<?php
namespace AdvancedAddons;

use WP_REST_Request;

class SelectionBridge {
	/**
	 * Shared Gutenberg/Elementor selection and staged-result storage.
	 *
	 * The free editor bridge posts Gutenberg selections to this controller.
	 * Advanced Addons Pro owns continuous Elementor selection synchronization
	 * and writes validated Elementor payloads to this same shared meta store.
	 */

	const META_KEY  = '_wp_ai_builder_selection';
	const RESULT_KEY = '_wp_ai_builder_selection_result';
	const SELECTION_TTL = 30;
	const RESULT_TTL = 3600;

	public function __construct() {
		add_action( 'rest_api_init', array( $this, 'register_routes' ) );
	}

	public function register_routes() {
		register_rest_route( 'wp-ai-builder/v1', '/selection', array(
			'methods'             => 'POST',
			'permission_callback' => array( Security::class, 'rest_can_edit_request' ),
			'callback' => array( $this, 'save_selection' ),
		) );

		register_rest_route( 'wp-ai-builder/v1', '/selection/ack', array(
			'methods'             => 'POST',
			'permission_callback' => array( Security::class, 'rest_can_edit_request' ),
			'callback'            => array( $this, 'ack_result' ),
		) );

		register_rest_route( 'wp-ai-builder/v1', '/selection', array(
			'methods'             => 'GET',
			'permission_callback' => array( Security::class, 'rest_can_edit_request' ),
			'callback' => array( $this, 'get_selection' ),
		) );
	}

	public function save_selection( WP_REST_Request $request ) {
		$user_id = get_current_user_id();
		$editor = sanitize_key( $request->get_param( 'editor' ) ?: 'gutenberg' );
		$post_id = intval( $request->get_param( 'post_id' ) );
		if ( $post_id > 0 && ! Security::can_edit_post( $post_id ) ) {
			return new \WP_Error(
				'rest_cannot_edit',
				__( 'Sorry, you are not allowed to edit this post.', 'advanced-animation' ),
				array( 'status' => rest_authorization_required_code() )
			);
		}
		if ( $request->get_param( 'clear' ) ) {
			self::clear_selection( $editor, $user_id );
			return rest_ensure_response( array( 'success' => true, 'cleared' => true ) );
		}
		$data    = array(
			'editor'       => $editor,
			'post_id'      => $post_id ?: $request->get_param( 'post_id' ),
			'clientIds'    => $request->get_param( 'clientIds' ),
			'blocks'       => $request->get_param( 'blocks' ),
			'indices'      => $request->get_param( 'indices' ),
			'html'         => $request->get_param( 'html' ),
			'post_content' => $request->get_param( 'post_content' ),
			'elementData'  => $request->get_param( 'elementData' ),
			'selection_token' => sanitize_text_field( $request->get_param( 'selection_token' ) ?: '' ),
			'semantic_version' => class_exists( Gutenberg_Transaction_Service::class )
				? Gutenberg_Transaction_Service::semantic_version( (string) $request->get_param( 'post_content' ) )
				: sanitize_text_field( $request->get_param( 'semantic_version' ) ?: '' ),
			'representation_version' => class_exists( Gutenberg_Transaction_Service::class )
				? Gutenberg_Transaction_Service::representation_version( (string) $request->get_param( 'post_content' ) )
				: sanitize_text_field( $request->get_param( 'representation_version' ) ?: '' ),
			'editor_session_id' => sanitize_text_field( $request->get_param( 'editor_session_id' ) ?: '' ),
			'updated_at'   => time(),
		);
		self::store_selection( $editor, $data, $user_id );
		return rest_ensure_response( array( 'success' => true ) );
	}

	public function get_selection( WP_REST_Request $request ) {
		$user_id   = get_current_user_id();
		$editor    = sanitize_key( $request->get_param( 'editor' ) ?: '' );
		$post_id   = intval( $request->get_param( 'post_id' ) ?: 0 );
		$selection = self::read_selection( $editor ?: null );
		$result    = $editor ? self::read_result( $editor, $post_id, $user_id ) : null;

		if ( 'gutenberg' === $editor ) {
			if ( ! $post_id || intval( $selection['post_id'] ?? 0 ) !== $post_id ) {
				$selection = null;
			}
		}

		return rest_ensure_response( array(
			'selection' => $selection ?: null,
			'result'    => $result ?: null,
		) );
	}

	public function ack_result( WP_REST_Request $request ) {
		$user_id = get_current_user_id();
		$editor  = sanitize_key( $request->get_param( 'editor' ) ?: 'gutenberg' );
		$post_id = intval( $request->get_param( 'post_id' ) ?: 0 );
		if ( 'gutenberg' === $editor && ! $post_id ) {
			return rest_ensure_response( array( 'success' => false, 'code' => 'result_post_missing' ) );
		}
		$result  = self::read_result( $editor, $post_id, $user_id );
		if ( ! $result ) {
			if ( 'gutenberg' === $editor && self::has_gutenberg_results( $user_id ) ) {
				return rest_ensure_response( array( 'success' => false, 'code' => 'result_post_mismatch' ) );
			}
			return rest_ensure_response( array( 'success' => false, 'code' => 'result_missing' ) );
		}
		if ( 'gutenberg' === $editor && intval( $result['post_id'] ?? 0 ) !== $post_id ) {
			return rest_ensure_response( array( 'success' => false, 'code' => 'result_post_mismatch' ) );
		}
		$result_id = sanitize_text_field( $request->get_param( 'result_id' ) ?: '' );
		if ( $result_id && $result_id !== ( $result['result_id'] ?? '' ) ) {
			if ( 'gutenberg' === $editor && self::result_identity_is_for_another_post( $user_id, $post_id, $result_id, '' ) ) {
				return rest_ensure_response( array( 'success' => false, 'code' => 'result_post_mismatch' ) );
			}
			return rest_ensure_response( array( 'success' => false, 'code' => 'result_mismatch' ) );
		}
		$transaction_id = sanitize_text_field( $request->get_param( 'transaction_id' ) ?: '' );
		if ( $transaction_id && $transaction_id !== ( $result['transaction_id'] ?? '' ) ) {
			if ( 'gutenberg' === $editor && self::result_identity_is_for_another_post( $user_id, $post_id, '', $transaction_id ) ) {
				return rest_ensure_response( array( 'success' => false, 'code' => 'result_post_mismatch' ) );
			}
			return rest_ensure_response( array( 'success' => false, 'code' => 'result_mismatch' ) );
		}
		$status = sanitize_key( $request->get_param( 'status' ) ?: 'applied' );
		if ( ! in_array( $status, array( 'applied', 'conflict' ), true ) ) {
			return rest_ensure_response( array( 'success' => false, 'code' => 'ack_status_invalid' ) );
		}
		if ( 'conflict' === $status ) {
			$reason = sanitize_key( $request->get_param( 'reason' ) ?: '' );
			if (
				'gutenberg' !== $editor ||
				! in_array( $reason, array( 'editor_session_changed', 'editor_semantic_changed' ), true )
			) {
				return rest_ensure_response( array( 'success' => false, 'code' => 'conflict_reason_invalid' ) );
			}
			if ( ! $result_id || ( ! empty( $result['transaction_id'] ) && ! $transaction_id ) ) {
				return rest_ensure_response( array( 'success' => false, 'code' => 'result_identity_missing' ) );
			}
			if ( $transaction_id && class_exists( Gutenberg_Transaction_Service::class ) ) {
				$conflict = Gutenberg_Transaction_Service::acknowledge( $transaction_id, array(
					'status' => 'conflict',
					'reason' => $reason,
					'force_conflict' => 'editor_session_changed' === $reason,
					'editor_content' => (string) ( $request->get_param( 'editor_content' ) ?: '' ),
				) );
				if ( is_wp_error( $conflict ) && 'editor_semantic_conflict' !== $conflict->get_error_code() ) {
					return rest_ensure_response( array( 'success' => false, 'code' => $conflict->get_error_code(), 'message' => $conflict->get_error_message() ) );
				}
			}
			self::clear_result( $editor, $post_id, $transaction_id, $result_id, $user_id );
			return rest_ensure_response( array( 'success' => true, 'status' => 'delivery_conflict', 'reason' => $reason ) );
		}
		if ( $transaction_id && class_exists( Gutenberg_Transaction_Service::class ) ) {
			$ack = Gutenberg_Transaction_Service::acknowledge( $transaction_id, array(
				'status' => $status,
				'editor_content' => (string) ( $request->get_param( 'editor_content' ) ?: '' ),
				'semantic_version' => sanitize_text_field( $request->get_param( 'semantic_version' ) ?: '' ),
				'representation_version' => sanitize_text_field( $request->get_param( 'representation_version' ) ?: '' ),
				'tailwind_css' => (string) ( $request->get_param( 'tailwind_css' ) ?: '' ),
				'validation' => $request->get_param( 'validation' ),
			) );
			if ( is_wp_error( $ack ) ) {
				return rest_ensure_response( array( 'success' => false, 'code' => $ack->get_error_code(), 'message' => $ack->get_error_message() ) );
			}
		}
		self::clear_result( $editor, $post_id, $transaction_id, $result_id, $user_id );
		return rest_ensure_response( array( 'success' => true ) );
	}

	/**
	 * Read the current user's stored selection.
	 *
	 * @return array|null Stored selection or null.
	 */
	public static function read_selection( ?string $editor = null ) {
		$user_id   = get_current_user_id();
		$records   = self::read_editor_records( self::META_KEY, $user_id );
		if ( $editor ) {
			return isset( $records[ $editor ] ) && is_array( $records[ $editor ] ) ? $records[ $editor ] : null;
		}
		foreach ( array( 'gutenberg', 'elementor' ) as $candidate ) {
			if ( ! empty( $records[ $candidate ] ) ) {
				return $records[ $candidate ];
			}
		}
		return null;
	}

	public static function store_selection( string $editor, array $data, ?int $user_id = null ): void {
		$user_id = $user_id ?: get_current_user_id();
		$records = self::read_editor_records( self::META_KEY, $user_id );
		$data['editor'] = $editor;
		$data['updated_at'] = $data['updated_at'] ?? time();
		$records[ $editor ] = $data;
		// Metadata APIs unslash values before storage. Preserve serialized block
		// markup and JSON attributes byte-for-byte across snapshot writes.
		update_user_meta( $user_id, self::META_KEY, wp_slash( $records ) );
	}

	/** Remove one editor's selection snapshot without affecting other editors. */
	public static function clear_selection( string $editor, ?int $user_id = null ): void {
		$user_id = $user_id ?: get_current_user_id();
		$records = self::read_editor_records( self::META_KEY, $user_id );
		unset( $records[ $editor ] );
		update_user_meta( $user_id, self::META_KEY, wp_slash( $records ) );
	}

	public static function is_fresh( array $selection ): bool {
		return ! empty( $selection['updated_at'] ) && time() - intval( $selection['updated_at'] ) <= self::SELECTION_TTL;
	}

	/**
	 * Store a result for the JS editor to pick up.
	 *
	 * @param array $result Result data (blocks, indices).
	 */
	public static function store_result( $result ): bool {
		if ( ! is_array( $result ) ) {
			return false;
		}
		$user_id = get_current_user_id();
		if ( is_array( $result ) && empty( $result['editor'] ) ) {
			$result['editor'] = 'gutenberg';
		}
		$editor = sanitize_key( $result['editor'] ?? 'gutenberg' );
		$post_id = intval( $result['post_id'] ?? 0 );
		if ( 'gutenberg' === $editor && ! $post_id ) {
			return false;
		}

		self::track_unsplash_from_result( $result );

		$records = self::read_result_records( $user_id );
		$result['result_id'] = $result['result_id'] ?? wp_generate_uuid4();
		$result['created_at'] = $result['created_at'] ?? time();
		if ( 'gutenberg' === $editor ) {
			$queue = is_array( $records['gutenberg'] ?? null ) ? $records['gutenberg'] : array();
			$queue[ $post_id ] = $result;
			$records['gutenberg'] = $queue;
		} else {
			$records[ $editor ] = $result;
		}
		update_user_meta( $user_id, self::RESULT_KEY, wp_slash( $records ) );
		return true;
	}

	/**
	 * Trigger Unsplash download tracking for images embedded in a staged result.
	 *
	 * @param array $result Staged editor result.
	 */
	private static function track_unsplash_from_result( array $result ): void {
		if ( ! class_exists( \AdvancedAddons\Tools\Search_Unsplash_Image_Tool::class ) ) {
			return;
		}
		$chunks = array(
			(string) ( $result['html'] ?? '' ),
			(string) ( $result['post_content'] ?? '' ),
			(string) ( $result['replacement_html'] ?? '' ),
		);
		\AdvancedAddons\Tools\Search_Unsplash_Image_Tool::track_downloads_in_content( implode( "\n", $chunks ) );
	}

	/** Read one staged result, strictly addressed by post for Gutenberg. */
	public static function read_result( string $editor, int $post_id = 0, ?int $user_id = null ): ?array {
		$user_id = $user_id ?: get_current_user_id();
		$records = self::read_result_records( $user_id );
		if ( 'gutenberg' === $editor ) {
			if ( ! $post_id ) {
				return null;
			}
			$result = $records['gutenberg'][ $post_id ] ?? null;
		} else {
			$result = $records[ $editor ] ?? null;
		}
		if ( ! is_array( $result ) || sanitize_key( $result['editor'] ?? 'gutenberg' ) !== $editor ) {
			return null;
		}
		return $result;
	}

	/** Clear only the exact delivered result; other post queues remain intact. */
	public static function clear_result( string $editor, int $post_id = 0, string $transaction_id = '', string $result_id = '', ?int $user_id = null ): bool {
		$user_id = $user_id ?: get_current_user_id();
		$records = self::read_result_records( $user_id );
		$result = self::read_result( $editor, $post_id, $user_id );
		if ( ! $result ) {
			return false;
		}
		if ( $transaction_id && $transaction_id !== ( $result['transaction_id'] ?? '' ) ) {
			return false;
		}
		if ( $result_id && $result_id !== ( $result['result_id'] ?? '' ) ) {
			return false;
		}
		if ( 'gutenberg' === $editor ) {
			unset( $records['gutenberg'][ $post_id ] );
			if ( empty( $records['gutenberg'] ) ) {
				unset( $records['gutenberg'] );
			}
		} else {
			unset( $records[ $editor ] );
		}
		update_user_meta( $user_id, self::RESULT_KEY, wp_slash( $records ) );
		return true;
	}

	private static function has_gutenberg_results( int $user_id ): bool {
		$records = self::read_result_records( $user_id );
		return ! empty( $records['gutenberg'] );
	}

	private static function result_identity_is_for_another_post( int $user_id, int $post_id, string $result_id, string $transaction_id ): bool {
		$records = self::read_result_records( $user_id );
		foreach ( $records['gutenberg'] ?? array() as $candidate_post_id => $candidate ) {
			if ( intval( $candidate_post_id ) === $post_id || ! is_array( $candidate ) ) {
				continue;
			}
			if ( $result_id && $result_id === ( $candidate['result_id'] ?? '' ) ) {
				return true;
			}
			if ( $transaction_id && $transaction_id === ( $candidate['transaction_id'] ?? '' ) ) {
				return true;
			}
		}
		return false;
	}

	/** Normalize legacy flat Gutenberg results into a post-keyed queue. */
	private static function read_result_records( int $user_id ): array {
		$value = get_user_meta( $user_id, self::RESULT_KEY, true );
		if ( ! is_array( $value ) || empty( $value ) ) {
			return array();
		}
		if ( ! isset( $value['gutenberg'] ) && ! isset( $value['elementor'] ) ) {
			$editor = sanitize_key( $value['editor'] ?? 'gutenberg' );
			$value = array( $editor => $value );
		}

		$changed = false;
		$gutenberg = $value['gutenberg'] ?? array();
		if ( self::is_result_record( $gutenberg ) ) {
			$post_id = intval( $gutenberg['post_id'] ?? 0 );
			$value['gutenberg'] = $post_id ? array( $post_id => $gutenberg ) : array();
			$changed = true;
		}

		if ( isset( $value['gutenberg'] ) && is_array( $value['gutenberg'] ) ) {
			foreach ( $value['gutenberg'] as $post_id => $result ) {
				$created_at = is_array( $result ) ? intval( $result['created_at'] ?? 0 ) : 0;
				if ( ! is_array( $result ) || intval( $result['post_id'] ?? 0 ) !== intval( $post_id ) || ! $created_at || time() - $created_at > self::RESULT_TTL ) {
					unset( $value['gutenberg'][ $post_id ] );
					$changed = true;
				}
			}
			if ( empty( $value['gutenberg'] ) ) {
				unset( $value['gutenberg'] );
				$changed = true;
			}
		}

		if ( $changed ) {
			update_user_meta( $user_id, self::RESULT_KEY, wp_slash( $value ) );
		}
		return $value;
	}

	private static function is_result_record( $value ): bool {
		return is_array( $value ) && ( isset( $value['result_id'] ) || isset( $value['action'] ) || isset( $value['post_id'] ) );
	}

	private static function read_editor_records( string $key, int $user_id ): array {
		$value = get_user_meta( $user_id, $key, true );
		if ( ! is_array( $value ) || empty( $value ) ) {
			return array();
		}
		if ( isset( $value['gutenberg'] ) || isset( $value['elementor'] ) ) {
			return $value;
		}
		$editor = sanitize_key( $value['editor'] ?? 'gutenberg' );
		return array( $editor => $value );
	}
}