// apps/api/src/server.ts
// Fastify server entry. Hosts:
//   - /api/health
//   - /api/analysis/* (REST endpoints in routes/analysis.ts)
//   - / (static legacy SPA from apps/web-legacy/, with SPA fallback)

import Fastify, { type FastifyInstance } from "fastify";
import fastifyStatic from "@fastify/static";
import fastifyMultipart from "@fastify/multipart";
import { fileURLToPath } from "node:url";
import { dirname, resolve } from "node:path";
import { existsSync, mkdirSync } from "node:fs";

import { loadConfig } from "./config.js";
import { createLogger } from "./log.js";
import { createStore } from "./queue/store-factory.js";
import { registerHealthRoutes } from "./routes/health.js";
import { registerAnalysisRoutes } from "./routes/analysis.js";
import { registerPolishRoutes } from "./routes/polish.js";
import { QueueRunner } from "./queue/runner.js";

const __filename = fileURLToPath(import.meta.url);
const __dirname = dirname(__filename);

// Inside the container the layout is:
//   /app/apps/api/dist/server.js   ← this file
//   /app/apps/web-legacy/dist/index.html
// In dev (tsx) it's the source path with the same parent layout.
function resolveWebLegacyRoot(): string {
  const webRoot = resolve(__dirname, "../../web-legacy/dist");
  if (!existsSync(resolve(webRoot, "index.html"))) {
    throw new Error("前端静态产物不存在，请先运行 pnpm --filter @task-optimizer/web-legacy build 或 pnpm build");
  }
  return webRoot;
}

async function buildServer(): Promise<{ app: FastifyInstance; runner: QueueRunner }> {
  const config = loadConfig();
  const logger = createLogger(config.logLevel);

  // Ensure storage directories exist (volume-mounted in Docker)
  for (const dir of [config.uploadDir, config.exportDir]) {
    try {
      mkdirSync(dir, { recursive: true });
    } catch (err) {
      logger.error({ err, dir }, "Failed to create storage directory");
      throw err;
    }
  }

  const store = await createStore(config);
  const runner = new QueueRunner({ store, config, logger });

  // Recover any jobs left in `running` state across restarts (mark queued items
  // as queued is a no-op; the runner picks them back up on demand).
  for (const job of await store.listResumableJobs()) {
    logger.info({ jobId: job.id }, "Recovering resumable job from previous run");
    await store.recoverInterruptedJob(job.id);
    runner.scheduleJob(job.id);
  }

  const app = Fastify({
    // Fastify 5 requires `loggerInstance` (not `logger`) when passing an
    // already-constructed pino instance.
    loggerInstance: logger,
    bodyLimit: config.maxUploadMB * 1024 * 1024,
    disableRequestLogging: false,
    trustProxy: true,
  });

  await app.register(fastifyMultipart, {
    limits: {
      fileSize: config.maxUploadMB * 1024 * 1024,
      files: config.maxBatchFiles,
    },
  });

  // ── /api routes ─────────────────────────────────────────────────────────
  await registerHealthRoutes(app);
  await registerPolishRoutes(app, { config });
  await registerAnalysisRoutes(app, { store, config, runner });
  app.addHook("onClose", async () => {
    await store.close();
  });

  // ── static SPA ──────────────────────────────────────────────────────────
  const webRoot = resolveWebLegacyRoot();
  await app.register(fastifyStatic, {
    root: webRoot,
    prefix: "/",
    decorateReply: false,
  });

  // SPA fallback — anything that isn't /api/* and isn't a real file falls back
  // to index.html so the legacy frontend can handle its own routes.
  app.setNotFoundHandler((req, reply) => {
    if (req.raw.url && req.raw.url.startsWith("/api/")) {
      reply.code(404).send({ code: 404, msg: "Not Found" });
      return;
    }
    reply.sendFile("index.html", webRoot);
  });

  return { app, runner };
}

async function main() {
  const { app, runner } = await buildServer();
  const config = loadConfig();

  const shutdown = async (signal: string) => {
    app.log.info({ signal }, "Shutdown signal received, closing server");
    runner.requestShutdown();
    try {
      await app.close();
    } catch (err) {
      app.log.error({ err }, "Error closing Fastify");
    }
    process.exit(0);
  };
  process.once("SIGINT", () => void shutdown("SIGINT"));
  process.once("SIGTERM", () => void shutdown("SIGTERM"));

  try {
    await app.listen({ port: config.port, host: "0.0.0.0" });
    app.log.info({ port: config.port }, "Server listening");
  } catch (err) {
    app.log.error({ err }, "Server failed to start");
    process.exit(1);
  }
}

main().catch((err) => {
  console.error("Fatal startup error:", err);
  process.exit(1);
});