backend/pkg/post/domain/usecase/comment.go

package usecase

import (
	"context"

	"backend/pkg/post/domain/post"

	"github.com/gocql/gocql"
)

// CommentUseCase defines the interface for comment business logic operations
type CommentUseCase interface {
	CommentCRUDUseCase
	CommentQueryUseCase
	CommentInteractionUseCase
}

// CommentCRUDUseCase defines CRUD operations for comments
type CommentCRUDUseCase interface {
	// CreateComment creates a new comment
	CreateComment(ctx context.Context, req CreateCommentRequest) (*CommentResponse, error)
	// GetComment retrieves a comment by ID
	GetComment(ctx context.Context, req GetCommentRequest) (*CommentResponse, error)
	// UpdateComment updates an existing comment
	UpdateComment(ctx context.Context, req UpdateCommentRequest) (*CommentResponse, error)
	// DeleteComment deletes a comment (soft delete)
	DeleteComment(ctx context.Context, req DeleteCommentRequest) error
}

// CommentQueryUseCase defines query operations for comments
type CommentQueryUseCase interface {
	// ListComments lists comments for a post
	ListComments(ctx context.Context, req ListCommentsRequest) (*ListCommentsResponse, error)
	// ListReplies lists replies to a comment
	ListReplies(ctx context.Context, req ListRepliesRequest) (*ListCommentsResponse, error)
	// ListCommentsByAuthor lists comments by author
	ListCommentsByAuthor(ctx context.Context, req ListCommentsByAuthorRequest) (*ListCommentsResponse, error)
}

// CommentInteractionUseCase defines interaction operations for comments
type CommentInteractionUseCase interface {
	// LikeComment likes a comment
	LikeComment(ctx context.Context, req LikeCommentRequest) error
	// UnlikeComment unlikes a comment
	UnlikeComment(ctx context.Context, req UnlikeCommentRequest) error
}

// CreateCommentRequest represents a request to create a comment
type CreateCommentRequest struct {
	PostID    gocql.UUID  `json:"post_id"`             // Post ID
	AuthorUID string      `json:"author_uid"`          // Author user UID
	ParentID  *gocql.UUID `json:"parent_id,omitempty"` // Parent comment ID (optional, for replies)
	Content   string      `json:"content"`             // Comment content
}

// UpdateCommentRequest represents a request to update a comment
type UpdateCommentRequest struct {
	CommentID gocql.UUID `json:"comment_id"` // Comment ID
	AuthorUID string     `json:"author_uid"` // Author user UID (for authorization)
	Content   string     `json:"content"`    // Comment content
}

// GetCommentRequest represents a request to get a comment
type GetCommentRequest struct {
	CommentID gocql.UUID `json:"comment_id"` // Comment ID
}

// DeleteCommentRequest represents a request to delete a comment
type DeleteCommentRequest struct {
	CommentID gocql.UUID `json:"comment_id"` // Comment ID
	AuthorUID string     `json:"author_uid"` // Author user UID (for authorization)
}

// ListCommentsRequest represents a request to list comments
type ListCommentsRequest struct {
	PostID         gocql.UUID  `json:"post_id"`                   // Post ID
	ParentID       *gocql.UUID `json:"parent_id,omitempty"`       // Parent comment ID (optional, for replies only)
	PageSize       int64       `json:"page_size"`                 // Page size
	PageIndex      int64       `json:"page_index"`                // Page index
	OrderBy        string      `json:"order_by,omitempty"`        // Order by field (default: "created_at")
	OrderDirection string      `json:"order_direction,omitempty"` // Order direction (ASC/DESC, default: ASC)
}

// ListRepliesRequest represents a request to list replies to a comment
type ListRepliesRequest struct {
	CommentID gocql.UUID `json:"comment_id"` // Comment ID
	PageSize  int64      `json:"page_size"`  // Page size
	PageIndex int64      `json:"page_index"` // Page index
}

// ListCommentsByAuthorRequest represents a request to list comments by author
type ListCommentsByAuthorRequest struct {
	AuthorUID string `json:"author_uid"` // Author UID
	PageSize  int64  `json:"page_size"`  // Page size
	PageIndex int64  `json:"page_index"` // Page index
}

// LikeCommentRequest represents a request to like a comment
type LikeCommentRequest struct {
	CommentID gocql.UUID `json:"comment_id"` // Comment ID
	UserUID   string     `json:"user_uid"`   // User UID
}

// UnlikeCommentRequest represents a request to unlike a comment
type UnlikeCommentRequest struct {
	CommentID gocql.UUID `json:"comment_id"` // Comment ID
	UserUID   string     `json:"user_uid"`   // User UID
}

// CommentResponse represents a comment response
type CommentResponse struct {
	ID         gocql.UUID         `json:"id"`
	PostID     gocql.UUID         `json:"post_id"`
	AuthorUID  string             `json:"author_uid"`
	ParentID   *gocql.UUID        `json:"parent_id,omitempty"`
	Content    string             `json:"content"`
	Status     post.CommentStatus `json:"status"`
	LikeCount  int64              `json:"like_count"`
	ReplyCount int64              `json:"reply_count"`
	CreatedAt  int64              `json:"created_at"`
	UpdatedAt  int64              `json:"updated_at"`
}

// ListCommentsResponse represents a list of comments response
type ListCommentsResponse struct {
	Data []CommentResponse `json:"data"`
	Page Pager             `json:"page"`
}