import { NextRequest, NextResponse } from 'next/server'
import { getServerSession } from 'next-auth'
import { authOptions } from '@/lib/auth'
import { prisma } from '@/lib/prisma'
import {
  buildMaterialWhereFromSearchParams,
  MaterialQueryError,
} from '@/lib/material-query'

export async function GET(request: NextRequest) {
  const session = await getServerSession(authOptions)
  if (!session?.user || !(session.user as any).id) {
    return NextResponse.json({ error: '未登录', code: 'UNAUTHORIZED' }, { status: 401 })
  }

  const searchParams = request.nextUrl.searchParams
  const q = searchParams.get('q')

  if (!q || q.trim().length < 1) {
    return NextResponse.json({ suggestions: [] })
  }

  const keyword = q.trim()

  try {
    const { where: visibleWhere, empty } = await buildMaterialWhereFromSearchParams(
      new URLSearchParams(),
      session.user as any,
    )

    if (empty) {
      return NextResponse.json({ suggestions: [] })
    }

    const withVisibleWhere = (fieldWhere: any) => ({
      AND: [
        visibleWhere,
        fieldWhere,
      ],
    })

    // 并行查询三个字段的前缀匹配和模糊匹配
    // 为了性能，我们只取 DISTINCT 的值，并限制数量
    
    // 使用 Promise.all 并行查询
    const [spuResults, authorResults, sceneResults] = await Promise.all([
      // SPU 型号建议
      prisma.material.findMany({
        where: withVisibleWhere({
          productModel: { contains: keyword, mode: 'insensitive' },
        }),
        select: { productModel: true },
        distinct: ['productModel'],
        take: 5
      }),
      // 作者建议
      prisma.material.findMany({
        where: withVisibleWhere({
          authorName: { contains: keyword, mode: 'insensitive' },
        }),
        select: { authorName: true },
        distinct: ['authorName'],
        take: 3
      }),
      // 场景建议
      prisma.material.findMany({
        where: withVisibleWhere({
          sceneName: { contains: keyword, mode: 'insensitive' },
        }),
        select: { sceneName: true },
        distinct: ['sceneName'],
        take: 3
      })
    ])

    // 合并结果并去重
    const suggestionsSet = new Set<string>()
    const suggestions: Array<{ type: 'spu' | 'author' | 'scene', value: string }> = []

    const addSuggestion = (type: 'spu' | 'author' | 'scene', value: string) => {
      if (value && !suggestionsSet.has(value) && value.toLowerCase().includes(keyword.toLowerCase())) {
        suggestionsSet.add(value)
        suggestions.push({ type, value })
      }
    }

    spuResults.forEach(i => addSuggestion('spu', i.productModel))
    authorResults.forEach(i => addSuggestion('author', i.authorName))
    sceneResults.forEach(i => addSuggestion('scene', i.sceneName))

    return NextResponse.json({ suggestions: suggestions.slice(0, 10) })
  } catch (error) {
    if (error instanceof MaterialQueryError) {
      return NextResponse.json(
        { error: error.message, code: error.code },
        { status: error.status },
      )
    }

    console.error('Search suggestions error:', error)
    return NextResponse.json({ suggestions: [] }, { status: 500 })
  }
}