/**
 * Phase II — 意图处理器（Intent Handlers）
 *
 * 按意图类型分发处理逻辑：
 *   - chat:     直接 LLM 对话
 *   - explore:  READ 工具 + LLM 解读
 *   - analyze:  转入 QPER 流水线 + LLM 摘要
 *   - consult:  LLM 方法推荐（Phase III 增强）
 *   - discuss:  LLM 结果解读（Phase V 增强）
 *   - feedback: LLM 改进建议（Phase V 增强）
 */

import { logger } from '../../../common/logging/index.js';
import { conversationService, type StreamWriter } from './ConversationService.js';
import { sessionBlackboardService } from './SessionBlackboardService.js';
import { tokenTruncationService } from './TokenTruncationService.js';
import { methodConsultService } from './MethodConsultService.js';
import { askUserService, type AskUserResponse } from './AskUserService.js';
import { toolOrchestratorService } from './ToolOrchestratorService.js';
import type { IntentType } from './SystemPromptService.js';
import type { IntentResult } from './IntentRouterService.js';

export interface HandleResult {
  messageId: string;
  intent: IntentType;
  success: boolean;
  error?: string;
}

export class ChatHandlerService {

  /**
   * 统一处理入口：按意图分发
   */
  async handle(
    sessionId: string,
    conversationId: string,
    userContent: string,
    intentResult: IntentResult,
    writer: StreamWriter,
    placeholderMessageId: string,
  ): Promise<HandleResult> {
    const intent = intentResult.intent;

    try {
      // 如果上下文守卫被触发且有提示消息，直接作为 LLM 上下文的一部分
      let toolOutputs: string | undefined;

      if (intentResult.guardTriggered && intentResult.guardMessage) {
        toolOutputs = `[系统提示] ${intentResult.guardMessage}`;
      }

      switch (intent) {
        case 'chat':
          return await this.handleChat(sessionId, conversationId, writer, placeholderMessageId, intent, toolOutputs);

        case 'explore':
          return await this.handleExplore(sessionId, conversationId, writer, placeholderMessageId, toolOutputs);

        case 'consult':
          return await this.handleConsult(sessionId, conversationId, writer, placeholderMessageId, toolOutputs);

        case 'analyze':
          return await this.handleAnalyze(sessionId, conversationId, userContent, writer, placeholderMessageId, toolOutputs);

        case 'discuss':
          return await this.handleDiscuss(sessionId, conversationId, writer, placeholderMessageId, toolOutputs);

        case 'feedback':
          return await this.handleChat(sessionId, conversationId, writer, placeholderMessageId, 'feedback', toolOutputs);

        default:
          return await this.handleChat(sessionId, conversationId, writer, placeholderMessageId, 'chat', toolOutputs);
      }
    } catch (error: any) {
      logger.error('[SSA:ChatHandler] Handler error', {
        sessionId, intent, error: error.message,
      });

      await conversationService.markAssistantError(placeholderMessageId, error.message);

      return {
        messageId: placeholderMessageId,
        intent,
        success: false,
        error: error.message,
      };
    }
  }

  // ────────────────────────────────────────────
  // chat / consult / feedback — 直接 LLM 对话
  // ────────────────────────────────────────────

  private async handleChat(
    sessionId: string,
    conversationId: string,
    writer: StreamWriter,
    placeholderMessageId: string,
    intent: IntentType,
    toolOutputs?: string,
  ): Promise<HandleResult> {
    const messages = await conversationService.buildContext(
      sessionId, conversationId, intent, toolOutputs,
    );

    const result = await conversationService.streamToSSE(messages, writer, {
      temperature: 0.7,
      maxTokens: 2000,
    });

    await conversationService.finalizeAssistantMessage(
      placeholderMessageId, result.content, result.thinking, result.tokens,
    );

    return {
      messageId: placeholderMessageId,
      intent,
      success: true,
    };
  }

  // ────────────────────────────────────────────
  // explore — 数据探索（READ 工具 + LLM 解读）
  // ────────────────────────────────────────────

  private async handleExplore(
    sessionId: string,
    conversationId: string,
    writer: StreamWriter,
    placeholderMessageId: string,
    guardToolOutput?: string,
  ): Promise<HandleResult> {
    // 从 SessionBlackboard 提取数据摘要作为 tool output
    const blackboard = await sessionBlackboardService.get(sessionId);
    let toolOutputs = guardToolOutput || '';

    if (blackboard) {
      const truncated = tokenTruncationService.truncate(blackboard, {
        maxTokens: 1500,
        strategy: 'balanced',
      });

      const exploreData: string[] = [];

      if (truncated.overview) {
        exploreData.push(`数据概览:\n${truncated.overview}`);
      }
      if (truncated.variables) {
        exploreData.push(`变量列表:\n${truncated.variables}`);
      }
      if (truncated.pico) {
        exploreData.push(`PICO 推断:\n${truncated.pico}`);
      }
      if (truncated.report) {
        exploreData.push(`数据诊断:\n${truncated.report}`);
      }

      if (exploreData.length > 0) {
        toolOutputs = (toolOutputs ? toolOutputs + '\n\n' : '') + exploreData.join('\n\n');
      }
    }

    const messages = await conversationService.buildContext(
      sessionId, conversationId, 'explore', toolOutputs || undefined,
    );

    const result = await conversationService.streamToSSE(messages, writer, {
      temperature: 0.7,
      maxTokens: 2000,
    });

    await conversationService.finalizeAssistantMessage(
      placeholderMessageId, result.content, result.thinking, result.tokens,
    );

    return {
      messageId: placeholderMessageId,
      intent: 'explore',
      success: true,
    };
  }

  // ────────────────────────────────────────────
  // analyze — 转入 QPER（混合模式：LLM 摘要 + WorkspacePane 详情）
  // ────────────────────────────────────────────

  /**
   * Phase IV: analyze 意图 — 对话驱动分析
   *
   * 流程: plan 生成 → SSE 推 analysis_plan → LLM 方案说明 → ask_user 确认
   * 执行由前端通过 /workflow/{id}/stream 触发（D1: 保留独立 workflow SSE）
   */
  private async handleAnalyze(
    sessionId: string,
    conversationId: string,
    userMessage: string,
    writer: StreamWriter,
    placeholderMessageId: string,
    guardToolOutput?: string,
  ): Promise<HandleResult> {
    // 1. 调用 ToolOrchestratorService 生成计划（D5: PICO hint 自动注入）
    const planResult = await toolOrchestratorService.plan(sessionId, userMessage);

    if (!planResult.success || !planResult.plan) {
      const fallbackHint = [
        guardToolOutput,
        `[系统提示] 分析计划生成失败: ${planResult.error || '未知错误'}。`,
        '请友好地告知用户需要更明确的分析需求描述，例如需要指明要分析哪些变量、比较什么。',
      ].filter(Boolean).join('\n');

      const messages = await conversationService.buildContext(
        sessionId, conversationId, 'analyze', fallbackHint,
      );
      const result = await conversationService.streamToSSE(messages, writer, {
        temperature: 0.5, maxTokens: 800,
      });
      await conversationService.finalizeAssistantMessage(
        placeholderMessageId, result.content, result.thinking, result.tokens,
      );
      return { messageId: placeholderMessageId, intent: 'analyze', success: true };
    }

    const plan = planResult.plan;

    // 2. SSE 推送 analysis_plan 事件（D2: 前端自动创建 AnalysisRecord）
    const planEvent = `data: ${JSON.stringify({
      type: 'analysis_plan',
      plan,
    })}\n\n`;
    writer.write(planEvent);

    logger.info('[SSA:ChatHandler] analysis_plan pushed via SSE', {
      sessionId, workflowId: plan.workflow_id, totalSteps: plan.total_steps,
    });

    // 3. LLM 流式生成方案说明
    const planSummary = toolOrchestratorService.formatPlanForLLM(plan);
    const toolOutputs = [
      guardToolOutput,
      planSummary,
      '[系统提示] 你刚刚为用户制定了上述分析方案。请用自然语言向用户解释这个方案：包括为什么选这些方法、分析步骤的逻辑。不要重复列步骤编号和工具代码，要用用户能理解的语言说明。最后提示用户确认方案后即可执行。',
    ].filter(Boolean).join('\n\n');

    const messages = await conversationService.buildContext(
      sessionId, conversationId, 'analyze', toolOutputs,
    );

    const result = await conversationService.streamToSSE(messages, writer, {
      temperature: 0.5, maxTokens: 1200,
    });

    await conversationService.finalizeAssistantMessage(
      placeholderMessageId, result.content, result.thinking, result.tokens,
    );

    // 4. 推送 ask_user 确认卡片（复用 Phase III AskUserService）
    const confirmQ = {
      inputType: 'confirm' as const,
      question: '请确认上述分析方案',
      context: `方案: ${plan.title}，共 ${plan.total_steps} 个步骤`,
      options: [
        { id: 'confirm_plan', label: '确认执行', value: 'confirm_plan' },
        { id: 'change_method', label: '修改方案', value: 'change_method' },
      ],
      metadata: {
        workflowId: plan.workflow_id,
        planTitle: plan.title,
      },
    };

    const event = await askUserService.createQuestion(sessionId, confirmQ);
    writer.write(askUserService.formatSSE(event));

    return {
      messageId: placeholderMessageId,
      intent: 'analyze',
      success: true,
    };
  }

  // ────────────────────────────────────────────
  // discuss — 结果讨论（注入分析结果上下文）
  // ────────────────────────────────────────────

  private async handleDiscuss(
    sessionId: string,
    conversationId: string,
    writer: StreamWriter,
    placeholderMessageId: string,
    guardToolOutput?: string,
  ): Promise<HandleResult> {
    const blackboard = await sessionBlackboardService.get(sessionId);
    let toolOutputs = guardToolOutput || '';

    // 注入 QPER trace 摘要
    if (blackboard?.qperTrace && blackboard.qperTrace.length > 0) {
      const traceItems = blackboard.qperTrace
        .filter(t => t.status === 'success')
        .slice(-5)
        .map(t => `- 步骤${t.stepIndex}: ${t.toolCode} → ${t.summary}`)
        .join('\n');

      if (traceItems) {
        toolOutputs = (toolOutputs ? toolOutputs + '\n\n' : '') +
          `最近分析结果:\n${traceItems}`;
      }
    }

    const messages = await conversationService.buildContext(
      sessionId, conversationId, 'discuss', toolOutputs || undefined,
    );

    const result = await conversationService.streamToSSE(messages, writer, {
      temperature: 0.7,
      maxTokens: 2000,
    });

    await conversationService.finalizeAssistantMessage(
      placeholderMessageId, result.content, result.thinking, result.tokens,
    );

    return {
      messageId: placeholderMessageId,
      intent: 'discuss',
      success: true,
    };
  }

  // ────────────────────────────────────────────
  // consult — 方法推荐（Phase III: method_consult + ask_user）
  // ────────────────────────────────────────────

  private async handleConsult(
    sessionId: string,
    conversationId: string,
    writer: StreamWriter,
    placeholderMessageId: string,
    guardToolOutput?: string,
  ): Promise<HandleResult> {
    let toolOutputs = guardToolOutput || '';

    // 1. 调用 MethodConsultService 获取推荐
    const recommendation = await methodConsultService.recommend(sessionId);
    const recText = methodConsultService.formatForLLM(recommendation);
    toolOutputs = (toolOutputs ? toolOutputs + '\n\n' : '') + recText;

    logger.info('[SSA:ChatHandler] Method consult result', {
      sessionId,
      matched: recommendation.matched,
      primaryMethod: recommendation.primaryMethod?.code,
      matchScore: recommendation.matchScore,
      needsClarification: recommendation.needsClarification,
    });

    // 2. LLM 生成自然语言推荐（P1: 结论先行 + 结构化列表）
    const messages = await conversationService.buildContext(
      sessionId, conversationId, 'consult', toolOutputs,
    );

    const result = await conversationService.streamToSSE(messages, writer, {
      temperature: 0.5,
      maxTokens: 1500,
    });

    await conversationService.finalizeAssistantMessage(
      placeholderMessageId, result.content, result.thinking, result.tokens,
    );

    // 3. 如果有明确推荐，推送 ask_user 确认卡片
    if (recommendation.matched && recommendation.primaryMethod) {
      const confirmQ = askUserService.buildMethodConfirmQuestion(
        recommendation.primaryMethod.name,
        recommendation.primaryMethod.code,
        recommendation.fallbackMethod?.name,
      );

      const event = await askUserService.createQuestion(sessionId, confirmQ);
      writer.write(askUserService.formatSSE(event));
    }

    return {
      messageId: placeholderMessageId,
      intent: 'consult',
      success: true,
    };
  }

  // ────────────────────────────────────────────
  // ask_user 响应处理（Phase III）
  // ────────────────────────────────────────────

  async handleAskUserResponse(
    sessionId: string,
    conversationId: string,
    response: AskUserResponse,
    writer: StreamWriter,
    placeholderMessageId: string,
  ): Promise<HandleResult> {
    // 清除 pending 状态
    await askUserService.clearPending(sessionId);

    if (response.action === 'skip') {
      // 用户跳过 — 生成友好回复
      const messages = await conversationService.buildContext(
        sessionId, conversationId, 'chat',
        '[系统提示] 用户跳过了上一个确认问题。请友好地回应，表示随时可以继续。',
      );

      const result = await conversationService.streamToSSE(messages, writer, {
        temperature: 0.7,
        maxTokens: 500,
      });

      await conversationService.finalizeAssistantMessage(
        placeholderMessageId, result.content, result.thinking, result.tokens,
      );

      return { messageId: placeholderMessageId, intent: 'chat', success: true };
    }

    // 用户选择了具体选项
    const selectedValue = response.selectedValues?.[0];

    if (selectedValue === 'confirm_plan') {
      // Phase IV: 确认分析方案 → 前端将触发 executeWorkflow
      const workflowId = response.metadata?.workflowId || '';
      const messages = await conversationService.buildContext(
        sessionId, conversationId, 'analyze',
        `[系统提示] 用户已确认分析方案（workflow: ${workflowId}）。请简要确认："好的，方案已确认，正在准备执行分析..."。`,
      );

      const result = await conversationService.streamToSSE(messages, writer, {
        temperature: 0.3, maxTokens: 300,
      });

      await conversationService.finalizeAssistantMessage(
        placeholderMessageId, result.content, result.thinking, result.tokens,
      );

      // 推送 plan_confirmed 事件，前端据此触发 executeWorkflow
      const confirmEvent = `data: ${JSON.stringify({
        type: 'plan_confirmed',
        workflowId,
      })}\n\n`;
      writer.write(confirmEvent);

      return { messageId: placeholderMessageId, intent: 'analyze', success: true };

    } else if (selectedValue === 'confirm') {
      // Phase III: 确认使用推荐方法 → 提示可以开始分析
      const messages = await conversationService.buildContext(
        sessionId, conversationId, 'analyze',
        '[系统提示] 用户已确认使用推荐的统计方法。请简要确认方案，告知用户可以在对话中说"开始分析"或在右侧面板触发执行。',
      );

      const result = await conversationService.streamToSSE(messages, writer, {
        temperature: 0.5,
        maxTokens: 800,
      });

      await conversationService.finalizeAssistantMessage(
        placeholderMessageId, result.content, result.thinking, result.tokens,
      );

      return { messageId: placeholderMessageId, intent: 'analyze', success: true };

    } else if (selectedValue === 'use_fallback') {
      // 使用备选方案
      const messages = await conversationService.buildContext(
        sessionId, conversationId, 'consult',
        '[系统提示] 用户选择使用备选方案。请确认切换，并简要说明备选方案的适用场景。',
      );

      const result = await conversationService.streamToSSE(messages, writer, {
        temperature: 0.5,
        maxTokens: 800,
      });

      await conversationService.finalizeAssistantMessage(
        placeholderMessageId, result.content, result.thinking, result.tokens,
      );

      return { messageId: placeholderMessageId, intent: 'consult', success: true };

    } else if (selectedValue === 'change_method') {
      // 用户想换方法 → 引导重新描述
      const messages = await conversationService.buildContext(
        sessionId, conversationId, 'consult',
        '[系统提示] 用户不满意当前推荐，想换方法。请询问用户希望使用什么方法，或引导其更详细地描述分析需求。',
      );

      const result = await conversationService.streamToSSE(messages, writer, {
        temperature: 0.7,
        maxTokens: 800,
      });

      await conversationService.finalizeAssistantMessage(
        placeholderMessageId, result.content, result.thinking, result.tokens,
      );

      return { messageId: placeholderMessageId, intent: 'consult', success: true };
    }

    // 其他情况：fallback
    return await this.handleChat(sessionId, conversationId, writer, placeholderMessageId, 'chat');
  }
}

export const chatHandlerService = new ChatHandlerService();