const { v4: uuidv4 } = require('uuid');

class VoiceChatConfigBuilder {
  /**
   * 构建 StartVoiceChat 的完整配置（S2S 端到端语音大模型 + LLM 混合编排）
   * OutputMode=1: 混合模式，S2S 处理普通对话，LLM 处理工具调用
   */
  static build(options) {
    const {
      roomId,
      taskId,
      userId,
      botName = '小智',
      systemRole = '你是一个友善的智能助手。',
      speakingStyle = '请使用温和、清晰的口吻。',
      modelVersion = '1.2.1.0',
      speaker = 'zh_female_vv_jupiter_bigtts',
      tools = [],
      llmSystemPrompt = '',
      enableWebSearch = false,
      vadEndMs = 1200,
      chatHistory = [],
    } = options;

    const botUserId = `bot_${uuidv4().slice(0, 8)}`;

    const providerParams = {
      app: {
        appid: process.env.VOLC_S2S_APP_ID,
        token: process.env.VOLC_S2S_TOKEN,
      },
      dialog: this._buildDialogConfig(modelVersion, botName, systemRole, speakingStyle, enableWebSearch, chatHistory),
      tts: {
        speaker: speaker,
      },
      asr: {
        extra: {
          enable_custom_vad: true,
          end_smooth_window_ms: vadEndMs,
        },
      },
    };

    // === 调试模式：纯 S2S（OutputMode=0），排除 LLM 干扰 ===
    // ARK 端点已配置正确，启用混合编排模式
    const DEBUG_PURE_S2S = false;

    const llmConfig = {
      Mode: 'ArkV3',
      EndPointId: process.env.VOLC_ARK_ENDPOINT_ID,
      MaxTokens: 1024,
      Temperature: 0.1,
      TopP: 0.3,
      SystemMessages: [llmSystemPrompt || this._buildDefaultLLMPrompt(tools)],
      HistoryLength: 10,
      ThinkingType: 'disabled',
    };
    if (tools.length > 0) {
      llmConfig.Tools = tools;
    }

    // 混合模式：通过 UserPrompts 传入聊天历史作为上下文（官方推荐方式）
    if (chatHistory && chatHistory.length > 0 && !DEBUG_PURE_S2S) {
      const userPrompts = chatHistory.slice(-10).map(m => ({
        Role: m.role === 'user' ? 'user' : 'assistant',
        Content: m.content,
      }));
      llmConfig.UserPrompts = userPrompts;
      console.log(`[VoiceChatConfig] Injected ${userPrompts.length} UserPrompts into LLMConfig`);
    }

    const config = {
      AppId: process.env.VOLC_RTC_APP_ID,
      RoomId: roomId,
      TaskId: taskId,
      AgentConfig: {
        TargetUserId: [userId],
        WelcomeMessage: `你好，我是${botName}，有什么需要帮忙的吗？`,
        UserId: botUserId,
        EnableConversationStateCallback: true,
      },
      Config: {
        S2SConfig: {
          Provider: 'volcano',
          OutputMode: DEBUG_PURE_S2S ? 0 : 1,
          ProviderParams: providerParams,
        },
        // 注意：S2S 端到端模式下不需要独立 TTSConfig
        // ExternalTextToSpeech 在 S2S 模式下不产生音频，只用 Command:function
        SubtitleConfig: {
          SubtitleMode: 1,
        },
        InterruptMode: 0,
      },
    };

    // 混合模式才需要 LLMConfig
    if (!DEBUG_PURE_S2S) {
      config.Config.LLMConfig = llmConfig;

      // Function Calling 回调配置：RTC 服务通过此 URL 发送 tool call 请求
      if (tools.length > 0) {
        const serverUrl = process.env.FC_SERVER_URL || 'https://demo.tensorgrove.com.cn/api/voice/fc_callback';
        config.Config.FunctionCallingConfig = {
          ServerMessageUrl: serverUrl,
          ServerMessageSignature: process.env.FC_SIGNATURE || 'default_signature',
        };
        console.log(`[VoiceChatConfig] FunctionCallingConfig enabled, URL: ${serverUrl}`);
      }
    }

    console.log('[VoiceChatConfig] DEBUG_PURE_S2S:', DEBUG_PURE_S2S);
    console.log('[VoiceChatConfig] OutputMode:', config.Config.S2SConfig.OutputMode);
    console.log('[VoiceChatConfig] ProviderParams type:', typeof config.Config.S2SConfig.ProviderParams);
    console.log('[VoiceChatConfig] S2S AppId:', providerParams.app.appid);
    console.log('[VoiceChatConfig] S2S Token:', providerParams.app.token ? '***set***' : '***MISSING***');

    return { config, botUserId };
  }

  static _buildDialogConfig(modelVersion, botName, systemRole, speakingStyle, enableWebSearch, chatHistory = []) {
    const isOSeries = modelVersion === 'O' || modelVersion.startsWith('1.');
    const dialog = {
      extra: { model: modelVersion },
    };

    // 如果有文字聊天历史，将其追加到 system_role 作为上下文
    let fullSystemRole = systemRole;
    if (chatHistory && chatHistory.length > 0) {
      const historyText = chatHistory
        .slice(-10)
        .map(m => `${m.role === 'user' ? '用户' : '助手'}：${m.content}`)
        .join('\n');
      fullSystemRole += `\n\n## 之前的对话记录（请延续此上下文）\n${historyText}`;
      console.log(`[VoiceChatConfig] Injected ${chatHistory.length} chat history messages into system_role`);
    }

    if (isOSeries) {
      dialog.bot_name = botName;
      dialog.system_role = fullSystemRole;
      dialog.speaking_style = speakingStyle;
    } else {
      dialog.character_manifest = `${fullSystemRole}\n你的名字是${botName}。${speakingStyle}`;
    }

    if (enableWebSearch && process.env.VOLC_WEBSEARCH_API_KEY) {
      dialog.extra.enable_volc_websearch = true;
      dialog.extra.volc_websearch_api_key = process.env.VOLC_WEBSEARCH_API_KEY;
      dialog.extra.volc_websearch_type = 'web_summary';
      dialog.extra.volc_websearch_no_result_message = '抱歉，我没有查到相关信息。';
    }

    return dialog;
  }

  static _buildDefaultLLMPrompt(tools) {
    const toolNames = tools.map((t) => t.function?.name).filter(Boolean);
    if (toolNames.length === 0) {
      return '你是一个智能助手。对于所有问题直接回答即可。';
    }
    return `你是一个企业智能客服助手。你可以使用以下工具：${toolNames.join('、')}。

## 最高优先级规则
1. 每次用户提问，你**必须**先调用 search_knowledge 工具查询知识库
2. 收到工具返回的知识库内容后，你**必须完整、详细地朗读**知识库返回的内容给用户
3. 不要省略、总结或缩写知识库的内容，要逐字朗读
4. 如果知识库没有相关内容，再用你自己的知识简洁回答
5. 如果知识库返回"未找到相关信息"，直接告诉用户并提供建议`;
  }
}

module.exports = VoiceChatConfigBuilder;