<?php

if ( ! defined( 'ABSPATH' ) ) {
	exit; // Exit if accessed directly
}

if ( ! class_exists( 'acf_revisions' ) ) :

	class acf_revisions {

		// vars
		var $cache = array();


		/*
		*  __construct
		*
		*  A good place to add actions / filters
		*
		*  @type    function
		*  @date    11/08/13
		*
		*  @param   N/A
		*  @return  N/A
		*/

		function __construct() {

			// actions
			add_action( 'wp_restore_post_revision', array( $this, 'wp_restore_post_revision' ), 10, 2 );

			// filters
			add_filter( 'wp_save_post_revision_check_for_changes', array( $this, 'wp_save_post_revision_check_for_changes' ), 10, 3 );
			add_filter( '_wp_post_revision_fields', array( $this, 'wp_preview_post_fields' ), 10, 2 );
			add_filter( '_wp_post_revision_fields', array( $this, 'wp_post_revision_fields' ), 10, 2 );
			add_filter( 'acf/validate_post_id', array( $this, 'acf_validate_post_id' ), 10, 2 );

		}


		/*
		*  wp_preview_post_fields
		*
		*  This function is used to trick WP into thinking that one of the $post's fields has changed and
		*  will allow an autosave to be updated.
		*  Fixes an odd bug causing the preview page to render the non autosave post data on every odd attempt
		*
		*  @type    function
		*  @date    21/10/2014
		*  @since   5.1.0
		*
		*  @param   $fields (array)
		*  @return  $fields
		*/

		function wp_preview_post_fields( $fields ) {

			// bail early if not previewing a post
			if ( acf_maybe_get_POST( 'wp-preview' ) !== 'dopreview' ) {
				return $fields;
			}

			// add to fields if ACF has changed
			if ( acf_maybe_get_POST( '_acf_changed' ) ) {

				$fields['_acf_changed'] = 'different than 1';

			}

			// return
			return $fields;

		}


		/*
		*  wp_save_post_revision_check_for_changes
		*
		*  This filter will return false and force WP to save a revision. This is required due to
		*  WP checking only post_title, post_excerpt and post_content values, not custom fields.
		*
		*  @type    filter
		*  @date    19/09/13
		*
		*  @param   $return (boolean) defaults to true
		*  @param   $last_revision (object) the last revision that WP will compare against
		*  @param   $post (object) the $post that WP will compare against
		*  @return  $return (boolean)
		*/

		function wp_save_post_revision_check_for_changes( $return, $last_revision, $post ) {

			// if acf has changed, return false and prevent WP from performing 'compare' logic
			if ( acf_maybe_get_POST( '_acf_changed' ) ) {
				return false;
			}

			// return
			return $return;

		}


		/*
		*  wp_post_revision_fields
		*
		*  This filter will add the ACF fields to the returned array
		*  Versions 3.5 and 3.6 of WP feature different uses of the revisions filters, so there are
		*  some hacks to allow both versions to work correctly
		*
		*  @type    filter
		*  @date    11/08/13
		*
		*  @param   $post_id (int)
		*  @return  $post_id (int)
		*/

		function wp_post_revision_fields( $fields, $post = null ) {

			// validate page
			if ( acf_is_screen( 'revision' ) || acf_is_ajax( 'get-revision-diffs' ) ) {

				// bail early if is restoring
				if ( acf_maybe_get_GET( 'action' ) === 'restore' ) {
					return $fields;
				}

				// allow

			} else {

				// bail early (most likely saving a post)
				return $fields;

			}

			// vars
			$append  = array();
			$order   = array();
			$post_id = acf_maybe_get( $post, 'ID' );

			// compatibility with WP < 4.5 (test)
			if ( ! $post_id ) {

				global $post;
				$post_id = $post->ID;

			}

			// get all postmeta
			$meta = get_post_meta( $post_id );

			// bail early if no meta
			if ( ! $meta ) {
				return $fields;
			}

			// loop
			foreach ( $meta as $name => $value ) {

				// attempt to find key value
				$key = acf_maybe_get( $meta, '_' . $name );

				// bail ealry if no key
				if ( ! $key ) {
					continue;
				}

				// update vars
				$value = $value[0];
				$key   = $key[0];

				// Load field.
				$field = acf_get_field( $key );
				if ( ! $field ) {
					continue;
				}

				// get field
				$field_title = $field['label'] . ' (' . $name . ')';
				$field_order = $field['menu_order'];
				$ancestors   = acf_get_field_ancestors( $field );

				// ancestors
				if ( ! empty( $ancestors ) ) {

					// vars
					$count  = count( $ancestors );
					$oldest = acf_get_field( $ancestors[ $count - 1 ] );

					// update vars
					$field_title = str_repeat( '- ', $count ) . $field_title;
					$field_order = $oldest['menu_order'] . '.1';

				}

				// append
				$append[ $name ] = $field_title;
				$order[ $name ]  = $field_order;

				// hook into specific revision field filter and return local value
				add_filter( "_wp_post_revision_field_{$name}", array( $this, 'wp_post_revision_field' ), 10, 4 );

			}

			// append
			if ( ! empty( $append ) ) {

				// vars
				$prefix = '_';

				// add prefix
				$append = acf_add_array_key_prefix( $append, $prefix );
				$order  = acf_add_array_key_prefix( $order, $prefix );

				// sort by name (orders sub field values correctly)
				array_multisort( $order, $append );

				// remove prefix
				$append = acf_remove_array_key_prefix( $append, $prefix );

				// append
				$fields = $fields + $append;

			}

			// return
			return $fields;

		}


		/*
		*  wp_post_revision_field
		*
		*  This filter will load the value for the given field and return it for rendering
		*
		*  @type    filter
		*  @date    11/08/13
		*
		*  @param   $value (mixed) should be false as it has not yet been loaded
		*  @param   $field_name (string) The name of the field
		*  @param   $post (mixed) Holds the $post object to load from - in WP 3.5, this is not passed!
		*  @param   $direction (string) to / from - not used
		*  @return  $value (string)
		*/

		function wp_post_revision_field( $value, $field_name, $post = null, $direction = false ) {

			// bail ealry if is empty
			if ( empty( $value ) ) {
				return $value;
			}

			// value has not yet been 'maybe_unserialize'
			$value = maybe_unserialize( $value );

			// vars
			$post_id = $post->ID;

			// load field
			$field = acf_maybe_get_field( $field_name, $post_id );

			// default formatting
			if ( is_array( $value ) ) {

				$value = implode( ', ', $value );

			} elseif ( is_object( $value ) ) {

				$value = serialize( $value );

			}

			// image
			if ( $field['type'] == 'image' || $field['type'] == 'file' ) {

				$url   = wp_get_attachment_url( $value );
				$value = $value . ' (' . $url . ')';

			}

			// return
			return $value;

		}


		/*
		*  wp_restore_post_revision
		*
		*  This action will copy and paste the metadata from a revision to the post
		*
		*  @type    action
		*  @date    11/08/13
		*
		*  @param   $parent_id (int) the destination post
		*  @return  $revision_id (int) the source post
		*/

		function wp_restore_post_revision( $post_id, $revision_id ) {

			// copy postmeta from revision to post (restore from revision)
			acf_copy_postmeta( $revision_id, $post_id );

			// Make sure the latest revision is also updated to match the new $post data
			// get latest revision
			$revision = acf_get_post_latest_revision( $post_id );

			// save
			if ( $revision ) {

				// copy postmeta from revision to latest revision (potentialy may be the same, but most likely are different)
				acf_copy_postmeta( $revision_id, $revision->ID );

			}

		}


		/*
		*  acf_validate_post_id
		*
		*  This function will modify the $post_id and allow loading values from a revision
		*
		*  @type    function
		*  @date    6/3/17
		*  @since   5.5.10
		*
		*  @param   $post_id (int)
		*  @param   $_post_id (int)
		*  @return  $post_id (int)
		*/

		function acf_validate_post_id( $post_id, $_post_id ) {

			// bail early if no preview in URL
			if ( ! isset( $_GET['preview'] ) ) {
				return $post_id;
			}

			// bail early if $post_id is not numeric
			if ( ! is_numeric( $post_id ) ) {
				return $post_id;
			}

			// vars
			$k          = $post_id;
			$preview_id = 0;

			// check cache
			if ( isset( $this->cache[ $k ] ) ) {
				return $this->cache[ $k ];
			}

			// validate
			if ( isset( $_GET['preview_id'] ) ) {

				$preview_id = (int) $_GET['preview_id'];

			} elseif ( isset( $_GET['p'] ) ) {

				$preview_id = (int) $_GET['p'];

			} elseif ( isset( $_GET['page_id'] ) ) {

				$preview_id = (int) $_GET['page_id'];

			}

			// bail early id $preview_id does not match $post_id
			if ( $preview_id != $post_id ) {
				return $post_id;
			}

			// attempt find revision
			$revision = acf_get_post_latest_revision( $post_id );

			// save
			if ( $revision && $revision->post_parent == $post_id ) {

				$post_id = (int) $revision->ID;

			}

			// set cache
			$this->cache[ $k ] = $post_id;

			// return
			return $post_id;

		}

	}

	// initialize
	acf()->revisions = new acf_revisions();

endif; // class_exists check


/*
*  acf_save_post_revision
*
*  This function will copy meta from a post to it's latest revision
*
*  @type    function
*  @date    26/09/2016
*  @since   5.4.0
*
*  @param   $post_id (int)
*  @return  n/a
*/

function acf_save_post_revision( $post_id = 0 ) {

	// get latest revision
	$revision = acf_get_post_latest_revision( $post_id );

	// save
	if ( $revision ) {

		acf_copy_postmeta( $post_id, $revision->ID );

	}

}


/*
*  acf_get_post_latest_revision
*
*  This function will return the latest revision for a given post
*
*  @type    function
*  @date    25/06/2016
*  @since   5.3.8
*
*  @param   $post_id (int)
*  @return  $post_id (int)
*/

function acf_get_post_latest_revision( $post_id ) {

	// vars
	$revisions = wp_get_post_revisions( $post_id );

	// shift off and return first revision (will return null if no revisions)
	$revision = array_shift( $revisions );

	// return
	return $revision;

}



