import { promises as fs } from 'fs'
import path from 'path'
import JSZip from 'jszip'
import { NextRequest, NextResponse } from 'next/server'
import { getServerSession } from 'next-auth'
import { authOptions } from '@/lib/auth'
import { prisma } from '@/lib/prisma'
import { ensureMaterialDownloadLogsTable } from '@/lib/material-download-log'
import {
  getWhiteBackgroundAssetWhereForSku,
  groupWhiteBackgroundAssetsBySku,
  hasAnyWhiteBackgroundAssetGroup,
  STANDARD_MODEL_WHITE_BG_VIEWS,
  type GroupedWhiteBackgroundAssets,
} from '@/lib/standard-model-white-background'

type DownloadType = 'model' | 'white-background'

type WhiteBackgroundAssetRecord = {
  assetType: string
  fileUrl: string
  fileName: string | null
  sortOrder: number
}

function resolveModelDownloadFileName(
  skuName: string,
  rawFileName?: string | null,
  rawFilePath?: string | null,
): string {
  const ext = path.extname(rawFileName || rawFilePath || '') || '.zip'
  return `${skuName}${ext}`
}

function resolveLocalFilePath(fileUrl: string): string {
  if (path.isAbsolute(fileUrl)) {
    return fileUrl
  }
  return path.join(process.cwd(), fileUrl)
}

function getWhiteBackgroundZipEntries(group: GroupedWhiteBackgroundAssets<WhiteBackgroundAssetRecord>) {
  const fixedEntries = STANDARD_MODEL_WHITE_BG_VIEWS
    .map((view) => {
      const asset = group.fixed[view.key]
      if (!asset) {
        return null
      }
      return {
        fileName: asset.fileName || `${view.label}${path.extname(asset.fileUrl) || '.jpg'}`,
        fileUrl: asset.fileUrl,
      }
    })
    .filter((entry): entry is { fileName: string; fileUrl: string } => Boolean(entry))

  const otherEntries = group.other.map((asset) => ({
    fileName: asset.fileName || path.basename(asset.fileUrl),
    fileUrl: asset.fileUrl,
    directory: 'other',
  }))

  return {
    fixedEntries,
    otherEntries,
  }
}

export async function POST(
  request: NextRequest,
  { params }: { params: { id: string } }
) {
  try {
    const session = await getServerSession(authOptions)
    if (!session?.user || !(session.user as any).id) {
      return NextResponse.json({ error: '请先登录' }, { status: 401 })
    }

    const userId = (session.user as any).id
    const user = await prisma.user.findUnique({
      where: { id: userId },
      select: { canDownload: true },
    })

    if (!user?.canDownload) {
      return NextResponse.json({ error: '您没有下载权限，请联系管理员' }, { status: 403 })
    }

    const materialId = params.id
    const body = await request.json()
    const skuIds = Array.isArray(body?.skuIds) ? body.skuIds : []
    const downloadType: DownloadType = body?.downloadType === 'white-background' ? 'white-background' : 'model'

    if (skuIds.length === 0) {
      return NextResponse.json({ error: '请选择要下载的 SKU' }, { status: 400 })
    }

    const material = await prisma.material.findFirst({
      where: { id: materialId, deletedAt: null },
      select: { id: true, productModel: true, materialType: true },
    })

    if (!material) {
      return NextResponse.json({ error: '素材不存在或已被删除' }, { status: 404 })
    }

    if (material.materialType !== '标准模型') {
      return NextResponse.json({ error: '只有标准模型类型才支持 SKU 批量下载' }, { status: 400 })
    }

    const skus = await prisma.materialSku.findMany({
      where: {
        id: { in: skuIds },
        materialId,
        deletedAt: null,
      },
      select: {
        id: true,
        skuName: true,
        filePath: true,
        fileName: true,
      },
      orderBy: { sortOrder: 'asc' },
    })

    if (skus.length === 0) {
      return NextResponse.json({ error: '没有找到可下载的 SKU' }, { status: 404 })
    }

    const zip = new JSZip()
    let addedCount = 0

    if (downloadType === 'white-background') {
      const whiteBackgroundAssets = await prisma.materialAsset.findMany({
        where: {
          materialId,
          OR: skuIds.flatMap((skuId: string) => getWhiteBackgroundAssetWhereForSku(skuId).OR),
        },
        select: {
          assetType: true,
          fileUrl: true,
          fileName: true,
          sortOrder: true,
        },
      })

      const whiteBackgroundMap = groupWhiteBackgroundAssetsBySku<WhiteBackgroundAssetRecord>(
        whiteBackgroundAssets,
      )

      for (const sku of skus) {
        const whiteBackgroundGroup = whiteBackgroundMap.get(sku.id)
        if (!whiteBackgroundGroup || !hasAnyWhiteBackgroundAssetGroup(whiteBackgroundGroup)) {
          continue
        }

        const { fixedEntries, otherEntries } = getWhiteBackgroundZipEntries(whiteBackgroundGroup)
        if (fixedEntries.length === 0 && otherEntries.length === 0) {
          continue
        }

        try {
          for (const entry of fixedEntries) {
            const fileBuffer = await fs.readFile(resolveLocalFilePath(entry.fileUrl))
            zip.file(`${sku.skuName}/${entry.fileName}`, fileBuffer)
          }

          for (const entry of otherEntries) {
            const fileBuffer = await fs.readFile(resolveLocalFilePath(entry.fileUrl))
            zip.file(`${sku.skuName}/other/${entry.fileName}`, fileBuffer)
          }

          addedCount++
        } catch (error) {
          console.error(`[SKU Batch Download] 添加白底图失败: ${sku.id}`, error)
        }
      }
    } else {
      for (const sku of skus) {
        try {
          if (!sku.filePath) {
            continue
          }

          const filePath = path.join(process.cwd(), 'uploads', sku.filePath)
          const fileName = resolveModelDownloadFileName(
            sku.skuName,
            sku.fileName || null,
            sku.filePath || null,
          )

          const fileBuffer = await fs.readFile(filePath)
          zip.file(fileName, fileBuffer)
          addedCount++
        } catch (error) {
          console.error(`[SKU Batch Download] 添加模型失败: ${sku.id}`, error)
        }
      }
    }

    if (addedCount === 0) {
      return NextResponse.json(
        { error: downloadType === 'white-background' ? '没有可下载的白底图文件' : '没有可下载的模型文件' },
        { status: 404 }
      )
    }

    const zipBuffer = await zip.generateAsync({
      type: 'nodebuffer',
      compression: 'DEFLATE',
      compressionOptions: { level: 6 },
    })

    const filename = `${material.productModel}_${downloadType === 'white-background' ? 'SKU白底图' : 'SKU模型'}_${Date.now()}.zip`

    recordBatchDownloadLog(materialId, userId).catch((error) => {
      console.error('[SKU Batch Download] 记录下载日志失败:', error)
    })

    return new NextResponse(zipBuffer as any, {
      headers: {
        'Content-Type': 'application/zip',
        'Content-Length': zipBuffer.length.toString(),
        'Content-Disposition': `attachment; filename="${encodeURIComponent(filename)}"`,
      },
    })
  } catch (error) {
    console.error('[SKU Batch Download] 下载失败:', error)
    return NextResponse.json(
      { error: '下载失败: ' + (error instanceof Error ? error.message : '未知错误') },
      { status: 500 }
    )
  }
}

async function recordBatchDownloadLog(materialId: string, userId: string) {
  await ensureMaterialDownloadLogsTable()
  await Promise.all([
    prisma.materialDownloadLog.create({
      data: {
        materialId,
        userId,
        downloadedAt: new Date(),
      },
    }),
    prisma.material.update({
      where: { id: materialId },
      data: {
        downloadCount: {
          increment: 1,
        },
      },
    }),
  ])
}