import { NextRequest, NextResponse } from 'next/server'
import { getDb } from '@/lib/db'
import { initDatabase } from '@/lib/db-schema'
import { getCurrentUser } from '@/lib/auth'

export async function GET(request: NextRequest) {
  try {
    initDatabase()
    const user = await getCurrentUser()
    if (!user) return NextResponse.json({ error: '未登录' }, { status: 401 })

    const { searchParams } = request.nextUrl
    const period = searchParams.get('period') || 'all' // 'all' | 'month' | 'quarter'

    const db = getDb()
    let dateCondition = ''
    const now = new Date()

    if (period === 'month') {
      dateCondition = `AND assign_time >= '${now.getFullYear()}-${String(now.getMonth() + 1).padStart(2, '0')}-01'`
    } else if (period === 'quarter') {
      const qStart = new Date(now.getFullYear(), Math.floor(now.getMonth() / 3) * 3, 1)
      dateCondition = `AND assign_time >= '${qStart.getFullYear()}-${String(qStart.getMonth() + 1).padStart(2, '0')}-01'`
    }

    // Overall SLA rate
    const slaData = db.prepare(`
      SELECT
        COUNT(*) as total_closed,
        SUM(CASE WHEN counted_in_sla = 1 THEN 1 ELSE 0 END) as sla_pass
      FROM tickets
      WHERE current_status IN ('resolved', 'closed') ${dateCondition}
    `).get() as any

    // SLA by category
    const byCategory = db.prepare(`
      SELECT
        fault_category,
        COUNT(*) as total,
        SUM(CASE WHEN counted_in_sla = 1 THEN 1 ELSE 0 END) as sla_pass
      FROM tickets
      WHERE current_status IN ('resolved', 'closed') AND fault_category IS NOT NULL ${dateCondition}
      GROUP BY fault_category
      ORDER BY total DESC
    `).all()

    // SLA by month
    const byMonth = db.prepare(`
      SELECT
        strftime('%Y-%m', close_time) as month,
        COUNT(*) as total,
        SUM(CASE WHEN counted_in_sla = 1 THEN 1 ELSE 0 END) as sla_pass
      FROM tickets
      WHERE current_status IN ('resolved', 'closed') AND close_time IS NOT NULL ${dateCondition}
      GROUP BY strftime('%Y-%m', close_time)
      ORDER BY month DESC
      LIMIT 12
    `).all()

    return NextResponse.json({
      overall: {
        total: slaData.total_closed,
        pass: slaData.sla_pass,
        rate: slaData.total_closed > 0 ? Math.round((slaData.sla_pass / slaData.total_closed) * 100) : 0,
      },
      byCategory,
      byMonth: (byMonth as any[]).reverse(),
    })
  } catch (e) {
    const msg = e instanceof Error ? e.message : '查询失败'
    return NextResponse.json({ error: msg }, { status: 500 })
  }
}