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

// Get all users (admin only) - 支持分页
export async function GET(request: NextRequest) {
  try {
    const session = await getServerSession(authOptions)

    if (!session || (session.user as any).role !== 'ADMIN') {
      return NextResponse.json(
        { error: '无权限' },
        { status: 403 }
      )
    }

    const { searchParams } = new URL(request.url)
    const page = parseInt(searchParams.get('page') || '1', 10)
    const pageSize = Math.min(parseInt(searchParams.get('pageSize') || '20', 10), 100) // 最大100条
    const skip = (page - 1) * pageSize
    const keyword = searchParams.get('search')?.trim() || ''

    // 并行查询总数和数据
    const where =
      keyword
        ? {
            OR: [
              { username: { contains: keyword, mode: 'insensitive' as const } },
              { email: { contains: keyword, mode: 'insensitive' as const } },
              { department: { contains: keyword, mode: 'insensitive' as const } },
            ],
          }
        : {}

    const [total, users] = await Promise.all([
      prisma.user.count({ where }),
      prisma.user.findMany({
        where,
        select: {
          id: true,
          email: true,
          username: true,
          parentId: true,
          role: true,
          isActive: true,
          canDownload: true,
          department: true,
          managedDepartment: true,
          isSuperAdmin: true,
          createdAt: true,
          _count: {
            select: {
              materials: true,
            },
          },
        },
        orderBy: {
          createdAt: 'asc', // 按创建时间升序，第一个用户就是最高权限账号
        },
        skip,
        take: pageSize,
      })
    ])

    return NextResponse.json({
      users,
      pagination: {
        page,
        pageSize,
        total,
        totalPages: Math.ceil(total / pageSize)
      }
    })
  } catch (error) {
    console.error('[AdminUsers] Get error:', error)
    return NextResponse.json(
      { error: '获取用户列表失败' },
      { status: 500 }
    )
  }
}

// Delete user (admin only)
export async function DELETE(req: NextRequest) {
  try {
    const session = await getServerSession(authOptions)

    if (!session || (session.user as any).role !== 'ADMIN') {
      return NextResponse.json(
        { error: '无权限' },
        { status: 403 }
      )
    }

    const { searchParams } = new URL(req.url)
    const id = searchParams.get('id')

    if (!id) {
      return NextResponse.json(
        { error: '缺少用户ID' },
        { status: 400 }
      )
    }

    // Don't allow deleting self
    if (id === (session.user as any).id) {
      return NextResponse.json(
        { error: '不能删除自己' },
        { status: 400 }
      )
    }

    await prisma.user.delete({
      where: { id },
    })

    return NextResponse.json({ message: '删除成功' })
  } catch (error) {
    console.error('Error deleting user:', error)
    return NextResponse.json(
      { error: '删除失败' },
      { status: 500 }
    )
  }
}