import { NextRequest, NextResponse } from 'next/server'
import { prisma } from '@/lib/prisma'
import { verifyToken } from '@/lib/auth'

// 获取购物车
export async function GET(request: NextRequest) {
  try {
    const authHeader = request.headers.get('authorization')
    if (!authHeader || !authHeader.startsWith('Bearer ')) {
      return NextResponse.json(
        { message: '请先登录' },
        { status: 401 }
      )
    }

    const token = authHeader.substring(7)
    const decoded = verifyToken(token)
    if (!decoded) {
      return NextResponse.json(
        { message: '登录已过期' },
        { status: 401 }
      )
    }

    const cartItems = await prisma.cartItem.findMany({
      where: { userId: decoded.userId },
      include: {
        component: {
          include: {
            componentType: true
          }
        }
      },
      orderBy: { createdAt: 'desc' }
    })

    return NextResponse.json(cartItems)
  } catch (error) {
    console.error('获取购物车失败:', error)
    return NextResponse.json(
      { message: '获取购物车失败' },
      { status: 500 }
    )
  }
}

// 添加商品到购物车
export async function POST(request: NextRequest) {
  try {
    const authHeader = request.headers.get('authorization')
    if (!authHeader || !authHeader.startsWith('Bearer ')) {
      return NextResponse.json(
        { message: '请先登录' },
        { status: 401 }
      )
    }

    const token = authHeader.substring(7)
    const decoded = verifyToken(token)
    if (!decoded) {
      return NextResponse.json(
        { message: '登录已过期' },
        { status: 401 }
      )
    }

    const { componentId, quantity = 1 } = await request.json()

    if (!componentId) {
      return NextResponse.json(
        { message: '缺少商品ID' },
        { status: 400 }
      )
    }

    // 检查商品是否存在
    const component = await prisma.component.findUnique({
      where: { id: componentId }
    })

    if (!component) {
      return NextResponse.json(
        { message: '商品不存在' },
        { status: 404 }
      )
    }

    if (component.stock < quantity) {
      return NextResponse.json(
        { message: '库存不足' },
        { status: 400 }
      )
    }

    // 检查购物车中是否已存在该商品
    const existingCartItem = await prisma.cartItem.findUnique({
      where: {
        userId_componentId: {
          userId: decoded.userId,
          componentId: componentId
        }
      }
    })

    let cartItem

    if (existingCartItem) {
      // 更新数量
      const newQuantity = existingCartItem.quantity + quantity
      if (newQuantity > component.stock) {
        return NextResponse.json(
          { message: '超出库存限制' },
          { status: 400 }
        )
      }

      cartItem = await prisma.cartItem.update({
        where: { id: existingCartItem.id },
        data: { quantity: newQuantity },
        include: {
          component: {
            include: {
              componentType: true
            }
          }
        }
      })
    } else {
      // 创建新的购物车项
      cartItem = await prisma.cartItem.create({
        data: {
          userId: decoded.userId,
          componentId: componentId,
          quantity: quantity
        },
        include: {
          component: {
            include: {
              componentType: true
            }
          }
        }
      })
    }

    return NextResponse.json(cartItem, { status: 201 })
  } catch (error) {
    console.error('添加到购物车失败:', error)
    return NextResponse.json(
      { message: '添加到购物车失败' },
      { status: 500 }
    )
  }
}

// 清空购物车
export async function DELETE(request: NextRequest) {
  try {
    const authHeader = request.headers.get('authorization')
    if (!authHeader || !authHeader.startsWith('Bearer ')) {
      return NextResponse.json(
        { message: '请先登录' },
        { status: 401 }
      )
    }

    const token = authHeader.substring(7)
    const decoded = verifyToken(token)
    if (!decoded) {
      return NextResponse.json(
        { message: '登录已过期' },
        { status: 401 }
      )
    }

    await prisma.cartItem.deleteMany({
      where: { userId: decoded.userId }
    })

    return NextResponse.json({ message: '购物车已清空' })
  } catch (error) {
    console.error('清空购物车失败:', error)
    return NextResponse.json(
      { message: '清空购物车失败' },
      { status: 500 }
    )
  }
}