/**
 * http.js - HTTP 请求工具模块
 * 纯 Node.js 原生 https/http 实现，零依赖
 */

import https from 'https';
import http from 'http';
import { URL } from 'url';
import config from './config.js';

const sleep = (ms) => new Promise(r => setTimeout(r, ms));

/**
 * 通用 HTTP 请求 — 支持 cookie 管理、重定向跟踪、JSON 自动解析
 */
export async function request(url, options = {}) {
  const {
    method = 'GET',
    headers = {},
    body = null,
    timeout = config.timeout || 30000,
    followRedirect = true,
    maxRedirects = 5,
    cookies = null,
  } = options;

  const urlObj = new URL(url);
  const isHttps = urlObj.protocol === 'https:';
  const lib = isHttps ? https : http;

  const finalHeaders = {
    'User-Agent': config.userAgent,
    'Accept': 'application/json, text/html, */*',
    'Accept-Language': 'en-US,en;q=0.9,ru;q=0.8,zh-CN;q=0.7',
    'Accept-Encoding': 'identity',
    ...headers,
  };

  // 注入 cookies
  if (cookies && cookies.size > 0) {
    finalHeaders['Cookie'] = [...cookies.entries()].map(([k, v]) => `${k}=${v}`).join('; ');
  }

  // 处理 body
  let bodyStr = null;
  if (body) {
    bodyStr = typeof body === 'string' ? body : JSON.stringify(body);
    if (!finalHeaders['Content-Type']) {
      finalHeaders['Content-Type'] = 'application/json';
    }
    finalHeaders['Content-Length'] = Buffer.byteLength(bodyStr);
  }

  return new Promise((resolve, reject) => {
    const reqOptions = {
      hostname: urlObj.hostname,
      port: urlObj.port || (isHttps ? 443 : 80),
      path: urlObj.pathname + urlObj.search,
      method,
      headers: finalHeaders,
      timeout,
    };

    const req = lib.request(reqOptions, (res) => {
      // 收集 Set-Cookie
      const resCookies = new Map(cookies || []);
      const setCookieHeaders = res.headers['set-cookie'] || [];
      for (const sc of setCookieHeaders) {
        const [pair] = sc.split(';');
        const [name, ...valueParts] = pair.split('=');
        resCookies.set(name.trim(), valueParts.join('=').trim());
      }

      // 处理重定向
      if (followRedirect && [301, 302, 303, 307, 308].includes(res.statusCode) && maxRedirects > 0) {
        const location = res.headers['location'];
        if (location) {
          const redirectUrl = location.startsWith('http') ? location : new URL(location, url).href;
          res.resume(); // 丢弃 body
          resolve(request(redirectUrl, {
            ...options,
            maxRedirects: maxRedirects - 1,
            cookies: resCookies,
            method: [301, 302, 303].includes(res.statusCode) ? 'GET' : method,
            body: [301, 302, 303].includes(res.statusCode) ? null : body,
          }));
          return;
        }
      }

      let data = '';
      res.setEncoding('utf8');
      res.on('data', chunk => data += chunk);
      res.on('end', () => {
        resolve({
          ok: res.statusCode >= 200 && res.statusCode < 300,
          status: res.statusCode,
          statusText: res.statusMessage,
          headers: res.headers,
          cookies: resCookies,
          url,
          text: () => data,
          json: () => {
            try { return JSON.parse(data); }
            catch { throw new Error(`JSON parse error: ${data.substring(0, 200)}`); }
          },
          html: () => data,
        });
      });
    });

    req.on('error', reject);
    req.on('timeout', () => { req.destroy(); reject(new Error(`请求超时: ${url}`)); });

    if (bodyStr) req.write(bodyStr);
    req.end();
  });
}

/**
 * GET 请求简写
 */
export async function get(url, options = {}) {
  return request(url, { ...options, method: 'GET' });
}

/**
 * POST 请求简写
 */
export async function post(url, body, options = {}) {
  return request(url, { ...options, method: 'POST', body });
}

/**
 * 带重试的请求
 */
export async function retryRequest(url, options = {}, maxRetries = 3) {
  let lastError;
  for (let i = 0; i < maxRetries; i++) {
    try {
      const resp = await request(url, options);
      if (resp.ok || resp.status < 500) return resp;
      lastError = new Error(`HTTP ${resp.status}: ${resp.text().substring(0, 200)}`);
    } catch (e) {
      lastError = e;
    }
    if (i < maxRetries - 1) {
      const delay = 1000 * (i + 1) + Math.random() * 1000;
      console.log(`    [HTTP] 重试 ${i + 1}/${maxRetries} (${Math.round(delay)}ms)...`);
      await sleep(delay);
    }
  }
  throw lastError;
}

export { sleep };

/**
 * 流式 HTTP 请求 — 返回原始响应流 (不缓冲 body)
 * 用于代理 chataibot SSE 流式响应
 */
export async function requestStream(url, options = {}) {
  const {
    method = 'GET',
    headers = {},
    body = null,
    timeout = config.timeout || 120000,
    cookies = null,
  } = options;

  const urlObj = new URL(url);
  const isHttps = urlObj.protocol === 'https:';
  const lib = isHttps ? https : http;

  const finalHeaders = {
    'User-Agent': config.userAgent,
    'Accept': 'text/event-stream, application/json',
    'Accept-Language': 'en',
    'Accept-Encoding': 'identity',
    ...headers,
  };

  if (cookies && cookies.size > 0) {
    finalHeaders['Cookie'] = [...cookies.entries()].map(([k, v]) => `${k}=${v}`).join('; ');
  }

  let bodyStr = null;
  if (body) {
    bodyStr = typeof body === 'string' ? body : JSON.stringify(body);
    if (!finalHeaders['Content-Type']) {
      finalHeaders['Content-Type'] = 'application/json';
    }
    finalHeaders['Content-Length'] = Buffer.byteLength(bodyStr);
  }

  return new Promise((resolve, reject) => {
    const reqOptions = {
      hostname: urlObj.hostname,
      port: urlObj.port || (isHttps ? 443 : 80),
      path: urlObj.pathname + urlObj.search,
      method,
      headers: finalHeaders,
      timeout,
    };

    const req = lib.request(reqOptions, (res) => {
      const resCookies = new Map(cookies || []);
      const setCookieHeaders = res.headers['set-cookie'] || [];
      for (const sc of setCookieHeaders) {
        const [pair] = sc.split(';');
        const [name, ...valueParts] = pair.split('=');
        resCookies.set(name.trim(), valueParts.join('=').trim());
      }

      resolve({
        ok: res.statusCode >= 200 && res.statusCode < 300,
        status: res.statusCode,
        headers: res.headers,
        cookies: resCookies,
        stream: res,
      });
    });

    req.on('error', reject);
    req.on('timeout', () => { req.destroy(); reject(new Error(`流式请求超时: ${url}`)); });

    if (bodyStr) req.write(bodyStr);
    req.end();
  });
}