post-discussion-toggle.php

<?php
/*
Plugin Name: Post Discussion Toggle
Description: Per-post controls to force comments and pingbacks on or off, overriding global Discussion settings.
Version: 1.1.0
Author: Your Name
Text Domain: post-discussion-toggle
License: GPL2
*/

if ( ! defined( 'ABSPATH' ) ) {
    exit; // I'm not running this outside WordPress. Nice try.
}

class Post_Discussion_Toggle {

    const VERSION       = '1.1.0';

    // Meta keys: I only store explicit overrides, never "default".
    const META_COMMENTS = '_pdt_comments_status'; // 'open' | 'closed'
    const META_PINGS    = '_pdt_pings_status';    // 'open' | 'closed'

    // Status values.
    const STATUS_DEFAULT = 'default';
    const STATUS_OPEN    = 'open';
    const STATUS_CLOSED  = 'closed';

    public function __construct() {
        // Load translations if someone cares enough to localise this.
        add_action( 'plugins_loaded', array( $this, 'load_textdomain' ) );

        // Editor UI.
        add_action( 'add_meta_boxes', array( $this, 'add_meta_box' ) );
        add_action( 'save_post', array( $this, 'save_meta_box_data' ) );

        // Runtime behaviour.
        add_filter( 'comments_open', array( $this, 'filter_comments_open' ), 10, 2 );
        add_filter( 'pings_open', array( $this, 'filter_pings_open' ), 10, 2 );
    }

    /**
     * Load the text domain for translations.
     *
     * I'm wiring this in properly even if I never ship .po files.
     */
    public function load_textdomain() {
        load_plugin_textdomain(
            'post-discussion-toggle',
            false,
            dirname( plugin_basename( __FILE__ ) ) . '/languages/'
        );
    }

    /**
     * Decide which post types get the meta box.
     *
     * My rule:
     * - Public post types only.
     * - They must support comments.
     * Anything else is probably not meant to play in this space.
     */
    protected function get_supported_post_types() {
        $post_types = get_post_types(
            array(
                'public' => true,
            ),
            'objects'
        );

        $supported = array();

        foreach ( $post_types as $type => $obj ) {
            if ( post_type_supports( $type, 'comments' ) ) {
                $supported[] = $type;
            }
        }

        // Failsafe: if something strange happens, I at least support posts and pages.
        if ( empty( $supported ) ) {
            $supported = array( 'post', 'page' );
        }

        return $supported;
    }

    /**
     * Attach the meta box to all supported post types.
     */
    public function add_meta_box() {
        $screen_types = $this->get_supported_post_types();

        foreach ( $screen_types as $screen ) {
            add_meta_box(
                'pdt_discussion_controls',
                __( 'Discussion controls', 'post-discussion-toggle' ),
                array( $this, 'render_meta_box' ),
                $screen,
                'side',
                'default'
            );
        }
    }

    /**
     * Options I want to show in the dropdown.
     */
    protected function get_status_options() {
        return array(
            self::STATUS_DEFAULT => __( 'Use global setting', 'post-discussion-toggle' ),
            self::STATUS_OPEN    => __( 'Always allow', 'post-discussion-toggle' ),
            self::STATUS_CLOSED  => __( 'Always disallow', 'post-discussion-toggle' ),
        );
    }

    /**
     * Work out what the UI should display for a given meta key.
     *
     * Stored values are only 'open' or 'closed'. Anything else means "default".
     */
    protected function get_status_for_display( $post_id, $meta_key ) {
        $raw = get_post_meta( $post_id, $meta_key, true );

        if ( $raw === self::STATUS_OPEN || $raw === self::STATUS_CLOSED ) {
            return $raw;
        }

        return self::STATUS_DEFAULT;
    }

    /**
     * Render the meta box UI.
     *
     * This works in both Classic and Block editor, because meta boxes still exist
     * in Gutenberg, hiding in the advanced panel.
     *
     * If I ever feel like over-engineering, I can add a proper sidebar plugin
     * backed by register_post_meta() with show_in_rest.
     */
    public function render_meta_box( $post ) {
        wp_nonce_field( 'pdt_save_meta', 'pdt_meta_nonce' );

        $comments_status = $this->get_status_for_display( $post->ID, self::META_COMMENTS );
        $pings_status    = $this->get_status_for_display( $post->ID, self::META_PINGS );
        $options         = $this->get_status_options();
        ?>

        <p>
            <strong><?php esc_html_e( 'Comments', 'post-discussion-toggle' ); ?></strong><br>
            <label for="pdt_comments_status" class="screen-reader-text">
                <?php esc_html_e( 'Comments status override', 'post-discussion-toggle' ); ?>
            </label>
            <select name="pdt_comments_status" id="pdt_comments_status">
                <?php foreach ( $options as $value => $label ) : ?>
                    <option value="<?php echo esc_attr( $value ); ?>" <?php selected( $comments_status, $value ); ?>>
                        <?php echo esc_html( $label ); ?>
                    </option>
                <?php endforeach; ?>
            </select>
        </p>

        <p>
            <strong><?php esc_html_e( 'Pings / trackbacks', 'post-discussion-toggle' ); ?></strong><br>
            <label for="pdt_pings_status" class="screen-reader-text">
                <?php esc_html_e( 'Pings and trackbacks status override', 'post-discussion-toggle' ); ?>
            </label>
            <select name="pdt_pings_status" id="pdt_pings_status">
                <?php foreach ( $options as $value => $label ) : ?>
                    <option value="<?php echo esc_attr( $value ); ?>" <?php selected( $pings_status, $value ); ?>>
                        <?php echo esc_html( $label ); ?>
                    </option>
                <?php endforeach; ?>
            </select>
        </p>

        <p class="description">
            <?php esc_html_e( 'These options override the global Discussion settings for this item only.', 'post-discussion-toggle' ); ?>
        </p>
        <?php
    }

    /**
     * Normalise a status value coming in from $_POST.
     *
     * I'm deliberately strict here: anything unexpected is treated as "ignore".
     */
    protected function sanitise_status_from_request( $key ) {
        if ( ! isset( $_POST[ $key ] ) ) {
            return null;
        }

        $value = sanitize_text_field( wp_unslash( $_POST[ $key ] ) );

        $allowed = array(
            self::STATUS_DEFAULT,
            self::STATUS_OPEN,
            self::STATUS_CLOSED,
        );

        if ( ! in_array( $value, $allowed, true ) ) {
            return null;
        }

        return $value;
    }

    /**
     * Write a given status to post meta, following my own storage rules:
     *
     * - 'default' never gets stored (I delete any existing meta).
     * - 'open' or 'closed' are stored explicitly.
     *
     * This keeps the database clean instead of full of "default" noise.
     */
    protected function persist_status( $post_id, $meta_key, $status ) {
        if ( $status === null ) {
            return;
        }

        if ( $status === self::STATUS_DEFAULT ) {
            delete_post_meta( $post_id, $meta_key );
            return;
        }

        update_post_meta( $post_id, $meta_key, $status );
    }

    /**
     * Save handler for the meta box.
     *
     * Everything here is defensive:
     * - No autosave.
     * - No revisions.
     * - Nonce check.
     * - Capability check.
     */
    public function save_meta_box_data( $post_id ) {

        if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE ) {
            return;
        }

        if ( wp_is_post_revision( $post_id ) ) {
            return;
        }

        if ( ! isset( $_POST['pdt_meta_nonce'] ) || ! wp_verify_nonce( $_POST['pdt_meta_nonce'], 'pdt_save_meta' ) ) {
            return;
        }

        if ( ! current_user_can( 'edit_post', $post_id ) ) {
            return;
        }

        $comments_status = $this->sanitise_status_from_request( 'pdt_comments_status' );
        $pings_status    = $this->sanitise_status_from_request( 'pdt_pings_status' );

        $this->persist_status( $post_id, self::META_COMMENTS, $comments_status );
        $this->persist_status( $post_id, self::META_PINGS, $pings_status );
    }

    /**
     * Single place where I decide whether to override WordPress' opinion.
     */
    protected function apply_override_status( $open, $post_id, $meta_key ) {
        $status = get_post_meta( $post_id, $meta_key, true );

        if ( $status === self::STATUS_OPEN ) {
            // I'm forcing this open regardless of the global setting.
            return true;
        }

        if ( $status === self::STATUS_CLOSED ) {
            // And here I'm forcing it shut. Silence.
            return false;
        }

        // No override, I respect whatever WordPress already decided.
        return $open;
    }

    /**
     * comments_open filter handler.
     */
    public function filter_comments_open( $open, $post_id ) {
        $post_id = (int) $post_id;
        if ( $post_id <= 0 ) {
            // If WP gave me nonsense, I won't make it worse.
            return $open;
        }

        return $this->apply_override_status( $open, $post_id, self::META_COMMENTS );
    }

    /**
     * pings_open filter handler.
     */
    public function filter_pings_open( $open, $post_id ) {
        $post_id = (int) $post_id;
        if ( $post_id <= 0 ) {
            return $open;
        }

        return $this->apply_override_status( $open, $post_id, self::META_PINGS );
    }
}

new Post_Discussion_Toggle();