import { Elysia } from "elysia";
import { Eta } from "eta";
import { resolve } from "path";
import { createHash } from "crypto";
import sql from "./db";
import { loadStatusPage, loadPagePayload, loadMonitorDetail, type Window } from "./data";
import { renderRss } from "./render/rss";
import { renderBadge, badgeFromState } from "./render/badge";
import { cached } from "./cache";
import { allow } from "./rate-limit";
import { checkPassword, makeAuthCookie, verifyAuthCookie } from "./auth";

// Crash isolation: log loudly, never exit. Status pages going down silently is
// worse than weird logs.
process.on("unhandledRejection", (reason) => console.error("[unhandledRejection]", reason));
process.on("uncaughtException",  (err)    => console.error("[uncaughtException]",  err));

const eta = new Eta({ views: resolve(import.meta.dir, "./views"), cache: true, defaultExtension: ".ejs" });

const PUBLIC_BASE = process.env.STATUS_BASE_URL ?? "https://status.pingql.com";

// Hash the static assets so their URLs change whenever their bytes change.
// Used as cache-busting query strings on the <link>/<script> tags so visitors
// always pull the freshest CSS/JS even with the long-lived `immutable`
// Cache-Control we set on the asset routes below.
const expandJsPath = resolve(import.meta.dir, "./static/expand.js");
const expandJsBytes = await Bun.file(expandJsPath).bytes();
const expandJsHash = createHash("md5").update(expandJsBytes).digest("hex").slice(0, 8);

const appCssPath = resolve(import.meta.dir, "./static/app.css");
const appCssBytes = await Bun.file(appCssPath).bytes();
const appCssHash = createHash("md5").update(appCssBytes).digest("hex").slice(0, 8);

function clientIp(req: Request): string {
  return req.headers.get("x-forwarded-for")?.split(",")[0]?.trim()
    || req.headers.get("cf-connecting-ip")
    || "unknown";
}

// 404s must NOT be cached by browsers or Cloudflare. The same URL frequently
// flips between "200 with data" and "404 not-found" — for example when an
// operator adds a password to a previously-public page, or when a slug
// changes, or when a monitor is removed. If Cloudflare cached a 404 (default
// behaviour for unspecified Cache-Control on 404 responses) the operator
// would see stale 404s for the entire edge TTL. Likewise, an old 200 cached
// at the edge could keep serving image/svg+xml headers over a now-changed
// body, which is exactly the symptom that prompted this fix.
//
// no-store is the bluntest form: never store, always revalidate. Pair with
// 404 status so any layer in front knows not to hold on to it.
const NO_STORE_HEADERS = {
  "cache-control": "no-store, must-revalidate",
  "pragma":        "no-cache",
} as const;

function notFound(): Response {
  return new Response(eta.render("not-found", {}), {
    status: 404,
    headers: {
      "content-type": "text/html; charset=utf-8",
      ...NO_STORE_HEADERS,
    },
  });
}

function jsonNotFound(): Response {
  return new Response(JSON.stringify({ error: "not found" }), {
    status: 404,
    headers: {
      "content-type": "application/json",
      ...NO_STORE_HEADERS,
    },
  });
}

function rateLimited(): Response {
  return new Response("Too many requests", { status: 429 });
}

function isAuthorised(page: { id: string; password_hash: string | null }, req: Request): boolean {
  if (!page.password_hash) return true;
  // Pass the current password_hash so verifyAuthCookie can derive the
  // expected pwTag and reject any cookie that was issued under a previous
  // password — i.e. rotating the password evicts every existing session.
  return verifyAuthCookie(req.headers.get("cookie"), page.id, page.password_hash);
}

// Memoirist (Elysia's router) treats `:slug.json` as a single parameter named
// "slug.json" and refuses to coexist with `:slug`. Instead, use one `:slug`
// route and dispatch on the suffix in the handler.
function splitSlugAndFormat(raw: string): { slug: string; format: "html" | "json" | "rss" } {
  if (raw.endsWith(".json")) return { slug: raw.slice(0, -5), format: "json" };
  if (raw.endsWith(".rss"))  return { slug: raw.slice(0, -4), format: "rss"  };
  return { slug: raw, format: "html" };
}

async function renderHtml(slug: string, request: Request): Promise<Response> {
  // Page row is fetched fresh on every request — never cached. The page row
  // carries the live password_hash + index_search + display config; an
  // operator changing any of those in the dashboard must take effect
  // immediately, not after a TTL window. The single PK lookup is sub-ms,
  // and the heavy work (rollup payload below) is still cached for 15s.
  const page = await loadStatusPage(slug);
  if (!page) return notFound();
  if (!isAuthorised(page, request)) {
    return new Response(eta.render("password", { title: page.title, slug: page.slug, error: null }), {
      status: 401,
      headers: { "content-type": "text/html; charset=utf-8", ...NO_STORE_HEADERS },
    });
  }
  const payload = await cached(`payload:${slug}`, 15, () => loadPagePayload(slug));
  if (!payload) return notFound();
  const html = eta.render("page", { ...payload, expandJsHash, appCssHash });
  // Password-protected pages MUST be private — never let an edge cache or
  // shared proxy hold a copy that some other visitor could pull. Public
  // pages keep the 15s shared cache for performance under viral hits.
  const cacheControl = page.password_hash
    ? "private, no-store, must-revalidate"
    : "public, max-age=15, s-maxage=15";
  const headers: Record<string, string> = {
    "content-type":   "text/html; charset=utf-8",
    "cache-control":  cacheControl,
    "x-frame-options":"SAMEORIGIN",
    "x-content-type-options": "nosniff",
    "referrer-policy":"strict-origin-when-cross-origin",
  };
  if (!page.index_search) headers["x-robots-tag"] = "noindex, nofollow";
  return new Response(html, { headers });
}

async function renderJson(slug: string, request: Request, win?: Window): Promise<Response> {
  // Same as renderHtml: never cache the page row. The auth check has to see
  // the live password_hash, otherwise rotating a password leaves a 15s
  // window where old cookies still validate against the stale row.
  const page = await loadStatusPage(slug);
  // Both nonexistent and gated-without-cookie collapse to the same 404 so a
  // scraper iterating slugs against /<slug>.json can't use the response code
  // as an oracle for which slugs are private. Forces any OSINT enumeration to
  // fall back to HTML scraping (which gets the password form, also a 401-ish
  // signal but more expensive to parse and less stable).
  if (!page || !isAuthorised(page, request)) return jsonNotFound();
  const cacheKey = `payload:${slug}:${win ?? page.default_window}`;
  const payload = await cached(cacheKey, 15, () => loadPagePayload(slug, win));
  if (!payload) return jsonNotFound();
  // Password-protected JSON must be private — same reasoning as renderHtml.
  const cacheControl = page.password_hash
    ? "private, no-store, must-revalidate"
    : "public, max-age=15, s-maxage=15";
  return new Response(JSON.stringify(payload), {
    headers: {
      "content-type":  "application/json",
      "cache-control": cacheControl,
      ...(page.index_search ? {} : { "x-robots-tag": "noindex, nofollow" }),
    },
  });
}

async function renderRssResp(slug: string, request: Request): Promise<Response> {
  const page = await loadStatusPage(slug);
  if (!page) return notFound();
  // Password-protected pages must NOT leak incident text via RSS. Without
  // this check anyone with the slug could pull every incident update on a
  // private page just by hitting /<slug>.rss. Match the page-existence 404
  // exactly so an unauthenticated scraper can't even tell whether a slug
  // is gated vs. nonexistent.
  if (!isAuthorised(page, request)) return notFound();
  const xml = await cached(`rss:${slug}`, 300, () => renderRss(page, PUBLIC_BASE));
  // Authenticated visitor on a private page → never edge-cache the response.
  const cacheControl = page.password_hash
    ? "private, no-store, must-revalidate"
    : "public, max-age=300, s-maxage=300";
  return new Response(xml, {
    headers: {
      "content-type":  "application/rss+xml; charset=utf-8",
      "cache-control": cacheControl,
    },
  });
}

const app = new Elysia()
  // No status page lives at the root — show the same 404 visitors get for any
  // unknown slug, so a stray hit on the apex doesn't leak service identity.
  .get("/", () => notFound())

  // Static expand.js — cached aggressively, hash-busted via query string.
  .get("/_static/expand.js", () => new Response(Bun.file(expandJsPath), {
    headers: {
      "content-type":  "application/javascript; charset=utf-8",
      "cache-control": "public, max-age=31536000, immutable",
    },
  }))

  // Static app.css — same caching contract as expand.js. The query string in
  // the <link> tag is the file's MD5 hash, so deploys propagate immediately
  // even though the asset itself is marked immutable for a year.
  .get("/_static/app.css", () => new Response(Bun.file(appCssPath), {
    headers: {
      "content-type":  "text/css; charset=utf-8",
      "cache-control": "public, max-age=31536000, immutable",
    },
  }))

  // Single public route — dispatches HTML / JSON / RSS by extension on the slug.
  .get("/:slug", async ({ params, request, query }) => {
    const { slug, format } = splitSlugAndFormat(params.slug);
    if (!allow(slug, clientIp(request))) return rateLimited();
    if (format === "json") return renderJson(slug, request, (query as any)?.window as Window | undefined);
    if (format === "rss")  return renderRssResp(slug, request);
    return renderHtml(slug, request);
  })

  // Public SVG badge. Password-protected pages 404 here so an unauthenticated
  // shields-style embed can't reveal a private page's current state — and
  // crucially can't even confirm whether a private slug exists, since the
  // 404 is identical to a totally bogus slug.
  .get("/:slug/badge.svg", async ({ params, request }) => {
    if (!allow(params.slug, clientIp(request))) return rateLimited();
    const page = await loadStatusPage(params.slug);
    if (!page) return notFound();
    if (!isAuthorised(page, request)) return notFound();
    const payload = await cached(`payload:${params.slug}`, 15, () => loadPagePayload(params.slug));
    if (!payload) return notFound();
    const { message, color } = badgeFromState(payload.monitors);
    const svg = renderBadge("status", message, color);
    // Same private/no-store rule on authenticated badge fetches for private pages.
    const cacheControl = page.password_hash
      ? "private, no-store, must-revalidate"
      : "public, max-age=15, s-maxage=15";
    return new Response(svg, {
      headers: {
        "content-type":  "image/svg+xml",
        "cache-control": cacheControl,
      },
    });
  })

  // Per-monitor detail JSON for the click-to-expand UI in compact mode.
  // Path is /:slug/monitor/:idWithExt where idWithExt is e.g. "abc123.json".
  // We strip the .json suffix in the handler — same trick as the slug route to
  // dodge memoirist's "two params at the same position" rule.
  .get("/:slug/monitor/:idWithExt", async ({ params, request, query }) => {
    if (!allow(params.slug, clientIp(request))) return rateLimited();
    // Same password gate as the page-level JSON. Without this, the click-to-
    // expand endpoint would happily serve uptime / region state / incidents
    // for monitors on a password-protected page to anyone who guesses the
    // monitor id (8 hex bytes). Match the page existence 404 so unauthenticated
    // requests can't even tell whether a slug is gated.
    const page = await loadStatusPage(params.slug);
    if (!page || !isAuthorised(page, request)) return jsonNotFound();
    const idWithExt = params.idWithExt;
    const monitorId = idWithExt.endsWith(".json") ? idWithExt.slice(0, -5) : idWithExt;
    const win = (query as any)?.window as Window | undefined;
    const cacheKey = `monitor:${params.slug}:${monitorId}:${win ?? ''}`;
    const payload = await cached(cacheKey, 15, () => loadMonitorDetail(params.slug, monitorId, win));
    if (!payload) return jsonNotFound();
    const cacheControl = page.password_hash
      ? "private, no-store, must-revalidate"
      : "public, max-age=15, s-maxage=15";
    return new Response(JSON.stringify(payload), {
      headers: {
        "content-type":  "application/json",
        "cache-control": cacheControl,
      },
    });
  })

  // PWA manifest. Rate-limited like every other public endpoint, and
  // password-gated 404s match the page-existence 404 so a scraper can't use
  // this route as an oracle for which slugs exist behind a password gate.
  .get("/:slug/manifest.json", async ({ params, request }) => {
    if (!allow(params.slug, clientIp(request))) return rateLimited();
    const page = await loadStatusPage(params.slug);
    if (!page) return notFound();
    if (!isAuthorised(page, request)) return notFound();
    return new Response(JSON.stringify({
      name:             page.title,
      short_name:       page.title.slice(0, 12),
      description:      page.description ?? "",
      start_url:        `/${page.slug}`,
      display:          "standalone",
      background_color: page.theme === "light" ? "#ffffff" : "#0a0a0a",
      theme_color:      page.theme === "light" ? "#0ea5e9" : "#0a0a0a",
    }), {
      headers: {
        "content-type":  "application/manifest+json",
        "cache-control": page.password_hash
          ? "private, no-store, must-revalidate"
          : "public, max-age=86400, s-maxage=86400",
      },
    });
  })

  // Password gate POST
  .post("/:slug/auth", async ({ params, request }) => {
    if (!allow(params.slug, clientIp(request))) return rateLimited();
    const page = await loadStatusPage(params.slug);
    if (!page) return notFound();
    if (!page.password_hash) {
      return Response.redirect(`/${page.slug}`, 303);
    }
    const form = await request.formData();
    const password = String(form.get("password") ?? "");
    const ok = await checkPassword(password, page.password_hash);
    if (!ok) {
      return new Response(eta.render("password", { title: page.title, slug: page.slug, error: "Wrong password" }), {
        status: 401,
        headers: { "content-type": "text/html; charset=utf-8" },
      });
    }
    return new Response(null, {
      status: 303,
      headers: { "location": `/${page.slug}`, "set-cookie": makeAuthCookie(page.id, page.password_hash) },
    });
  });

const port = Number(process.env.STATUS_PORT ?? 3003);
const server = Bun.serve({
  port,
  fetch(req) { return app.handle(req); },
});

console.log(`PingQL status service running at http://localhost:${server.port}`);