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

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

    const db = getDb()

    const total = (db.prepare('SELECT COUNT(*) as c FROM tickets').get() as any).c
    const open = (db.prepare("SELECT COUNT(*) as c FROM tickets WHERE current_status = 'open'").get() as any).c
    const inProgress = (db.prepare("SELECT COUNT(*) as c FROM tickets WHERE current_status = 'in_progress'").get() as any).c
    const resolved = (db.prepare("SELECT COUNT(*) as c FROM tickets WHERE current_status = 'resolved'").get() as any).c
    const closed = (db.prepare("SELECT COUNT(*) as c FROM tickets WHERE current_status = 'closed'").get() as any).c

    const thisMonth = new Date().toISOString().slice(0, 7)
    const monthTotal = (db.prepare("SELECT COUNT(*) as c FROM tickets WHERE assign_time LIKE ?").get(`${thisMonth}%`) as any).c

    const avgDuration = db.prepare("SELECT AVG(duration_minutes) as avg FROM tickets WHERE duration_minutes IS NOT NULL AND duration_minutes != ''").get() as any
    const avgAvailability = db.prepare("SELECT AVG(availability) as avg FROM tickets WHERE availability IS NOT NULL AND availability != ''").get() as any
    const avgDurationVal = Number(avgDuration?.avg)
    const avgAvailabilityVal = Number(avgAvailability?.avg)
    const slaRate = isNaN(avgAvailabilityVal) ? 0 : Math.round(avgAvailabilityVal * 10000) / 100

    // Category breakdown
    const categories = db.prepare(
      "SELECT fault_category, COUNT(*) as count FROM tickets WHERE fault_category IS NOT NULL AND fault_category != '' GROUP BY fault_category ORDER BY count DESC"
    ).all()

    // Recent 12 months trend
    const monthlyTrend = db.prepare(`
      SELECT strftime('%Y-%m', assign_time) as month, COUNT(*) as tickets,
        AVG(duration_minutes) as avg_duration
      FROM tickets WHERE assign_time IS NOT NULL
      GROUP BY strftime('%Y-%m', assign_time)
      ORDER BY month DESC LIMIT 13
    `).all()

    return NextResponse.json({
      overview: {
        total,
        open,
        in_progress: inProgress,
        resolved,
        closed,
        thisMonth: monthTotal,
        avgDuration: isNaN(avgDurationVal) ? 0 : Math.round(avgDurationVal),
        slaRate,
      },
      categories,
      monthlyTrend: (monthlyTrend as any[]).reverse(),
    })
  } catch (e) {
    const msg = e instanceof Error ? e.message : '查询失败'
    return NextResponse.json({ error: msg }, { status: 500 })
  }
}