import "dotenv/config";

import cors from "cors";
import express, { NextFunction, Request, Response } from "express";
import helmet from "helmet";
import morgan from "morgan";
import path from "node:path";
import fs from "node:fs";

import { responseMiddleware } from "./middlewares/response.middleware";
import router from "./routes/index.route";
import { HttpError } from "./utils/httpError";

const app = express();

app.set("trust proxy", true);

app.use(helmet());
app.use(cors({ origin: true }));
app.use(express.json({ limit: "1mb" }));
app.use(express.urlencoded({ extended: true }));
app.use(morgan(process.env.NODE_ENV === "production" ? "combined" : "dev"));

app.use(responseMiddleware);
app.use(router);

const distPublic = path.join(__dirname, "public");
const frontDist = path.join(process.cwd(), "frontEnd", "dist");
const staticDir = fs.existsSync(distPublic) ? distPublic : frontDist;
if (fs.existsSync(staticDir)) {
  app.use(express.static(staticDir));
}

// SPA fallback for non-API GET requests
app.use((req: Request, res: Response, next: NextFunction) => {
  if (req.method !== "GET") return next();
  if (req.path.startsWith("/api")) return next();
  if (fs.existsSync(path.join(staticDir, "index.html"))) {
    res.sendFile(path.join(staticDir, "index.html"));
    return;
  }
  next();
});

app.use((req: Request, res: Response) => {
  res.status(404).json({
    error: {
      code: "NOT_FOUND",
      message: `Route not found: ${req.method} ${req.path}`
    }
  });
});

app.use((err: unknown, _req: Request, res: Response, _next: NextFunction) => {
  if (err instanceof HttpError) {
    res.status(err.status).json({
      error: {
        code: err.code,
        message: err.message,
        details: err.details ?? null
      }
    });
    return;
  }

  res.status(500).json({
    error: {
      code: "INTERNAL_SERVER_ERROR",
      message: "Unexpected error"
    }
  });
});

const PORT = normalizePort(process.env.PORT ?? "3000");

if (require.main === module) {
  app.listen(PORT, () => {
    console.log(`服务已运行: http://localhost:${PORT}`);
  });
}

export default app;

function normalizePort(value: string): number {
  const parsed = Number.parseInt(value, 10);
  if (Number.isNaN(parsed) || parsed <= 0) return 3000;
  return parsed;
}