// DeepSeek API 客户端
const DEEPSEEK_API_KEY = process.env.DEEPSEEK_API_KEY || '';

function sanitizeUserId(username) {
  return username.replace(/[^a-zA-Z0-9\-_]/g, '_').substring(0, 64) || 'anon';
}

function getErrorMsg(status, data) {
  var msg = data && data.error && data.error.message ? data.error.message : '';
  switch (status) {
    case 400: return 'AI 请求格式错误，请联系管理员(400)' + (msg ? '：' + msg : '');
    case 401: return 'AI 认证失败，请检查 API Key(401)' + (msg ? '：' + msg : '');
    case 402: return 'AI 账户余额不足，请联系管理员充值(402)';
    case 422: return 'AI 参数错误(422)' + (msg ? '：' + msg : '');
    case 429: return 'AI 请求太频繁，请稍后重试(429)';
    case 500: return 'AI 服务器故障，请稍后重试(500)';
    case 503: return 'AI 服务器繁忙，请稍后重试(503)';
    default: return 'AI 响应异常(' + status + ')' + (msg ? '：' + msg : '');
  }
}

async function callDeepSeek(messages, userId, temperature = 0.1, jsonMode = true) {
  console.log('调用 DeepSeek...');
  var body = { model: 'deepseek-v4-flash', messages: messages, temperature: temperature, stream: false, thinking: { type: 'disabled' } };
  if (jsonMode) body.response_format = { type: 'json_object' };
  if (userId) body.user_id = sanitizeUserId(userId);
  var res = await fetch('https://api.deepseek.com/chat/completions', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json', 'Authorization': 'Bearer ' + DEEPSEEK_API_KEY },
    body: JSON.stringify(body)
  });
  var data = await res.json();
  if (!res.ok) {
    var errMsg = getErrorMsg(res.status, data);
    console.error('DeepSeek API 错误:', errMsg);
    throw new Error(errMsg);
  }
  if (!data.choices || !data.choices[0]) {
    console.error('DeepSeek 返回异常:', JSON.stringify(data));
    throw new Error('AI 返回数据异常');
  }
  return data.choices[0].message.content;
}

module.exports = { callDeepSeek };