import "dotenv/config";
import express from "express";
import { createServer } from "http";
import net from "net";
import fs from "fs";
import path from "path";
import { fileURLToPath } from "url";
import mysql from "mysql2/promise";
import { createExpressMiddleware } from "@trpc/server/adapters/express";
import { appRouter } from "../routers";
import { createContext } from "./context";
import { serveStatic, setupVite } from "./vite";
import { fileRouter } from "../fileRoutes";
import { ensureBootstrapAdmin } from "./auth";

const SERVER_ROOT = path.dirname(fileURLToPath(import.meta.url));

const sleep = (ms: number) => new Promise(resolve => setTimeout(resolve, ms));

/**
 * Run SQL migrations using a raw mysql2 connection.
 * Drizzle's execute() requires tagged template sql``; using mysql2 directly
 * is safer for running arbitrary migration statements.
 */
async function runMigrations() {
  if (!process.env.DATABASE_URL) return;

  // Wait for MySQL to be ready (up to 40 s)
  let conn: mysql.Connection | null = null;
  for (let i = 1; i <= 20; i++) {
    try {
      conn = await mysql.createConnection(process.env.DATABASE_URL);
      console.log("[Migration] Database ready.");
      break;
    } catch {
      console.log(`[Migration] Waiting for database... (${i}/20)`);
      await sleep(2000);
    }
  }
  if (!conn) {
    console.warn("[Migration] Database not available after 40 s, skipping migrations.");
    return;
  }

  try {
    const migrationsDir = path.resolve(SERVER_ROOT, "../../drizzle");
    if (!fs.existsSync(migrationsDir)) return;

    const sqlFiles = fs.readdirSync(migrationsDir)
      .filter(f => f.endsWith(".sql"))
      .sort();

    // Tracking table
    await conn.execute(`
      CREATE TABLE IF NOT EXISTS \`_migrations\` (
        \`name\` VARCHAR(255) PRIMARY KEY,
        \`appliedAt\` TIMESTAMP DEFAULT CURRENT_TIMESTAMP
      )
    `);

    for (const file of sqlFiles) {
      const [rows] = await conn.execute(
        `SELECT name FROM \`_migrations\` WHERE name = ?`, [file]
      ) as [mysql.RowDataPacket[], mysql.FieldPacket[]];

      if (rows.length > 0) continue; // already applied

      const sqlText = fs.readFileSync(path.join(migrationsDir, file), "utf8");
      // Split on ";". Do NOT drop statements that start with "--": each CREATE block
      // begins with comment lines, and filtering those skipped all tables (bug).
      const statements = sqlText
        .split(";")
        .map(s => s.trim())
        .filter(s => s.length > 0);

      for (const stmt of statements) {
        try {
          await conn.execute(stmt);
        } catch (e: any) {
          if (!e.message?.includes("already exists")) {
            console.error(`[Migration] Error in ${file}:`, e.message);
          }
        }
      }

      await conn.execute(
        `INSERT IGNORE INTO \`_migrations\` (name) VALUES (?)`, [file]
      );
      console.log(`[Migration] Applied: ${file}`);
    }
  } finally {
    await conn.end();
  }
}

function isPortAvailable(port: number): Promise<boolean> {
  return new Promise(resolve => {
    const server = net.createServer();
    server.listen(port, () => {
      server.close(() => resolve(true));
    });
    server.on("error", () => resolve(false));
  });
}

async function findAvailablePort(startPort: number = 3000): Promise<number> {
  for (let port = startPort; port < startPort + 20; port++) {
    if (await isPortAvailable(port)) {
      return port;
    }
  }
  throw new Error(`No available port found starting from ${startPort}`);
}

async function startServer() {
  await runMigrations();
  await ensureBootstrapAdmin();
  const app = express();
  const server = createServer(app);
  // Configure body parser with larger size limit for file uploads
  app.use(express.json({ limit: "50mb" }));
  app.use(express.urlencoded({ limit: "50mb", extended: true }));

  // 文件上传路由单独设置超长超时（50 GB 点云，按 100 MB/s 约需 8 分钟，留 60 分钟余量）
  server.timeout = 0;          // 禁用 Node http.Server 全局超时
  server.keepAliveTimeout = 0; // 长连接不超时
  server.headersTimeout = 0;   // 读请求头不超时
  // 禁止代理（NPS 等）缓存 API 响应
  app.use('/api', (_req, res, next) => {
    res.setHeader('Cache-Control', 'no-store, no-cache, must-revalidate');
    res.setHeader('Pragma', 'no-cache');
    next();
  });
  // File API for local file browsing
  app.use('/api/files', fileRouter);
  // tRPC API
  app.use(
    "/api/trpc",
    createExpressMiddleware({
      router: appRouter,
      createContext,
    })
  );
  // development mode uses Vite, production mode uses static files
  if (process.env.NODE_ENV === "development") {
    await setupVite(app, server);
  } else {
    serveStatic(app);
  }

  const preferredPort = parseInt(process.env.PORT || "3000");
  const port = await findAvailablePort(preferredPort);

  if (port !== preferredPort) {
    console.log(`Port ${preferredPort} is busy, using port ${port} instead`);
  }

  server.listen(port, () => {
    console.log(`Server running on http://localhost:${port}/`);
  });
}

startServer().catch(console.error);