<?php

/**

 * WordPress Administration Revisions API

 *

 * @package WordPress

 * @subpackage Administration

 * @since 3.6.0

 */

/**

 * Get the revision UI diff.

 *

 * @since 3.6.0

 *

 * @param WP_Post|int $post         The post object or post ID.

 * @param int         $compare_from The revision ID to compare from.

 * @param int         $compare_to   The revision ID to come to.

 * @return array|false Associative array of a post's revisioned fields and their diffs.

 *                     Or, false on failure.

 */

function wp_get_revision_ui_diff( $post, $compare_from, $compare_to ) {

	$post = get_post( $post );

	if ( ! $post ) {

		return false;

	}

	if ( $compare_from ) {

		$compare_from = get_post( $compare_from );

		if ( ! $compare_from ) {

			return false;

		}

	} else {

		// If we're dealing with the first revision...

		$compare_from = false;

	}

	$compare_to = get_post( $compare_to );

	if ( ! $compare_to ) {

		return false;

	}

	/*

	 * If comparing revisions, make sure we are dealing with the right post parent.

	 * The parent post may be a 'revision' when revisions are disabled and we're looking at autosaves.

	 */

	if ( $compare_from && $compare_from->post_parent !== $post->ID && $compare_from->ID !== $post->ID ) {

		return false;

	}

	if ( $compare_to->post_parent !== $post->ID && $compare_to->ID !== $post->ID ) {

		return false;

	}

	if ( $compare_from && strtotime( $compare_from->post_date_gmt ) > strtotime( $compare_to->post_date_gmt ) ) {

		$temp         = $compare_from;

		$compare_from = $compare_to;

		$compare_to   = $temp;

	}

	// Add default title if title field is empty.

	if ( $compare_from && empty( $compare_from->post_title ) ) {

		$compare_from->post_title = __( '(no title)' );

	}

	if ( empty( $compare_to->post_title ) ) {

		$compare_to->post_title = __( '(no title)' );

	}

	$return = array();

	foreach ( _wp_post_revision_fields( $post ) as $field => $name ) {

		/**

		 * Contextually filter a post revision field.

		 *

		 * The dynamic portion of the hook name, `$field`, corresponds to a name of a

		 * field of the revision object.

		 *

		 * Possible hook names include:

		 *

		 *  - `_wp_post_revision_field_post_title`

		 *  - `_wp_post_revision_field_post_content`

		 *  - `_wp_post_revision_field_post_excerpt`

		 *

		 * @since 3.6.0

		 *

		 * @param string  $revision_field The current revision field to compare to or from.

		 * @param string  $field          The current revision field.

		 * @param WP_Post $compare_from   The revision post object to compare to or from.

		 * @param string  $context        The context of whether the current revision is the old

		 *                                or the new one. Either 'to' or 'from'.

		 */

		$content_from = $compare_from ? apply_filters( "_wp_post_revision_field_{$field}", $compare_from->$field, $field, $compare_from, 'from' ) : '';

		/** This filter is documented in wp-admin/includes/revision.php */

		$content_to = apply_filters( "_wp_post_revision_field_{$field}", $compare_to->$field, $field, $compare_to, 'to' );

		$args = array(

			'show_split_view' => true,

			'title_left'      => __( 'Removed' ),

			'title_right'     => __( 'Added' ),

		);

		/**

		 * Filters revisions text diff options.

		 *

		 * Filters the options passed to wp_text_diff() when viewing a post revision.

		 *

		 * @since 4.1.0

		 *

		 * @param array   $args {

		 *     Associative array of options to pass to wp_text_diff().

		 *

		 *     @type bool $show_split_view True for split view (two columns), false for

		 *                                 un-split view (single column). Default true.

		 * }

		 * @param string  $field        The current revision field.

		 * @param WP_Post $compare_from The revision post to compare from.

		 * @param WP_Post $compare_to   The revision post to compare to.

		 */

		$args = apply_filters( 'revision_text_diff_options', $args, $field, $compare_from, $compare_to );

		$diff = wp_text_diff( $content_from, $content_to, $args );

		if ( ! $diff && 'post_title' === $field ) {

			/*

			 * It's a better user experience to still show the Title, even if it didn't change.

			 * No, you didn't see this.

			 */

			$diff = '<table class="diff"><colgroup><col class="content diffsplit left"><col class="content diffsplit middle"><col class="content diffsplit right"></colgroup><tbody><tr>';

			// In split screen mode, show the title before/after side by side.

			if ( true === $args['show_split_view'] ) {

				$diff .= '<td>' . esc_html( $compare_from->post_title ) . '</td><td></td><td>' . esc_html( $compare_to->post_title ) . '</td>';

			} else {

				$diff .= '<td>' . esc_html( $compare_from->post_title ) . '</td>';

				// In single column mode, only show the title once if unchanged.

				if ( $compare_from->post_title !== $compare_to->post_title ) {

					$diff .= '</tr><tr><td>' . esc_html( $compare_to->post_title ) . '</td>';

				}

			}

			$diff .= '</tr></tbody>';

			$diff .= '</table>';

		}

		if ( $diff ) {

			$return[] = array(

				'id'   => $field,

				'name' => $name,

				'diff' => $diff,

			);

		}

	}

	/**

	 * Filters the fields displayed in the post revision diff UI.

	 *

	 * @since 4.1.0

	 *

	 * @param array[] $return       Array of revision UI fields. Each item is an array of id, name, and diff.

	 * @param WP_Post $compare_from The revision post to compare from.

	 * @param WP_Post $compare_to   The revision post to compare to.

	 */

	return apply_filters( 'wp_get_revision_ui_diff', $return, $compare_from, $compare_to );

}

/**

 * Prepare revisions for JavaScript.

 *

 * @since 3.6.0

 *

 * @param WP_Post|int $post                 The post object or post ID.

 * @param int         $selected_revision_id The selected revision ID.

 * @param int         $from                 Optional. The revision ID to compare from.

 * @return array An associative array of revision data and related settings.

 */

function wp_prepare_revisions_for_js( $post, $selected_revision_id, $from = null ) {

	$post    = get_post( $post );

	$authors = array();

	$now_gmt = time();

	$revisions = wp_get_post_revisions(

		$post->ID,

		array(

			'order'         => 'ASC',

			'check_enabled' => false,

		)

	);

	// If revisions are disabled, we only want autosaves and the current post.

	if ( ! wp_revisions_enabled( $post ) ) {

		foreach ( $revisions as $revision_id => $revision ) {

			if ( ! wp_is_post_autosave( $revision ) ) {

				unset( $revisions[ $revision_id ] );

			}

		}

		$revisions = array( $post->ID => $post ) + $revisions;

	}

	$show_avatars = get_option( 'show_avatars' );

	update_post_author_caches( $revisions );

	$can_restore = current_user_can( 'edit_post', $post->ID );

	$current_id  = false;

	foreach ( $revisions as $revision ) {

		$modified     = strtotime( $revision->post_modified );

		$modified_gmt = strtotime( $revision->post_modified_gmt . ' +0000' );

		if ( $can_restore ) {

			$restore_link = str_replace(

				'&',

				'&',

				wp_nonce_url(

					add_query_arg(

						array(

							'revision' => $revision->ID,

							'action'   => 'restore',

						),

						admin_url( 'revision.php' )

					),

					"restore-post_{$revision->ID}"

				)

			);

		}

		if ( ! isset( $authors[ $revision->post_author ] ) ) {

			$authors[ $revision->post_author ] = array(

				'id'     => (int) $revision->post_author,

				'avatar' => $show_avatars ? get_avatar( $revision->post_author, 32 ) : '',

				'name'   => get_the_author_meta( 'display_name', $revision->post_author ),

			);

		}

		$autosave = (bool) wp_is_post_autosave( $revision );

		$current  = ! $autosave && $revision->post_modified_gmt === $post->post_modified_gmt;

		if ( $current && ! empty( $current_id ) ) {

			// If multiple revisions have the same post_modified_gmt, highest ID is current.

			if ( $current_id < $revision->ID ) {

				$revisions[ $current_id ]['current'] = false;

				$current_id                          = $revision->ID;

			} else {

				$current = false;

			}

		} elseif ( $current ) {

			$current_id = $revision->ID;

		}

		$revisions_data = array(

			'id'         => $revision->ID,

			'title'      => get_the_title( $post->ID ),

			'author'     => $authors[ $revision->post_author ],

			'date'       => date_i18n( __( 'M j, Y @ H:i' ), $modified ),

			'dateShort'  => date_i18n( _x( 'j M @ H:i', 'revision date short format' ), $modified ),

			/* translators: %s: Human-readable time difference. */

			'timeAgo'    => sprintf( __( '%s ago' ), human_time_diff( $modified_gmt, $now_gmt ) ),

			'autosave'   => $autosave,

			'current'    => $current,

			'restoreUrl' => $can_restore ? $restore_link : false,

		);

		/**

		 * Filters the array of revisions used on the revisions screen.

		 *

		 * @since 4.4.0

		 *

		 * @param array   $revisions_data {

		 *     The bootstrapped data for the revisions screen.

		 *

		 *     @type int        $id         Revision ID.

		 *     @type string     $title      Title for the revision's parent WP_Post object.

		 *     @type int        $author     Revision post author ID.

		 *     @type string     $date       Date the revision was modified.

		 *     @type string     $dateShort  Short-form version of the date the revision was modified.

		 *     @type string     $timeAgo    GMT-aware amount of time ago the revision was modified.

		 *     @type bool       $autosave   Whether the revision is an autosave.

		 *     @type bool       $current    Whether the revision is both not an autosave and the post

		 *                                  modified date matches the revision modified date (GMT-aware).

		 *     @type bool|false $restoreUrl URL if the revision can be restored, false otherwise.

		 * }

		 * @param WP_Post $revision       The revision's WP_Post object.

		 * @param WP_Post $post           The revision's parent WP_Post object.

		 */

		$revisions[ $revision->ID ] = apply_filters( 'wp_prepare_revision_for_js', $revisions_data, $revision, $post );

	}

	/*

	 * If we only have one revision, the initial revision is missing. This happens

	 * when we have an autosave and the user has clicked 'View the Autosave'.

	 */

	if ( 1 === count( $revisions ) ) {

		$revisions[ $post->ID ] = array(

			'id'         => $post->ID,

			'title'      => get_the_title( $post->ID ),

			'author'     => $authors[ $revision->post_author ],

			'date'       => date_i18n( __( 'M j, Y @ H:i' ), strtotime( $post->post_modified ) ),

			'dateShort'  => date_i18n( _x( 'j M @ H:i', 'revision date short format' ), strtotime( $post->post_modified ) ),

			/* translators: %s: Human-readable time difference. */

			'timeAgo'    => sprintf( __( '%s ago' ), human_time_diff( strtotime( $post->post_modified_gmt ), $now_gmt ) ),

			'autosave'   => false,

			'current'    => true,

			'restoreUrl' => false,

		);

		$current_id             = $post->ID;

	}

	/*

	 * If a post has been saved since the latest revision (no revisioned fields

	 * were changed), we may not have a "current" revision. Mark the latest

	 * revision as "current".

	 */

	if ( empty( $current_id ) ) {

		if ( $revisions[ $revision->ID ]['autosave'] ) {

			$revision = end( $revisions );

			while ( $revision['autosave'] ) {

				$revision = prev( $revisions );

			}

			$current_id = $revision['id'];

		} else {

			$current_id = $revision->ID;

		}

		$revisions[ $current_id ]['current'] = true;

	}

	// Now, grab the initial diff.

	$compare_two_mode = is_numeric( $from );

	if ( ! $compare_two_mode ) {

		$found = array_search( $selected_revision_id, array_keys( $revisions ), true );

		if ( $found ) {

			$from = array_keys( array_slice( $revisions, $found - 1, 1, true ) );

			$from = reset( $from );

		} else {

			$from = 0;

		}

	}

	$from = absint( $from );

	$diffs = array(

		array(

			'id'     => $from . ':' . $selected_revision_id,

			'fields' => wp_get_revision_ui_diff( $post->ID, $from, $selected_revision_id ),

		),

	);

	return array(

		'postId'         => $post->ID,

		'nonce'          => wp_create_nonce( 'revisions-ajax-nonce' ),

		'revisionData'   => array_values( $revisions ),

		'to'             => $selected_revision_id,

		'from'           => $from,

		'diffData'       => $diffs,

		'baseUrl'        => parse_url( admin_url( 'revision.php' ), PHP_URL_PATH ),

		'compareTwoMode' => absint( $compare_two_mode ), // Apparently booleans are not allowed.

		'revisionIds'    => array_keys( $revisions ),

	);

}

/**

 * Print JavaScript templates required for the revisions experience.

 *

 * @since 4.1.0

 *

 * @global WP_Post $post Global post object.

 */

function wp_print_revision_templates() {

	global $post;

	?><script id="tmpl-revisions-frame" type="text/html">

		<div class="revisions-control-frame"></div>

		<div class="revisions-diff-frame"></div>

	</script>

	<script id="tmpl-revisions-buttons" type="text/html">

		<div class="revisions-previous">

			<input class="button" type="button" value="<?php echo esc_attr_x( 'Previous', 'Button label for a previous revision' ); ?>" />

		</div>

		<div class="revisions-next">

			<input class="button" type="button" value="<?php echo esc_attr_x( 'Next', 'Button label for a next revision' ); ?>" />

		</div>

	</script>

	<script id="tmpl-revisions-checkbox" type="text/html">

		<div class="revision-toggle-compare-mode">

			<label>

				<input type="checkbox" class="compare-two-revisions"

				<#

				if ( 'undefined' !== typeof data && data.model.attributes.compareTwoMode ) {

					#> checked="checked"<#

				}

				#>

				/>

				<?php esc_html_e( 'Compare any two revisions' ); ?>

			</label>

		</div>

	</script>

	<script id="tmpl-revisions-meta" type="text/html">

		<# if ( ! _.isUndefined( data.attributes ) ) { #>

			<div class="diff-title">

				<# if ( 'from' === data.type ) { #>

				<# } else if ( 'to' === data.type ) { #>