import type { NextRequest } from 'next/server'
import { NextResponse } from 'next/server'
import { getServerSession } from 'next-auth'
import { authOptions } from '@/lib/auth'
import { isDepartmentAdmin, isSystemAdmin } from '@/lib/department-permission'
import { getMaterialUploadStats } from '@/lib/admin-material-stats'

interface StatsSessionUser {
  role?: string | null
  managedDepartment?: string | null
  department?: string | null
}

export async function GET(request: NextRequest) {
  try {
    const session = await getServerSession(authOptions)
    const sessionUser = session?.user as StatsSessionUser | undefined

    const role = sessionUser?.role
    const canViewAllDepartments = isSystemAdmin(role)
    const canViewDepartmentScope = isDepartmentAdmin(role)
    const canViewStats = canViewAllDepartments || canViewDepartmentScope
    const scopeDepartmentName = canViewDepartmentScope
      ? String(sessionUser?.managedDepartment || sessionUser?.department || '').trim()
      : null

    if (!session?.user || !canViewStats) {
      return NextResponse.json({ error: '无权限' }, { status: 403 })
    }

    if (canViewDepartmentScope && !scopeDepartmentName) {
      return NextResponse.json({ error: '当前账号未绑定部门，无法查看统计数据' }, { status: 400 })
    }

    const { searchParams } = new URL(request.url)
    const startDate = searchParams.get('startDate')
    const endDate = searchParams.get('endDate')
    const departmentKey = searchParams.get('departmentKey')

    const stats = await getMaterialUploadStats({
      startDate,
      endDate,
      departmentKey,
      scopeDepartmentName,
    })

    return NextResponse.json({
      success: true,
      data: stats,
      meta: {
        canViewAllDepartments,
        scopeDepartmentName,
      },
    })
  } catch (error) {
    console.error('[Admin Data Stats] GET error:', error)
    return NextResponse.json({ error: '获取数据统计失败' }, { status: 500 })
  }
}