package entity

import (
	"errors"
	"time"

	"github.com/gocql/gocql"
)

// Category represents a category entity for organizing posts.
type Category struct {
	ID          gocql.UUID  `db:"id" partition_key:"true"` // Category unique identifier
	Slug        string      `db:"slug"`                    // URL-friendly slug (unique)
	Name        string      `db:"name"`                    // Category name
	Description *string     `db:"description,omitempty"`   // Category description (optional)
	ParentID    *gocql.UUID `db:"parent_id,omitempty"`     // Parent category ID (for nested categories)
	PostCount   int64       `db:"post_count"`              // Number of posts in this category
	IsActive    bool        `db:"is_active"`               // Whether the category is active
	SortOrder   int32       `db:"sort_order"`              // Sort order for display
	CreatedAt   int64       `db:"created_at"`              // Creation timestamp
	UpdatedAt   int64       `db:"updated_at"`              // Last update timestamp
}

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

// Validate validates the Category entity
func (c *Category) Validate() error {
	if c.Name == "" {
		return errors.New("category name is required")
	}
	if c.Slug == "" {
		return errors.New("category slug is required")
	}
	return nil
}

// SetTimestamps sets the create and update timestamps
func (c *Category) 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 category (no ID set)
func (c *Category) IsNew() bool {
	var zeroUUID gocql.UUID
	return c.ID == zeroUUID
}

// IsRoot returns true if this category has no parent
func (c *Category) IsRoot() bool {
	var zeroUUID gocql.UUID
	return c.ParentID == nil || *c.ParentID == zeroUUID
}

// IncrementPostCount increments the post count
func (c *Category) IncrementPostCount() {
	c.PostCount++
	c.SetTimestamps()
}

// DecrementPostCount decrements the post count
func (c *Category) DecrementPostCount() {
	if c.PostCount > 0 {
		c.PostCount--
		c.SetTimestamps()
	}
}

// Activate activates the category
func (c *Category) Activate() {
	c.IsActive = true
	c.SetTimestamps()
}

// Deactivate deactivates the category
func (c *Category) Deactivate() {
	c.IsActive = false
	c.SetTimestamps()
}