MeBox/internal/service/favorites_sync.go

package service

import (
	"context"
	"errors"

	"gorm.io/gorm"

	"github.com/truewhile/MeBox/internal/model"
	"github.com/truewhile/MeBox/internal/repository"
)

// SyncUserFavorite keeps favourite state in the local favourites table, keyed
// by MeBox user_id. Remote Emby mounts share one upstream account, so favourite
// state is intentionally not proxied upstream.
func SyncUserFavorite(ctx context.Context, repo *repository.Container, _ *EmbyRemoteService, userID, mediaID string, favorite bool) error {
	if repo == nil || userID == "" || mediaID == "" {
		return errors.New("missing favourite sync inputs")
	}
	return setLocalFavorite(ctx, repo, userID, mediaID, favorite)
}

// IsUserFavorite reports whether the user has favourited mediaID locally.
func IsUserFavorite(ctx context.Context, repo *repository.Container, userID, mediaID string) (bool, error) {
	if repo == nil || userID == "" || mediaID == "" {
		return false, nil
	}
	var count int64
	err := repo.DB.WithContext(ctx).Model(&model.Favorite{}).
		Where("user_id = ? AND media_id = ?", userID, mediaID).
		Count(&count).Error
	return count > 0, err
}

func setLocalFavorite(ctx context.Context, repo *repository.Container, userID, mediaID string, favorite bool) error {
	if favorite {
		var existing model.Favorite
		// 收藏行的删除是软删除；重新收藏时必须连已软删除的行一起查出来，
		// 否则会再次插入同一 (user_id, media_id)，撞上唯一索引后稳定返回
		// 500，用户表现为“取消收藏后无法再收藏”。
		err := repo.DB.WithContext(ctx).Unscoped().
			Where("user_id = ? AND media_id = ?", userID, mediaID).
			First(&existing).Error
		switch {
		case errors.Is(err, gorm.ErrRecordNotFound):
			return repo.DB.WithContext(ctx).Create(&model.Favorite{
				UserID:  userID,
				MediaID: mediaID,
			}).Error
		case err != nil:
			return err
		case existing.DeletedAt.Valid:
			return repo.DB.WithContext(ctx).Unscoped().
				Model(&model.Favorite{}).
				Where("id = ?", existing.ID).
				Update("deleted_at", nil).Error
		default:
			return nil
		}
	}
	return repo.DB.WithContext(ctx).
		Where("user_id = ? AND media_id = ?", userID, mediaID).
		Delete(&model.Favorite{}).Error
}