audio_codebuddy/server/src/modules/tts/aliyun.provider.ts

import axios from 'axios';
import fs from 'fs';
import path from 'path';
import { config } from '../../config';
import { VoiceParams } from '../../types';

/**
 * 阿里云百炼 Qwen-TTS Provider（同步模式）
 *
 * 接口限制参考:
 *   - Qwen-TTS (multimodal-generation): 单次 20,000 字符（同步/流式）
 *   - CosyVoice (SpeechSynthesizer): 单次 20,000 字符（同步/流式）
 *   - 传统长文本合成: 80,000 字符（建议 40,000 以内）
 *   - 传统基础合成: 300 字符（已弃用）
 *
 * 调用方式:
 *   - 同步非流式: POST → 直接返回音频 URL
 *   - SSE 流式: 加 X-DashScope-SSE: enable header
 *   - ⚠️ 不支持 X-DashScope-Async 异步模式
 *
 * 当前策略: 使用同步模式 + 1000 字符分段，每段快速返回音频 URL
 *
 * 文档: https://help.aliyun.com/zh/model-studio/qwen-tts
 */
export class AliyunTtsProvider {
  private apiKey: string;
  private model: string;
  private voice: string;
  private baseUrl = 'https://dashscope.aliyuncs.com/api/v1/services/aigc/multimodal-generation/generation';

  constructor() {
    this.apiKey = config.dashscope.apiKey;
    this.model = config.dashscope.model;
    this.voice = config.dashscope.voice;
  }

  /**
   * 语音合成（同步模式：直接返回音频 URL → 下载）
   */
  async synthesize(
    text: string,
    voiceId: string,
    params: VoiceParams,
    outputPath: string,
    retries: number = 3,
    modelOverride?: string,
  ): Promise<string> {
    const activeModel = modelOverride || this.model;
    let lastError: Error | null = null;

    for (let attempt = 1; attempt <= retries; attempt++) {
      try {
        // 构建请求体
        const requestBody: any = {
          model: activeModel,
          input: {
            text: text,
            voice: voiceId || this.voice,
            language_type: 'Chinese',
          },
        };

        // 使用 instruct 模型时支持指令控制
        if (activeModel.includes('instruct')) {
          const instructions: string[] = [];
          if (params.speed !== 1) {
            const speedDesc = params.speed > 1 ? '较快' : '较慢';
            instructions.push(`语速${speedDesc}`);
          }
          if (params.pitch !== 0) {
            const pitchDesc = params.pitch > 0 ? '较高' : '较低';
            instructions.push(`音调${pitchDesc}`);
          }
          if (instructions.length > 0) {
            requestBody.input.instructions = instructions.join('，');
          }
        }

        console.log(`📤 [Aliyun TTS] 尝试 ${attempt}/${retries}, model: ${activeModel}, voice: ${voiceId || this.voice}, text length: ${text.length}`);

        // 同步调用（不加 X-DashScope-Async，Qwen-TTS 不支持异步模式）
        const response = await axios.post(this.baseUrl, requestBody, {
          headers: {
            'Authorization': `Bearer ${this.apiKey}`,
            'Content-Type': 'application/json',
          },
          timeout: 60000,
        });

        // 检查响应
        if (response.status !== 200) {
          throw new Error(`Aliyun TTS 请求失败: HTTP ${response.status}`);
        }

        const data = response.data;
        if (data.code) {
          throw new Error(`Aliyun TTS 错误: ${data.message || JSON.stringify(data)}`);
        }

        // 获取音频 URL（同步模式直接在 output.audio.url 中返回）
        const audioUrl = data.output?.audio?.url;
        if (!audioUrl) {
          throw new Error(`Aliyun TTS 未返回音频 URL: ${JSON.stringify(data).substring(0, 200)}`);
        }

        console.log(`🔗 [Aliyun TTS] 获取音频 URL: ${audioUrl.substring(0, 80)}...`);

        // 下载音频文件
        try {
          return await this.downloadAudio(audioUrl, outputPath);
        } catch (downloadError: any) {
          console.warn(`⚠️ [Aliyun TTS] 音频下载失败: ${downloadError.message}`);
          // 下载失败，返回 cloud: URL 标记（后续会处理）
          return `cloud:${audioUrl}`;
        }
      } catch (error: any) {
        const errorDetails = error.response?.data || error.message;
        const isRateLimit = error.response?.status === 429 || errorDetails?.code === 'Throttling.RateQuota';
        const isServerError = error.response?.status >= 500;

        console.error(`❌ [Aliyun TTS] 失败 (尝试 ${attempt}/${retries}):`, error.message);

        if ((isRateLimit || isServerError) && attempt < retries) {
          const waitTime = Math.pow(2, attempt) * 1000;
          console.warn(`⏳ 等待 ${waitTime}ms 后重试...`);
          await new Promise(resolve => setTimeout(resolve, waitTime));
          lastError = new Error(`Aliyun TTS 临时错误: ${error.message}`);
          continue;
        }

        lastError = new Error(`Aliyun TTS 调用失败: ${error.message}`);
      }
    }

    throw lastError || new Error('Aliyun TTS 服务调用失败');
  }

  /**
   * 下载音频文件到本地
   */
  private async downloadAudio(audioUrl: string, outputPath: string): Promise<string> {
    console.log(`⬇️ [Aliyun TTS] 下载音频: ${audioUrl.substring(0, 80)}...`);

    const response = await axios.get(audioUrl, {
      responseType: 'arraybuffer',
      timeout: 120000,
    });

    const dir = path.dirname(outputPath);
    if (!fs.existsSync(dir)) {
      fs.mkdirSync(dir, { recursive: true });
    }

    // 确保输出路径以 .wav 结尾（Qwen-TTS 返回 wav 格式）
    const finalPath = outputPath.endsWith('.wav') ? outputPath : outputPath.replace(/\.[^.]+$/, '.wav');
    fs.writeFileSync(finalPath, response.data);
    const stats = fs.statSync(finalPath);
    console.log(`✅ [Aliyun TTS] 下载完成: ${finalPath} (${stats.size} bytes)`);

    return finalPath;
  }
}