use std::sync::Arc;

use api_types::{
    ADMIN_SETTINGS, ADMIN_USERS, AUTH_LOGIN, AUTH_LOGOUT, AUTH_ME, AUTH_SETUP, FILES, SHARE, SHARES,
};
use axum::Router;
use axum::http::HeaderValue;
use axum::routing::{delete, get, post, put};
use tower_http::set_header::SetResponseHeaderLayer;

use crate::error::AppState;

/// Content-Security-Policy tuned to the built Trunk frontend.
///
/// * `script-src 'unsafe-inline'` — Trunk emits one inline bootstrap module
///   in index.html; every real JS file also carries an SRI integrity hash.
/// * `'wasm-unsafe-eval'` — compiling the same-origin WASM module.
/// * `style-src 'unsafe-inline'` — the context menu sets an inline `style=`.
/// * Everything else locked to the same origin; frames/plugins banned.
const CSP: &str = "default-src 'self'; script-src 'self' 'unsafe-inline' 'wasm-unsafe-eval'; style-src 'self' 'unsafe-inline'; img-src 'self' data: blob:; media-src 'self' blob:; connect-src 'self'; font-src 'self' data:; object-src 'none'; base-uri 'self'; form-action 'self'; frame-ancestors 'none';";

/// Content-Security-Policy for served *user files* that the browser would
/// treat as a scripting document (HTML, SVG, XML). Lets such a file render as
/// a real page — the "share an HTML page" flow — without letting it act as the
/// app.
///
/// The security hinges on one omission: `allow-scripts` **without**
/// `allow-same-origin`. That forces the document into a unique opaque origin,
/// so its JavaScript cannot read the session cookie's origin, cannot touch
/// `localStorage`, and cannot call `/api` as the viewer (the server sends no
/// CORS headers, so every cross-origin read fails). Never add
/// `allow-same-origin` here.
///
/// Also deliberately absent:
/// * `allow-top-navigation` — a shared page cannot silently redirect the
///   viewer elsewhere. `-by-user-activation` still lets links work on click.
/// * `allow-popups-to-escape-sandbox` — a popup would drop the sandbox.
///
/// `connect-src *` is deliberate: a shared page may call third-party APIs.
/// The trade-off is that it can also beacon (report that the link was opened,
/// and anything the page itself contains). It cannot exfiltrate anything of
/// the viewer's — the opaque origin means it has no session and no CORS read
/// access to this server.
pub(crate) const FILE_CSP: &str = "default-src 'self'; script-src 'self' 'unsafe-inline'; style-src 'self' 'unsafe-inline'; img-src 'self' data: blob:; media-src 'self' blob:; font-src 'self' data:; connect-src *; object-src 'none'; frame-ancestors 'none'; sandbox allow-scripts allow-forms allow-modals allow-downloads allow-popups allow-top-navigation-by-user-activation;";

/// True for MIME types the browser parses as a scripting document. These are
/// the responses that need [`FILE_CSP`]; everything else keeps the app policy.
///
/// This reads the *declared* type — the same value that becomes the
/// `Content-Type` header — on purpose. If the sandbox decision and the render
/// decision ever read different inputs, a file can be rendered as a scripting
/// document without being sandboxed.
pub(crate) fn is_scriptable_mime(mime: &str) -> bool {
    let base = mime.split(';').next().unwrap_or("").trim();
    matches!(
        base,
        "text/html" | "application/xhtml+xml" | "image/svg+xml" | "text/xml" | "application/xml"
    ) || base.ends_with("+xml")
}

mod admin;
mod auth;
mod common;
mod files;
mod shares;
mod spa;

pub fn router(state: Arc<AppState>) -> Router {
    // Route patterns: the server side of the shared endpoint strings in
    // `api_types` (axum copies them into the route table on insert).
    let files_root = format!("{FILES}/{{root_id}}");
    let files_item = format!("{FILES}/{{root_id}}/{{*path}}");
    let shares_id = format!("{SHARES}/{{id}}");
    let share_token = format!("{SHARE}/{{token}}");
    let admin_user_id = format!("{ADMIN_USERS}/{{id}}");

    Router::new()
        .route(AUTH_LOGIN, post(auth::login))
        .route(AUTH_LOGOUT, post(auth::logout))
        .route(AUTH_ME, get(auth::me))
        .route(AUTH_SETUP, post(auth::setup))
        .route(&files_root, get(files::list_root))
        .route(&files_item, get(files::file_get))
        .route(&files_item, put(files::file_put))
        .route(&files_root, post(files::dispatch_root))
        .route(&files_item, post(files::dispatch))
        .route(&files_item, delete(files::delete))
        .route(SHARES, get(shares::list))
        .route(SHARES, post(shares::create))
        .route(&shares_id, delete(shares::delete))
        .route(&share_token, get(shares::resolve))
        .route(ADMIN_USERS, get(admin::list_users))
        .route(ADMIN_USERS, post(admin::create_user))
        .route(&admin_user_id, put(admin::update_user))
        .route(&admin_user_id, delete(admin::delete_user))
        .route(ADMIN_SETTINGS, get(admin::get_settings))
        .route(ADMIN_SETTINGS, put(admin::update_settings))
        .fallback(spa::fallback)
        .with_state(state)
        // Hard security headers on every response (API and static alike).
        // CSP is `if_not_present` so that file responses can substitute the
        // sandboxed [`FILE_CSP`]; everything else gets the app policy.
        .layer(SetResponseHeaderLayer::if_not_present(
            "content-security-policy".parse().unwrap(),
            HeaderValue::from_static(CSP),
        ))
        .layer(SetResponseHeaderLayer::overriding(
            "x-content-type-options".parse().unwrap(),
            HeaderValue::from_static("nosniff"),
        ))
        .layer(SetResponseHeaderLayer::overriding(
            "x-frame-options".parse().unwrap(),
            HeaderValue::from_static("DENY"),
        ))
        .layer(SetResponseHeaderLayer::overriding(
            "referrer-policy".parse().unwrap(),
            HeaderValue::from_static("no-referrer"),
        ))
}