<?php
/**
 * Style engine: Public functions
 *
 * This file contains a variety of public functions developers can use to interact with
 * the Style Engine API.
 *
 * @package Gutenberg
 */

/**
 * Global public interface method to generate styles from a single style object, e.g.,
 * the value of a block's attributes.style object or the top level styles in theme.json.
 * See: https://developer.wordpress.org/block-editor/reference-guides/theme-json-reference/theme-json-living/#styles and
 * https://developer.wordpress.org/block-editor/reference-guides/block-api/block-supports/
 *
 * Example usage:
 *
 * $styles = gutenberg_style_engine_get_styles( array( 'color' => array( 'text' => '#cccccc' ) ) );
 * // Returns `array( 'css' => 'color: #cccccc', 'declarations' => array( 'color' => '#cccccc' ), 'classnames' => 'has-color' )`.
 *
 * @since 6.1.0
 *
 * @param array $block_styles The style object.
 * @param array $options {
 *     Optional. An array of options. Default empty array.
 *
 *     @type string|null $context                    An identifier describing the origin of the style object, e.g., 'block-supports' or 'global-styles'. Default is `null`.
 *                                                   When set, the Style Engine will attempt to store the CSS rules, where a selector is also passed.
 *     @type bool        $convert_vars_to_classnames Whether to skip converting incoming CSS var patterns, e.g., `var:preset|<PRESET_TYPE>|<PRESET_SLUG>`, to var( --wp--preset--* ) values. Default `false`.
 *     @type string      $selector                   Optional. When a selector is passed, the value of `$css` in the return value will comprise a full CSS rule `$selector { ...$css_declarations }`,
 *                                                   otherwise, the value will be a concatenated string of CSS declarations.
 * }
 *
 * @return array {
 *     @type string   $css          A CSS ruleset or declarations block formatted to be placed in an HTML `style` attribute or tag.
 *     @type string[] $declarations An associative array of CSS definitions, e.g., array( "$property" => "$value", "$property" => "$value" ).
 *     @type string   $classnames   Classnames separated by a space.
 * }
 */
function gutenberg_style_engine_get_styles( $block_styles, $options = array() ) {
	$options = wp_parse_args(
		$options,
		array(
			'selector'                   => null,
			'context'                    => null,
			'convert_vars_to_classnames' => false,
		)
	);

	$parsed_styles = WP_Style_Engine_Gutenberg::parse_block_styles( $block_styles, $options );

	// Output.
	$styles_output = array();

	if ( ! empty( $parsed_styles['declarations'] ) ) {
		$styles_output['css']          = WP_Style_Engine_Gutenberg::compile_css( $parsed_styles['declarations'], $options['selector'] );
		$styles_output['declarations'] = $parsed_styles['declarations'];
		if ( ! empty( $options['context'] ) ) {
			WP_Style_Engine_Gutenberg::store_css_rule( $options['context'], $options['selector'], $parsed_styles['declarations'] );
		}
	}

	if ( ! empty( $parsed_styles['classnames'] ) ) {
		$styles_output['classnames'] = implode( ' ', array_unique( $parsed_styles['classnames'] ) );
	}

	return array_filter( $styles_output );
}

/**
 * Returns compiled CSS from a collection of selectors and declarations.
 * Useful for returning a compiled stylesheet from any collection of  CSS selector + declarations.
 *
 * Example usage:
 * $css_rules = array( array( 'selector' => '.elephant-are-cool', 'declarations' => array( 'color' => 'gray', 'width' => '3em' ) ) );
 * $css       = gutenberg_style_engine_get_stylesheet_from_css_rules( $css_rules );
 * // Returns `.elephant-are-cool{color:gray;width:3em}`.
 *
 * @since 6.1.0
 *
 * @param array $css_rules {
 *     Required. A collection of CSS rules.
 *
 *     @type array ...$0 {
 *         @type string   $selector     A CSS selector.
 *         @type string[] $declarations An associative array of CSS definitions, e.g., array( "$property" => "$value", "$property" => "$value" ).
 *     }
 * }
 * @param array $options {
 *     Optional. An array of options. Default empty array.
 *
 *     @type string|null $context  An identifier describing the origin of the style object, e.g., 'block-supports' or 'global-styles'. Default is 'block-supports'.
 *                                 When set, the Style Engine will attempt to store the CSS rules.
 *     @type bool        $optimize Whether to optimize the CSS output, e.g., combine rules. Default is `false`.
 *     @type bool        $prettify Whether to add new lines and indents to output. Default is to inherit the value of the global constant `SCRIPT_DEBUG`, if it is defined.
 * }
 *
 * @return string A string of compiled CSS declarations, or empty string.
 */
function gutenberg_style_engine_get_stylesheet_from_css_rules( $css_rules, $options = array() ) {
	if ( empty( $css_rules ) ) {
		return '';
	}

	$options = wp_parse_args(
		$options,
		array(
			'context' => null,
		)
	);

	$css_rule_objects = array();
	foreach ( $css_rules as $css_rule ) {
		if ( empty( $css_rule['selector'] ) || empty( $css_rule['declarations'] ) || ! is_array( $css_rule['declarations'] ) ) {
			continue;
		}

		if ( ! empty( $options['context'] ) ) {
			WP_Style_Engine_Gutenberg::store_css_rule( $options['context'], $css_rule['selector'], $css_rule['declarations'] );
		}

		$css_rule_objects[] = new WP_Style_Engine_CSS_Rule_Gutenberg( $css_rule['selector'], $css_rule['declarations'] );
	}

	if ( empty( $css_rule_objects ) ) {
		return '';
	}

	return WP_Style_Engine_Gutenberg::compile_stylesheet_from_css_rules( $css_rule_objects, $options );
}

/**
 * Returns compiled CSS from a store, if found.
 *
 * @since 6.1.0
 *
 * @param string $context A valid context name, corresponding to an existing store key.
 * @param array  $options {
 *     Optional. An array of options. Default empty array.
 *
 *     @type bool $optimize Whether to optimize the CSS output, e.g., combine rules. Default is `false`.
 *     @type bool $prettify Whether to add new lines and indents to output. Default is to inherit the value of the global constant `SCRIPT_DEBUG`, if it is defined.
 * }
 *
 * @return string A compiled CSS string.
 */
function gutenberg_style_engine_get_stylesheet_from_context( $context, $options = array() ) {
	if ( empty( $context ) ) {
		return '';
	}

	return WP_Style_Engine_Gutenberg::compile_stylesheet_from_css_rules( WP_Style_Engine_Gutenberg::get_store( $context )->get_all_rules(), $options );
}
