const { Signer } = require('@volcengine/openapi');
const fetch = require('node-fetch');
const { AccessToken, privileges } = require('../lib/token');

class VolcengineService {
  constructor() {
    this.baseUrl = 'https://rtc.volcengineapi.com';
    this.service = 'rtc';
    this.region = 'cn-north-1';
    this.version = '2024-12-01';
  }

  async startVoiceChat(config) {
    console.log('[Volcengine] Starting voice chat (S2S端到端 + LLM混合, API v2024-12-01)');
    console.log('[Volcengine] RoomId:', config.RoomId);
    // ProviderParams 可能是 JSON 字符串或对象
    let pp = config.Config.S2SConfig?.ProviderParams;
    if (typeof pp === 'string') {
      try { pp = JSON.parse(pp); } catch (e) { pp = {}; }
    }
    console.log('[Volcengine] S2S AppId:', pp?.app?.appid);
    console.log('[Volcengine] S2S model:', pp?.dialog?.extra?.model);
    console.log('[Volcengine] S2S speaker:', pp?.tts?.speaker);
    console.log('[Volcengine] ProviderParams type:', typeof config.Config.S2SConfig?.ProviderParams);
    console.log('[Volcengine] LLM EndPointId:', config.Config.LLMConfig?.EndPointId);
    console.log('[Volcengine] Tools:', config.Config.LLMConfig?.Tools?.length || 0);
    console.log('[Volcengine] Full request body:', JSON.stringify(config, null, 2));
    const result = await this._callOpenAPI('StartVoiceChat', config);
    console.log('[Volcengine] StartVoiceChat response:', JSON.stringify(result, null, 2));
    return result;
  }

  async updateVoiceChat(params) {
    console.log('[Volcengine] Updating voice chat (v2024-12-01)');
    console.log('[Volcengine] UpdateVoiceChat params:', JSON.stringify(params, null, 2));
    const result = await this._callOpenAPI('UpdateVoiceChat', params);
    console.log('[Volcengine] UpdateVoiceChat response:', JSON.stringify(result, null, 2));
    return result;
  }

  async stopVoiceChat(params) {
    console.log('[Volcengine] Stopping voice chat, RoomId:', params.RoomId);
    return this._callOpenAPI('StopVoiceChat', params);
  }

  /**
   * 生成 RTC 入房 Token
   * 使用官方 AccessToken 库：https://github.com/volcengine/rtc-aigc-demo/blob/main/Server/token.js
   */
  generateRTCToken(roomId, userId) {
    const appId = process.env.VOLC_RTC_APP_ID;
    const appKey = process.env.VOLC_RTC_APP_KEY;

    if (!appId || !appKey || appKey === 'your_rtc_app_key') {
      console.warn('[Volcengine] RTC AppKey not configured, returning placeholder token');
      return `placeholder_token_${roomId}_${userId}_${Date.now()}`;
    }

    const token = new AccessToken(appId, appKey, roomId, userId);
    const expireTime = Math.floor(Date.now() / 1000) + 24 * 3600; // 24 小时有效
    token.expireTime(expireTime);
    token.addPrivilege(privileges.PrivPublishStream, 0);
    token.addPrivilege(privileges.PrivSubscribeStream, 0);

    const serialized = token.serialize();
    console.log(`[Volcengine] RTC Token generated for room=${roomId}, user=${userId}`);
    return serialized;
  }

  async _callOpenAPI(action, body, versionOverride) {
    const ak = process.env.VOLC_ACCESS_KEY_ID;
    const sk = process.env.VOLC_SECRET_ACCESS_KEY;
    const version = versionOverride || this.version;

    if (!ak || !sk || ak === 'your_access_key_id') {
      console.warn(`[Volcengine] Credentials not configured, returning mock response for ${action}`);
      return this._mockResponse(action, body);
    }

    // 与官方 rtc-aigc-demo 完全一致的签名方式
    const openApiRequestData = {
      region: this.region,
      method: 'POST',
      params: {
        Action: action,
        Version: version,
      },
      headers: {
        Host: 'rtc.volcengineapi.com',
        'Content-type': 'application/json',
      },
      body,
    };

    const signer = new Signer(openApiRequestData, this.service);
    signer.addAuthorization({ accessKeyId: ak, secretKey: sk });

    const url = `${this.baseUrl}?Action=${action}&Version=${version}`;
    console.log(`[Volcengine] ${action} calling:`, url);

    try {
      const response = await fetch(url, {
        method: 'POST',
        headers: openApiRequestData.headers,
        body: JSON.stringify(body),
      });
      const data = await response.json();

      if (data?.ResponseMetadata?.Error) {
        const err = data.ResponseMetadata.Error;
        throw new Error(`${action} failed: ${err.Code} - ${err.Message}`);
      }
      return data;
    } catch (error) {
      console.error(`[Volcengine] ${action} error:`, error.message);
      throw error;
    }
  }

  /**
   * Mock 响应（开发阶段凭证未配置时使用）
   */
  _mockResponse(action, params) {
    console.log(`[Volcengine][MOCK] ${action} called with:`, JSON.stringify(params, null, 2).substring(0, 500));
    return {
      ResponseMetadata: { RequestId: `mock-${Date.now()}`, Action: action },
      Result: { Message: 'Mock response - credentials not configured' },
    };
  }
}

module.exports = new VolcengineService();