/**
 * 模板素材迁移 API
 * 
 * POST: 将使用指定模板的素材迁移到另一个模板
 */

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

async function ensureAdmin() {
  const session = await getServerSession(authOptions)
  if (!session || (session.user as any)?.role !== 'ADMIN') {
    return null
  }
  return session
}

/**
 * POST /api/admin/upload-templates/[id]/migrate
 * 
 * 将使用源模板的素材迁移到目标模板
 * 
 * Body:
 * - targetTemplateId: 目标模板ID
 * - updateMaterialType: 是否同时更新素材的 materialType 字段（可选，默认 true）
 */
export async function POST(
  req: NextRequest,
  { params }: { params: { id: string } }
) {
  try {
    const session = await ensureAdmin()
    if (!session) {
      return NextResponse.json({ error: '无权限' }, { status: 403 })
    }

    const sourceTemplateId = params.id
    const body = await req.json()
    const { targetTemplateId, updateMaterialType = true } = body

    if (!targetTemplateId) {
      return NextResponse.json({ 
        error: '请选择目标模板',
        errorCode: 'MISSING_TARGET',
      }, { status: 400 })
    }

    if (sourceTemplateId === targetTemplateId) {
      return NextResponse.json({ 
        error: '源模板和目标模板不能相同',
        errorCode: 'SAME_TEMPLATE',
      }, { status: 400 })
    }

    // 检查源模板是否存在
    const sourceTemplate = await prisma.uploadTemplate.findUnique({
      where: { id: sourceTemplateId },
      select: { 
        id: true, 
        name: true,
        materialType: true,
        _count: { select: { materials: true } }
      },
    })

    if (!sourceTemplate) {
      return NextResponse.json({ 
        error: '源模板不存在',
        errorCode: 'SOURCE_NOT_FOUND',
      }, { status: 404 })
    }

    // 检查目标模板是否存在
    const targetTemplate = await prisma.uploadTemplate.findUnique({
      where: { id: targetTemplateId },
      select: { 
        id: true, 
        name: true,
        materialType: true,
      },
    })

    if (!targetTemplate) {
      return NextResponse.json({ 
        error: '目标模板不存在',
        errorCode: 'TARGET_NOT_FOUND',
      }, { status: 404 })
    }

    const materialCount = sourceTemplate._count.materials

    if (materialCount === 0) {
      return NextResponse.json({ 
        success: true,
        migratedCount: 0,
        message: '没有需要迁移的素材',
      })
    }

    console.log('[TemplateMigrate] Starting migration:', {
      sourceTemplateId,
      sourceTemplateName: sourceTemplate.name,
      targetTemplateId,
      targetTemplateName: targetTemplate.name,
      materialCount,
      updateMaterialType,
    })

    // 构建更新数据
    const updateData: any = {
      templateId: targetTemplateId,
    }

    // 如果需要更新 materialType
    if (updateMaterialType && targetTemplate.materialType) {
      updateData.materialType = targetTemplate.materialType
    }

    // 批量更新素材
    const result = await prisma.material.updateMany({
      where: { templateId: sourceTemplateId },
      data: updateData,
    })

    console.log('[TemplateMigrate] Migration completed:', {
      sourceTemplateId,
      targetTemplateId,
      migratedCount: result.count,
    })

    return NextResponse.json({
      success: true,
      migratedCount: result.count,
      message: `成功将 ${result.count} 个素材从"${sourceTemplate.name}"迁移到"${targetTemplate.name}"`,
      sourceTemplate: {
        id: sourceTemplate.id,
        name: sourceTemplate.name,
      },
      targetTemplate: {
        id: targetTemplate.id,
        name: targetTemplate.name,
      },
    })
  } catch (error: any) {
    console.error('[TemplateMigrate] Migration error:', {
      sourceTemplateId: params.id,
      error: error?.message,
      stack: error?.stack,
    })

    return NextResponse.json({ 
      error: error?.message || '迁移失败',
      errorCode: 'MIGRATION_FAILED',
    }, { status: 500 })
  }
}