1<?php
  2/**
  3 * Style Engine: WP_Style_Engine_Processor class
  4 *
  5 * @package WordPress
  6 * @subpackage StyleEngine
  7 * @since 6.1.0
  8 */
  9
 10/**
 11 * Core class used to compile styles from stores or collection of CSS rules.
 12 *
 13 * @since 6.1.0
 14 */
 15#[AllowDynamicProperties]
 16class WP_Style_Engine_Processor {
 17
 18	/**
 19	 * A collection of Style Engine Store objects.
 20	 *
 21	 * @since 6.1.0
 22	 * @var WP_Style_Engine_CSS_Rules_Store[]
 23	 */
 24	protected $stores = array();
 25
 26	/**
 27	 * The set of CSS rules that this processor will work on.
 28	 *
 29	 * @since 6.1.0
 30	 * @var WP_Style_Engine_CSS_Rule[]
 31	 */
 32	protected $css_rules = array();
 33
 34	/**
 35	 * Adds a store to the processor.
 36	 *
 37	 * @since 6.1.0
 38	 *
 39	 * @param WP_Style_Engine_CSS_Rules_Store $store The store to add.
 40	 * @return WP_Style_Engine_Processor Returns the object to allow chaining methods.
 41	 */
 42	public function add_store( $store ) {
 43		if ( ! $store instanceof WP_Style_Engine_CSS_Rules_Store ) {
 44			_doing_it_wrong(
 45				__METHOD__,
 46				__( '$store must be an instance of WP_Style_Engine_CSS_Rules_Store' ),
 47				'6.1.0'
 48			);
 49			return $this;
 50		}
 51
 52		$this->stores[ $store->get_name() ] = $store;
 53
 54		return $this;
 55	}
 56
 57	/**
 58	 * Adds rules to be processed.
 59	 *
 60	 * @since 6.1.0
 61	 * @since 6.6.0 Added support for rules_group.
 62	 *
 63	 * @param WP_Style_Engine_CSS_Rule|WP_Style_Engine_CSS_Rule[] $css_rules A single, or an array of,
 64	 *                                                                       WP_Style_Engine_CSS_Rule objects
 65	 *                                                                       from a store or otherwise.
 66	 * @return WP_Style_Engine_Processor Returns the object to allow chaining methods.
 67	 */
 68	public function add_rules( $css_rules ) {
 69		if ( ! is_array( $css_rules ) ) {
 70			$css_rules = array( $css_rules );
 71		}
 72
 73		foreach ( $css_rules as $rule ) {
 74			$selector    = $rule->get_selector();
 75			$rules_group = $rule->get_rules_group();
 76
 77			/**
 78			 * If there is a rules_group and it already exists in the css_rules array,
 79			 * add the rule to it.
 80			 * Otherwise, create a new entry for the rules_group.
 81			 */
 82			if ( ! empty( $rules_group ) ) {
 83				if ( isset( $this->css_rules[ "$rules_group $selector" ] ) ) {
 84					$this->css_rules[ "$rules_group $selector" ]->add_declarations( $rule->get_declarations() );
 85					continue;
 86				}
 87				$this->css_rules[ "$rules_group $selector" ] = $rule;
 88				continue;
 89			}
 90
 91			// If the selector already exists, add the declarations to it.
 92			if ( isset( $this->css_rules[ $selector ] ) ) {
 93				$this->css_rules[ $selector ]->add_declarations( $rule->get_declarations() );
 94				continue;
 95			}
 96			$this->css_rules[ $rule->get_selector() ] = $rule;
 97		}
 98
 99		return $this;
100	}
101
102	/**
103	 * Gets the CSS rules as a string.
104	 *
105	 * @since 6.1.0
106	 * @since 6.4.0 The Optimization is no longer the default.
107	 *
108	 * @param array $options   {
109	 *     Optional. An array of options. Default empty array.
110	 *
111	 *     @type bool $optimize Whether to optimize the CSS output, e.g. combine rules.
112	 *                          Default false.
113	 *     @type bool $prettify Whether to add new lines and indents to output.
114	 *                          Defaults to whether the `SCRIPT_DEBUG` constant is defined.
115	 * }
116	 * @return string The computed CSS.
117	 */
118	public function get_css( $options = array() ) {
119		$defaults = array(
120			'optimize' => false,
121			'prettify' => defined( 'SCRIPT_DEBUG' ) && SCRIPT_DEBUG,
122		);
123		$options  = wp_parse_args( $options, $defaults );
124
125		// If we have stores, get the rules from them.
126		foreach ( $this->stores as $store ) {
127			$this->add_rules( $store->get_all_rules() );
128		}
129
130		// Combine CSS selectors that have identical declarations.
131		if ( true === $options['optimize'] ) {
132			$this->combine_rules_selectors();
133		}
134
135		// Build the CSS.
136		$css = '';
137		foreach ( $this->css_rules as $rule ) {
138			// See class WP_Style_Engine_CSS_Rule for the get_css method.
139			$css .= $rule->get_css( $options['prettify'] );
140			$css .= $options['prettify'] ? "\n" : '';
141		}
142		return $css;
143	}
144
145	/**
146	 * Combines selectors from the rules store when they have the same styles.
147	 *
148	 * @since 6.1.0
149	 */
150	private function combine_rules_selectors() {
151		// Build an array of selectors along with the JSON-ified styles to make comparisons easier.
152		$selectors_json = array();
153		foreach ( $this->css_rules as $rule ) {
154			$declarations = $rule->get_declarations()->get_declarations();
155			ksort( $declarations );
156			$selectors_json[ $rule->get_selector() ] = wp_json_encode( $declarations );
157		}
158
159		// Combine selectors that have the same styles.
160		foreach ( $selectors_json as $selector => $json ) {
161			// Get selectors that use the same styles.
162			$duplicates = array_keys( $selectors_json, $json, true );
163			// Skip if there are no duplicates.
164			if ( 1 >= count( $duplicates ) ) {
165				continue;
166			}
167
168			$declarations = $this->css_rules[ $selector ]->get_declarations();
169
170			foreach ( $duplicates as $key ) {
171				// Unset the duplicates from the $selectors_json array to avoid looping through them as well.
172				unset( $selectors_json[ $key ] );
173				// Remove the rules from the rules collection.
174				unset( $this->css_rules[ $key ] );
175			}
176			// Create a new rule with the combined selectors.
177			$duplicate_selectors                     = implode( ',', $duplicates );
178			$this->css_rules[ $duplicate_selectors ] = new WP_Style_Engine_CSS_Rule( $duplicate_selectors, $declarations );
179		}
180	}
181}
182