import { NextResponse } from 'next/server'
import { prisma } from '@/lib/prisma'

// Get material statistics (total count and monthly breakdown)
// 优化：使用SQL聚合查询，避免加载所有数据到内存
export async function GET() {
  try {
    // 并行查询总数和按月统计
    const [total, monthlyStats] = await Promise.all([
      prisma.material.count(),
      prisma.$queryRaw<Array<{
        year: number
        month: number
        count: bigint
      }>>`
        SELECT 
          EXTRACT(YEAR FROM created_at)::int as year,
          EXTRACT(MONTH FROM created_at)::int as month,
          COUNT(*)::bigint as count
        FROM materials
        GROUP BY EXTRACT(YEAR FROM created_at), EXTRACT(MONTH FROM created_at)
        ORDER BY year DESC, month DESC
      `
    ])

    // 格式化月份数据
    const months = monthlyStats.map(item => {
      const monthKey = `${item.year}-${String(item.month).padStart(2, '0')}`
      return {
        value: monthKey,
        label: `${item.year}年${item.month}月`,
        count: Number(item.count)
      }
    })

    return NextResponse.json({
      total,
      months
    })
  } catch (error) {
    console.error('[MaterialStats] Get error:', error)
    return NextResponse.json(
      { error: '获取统计数据失败' },
      { status: 500 }
    )
  }
}