import fs from 'node:fs/promises';
import { URL } from 'node:url';
import { Transform } from 'node:stream';
import { Readable } from 'node:stream';
import { pipeline } from 'node:stream/promises';
import { serve } from '@hono/node-server';
import { Hono } from 'hono';
import { createServer as createNodeServer } from 'node:http';
import process from 'node:process';

// 创建 Hono 应用
const app = new Hono();// API路由

import api from './src/server/api.ts';


app.route('/', api);


// Constants
const isProduction = process.env.NODE_ENV === 'production';
const port = process.env.PORT || 8080;
const base = process.env.BASE || '/';
const ABORT_DELAY = 10000;

// 解析基础路径为 URL 对象，方便后续处理
const baseUrl = new URL(base, `http://localhost:${port}`);



// 使用 Hono 的 serve 启动服务器
const parentServer = serve({
  fetch: app.fetch,
  createServer: createNodeServer,
  port: port,
}, () => {
  console.log(`Server started at http://localhost:${port}`);
});

// Cached production assets
let templateHtml = '';
if (isProduction) {
  templateHtml = await fs.readFile('./dist/client/index.html', 'utf-8');
}

// 生产环境中间件
let compressionMiddleware;
let sirvMiddleware;
if (isProduction) {
  compressionMiddleware = (await import('compression')).default();
  sirvMiddleware = (await import('sirv')).default('./dist/client', { 
    extensions: [],
    baseUrl: base 
  });
}

// Vite 开发服务器
/** @type {import('vite').ViteDevServer | undefined} */
let vite;
if (!isProduction) {
  const { createServer } = await import('vite');
  vite = await createServer({
    server: { middlewareMode: {
        server: parentServer
      },
      hmr: {  
        port: 8081,
        clientPort: 443, // 或其他可用端口  
        path: 'vite-hmr'
      },
      proxy: {
        '/vite-hmr': {
          target: 'ws://localhost:8081',
          // Proxying WebSocket
          ws: true,
        },
      },
    },
    appType: 'custom',
    base,
  });
}

// 将请求处理逻辑适配为 Hono 中间件
app.use(async (c) => {
  try {
    // 使用 c.env 获取原生请求响应对象（关键修复）
    const req = c.env.incoming;
    const res = c.env.outgoing;
    const url = new URL(req.url, `http://${req.headers.host}`);
    const path = url.pathname;

    // 检查是否匹配基础路径
    if (!path.startsWith(baseUrl.pathname)) {
      return c.text('Not found', 404);
    }

    // 处理基础路径
    const normalizedUrl = path.replace(baseUrl.pathname, '/') || '/';

    // 开发环境：使用 Vite 中间件
    if (!isProduction && vite) {
      // 使用 Vite 中间件处理请求
      const handled = await new Promise((resolve) => {
        vite.middlewares(req, res, () => resolve(false));
      });
      
      // 如果 Vite 中间件已经处理了请求，直接返回
      if (handled) {
        return c.body;
      }
    } 
    // 生产环境：使用 compression 和 sirv 中间件
    else if (isProduction) {
      // 先尝试 compression 中间件
      const compressed = await new Promise((resolve) => {
        compressionMiddleware(req, res, () => resolve(false));
      });
      
      if (compressed) {
        return c.body;
      }
      
      // 再尝试 sirv 中间件处理静态文件
      const served = await new Promise((resolve) => {
        sirvMiddleware(req, res, () => resolve(false));
      });
      
      if (served) {
        return c.body;
      }
    }

    // 处理所有其他请求的 SSR 逻辑
    /** @type {string} */
    let template;
    /** @type {import('./src/server/index.tsx').render} */
    let render;
    
    if (!isProduction && vite) {
      // 开发环境：读取最新模板并转换
      template = await fs.readFile('./index.html', 'utf-8');
      template = await vite.transformIndexHtml(normalizedUrl, template);
      render = (await vite.ssrLoadModule('/src/server/index.tsx')).render;
    } else {
      // 生产环境：使用缓存的模板
      template = templateHtml;
      render = (await import('./dist/server/entry-server.js')).render;
    }

    let didError = false;
    let abortController;

    // 创建一个可读流用于 SSR 渲染内容
    const [htmlStart, htmlEnd] = template.split(`<!--app-html-->`);
    const ssrStream = new Readable({ read: () => {} });
    
    // 写入 HTML 头部
    ssrStream.push(htmlStart);

    // 设置响应头和状态码
    c.header('Content-Type', 'text/html');
    
    // 处理渲染
    const { pipe, abort } = render(normalizedUrl, {
      onShellError() {
        didError = true;
        c.status(500);
        ssrStream.push('<h1>Something went wrong</h1>');
        ssrStream.push(null); // 结束流
      },
      onShellReady() {
        // 将渲染结果通过管道传入 ssrStream
        const transformStream = new Transform({
          transform(chunk, encoding, callback) {
            ssrStream.push(chunk, encoding);
            callback();
          }
        });

        pipe(transformStream);
        
        // 当 transformStream 完成时，添加 HTML 尾部
        transformStream.on('finish', () => {
          ssrStream.push(htmlEnd);
          ssrStream.push(null); // 结束流
        });
      },
      onError(error) {
        didError = true;
        console.error(error);
      },
    });

    // 设置超时中止
    abortController = new AbortController();
    const abortTimeout = setTimeout(() => {
      abort();
      abortController.abort();
    }, ABORT_DELAY);

    // 将流通过 Hono 响应返回
    return c.body(ssrStream, {
      onEnd: () => {
        clearTimeout(abortTimeout);
      }
    });

  } catch (e) {
    if (!isProduction && vite) {
      vite.ssrFixStacktrace(e);
    }
    console.error(e.stack);
    return c.text(e.stack, 500);
  }
});