<?php
/**
 * Plugin Name: Cloudflare Cache Purger
 * Plugin URI: https://git.optimull.com/lsemenenko/cloudflare-cache-purger
 * Description: Automatically purges Cloudflare cache when specific WordPress hooks are fired.
 * Version: 1.0.0
 * Author: Leonid Semenenko
 * Author URI: https://optimull.com
 * License: GPL-2.0+
 * License URI: http://www.gnu.org/licenses/gpl-2.0.txt
 * Text Domain: cloudflare-cache-purger
 */

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

class Cloudflare_Cache_Purger {
        /**
         * Cloudflare API credentials.
         */
        private $api_token;
        private $zone_id;

        /**
         * Debug mode flag.
         */
        private $debug_mode;

        /**
         * Initialize the plugin.
         */
        public function __construct() {
                // Load settings.
                $this->load_settings();

                // Register hooks to purge cache.
                $this->register_hooks();

                // Add admin menu.
                add_action( 'admin_menu', array( $this, 'add_admin_menu' ) );
                add_action( 'admin_init', array( $this, 'register_settings' ) );
        }

        /**
         * Load settings from WordPress options.
         */
        private function load_settings() {
                $this->api_token   = get_option( 'cloudflare_cache_purger_api_token', '' );
                $this->zone_id     = get_option( 'cloudflare_cache_purger_zone_id', '' );
                $this->debug_mode  = get_option( 'cloudflare_cache_purger_debug', false );
        }

        /**
         * Register hooks that will trigger cache purge.
         */
        private function register_hooks() {
                // Hooks specified in requirements.
                add_action( 'pending_to_publish', array( $this, 'purge_cache' ) );
                add_action( 'publish_to_trash', array( $this, 'purge_cache' ) );
                add_action( 'future_to_publish', array( $this, 'purge_cache' ) );
                add_action( 'draft_to_publish', array( $this, 'purge_cache' ) );
                add_action( 'delete_attachment', array( $this, 'purge_cache' ) );
                add_action( 'autoptimize_action_cachepurged', array( $this, 'purge_cache' ) );
                add_action( 'switch_theme', array( $this, 'purge_cache' ) );
                add_action( 'customize_save_after', array( $this, 'purge_cache' ) );
        }

        /**
         * Write debug information to a log file in wp-content.
         *
         * @param string $message The debug message.
         */
        private function debug_log( $message ) {
                $log_file = WP_CONTENT_DIR . '/cloudflare-cache-purger-debug.log';
                $formatted_message = '[' . date( 'Y-m-d H:i:s' ) . '] ' . $message . "\n";
                file_put_contents( $log_file, $formatted_message, FILE_APPEND );
        }

        /**
         * Purge the Cloudflare cache.
         */
        public function purge_cache() {
                // Check if credentials are set.
                if ( empty( $this->api_token ) || empty( $this->zone_id ) ) {
                        error_log( 'Cloudflare Cache Purger: API credentials not set.' );
                        if ( $this->debug_mode ) {
                                $this->debug_log( 'API credentials not set.' );
                        }
                        return;
                }

                // Prepare request to Cloudflare API.
                $url     = "https://api.cloudflare.com/client/v4/zones/{$this->zone_id}/purge_cache";
                $headers = array(
                        'Authorization: Bearer ' . $this->api_token,
                        'Content-Type: application/json'
                );

                // Purge everything.
                $data = json_encode( array( 'purge_everything' => true ) );

                // Log the purge event if debug is enabled.
                if ( $this->debug_mode ) {
                        $this->debug_log( "Initiating cache purge. URL: $url, Data: $data" );
                }

                // Initialize cURL.
                $ch = curl_init();
                curl_setopt( $ch, CURLOPT_URL, $url );
                curl_setopt( $ch, CURLOPT_CUSTOMREQUEST, 'POST' );
                curl_setopt( $ch, CURLOPT_HTTPHEADER, $headers );
                curl_setopt( $ch, CURLOPT_POSTFIELDS, $data );
                curl_setopt( $ch, CURLOPT_RETURNTRANSFER, true );

                // Execute request.
                $result    = curl_exec( $ch );
                $http_code = curl_getinfo( $ch, CURLINFO_HTTP_CODE );

                // Close cURL.
                curl_close( $ch );

                // Log API response if debug is enabled.
                if ( $this->debug_mode ) {
                        $this->debug_log( "API response: HTTP Code: $http_code, Result: $result" );
                }

                // Log result to error_log and show admin notices.
                if ( $http_code >= 200 && $http_code < 300 ) {
                        error_log( 'Cloudflare Cache Purger: Cache successfully purged.' );
                        if ( is_admin() ) {
                                add_action( 'admin_notices', function() {
                                        echo '<div class="notice notice-success is-dismissible"><p>Cloudflare cache has been purged successfully.</p></div>';
                                } );
                        }
                } else {
                        error_log( 'Cloudflare Cache Purger: Failed to purge cache. Error: ' . $result );
                        if ( is_admin() ) {
                                add_action( 'admin_notices', function() use ( $result ) {
                                        $error_message = json_decode( $result, true );
                                        $message = isset( $error_message['errors'][0]['message'] ) ? $error_message['errors'][0]['message'] : 'Unknown error';
                                        echo '<div class="notice notice-error is-dismissible"><p>Failed to purge Cloudflare cache: ' . esc_html( $message ) . '</p></div>';
                                } );
                        }
                }
        }

        /**
         * Add admin menu.
         */
        public function add_admin_menu() {
                add_options_page(
                        'Cloudflare Cache Purger Settings',
                        'Cloudflare Cache',
                        'manage_options',
                        'cloudflare-cache-purger',
                        array( $this, 'settings_page' )
                );
        }

        /**
         * Register plugin settings.
         */
        public function register_settings() {
                register_setting( 'cloudflare_cache_purger', 'cloudflare_cache_purger_api_token' );
                register_setting( 'cloudflare_cache_purger', 'cloudflare_cache_purger_zone_id' );
                register_setting( 'cloudflare_cache_purger', 'cloudflare_cache_purger_debug' );

                add_settings_section(
                        'cloudflare_cache_purger_section',
                        'Cloudflare API Settings',
                        array( $this, 'settings_section_callback' ),
                        'cloudflare-cache-purger'
                );

                add_settings_field(
                        'cloudflare_cache_purger_api_token',
                        'Cloudflare API Token',
                        array( $this, 'api_token_field_callback' ),
                        'cloudflare-cache-purger',
                        'cloudflare_cache_purger_section'
                );

                add_settings_field(
                        'cloudflare_cache_purger_zone_id',
                        'Cloudflare Zone ID',
                        array( $this, 'zone_id_field_callback' ),
                        'cloudflare-cache-purger',
                        'cloudflare_cache_purger_section'
                );

                add_settings_field(
                        'cloudflare_cache_purger_debug',
                        'Enable Debug Logging',
                        array( $this, 'debug_field_callback' ),
                        'cloudflare-cache-purger',
                        'cloudflare_cache_purger_section'
                );
        }

        /**
         * Settings section description.
         */
        public function settings_section_callback() {
                echo '<p>Enter your Cloudflare API credentials to enable automatic cache purging.</p>';
                echo '<p>You can find your Zone ID in the Cloudflare dashboard under "Overview" > "API" section.</p>';
                echo '<p>Create an API token with the "Zone.Cache Purge" permission in the Cloudflare dashboard under "My Profile" > "API Tokens".</p>';
        }

        /**
         * API token field callback.
         */
        public function api_token_field_callback() {
                $api_token = get_option( 'cloudflare_cache_purger_api_token', '' );
                echo '<input type="password" id="cloudflare_cache_purger_api_token" name="cloudflare_cache_purger_api_token" value="' . esc_attr( $api_token ) . '" class="regular-text" />';
                echo '<p class="description">Your Cloudflare API token. Create one with "Zone.Cache Purge" permission.</p>';
        }

        /**
         * Zone ID field callback.
         */
        public function zone_id_field_callback() {
                $zone_id = get_option( 'cloudflare_cache_purger_zone_id', '' );
                echo '<input type="text" id="cloudflare_cache_purger_zone_id" name="cloudflare_cache_purger_zone_id" value="' . esc_attr( $zone_id ) . '" class="regular-text" />';
                echo '<p class="description">Your Cloudflare Zone ID for the domain.</p>';
        }

        /**
         * Debug field callback.
         */
        public function debug_field_callback() {
                $debug = get_option( 'cloudflare_cache_purger_debug', false );
                ?>
                <input type="checkbox" id="cloudflare_cache_purger_debug" name="cloudflare_cache_purger_debug" value="1" <?php checked( 1, $debug ); ?> />
                <p class="description">Enable debug logging. Debug messages will be saved to <code>wp-content/cloudflare-cache-purger-debug.log</code>.</p>
                <?php
        }

        /**
         * Settings page content.
         */
        public function settings_page() {
                // Check user capabilities.
                if ( ! current_user_can( 'manage_options' ) ) {
                        return;
                }
                ?>
                <div class="wrap">
                        <h1><?php echo esc_html( get_admin_page_title() ); ?></h1>
                        <form action="options.php" method="post">
                                <?php
                                settings_fields( 'cloudflare_cache_purger' );
                                do_settings_sections( 'cloudflare-cache-purger' );
                                submit_button( 'Save Settings' );
                                ?>
                        </form>

                        <div class="card">
                                <h2>Manual Cache Purge</h2>
                                <p>Click the button below to manually purge the Cloudflare cache.</p>
                                <form method="post" action="">
                                        <?php wp_nonce_field( 'manual_purge_action', 'manual_purge_nonce' ); ?>
                                        <input type="hidden" name="action" value="manual_purge">
                                        <input type="submit" class="button button-primary" value="Purge Cache">
                                </form>
                        </div>

                        <div class="card">
                                <h2>Automatic Purge Events</h2>
                                <p>This plugin automatically purges the Cloudflare cache when any of these WordPress events occur:</p>
                                <ul style="list-style-type: disc; margin-left: 20px;">
                                        <li>When a post is edited</li>
                                        <li>When a post is saved</li>
                                        <li>When a post is deleted</li>
                                        <li>When an attachment is deleted</li>
                                        <li>When Autoptimize purges its cache</li>
                                        <li>When a theme is switched</li>
                                        <li>When customizer changes are saved</li>
                                </ul>
                        </div>
                </div>
                <?php

                // Handle manual purge.
                if (
                        isset( $_POST['action'] ) &&
                        $_POST['action'] === 'manual_purge' &&
                        isset( $_POST['manual_purge_nonce'] ) &&
                        wp_verify_nonce( $_POST['manual_purge_nonce'], 'manual_purge_action' )
                ) {
                        $this->purge_cache();
                        echo '<div class="notice notice-info is-dismissible"><p>Manual cache purge initiated.</p></div>';
                }
        }
}

// Initialize the plugin.
$cloudflare_cache_purger = new Cloudflare_Cache_Purger();