import { NextRequest, NextResponse } from "next/server"
import { DatabaseService } from "@/lib/services/database-service"

const dbService = new DatabaseService()

export async function GET(request: NextRequest) {
  try {
    // 獲取總用戶數
    const totalUsersResult = await dbService.query(`
      SELECT COUNT(*) as total FROM users WHERE is_active = TRUE
    `)
    const totalUsers = totalUsersResult[0]?.total || 0

    // 獲取今日活躍用戶數（今日有登入記錄的用戶）
    const today = new Date().toISOString().split('T')[0]
    const todayActiveUsersResult = await dbService.query(`
      SELECT COUNT(DISTINCT user_id) as count 
      FROM activity_logs 
      WHERE DATE(created_at) = ? AND action = 'login'
    `, [today])
    const todayActiveUsers = todayActiveUsersResult[0]?.count || 0

    // 獲取昨日活躍用戶數（用於比較）
    const yesterday = new Date(Date.now() - 24 * 60 * 60 * 1000).toISOString().split('T')[0]
    const yesterdayActiveUsersResult = await dbService.query(`
      SELECT COUNT(DISTINCT user_id) as count 
      FROM activity_logs 
      WHERE DATE(created_at) = ? AND action = 'login'
    `, [yesterday])
    const yesterdayActiveUsers = yesterdayActiveUsersResult[0]?.count || 0

    // 計算今日活躍用戶增長率
    const todayActiveGrowth = yesterdayActiveUsers > 0 
      ? ((todayActiveUsers - yesterdayActiveUsers) / yesterdayActiveUsers * 100).toFixed(1)
      : 0

    // 獲取平均評分
    const avgRatingResult = await dbService.query(`
      SELECT AVG(rating) as avg_rating FROM apps WHERE is_active = TRUE AND rating > 0
    `)
    const avgRating = avgRatingResult[0]?.avg_rating || 0

    // 獲取上週平均評分（用於比較）
    const lastWeek = new Date(Date.now() - 7 * 24 * 60 * 60 * 1000).toISOString().split('T')[0]
    const lastWeekRatingResult = await dbService.query(`
      SELECT AVG(rating) as avg_rating 
      FROM apps 
      WHERE is_active = TRUE AND rating > 0 AND created_at < ?
    `, [lastWeek])
    const lastWeekRating = lastWeekRatingResult[0]?.avg_rating || 0

    // 計算評分增長
    const ratingGrowth = lastWeekRating > 0 
      ? (avgRating - lastWeekRating).toFixed(1)
      : 0

    // 獲取應用總數
    const totalAppsResult = await dbService.query(`
      SELECT COUNT(*) as total FROM apps WHERE is_active = TRUE
    `)
    const totalApps = totalAppsResult[0]?.total || 0

    // 獲取本週新增應用數
    const weekStart = new Date(Date.now() - 7 * 24 * 60 * 60 * 1000).toISOString().split('T')[0]
    const newThisWeekResult = await dbService.query(`
      SELECT COUNT(*) as count 
      FROM apps 
      WHERE is_active = TRUE AND DATE(created_at) >= ?
    `, [weekStart])
    const newThisWeek = newThisWeekResult[0]?.count || 0

    // 獲取上月用戶數（用於比較）
    const lastMonth = new Date(Date.now() - 30 * 24 * 60 * 60 * 1000).toISOString().split('T')[0]
    const lastMonthUsersResult = await dbService.query(`
      SELECT COUNT(*) as total 
      FROM users 
      WHERE is_active = TRUE AND created_at < ?
    `, [lastMonth])
    const lastMonthUsers = lastMonthUsersResult[0]?.total || 0

    // 計算用戶增長率
    const userGrowth = lastMonthUsers > 0 
      ? ((totalUsers - lastMonthUsers) / lastMonthUsers * 100).toFixed(1)
      : 0

    // 獲取近7天的使用趨勢數據
    const dailyUsageData = []
    for (let i = 6; i >= 0; i--) {
      const date = new Date(Date.now() - i * 24 * 60 * 60 * 1000)
      const dateStr = date.toISOString().split('T')[0]
      const dayName = ["日", "一", "二", "三", "四", "五", "六"][date.getDay()]
      
      // 獲取當日活躍用戶數
      const dailyUsersResult = await dbService.query(`
        SELECT COUNT(DISTINCT user_id) as count 
        FROM activity_logs 
        WHERE DATE(created_at) = ? AND action IN ('login', 'view')
      `, [dateStr])
      const dailyUsers = dailyUsersResult[0]?.count || 0

      // 獲取當日會話數
      const dailySessionsResult = await dbService.query(`
        SELECT COUNT(*) as count 
        FROM activity_logs 
        WHERE DATE(created_at) = ? AND action = 'view'
      `, [dateStr])
      const dailySessions = dailySessionsResult[0]?.count || 0

      dailyUsageData.push({
        date: `${date.getMonth() + 1}/${date.getDate()}`,
        fullDate: date.toLocaleDateString("zh-TW"),
        dayName: dayName,
        users: dailyUsers,
        sessions: dailySessions,
        cpuPeak: Math.min(80, 40 + dailyUsers * 0.1), // 模擬CPU使用率
        avgCpu: Math.min(70, 30 + dailyUsers * 0.08),
        memoryPeak: Math.min(75, 35 + dailyUsers * 0.12),
        requests: dailySessions * 5 // 模擬請求數
      })
    }

    // 獲取應用類別分布
    const categoryDataResult = await dbService.query(`
      SELECT 
        type as category,
        COUNT(*) as app_count,
        SUM(views_count) as total_views
      FROM apps 
      WHERE is_active = TRUE 
      GROUP BY type 
      ORDER BY app_count DESC
    `)
    
    const totalAppCount = categoryDataResult.reduce((sum, item) => sum + item.app_count, 0)
    const categoryData = categoryDataResult.map((item, index) => {
      const colors = ["#3b82f6", "#ef4444", "#10b981", "#f59e0b", "#8b5cf6"]
      return {
        name: item.category,
        value: Math.round((item.app_count / totalAppCount) * 100),
        color: colors[index % colors.length],
        users: Math.round(item.total_views * 0.3), // 估算用戶數
        apps: item.app_count
      }
    })

    // 獲取熱門應用排行
    const topAppsResult = await dbService.query(`
      SELECT 
        a.name,
        a.views_count as views,
        a.rating,
        a.type as category
      FROM apps a
      WHERE a.is_active = TRUE
      ORDER BY a.views_count DESC
      LIMIT 5
    `)
    
    const topApps = topAppsResult.map(app => ({
      name: app.name,
      views: app.views || 0,
      rating: parseFloat(app.rating) || 0,
      category: app.category
    }))

    // 獲取用戶滿意度數據
    const satisfactionResult = await dbService.query(`
      SELECT 
        AVG(rating) as avg_rating,
        COUNT(*) as total_ratings
      FROM user_ratings 
      WHERE created_at >= DATE_SUB(NOW(), INTERVAL 7 DAY)
    `)
    
    const satisfaction = satisfactionResult[0] || { avg_rating: 0, total_ratings: 0 }
    const satisfactionRate = satisfaction.avg_rating > 0 
      ? Math.round((satisfaction.avg_rating / 5) * 100)
      : 92 // 預設值

    return NextResponse.json({
      success: true,
      data: {
        // 關鍵指標
        totalUsers,
        todayActiveUsers,
        todayActiveGrowth: parseFloat(todayActiveGrowth),
        avgRating: parseFloat(avgRating.toFixed(1)),
        ratingGrowth: parseFloat(ratingGrowth),
        totalApps,
        newThisWeek,
        userGrowth: parseFloat(userGrowth),
        
        // 趨勢數據
        dailyUsageData,
        categoryData,
        topApps,
        
        // 滿意度數據
        satisfactionRate,
        weeklyFeedback: satisfaction.total_ratings || 0
      }
    })

  } catch (error) {
    console.error('獲取分析數據錯誤:', error)
    return NextResponse.json(
      { success: false, error: '獲取分析數據時發生錯誤' },
      { status: 500 }
    )
  }
}