<?php
/**
 * Gutenberg block editor integration.
 *
 * Registers a Schema AI sidebar panel block for the Gutenberg editor,
 * enqueues the block editor JavaScript bundle, provides a server-side
 * render callback, and registers post meta for REST API access so that
 * the React-based editor panel can read and write schema data.
 *
 * @package    Schema_AI
 * @subpackage Schema_AI/includes/integrations
 * @since      1.0.0
 */

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Class Schema_AI_Gutenberg
 */
class Schema_AI_Gutenberg {

	/**
	 * Register blocks and related hooks.
	 *
	 * Called on the 'init' action. Registers the ai-schema-gen/schema-panel
	 * block type, enqueues block editor assets, and registers post meta.
	 */
	public function register_blocks() {
		// Only proceed if the block editor functions are available.
		if ( ! function_exists( 'register_block_type' ) ) {
			return;
		}

		// Register the Schema AI panel block.
		register_block_type(
			'ai-schema-gen/schema-panel',
			array(
				'api_version'     => 2,
				'editor_script'   => 'ai-schema-gen-block-editor',
				'render_callback' => array( $this, 'render_block' ),
				'attributes'      => array(
					'postId' => array(
						'type'    => 'number',
						'default' => 0,
					),
				),
			)
		);

		// Enqueue block editor assets.
		add_action( 'enqueue_block_editor_assets', array( $this, 'enqueue_block_editor_assets' ) );

		// Register post meta for REST API access.
		$this->register_block_meta();
	}

	/**
	 * Enqueue JavaScript and CSS for the block editor.
	 *
	 * Loads the Schema AI block editor bundle and localises it with
	 * REST URL, nonce, and current post ID so the React sidebar panel
	 * can communicate with the Schema AI REST API.
	 */
	public function enqueue_block_editor_assets() {
		$asset_file = SCHEMA_AI_PLUGIN_DIR . 'admin/js/build/block-editor.asset.php';
		$deps       = array( 'wp-plugins', 'wp-edit-post', 'wp-element', 'wp-components', 'wp-data', 'wp-api-fetch', 'wp-i18n' );
		$version    = SCHEMA_AI_VERSION;

		// Use the generated asset file if it exists (from wp-scripts build).
		if ( file_exists( $asset_file ) ) {
			$asset   = require $asset_file;
			$deps    = isset( $asset['dependencies'] ) ? $asset['dependencies'] : $deps;
			$version = isset( $asset['version'] ) ? $asset['version'] : $version;
		}

		$script_url = SCHEMA_AI_PLUGIN_URL . 'admin/js/build/block-editor.js';

		// Fall back to non-build path if build does not exist.
		if ( ! file_exists( SCHEMA_AI_PLUGIN_DIR . 'admin/js/build/block-editor.js' ) ) {
			$script_url = SCHEMA_AI_PLUGIN_URL . 'admin/js/ai-schema-gen-block-editor.js';
		}

		wp_enqueue_script(
			'ai-schema-gen-block-editor',
			$script_url,
			$deps,
			$version,
			true
		);

		// Localise script with data the React app needs.
		$post_id = 0;
		if ( function_exists( 'get_the_ID' ) ) {
			$post_id = get_the_ID();
		}

		// If get_the_ID() did not work (common in block editor context), try the global post.
		if ( ! $post_id ) {
			global $post;
			if ( isset( $post->ID ) ) {
				$post_id = $post->ID;
			}
		}

		wp_localize_script(
			'ai-schema-gen-block-editor',
			'schemaAiBlock',
			array(
				'restUrl'   => esc_url_raw( rest_url( 'ai-schema-gen/v1/' ) ),
				'nonce'     => wp_create_nonce( 'wp_rest' ),
				'postId'    => absint( $post_id ),
				'pluginUrl' => SCHEMA_AI_PLUGIN_URL,
				'version'   => SCHEMA_AI_VERSION,
			)
		);

		// Enqueue editor styles.
		$style_url = SCHEMA_AI_PLUGIN_URL . 'admin/css/ai-schema-gen-block-editor.css';
		if ( file_exists( SCHEMA_AI_PLUGIN_DIR . 'admin/css/ai-schema-gen-block-editor.css' ) ) {
			wp_enqueue_style(
				'ai-schema-gen-block-editor',
				$style_url,
				array(),
				SCHEMA_AI_VERSION
			);
		}
	}

	/**
	 * Server-side render callback for the ai-schema-gen/schema-panel block.
	 *
	 * Outputs a container div that the React application will hydrate
	 * with the interactive Schema AI panel.
	 *
	 * @param array $attributes Block attributes.
	 * @return string Rendered HTML.
	 */
	public function render_block( $attributes ) {
		$post_id = 0;

		if ( ! empty( $attributes['postId'] ) ) {
			$post_id = absint( $attributes['postId'] );
		}

		if ( ! $post_id ) {
			$post_id = get_the_ID();
		}

		$data_attrs = sprintf(
			'data-post-id="%d" data-rest-url="%s" data-nonce="%s"',
			absint( $post_id ),
			esc_attr( rest_url( 'ai-schema-gen/v1/' ) ),
			esc_attr( wp_create_nonce( 'wp_rest' ) )
		);

		return sprintf(
			'<div id="ai-schema-gen-gutenberg-panel" class="ai-schema-gen-gutenberg-panel" %s></div>',
			$data_attrs
		);
	}

	/**
	 * Register post meta for schema data accessible via the REST API.
	 *
	 * Registers 'schema_ai_schema_data' as a post meta field on all post
	 * types so that the block editor can read and update schema data
	 * through the standard WordPress REST API.
	 */
	public function register_block_meta() {
		register_post_meta(
			'',
			'schema_ai_schema_data',
			array(
				'show_in_rest'  => true,
				'single'        => true,
				'type'          => 'string',
				'default'       => '',
				'auth_callback' => function () {
					return current_user_can( 'edit_posts' );
				},
				'sanitize_callback' => function ( $value ) {
					// Validate that the value is valid JSON if not empty.
					if ( empty( $value ) ) {
						return '';
					}

					$decoded = json_decode( $value, true );
					if ( null === $decoded && JSON_ERROR_NONE !== json_last_error() ) {
						return '';
					}

					return wp_unslash( $value );
				},
			)
		);

		register_post_meta(
			'',
			'schema_ai_schema_type',
			array(
				'show_in_rest'      => true,
				'single'            => true,
				'type'              => 'string',
				'default'           => '',
				'auth_callback'     => function () {
					return current_user_can( 'edit_posts' );
				},
				'sanitize_callback' => 'sanitize_text_field',
			)
		);

		register_post_meta(
			'',
			'schema_ai_auto_generate',
			array(
				'show_in_rest'      => true,
				'single'            => true,
				'type'              => 'boolean',
				'default'           => false,
				'auth_callback'     => function () {
					return current_user_can( 'edit_posts' );
				},
			)
		);
	}
}