class ResourceTypeField

abstract class ResourceTypeField {
    
    /**
     * The internal field name.
     *
     * @var string
     */
    protected $internalName;
    
    /**
     * The public field name.
     *
     * @var string
     */
    protected $publicName;
    
    /**
     * Whether the field is disabled.
     *
     * @var bool
     */
    protected $enabled;
    
    /**
     * Whether the field can only have one value.
     *
     * @var bool
     */
    protected $hasOne;
    
    /**
     * ResourceTypeField constructor.
     *
     * @param string $internal_name
     *   The internal field name.
     * @param string $public_name
     *   (optional) The public field name. Defaults to the internal field name.
     * @param bool $enabled
     *   (optional) Whether the field is enabled. Defaults to TRUE.
     * @param bool $has_one
     *   (optional) Whether the field can only have ony value. Defaults to TRUE.
     */
    public function __construct($internal_name, $public_name = NULL, $enabled = TRUE, $has_one = TRUE) {
        $this->internalName = $internal_name;
        $this->publicName = $public_name ?: $internal_name;
        $this->enabled = $enabled;
        $this->hasOne = $has_one;
    }
    
    /**
     * Gets the internal name of the field.
     *
     * @return string
     *   The internal name of the field.
     */
    public function getInternalName() {
        return $this->internalName;
    }
    
    /**
     * Gets the public name of the field.
     *
     * @return string
     *   The public name of the field.
     */
    public function getPublicName() {
        return $this->publicName;
    }
    
    /**
     * Establishes a new public name for the field.
     *
     * @param string $public_name
     *   The public name.
     *
     * @return static
     *   A new instance of the field with the given public name.
     */
    public function withPublicName($public_name) {
        return new static($this->internalName, $public_name, $this->enabled, $this->hasOne);
    }
    
    /**
     * Gets a new instance of the field that is disabled.
     *
     * @return static
     *   A new instance of the field that is disabled.
     */
    public function disabled() {
        return new static($this->internalName, $this->publicName, FALSE, $this->hasOne);
    }
    
    /**
     * Whether the field is enabled.
     *
     * @return bool
     *   Whether the field is enabled. FALSE if the field should not be in the
     *   JSON:API response.
     */
    public function isFieldEnabled() {
        return $this->enabled;
    }
    
    /**
     * Whether the field can only have one value.
     *
     * @return bool
     *   TRUE if the field can have only one value, FALSE otherwise.
     */
    public function hasOne() {
        return $this->hasOne;
    }
    
    /**
     * Whether the field can have many values.
     *
     * @return bool
     *   TRUE if the field can have more than one value, FALSE otherwise.
     */
    public function hasMany() {
        return !$this->hasOne;
    }

}