humanmade / repeatable-posts

hm-post-repeat.php

<?php

/*
Plugin Name: Repeatable Posts
Description: Designate a post as repeatable and it'll be copied and re-published on your chosen interval.
Author: Human Made Limited
Author URI: http://hmn.md/
Version: 0.4
License: GPL-2.0+
License URI: http://www.gnu.org/licenses/gpl-2.0.txt
Text Domain: hm-post-repeat
Domain Path: /languages
*/

/*
Copyright Human Made Limited  (email : hello@hmn.md)

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

namespace HM\Post_Repeat;

/**
 * Setup the actions and filters required by this class.
 */
add_action( 'post_submitbox_misc_actions', __NAMESPACE__ . '\publish_box_ui' );
add_action( 'save_post',                   __NAMESPACE__ . '\manage_repeat_post', 10 );
add_action( 'admin_enqueue_scripts',       __NAMESPACE__ . '\enqueue_scripts' );
add_filter( 'display_post_states',         __NAMESPACE__ . '\admin_table_row_post_states', 10, 2 );

// Add repeat type table view links to admin screen for each CPT that supports Repeatable Posts.
add_action( 'init', function() {
	foreach ( repeating_post_types() as $post_type ) {
		add_filter( "views_edit-{$post_type}", __NAMESPACE__ . '\admin_table_views_links' );
	}
} );

// Display only Repeatable Posts in admin table view for registered view links.
add_filter( 'pre_get_posts', __NAMESPACE__ . '\admin_table_repeat_type_posts_query' );

/**
 * Enqueue the scripts and styles that are needed by this plugin.
 */
function enqueue_scripts( $hook ) {

	// Ensure we only load them on the edit post and add new post admin screens
	if ( ! in_array( $hook, array( 'post.php', 'post-new.php' ) ) ) {
		return;
	}

	$plugin_data = get_plugin_data( __FILE__ );
	$plugin_dir_url = plugin_dir_url( __FILE__ );

	wp_enqueue_script( 'hm-post-repeat', $plugin_dir_url . 'hm-post-repeat.js', 'jquery', $plugin_data['Version'], true );
	wp_enqueue_style( 'hm-post-repeat', $plugin_dir_url . 'hm-post-repeat.css', array(), $plugin_data['Version'] );

}

/**
 * Output the Post Repeat UI that is shown in the Publish post meta box.
 *
 * The UI varies depending on whether the post is the original repeating post
 * or itself a repeat.
 */
function publish_box_ui() {

	if ( ! in_array( get_post_type(), repeating_post_types() ) ) {
		return;
	} ?>

	<div class="misc-pub-section misc-pub-hm-post-repeat">

		<span class="dashicons dashicons-controls-repeat"></span>

		<?php esc_html_e( 'Repeat:', 'hm-post-repeat' ); ?>

		<?php if ( is_repeat_post( get_the_id() ) ) : ?>

			<strong><?php printf( esc_html__( 'Repeat of %s', 'hm-post-repeat' ), '<a href="' . esc_url( get_edit_post_link( get_post()->post_parent ) ) . '">' . esc_html( get_the_title( get_post_field( 'post_parent', get_the_id() ) ) ) . '</a>' ); ?></strong>

		<?php else : ?>

			<?php $repeating_schedule = get_repeating_schedule( get_the_id() ); ?>
			<?php $is_repeating_post = is_repeating_post( get_the_id() ) && isset( $repeating_schedule ); ?>

			<strong><?php echo ! $is_repeating_post ? esc_html__( 'No', 'hm-post-repeat' ) : esc_html( $repeating_schedule['display'] ); ?></strong>

			<a href="#hm-post-repeat" class="edit-hm-post-repeat hide-if-no-js"><span aria-hidden="true"><?php esc_html_e( 'Edit', 'hm-post-repeat' ); ?></span> <span class="screen-reader-text"><?php esc_html_e( 'Edit Repeat Settings', 'hm-post-repeat' ); ?></span></a>

			<span class="hide-if-js" id="hm-post-repeat">

				<select name="hm-post-repeat">
					<option<?php selected( ! $is_repeating_post ); ?> value="no"><?php esc_html_e( 'No', 'hm-post-repeat' ); ?></option>
					<?php foreach ( get_repeating_schedules() as $schedule_slug => $schedule ) : ?>
						<option<?php selected( $is_repeating_post && $schedule_slug === $repeating_schedule['slug'] ); ?> value="<?php echo esc_attr( $schedule_slug ); ?>"><?php echo esc_html( $schedule['display'] ); ?></option>
					<?php endforeach; ?>
				</select>

				<a href="#hm-post-repeat" class="save-post-hm-post-repeat hide-if-no-js button"><?php esc_html_e( 'OK', 'hm-post-repeat' ); ?></a>

			</span>

		<?php endif; ?>

	</div>

<?php }

/**
 * Add some custom post states to cover repeat and repeating posts.
 *
 * By default post states are displayed on the Edit Post screen in bold after the post title.
 *
 * @param array   $post_states The original array of post states.
 * @param WP_Post $post        The post object to get / return the states.
 * @return array The array of post states with ours added.
 */
function admin_table_row_post_states( $post_states, $post ) {

	if ( is_repeating_post( $post->ID ) ) {

		// If the schedule has been removed since publishing, let the user know.
		if ( get_repeating_schedule( $post->ID ) ) {
			$post_states['hm-post-repeat'] = __( 'Repeating', 'hm-post-repeat' );
		} else {
			$post_states['hm-post-repeat'] = __( 'Invalid Repeating Schedule', 'hm-post-repeat' );
		}

	}

	if ( is_repeat_post( $post->ID ) ) {
		$post_states['hm-post-repeat'] = __( 'Repeat', 'hm-post-repeat' );
	}

	return $post_states;
}

/**
 * Manage Repeating Post functionality:
 *
 * 1. Correctly mark/un-mark a Repeating post as such (i.e. save/delete the Repeating Schedule to/from post meta).
 * 2. Manage cleanup and creation of a corresponding Repeat post.
 *
 * @param int $post_id                The ID of the (Repeating or Repeat) post being saved.
 *                                    NB: Used to manually set the Repeating post ID from tests.
 * @param string $post_repeat_setting Repeating Schedule setting (daily, weekly, etc).
 *                                    NB: Used to manually set the Repeating Schedule for a post from tests.
 */
function manage_repeat_post( $post_id = null, $post_repeat_setting = null ) {

	// Not running a phpunit test - check if Repeating Schedule setting value is present when saving a post.
	if ( is_null( $post_repeat_setting ) ) {
		$post_repeat_setting = isset( $_POST['hm-post-repeat'] ) ? sanitize_text_field( $_POST['hm-post-repeat'] ) : '';
	}

	/**
	 * Stop - if:
	 * 1. Post type doesn't support Repeating Posts feature.
	 * 2. Not processing a Repeat post.
	 * 3. Not processing a Repeating post (i.e. Repeating Schedule isn't specified).
	 */
	if (
			! in_array( get_post_type( $post_id ), repeating_post_types() ) ||
			( ! is_repeat_post( $post_id ) && empty( $post_repeat_setting ) )
	) {
		return;
	}

	// Repeating post - save the specified Repeating Schedule and manage a Repeat post.
	if ( $post_repeat_setting ) {

		// Repeating Schedule is removed - i.e. the post is no longer Repeating.
		if ( 'no' === $post_repeat_setting ) {

			// Remove post meta from the Repeating post.
			delete_post_meta( $post_id, 'hm-post-repeat' );

			// Clean up the currently scheduled Repeat post if any.
			delete_next_scheduled_repeat_post( $post_id );
		}
		// Repeating Schedule is specified and valid - save it to post's meta and manage a Repeat post.
		elseif ( in_array( $post_repeat_setting, array_keys( get_repeating_schedules() ) ) ) {

			/**
			 * Clean up the currently scheduled Repeat post if any. This takes care of cases when:
			 * 1. Repeating Schedule has changed.
			 * 2. Content of the Repeating post is changed.
			 *
			 * In such cases, the next scheduled post should reflect these changes.
			 */
			delete_next_scheduled_repeat_post( $post_id );

			// Update a Repeating Schedule for the current post.
			update_post_meta( $post_id, 'hm-post-repeat', $post_repeat_setting );

			// Schedule a Repeat post.
			create_next_repeat_post( $post_id );
		}
	}

	// Repeat post - is published, schedule a next Repeat post.
	if ( is_repeat_post( $post_id ) && 'publish' === get_post_status( $post_id ) ) {

		create_next_repeat_post( $post_id );
	}
}

/**
 * Create the next Repeat post when:
 * 1. a Repeating post is published or already published post is re-saved.
 * 2. a previously scheduled Repeat post is published.
 *
 * In such cases we copy the Repeating post and schedule a new Repeat post to publish on the correct interval.
 * This way the next Repeat post is always ready to go.
 *
 * @param int $post_id The ID of the (Repeating or Repeat) post being saved.
 *
 * @return int|\WP_Error A scheduled Repeat post ID on success,
 *                       WP_Error if a Repeat post could not be created.
 *                       Terminate function execution if conditions are not met.
 */
function create_next_repeat_post( $post_id ) {

	// Stop - post type doesn't support Repeating Posts feature.
	if ( ! in_array( get_post_type( $post_id ), repeating_post_types() ) ) {
		return false;
	}

	// Stop - the current post isn't being published.
	if ( 'publish' !== get_post_status( $post_id ) ) {
		return false;
	}

	// Get the Repeating post ID for the current post being saved (which in turn can be a Repeating or Repeat post).
	$original_post_id = get_repeating_post( $post_id );

	if ( ! $original_post_id ) {
		return false;
	}

	// Get the original Repeating post.
	$original_post = get_post( $original_post_id, ARRAY_A );

	// Stop - the original Repeating post isn't already published.
	if ( 'publish' !== $original_post['post_status'] ) {
		return false;
	}

	// Stop - there is already a Repeat post scheduled don't create another one.
	if ( get_next_scheduled_repeat_post( $original_post['ID'] ) ) {
		return false;
	}

	// Get Repeating Schedule.
	$repeating_schedule = get_repeating_schedule( $original_post['ID'] );

	if ( ! $repeating_schedule ) {
		return false;
	}

	$next_post = $original_post;

	// Create the Repeat post as a copy of the original, but ignore some fields.
	unset( $next_post['ID'] );
	unset( $next_post['guid'] );
	unset( $next_post['post_date_gmt'] );
	unset( $next_post['post_modified'] );
	unset( $next_post['post_modified_gmt'] );

	// Set the post_parent to the original Repeating post_id, so they're related.
	$next_post['post_parent'] = $original_post['ID'];

	// Set the next Repeat post to publish in the future.
	$next_post['post_status'] = 'future';

	// Use the date of the current post being saved as the base.
	$next_post['post_date'] = date( 'Y-m-d H:i:s', strtotime( get_post_field( 'post_date', $post_id ) . ' + ' . $repeating_schedule['interval'] ) );

	// Make sure the next post will be in the future from the current time.
	if ( strtotime( $next_post['post_date'] ) <= time() ) {
		return false;
	}

	/**
	 * Use this filter to modify the scheduled post before it gets stored.
	 *
	 * @param array $next_post          The post data about to be saved.
	 * @param array $repeating_schedule Repeating schedule info.
	 * @param array $original_post      The original repeating post.
	 */
	$next_post = apply_filters( 'hm_post_repeat_edit_repeat_post', $next_post, $repeating_schedule, $original_post );

	/**
	 * Remove and then re-add our custom functionality hooked in into `save_post` filter.
	 * This is due to inserting a Repeat post using `wp_insert_post()` which in turn
	 * calls the `save_post` filters again.
	 *
	 * We want our custom functionality to run on the `save_post` filter only once.
	 */
	remove_action( 'save_post', __NAMESPACE__ . '\\manage_repeat_post' );

	// All checks done, get that post scheduled!
	$next_post_id = wp_insert_post( wp_slash( $next_post ), true );

	add_action( 'save_post', __NAMESPACE__ . '\\manage_repeat_post' );

	if ( is_wp_error( $next_post_id ) ) {
		return false;
	}

	// Mirror any post meta.
	$post_meta = get_post_meta( $original_post['ID'] );

	if ( $post_meta ) {

		// Ignore some internal meta fields.
		unset( $post_meta['_edit_lock'] );
		unset( $post_meta['_edit_last'] );

		// Don't copy the post Repeating Schedule meta as only the original Repeating post should have that.
		unset( $post_meta['hm-post-repeat'] );

		foreach ( $post_meta as $key => $values ) {
			foreach ( $values as $value ) {
				add_post_meta( $next_post_id, $key, maybe_unserialize( $value ) );
			}
		}
	}

	// Mirror any term relationships.
	$taxonomies = get_object_taxonomies( $original_post['post_type'] );

	foreach ( $taxonomies as $taxonomy ) {
		wp_set_object_terms( $next_post_id, wp_list_pluck( wp_get_object_terms( $original_post['ID'], $taxonomy ), 'slug' ), $taxonomy );
	}

	return $next_post_id;
}

/**
 * The post types the feature is enabled on
 *
 * By default only posts have the feature enabled but others can be added with the `hm_post_repeat_post_types` filter.
 *
 * @return array An array of post types
 */
function repeating_post_types() {

	/**
	 * Enable support for additional post types.
	 *
	 * @param string[] $post_types Post type slugs.
	 */
	return apply_filters( 'hm_post_repeat_post_types', array( 'post' ) );

}

/**
 * All available repeat schedules.
 *
 * @return array An array of all available repeat schedules
 */
function get_repeating_schedules() {

	/**
	 * Enable support for additional schedules.
	 *
	 * @param array[] $schedules Schedule array items.
	 */
	$schedules = apply_filters( 'hm_post_repeat_schedules', array(
		'daily'   => array( 'interval' => '1 day',   'display' => __( 'Daily',   'hm-post-repeat' ) ),
		'weekly'  => array( 'interval' => '1 week',  'display' => __( 'Weekly',  'hm-post-repeat' ) ),
		'monthly' => array( 'interval' => '1 month', 'display' => __( 'Monthly', 'hm-post-repeat' ) ),
	) );

	foreach ( $schedules as $slug => &$schedule ) {
		$schedule['slug'] = $slug;
	}

	return $schedules;

}

/**
 * Get the repeating schedule of the given post_id.
 *
 * @param int $post_id The id of the post you want to check.
 * @return array|null The schedule to repeat by, or null if invalid.
 */
function get_repeating_schedule( $post_id ) {

	if ( ! is_repeating_post( $post_id ) ) {
		return;
	}

	$repeating_schedule = get_post_meta( $post_id, 'hm-post-repeat', true );
	$schedules = get_repeating_schedules();

	// Backwards compatibility with 0.3 when we only supported weekly
	if ( '1' === $repeating_schedule ) {
		$repeating_schedule = 'weekly';
	}

	if ( array_key_exists( $repeating_schedule, $schedules ) ) {
		return $schedules[ $repeating_schedule ];
	}

}

/**
 * Check whether a given post_id is a repeating post.
 *
 * A repeating post is defined as the original post that was set to repeat.
 *
 * @param int $post_id The id of the post you want to check.
 * @return bool Whether the passed post_id is a repeating post or not.
 */
function is_repeating_post( $post_id ) {

	// We check $_POST data so that this function works inside a `save_post` hook when the post_meta hasn't yet been saved
	if ( isset( $_POST['hm-post-repeat'] ) && isset( $_POST['ID'] ) && $_POST['ID'] === $post_id ) {
		return true;
	}

	if ( get_post_meta( $post_id, 'hm-post-repeat', true ) ) {
		return true;
	}

	return false;

}

/**
 * Check whether a given post_id is a repeat post.
 *
 * A repeat post is defined as any post which is a repeat of the original repeating post.
 *
 * @param int $post_id The id of the post you want to check.
 * @return bool Whether the passed post_id is a repeat post or not.
 */
function is_repeat_post( $post_id ) {

	$post_parent = get_post_field( 'post_parent', $post_id );

	if ( $post_parent && get_post_meta( $post_parent, 'hm-post-repeat', true ) ) {
		return true;
	}

	return false;
}

/**
 * Delete currently scheduled i.e. future Repeat posts for the specified post.
 *
 * @param $post_id The ID of a Repeat or Repeating post to delete scheduled posts for.
 */
function delete_next_scheduled_repeat_post( $post_id ) {

	// TO DO: will it ever be more than 1 scheduled post?
	$next_repeat_post = get_next_scheduled_repeat_post( $post_id );

	if ( $next_repeat_post ) {
		// TO DO: should we trash or permanently delete? I think permanently delete.
		wp_delete_post( $next_repeat_post->ID, true );
	}
}

/**
 * Get the next scheduled repeat post.
 *
 * @param int $post_id The ID of a Repeat or Repeating post.
 *
 * @return int|bool Return the ID of the next repeat post_id or false if it can't find one.
 */
function get_next_scheduled_repeat_post( $post_id ) {

	$post = get_post( get_repeating_post( $post_id ) );

	$repeat_posts = get_posts( array( 'post_status' => 'future', 'post_parent' => $post->ID ) );

	if ( isset( $repeat_posts[0] ) ) {
		return $repeat_posts[0];
	}

	return false;
}

/**
 * Get the next scheduled repeat post.
 *
 * @param int $post_id The ID of a Repeat or Repeating post.
 *
 * @return int|bool Return the original repeating post_id or false if it can't find it.
 */
function get_repeating_post( $post_id ) {

	$original_post_id = false;

	// Are we publishing a Repeat post.
	if ( is_repeat_post( $post_id ) ) {
		$original_post_id = get_post( $post_id )->post_parent;
	}

	// Or the original Repeating post.
	elseif ( is_repeating_post( $post_id ) ) {
		$original_post_id = $post_id;
	}

	return $original_post_id;
}

/**
 * Adds admin table view link per available repeat type.
 * So that only all posts of specific repeat type are displayed.
 *
 * Added at the end of link list for All | Mine | Published | Scheduled | Drafts
 *
 * @param array $views An array of available list table views.
 *
 * @return array Available list of table views with custom added views per repeat type.
 */
function admin_table_views_links( $views ) {

	// Add status link for each repeat type.
	foreach ( get_available_repeat_types() as $repeat_type => $repeat_desc ) {

		$url_args = array(
			'post_type'      => get_current_screen()->post_type,
			'hm-post-repeat' => $repeat_type,
		);

		// Custom WP_Query to get posts count of repeat type.
		$repeat_type_query = new \WP_Query( get_repeat_type_query_params( $repeat_type ) );

		$link_label = sprintf(
				'%s <span class="count">(%s)</span>',
			esc_html( $repeat_desc ),
			esc_html( number_format_i18n( $repeat_type_query->post_count ) )
		);

		// Add current class to the link to highlight it when it's selected.
		$class_html = ( get_repeat_type_url_param() === $repeat_type ) ? ' class="current"' : '';

		$link_html = sprintf(
			'<a href="%s"%s>%s</a>',
			esc_url( add_query_arg( $url_args, 'edit.php' ) ),
			$class_html, // html - hardcoded, no need to escape.
			$link_label  // html - escaped earlier in the code.
		);

		$views[ $repeat_type ] = $link_html;
	}

	return $views;
}

/**
 * Customizes main admin query to get posts of specified repeat type
 * to be displayed in the admin table.
 *
 * @param \WP_Query $wp_query Main admin query.
 *
 * @return mixed Main admin query with edited params to get posts of specified repeat type.
 */
function admin_table_repeat_type_posts_query( $wp_query ) {

	// Stop - if not admin or not main query (there are secondary WP_Query for counting posts for view links, etc).
	if ( ! is_admin() || ! $wp_query->is_main_query() ) {
		return $wp_query;
	}

	// Get URL query param for repeat type and check it's valid.
	$repeat_type = get_repeat_type_url_param();

	if ( ! $repeat_type || ! is_allowed_repeat_type( $repeat_type ) ) {
		return $wp_query;
	}

	// Add a table view link per each repeat type.
	foreach ( get_repeat_type_query_params( $repeat_type ) as $key => $value ) {
		$wp_query->set( $key, $value );
	}

	return $wp_query;
}

/**
 * Returns array of custom WP_Query params to get posts of specified repeat type.
 * Works for all CPT that support Repeatable Posts.
 *
 * @param string $repeat_type Repeat type of posts to get.
 *
 * @return array Array of custom WP_Query params.
 */
function get_repeat_type_query_params( $repeat_type ) {

	$query['post_type'] = get_current_screen()->post_type;

$query was never initialized. Although not strictly required by PHP, it is generally a good practice to add $query = array(); before regardless.

	// Construct custom query to get posts of specified repeat type.
	$query['meta_query'] = array(
			array(
					'key'     => 'hm-post-repeat',
					'compare' => 'EXISTS',
			),
	);

	if ( $repeat_type === 'repeat' ) {
		$query['post_parent__not_in'] = array( 0 );

	} elseif ( $repeat_type === 'repeating' ) {
		$query['post_parent__in'] = array( 0 );
	}

	return $query;
}

/**
 * Get URL query param for the repeat type of posts being displayed
 * in the admin post table.
 *
 * @return string Sanitized string of repeat type being displayed.
 */
function get_repeat_type_url_param() {
	return isset( $_GET['hm-post-repeat'] ) ? sanitize_text_field( $_GET['hm-post-repeat'] ) : '';
}

/**
 * Return available repeat types, i.e. repeating or repeat.
 *
 * @return array Available repeat types.
 */
function get_available_repeat_types() {
	return array(
		'repeating' => __( 'Repeating', 'hm-post-repeat' ),
		'repeat'    => __( 'Repeat', 'hm-post-repeat' ),
	);
}

/**
 * Check if a repeat type is valid.
 *
 * @param string $repeat_type Repeat type to check.
 *
 * @return bool True if repeat type is valid,
 *              False otherwise.
 */
function is_allowed_repeat_type( $repeat_type ) {
	return in_array( $repeat_type, array_keys( get_available_repeat_types() ) );
}