//! Pages (hub spec §6): the router, the shell every template extends, the
//! error page, viewer-aware lookups and askama filters. Handlers are thin:
//! they resolve names, call the view layer under the repository lock, and
//! render.

mod admin;
mod assistants;
mod avatar;
pub mod chain;
mod device;
pub mod edit;
pub mod filters;
pub mod flow;
mod forks;
pub mod help;
pub mod history;
pub mod home;
mod inbox;
pub mod issues;
mod orgs;
pub mod projects;
pub mod proposals;
mod recovery;
mod refs;
pub mod release_trust;
pub mod releases;
mod repo;
mod repo_settings;
mod resolve;
pub mod runners;
mod session;
pub(crate) mod settings;
mod statics;
mod webhooks;

use crate::auth::{self, Access, Role, Viewer};
use crate::repos::RepoError;
use crate::{db, Shared};
use askama::Template;
use axum::extract::DefaultBodyLimit;
use axum::http::{header, StatusCode};
use axum::response::{Html, IntoResponse, Redirect, Response};
use axum::routing::{any, get, post};
use axum::Router;
use tower_http::compression::CompressionLayer;
use tower_http::trace::TraceLayer;

pub fn router(app: Shared) -> Router {
    let push_limit = app.config.limits.push_body_limit.0 as usize;
    Router::new()
        .route("/", get(home::index))
        .route("/explore", get(home::explore))
        .route("/avatar/{name}", get(avatar::avatar))
        .route("/health", get(home::health))
        .route("/about", get(home::about))
        .route("/.well-known/oxyhub-key", get(home::hub_key))
        .route("/.well-known/oxyhub-ca.pem", get(home::hub_ca))
        .route("/style.css", get(statics::style))
        .route("/favicon.svg", get(statics::favicon))
        .route("/favicon.ico", get(statics::favicon))
        .route("/static/{*path}", get(statics::asset))
        .route("/login", get(session::login_form).post(session::login))
        .route("/device", get(device::form).post(device::answer))
        .route("/logout", post(session::logout))
        .route("/register", get(session::register_form).post(session::register))
        .route("/settings", get(settings::profile).post(settings::update_profile))
        .route("/settings/password", post(settings::change_password))
        .route("/settings/appearance", post(settings::appearance))
        .route("/settings/security", get(settings::security))
        .route("/settings/security/totp/begin", post(settings::totp_begin))
        .route("/settings/security/totp/enable", post(settings::totp_enable))
        .route("/settings/security/totp/disable", post(settings::totp_disable))
        .route("/settings/security/sessions", post(settings::sessions_reset))
        .route("/settings/keys", get(settings::keys))
        .route("/settings/keys/upload", post(settings::keys_upload))
        .route("/settings/keys/verify", post(settings::keys_verify))
        .route("/settings/keys/unlink", post(settings::keys_unlink))
        .route("/settings/tokens", get(settings::tokens).post(settings::tokens_create))
        .route("/settings/tokens/{id}/delete", post(settings::tokens_delete))
        .route("/new", get(repo_settings::new_form).post(repo_settings::create))
        .route("/orgs/new", get(orgs::new_form).post(orgs::create))
        .route("/orgs/{name}/settings", get(orgs::settings).post(orgs::update))
        .route("/orgs/{name}/settings/members", post(orgs::member))
        .route("/orgs/{name}/settings/teams", post(orgs::team))
        .route("/orgs/{name}/settings/hooks", post(orgs::hooks))
        .route("/orgs/{name}/settings/assistants", post(orgs::assistants))
        .route("/orgs/{name}/settings/runners/token", post(orgs::runner_token))
        .route("/orgs/{name}/settings/runners/{id}/remove", post(orgs::runner_remove))
        .route("/orgs/{name}/settings/hooks/{id}/deliveries", get(orgs::deliveries))
        .route("/orgs/{name}/settings/hooks/{id}/redeliver/{delivery}", post(orgs::redeliver))
        .route("/orgs/{name}/settings/avatar", post(orgs::avatar).layer(DefaultBodyLimit::max(avatar::MAX_BYTES + (64 << 10))))
        .route("/settings/avatar", post(settings::avatar).layer(DefaultBodyLimit::max(avatar::MAX_BYTES + (64 << 10))))
        .route("/notifications", get(inbox::inbox))
        .route("/notifications/read", post(inbox::mark_read))
        .route("/settings/notifications", get(inbox::unsubscribe).post(inbox::prefs))
        .route("/search", get(inbox::search))
        .route("/admin", get(admin::index))
        .route("/admin/registration", post(admin::set_mode))
        .route("/admin/invite", post(admin::invite))
        .route("/admin/account", post(admin::account))
        .route("/admin/storage", get(admin::storage).post(admin::maintain))
        .route("/admin/runners", get(runners::list))
        .route("/admin/runners/settings", get(runners::settings).post(runners::save_settings))
        .route("/admin/runners/token", post(runners::new_token))
        .route("/admin/runners/{id}", get(runners::show))
        .route("/admin/runners/{id}/state", post(runners::set_state))
        .route("/admin/runners/{id}/scope", post(runners::set_scope))
        .route("/admin/runners/{id}/limits", post(runners::set_limits))
        .route("/admin/mail", post(admin::set_mail))
        .route("/admin/mail/test", post(admin::test_mail))
        .route("/admin/assistants", post(admin::assistants))
        .route("/admin/runners/{id}/remove", post(runners::remove))
        .nest("/api/v1", crate::api::router(app.config.limits.asset_limit.0 as usize))
        .route("/{owner}", get(home::owner))
        .route("/{owner}/{name}", get(repo::overview))
        .route("/{owner}/{name}/tree/{r}", get(repo::tree_root))
        .route("/{owner}/{name}/tree/{r}/{*path}", get(repo::tree))
        .route("/{owner}/{name}/file/{r}/{*path}", get(repo::file))
        .route("/{owner}/{name}/function/{r}/{*path}", get(history::function))
        .route("/{owner}/{name}/lanes/{r}", get(history::lanes))
        .route("/{owner}/{name}/lanes/{r}/plan", post(history::plan))
        .route("/{owner}/{name}/raw/{r}/{*path}", get(repo::raw_file))
        .route("/{owner}/{name}/last/{r}", get(repo::last_changes))
        .route("/{owner}/{name}/changes/{r}", get(history::history))
        .route("/{owner}/{name}/change/{hash}", get(history::change))
        .route("/apt", get(crate::apt::home))
        .route("/apt/{file}", get(crate::apt::key))
        .route("/apt/dists/{suite}/{*rest}", get(crate::apt::dists))
        .route("/apt/pool/{*path}", get(crate::apt::pool))
        .route("/help", get(help::help))
        .route("/projects/{owner}", get(projects::list).post(projects::create))
        .route("/projects/{owner}/{number}", get(projects::show).post(projects::act))
        .route("/notifications/thread", post(inbox::thread))
        .route("/notifications/open/{id}", get(inbox::open))
        .route("/login/reset", get(recovery::request_form).post(recovery::request))
        .route("/login/reset/{secret}", get(recovery::new_password_form).post(recovery::set_new_password))
        .route("/verify/{secret}", get(recovery::verify))
        .route("/settings/email/verify", post(settings::resend_verification))
        .route("/{owner}/{name}/compare", get(history::compare_index))
        .route("/{owner}/{name}/compare/{spec}", get(history::compare))
        .route("/{owner}/{name}/bookmarks", get(refs::bookmarks))
        .route("/{owner}/{name}/bookmarks/delete", post(refs::delete_bookmark))
        .route("/{owner}/{name}/tags", get(refs::tags))
        .route("/{owner}/{name}/conflicts", get(refs::conflicts))
        .route("/{owner}/{name}/trust", get(refs::trust))
        .route("/{owner}/{name}/pushes", get(refs::pushes))
        .route("/{owner}/{name}/fork", get(forks::form).post(forks::create))
        .route("/{owner}/{name}/forks", get(forks::list))
        .route("/{owner}/{name}/settings", get(repo_settings::settings).post(repo_settings::update))
        .route("/{owner}/{name}/settings/collaborators", post(repo_settings::collaborator))
        .route("/{owner}/{name}/settings/delete", post(repo_settings::delete))
        .route("/{owner}/{name}/settings/requirements", post(repo_settings::requirements))
        .route("/{owner}/{name}/proposals", get(proposals::list))
        .route("/{owner}/{name}/proposals/new", get(proposals::new_form).post(proposals::create))
        .route("/{owner}/{name}/proposals/new/draft", post(proposals::new_draft))
        .route("/{owner}/{name}/proposal/{number}", get(proposals::show))
        .route("/{owner}/{name}/proposal/{number}/comment", post(proposals::comment))
        .route("/{owner}/{name}/proposal/{number}/comment/{id}/resolve", post(proposals::resolve_comment))
        .route("/{owner}/{name}/proposal/{number}/review", post(proposals::review))
        .route("/{owner}/{name}/proposal/{number}/reviewers", post(proposals::reviewers))
        .route("/{owner}/{name}/proposal/{number}/assistant", post(proposals::assistant))
        .route("/{owner}/{name}/proposal/{number}/draft", post(proposals::draft))
        .route("/{owner}/{name}/proposal/{number}/edit", post(proposals::edit))
        .route("/{owner}/{name}/proposal/{number}/state", post(proposals::state))
        .route("/{owner}/{name}/proposal/{number}/land", post(proposals::land))
        .route("/{owner}/{name}/proposal/{number}/labels", post(proposals::set_labels))
        .route("/{owner}/{name}/proposal/{number}/project", post(projects::place_proposal))
        .route("/{owner}/{name}/issue/{number}/project", post(projects::place_issue))
        .route("/{owner}/{name}/proposal/{number}/events", get(proposals::events))
        .route("/{owner}/{name}/settings/hooks", post(repo_settings::hooks))
        .route("/{owner}/{name}/settings/assistants", post(repo_settings::assistants))
        .route("/{owner}/{name}/settings/hooks/{id}/deliveries", get(repo_settings::deliveries))
        .route("/{owner}/{name}/settings/hooks/{id}/redeliver/{delivery}", post(repo_settings::redeliver))
        .route("/{owner}/{name}/settings/checks", post(repo_settings::required_checks))
        .route("/{owner}/{name}/watch", post(issues::watch))
        .route("/{owner}/{name}/star", post(issues::star))
        .route("/{owner}/{name}/edit/{r}", post(edit::save))
        .route("/{owner}/{name}/edit/{r}/{*path}", get(edit::edit_form))
        .route("/{owner}/{name}/resolve/{bookmark}/{*path}", get(resolve::form).post(resolve::save))
        .route("/{owner}/{name}/resolve-live/{bookmark}/{*path}", get(resolve::live_events).post(resolve::live_choose))
        .route("/{owner}/{name}/newfile/{r}", get(edit::new_form))
        .route("/{owner}/{name}/flow", get(flow::runs))
        .route("/{owner}/{name}/flow/badge.svg", get(flow::badge))
        .route("/{owner}/{name}/flow/{id}", get(flow::run))
        .route("/{owner}/{name}/flow/{id}/live", get(flow::live))
        .route("/{owner}/{name}/flow/start", post(flow::start))
        .route("/{owner}/{name}/flow/{id}/rerun", post(flow::rerun))
        .route("/{owner}/{name}/flow/{id}/cancel", post(flow::cancel))
        .route("/{owner}/{name}/flow/stamp/{r}", get(flow::stamp))
        .route("/{owner}/{name}/flow/at/{r}", get(flow::at))
        .route("/{owner}/{name}/receipts/{attest}", get(flow::receipt_file))
        .route("/{owner}/{name}/flow/{id}/artifacts/{job}/{artifact}", get(flow::artifact_file))
        .route("/{owner}/{name}/flow/{id}/artifacts/{job}/{artifact}/attach", post(flow::attach))
        .route("/{owner}/{name}/releases", get(releases::list))
        .route("/{owner}/{name}/releases/new", get(releases::new_form).post(releases::create))
        .route("/{owner}/{name}/releases/tag/{*tag}", get(releases::show))
        .route("/{owner}/{name}/releases/trust/{*tag}", get(release_trust::page))
        .route("/{owner}/{name}/releases/edit/{id}", post(releases::edit))
        .route(
            "/{owner}/{name}/releases/upload/{id}",
            post(releases::upload).layer(DefaultBodyLimit::max(app.config.limits.asset_limit.0 as usize + (1 << 20))),
        )
        .route("/{owner}/{name}/asset/{id}/{file}", get(releases::download))
        .route("/{owner}/{name}/archive", get(releases::source_archive))
        .route("/{owner}/{name}/search", get(repo::code_search))
        .route("/{owner}/{name}/info/{*rest}", any(git_info))
        .route("/{owner}/{name}/HEAD", get(git_head))
        .route("/{owner}/{name}/objects/{*rest}", get(git_objects))
        .route("/{owner}/{name}/git-upload-pack", post(git_upload_pack))
        .route("/{owner}/{name}/git-receive-pack", post(git_receive_pack))
        .route("/{owner}/{name}/settings/mirror", post(repo_settings::mirror))
        .route("/{owner}/{name}/settings/flow", post(repo_settings::flow))
        .route("/{owner}/{name}/settings/runners/token", post(repo_settings::runner_token))
        .route("/{owner}/{name}/settings/runners/{id}/remove", post(repo_settings::runner_remove))
        .route("/{owner}/{name}/issues", get(issues::list))
        .route("/{owner}/{name}/issues/new", get(issues::new_form).post(issues::create))
        .route("/{owner}/{name}/issue/{number}", get(issues::show))
        .route("/{owner}/{name}/issue/{number}/comment", post(issues::comment))
        .route("/{owner}/{name}/issue/{number}/comment/{id}/delete", post(issues::delete_comment))
        .route("/{owner}/{name}/issue/{number}/edit", post(issues::edit))
        .route("/{owner}/{name}/issue/{number}/state", post(issues::state))
        .route("/{owner}/{name}/issue/{number}/labels", post(issues::set_labels))
        .route("/{owner}/{name}/issue/{number}/assign", post(issues::assign))
        .route("/{owner}/{name}/issue/{number}/milestone", post(issues::set_milestone))
        .route("/{owner}/{name}/issue/{number}/subscribe", post(issues::subscribe))
        .route("/{owner}/{name}/labels", get(issues::labels).post(issues::save_label))
        .route("/{owner}/{name}/milestones", get(issues::milestones).post(issues::save_milestone))
        .route("/{owner}/{name}/oxy/v1/{endpoint}", any(crate::protocol::dispatch).layer(DefaultBodyLimit::max(push_limit)))
        .fallback(not_found)
        .layer(axum::middleware::from_fn_with_state(app.clone(), same_origin))
        .layer(CompressionLayer::new())
        .layer(TraceLayer::new_for_http())
        .with_state(app)
}

// Git's smart HTTP paths under `/{owner}/{name}.git/`, forwarded to the
// mirror (hub spec §14).
async fn git_info(
    st: axum::extract::State<Shared>,
    axum::extract::Path((o, n, rest)): axum::extract::Path<(String, String, String)>,
    m: axum::http::Method,
    q: axum::extract::RawQuery,
    h: axum::http::HeaderMap,
    b: axum::body::Bytes,
) -> Response {
    crate::mirror::serve(st, axum::extract::Path((o, n, format!("info/{rest}"))), m, q, h, b).await
}

async fn git_head(
    st: axum::extract::State<Shared>,
    axum::extract::Path((o, n)): axum::extract::Path<(String, String)>,
    m: axum::http::Method,
    q: axum::extract::RawQuery,
    h: axum::http::HeaderMap,
    b: axum::body::Bytes,
) -> Response {
    crate::mirror::serve(st, axum::extract::Path((o, n, "HEAD".into())), m, q, h, b).await
}

async fn git_objects(
    st: axum::extract::State<Shared>,
    axum::extract::Path((o, n, rest)): axum::extract::Path<(String, String, String)>,
    m: axum::http::Method,
    q: axum::extract::RawQuery,
    h: axum::http::HeaderMap,
    b: axum::body::Bytes,
) -> Response {
    crate::mirror::serve(st, axum::extract::Path((o, n, format!("objects/{rest}"))), m, q, h, b).await
}

async fn git_upload_pack(
    st: axum::extract::State<Shared>,
    axum::extract::Path((o, n)): axum::extract::Path<(String, String)>,
    m: axum::http::Method,
    q: axum::extract::RawQuery,
    h: axum::http::HeaderMap,
    b: axum::body::Bytes,
) -> Response {
    crate::mirror::serve(st, axum::extract::Path((o, n, "git-upload-pack".into())), m, q, h, b).await
}

async fn git_receive_pack(
    st: axum::extract::State<Shared>,
    axum::extract::Path((o, n)): axum::extract::Path<(String, String)>,
    m: axum::http::Method,
    q: axum::extract::RawQuery,
    h: axum::http::HeaderMap,
    b: axum::body::Bytes,
) -> Response {
    crate::mirror::serve(st, axum::extract::Path((o, n, "git-receive-pack".into())), m, q, h, b).await
}

/// Cross-site form posts are refused (hub spec §15.2): a browser that
/// sends `Origin` or `Sec-Fetch-Site` must name this site. Protocol and
/// API clients send neither.
async fn same_origin(
    axum::extract::State(app): axum::extract::State<Shared>,
    req: axum::extract::Request,
    next: axum::middleware::Next,
) -> Response {
    if req.method() != axum::http::Method::GET && req.method() != axum::http::Method::HEAD {
        let headers = req.headers();
        if headers.get("sec-fetch-site").and_then(|v| v.to_str().ok()) == Some("cross-site") {
            return (StatusCode::FORBIDDEN, "cross-site request refused").into_response();
        }
        if let Some(origin) = headers.get(header::ORIGIN).and_then(|v| v.to_str().ok()) {
            let host_of = |u: &str| u.split("://").nth(1).unwrap_or(u).split('/').next().unwrap_or("").to_ascii_lowercase();
            let request_host = headers.get(header::HOST).and_then(|v| v.to_str().ok()).map(|h| h.to_ascii_lowercase());
            let ok = host_of(origin) == host_of(app.config.base_url()) || request_host.as_deref() == Some(host_of(origin).as_str());
            if !ok && origin != "null" {
                return (StatusCode::FORBIDDEN, "cross-site request refused").into_response();
            }
        }
    }
    next.run(req).await
}

/// What every page's chrome needs.
#[derive(Clone, Debug)]
pub struct Shell {
    pub site: String,
    pub base_url: String,
    pub path: String,
    pub version: &'static str,
    /// What was built: `oxy describe` at deploy, a Flow build's heads, or "local build".
    pub build: &'static str,
    /// The signed-in username, if any.
    pub user: Option<String>,
    pub is_admin: bool,
    pub csrf: String,
    pub unread: i64,
}

impl Shell {
    pub fn new(app: &Shared, path: &str, viewer: &Viewer) -> Shell {
        Shell {
            site: app.config.site.name.clone(),
            base_url: app.config.base_url().to_string(),
            path: path.to_string(),
            version: env!("CARGO_PKG_VERSION"),
            build: env!("OXY_BUILD_ID"),
            user: viewer.account().map(|a| a.username.clone()),
            is_admin: viewer.is_admin(),
            csrf: viewer.csrf().to_string(),
            unread: viewer.0.as_ref().map(|v| v.unread).unwrap_or(0),
        }
    }

    pub fn anonymous(app: &Shared, path: &str) -> Shell {
        Shell::new(app, path, &Viewer(None))
    }
}

/// The repository chrome: tabs and counts.
#[derive(Clone, Debug)]
pub struct RepoShell {
    pub owner: String,
    pub name: String,
    pub url: String,
    pub description: String,
    pub default_bookmark: String,
    pub visibility: String,
    pub tab: &'static str,
    pub clone_url: String,
    /// The viewer's role, for showing settings and write actions.
    pub role: Option<Role>,
    /// Open issues and proposals, shown on their tabs.
    pub open_issues: i64,
    pub open_proposals: i64,
}

impl RepoShell {
    pub fn new(app: &Shared, row: &db::repos::RepoRow, tab: &'static str) -> RepoShell {
        RepoShell {
            owner: row.owner.clone(),
            name: row.name.clone(),
            url: format!("/{}/{}", row.owner, row.name),
            description: row.description.clone(),
            default_bookmark: row.default_bookmark.clone(),
            visibility: row.visibility.clone(),
            tab,
            clone_url: format!("{}/{}/{}", app.config.base_url(), row.owner, row.name),
            role: None,
            open_issues: row.open_issues,
            open_proposals: row.open_proposals,
        }
    }

    pub fn with_role(mut self, role: Role) -> RepoShell {
        self.role = Some(role);
        self
    }

    pub fn can(&self, access: Access) -> bool {
        auth::roles::allows(self.role, access)
    }

    pub fn can_maintain(&self) -> bool {
        self.can(Access::Maintain)
    }
}

/// Render a template as an HTML response.
/// One page of a long list: which page, how many, and links that keep
/// the rest of the query.
#[derive(Clone, Debug)]
pub struct Pager {
    pub page: usize,
    pub pages: usize,
    pub total: usize,
    /// The query without `page`, each pair encoded, joined with `&`.
    query: String,
}

impl Pager {
    pub const PER_PAGE: usize = 25;

    /// `page` counts from 1; out-of-range pages clamp to the last.
    pub fn new(total: usize, page: Option<usize>, query: &[(&str, &str)]) -> Pager {
        let pages = total.div_ceil(Self::PER_PAGE).max(1);
        let page = page.unwrap_or(1).clamp(1, pages);
        let query = query
            .iter()
            .filter(|(_, v)| !v.is_empty())
            .map(|(k, v)| format!("{k}={}", settings::urlencode(v).replace('/', "%2F")))
            .collect::<Vec<_>>()
            .join("&");
        Pager { page, pages, total, query }
    }

    /// This page's items.
    pub fn slice<T>(&self, all: Vec<T>) -> Vec<T> {
        all.into_iter().skip((self.page - 1) * Self::PER_PAGE).take(Self::PER_PAGE).collect()
    }

    pub fn url(&self, page: usize) -> String {
        if self.query.is_empty() {
            format!("?page={page}")
        } else {
            format!("?{}&page={page}", self.query)
        }
    }

    /// The same query with another sort, back on page one.
    pub fn sorted(&self, sort: &str) -> String {
        let rest: Vec<&str> = self.query.split('&').filter(|p| !p.is_empty() && !p.starts_with("sort=")).collect();
        let mut q = rest.join("&");
        if !q.is_empty() {
            q.push('&');
        }
        format!("?{q}sort={sort}")
    }
}

pub struct Page<T: Template>(pub T);

impl<T: Template> IntoResponse for Page<T> {
    fn into_response(self) -> Response {
        match self.0.render() {
            Ok(s) => Html(s).into_response(),
            Err(e) => {
                tracing::error!("template: {e}");
                (StatusCode::INTERNAL_SERVER_ERROR, "template error").into_response()
            }
        }
    }
}

#[derive(Template)]
#[template(path = "error.html")]
struct ErrorPage {
    shell: Shell,
    status: u16,
    title: String,
    detail: String,
}

/// A page-level failure, rendered inside the shell, or a redirect.
#[derive(Debug)]
pub struct Error {
    pub status: StatusCode,
    pub detail: String,
    shell: Option<Box<Shell>>,
    redirect: Option<String>,
}

impl Error {
    pub fn redirect(to: String) -> Error {
        Error { status: StatusCode::SEE_OTHER, detail: String::new(), shell: None, redirect: Some(to) }
    }

    pub fn not_found(shell: Shell) -> Error {
        Error {
            status: StatusCode::NOT_FOUND,
            detail: "There is nothing at this address.".into(),
            shell: Some(Box::new(shell)),
            redirect: None,
        }
    }

    pub fn bad(shell: Shell, detail: impl Into<String>) -> Error {
        Error { status: StatusCode::BAD_REQUEST, detail: detail.into(), shell: Some(Box::new(shell)), redirect: None }
    }

    pub fn from_repo(shell: Shell, e: RepoError) -> Error {
        match e {
            RepoError::NotFound => Error::not_found(shell),
            RepoError::Oxy(oxy_core::repo::RepoError::Msg(m)) => {
                Error { status: StatusCode::NOT_FOUND, detail: m, shell: Some(Box::new(shell)), redirect: None }
            }
            other => {
                Error { status: StatusCode::INTERNAL_SERVER_ERROR, detail: other.to_string(), shell: Some(Box::new(shell)), redirect: None }
            }
        }
    }

    pub fn from_db(shell: Shell, e: sqlx::Error) -> Error {
        Error { status: StatusCode::INTERNAL_SERVER_ERROR, detail: e.to_string(), shell: Some(Box::new(shell)), redirect: None }
    }
}

impl IntoResponse for Error {
    fn into_response(self) -> Response {
        if let Some(to) = self.redirect {
            return Redirect::to(&to).into_response();
        }
        let title = match self.status {
            StatusCode::NOT_FOUND => "Not found",
            StatusCode::BAD_REQUEST => "Bad request",
            _ => "Something went wrong",
        };
        if self.status.is_server_error() {
            tracing::error!("{}", self.detail);
        }
        let shell = self.shell.map(|b| *b).unwrap_or(Shell {
            site: "OxygenHub".into(),
            base_url: String::new(),
            path: String::new(),
            version: "",
            build: "",
            user: None,
            is_admin: false,
            csrf: String::new(),
            unread: 0,
        });
        let page = ErrorPage { shell, status: self.status.as_u16(), title: title.into(), detail: self.detail };
        match page.render() {
            Ok(s) => (self.status, Html(s)).into_response(),
            Err(_) => (self.status, title).into_response(),
        }
    }
}

async fn not_found(axum::extract::State(app): axum::extract::State<Shared>, viewer: Viewer, uri: axum::http::Uri) -> Response {
    Error::not_found(Shell::new(&app, uri.path(), &viewer)).into_response()
}

/// A raw file response with a safe content type (hub spec §15.2).
pub fn raw(bytes: Vec<u8>, name: &str, inline_image: bool) -> Response {
    let mime = mime_of(name);
    let disposition = if inline_image && mime.starts_with("image/") { "inline" } else { "attachment" };
    (
        [
            (header::CONTENT_TYPE, mime.to_string()),
            (header::CONTENT_DISPOSITION, format!("{disposition}; filename=\"{}\"", name.replace('"', ""))),
            (header::X_CONTENT_TYPE_OPTIONS, "nosniff".to_string()),
        ],
        bytes,
    )
        .into_response()
}

pub fn mime_of(name: &str) -> &'static str {
    match name.rsplit('.').next().map(|e| e.to_ascii_lowercase()).as_deref() {
        Some("png") => "image/png",
        Some("jpg" | "jpeg") => "image/jpeg",
        Some("gif") => "image/gif",
        Some("webp") => "image/webp",
        Some("svg") => "image/svg+xml",
        Some("pdf") => "application/pdf",
        Some(
            "txt" | "md" | "rs" | "toml" | "json" | "yml" | "yaml" | "c" | "h" | "cpp" | "hpp" | "py" | "js" | "ts" | "html" | "css" | "sh",
        ) => "text/plain; charset=utf-8",
        _ => "application/octet-stream",
    }
}

/// Resolve `{owner}/{name}` for the viewer with at least `access`, or 404:
/// a repository the viewer may not see does not exist for them (hub spec
/// §4.4). Returns the viewer's role too.
pub async fn lookup_role(
    app: &Shared,
    shell: &Shell,
    viewer: &Viewer,
    owner: &str,
    name: &str,
    access: Access,
) -> Result<(crate::repos::RepoName, db::repos::RepoRow, Role), Error> {
    let repo = crate::repos::RepoName::new(owner, name).ok_or_else(|| Error::not_found(shell.clone()))?;
    let row = db::repos::get(&app.db, owner, name)
        .await
        .map_err(|e| Error::from_db(shell.clone(), e))?
        .ok_or_else(|| Error::not_found(shell.clone()))?;
    let role = auth::roles::role_for(&app.db, viewer.account(), &row).await.map_err(|e| Error::from_db(shell.clone(), e))?;
    if !auth::roles::allows(role, access) {
        return Err(Error::not_found(shell.clone()));
    }
    Ok((repo, row, role.unwrap_or(Role::Read)))
}

/// `lookup_role` for reading.
pub async fn lookup(
    app: &Shared,
    shell: &Shell,
    viewer: &Viewer,
    owner: &str,
    name: &str,
) -> Result<(crate::repos::RepoName, db::repos::RepoRow, Role), Error> {
    lookup_role(app, shell, viewer, owner, name, Access::Read).await
}

/// Fill `account` on change authors whose key is linked to an account.
pub async fn attribute(app: &Shared, changes: &mut [&mut crate::repos::view::ChangeView]) {
    if changes.is_empty() {
        return;
    }
    let Ok(links) = db::accounts::identity_accounts(&app.db).await else { return };
    let map: std::collections::HashMap<String, String> = links.into_iter().collect();
    for c in changes.iter_mut() {
        if let Some(u) = map.get(&c.author.key) {
            c.author.account = Some(u.clone());
        }
    }
}