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

// GET - 获取邀请链接列表（仅管理员）
export async function GET(req: NextRequest) {
  try {
    const session = await getServerSession(authOptions)

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

    // 支持分页
    const { searchParams } = new URL(req.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

    // 并行查询总数和数据
    const [total, invitations] = await Promise.all([
      prisma.invitation.count(),
      prisma.invitation.findMany({
        orderBy: { createdAt: 'desc' },
        skip,
        take: pageSize,
        select: {
          id: true,
          code: true,
          createdBy: true,
          maxUses: true,
          currentUses: true,
          expiresAt: true,
          isActive: true,
          createdAt: true,
          // 不返回敏感信息
        }
      })
    ])

    // 生成完整邀请链接（统一使用集中配置策略）
    const baseUrl = resolveBaseUrl(req)
    const invitationsWithUrl = invitations.map(invitation => ({
      ...invitation,
      inviteUrl: `${baseUrl}/register?invite=${invitation.code}`,
    }))

    return NextResponse.json({
      invitations: invitationsWithUrl,
      pagination: {
        page,
        pageSize,
        total,
        totalPages: Math.ceil(total / pageSize)
      }
    })
  } catch (error) {
    console.error('[Invitations] GET error:', error)
    return NextResponse.json(
      { error: '获取邀请链接失败' },
      { status: 500 }
    )
  }
}

// POST - 创建邀请链接（仅管理员）
export async function POST(req: NextRequest) {
  try {
    const session = await getServerSession(authOptions)

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

    const { maxUses, expiresInDays } = await req.json()
    const userId = (session.user as any).id

    // 生成唯一邀请码（8位随机字符串）
    const code = randomBytes(4).toString('hex').toUpperCase()

    // 计算过期时间
    const expiresAt = expiresInDays 
      ? new Date(Date.now() + expiresInDays * 24 * 60 * 60 * 1000)
      : null

    const invitation = await prisma.invitation.create({
      data: {
        code,
        createdBy: userId,
        maxUses: maxUses || 1,
        expiresAt,
      },
    })

    // 生成完整邀请链接（统一使用集中配置策略）
    const baseUrl = resolveBaseUrl(req)
    const inviteUrl = `${baseUrl}/register?invite=${code}`

    return NextResponse.json({
      ...invitation,
      inviteUrl,
    })
  } catch (error) {
    console.error('[Invitations] POST error:', error)
    return NextResponse.json(
      { error: '创建邀请链接失败' },
      { status: 500 }
    )
  }
}