/**
 * 系统状态监控 API
 * 
 * GET: 获取系统整体状态和统计数据
 * 
 * 参考：flnxi_sucai/app/api/admin/system-status/route.ts
 */

import { NextRequest, NextResponse } from 'next/server'
import { getServerSession } from 'next-auth'
import { authOptions } from '@/lib/auth'
import { prisma } from '@/lib/prisma'

export async function GET(req: NextRequest) {
  try {
    const session = await getServerSession(authOptions)

    // 检查管理员权限
    if (!session || (session.user as any).role !== 'ADMIN') {
      return NextResponse.json(
        { error: '无权限访问系统状态' },
        { status: 403 }
      )
    }

    // 计算时间范围（30天前和7天前）
    const thirtyDaysAgo = new Date(Date.now() - 30 * 24 * 60 * 60 * 1000)
    const sevenDaysAgo = new Date(Date.now() - 7 * 24 * 60 * 60 * 1000)

    // 并行查询基础数据
    let newUsersThisMonth: any, newMaterialsThisMonth: any, siteSettings: any, recentMaterials: any, totalUsers: number, totalMaterials: number, activeUsers: number, departmentStats: any[], roleStats: any[]
    
    try {
      [newUsersThisMonth, newMaterialsThisMonth, siteSettings, recentMaterials, totalUsers, totalMaterials, activeUsers, departmentStats, roleStats] = await Promise.all([
        prisma.user.aggregate({
          _count: { id: true },
          where: { createdAt: { gte: thirtyDaysAgo } },
        }),
        prisma.material.aggregate({
          _count: { id: true },
          where: { createdAt: { gte: thirtyDaysAgo }, deletedAt: null } as any,
        }),
        prisma.systemSettings.findFirst({
          select: { siteName: true },
        }),
        prisma.material.findMany({
          take: 10,
          orderBy: { createdAt: 'desc' },
          where: { deletedAt: null } as any,
          select: {
            id: true,
            productModel: true,
            createdAt: true,
            user: {
              select: {
                username: true,
                email: true,
              },
            },
          },
        }),
        prisma.user.count(),
        prisma.material.count({ where: { deletedAt: null } as any }),
        prisma.user.count({ where: { updatedAt: { gte: sevenDaysAgo } } }),
        prisma.user.groupBy({
          by: ['department'],
          _count: { id: true },
        }),
        prisma.user.groupBy({
          by: ['role'],
          _count: { id: true },
        }),
      ])
    } catch (error: any) {
      console.error('[SystemStatus] Database query error:', error)
      // 降级处理
      newUsersThisMonth = { _count: { id: 0 } }
      newMaterialsThisMonth = { _count: { id: 0 } }
      siteSettings = null
      recentMaterials = []
      totalUsers = 0
      totalMaterials = 0
      activeUsers = 0
      departmentStats = []
      roleStats = []
    }

    // 获取素材统计（兼容旧数据库）
    let materialStats: any = {}
    try {
      // 尝试按素材类型分组统计
      const materialTypeStats = await prisma.material.groupBy({
        by: ['materialType'],
        _count: {
          id: true,
        },
        where: {
          deletedAt: null, // 只统计未删除的素材
        } as any,
      })

      const totalMaterials = materialTypeStats.reduce((sum, stat) => sum + stat._count.id, 0)

      materialStats = {
        total: totalMaterials,
        byType: materialTypeStats.reduce((acc, stat) => {
          acc[stat.materialType] = stat._count.id
          return acc
        }, {} as Record<string, number>),
      }

      // 获取已删除素材数量
      try {
        const deletedCount = await prisma.material.count({
          where: {
            deletedAt: { not: null },
          } as any,
        })
        materialStats.deleted = deletedCount
      } catch {
        // deletedAt 字段不存在，跳过
        materialStats.deleted = 0
      }
    } catch (error: any) {
      // 如果 deletedAt 字段不存在，降级统计
      if (error?.meta?.column?.includes('deletedAt')) {
        const materialTypeStats = await prisma.material.groupBy({
          by: ['materialType'],
          _count: {
            id: true,
          },
        })

        const totalMaterials = materialTypeStats.reduce((sum, stat) => sum + stat._count.id, 0)

        materialStats = {
          total: totalMaterials,
          byType: materialTypeStats.reduce((acc, stat) => {
            acc[stat.materialType] = stat._count.id
            return acc
          }, {} as Record<string, number>),
          deleted: 0, // 旧数据库没有软删除
        }
      } else {
        throw error
      }
    }

    // 获取下载统计（最近7天）
    let downloadStats: any = {}
    try {
      const recentDownloads = await (prisma as any).materialDownloadLog.count({
        where: {
          downloadedAt: {
            gte: sevenDaysAgo,
          },
        },
      })

      const totalDownloads = await (prisma as any).materialDownloadLog.count()

      downloadStats = {
        total: totalDownloads,
        recent7Days: recentDownloads,
      }
    } catch (error: any) {
      // 如果下载日志表不存在
      if (error?.meta?.table?.includes('material_download_logs')) {
        downloadStats = {
          total: 0,
          recent7Days: 0,
        }
      } else {
        throw error
      }
    }

    // 获取收藏统计
    let favoriteStats: any = {}
    try {
      const totalFavorites = await (prisma as any).materialFavorite.count()
      favoriteStats = {
        total: totalFavorites,
      }
    } catch (error: any) {
      // 如果收藏表不存在
      if (error?.meta?.table?.includes('material_favorites')) {
        favoriteStats = {
          total: 0,
        }
      } else {
        throw error
      }
    }

    // 获取存储统计（素材文件大小）
    const storageStats = await prisma.material.aggregate({
      _sum: {
        zipFileSize: true,
      },
    })

    const totalStorageBytes = Number(storageStats._sum.zipFileSize || 0)
    const totalStorageGB = (totalStorageBytes / (1024 * 1024 * 1024)).toFixed(2)

    // 从roleStats计算管理员和普通用户数量
    const adminUsers = roleStats.find((r: any) => r.role === 'ADMIN')?._count?.id || 0
    const regularUsers = roleStats.find((r: any) => r.role === 'USER')?._count?.id || 0

    // 系统信息
    const systemInfo = {
      nodeVersion: process.version,
      platform: process.platform,
      uptime: process.uptime(),
      memoryUsage: process.memoryUsage(),
      timestamp: new Date().toISOString(),
    }

    return NextResponse.json({
      users: {
        total: totalUsers,
        admin: adminUsers,
        regular: regularUsers,
      },
      materials: materialStats,
      downloads: downloadStats,
      favorites: favoriteStats,
      storage: {
        totalBytes: totalStorageBytes,
        totalGB: parseFloat(totalStorageGB),
      },
      system: systemInfo,
    })
  } catch (error) {
    console.error('[Admin] System status error:', error)
    return NextResponse.json(
      { error: '获取系统状态失败' },
      { status: 500 }
    )
  }
}