<?php
/**
 * MailChimp Subscriber Popup Form shortcode
 *
 * Example:
 * [mailchimp_subscriber_popup baseUrl="mc.us11.list-manage.com" uuid="1ca7856462585a934b8674c71" lid="2d24f1898b"]
 *
 * Embed code example:
 * <script type="text/javascript" src="//downloads.mailchimp.com/js/signup-forms/popup/embed.js" data-dojo-config="usePlainJson: true, isDebug: false"></script><script type="text/javascript">require(["mojo/signup-forms/Loader"], function(L) { L.start({"baseUrl":"mc.us11.list-manage.com","uuid":"1ca7856462585a934b8674c71","lid":"2d24f1898b"}) })</script>
 *
 */

/**
 * Register [mailchimp_subscriber_popup] shortcode and add a filter to 'pre_kses' queue to reverse MailChimp embed to shortcode.
 *
 * @since 4.5.0
 */
function jetpack_mailchimp_subscriber_popup() {
	add_shortcode( 'mailchimp_subscriber_popup', array(
		'MailChimp_Subscriber_Popup',
		'shortcode'
	) );
	add_filter( 'pre_kses', array(
		'MailChimp_Subscriber_Popup',
		'reversal'
	) );
}

if ( defined( 'IS_WPCOM' ) && IS_WPCOM ) {
	add_action( 'init', 'jetpack_mailchimp_subscriber_popup' );
} else {
	jetpack_mailchimp_subscriber_popup();
}

/**
 * Class MailChimp_Subscriber_Popup
 *
 * @since 4.5.0
 */
class MailChimp_Subscriber_Popup {

	/**
	 * Regular expressions to reverse script tags to shortcodes.
	 *
	 * @var array
	 */
	static $reversal_regexes = array(
		/* raw examplejs */
		'/<script type="text\/javascript" src="(https?:)?\/\/downloads\.mailchimp\.com\/js\/signup-forms\/popup\/embed\.js" data-dojo-config="([^"]*?)"><\/script><script type="text\/javascript">require\(\["mojo\/signup-forms\/Loader"\]\, function\(L\) { L\.start\({([^}]*?)}\) }\)<\/script>/s',
		/* visual editor */
		'/&lt;script type="text\/javascript" src="(https?:)?\/\/downloads\.mailchimp\.com\/js\/signup-forms\/popup\/embed\.js" data-dojo-config="([^"]*?)"&gt;&lt;\/script&gt;&lt;script type="text\/javascript"&gt;require\(\["mojo\/signup-forms\/Loader"]\, function\(L\) { L\.start\({([^}]*?)}\) }\)&lt;\/script&gt;/s',
	);

	/**
	 * Allowed configuration attributes. Used in reversal when checking allowed attributes.
	 *
	 * @var array
	 */
	static $allowed_config = array(
		'usePlainJson' => 'true',
		'isDebug'      => 'false',
	);

	/**
	 * Allowed JS variables. Used in reversal to whitelist variables.
	 *
	 * @var array
	 */
	static $allowed_js_vars = array(
		'baseUrl',
		'uuid',
		'lid',
	);

	/**
	 * Runs the whole reversal.
	 *
	 * @since 4.5.0
	 *
	 * @param string $content Post Content
	 *
	 * @return string Content with embeds replaced
	 */
	static function reversal( $content ) {
		// Bail without the js src
		if ( ! is_string( $content ) || false === stripos( $content, 'downloads.mailchimp.com/js/signup-forms/popup/embed.js' ) ) {
			return $content;
		}

		require_once( ABSPATH . WPINC . '/class-json.php' );
		$wp_json = new Services_JSON();

		// loop through our rules and find valid embeds
		foreach ( self::$reversal_regexes as $regex ) {

			if ( ! preg_match_all( $regex, $content, $matches ) ) {
				continue;
			}

			foreach ( $matches[3] as $index => $js_vars ) {
				// the regex rule for a specific embed
				$replace_regex = sprintf( '#\s*%s\s*#', preg_quote( $matches[0][$index], '#' ) );

				$attrs = $wp_json->decode( '{' . $js_vars . '}' );

				if ( $matches[2][$index] ) {
					$config_attrs = $wp_json->decode( '{' . $matches[2][$index] . '}' );
					foreach ( $config_attrs as $key => $value ) {
						$attrs->$key = ( 1 == $value ) ? 'true' : 'false';
					}
				}

				$shortcode = self::build_shortcode_from_reversal_attrs( $attrs );

				$content = preg_replace( $replace_regex, "\n\n$shortcode\n\n", $content );

				/** This action is documented in modules/widgets/social-media-icons.php */
				do_action( 'jetpack_bump_stats_extras', 'html_to_shortcode', 'mailchimp_subscriber_popup' );
			}
		}

		return $content;
	}

	/**
	 * Builds the actual shortcode based on passed in attributes.
	 *
	 * @since 4.5.0
	 *
	 * @param array $attrs A valid list of attributes (gets matched against self::$allowed_config and self::$allowed_js_vars)
	 *
	 * @return string
	 */
	static function build_shortcode_from_reversal_attrs( $attrs ) {
		$shortcode = '[mailchimp_subscriber_popup ';

		foreach ( $attrs as $key => $value ) {
			// skip unsupported keys
			if ( ! in_array( $key, array_keys( self::$allowed_config ) ) && ! in_array( $key, self::$allowed_js_vars ) ) {
				continue;
			}

			$value      = esc_attr( $value );
			$shortcode .= "$key='$value' ";
		}
		return trim( $shortcode ) . ']';
	}

	/**
	 * Parses the shortcode back out to embedded information.
	 *
	 * @since 4.5.0
	 *
	 * @param array $lcase_attrs
	 *
	 * @return string
	 */
	static function shortcode( $lcase_attrs ) {
		static $displayed_once = false;

		// Limit to one form per page load
		if ( $displayed_once ) {
			return '';
		}

		if ( empty( $lcase_attrs ) ) {
			return '<!-- Missing MailChimp baseUrl, uuid or lid -->';
		}

		$defaults = array_fill_keys( self::$allowed_js_vars, '' );
		$defaults = array_merge( $defaults, self::$allowed_config );

		// Convert $attrs back to proper casing since they come through in all lowercase
		$attrs = array();
		foreach ( $defaults as $key => $value ) {
			if ( array_key_exists( strtolower( $key ), $lcase_attrs ) ) {
				$attrs[ $key ] = $lcase_attrs[ strtolower( $key ) ];
			}
		}
		$attrs = array_map( 'esc_js', array_filter( shortcode_atts( $defaults, $attrs ) ) );

		// Split config & js vars
		$config_vars = $js_vars = array();
		foreach ( $attrs as $key => $value ) {
			if ( in_array( $key, self::$allowed_js_vars ) ) {
				$js_vars[ $key ] = $value;
			} else {
				$config_vars[] = "$key: $value";
			}
		}

		// If one of these parameters is missing we can't render the form so exist.
		if ( empty( $js_vars['baseUrl'] ) || empty( $js_vars['uuid'] ) || empty( $js_vars['lid'] ) ) {
			return '<!-- Missing MailChimp baseUrl, uuid or lid -->';
		}

		/** This action is already documented in modules/widgets/gravatar-profile.php */
		do_action( 'jetpack_stats_extra', 'mailchimp_subscriber_popup', 'view' );

		$displayed_once = true;

		return "\n\n" . '<script type="text/javascript" data-dojo-config="' . esc_attr( implode( ', ', $config_vars ) ) . '">jQuery.getScript( "//downloads.mailchimp.com/js/signup-forms/popup/embed.js", function( data, textStatus, jqxhr ) { require(["mojo/signup-forms/Loader"], function(L) { L.start(' . wp_json_encode( $js_vars ) . ') }); window.define.amd = undefined; } );</script>' . "\n\n";
	}
}
