/**
 * 学习时长追踪服务
 * 自动记录用户在各页面的学习时长
 */

class LearningTimeTracker {
  constructor() {
    this.currentPage = null;
    this.startTime = null;
    this.sessionData = {};
  }

  /**
   * 开始追踪页面
   * @param {String} pageName - 页面名称
   */
  startTracking(pageName) {
    // 如果之前有页面在追踪，先结束它
    if (this.currentPage && this.startTime) {
      this.endTracking();
    }

    this.currentPage = pageName;
    this.startTime = Date.now();
    
    console.log(`[学习追踪] 开始: ${pageName}`);
  }

  /**
   * 结束追踪
   */
  endTracking() {
    if (!this.currentPage || !this.startTime) {
      return;
    }

    const endTime = Date.now();
    const duration = Math.floor((endTime - this.startTime) / 1000); // 秒
    
    // 只记录超过5秒的有效学习时长（过滤快速切换）
    if (duration >= 5) {
      this.recordDuration(this.currentPage, duration);
      console.log(`[学习追踪] 结束: ${this.currentPage}, 时长: ${duration}秒`);
    }

    this.currentPage = null;
    this.startTime = null;
  }

  /**
   * 记录学习时长
   * @param {String} pageName - 页面名称
   * @param {Number} duration - 时长（秒）
   */
  recordDuration(pageName, duration) {
    const today = this.getTodayString();
    const now = new Date();

    // 1. 更新总学习数据
    const learningData = wx.getStorageSync('learning_data') || {
      totalHours: 0,
      totalSeconds: 0,
      dailyRecords: []
    };

    learningData.totalSeconds = (learningData.totalSeconds || 0) + duration;
    learningData.totalHours = parseFloat((learningData.totalSeconds / 3600).toFixed(1));

    // 更新每日记录
    let todayRecord = learningData.dailyRecords.find(r => r.date === today);
    if (!todayRecord) {
      todayRecord = {
        date: today,
        seconds: 0,
        hours: 0,
        sessions: []
      };
      learningData.dailyRecords.push(todayRecord);
    }

    todayRecord.seconds += duration;
    todayRecord.hours = parseFloat((todayRecord.seconds / 3600).toFixed(2));
    todayRecord.sessions.push({
      page: pageName,
      duration: duration,
      timestamp: now.getTime()
    });

    // 只保留最近365天的记录
    if (learningData.dailyRecords.length > 365) {
      learningData.dailyRecords = learningData.dailyRecords
        .sort((a, b) => new Date(b.date) - new Date(a.date))
        .slice(0, 365);
    }

    wx.setStorageSync('learning_data', learningData);

    // 2. 更新每日活跃度（用于热力图）
    const dailyActivity = wx.getStorageSync('daily_activity') || {};
    dailyActivity[today] = (dailyActivity[today] || 0) + Math.floor(duration / 60); // 转为分钟
    wx.setStorageSync('daily_activity', dailyActivity);

    // 3. 更新模块使用时长
    const moduleMapping = {
      'courses': 'course',
      'course-detail': 'course',
      'forum': 'forum',
      'forum-detail': 'forum',
      'post': 'forum',
      'gpa': 'tools',
      'schedule': 'tools',
      'countdown': 'tools',
      'tools': 'tools',
      'ai-assistant': 'ai',
      'dashboard': 'tools'
    };

    const module = moduleMapping[pageName] || 'other';
    const moduleUsage = wx.getStorageSync('module_usage') || {
      course: 0,
      forum: 0,
      tools: 0,
      ai: 0
    };

    moduleUsage[module] = (moduleUsage[module] || 0) + parseFloat((duration / 3600).toFixed(2));
    wx.setStorageSync('module_usage', moduleUsage);

    // 4. 更新学习画像
    this.updateLearningProfile(pageName, duration);
  }

  /**
   * 更新学习画像
   */
  updateLearningProfile(pageName, duration) {
    const profile = wx.getStorageSync('learning_profile') || {
      focus: 0,        // 专注度
      activity: 0,     // 活跃度
      duration: 0,     // 学习时长
      breadth: 0,      // 知识广度
      interaction: 0,  // 互动性
      persistence: 0   // 坚持度
    };

    // 专注度：基于单次学习时长（超过30分钟+10，超过1小时+20）
    if (duration >= 3600) {
      profile.focus = Math.min(100, profile.focus + 2);
    } else if (duration >= 1800) {
      profile.focus = Math.min(100, profile.focus + 1);
    }

    // 活跃度：每次学习+1
    profile.activity = Math.min(100, profile.activity + 0.5);

    // 学习时长：每小时+5
    profile.duration = Math.min(100, profile.duration + (duration / 3600) * 5);

    // 知识广度：访问课程相关页面+1
    if (pageName.includes('course')) {
      profile.breadth = Math.min(100, profile.breadth + 0.3);
    }

    // 互动性：论坛相关+2
    if (pageName.includes('forum') || pageName.includes('post')) {
      profile.interaction = Math.min(100, profile.interaction + 1);
    }

    // 坚持度：每天学习+3
    const learningData = wx.getStorageSync('learning_data') || {};
    const continuousDays = this.calculateContinuousDays(learningData.dailyRecords || []);
    profile.persistence = Math.min(100, continuousDays * 3);

    wx.setStorageSync('learning_profile', profile);
  }

  /**
   * 计算连续学习天数
   */
  calculateContinuousDays(records) {
    if (!records || records.length === 0) return 0;

    const sortedRecords = records.sort((a, b) => new Date(b.date) - new Date(a.date));
    let continuousDays = 0;
    const today = new Date();
    today.setHours(0, 0, 0, 0);

    for (let i = 0; i < sortedRecords.length; i++) {
      const recordDate = new Date(sortedRecords[i].date);
      recordDate.setHours(0, 0, 0, 0);
      const daysDiff = Math.floor((today - recordDate) / (1000 * 60 * 60 * 24));

      if (daysDiff === i) {
        continuousDays++;
      } else {
        break;
      }
    }

    return continuousDays;
  }

  /**
   * 获取今天的日期字符串
   */
  getTodayString() {
    const now = new Date();
    const year = now.getFullYear();
    const month = String(now.getMonth() + 1).padStart(2, '0');
    const day = String(now.getDate()).padStart(2, '0');
    return `${year}-${month}-${day}`;
  }

  /**
   * 获取学习统计
   */
  getStats() {
    const learningData = wx.getStorageSync('learning_data') || {
      totalHours: 0,
      totalSeconds: 0,
      dailyRecords: []
    };

    const continuousDays = this.calculateContinuousDays(learningData.dailyRecords);

    return {
      totalHours: learningData.totalHours || 0,
      totalSeconds: learningData.totalSeconds || 0,
      continuousDays: continuousDays,
      todayHours: this.getTodayHours()
    };
  }

  /**
   * 获取今天的学习时长
   */
  getTodayHours() {
    const today = this.getTodayString();
    const learningData = wx.getStorageSync('learning_data') || { dailyRecords: [] };
    const todayRecord = learningData.dailyRecords.find(r => r.date === today);
    return todayRecord ? todayRecord.hours : 0;
  }
}

// 创建全局实例
const tracker = new LearningTimeTracker();

module.exports = {
  tracker,
  
  /**
   * 页面onShow时调用
   */
  onPageShow(pageName) {
    tracker.startTracking(pageName);
  },

  /**
   * 页面onHide时调用
   */
  onPageHide() {
    tracker.endTracking();
  },

  /**
   * 页面onUnload时调用
   */
  onPageUnload() {
    tracker.endTracking();
  },

  /**
   * 获取统计数据
   */
  getStats() {
    return tracker.getStats();
  }
};