<?php
/**
 * Handles the CSS Output of fields.
 *
 * @package     Kirki
 * @category    Modules
 * @author      Themeum
 * @copyright   Copyright (c) 2023, Themeum
 * @license    https://opensource.org/licenses/MIT
 * @since       3.0.0
 */

namespace Kirki\Module;

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

use Kirki\Compatibility\Kirki;
use Kirki\Util\Helper;
use Kirki\Compatibility\Values;
use Kirki\Module\CSS\Generator;

/**
 * The Module object.
 */
class CSS
{

	/**
	 * The class instance.
	 *
	 * @static
	 * @access private
	 * @since 1.0
	 * @var object
	 */
	private static $instance;

	/**
	 * The CSS array
	 *
	 * @access public
	 * @var array
	 */
	public static $css_array = array();

	/**
	 * An array of fields to be processed.
	 *
	 * @static
	 * @access protected
	 * @since 1.0
	 * @var array
	 */
	protected static $fields = array();

	/**
	 * Field option types.
	 *
	 * @static
	 * @access protected
	 * @since 1.0
	 * @var array
	 */
	protected static $field_option_types = array();

	/**
	 * The default handle for kirki's styles enqueue.
	 *
	 * @since 4.0
	 * @access private
	 * @static
	 *
	 * @var string
	 */
	private static $css_handle = 'kirki-styles';

	/**
	 * The default id for kirki's inline style tag.
	 *
	 * @since 4.0.23
	 * @access private
	 * @static
	 *
	 * @var string
	 */
	private static $inline_styles_id = 'kirki-inline-styles';

	/**
	 * Get the one, true instance of this class.
	 * Prevents performance issues since this is instantiated in a filter.
	 *
	 * @static
	 * @access public
	 * @since 1.0
	 * @return object
	 */
	public static function get_instance()
	{
		if (null === self::$instance) {
			self::$instance = new self();
		}
		return self::$instance;
	}

	/**
	 * Constructor
	 *
	 * @access public
	 */
	public function __construct()
	{

		add_action('kirki_field_init', array($this, 'field_init'), 10, 2);
		add_action('init', array($this, 'init'));

	}

	/**
	 * Init.
	 *
	 * @access public
	 */
	public function init()
	{

		new \Kirki\Module\Webfonts();

		add_action('wp', array($this, 'print_styles_action'));

		if (!apply_filters('kirki_output_inline_styles', true)) {
			$config = apply_filters('kirki_config', array());
			$priority = 999;

			if (isset($config['styles_priority'])) {
				$priority = absint($config['styles_priority']);
			}

		} else {
			add_action('wp_head', array($this, 'print_styles_inline'), 999);
		}

	}

	/**
	 * Runs when a field gets added.
	 * Adds fields to this object so their styles can later be generated.
	 *
	 * @access public
	 * @since 1.0
	 * @param array  $args   The field args.
	 * @param Object $object The field object.
	 * @return void
	 */
	public function field_init($args, $object)
	{

		if (!isset($args['output'])) {
			$args['output'] = array();
		}

		self::$field_option_types[$args['settings']] = isset($args['option_type']) ? $args['option_type'] : 'theme_mod';

		if (!is_array($args['output'])) {
			/* translators: The field ID where the error occurs. */
			_doing_it_wrong(__METHOD__, sprintf(esc_html__('"output" invalid format in field %s. The "output" argument should be defined as an array of arrays.', 'kirki'), esc_html($args['settings'])), '3.0.10');
			$args['output'] = array(
				array(
					'element' => $args['output'],
				),
			);
		}

		// Convert to array of arrays if needed.
		if (isset($args['output']['element'])) {
			/* translators: The field ID where the error occurs. */
			_doing_it_wrong(__METHOD__, sprintf(esc_html__('"output" invalid format in field %s. The "output" argument should be defined as an array of arrays.', 'kirki'), esc_html($args['settings'])), '3.0.10');
			$args['output'] = array($args['output']);
		}

		if (empty($args['output'])) {
			return;
		}

		foreach ($args['output'] as $key => $output) {
			if (empty($output) || !isset($output['element'])) {
				unset($args['output'][$key]);
				continue;
			}
			if (!isset($output['sanitize_callback']) && isset($output['callback'])) {
				$args['output'][$key]['sanitize_callback'] = $output['callback'];
			}

			// Convert element arrays to strings.
			if (isset($output['element']) && is_array($output['element'])) {
				$args['output'][$key]['element'] = array_unique($args['output'][$key]['element']);
				sort($args['output'][$key]['element']);

				// Trim each element in the array.
				foreach ($args['output'][$key]['element'] as $index => $element) {
					$args['output'][$key]['element'][$index] = trim($element);
				}
				$args['output'][$key]['element'] = implode(',', $args['output'][$key]['element']);
			}

			// Fix for https://github.com/aristath/kirki/issues/1659#issuecomment-346229751.
			$args['output'][$key]['element'] = str_replace(array("\t", "\n", "\r", "\0", "\x0B"), ' ', $args['output'][$key]['element']);
			$args['output'][$key]['element'] = trim(preg_replace('/\s+/', ' ', $args['output'][$key]['element']));
		}

		if (!isset($args['type']) && isset($object->type)) {
			$args['type'] = $object->type;
		}

		self::$fields[] = $args;

	}

	/**
	 * Print styles inline.
	 *
	 * @access public
	 * @since 3.0.36
	 * @return void
	 */
	public function print_styles_inline()
	{

		$should_print = true;

		if (defined('KIRKI_NO_OUTPUT') && true === KIRKI_NO_OUTPUT) {
			$should_print = false;
		}

		ob_start();
		$this->print_styles();
		$inline_styles = ob_get_clean();

		/**
		 * If KIRKI_NO_OUTPUT constant is defined (and is true), but typography field is defined, then print it.
		 * Otherwise, the typography field might be broken (missing font-family) if the font-face is not outputted.
		 */
		if (!$should_print && false !== stripos($inline_styles, '@font-face')) {
			$should_print = true;
		}

		if (!$should_print) {
			return;
		}

		$inline_styles_id = apply_filters('kirki_inline_styles_id', self::$inline_styles_id);

		echo '<style id="' . esc_attr($inline_styles_id) . '">';
		echo wp_strip_all_tags( $inline_styles ); // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped
		echo '</style>';

	}

	/**
	 * Enqueue the styles.
	 *
	 * @access public
	 * @since 3.0.36
	 * @return void
	 */
	public function enqueue_styles()
	{

		$args = array(
			'action' => apply_filters('kirki_styles_action_handle', self::$css_handle),
		);

		if (is_admin()) {
			global $current_screen;

			/**
			 * This `enqueue_styles` method is also hooked into `enqueue_block_editor_assets`.
			 * It needs to be excluded from customize control page.
			 *
			 * Why not simply excluding all admin area except gutenberg editing interface?
			 * Because it would be nice to let the possibility open
			 * if a 3rd party plugin will output gutenberg styles somewhere in admin area.
			 *
			 * Example of possibility:
			 * In the future, Ultimate Dashboard Pro's admin page feature might supports Gutenberg.
			 */
			if (is_object($current_screen) && property_exists($current_screen, 'id') && 'customize' === $current_screen->id) {
				return;
			}

			if (property_exists($current_screen, 'is_block_editor') && 1 === (int) $current_screen->is_block_editor) {
				$args['editor'] = '1';
			}
		}

		// Enqueue the dynamic stylesheet.
		wp_enqueue_style(
			self::$css_handle,
			add_query_arg( $args, home_url() ),
			array(),
			'4.0'
		);

	}

	/**
	 * Prints the styles as an enqueued file.
	 *
	 * @access public
	 * @since 3.0.36
	 * @return void
	 */
	public function print_styles_action()
	{

		/**
		 * Note to code reviewers:
		 * There is no need for a nonce check here, we're only checking if this is a valid request or not.
		 */

		// phpcs:ignore WordPress.Security.NonceVerification
		if (empty($_GET['action']) || apply_filters('kirki_styles_action_handle', self::$css_handle) !== $_GET['action']) {
			return;
		}

		// This is a stylesheet.
		header('Content-type: text/css');
		$this->print_styles();
		exit;

	}

	/**
	 * Prints the styles.
	 *
	 * @access public
	 */
	public function print_styles()
	{

		// Go through all configs.
		$configs = Kirki::$config;

		foreach ($configs as $config_id => $args) {
			if (defined('KIRKI_NO_OUTPUT') && true === KIRKI_NO_OUTPUT) {
				continue;
			}

			if (isset($args['disable_output']) && true === $args['disable_output']) {
				continue;
			}

			$styles = self::loop_controls($config_id);
			$styles = apply_filters("kirki_{$config_id}_dynamic_css", $styles);

			if (!empty($styles)) {
				/**
				 * Note to code reviewers:
				 *
				 * Though all output should be run through an escaping function, this is pure CSS.
				 *
				 * When used in the print_styles_action() method the PHP header() call makes the browser interpret it as such.
				 * No code, script or anything else can be executed from inside a stylesheet.
				 *
				 * When using in the print_styles_inline() method the wp_strip_all_tags call we use below
				 * strips anything that has the possibility to be malicious, and since this is inslide a <style> tag
				 * it can only be interpreted by the browser as such.
				 * wp_strip_all_tags() excludes the possibility of someone closing the <style> tag and then opening something else.
				 */
				echo wp_strip_all_tags($styles); // phpcs:ignore WordPress.Security.EscapeOutput
			}
		}

		do_action('kirki_dynamic_css');

	}

	/**
	 * Loop through all fields and create an array of style definitions.
	 *
	 * @static
	 * @access public
	 * @param string $config_id The configuration ID.
	 */
	public static function loop_controls($config_id)
	{

		// Get an instance of the Generator class.
		// This will make sure google fonts and backup fonts are loaded.
		Generator::get_instance();

		$fields = self::get_fields_by_config($config_id);

		// Compatibility with v3 API.
		if (class_exists('\Kirki\Compatibility\Kirki')) {
			$fields = array_merge(\Kirki\Compatibility\Kirki::$fields, $fields);
		}

		$css = array();

		// Early exit if no fields are found.
		if (empty($fields)) {
			return;
		}

		foreach ($fields as $field) {

			// Only process fields that belong to $config_id.
			if (isset($field['kirki_config']) && $config_id !== $field['kirki_config']) {
				continue;
			}

			if (true === apply_filters("kirki_{$config_id}_css_skip_hidden", true)) {

				// Only continue if field dependencies are met.
				if ((isset($field['required']) && !empty($field['required'])) || (isset($field['active_callback']) && !empty($field['active_callback']))) {
					$valid = true;

					// If $field is using active_callback instead of required.
					if (!isset($field['required']) || empty($field['required'])) {
						if (isset($field['active_callback']) && !empty($field['active_callback'])) {
							// The "active_callback" or "required" accepts array or callable as the value.
							if (is_array($field['active_callback']) || is_callable($field['active_callback'])) {
								$field['required'] = $field['active_callback'];
							}
						}
					}

					// At this point, we know that the "required" is set and is not empty.
					if (is_array($field['required'])) {
						foreach ($field['required'] as $requirement) {
							if (isset($requirement['setting']) && isset($requirement['value']) && isset($requirement['operator']) && isset(self::$field_option_types[$requirement['setting']])) {
								$controller_value = Values::get_value($config_id, $requirement['setting']);

								if (!Helper::compare_values($controller_value, $requirement['value'], $requirement['operator'])) {
									$valid = false;
								}
							}
						}
					} elseif (is_string($field['required'])) {
						$valid = '__return_true' === $field['required'] ? true : false;
					} elseif (is_callable($field['required'])) {
						$valid = call_user_func($field['required']);
					}

					if (!$valid) {
						continue;
					}
				}
			}

			// Only continue if $field['output'] is set.
			if (isset($field['output']) && !empty($field['output'])) {
				$css = Helper::array_replace_recursive($css, Generator::css($field));

				// Add the globals.
				if (isset(self::$css_array[$config_id]) && !empty(self::$css_array[$config_id])) {
					Helper::array_replace_recursive($css, self::$css_array[$config_id]);
				}
			}
		}

		$css = apply_filters("kirki_{$config_id}_styles", $css);

		if (is_array($css)) {
			return Generator::styles_parse(Generator::add_prefixes($css));
		}

	}

	/**
	 * Gets fields from self::$fields by config-id.
	 *
	 * @static
	 * @access private
	 * @since 1.0
	 * @param string $config_id The config-ID.
	 * @return array
	 */
	private static function get_fields_by_config($config_id)
	{

		$fields = array();

		foreach (self::$fields as $field) {
			if (
				(isset($field['kirki_config']) && $config_id === $field['kirki_config']) ||
				(
					('global' === $config_id || !$config_id) &&
					(!isset($field['kirki_config']) || 'global' === $field['kirki_config'] || !$field['kirki_config'])
				)
			) {
				$fields[] = $field;
			}
		}

		return $fields;

	}

}