backend/internal/service/sticker_service.go

package service

import (
	"carrot_bbs/internal/model"
	"carrot_bbs/internal/repository"
	"errors"
	"net/url"
	"strings"
)

var (
	ErrStickerAlreadyExists = errors.New("sticker already exists")
	ErrInvalidStickerURL    = errors.New("invalid sticker url")
)

// StickerService 自定义表情服务接口
type StickerService interface {
	// 获取用户的所有表情
	GetUserStickers(userID string) ([]model.UserSticker, error)
	// 添加表情
	AddSticker(userID string, url string, width, height int) (*model.UserSticker, error)
	// 删除表情
	DeleteSticker(userID string, stickerID string) error
	// 检查表情是否已存在
	CheckExists(userID string, url string) (bool, error)
	// 重新排序
	ReorderStickers(userID string, orders map[string]int) error
	// 获取用户表情数量
	GetStickerCount(userID string) (int64, error)
}

// stickerService 自定义表情服务实现
type stickerService struct {
	stickerRepo repository.StickerRepository
}

// NewStickerService 创建自定义表情服务
func NewStickerService(stickerRepo repository.StickerRepository) StickerService {
	return &stickerService{
		stickerRepo: stickerRepo,
	}
}

// GetUserStickers 获取用户的所有表情
func (s *stickerService) GetUserStickers(userID string) ([]model.UserSticker, error) {
	stickers, err := s.stickerRepo.GetByUserID(userID)
	if err != nil {
		return nil, err
	}

	// 兼容历史脏数据：过滤本地文件 URI，避免客户端加载 file:// 报错
	filtered := make([]model.UserSticker, 0, len(stickers))
	for _, sticker := range stickers {
		if isValidStickerURL(sticker.URL) {
			filtered = append(filtered, sticker)
		}
	}
	return filtered, nil
}

// AddSticker 添加表情
func (s *stickerService) AddSticker(userID string, url string, width, height int) (*model.UserSticker, error) {
	if !isValidStickerURL(url) {
		return nil, ErrInvalidStickerURL
	}

	// 检查是否已存在
	exists, err := s.stickerRepo.Exists(userID, url)
	if err != nil {
		return nil, err
	}
	if exists {
		return nil, ErrStickerAlreadyExists
	}

	// 获取当前数量用于设置排序
	count, err := s.stickerRepo.CountByUserID(userID)
	if err != nil {
		return nil, err
	}

	sticker := &model.UserSticker{
		UserID:    userID,
		URL:       url,
		Width:     width,
		Height:    height,
		SortOrder: int(count), // 新表情添加到末尾
	}

	if err := s.stickerRepo.Create(sticker); err != nil {
		return nil, err
	}

	return sticker, nil
}

func isValidStickerURL(raw string) bool {
	trimmed := strings.TrimSpace(raw)
	if trimmed == "" {
		return false
	}

	parsed, err := url.Parse(trimmed)
	if err != nil {
		return false
	}

	scheme := strings.ToLower(parsed.Scheme)
	return scheme == "http" || scheme == "https"
}

// DeleteSticker 删除表情
func (s *stickerService) DeleteSticker(userID string, stickerID string) error {
	// 先检查表情是否属于该用户
	sticker, err := s.stickerRepo.GetByID(stickerID)
	if err != nil {
		return err
	}
	if sticker.UserID != userID {
		return errors.New("sticker not found")
	}

	return s.stickerRepo.Delete(stickerID)
}

// CheckExists 检查表情是否已存在
func (s *stickerService) CheckExists(userID string, url string) (bool, error) {
	return s.stickerRepo.Exists(userID, url)
}

// ReorderStickers 重新排序
func (s *stickerService) ReorderStickers(userID string, orders map[string]int) error {
	return s.stickerRepo.BatchUpdateSortOrder(userID, orders)
}

// GetStickerCount 获取用户表情数量
func (s *stickerService) GetStickerCount(userID string) (int64, error) {
	return s.stickerRepo.CountByUserID(userID)
}