T5 Enforce Open Comments

t5-enforce-open-comments.php

<?php # -*- coding: utf-8 -*-
/**
 * Plugin Name: T5 Enforce Open Comments
 * Description: Override auto-closing for individual posts
 * Plugin URI:  http://toscho.de
 * Version:     2013.09.29
 * Author:      Thomas Scholz
 * Author URI:  http://toscho.de
 * Licence:     MIT
 * License URI: http://opensource.org/licenses/MIT
 * Textdomain:  plugin_t5_enforce_open_comments
 * Domain Path: /languages
 */

add_action( 'wp_loaded', 't5_efoc_init' );

function t5_efoc_init()
{
	if ( ! get_option( 'close_comments_for_old_posts' ) )
		return; // haha

	new T5_Enforce_Open_Comments( '_t5_efoc' );
}

class T5_Enforce_Open_Comments
{
	protected $key, $post_types;

	/**
	 * Constructor.
	 *
	 * @wp-hook wp_loaded
	 * @param   string    $key Post meta field name
	 */
	public function __construct( $key )
	{
		$this->key        = $key;

		// this is a core filter. we have to use it to catch custom post types
		$this->post_types = apply_filters(
			'close_comments_for_post_types',
			array( 'post' )
		);

		$this->register_hooks();
	}

	/**
	 * Add a checkbox to post edit screen under Discussion.
	 *
	 * @wp-hook post_comment_status_meta_box-options
	 * @param   object $post
	 * @return  void
	 */
	public function show_checkbox( $post )
	{
		if ( ! isset ( $post->post_type )
			or ! in_array( $post->post_type, $this->post_types )
			)
			return;

		printf(
			'<br /><label for="%1$s">
			<input type="checkbox" value="1" id="%1$s" name="%1$s" class="selectit" %2$s/> %3$s
			</label>',
			$this->key,
			checked( 1, $this->get_status( $post->ID ), FALSE ),
			__( 'Enforce open comments', 'plugin_t5_enforce_open_comments' )
		);
	}

	/**
	 * Save post meta field.
	 *
	 * @wp-hook save_post
	 * @param   int       $post_id
	 * @return  boolean For tests only, WP ignores any return value here.
	 */
	public function save_status( $post_id )
	{
		// AJAX autosave
		if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE )
			return FALSE;

		// Some other POST request
		if ( ! isset ( $_POST[ 'post_type' ] ) )
			return FALSE;

		// Missing capability
		if ( ! current_user_can( 'edit_' . $_POST[ 'post_type' ], $post_id ) )
			return FALSE;

		// Checkbox successfully clicked
		if ( isset ( $_POST[ $this->key ] ) and '1' === $_POST[ $this->key ] )
			return update_post_meta( $post_id, $this->key, 1 );

		// Checkbox deselected
		return delete_post_meta( $post_id, $this->key );
	}

	/**
	 * Change comment and ping status for a post.
	 *
	 * @wp-hook the_posts
	 * @param   array    $posts
	 * @param   WP_Query $query
	 * @return  array
	 */
	public function filter_the_posts( $posts, $query )
	{
		if ( empty ( $posts ) || ! $query->is_singular() )
			return $posts;

		if ( ! in_array( $posts[ 0 ]->post_type, $this->post_types ) )
			return $posts;

		if ( ! $this->get_status( $posts[ 0 ]->ID ) )
			return $posts;

		$posts[0]->comment_status = 'open';
		$posts[0]->ping_status    = 'open';

		return $posts;
	}

	/**
	 * Change status for comments and pings.
	 *
	 * @wp-hook comments_open
	 * @wp-hook pings_open
	 * @param   boolean       $open
	 * @param   int           $post_id
	 * @return  boolean
	 */
	public function filter_comments_and_pings( $open, $post_id )
	{
		if ( ! $post_id ) // is sometimes NULL
			$post_id = get_the_ID();

		if ( $this->get_status( $post_id ) )
			return TRUE;

		return $open;
	}

	/**
	 * Register callbacks for actions and filters.
	 *
	 * @wp-hook wp_loaded
	 * @return  void
	 */
	protected function register_hooks()
	{
		add_action(
			'post_comment_status_meta_box-options',
			array ( $this, 'show_checkbox' )
		);
		add_action(
			'save_post',
			array ( $this, 'save_status' )
		);
		add_filter(
			'comments_open',
			array ( $this, 'filter_comments_and_pings' ),
			11,
			2
		);
		add_filter(
			'pings_open',
			array ( $this, 'filter_comments_and_pings' ),
			11,
			2
		);
		add_filter(
			'the_posts',
			array ( $this, 'filter_the_posts' ),
			11,
			2
		);
	}

	/**
	 * Get enforced comment status for a post.
	 *
	 * @param  int $post_id
	 * @return int
	 */
	protected function get_status( $post_id )
	{
		return get_post_meta( $post_id, $this->key, TRUE ) ? 1 : 0;
	}
}