import type { Server } from "bun";
import { loadConfig } from "./config";
import { json, jsonError, notFound, securityHeaders } from "./http";
import { log } from "./log";
import { RateLimiter } from "./ratelimit";
import { handleAuth } from "./routes/auth";
import { handleDelete } from "./routes/delete";
import { handleDownload } from "./routes/download";
import { handleUpload } from "./routes/upload";
import { Storage } from "./storage";

const cfg = loadConfig();

const storage = new Storage(cfg.storageDir);
await storage.init();
const secret = await storage.loadSecret();
const sweep = await storage.sweep();
if (sweep.removedFiles > 0 || sweep.removedMetadata > 0) {
  log(
    "info",
    `startup sweep removed ${sweep.removedFiles} orphaned file(s), ${sweep.removedMetadata} orphaned metadata record(s)`,
  );
}

const limiter = new RateLimiter(cfg.rateLimitMax, cfg.rateLimitWindowMs);
const startedAt = Date.now();

const STATIC_ROUTES: Record<string, { file: string; type: string }> = {
  "/": { file: "./public/index.html", type: "text/html; charset=utf-8" },
  "/index.html": { file: "./public/index.html", type: "text/html; charset=utf-8" },
  "/style.css": { file: "./public/style.css", type: "text/css; charset=utf-8" },
  "/app.js": { file: "./public/app.js", type: "text/javascript; charset=utf-8" },
};

const staticContent = new Map<string, { body: string; type: string }>();
for (const [route, info] of Object.entries(STATIC_ROUTES)) {
  staticContent.set(route, {
    body: await Bun.file(new URL(info.file, import.meta.url)).text(),
    type: info.type,
  });
}

const server = Bun.serve({
  hostname: cfg.host,
  port: cfg.port,
  maxRequestBodySize: Infinity,
  fetch(req, srv) {
    return route(req, srv).catch((err) => {
      log("error", `unhandled error: ${err instanceof Error ? (err.stack ?? err.message) : String(err)}`);
      return jsonError(500, "internal error");
    });
  },
});

function clientIp(req: Request, srv: Server<undefined>): string {
  if (cfg.trustProxy) {
    const xff = req.headers.get("x-forwarded-for");
    if (xff) {
      const first = xff.split(",")[0]?.trim();
      if (first) return first;
    }
    const cf = req.headers.get("cf-connecting-ip");
    if (cf) return cf;
  }
  return srv.requestIP(req)?.address ?? "unknown";
}

function serveStatic(path: string): Response {
  const entry = staticContent.get(path);
  if (!entry) return notFound();
  return new Response(entry.body, {
    headers: {
      "content-type": entry.type,
      "cache-control": "no-cache",
      "content-security-policy":
        "default-src 'self'; base-uri 'none'; form-action 'self'; frame-ancestors 'none'",
      ...securityHeaders(),
    },
  });
}

function isSecure(req: Request, url: URL): boolean {
  if (cfg.trustProxy) return req.headers.get("x-forwarded-proto") === "https";
  return url.protocol === "https:";
}

async function route(req: Request, srv: Server<undefined>): Promise<Response> {
  const url = new URL(req.url);
  const path = url.pathname;
  const method = req.method;

  if (method === "GET" && staticContent.has(path)) return serveStatic(path);

  if (path === "/api/health" && method === "GET") {
    return json({ status: "ok", uptimeSeconds: Math.round((Date.now() - startedAt) / 1000) });
  }

  if (path === "/api/upload" && method === "POST") {
    return handleUpload(req, storage, cfg.maxFileSize);
  }

  if (path.startsWith("/api/auth/") && method === "POST") {
    if (cfg.rateLimitEnabled && !limiter.check(clientIp(req, srv))) {
      return jsonError(429, "too many requests");
    }
    return handleAuth(req, storage, path.slice("/api/auth/".length), secret, isSecure(req, url));
  }

  if (path.startsWith("/d/") && (method === "GET" || method === "HEAD")) {
    if (cfg.rateLimitEnabled && !limiter.check(clientIp(req, srv))) {
      return jsonError(429, "too many requests");
    }
    return handleDownload(req, storage, path.slice(3), secret);
  }

  if (path.startsWith("/api/files/") && method === "DELETE") {
    if (cfg.rateLimitEnabled && !limiter.check(clientIp(req, srv))) {
      return jsonError(429, "too many requests");
    }
    return handleDelete(req, storage, path.slice("/api/files/".length));
  }

  return notFound();
}

log(
  "info",
  `listening on http://${cfg.host}:${cfg.port} storage=${cfg.storageDir} maxUpload=${cfg.maxFileSize}`,
);

for (const signal of ["SIGINT", "SIGTERM"] as const) {
  process.once(signal, () => {
    log("info", `received ${signal}, shutting down`);
    server.stop();
    process.exit(0);
  });
}

process.on("unhandledRejection", (reason) => {
  log("error", `unhandled rejection: ${reason instanceof Error ? reason.message : String(reason)}`);
});