<?php
/**
 * PHP and WordPress configuration compatibility functions for the Gutenberg
 * editor plugin.
 *
 * @package gutenberg
 */

if ( ! defined( 'ABSPATH' ) ) {
	die( 'Silence is golden.' );
}

/**
 * Splits a UTF-8 string into an array of UTF-8-encoded codepoints.
 *
 * @since 0.5.0
 *
 * Based on WordPress' _mb_substr() compat function.
 *
 * @param string $str        The string to split.
 * @return array
 */
function _gutenberg_utf8_split( $str ) {
	if ( _wp_can_use_pcre_u() ) {
		// Use the regex unicode support to separate the UTF-8 characters into
		// an array.
		preg_match_all( '/./us', $str, $match );
		return $match[0];
	}

	$regex = '/(
		  [\x00-\x7F]                  # single-byte sequences   0xxxxxxx
		| [\xC2-\xDF][\x80-\xBF]       # double-byte sequences   110xxxxx 10xxxxxx
		| \xE0[\xA0-\xBF][\x80-\xBF]   # triple-byte sequences   1110xxxx 10xxxxxx * 2
		| [\xE1-\xEC][\x80-\xBF]{2}
		| \xED[\x80-\x9F][\x80-\xBF]
		| [\xEE-\xEF][\x80-\xBF]{2}
		| \xF0[\x90-\xBF][\x80-\xBF]{2} # four-byte sequences   11110xxx 10xxxxxx * 3
		| [\xF1-\xF3][\x80-\xBF]{3}
		| \xF4[\x80-\x8F][\x80-\xBF]{2}
	)/x';

	// Start with 1 element instead of 0 since the first thing we do is pop.
	$chars = array( '' );
	do {
		// We had some string left over from the last round, but we counted it
		// in that last round.
		array_pop( $chars );

		// Split by UTF-8 character, limit to 1000 characters (last array
		// element will contain the rest of the string).
		$pieces = preg_split(
			$regex,
			$str,
			1000,
			PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY
		);

		$chars = array_merge( $chars, $pieces );

		// If there's anything left over, repeat the loop.
		if ( count( $pieces ) > 1 ) {
			$str = array_pop( $pieces );
		} else {
			break;
		}
	} while ( $str );

	return $chars;
}

/**
 * Disables wpautop behavior in classic editor when post contains blocks, to
 * prevent removep from invalidating paragraph blocks.
 *
 * @param  array  $settings  Original editor settings.
 * @param  string $editor_id ID for the editor instance.
 * @return array             Filtered settings.
 */
function gutenberg_disable_editor_settings_wpautop( $settings, $editor_id ) {
	$post = get_post();
	if ( 'content' === $editor_id && is_object( $post ) && has_blocks( $post ) ) {
		$settings['wpautop'] = false;
	}

	return $settings;
}
add_filter( 'wp_editor_settings', 'gutenberg_disable_editor_settings_wpautop', 10, 2 );

/**
 * Add rest nonce to the heartbeat response.
 *
 * @param  array $response Original heartbeat response.
 * @return array           New heartbeat response.
 */
function gutenberg_add_rest_nonce_to_heartbeat_response_headers( $response ) {
	$response['rest-nonce'] = wp_create_nonce( 'wp_rest' );
	return $response;
}
add_filter( 'wp_refresh_nonces', 'gutenberg_add_rest_nonce_to_heartbeat_response_headers' );

/**
 * Check if we need to load the block warning in the Classic Editor.
 *
 * @since 3.4.0
 */
function gutenberg_check_if_classic_needs_warning_about_blocks() {
	global $pagenow;

	if ( ! in_array( $pagenow, array( 'post.php', 'post-new.php' ), true ) || ! isset( $_REQUEST['classic-editor'] ) ) {
		return;
	}

	$post = get_post();
	if ( ! $post ) {
		return;
	}

	if ( ! has_blocks( $post ) ) {
		return;
	}

	// Enqueue the JS we're going to need in the dialog.
	wp_enqueue_script( 'wp-a11y' );
	wp_enqueue_script( 'wp-sanitize' );

	add_action( 'admin_footer', 'gutenberg_warn_classic_about_blocks' );
}
add_action( 'admin_enqueue_scripts', 'gutenberg_check_if_classic_needs_warning_about_blocks' );

/**
 * Adds a warning to the Classic Editor when trying to edit a post containing blocks.
 *
 * @since 3.4.0
 */
function gutenberg_warn_classic_about_blocks() {
	$post = get_post();

	$gutenberg_edit_link = get_edit_post_link( $post->ID, 'raw' );

	$classic_edit_link = $gutenberg_edit_link;
	$classic_edit_link = add_query_arg(
		array(
			'classic-editor'     => '',
			'hide-block-warning' => '',
		),
		$classic_edit_link
	);

	$revisions_link = '';
	if ( wp_revisions_enabled( $post ) ) {
		$revisions = wp_get_post_revisions( $post );

		// If there's only one revision, that won't help.
		if ( count( $revisions ) > 1 ) {
			reset( $revisions ); // Reset pointer for key().
			$revisions_link = get_edit_post_link( key( $revisions ) );
		}
	}
	?>
		<style type="text/css">
			#blocks-in-post-dialog .notification-dialog {
				position: fixed;
				top: 50%;
				left: 50%;
				width: 500px;
				box-sizing: border-box;
				transform: translate(-50%, -50%);
				margin: 0;
				padding: 25px;
				max-height: 90%;
				background: #fff;
				box-shadow: 0 3px 6px rgba(0, 0, 0, 0.3);
				line-height: 1.5;
				z-index: 1000005;
				overflow-y: auto;
			}

			@media only screen and (max-height: 480px), screen and (max-width: 450px) {
				#blocks-in-post-dialog .notification-dialog {
					top: 0;
					left: 0;
					width: 100%;
					height: 100%;
					transform: none;
					max-height: 100%;
				}
			}
		</style>

		<div id="blocks-in-post-dialog" class="notification-dialog-wrap">
			<div class="notification-dialog-background"></div>
			<div class="notification-dialog">
				<div class="blocks-in-post-message">
					<p><?php _e( 'This post was previously edited in Gutenberg. You can continue in the Classic Editor, but you may lose data and formatting.', 'gutenberg' ); ?></p>
					<?php
					if ( $revisions_link ) {
						?>
							<p>
							<?php
								/* translators: link to the post revisions page */
								printf( __( 'You can also <a href="%s">browse previous revisions</a> and restore a version of the post before it was edited in Gutenberg.', 'gutenberg' ), esc_url( $revisions_link ) );
							?>
							</p>
						<?php
					} else {
						?>
							<p><strong><?php _e( 'Because this post does not have revisions, you will not be able to revert any changes you make in the Classic Editor.', 'gutenberg' ); ?></strong></p>
						<?php
					}
					?>
				</div>
				<p>
					<a class="button button-primary blocks-in-post-gutenberg-button" href="<?php echo esc_url( $gutenberg_edit_link ); ?>"><?php _e( 'Edit in Gutenberg', 'gutenberg' ); ?></a>
					<button type="button" class="button blocks-in-post-classic-button"><?php _e( 'Continue to Classic Editor', 'gutenberg' ); ?></button>
				</p>
			</div>
		</div>

		<script type="text/javascript">
			/* <![CDATA[ */
			( function( $ ) {
				var dialog = {};

				dialog.init = function() {
					// The modal
					dialog.warning = $( '#blocks-in-post-dialog' );
					// Get the links and buttons within the modal.
					dialog.warningTabbables = dialog.warning.find( 'a, button' );

					// Get the text within the modal.
					dialog.rawMessage = dialog.warning.find( '.blocks-in-post-message' ).text();

					// Hide all the #wpwrap content from assistive technologies.
					$( '#wpwrap' ).attr( 'aria-hidden', 'true' );

					// Detach the warning modal from its position and append it to the body.
					$( document.body )
						.addClass( 'modal-open' )
						.append( dialog.warning.detach() );

					// Reveal the modal and set focus on the Gutenberg button.
					dialog.warning
						.removeClass( 'hidden' )
						.find( '.blocks-in-post-gutenberg-button' ).focus();

					// Attach event handlers.
					dialog.warningTabbables.on( 'keydown', dialog.constrainTabbing );
					dialog.warning.on( 'click', '.blocks-in-post-classic-button', dialog.dismissWarning );

					// Make screen readers announce the warning message after a short delay (necessary for some screen readers).
					setTimeout( function() {
						wp.a11y.speak( wp.sanitize.stripTags( dialog.rawMessage.replace( /\s+/g, ' ' ) ), 'assertive' );
					}, 1000 );
				};

				dialog.constrainTabbing = function( event ) {
					var firstTabbable, lastTabbable;

					if ( 9 !== event.which ) {
						return;
					}

					firstTabbable = dialog.warningTabbables.first()[0];
					lastTabbable = dialog.warningTabbables.last()[0];

					if ( lastTabbable === event.target && ! event.shiftKey ) {
						firstTabbable.focus();
						event.preventDefault();
					} else if ( firstTabbable === event.target && event.shiftKey ) {
						lastTabbable.focus();
						event.preventDefault();
					}
				};

				dialog.dismissWarning = function() {
					// Hide modal.
					dialog.warning.remove();
					$( '#wpwrap' ).removeAttr( 'aria-hidden' );
					$( 'body' ).removeClass( 'modal-open' );
				};

				$( document ).ready( dialog.init );
			} )( jQuery );
			/* ]]> */
		</script>
	<?php
}

/**
 * Display the privacy policy help notice.
 *
 * In Gutenberg, the `edit_form_after_title` hook is not supported. Because
 * WordPress Core uses this hook to display this notice, it never displays.
 * Outputting the notice on the `admin_notices` hook allows Gutenberg to
 * consume the notice and display it with the Notices API.
 *
 * @since 4.5.0
 */
function gutenberg_show_privacy_policy_help_text() {
	if ( is_gutenberg_page() && has_action( 'edit_form_after_title', array( 'WP_Privacy_Policy_Content', 'notice' ) ) ) {
		remove_action( 'edit_form_after_title', array( 'WP_Privacy_Policy_Content', 'notice' ) );

		WP_Privacy_Policy_Content::notice( get_post() );
	}
}
add_action( 'admin_notices', 'gutenberg_show_privacy_policy_help_text' );