feat: 添加种子数据初始化功能，重构多个处理程序以简化错误响应和用户验证

internal/service/helpers.go

@@ -0,0 +1,105 @@
+package service
+
+import (
+	"carrotskin/internal/model"
+	"carrotskin/internal/repository"
+	"errors"
+	"fmt"
+
+	"gorm.io/gorm"
+)
+
+// 通用错误
+var (
+	ErrProfileNotFound    = errors.New("档案不存在")
+	ErrProfileNoPermission = errors.New("无权操作此档案")
+	ErrTextureNotFound    = errors.New("材质不存在")
+	ErrTextureNoPermission = errors.New("无权操作此材质")
+	ErrUserNotFound       = errors.New("用户不存在")
+)
+
+// NormalizePagination 规范化分页参数
+func NormalizePagination(page, pageSize int) (int, int) {
+	if page < 1 {
+		page = 1
+	}
+	if pageSize < 1 {
+		pageSize = 20
+	}
+	if pageSize > 100 {
+		pageSize = 100
+	}
+	return page, pageSize
+}
+
+// GetProfileWithPermissionCheck 获取档案并验证权限
+// 返回档案，如果不存在或无权限则返回相应错误
+func GetProfileWithPermissionCheck(uuid string, userID int64) (*model.Profile, error) {
+	profile, err := repository.FindProfileByUUID(uuid)
+	if err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			return nil, ErrProfileNotFound
+		}
+		return nil, fmt.Errorf("查询档案失败: %w", err)
+	}
+
+	if profile.UserID != userID {
+		return nil, ErrProfileNoPermission
+	}
+
+	return profile, nil
+}
+
+// GetTextureWithPermissionCheck 获取材质并验证权限
+// 返回材质，如果不存在或无权限则返回相应错误
+func GetTextureWithPermissionCheck(textureID, userID int64) (*model.Texture, error) {
+	texture, err := repository.FindTextureByID(textureID)
+	if err != nil {
+		return nil, err
+	}
+	if texture == nil {
+		return nil, ErrTextureNotFound
+	}
+
+	if texture.UploaderID != userID {
+		return nil, ErrTextureNoPermission
+	}
+
+	return texture, nil
+}
+
+// EnsureTextureExists 确保材质存在
+func EnsureTextureExists(textureID int64) (*model.Texture, error) {
+	texture, err := repository.FindTextureByID(textureID)
+	if err != nil {
+		return nil, err
+	}
+	if texture == nil {
+		return nil, ErrTextureNotFound
+	}
+	if texture.Status == -1 {
+		return nil, errors.New("材质已删除")
+	}
+	return texture, nil
+}
+
+// EnsureUserExists 确保用户存在
+func EnsureUserExists(userID int64) (*model.User, error) {
+	user, err := repository.FindUserByID(userID)
+	if err != nil {
+		return nil, err
+	}
+	if user == nil {
+		return nil, ErrUserNotFound
+	}
+	return user, nil
+}
+
+// WrapError 包装错误，添加上下文信息
+func WrapError(err error, message string) error {
+	if err == nil {
+		return nil
+	}
+	return fmt.Errorf("%s: %w", message, err)
+}
+