<?php
/**
 * REST endpoints consumed by the Gutenberg sidebar.
 *
 * @package AdaraTranslate
 */

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

final class Adara_Translate_REST {

	public const NAMESPACE = 'adara-translate/v1';

	private static ?self $instance = null;

	public static function instance() : self {
		if ( null === self::$instance ) {
			self::$instance = new self();
		}
		return self::$instance;
	}

	private function __construct() {
		add_action( 'rest_api_init', [ $this, 'register_routes' ] );
	}

	public function register_routes() : void {
		register_rest_route(
			self::NAMESPACE,
			'/translate-post',
			[
				'methods'             => WP_REST_Server::CREATABLE,
				'callback'            => [ $this, 'handle_translate_post' ],
				'permission_callback' => [ $this, 'check_permission' ],
				'args'                => [
					'postId'     => [
						'required'          => true,
						'type'              => 'integer',
						'sanitize_callback' => 'absint',
						'validate_callback' => function ( $value ) {
							return is_numeric( $value ) && (int) $value > 0;
						},
					],
					'targetLang' => [
						'required'          => true,
						'type'              => 'string',
						'sanitize_callback' => 'sanitize_text_field',
						'validate_callback' => [ $this, 'validate_lang_required' ],
					],
					'sourceLang' => [
						'required'          => false,
						'type'              => 'string',
						'sanitize_callback' => 'sanitize_text_field',
						'validate_callback' => [ $this, 'validate_lang_optional' ],
					],
				],
			]
		);
	}

	public function validate_lang_required( $value, $request, $param ) {
		if ( ! is_string( $value ) || ! Adara_Translate_Languages::is_supported( $value ) ) {
			return new WP_Error(
				'rest_invalid_param',
				/* translators: %s: name of the REST parameter (targetLang or sourceLang) */
				sprintf( __( '%s must be a supported language code.', 'adara-translate' ), $param ),
				[ 'status' => 400 ]
			);
		}
		return true;
	}

	public function validate_lang_optional( $value, $request, $param ) {
		if ( null === $value || '' === $value ) {
			return true;
		}
		return $this->validate_lang_required( $value, $request, $param );
	}

	public function check_permission( WP_REST_Request $request ) {
		$post_id = (int) $request->get_param( 'postId' );
		if ( ! $post_id || ! current_user_can( 'edit_post', $post_id ) ) {
			return new WP_Error(
				'rest_forbidden',
				__( 'You do not have permission to translate this post.', 'adara-translate' ),
				[ 'status' => 403 ]
			);
		}
		return true;
	}

	public function handle_translate_post( WP_REST_Request $request ) {
		$post_id     = (int) $request->get_param( 'postId' );
		$target_lang = (string) $request->get_param( 'targetLang' );
		$source_lang = $request->get_param( 'sourceLang' );

		$result = Adara_Translate_Translator::translate_post(
			$post_id,
			$target_lang,
			( is_string( $source_lang ) && '' !== $source_lang ) ? $source_lang : null
		);

		if ( is_wp_error( $result ) ) {
			$data   = $result->get_error_data();
			$status = is_array( $data ) && isset( $data['status'] ) ? (int) $data['status'] : 500;
			return new WP_REST_Response(
				[
					'code'    => $result->get_error_code(),
					'message' => $result->get_error_message(),
					'data'    => is_array( $data ) ? $data : null,
				],
				$status
			);
		}

		return new WP_REST_Response( $result, 201 );
	}
}