode, Json<hub_api::AssistantRequest>), ApiError> {
    let c = caller(&app, &headers).await?;
    let me = c.require("proposals:write").or_else(|_| c.require("repo:write"))?.clone();
    let (_, row, role) = reach(&app, &c, &owner, &name, Access::Read).await?;
    let p = db::proposals::get(&app.db, row.id, number).await?.ok_or_else(|| not_found("no such proposal"))?;
    if Some(me.id) != p.author_id && role < Role::Write {
        return Err(forbidden("only the author or a writer asks for reviews"));
    }
    if !p.is_open() {
        return Err(ApiError(StatusCode::CONFLICT, "the proposal is not open".into()));
    }
    let a = crate::assistants::enabled_for_repo(&app.db, &row)
        .await?
        .into_iter()
        .find(|a| a.name.eq_ignore_ascii_case(body.assistant.trim()))
        .ok_or_else(|| ApiError(StatusCode::UNPROCESSABLE_ENTITY, format!("no assistant called {} here", body.assistant.trim())))?;
    let asked = hub_api::AssistantRequest { assistant: a.name.clone() };
    crate::assistants::request_review(&app, &row, &p, &me, a).await.map_err(|e| ApiError(StatusCode::CONFLICT, e))?;
    Ok((StatusCode::ACCEPTED, Json(asked)))
}

// -------------------------------------------------------- assistants (§13.4)

use crate::levels::At;
use crate::web::assistants as aa;

/// The level a repository's assistants live at, for its admins (repo:admin).
async fn repo_level(app: &Shared, c: &Caller, owner: &str, name: &str) -> Result<(Account, At), ApiError> {
    let me = c.require("repo:admin")?.clone();
    let (_, row, _) = reach(app, c, owner, name, Access::Admin).await?;
    Ok((me, At::repo(&row)))
}

/// An organisation's level, for its owners (repo:admin).
async fn org_level(app: &Shared, c: &Caller, org: &str) -> Result<(Account, At), ApiError> {
    let me = c.require("repo:admin")?.clone();
    let o = db::accounts::org_by_name(&app.db, org).await?.ok_or_else(|| not_found("no such organisation"))?;
    if !auth::roles::is_org_owner(&app.db, &me, o.id).await? {
        return Err(not_found("no such organisation"));
    }
    Ok((me, At::org(&o)))
}

/// The site's level, for its administrators.
fn site_level(c: &Caller) -> Result<(Account, At), ApiError> {
    Ok((require_site_admin(c)?.clone(), At::site()))
}

fn put_outcome(r: Result<String, String>) -> Result<(StatusCode, Json<serde_json::Value>), ApiError> {
    match r {
        Ok(msg) => Ok((StatusCode::OK, Json(serde_json::json!({ "ok": msg })))),
        Err(e) => Err(ApiError(StatusCode::UNPROCESSABLE_ENTITY, e)),
    }
}

macro_rules! assistant_routes {
    ($list:ident, $put:ident, $del:ident, $prompt:ident, $prompt_put:ident, ($($p:ident: $t:ty),*), $level:expr) => {
        async fn $list(State(app): State<Shared>, headers: HeaderMap, Path(($($p),*)): Path<($($t),*)>) -> Result<Json<Vec<Assistant>>, ApiError> {
            let c = caller(&app, &headers).await?;
            let (_, at) = $level(&app, &c, $(&$p),*).await?;
            Ok(Json(aa::api_list(&app, &at).await?))
        }
        async fn $put(
            State(app): State<Shared>,
            headers: HeaderMap,
            Path(($($p),*)): Path<($($t),*)>,
            Json(body): Json<NewAssistant>,
        ) -> Result<(StatusCode, Json<serde_json::Value>), ApiError> {
            let c = caller(&app, &headers).await?;
            let (me, at) = $level(&app, &c, $(&$p),*).await?;
            put_outcome(aa::api_put(&app, &me, &at, body).await?)
        }
        async fn $prompt(State(app): State<Shared>, headers: HeaderMap, Path(($($p),*)): Path<($($t),*)>) -> Result<Json<AssistantPrompt>, ApiError> {
            let c = caller(&app, &headers).await?;
            let (_, at) = $level(&app, &c, $(&$p),*).await?;
            Ok(Json(aa::api_prompt(&app, &at).await?))
        }
        async fn $prompt_put(
            State(app): State<Shared>,
            headers: HeaderMap,
            Path(($($p),*)): Path<($($t),*)>,
            Json(body): Json<AssistantPrompt>,
        ) -> Result<Json<AssistantPrompt>, ApiError> {
            let c = caller(&app, &headers).await?;
            let (me, at) = $level(&app, &c, $(&$p),*).await?;
            aa::api_set_prompt(&app, &me, &at, &body.prompt).await?.map_err(|e| ApiError(StatusCode::UNPROCESSABLE_ENTITY, e))?;
            Ok(Json(aa::api_prompt(&app, &at).await?))
        }
    };
}

assistant_routes!(repo_assistants, repo_assistant_put, _rd, repo_prompt, repo_prompt_put, (owner: String, name: String), repo_level);

async fn repo_assistant_delete(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((owner, name, assistant)): Path<(String, String, String)>,
) -> Result<StatusCode, ApiError> {
    let c = caller(&app, &headers).await?;
    let (me, at) = repo_level(&app, &c, &owner, &name).await?;
    if aa::api_delete(&app, &me, &at, &assistant).await? {
        Ok(StatusCode::NO_CONTENT)
    } else {
        Err(not_found("no such assistant at this level"))
    }
}

async fn org_level_one(app: &Shared, c: &Caller, org: &str) -> Result<(Account, At), ApiError> {
    org_level(app, c, org).await
}

async fn org_assistants(State(app): State<Shared>, headers: HeaderMap, Path(org): Path<String>) -> Result<Json<Vec<Assistant>>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (_, at) = org_level_one(&app, &c, &org).await?;
    Ok(Json(aa::api_list(&app, &at).await?))
}

async fn org_assistant_put(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path(org): Path<String>,
    Json(body): Json<NewAssistant>,
) -> Result<(StatusCode, Json<serde_json::Value>), ApiError> {
    let c = caller(&app, &headers).await?;
    let (me, at) = org_level_one(&app, &c, &org).await?;
    put_outcome(aa::api_put(&app, &me, &at, body).await?)
}

async fn org_assistant_delete(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path((org, assistant)): Path<(String, String)>,
) -> Result<StatusCode, ApiError> {
    let c = caller(&app, &headers).await?;
    let (me, at) = org_level_one(&app, &c, &org).await?;
    if aa::api_delete(&app, &me, &at, &assistant).await? {
        Ok(StatusCode::NO_CONTENT)
    } else {
        Err(not_found("no such assistant at this level"))
    }
}

async fn org_prompt(State(app): State<Shared>, headers: HeaderMap, Path(org): Path<String>) -> Result<Json<AssistantPrompt>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (_, at) = org_level_one(&app, &c, &org).await?;
    Ok(Json(aa::api_prompt(&app, &at).await?))
}

async fn org_prompt_put(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path(org): Path<String>,
    Json(body): Json<AssistantPrompt>,
) -> Result<Json<AssistantPrompt>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (me, at) = org_level_one(&app, &c, &org).await?;
    aa::api_set_prompt(&app, &me, &at, &body.prompt).await?.map_err(|e| ApiError(StatusCode::UNPROCESSABLE_ENTITY, e))?;
    Ok(Json(aa::api_prompt(&app, &at).await?))
}

async fn site_assistants(State(app): State<Shared>, headers: HeaderMap) -> Result<Json<Vec<Assistant>>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (_, at) = site_level(&c)?;
    Ok(Json(aa::api_list(&app, &at).await?))
}

async fn site_assistant_put(
    State(app): State<Shared>,
    headers: HeaderMap,
    Json(body): Json<NewAssistant>,
) -> Result<(StatusCode, Json<serde_json::Value>), ApiError> {
    let c = caller(&app, &headers).await?;
    let (me, at) = site_level(&c)?;
    put_outcome(aa::api_put(&app, &me, &at, body).await?)
}

async fn site_assistant_delete(
    State(app): State<Shared>,
    headers: HeaderMap,
    Path(assistant): Path<String>,
) -> Result<StatusCode, ApiError> {
    let c = caller(&app, &headers).await?;
    let (me, at) = site_level(&c)?;
    if aa::api_delete(&app, &me, &at, &assistant).await? {
        Ok(StatusCode::NO_CONTENT)
    } else {
        Err(not_found("no such assistant at this level"))
    }
}

async fn site_prompt(State(app): State<Shared>, headers: HeaderMap) -> Result<Json<AssistantPrompt>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (_, at) = site_level(&c)?;
    Ok(Json(aa::api_prompt(&app, &at).await?))
}

async fn site_prompt_put(
    State(app): State<Shared>,
    headers: HeaderMap,
    Json(body): Json<AssistantPrompt>,
) -> Result<Json<AssistantPrompt>, ApiError> {
    let c = caller(&app, &headers).await?;
    let (me, at) = site_level(&c)?;
    aa::api_set_prompt(&app, &me, &at, &body.prompt).await?.map_err(|e| ApiError(StatusCode::UNPROCESSABLE_ENTITY, e))?;
    Ok(Json(aa::api_prompt(&app, &at).await?))
}