package entity

import (
	"errors"
	"time"

	"backend/pkg/post/domain/post"

	"github.com/gocql/gocql"
)

// Comment represents a comment entity on a post.
// Comments can be nested (replies to comments).
type Comment struct {
	ID         gocql.UUID         `db:"id" partition_key:"true"`                   // Comment unique identifier
	PostID     gocql.UUID         `db:"post_id" clustering_key:"true"`             // Post ID (clustering key for sorting)
	AuthorUID  string             `db:"author_uid"`                                // Author user UID
	ParentID   *gocql.UUID        `db:"parent_id,omitempty" clustering_key:"true"` // Parent comment ID (for nested comments)
	Content    string             `db:"content"`                                   // Comment content
	Status     post.CommentStatus `db:"status"`                                    // Comment status
	LikeCount  int64              `db:"like_count"`                                // Number of likes
	ReplyCount int64              `db:"reply_count"`                               // Number of replies
	CreatedAt  int64              `db:"created_at" clustering_key:"true"`          // Creation timestamp (for sorting)
	UpdatedAt  int64              `db:"updated_at"`                                // Last update timestamp
}

// TableName returns the Cassandra table name for Comment entities.
func (c *Comment) TableName() string {
	return "comments"
}

// Validate validates the Comment entity
func (c *Comment) Validate() error {
	var zeroUUID gocql.UUID
	if c.PostID == zeroUUID {
		return errors.New("post_id is required")
	}
	if c.AuthorUID == "" {
		return errors.New("author_uid is required")
	}
	if len(c.Content) < 1 || len(c.Content) > 2000 {
		return errors.New("content length must be between 1 and 2000 characters")
	}
	if !c.Status.IsValid() {
		return errors.New("invalid comment status")
	}
	return nil
}

// SetTimestamps sets the create and update timestamps
func (c *Comment) SetTimestamps() {
	now := time.Now().UTC().UnixNano() / 1e6 // milliseconds
	if c.CreatedAt == 0 {
		c.CreatedAt = now
	}
	c.UpdatedAt = now
}

// IsNew returns true if this is a new comment (no ID set)
func (c *Comment) IsNew() bool {
	var zeroUUID gocql.UUID
	return c.ID == zeroUUID
}

// IsReply returns true if this comment is a reply to another comment
func (c *Comment) IsReply() bool {
	var zeroUUID gocql.UUID
	return c.ParentID != nil && *c.ParentID != zeroUUID
}

// Delete marks the comment as deleted (soft delete)
func (c *Comment) Delete() {
	c.Status = post.CommentStatusDeleted
	c.SetTimestamps()
}

// Hide hides the comment
func (c *Comment) Hide() {
	c.Status = post.CommentStatusHidden
	c.SetTimestamps()
}

// IsVisible returns true if the comment is visible to public
func (c *Comment) IsVisible() bool {
	return c.Status.IsVisible()
}

// IncrementLikeCount increments the like count
func (c *Comment) IncrementLikeCount() {
	c.LikeCount++
	c.SetTimestamps()
}

// DecrementLikeCount decrements the like count
func (c *Comment) DecrementLikeCount() {
	if c.LikeCount > 0 {
		c.LikeCount--
		c.SetTimestamps()
	}
}

// IncrementReplyCount increments the reply count
func (c *Comment) IncrementReplyCount() {
	c.ReplyCount++
	c.SetTimestamps()
}

// DecrementReplyCount decrements the reply count
func (c *Comment) DecrementReplyCount() {
	if c.ReplyCount > 0 {
		c.ReplyCount--
		c.SetTimestamps()
	}
}