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

pub mod filters;
mod history;
mod home;
mod refs;
mod repo;
mod statics;

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, Response};
use axum::routing::{any, get};
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("/health", get(home::health))
        .route("/.well-known/oxyhub-key", get(home::hub_key))
        .route("/style.css", get(statics::style))
        .route("/favicon.svg", get(statics::favicon))
        .route("/favicon.ico", get(statics::favicon))
        .route("/static/{*path}", get(statics::asset))
        .nest("/api/v1", crate::api::router())
        .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}/last/{r}", get(repo::last_changes))
        .route("/{owner}/{name}/changes/{r}", get(history::history))
        .route("/{owner}/{name}/change/{hash}", get(history::change))
        .route("/{owner}/{name}/compare/{spec}", get(history::compare))
        .route("/{owner}/{name}/bookmarks", get(refs::bookmarks))
        .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}/oxy/v1/{endpoint}", any(crate::protocol::dispatch).layer(DefaultBodyLimit::max(push_limit)))
        .fallback(not_found)
        .layer(CompressionLayer::new())
        .layer(TraceLayer::new_for_http())
        .with_state(app)
}

/// 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,
}

impl Shell {
    pub fn new(app: &Shared, path: &str) -> 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"),
        }
    }
}

/// 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,
}

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),
        }
    }
}

/// Render a template as an HTML response.
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.
#[derive(Debug)]
pub struct Error {
    pub status: StatusCode,
    pub detail: String,
    shell: Option<Shell>,
}

impl Error {
    pub fn not_found(shell: Shell) -> Error {
        Error { status: StatusCode::NOT_FOUND, detail: "There is nothing at this address.".into(), shell: Some(shell) }
    }

    pub fn bad(shell: Shell, detail: impl Into<String>) -> Error {
        Error { status: StatusCode::BAD_REQUEST, detail: detail.into(), shell: Some(shell) }
    }

    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(shell) },
            other => Error { status: StatusCode::INTERNAL_SERVER_ERROR, detail: other.to_string(), shell: Some(shell) },
        }
    }

    pub fn from_db(shell: Shell, e: sqlx::Error) -> Error {
        Error { status: StatusCode::INTERNAL_SERVER_ERROR, detail: e.to_string(), shell: Some(shell) }
    }
}

impl IntoResponse for Error {
    fn into_response(self) -> 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.unwrap_or(Shell { site: "Oxygenhub".into(), base_url: String::new(), path: String::new(), version: "" });
        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>, uri: axum::http::Uri) -> Response {
    Error::not_found(Shell::new(&app, uri.path())).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}` to its row, or 404. Private repositories are
/// invisible until accounts exist (hub 0.2).
pub async fn lookup(app: &Shared, shell: &Shell, owner: &str, name: &str) -> Result<(crate::repos::RepoName, db::repos::RepoRow), 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))?;
    match row {
        Some(r) if r.visibility() == hub_api::Visibility::Public => Ok((repo, r)),
        _ => Err(Error::not_found(shell.clone())),
    }
}