return array_keys( $wp_roles->roles );

	}

	/**
	 * Get the item schema base.
	 *
	 * @since 1.0.0-beta.27
	 *
	 * @return array
	 */
	protected function get_item_schema_base() {

		$schema = array(
			'$schema'    => 'http://json-schema.org/draft-04/schema#',
			'title'      => $this->resource_name,
			'type'       => 'object',
			'properties' => array(
				'id'                => array(
					'description' => __( 'Unique identifier for the user.', 'lifterlms' ),
					'type'        => 'integer',
					'context'     => array( 'view', 'edit' ),
					'readonly'    => true,
				),
				'username'          => array(
					'description' => __( 'Login name for the user.', 'lifterlms' ),
					'type'        => 'string',
					'context'     => array( 'edit' ),
					'arg_options' => array(
						'sanitize_callback' => array( $this, 'sanitize_username' ),
					),
				),
				'name'              => array(
					'description' => __( 'Display name for the user.', 'lifterlms' ),
					'type'        => 'string',
					'context'     => array( 'view', 'edit' ),
					'arg_options' => array(
						'sanitize_callback' => 'sanitize_text_field',
					),
				),
				'first_name'        => array(
					'description' => __( 'First name for the user.', 'lifterlms' ),
					'type'        => 'string',
					'context'     => array( 'edit' ),
					'arg_options' => array(
						'sanitize_callback' => 'sanitize_text_field',
					),
				),
				'last_name'         => array(
					'description' => __( 'Last name for the user.', 'lifterlms' ),
					'type'        => 'string',
					'context'     => array( 'edit' ),
					'arg_options' => array(
						'sanitize_callback' => 'sanitize_text_field',
					),
				),
				'email'             => array(
					'description' => __( 'The email address for the user.', 'lifterlms' ),
					'type'        => 'string',
					'format'      => 'email',
					'context'     => array( 'edit' ),
					'required'    => true,
				),
				'url'               => array(
					'description' => __( 'URL of the user.', 'lifterlms' ),
					'type'        => 'string',
					'format'      => 'uri',
					'context'     => array( 'view', 'edit' ),
				),
				'description'       => array(
					'description' => __( 'Description of the user.', 'lifterlms' ),
					'type'        => 'string',
					'context'     => array( 'view', 'edit' ),
				),
				'nickname'          => array(
					'description' => __( 'The nickname for the user.', 'lifterlms' ),
					'type'        => 'string',
					'context'     => array( 'edit' ),
					'arg_options' => array(
						'sanitize_callback' => 'sanitize_text_field',
					),
				),
				'registered_date'   => array(
					'description' => __( 'Registration date for the user.', 'lifterlms' ),
					'type'        => 'string',
					'format'      => 'date-time',
					'context'     => array( 'edit' ),
					'readonly'    => true,
				),
				'roles'             => array(
					'description' => __( 'Roles assigned to the user.', 'lifterlms' ),
					'type'        => 'array',
					'items'       => array(
						'type' => 'string',
						'enum' => $this->get_enum_roles(),
					),
					'context'     => array( 'edit' ),
					'default'     => array( 'student' ),
				),
				'password'          => array(
					'description' => __( 'Password for the user (never included).', 'lifterlms' ),
					'type'        => 'string',
					'context'     => array(), // Password is never displayed.
					'arg_options' => array(
						'sanitize_callback' => array( $this, 'sanitize_password' ),
					),
				),
				'billing_address_1' => array(
					'description' => __( 'User address line 1.', 'lifterlms' ),
					'type'        => 'string',
					'context'     => array( 'edit' ),
					'arg_options' => array(
						'sanitize_callback' => 'sanitize_text_field',
					),
				),
				'billing_address_2' => array(
					'description' => __( 'User address line 2.', 'lifterlms' ),
					'type'        => 'string',
					'context'     => array( 'edit' ),
					'arg_options' => array(
						'sanitize_callback' => 'sanitize_text_field',
					),
				),
				'billing_city'      => array(
					'description' => __( 'User address city name.', 'lifterlms' ),
					'type'        => 'string',
					'context'     => array( 'edit' ),
					'arg_options' => array(
						'sanitize_callback' => 'sanitize_text_field',
					),
				),
				'billing_state'     => array(
					'description' => __( 'User address ISO code for the state, province, or district.', 'lifterlms' ),
					'type'        => 'string',
					'context'     => array( 'edit' ),
					'arg_options' => array(
						'sanitize_callback' => 'sanitize_text_field',
					),
				),
				'billing_postcode'  => array(
					'description' => __( 'User address postal code.', 'lifterlms' ),
					'type'        => 'string',
					'context'     => array( 'edit' ),
					'arg_options' => array(
						'sanitize_callback' => 'sanitize_text_field',
					),
				),
				'billing_country'   => array(
					'description' => __( 'User address ISO code for the country.', 'lifterlms' ),
					'type'        => 'string',
					'context'     => array( 'edit' ),
					'arg_options' => array(
						'sanitize_callback' => 'sanitize_text_field',
					),
				),
			),
		);

		if ( get_option( 'show_avatars' ) ) {

			$avatar_properties = array();
			foreach ( rest_get_avatar_sizes() as $size ) {
				$avatar_properties[ $size ] = array(
					// Translators: %d = avatar image size in pixels.
					'description' => sprintf( __( 'Avatar URL with image size of %d pixels.', 'lifterlms' ), $size ),
					'type'        => 'string',
					'format'      => 'uri',
					'context'     => array( 'view', 'edit' ),
				);
			}

			$schema['properties']['avatar_urls'] = array(
				'description' => __( 'Avatar URLs for the user.', 'lifterlms' ),