import * as Sentry from "@sentry/node";
import { nodeSentryConfig, drop404s } from "@trails-cool/sentry-config";
import { logger, requestContext } from "./app/lib/logger.server.ts";
import { randomUUID } from "node:crypto";
import { httpRequestDuration } from "./app/lib/metrics.server.ts";
import { createRequestListener } from "@react-router/node";
import { createServer, type IncomingMessage, type ServerResponse } from "node:http";
import { createReadStream, statSync } from "node:fs";
import { join, extname, resolve } from "node:path";
import { setupYjsWebSocket } from "./app/lib/yjs-server.ts";
import { createBoss, startWorker } from "@trails-cool/jobs";
import { expireSessionsJob } from "./app/jobs/expire-sessions.ts";
import { getDatabaseUrl } from "@trails-cool/db";
import postgres, { type Sql } from "postgres";

// See apps/journal/server.ts for the SENTRY_DSN / SENTRY_DISABLED contract.
const sentryDsn = process.env.SENTRY_DSN;
if (process.env.SENTRY_DISABLED !== "true" && sentryDsn) {
  Sentry.init({
    dsn: sentryDsn,
    ...nodeSentryConfig("planner server"),
    beforeSend: drop404s,
  });
}

const port = Number(process.env.PORT ?? 3001);
const CLIENT_DIR = resolve(import.meta.dirname, "build", "client");

const MIME: Record<string, string> = {
  ".js": "application/javascript",
  ".css": "text/css",
  ".html": "text/html",
  ".json": "application/json",
  ".png": "image/png",
  ".jpg": "image/jpeg",
  ".svg": "image/svg+xml",
  ".ico": "image/x-icon",
  ".woff": "font/woff",
  ".woff2": "font/woff2",
};

function serveStatic(req: IncomingMessage, res: ServerResponse): boolean {
  if (req.method !== "GET" && req.method !== "HEAD") return false;

  const url = new URL(req.url ?? "/", `http://${req.headers.host}`);
  const filePath = resolve(join(CLIENT_DIR, url.pathname));

  if (!filePath.startsWith(CLIENT_DIR)) return false;

  try {
    if (!statSync(filePath).isFile()) return false;
  } catch {
    return false;
  }

  res.setHeader("Content-Type", MIME[extname(filePath)] ?? "application/octet-stream");
  if (url.pathname.startsWith("/assets/")) {
    res.setHeader("Cache-Control", "public, immutable, max-age=31536000");
  }
  createReadStream(filePath).pipe(res);
  return true;
}

const listener = createRequestListener({
  build: () => import("./build/server/index.js") as never,
});

async function handleMetrics(_req: IncomingMessage, res: ServerResponse): Promise<void> {
  const { registry } = await import("./app/lib/metrics.server.ts");
  const metrics = await registry.metrics();
  res.writeHead(200, { "Content-Type": registry.contentType });
  res.end(metrics);
}

const version = process.env.SENTRY_RELEASE ?? "dev";

// Module-level singleton dedicated to /health (mirrors PR #430 for the
// journal). Previously a fresh client + connection was opened on every
// probe; under monitoring cadence that's a fresh handshake every few
// seconds. Kept separate from any future main-app pool so a starvation
// event on the app pool doesn't fail the liveness probe.
let healthClient: Sql | null = null;
function getHealthClient(): Sql {
  if (!healthClient) {
    healthClient = postgres(getDatabaseUrl(), { max: 2, idle_timeout: 30 });
  }
  return healthClient;
}

async function handleHealth(_req: IncomingMessage, res: ServerResponse): Promise<void> {
  try {
    await getHealthClient()`SELECT 1`;
    res.writeHead(200, { "Content-Type": "application/json" });
    res.end(JSON.stringify({ status: "ok", version, db: "connected" }));
  } catch {
    res.writeHead(503, { "Content-Type": "application/json" });
    res.end(JSON.stringify({ status: "degraded", version, db: "unreachable" }));
  }
}

const server = createServer((req, res) => {
  const url = req.url ?? "/";
  const start = Date.now();

  // Honor an inbound X-Request-Id (e.g. from Caddy or a probe) so the
  // request ID propagates across the proxy hop; otherwise mint a fresh
  // UUID. Echo on the response so clients can correlate.
  const inbound = req.headers["x-request-id"];
  const requestId =
    (Array.isArray(inbound) ? inbound[0] : inbound) || randomUUID();
  res.setHeader("X-Request-Id", requestId);

  requestContext.run({ requestId }, () => {
    if (!url.startsWith("/assets/") && url !== "/health" && url !== "/metrics") {
      res.on("finish", () => {
        const duration = Date.now() - start;
        logger.info({ method: req.method, path: url, status: res.statusCode, duration }, "request");
        httpRequestDuration.observe(
          { method: req.method ?? "GET", route: url.split("?")[0]!, status: String(res.statusCode) },
          duration / 1000,
        );
      });
    }

    if (url === "/health") { handleHealth(req, res); return; }
    if (url === "/metrics") { handleMetrics(req, res); return; }
    if (!serveStatic(req, res)) {
      listener(req, res);
    }
  });
});

setupYjsWebSocket(server);

server.listen(port, async () => {
  logger.info({ port }, "Planner server listening");
  logger.info({ port, path: "/sync/:sessionId" }, "Yjs WebSocket available");

  const boss = createBoss(getDatabaseUrl());
  await startWorker(boss, [expireSessionsJob]);
  logger.info("Background job worker started");
});