<?php

if ( ! class_exists( 'WP_Icons_Registry' ) ) {
	class WP_Icons_Registry {
		/**
		 * Registered icons array.
		 *
		 * @var array[]
		 */
		protected $registered_icons = array();


		/**
		 * Container for the main instance of the class.
		 *
		 * @var WP_Icons_Registry|null
		 */
		protected static $instance = null;

		/**
		 * Constructor.
		 *
		 * WP_Icons_Registry is a singleton class, so keep this protected.
		 *
		 * For WP 7.0, the Icons Registry is closed for third-party icon
		 * registry, serving only a subset of core icons.
		 *
		 * These icons are defined in @wordpress/packages as SVG files and as
		 * entries in a single manifest file. On init, the registry is loaded
		 * with those icons listed in the manifest.
		 */
		protected function __construct() {
			$icons_directory = __DIR__ . '/../../../packages/icons/src/';
			$icons_directory = trailingslashit( $icons_directory );
			$manifest_path   = $icons_directory . 'manifest.php';

			if ( ! is_readable( $manifest_path ) ) {
				wp_trigger_error(
					__METHOD__,
					__( 'Core icon collection manifest is missing or unreadable.', 'gutenberg' )
				);
				return;
			}

			$collection = include $manifest_path;

			if ( empty( $collection ) ) {
				wp_trigger_error(
					__METHOD__,
					__( 'Core icon collection manifest is empty or invalid.', 'gutenberg' )
				);
				return;
			}

			foreach ( $collection as $icon_name => $icon_data ) {
				if (
					empty( $icon_data['filePath'] )
					|| ! is_string( $icon_data['filePath'] )
				) {
					_doing_it_wrong(
						__METHOD__,
						__( 'Core icon collection manifest must provide valid a "filePath" for each icon.', 'gutenberg' ),
						'7.0.0'
					);
					return;
				}

				$this->register(
					'core/' . $icon_name,
					array(
						'label'    => $icon_data['label'],
						'filePath' => $icons_directory . $icon_data['filePath'],
					)
				);
			}
		}

		/**
		 * Registers an icon.
		 *
		 * @param string $icon_name       Icon name including namespace.
		 * @param array  $icon_properties {
		 *     List of properties for the icon.
		 *
		 *     @type string $label    Required. A human-readable label for the icon.
		 *     @type string $content  Optional. SVG markup for the icon.
		 *                            If not provided, the content will be retrieved from the `filePath` if set.
		 *                            If both `content` and `filePath` are not set, the icon will not be registered.
		 *     @type string $filePath Optional. The full path to the file containing the icon content.
		 * }
		 * @return bool True if the icon was registered with success and false otherwise.
		 */
		protected function register( $icon_name, $icon_properties ) {
			if ( ! isset( $icon_name ) || ! is_string( $icon_name ) ) {
				_doing_it_wrong(
					__METHOD__,
					__( 'Icon name must be a string.', 'gutenberg' ),
					'7.0.0'
				);
				return false;
			}

			$allowed_keys = array_fill_keys( array( 'label', 'content', 'filePath' ), 1 );
			foreach ( array_keys( $icon_properties ) as $key ) {
				if ( ! array_key_exists( $key, $allowed_keys ) ) {
					_doing_it_wrong(
						__METHOD__,
						sprintf(
							// translators: %s is the name of any user-provided key
							__( 'Invalid icon property: "%s".', 'gutenberg' ),
							$key
						),
						'7.0.0'
					);
					return false;
				}
			}

			if ( ! isset( $icon_properties['label'] ) || ! is_string( $icon_properties['label'] ) ) {
				_doing_it_wrong(
					__METHOD__,
					__( 'Icon label must be a string.', 'gutenberg' ),
					'7.0.0'
				);
				return false;
			}

			if (
				( ! isset( $icon_properties['content'] ) && ! isset( $icon_properties['filePath'] ) ) ||
				( isset( $icon_properties['content'] ) && isset( $icon_properties['filePath'] ) )
			) {
				_doing_it_wrong(
					__METHOD__,
					__( 'Icons must provide either `content` or `filePath`.', 'gutenberg' ),
					'7.0.0'
				);
				return false;
			}

			if ( isset( $icon_properties['content'] ) ) {
				if ( ! is_string( $icon_properties['content'] ) ) {
					_doing_it_wrong(
						__METHOD__,
						__( 'Icon content must be a string.', 'gutenberg' ),
						'7.0.0'
					);
					return false;
				}

				$sanitized_icon_content = $this->sanitize_icon_content( $icon_properties['content'] );
				if ( empty( $sanitized_icon_content ) ) {
					_doing_it_wrong(
						__METHOD__,
						__( 'Icon content does not contain valid SVG markup.', 'gutenberg' ),
						'7.0.0'
					);
					return false;
				}
			}

			$icon = array_merge(
				$icon_properties,
				array( 'name' => $icon_name )
			);

			$this->registered_icons[ $icon_name ] = $icon;

			return true;
		}

		/**
		 * Sanitizes the icon SVG content.
		 *
		 * Logic borrowed from twentytwenty.
		 * @see twentytwenty_get_theme_svg
		 *
		 * @param string $icon_content The icon SVG content to sanitize.
		 * @return string The sanitized icon SVG content.
		 */
		protected function sanitize_icon_content( $icon_content ) {
			$allowed_tags = array(
				'svg'     => array(
					'class'       => true,
					'xmlns'       => true,
					'width'       => true,
					'height'      => true,
					'viewbox'     => true,
					'aria-hidden' => true,
					'role'        => true,
					'focusable'   => true,
				),
				'path'    => array(
					'fill'      => true,
					'fill-rule' => true,
					'd'         => true,
					'transform' => true,
				),
				'polygon' => array(
					'fill'      => true,
					'fill-rule' => true,
					'points'    => true,
					'transform' => true,
					'focusable' => true,
				),
			);
			return wp_kses( $icon_content, $allowed_tags );
		}

		/**
		 * Retrieves the content of a registered icon.
		 *
		 * @param string $icon_name Icon name including namespace.
		 * @return string|null The content of the icon, if found.
		 */
		protected function get_content( $icon_name ) {
			if ( ! isset( $this->registered_icons[ $icon_name ]['content'] ) ) {
				$content = file_get_contents(
					$this->registered_icons[ $icon_name ]['filePath']
				);
				$content = $this->sanitize_icon_content( $content );

				if ( empty( $content ) ) {
					wp_trigger_error(
						__METHOD__,
						__( 'Icon content does not contain valid SVG markup.', 'gutenberg' )
					);
					return null;
				}

				$this->registered_icons[ $icon_name ]['content'] = $content;
			}
			return $this->registered_icons[ $icon_name ]['content'];
		}

		/**
		 * Retrieves an array containing the properties of a registered icon.
		 *
		 *
		 * @param string $icon_name Icon name including namespace.
		 * @return array|null Registered icon properties or `null` if the icon is not registered.
		 */
		public function get_registered_icon( $icon_name ) {
			if ( ! $this->is_registered( $icon_name ) ) {
				return null;
			}

			$icon            = $this->registered_icons[ $icon_name ];
			$icon['content'] = $icon['content'] ?? $this->get_content( $icon_name );

			return $icon;
		}

		/**
		 * Retrieves all registered icons.
		 *
		 * @param string $search Optional. Search term by which to filter the icons.
		 * @return array[] Array of arrays containing the registered icon properties.
		 */
		public function get_registered_icons( $search = '' ) {
			$icons = array();

			foreach ( $this->registered_icons as $icon ) {
				if ( ! empty( $search ) && false === stripos( $icon['name'], $search ) ) {
					continue;
				}

				$icon['content'] = $icon['content'] ?? $this->get_content( $icon['name'] );
				$icons[]         = $icon;
			}

			return $icons;
		}

		/**
		 * Checks if an icon is registered.
		 *
		 *
		 * @param string $icon_name Icon name including namespace.
		 * @return bool True if the icon is registered, false otherwise.
		 */
		public function is_registered( $icon_name ) {
			return isset( $this->registered_icons[ $icon_name ] );
		}

		/**
		 * Utility method to retrieve the main instance of the class.
		 *
		 * The instance will be created if it does not exist yet.
		 *
		 *
		 * @return WP_Icons_Registry The main instance.
		 */
		public static function get_instance() {
			if ( null === self::$instance ) {
				self::$instance = new self();
			}

			return self::$instance;
		}
	}
}