/**
 * 意图分类器 - 第一层
 * 快速分析用户意图，决定回复策略
 */

export enum IntentType {
  /** 简单查询 - 直接回答，无需工具 */
  SIMPLE_QUERY = 'SIMPLE_QUERY',
  /** 深度咨询 - 需要知识库检索 */
  DEEP_CONSULTATION = 'DEEP_CONSULTATION',
  /** 需要行动 - 需要调用工具执行操作 */
  ACTION_NEEDED = 'ACTION_NEEDED',
  /** 闲聊 - 简短友好回复 */
  CHAT = 'CHAT',
  /** 澄清 - 用户意图不明，需要追问 */
  CLARIFICATION = 'CLARIFICATION',
  /** 确认 - 用户确认/否定之前的回答 */
  CONFIRMATION = 'CONFIRMATION',
}

export interface IntentResult {
  type: IntentType;
  confidence: number;
  /** 建议的最大回复长度（字符数） */
  maxResponseLength: number;
  /** 是否需要调用工具 */
  needsTools: boolean;
  /** 建议使用的工具 */
  suggestedTools?: string[];
  /** 检测到的关键实体 */
  entities?: Record<string, string>;
  /** 是否为后续问题（基于上下文） */
  isFollowUp: boolean;
}

interface Message {
  role: 'user' | 'assistant';
  content: string;
}

/**
 * 意图分类器
 * 使用规则 + 关键词匹配快速分类，无需 API 调用
 */
export class IntentClassifier {
  // 简单查询关键词
  private simpleQueryPatterns = [
    /^(什么是|是什么|哪个|哪些|多少|几|怎么样|好不好)/,
    /^(请问|想问|问一下)/,
    /(是多少|要多久|需要什么|有哪些)/,
    /^(可以吗|能不能|行不行)/,
  ];

  // 深度咨询关键词
  private deepConsultationPatterns = [
    /(怎么办|如何|怎样|怎么做|该怎么)/,
    /(详细|具体|解释|说明|介绍)/,
    /(比较|对比|区别|差异)/,
    /(流程|步骤|过程|程序)/,
    /(条件|要求|资格|标准)/,
    /(材料|文件|清单|准备)/,
    /(评估|分析|建议|推荐)/,
  ];

  // 需要行动的关键词
  private actionPatterns = [
    /(帮我|帮忙|请帮|麻烦)/,
    /(查询|查一下|搜索|找一下|查找)/,
    /(计算|算一下|估算)/,
    /(预约|申请|提交|办理)/,
    /(发送|转发|通知)/,
  ];

  // 闲聊关键词
  private chatPatterns = [
    /^(你好|您好|hi|hello|嗨|早|晚)/i,
    /^(谢谢|感谢|多谢|thanks)/i,
    /^(再见|拜拜|bye|88)/i,
    /^(好的|明白|知道了|了解|收到)/,
    /(哈哈|呵呵|嘿嘿|😀|👍|🙏)/,
  ];

  // 确认/否定关键词
  private confirmationPatterns = [
    /^(是的|对|对的|没错|正确|是啊|嗯)/,
    /^(不是|不对|错了|不|否)/,
    /^(还有|另外|还想问|补充)/,
  ];

  // 工具关键词映射
  private toolKeywords: Record<string, string[]> = {
    'knowledge-search': ['知识', '文章', '政策', '规定', '信息', '资料'],
    'search-web': ['最新', '新闻', '近期', '实时', '当前', '现在'],
    'get-weather': ['天气', '温度', '下雨', '晴天'],
    'experience-recall': ['之前', '上次', '经验', '类似'],
    'user-memory-recall': ['我之前', '我上次', '我的', '记得我'],
    'immigration-assessment': ['评估', '打分', '分数', '资格'],
    'calculate': ['计算', '算', '多少钱', '费用'],
  };

  // 移民相关类别关键词
  private immigrationCategories: Record<string, string[]> = {
    'skilled-migration': ['技术移民', '189', '190', '491', '打分', '职业评估', 'EOI'],
    'employer-sponsored': ['雇主担保', '482', '494', '186', '雇主', '工签'],
    'business-investment': ['商业移民', '投资移民', '188', '132', '商业', '投资'],
    'family-reunion': ['家庭团聚', '配偶', '父母', '子女', '820', '801', '143'],
    'student-visa': ['学生签证', '500', '485', '留学', '毕业生'],
    'visitor-visa': ['旅游签', '600', '访客', '探亲'],
  };

  /**
   * 分类用户意图
   */
  classify(
    userMessage: string,
    conversationHistory: Message[] = [],
  ): IntentResult {
    const text = userMessage.trim();
    const isFollowUp = this.detectFollowUp(text, conversationHistory);

    // 1. 检测闲聊
    if (this.matchPatterns(text, this.chatPatterns)) {
      return {
        type: IntentType.CHAT,
        confidence: 0.9,
        maxResponseLength: 100,
        needsTools: false,
        isFollowUp,
      };
    }

    // 2. 检测确认/否定
    if (this.matchPatterns(text, this.confirmationPatterns) && isFollowUp) {
      return {
        type: IntentType.CONFIRMATION,
        confidence: 0.85,
        maxResponseLength: 200,
        needsTools: false,
        isFollowUp: true,
      };
    }

    // 3. 检测需要行动
    const actionTools = this.detectActionTools(text);
    if (this.matchPatterns(text, this.actionPatterns) || actionTools.length > 0) {
      return {
        type: IntentType.ACTION_NEEDED,
        confidence: 0.8,
        maxResponseLength: 500,
        needsTools: true,
        suggestedTools: actionTools.length > 0 ? actionTools : undefined,
        entities: this.extractEntities(text),
        isFollowUp,
      };
    }

    // 4. 检测深度咨询
    if (this.matchPatterns(text, this.deepConsultationPatterns)) {
      return {
        type: IntentType.DEEP_CONSULTATION,
        confidence: 0.85,
        maxResponseLength: 800,
        needsTools: true,
        suggestedTools: ['knowledge-search'],
        entities: this.extractEntities(text),
        isFollowUp,
      };
    }

    // 5. 检测简单查询
    if (this.matchPatterns(text, this.simpleQueryPatterns)) {
      return {
        type: IntentType.SIMPLE_QUERY,
        confidence: 0.8,
        maxResponseLength: 300,
        needsTools: false,
        entities: this.extractEntities(text),
        isFollowUp,
      };
    }

    // 6. 消息太短或不清楚，需要澄清
    if (text.length < 5 && !isFollowUp) {
      return {
        type: IntentType.CLARIFICATION,
        confidence: 0.7,
        maxResponseLength: 150,
        needsTools: false,
        isFollowUp,
      };
    }

    // 7. 默认：根据长度和内容判断
    const hasImmigrationKeywords = this.detectImmigrationCategory(text);
    if (hasImmigrationKeywords) {
      return {
        type: IntentType.DEEP_CONSULTATION,
        confidence: 0.7,
        maxResponseLength: 600,
        needsTools: true,
        suggestedTools: ['knowledge-search'],
        entities: this.extractEntities(text),
        isFollowUp,
      };
    }

    // 默认为简单查询
    return {
      type: IntentType.SIMPLE_QUERY,
      confidence: 0.6,
      maxResponseLength: 400,
      needsTools: false,
      entities: this.extractEntities(text),
      isFollowUp,
    };
  }

  /**
   * 检测是否为后续问题
   */
  private detectFollowUp(text: string, history: Message[]): boolean {
    if (history.length === 0) return false;

    // 代词检测
    const pronouns = ['这个', '那个', '它', '这', '那', '上面', '刚才', '前面'];
    if (pronouns.some(p => text.includes(p))) return true;

    // 省略主语的短问题
    if (text.length < 20 && !text.includes('我')) return true;

    // 以连接词开头
    const connectors = ['那', '然后', '接着', '还有', '另外', '所以'];
    if (connectors.some(c => text.startsWith(c))) return true;

    return false;
  }

  /**
   * 匹配模式
   */
  private matchPatterns(text: string, patterns: RegExp[]): boolean {
    return patterns.some(p => p.test(text));
  }

  /**
   * 检测需要的工具
   */
  private detectActionTools(text: string): string[] {
    const tools: string[] = [];
    for (const [tool, keywords] of Object.entries(this.toolKeywords)) {
      if (keywords.some(kw => text.includes(kw))) {
        tools.push(tool);
      }
    }
    return tools;
  }

  /**
   * 检测移民类别
   */
  private detectImmigrationCategory(text: string): string | null {
    for (const [category, keywords] of Object.entries(this.immigrationCategories)) {
      if (keywords.some(kw => text.includes(kw))) {
        return category;
      }
    }
    return null;
  }

  /**
   * 提取实体
   */
  private extractEntities(text: string): Record<string, string> {
    const entities: Record<string, string> = {};

    // 签证子类
    const visaMatch = text.match(/\b(189|190|491|482|494|186|188|132|820|801|143|500|485|600)\b/);
    if (visaMatch) {
      entities.visaSubclass = visaMatch[1];
    }

    // 移民类别
    const category = this.detectImmigrationCategory(text);
    if (category) {
      entities.category = category;
    }

    // 职业
    const occupationMatch = text.match(/(会计|工程师|IT|程序员|护士|厨师|电工|木工|焊工)/);
    if (occupationMatch) {
      entities.occupation = occupationMatch[1];
    }

    return entities;
  }
}

// 单例导出
export const intentClassifier = new IntentClassifier();