relynolli-server/storage/cart.go

package storage

import (
	"context"
	"crypto/md5"
	"encoding/hex"
	"fmt"
	"relynolli-server/internal"
	"relynolli-server/models/cart"
	"time"
)

type StorageCart interface {
	CreateFuser(ctx context.Context) (int64, *cart.DBFuser, error)
	GetCartItems(ctx context.Context, fuserId int64) (*[]cart.DBCart, error)
	GetCartItem(ctx context.Context, fuserId, productId int64) (*cart.DBCart, error)
	AddItemToCart(ctx context.Context, fuserId, productId int64) error
	UpdateCartItem(ctx context.Context, fuserId, productId, quantity int64) error
	DeleteCartItem(ctx context.Context, fuserId, productId int64) error
}

func NewStorageCart() StorageCart {
	if instance == nil {
		instance = &storage{
			db:  internal.InitDatabase().GetInstance(),
			rdb: internal.InitRedis(),
		}
	}
	return instance
}

func (s *storage) CreateFuser(ctx context.Context) (int64, *cart.DBFuser, error) {
	//stmt := "insert into b_sale_fuser (DATE_INSERT, DATE_UPDATE, CODE) values (now(), now(), md5(rand()));"
	hash := md5.Sum([]byte(fmt.Sprintf("%d", time.Now().Unix())))

	model := &cart.DBFuser{
		Code:         hex.EncodeToString(hash[:]),
		DateInserted: time.Now().UTC(),
		DateUpdated:  time.Now().UTC(),
	}

	res, err := s.db.NewInsert().Model(model).Exec(ctx)
	id, _ := res.LastInsertId()

	s.db.NewSelect().Model(model).Where("id = ?", id).Scan(ctx)

	if err != nil {
		return 0, nil, err
	}
	return model.Id, model, nil
}

func (s *storage) GetCartItems(ctx context.Context, fuserId int64) (*[]cart.DBCart, error) {
	result := new([]cart.DBCart)
	err := s.db.NewSelect().Model(result).Relation("Product").Relation("Fuser").Where("fuser_id = ?", fuserId).Scan(ctx)

	if err != nil {
		return nil, err
	}
	return result, nil
}

func (s *storage) GetCartItem(ctx context.Context, fuserId, productId int64) (*cart.DBCart, error) {
	result := new(cart.DBCart)
	err := s.db.NewSelect().Model(result).Relation("Product").Relation("Fuser").Where("fuser_id = ?", fuserId).Where("product_id = ?", productId).Scan(ctx)

	if err != nil {
		return nil, err
	}
	return result, nil
}

func (s *storage) AddItemToCart(ctx context.Context, fuserId, productId int64) error {

	item, _ := s.GetCatalogItem(ctx, &productId)
	isExists, err := s.db.NewSelect().Model((*cart.DBCart)(nil)).Where("fuser_id = ?", fuserId).Where("product_id = ?", productId).Exists(ctx)

	if isExists || item.AvailableQuantity < 1 {
		return nil
	}

	if err != nil {
		panic(err.Error())
	}

	newItem := &cart.DBCart{
		FuserId:     fuserId,
		ProductId:   productId,
		PriceTypeId: 1,
		Quantity:    1,
	}

	_, err = s.db.NewInsert().Model(newItem).Exec(ctx)

	if err != nil {
		return nil
	}

	return nil
}

func (s *storage) UpdateCartItem(ctx context.Context, fuserId, productId, quantity int64) error {
	if quantity <= 0 {
		return s.DeleteCartItem(ctx, fuserId, productId)
	}

	item, _ := s.GetCartItem(ctx, fuserId, productId)

	if item.Product.AvailableQuantity < quantity {
		return fmt.Errorf("Available quantity is less than requested. Available %d, requested %d", item.Product.AvailableQuantity, quantity)
	}

	item.Quantity = quantity

	s.db.NewUpdate().Model(item).Where("id = ?", item.Id).Exec(ctx)

	return nil
}

func (s *storage) DeleteCartItem(ctx context.Context, fuserId, productId int64) error {
	_, err := s.db.NewDelete().Model((*cart.DBCart)(nil)).Where("fuser_id = ?", fuserId).Where("product_id = ?", productId).Exec(ctx)
	if err != nil {
		return err
	}
	return nil
}