<?php
/**
 * Main Plugin Class
 *
 * Orchestrates plugin initialization and component integration.
 *
 * @package ROBOTSTXT_OG
 * @since 1.0.0
 */

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

/**
 * Class Robotstxt_OG_Image_Fallback
 *
 * Main plugin class using singleton pattern.
 *
 * @since 1.0.0
 */
class Robotstxt_OG_Image_Fallback {

	/**
	 * Single instance of the class.
	 *
	 * @since 1.0.0
	 * @var Robotstxt_OG_Image_Fallback|null
	 */
	private static ?Robotstxt_OG_Image_Fallback $instance = null;

	/**
	 * Image resolver instance.
	 *
	 * @since 1.0.0
	 * @var Robotstxt_OG_Image_Resolver
	 */
	private Robotstxt_OG_Image_Resolver $resolver;

	/**
	 * OG tags generator instance.
	 *
	 * @since 1.0.0
	 * @var Robotstxt_OG_Tags
	 */
	private Robotstxt_OG_Tags $tags;

	/**
	 * Admin settings instance.
	 *
	 * @since 1.0.0
	 * @var Robotstxt_OG_Admin_Settings|null
	 */
	private ?Robotstxt_OG_Admin_Settings $admin_settings = null;

	/**
	 * REST API instance.
	 *
	 * @since 1.0.0
	 * @var Robotstxt_OG_REST_API
	 */
	private Robotstxt_OG_REST_API $rest_api;

	/**
	 * Meta box instance.
	 *
	 * @since 1.2.0
	 * @var Robotstxt_OG_Meta_Box
	 */
	private Robotstxt_OG_Meta_Box $meta_box;

	/**
	 * Term meta instance.
	 *
	 * @since 1.2.0
	 * @var Robotstxt_OG_Term_Meta
	 */
	private Robotstxt_OG_Term_Meta $term_meta;

	/**
	 * Manager plugin notice instance.
	 *
	 * @since 1.2.1
	 * @var Robotstxt_OG_Manager_Notice|null
	 */
	private ?Robotstxt_OG_Manager_Notice $manager_notice = null;

	/**
	 * Get singleton instance.
	 *
	 * @since 1.0.0
	 *
	 * @return Robotstxt_OG_Image_Fallback
	 */
	public static function get_instance(): Robotstxt_OG_Image_Fallback {
		if ( null === self::$instance ) {
			self::$instance = new self();
		}

		return self::$instance;
	}

	/**
	 * Constructor.
	 *
	 * Private to enforce singleton pattern.
	 *
	 * @since 1.0.0
	 */
	private function __construct() {
		// Constructor is private.
	}

	/**
	 * Initialize the plugin.
	 *
	 * @since 1.0.0
	 *
	 * @return void
	 */
	public function init(): void {
		// Load bundled translations (required for non-wordpress.org distribution).
		load_plugin_textdomain( 'robotstxt-og', false, basename( ROBOTSTXT_OG_PATH ) . '/languages' );

		// Load dependencies.
		$this->load_dependencies();

		// Initialize components.
		$this->resolver = new Robotstxt_OG_Image_Resolver();
		$this->tags     = new Robotstxt_OG_Tags( $this->resolver );

		// Initialize OG tags generator.
		$this->tags->init();

		// Initialize REST API.
		$this->rest_api = new Robotstxt_OG_REST_API( $this->resolver );
		$this->rest_api->init();

		// Initialize meta box (registers post meta for REST + editor UI).
		$this->meta_box = new Robotstxt_OG_Meta_Box();
		$this->meta_box->init();

		// Initialize term meta (category/tag OG fields on term.php).
		$this->term_meta = new Robotstxt_OG_Term_Meta();
		$this->term_meta->init();

		// Initialize admin settings if in admin context.
		if ( is_admin() ) {
			$this->admin_settings = new Robotstxt_OG_Admin_Settings( $this->resolver );
			$this->admin_settings->init();

			$this->manager_notice = new Robotstxt_OG_Manager_Notice();
			$this->manager_notice->init();
		}

		// Register WP-CLI commands.
		if ( defined( 'WP_CLI' ) && WP_CLI ) {
			WP_CLI::add_command( 'og-fallback', new Robotstxt_OG_CLI( $this->resolver ) );
		}

		// Auto-regenerate cache when featured image changes.
		add_action( 'updated_post_meta', array( $this, 'handle_thumbnail_change' ), 10, 4 );
		add_action( 'deleted_post_meta', array( $this, 'handle_thumbnail_change' ), 10, 4 );

		// Register GDPR privacy data handlers.
		add_filter( 'wp_privacy_personal_data_exporters', array( $this, 'register_privacy_exporter' ) );
		add_filter( 'wp_privacy_personal_data_erasers', array( $this, 'register_privacy_eraser' ) );

		// Register activation and deactivation hooks.
		register_activation_hook( ROBOTSTXT_OG_PATH . 'robotstxt-og.php', array( $this, 'activate' ) );
		register_deactivation_hook( ROBOTSTXT_OG_PATH . 'robotstxt-og.php', array( $this, 'deactivate' ) );
	}

	/**
	 * Load plugin dependencies.
	 *
	 * @since 1.0.0
	 *
	 * @return void
	 */
	private function load_dependencies(): void {
		require_once ROBOTSTXT_OG_PATH . 'includes/class-robotstxt-og-image-resolver.php';
		require_once ROBOTSTXT_OG_PATH . 'includes/class-robotstxt-og-tags.php';
		require_once ROBOTSTXT_OG_PATH . 'includes/class-robotstxt-og-rest-api.php';
		require_once ROBOTSTXT_OG_PATH . 'includes/class-robotstxt-og-meta-box.php';
		require_once ROBOTSTXT_OG_PATH . 'includes/class-robotstxt-og-term-meta.php';

		// Load admin class if in admin context.
		if ( is_admin() ) {
			require_once ROBOTSTXT_OG_PATH . 'admin/class-robotstxt-og-admin-settings.php';
			require_once ROBOTSTXT_OG_PATH . 'includes/class-robotstxt-og-manager-notice.php';
		}

		// Load WP-CLI class if running in CLI context.
		if ( defined( 'WP_CLI' ) && WP_CLI ) {
			require_once ROBOTSTXT_OG_PATH . 'includes/class-robotstxt-og-cli.php';
		}
	}

	/**
	 * Activation hook callback.
	 *
	 * Runs when the plugin is activated.
	 *
	 * @since 1.0.0
	 *
	 * @return void
	 */
	public function activate(): void {
		// Set default options if they don't exist.
		if ( false === get_option( 'robotstxt_og_fallback_image' ) ) {
			add_option( 'robotstxt_og_fallback_image', '' );
		}

		if ( false === get_option( 'robotstxt_og_delete_data_on_uninstall' ) ) {
			add_option( 'robotstxt_og_delete_data_on_uninstall', false );
		}

		// Flush rewrite rules (if needed in future).
		flush_rewrite_rules();
	}

	/**
	 * Deactivation hook callback.
	 *
	 * Runs when the plugin is deactivated.
	 *
	 * @since 1.0.0
	 *
	 * @return void
	 */
	public function deactivate(): void {
		// Flush rewrite rules (if needed in future).
		flush_rewrite_rules();
	}

	/**
	 * Clear fallback cache when a post's featured image is changed or removed.
	 *
	 * Hooked to `updated_post_meta` and `deleted_post_meta` for `_thumbnail_id`.
	 *
	 * @since 1.0.0
	 *
	 * @param int|int[] $meta_id    ID or array of IDs of the meta data entry.
	 * @param int       $post_id    Post ID.
	 * @param string    $meta_key   Meta key being updated.
	 * @param mixed     $meta_value New meta value (unused).
	 * @return void
	 */
	public function handle_thumbnail_change( int|array $meta_id, int $post_id, string $meta_key, $meta_value = null ): void { // phpcs:ignore Generic.CodeAnalysis.UnusedFunctionParameter.FoundAfterLastUsed
		if ( '_thumbnail_id' !== $meta_key ) {
			return;
		}

		$this->resolver->clear_cache( $post_id );
	}

	/**
	 * Register the personal data exporter.
	 *
	 * @since 1.0.3
	 *
	 * @param array<int, array<string, mixed>> $exporters List of exporters.
	 * @return array<int, array<string, mixed>> Updated exporters list.
	 */
	public function register_privacy_exporter( array $exporters ): array {
		$exporters[] = array(
			'exporter_friendly_name' => __( 'OpenGraph Custom Post Data', 'robotstxt-og' ),
			'callback'               => array( $this, 'export_privacy_data' ),
		);
		return $exporters;
	}

	/**
	 * Register the personal data eraser.
	 *
	 * @since 1.0.3
	 *
	 * @param array<int, array<string, mixed>> $erasers List of erasers.
	 * @return array<int, array<string, mixed>> Updated erasers list.
	 */
	public function register_privacy_eraser( array $erasers ): array {
		$erasers[] = array(
			'eraser_friendly_name' => __( 'OpenGraph Custom Post Data', 'robotstxt-og' ),
			'callback'             => array( $this, 'erase_privacy_data' ),
		);
		return $erasers;
	}

	/**
	 * Export personal data stored by this plugin for a given email address.
	 *
	 * Exports the custom og:title and og:description stored in post meta for
	 * all posts authored by the user with the given email address.
	 *
	 * @since 1.0.3
	 *
	 * @param string $email_address User email address.
	 * @param int    $page          Pagination page (1-based).
	 * @return array{data: array<int, array<string, mixed>>, done: bool} Export result.
	 */
	public function export_privacy_data( string $email_address, int $page = 1 ): array {
		$user = get_user_by( 'email', $email_address );

		if ( ! $user ) {
			return array(
				'data' => array(),
				'done' => true,
			);
		}

		$posts = get_posts(
			array(
				'author'         => $user->ID,
				'post_type'      => 'any',
				'post_status'    => 'any',
				'posts_per_page' => 100,
				'paged'          => $page,
				'fields'         => 'ids',
			)
		);

		$data = array();

		foreach ( $posts as $post_id ) {
			$og_title = get_post_meta( $post_id, '_og_title', true );
			$og_desc  = get_post_meta( $post_id, '_og_description', true );
			$creator  = get_post_meta( $post_id, '_twitter_creator', true );
			$og_alt   = get_post_meta( $post_id, '_og_image_alt', true );

			if ( empty( $og_title ) && empty( $og_desc ) && empty( $creator ) && empty( $og_alt ) ) {
				continue;
			}

			$item_data = array();

			if ( ! empty( $og_title ) && is_string( $og_title ) ) {
				$item_data[] = array(
					'name'  => __( 'Custom OG Title', 'robotstxt-og' ),
					'value' => $og_title,
				);
			}

			if ( ! empty( $og_desc ) && is_string( $og_desc ) ) {
				$item_data[] = array(
					'name'  => __( 'Custom OG Description', 'robotstxt-og' ),
					'value' => $og_desc,
				);
			}

			if ( ! empty( $creator ) && is_string( $creator ) ) {
				$item_data[] = array(
					'name'  => __( 'Twitter Author Handle', 'robotstxt-og' ),
					'value' => $creator,
				);
			}

			if ( ! empty( $og_alt ) && is_string( $og_alt ) ) {
				$item_data[] = array(
					'name'  => __( 'Custom OG Image Alt', 'robotstxt-og' ),
					'value' => $og_alt,
				);
			}

			if ( ! empty( $item_data ) ) {
				$data[] = array(
					'group_id'    => 'robotstxt-og-post-meta',
					'group_label' => __( 'OpenGraph Post Meta', 'robotstxt-og' ),
					'item_id'     => 'post-' . $post_id,
					'data'        => $item_data,
				);
			}
		}

		$done = count( $posts ) < 100;

		return array(
			'data' => $data,
			'done' => $done,
		);
	}

	/**
	 * Erase personal data stored by this plugin for a given email address.
	 *
	 * Removes custom og:title and og:description from all posts authored by
	 * the user with the given email address.
	 *
	 * @since 1.0.3
	 *
	 * @param string $email_address User email address.
	 * @param int    $page          Pagination page (1-based).
	 * @return array{items_removed: int, items_retained: int, messages: string[], done: bool} Erase result.
	 */
	public function erase_privacy_data( string $email_address, int $page = 1 ): array {
		$user = get_user_by( 'email', $email_address );

		if ( ! $user ) {
			return array(
				'items_removed'  => 0,
				'items_retained' => 0,
				'messages'       => array(),
				'done'           => true,
			);
		}

		$posts = get_posts(
			array(
				'author'         => $user->ID,
				'post_type'      => 'any',
				'post_status'    => 'any',
				'posts_per_page' => 100,
				'paged'          => $page,
				'fields'         => 'ids',
			)
		);

		$items_removed = 0;

		foreach ( $posts as $post_id ) {
			$removed = false;

			foreach ( array( '_og_title', '_og_description', '_twitter_creator', '_og_image_alt' ) as $meta_key ) {
				if ( delete_post_meta( $post_id, $meta_key ) ) {
					$removed = true;
				}
			}

			if ( $removed ) {
				++$items_removed;
			}
		}

		$done = count( $posts ) < 100;

		return array(
			'items_removed'  => $items_removed,
			'items_retained' => 0,
			'messages'       => array(),
			'done'           => $done,
		);
	}

	/**
	 * Get image resolver instance.
	 *
	 * @since 1.0.0
	 *
	 * @return Robotstxt_OG_Image_Resolver
	 */
	public function get_resolver(): Robotstxt_OG_Image_Resolver {
		return $this->resolver;
	}

	/**
	 * Get OG tags generator instance.
	 *
	 * @since 1.0.0
	 *
	 * @return Robotstxt_OG_Tags
	 */
	public function get_tags(): Robotstxt_OG_Tags {
		return $this->tags;
	}
}