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) {
  const session = await getServerSession(authOptions)
  if (!session) return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })

  const { searchParams } = new URL(req.url)
  const clientId = searchParams.get('clientId')
  const from = searchParams.get('from')
  const to = searchParams.get('to')
  const format = searchParams.get('format')

  const where: any = {}
  if (clientId) where.clientId = clientId
  if (from || to) {
    where.sentAt = {}
    if (from) where.sentAt.gte = new Date(from)
    if (to) where.sentAt.lte = new Date(to + 'T23:59:59Z')
  }

  const logs = await prisma.smsLog.findMany({
    where,
    include: { client: { select: { name: true } }, queue: true },
    orderBy: { sentAt: 'desc' },
    take: format === 'csv' ? 10000 : 500,
  })

  if (format === 'csv') {
    const headers = ['Date', 'Client', 'Student Name', 'Student ID', 'Phone', 'Event', 'Status', 'Error']
    const rows = logs.map(l => [
      new Date(l.sentAt).toISOString(),
      l.client.name,
      l.queue.studentName,
      l.queue.studentId,
      l.phone,
      l.queue.event,
      l.status,
      l.errorReason || '',
    ])
    const csv = [headers, ...rows].map(r => r.map(v => `"${String(v).replace(/"/g, '""')}"`).join(',')).join('\n')
    return new NextResponse(csv, {
      headers: {
        'Content-Type': 'text/csv',
        'Content-Disposition': `attachment; filename="sms-report-${Date.now()}.csv"`,
      },
    })
  }

  // Stats summary
  const stats = {
    total: logs.length,
    success: logs.filter(l => l.status === 'SUCCESS').length,
    failed: logs.filter(l => l.status === 'FAILED').length,
    logs,
  }

  return NextResponse.json(stats)
}