h ( $actions as $rel ) {
					$response->add_link( $rel, $self );
				}
			}
		}

		return $response;
	}

	/**
	 * Prepares links for the request.
	 *
	 * @since 5.9.0
	 * @since 6.3.0 Adds revisions count and rest URL href to version-history.
	 *
	 * @param integer $id ID.
	 * @return array Links for the given post.
	 */
	protected function prepare_links( $id ) {
		$base = sprintf( '%s/%s', $this->namespace, $this->rest_base );

		$links = array(
			'self' => array(
				'href' => rest_url( trailingslashit( $base ) . $id ),
			),
		);

		if ( post_type_supports( $this->post_type, 'revisions' ) ) {
			$revisions                = wp_get_latest_revision_id_and_total_count( $id );
			$revisions_count          = ! is_wp_error( $revisions ) ? $revisions['count'] : 0;
			$revisions_base           = sprintf( '/%s/%d/revisions', $base, $id );
			$links['version-history'] = array(
				'href'  => rest_url( $revisions_base ),
				'count' => $revisions_count,
			);
		}

		return $links;
	}

	/**
	 * Get the link relations available for the post and current user.
	 *
	 * @since 5.9.0
	 * @since 6.2.0 Added 'edit-css' action.
	 *
	 * @return array List of link relations.
	 */
	protected function get_available_actions() {
		$rels = array();

		$post_type = get_post_type_object( $this->post_type );
		if ( current_user_can( $post_type->cap->publish_posts ) ) {
			$rels[] = 'https://api.w.org/action-publish';
		}

		if ( current_user_can( 'edit_css' ) ) {
			$rels[] = 'https://api.w.org/action-edit-css';
		}

		return $rels;
	}

	/**
	 * Overwrites the default protected title format.
	 *
	 * By default, WordPress will show password protected posts with a title of
	 * "Protected: %s", as the REST API communicates the protected status of a post
	 * in a machine readable format, we remove the "Protected: " prefix.
	 *
	 * @since 5.9.0
	 *
	 * @return string Protected title format.
	 */
	public function protected_title_format() {
		return '%s';
	}

	/**
	 * Retrieves the query params for the global styles collection.
	 *
	 * @since 5.9.0
	 *
	 * @return array Collection parameters.
	 */
	public function get_collection_params() {
		return array();
	}

	/**
	 * Retrieves the global styles type' schema, conforming to JSON Schema.
	 *
	 * @since 5.9.0
	 *
	 * @return array Item schema data.
	 */
	public function get_item_schema() {
		if ( $this->schema ) {
			return $this->add_additional_fields_schema( $this->schema );
		}

		$schema = array(
			'$schema'    => 'http://json-schema.org/draft-04/schema#',
			'title'      => $this->post_type,
			'type'       => 'object',
			'properties' => array(
				'id'       => array(
					'description' => __( 'ID of global styles config.' ),
					'type'        => 'string',
					'context'     => array( 'embed', 'view', 'edit' ),
					'readonly'    => true,
				),
				'styles'   => array(
					'description' => __( 'Global styles.' ),
					'type'        => array( 'object' ),
					'context'     => array( 'view', 'edit' ),
				),
				'settings' => array(
					'description' => __( 'Global settings.' ),
					'type'        => array( 'object' ),
					'context'     => array( 'view', 'edit' ),
				),
				'title'    => array(
					'description' => __( 'Title of the global styles variation.' ),
					'type'        => array( 'object', 'string' ),
					'default'     => '',
					'context'     => array( 'embed', 'view', 'edit' ),
					'properties'  => array(
						'raw'      => array(
							'description' => __( 'Title for the global styles variation, as it exists in the database.' ),
							'type'        => 'string',
							'context'     => array( 'view', 'edit', 'embed' ),
						),
						'rendered' => array(
							'description' => __( 'HTML title for the post, transformed for display.' ),
							'type'        => 'string',
							'context'     => array( 'view', 'edit', 'embed' ),
							'readonly'    => true,
						),
					),
				),
			),
		);

		$this->schema = $schema;

		return $this->add_additional_fields_schema( $this->schema );
	}

	/**
	 * Checks if a given request has access to read a single theme global styles config.
	 *
	 * @since 5.9.0
	 *
	 * @param WP_REST_Request $request Full details about the request.
	 * @return true|WP_Error True if the request has read access for the item, WP_Error object otherwise.
	 */
	public function get_theme_item_permissions_check( $request ) {
		/*
		 * Verify if the current user has edit_theme_options capability.
		 * This capability is required to edit/view/delete templates.
		 */
		if ( ! current_user_can( 'edit_theme_options' ) ) {
			return new WP_Error(
				'rest_cannot_manage_global_styles',
				__( 'Sorry, you are not allowed to access the global styles on this site.' ),
				array(
					'status' => rest_authorization_required_code(),
				)
			);
		}

		return true;
	}

	/**
	 * Returns the given theme global styles config.
	 *
	 * @since 5.9.0
	 *
	 * @param WP_REST_Request $request The request instance.
	 * @return WP_REST_Response|WP_Error
	 */
	public function get_theme_item( $request ) {
		if ( get_stylesheet() !== $request['stylesheet'] ) {
			// This endpoint only supports the active theme for now.
			return new WP_Error(
				'rest_theme_not_found',
				__( 'Theme not found.' ),
				array( 'status' => 404 )
			);
		}

		$theme  = WP_Theme_JSON_Resolver::get_merged_data( 'theme' );
		$fields = $this->get_fields_for_response( $request );
		$data   = array();

		if ( rest_is_field_included( 'settings', $fields ) ) {
			$data['settings'] = $theme->get_settings();
		}

		if ( rest_is_field_included( 'styles', $fields ) ) {
			$raw_data       = $theme->get_raw_data();
			$data['styles'] = isset( $raw_data['styles'] ) ? $raw_data['styles'] : array();
		}

		$context = ! empty( $request['context'] ) ? $request['context'] : 'view';
		$data    = $this->add_additional_fields_to_object( $data, $request );
		$data    = $this->filter_response_by_context( $data, $context );

		$response = rest_ensure_response( $data );

		if ( rest_is_field_included( '_links', $fields ) || rest_is_field_included( '_embedded', $fields ) ) {
			$links = array(
				'self' => array(
					'href' => rest_url( sprintf( '%s/%s/themes/%s', $this->namespace, $this->rest_base, $request['stylesheet'] ) ),
				),
			);
			$response->add_links( $links );
		}

		return $response;
	}

	/**
	 * Checks if a given request has access to read a single theme global styles config.
	 *
	 * @since 6.0.0
	 *
	 * @param WP_REST_Request $request Full details about the request.
	 * @return true|WP_Error True if the request has read access for the item, WP_Error object otherwise.
	 */
	public function get_theme_items_permissions_check( $request ) {
		/*
		 * Verify if the current user has edit_theme_options capability.
		 * This capability is required to edit/view/delete templates.
		 */
		if ( ! current_user_can( 'edit_theme_options' ) ) {
			return new WP_Error(
				'rest_cannot_manage_global_styles',
				__( 'Sorry, you are not allowed to access the global styles on this site.' ),
				array(
					'status' => rest_authorization_required_code(),
				)
			);
		}

		return true;
	}

	/**
	 * Returns the given theme global styles variations.
	 *
	 * @since 6.0.0
	 * @since 6.2.0 Returns parent theme variations, if they exist.
	 *
	 * @param WP_REST_Request $request The request instance.
	 *
	 * @return WP_REST_Response|WP_Error
	 */
	public function get_theme_items( $request ) {
		if ( get_stylesheet() !== $request['stylesheet'] ) {
			// This endpoint only supports the active theme for now.
			return new WP_Error(
				'rest_theme_not_found',
				__( 'Theme not found.' ),
				array( 'status' => 404 )
			);
		}

		$variations = WP_Theme_JSON_Resolver::get_style_variations();

		return rest_ensure_response( $variations );
	}

	/**
	 * Validate style.css as valid CSS.
	 *
	 * Currently just checks for invalid markup.
	 *
	 * @since 6.2.0
	 * @since 6.4.0 Changed method visibility to protected.
	 *
	 * @param string $css CSS to validate.
	 * @return true|WP_Error True if the input was validated, otherwise WP_Error.
	 */
	protected function validate_custom_css( $css ) {
		if ( preg_match( '#</?\w+#', $css ) ) {
			return new WP_Error(
				'rest_custom_css_illegal_markup',
				__( 'Markup is not allowed in CSS.' ),
				array( 'status' => 400 )
			);
		}
		return true;
	}
}