<?php
/**
 * REST endpoint that renders a pasted rule's fields for the classic screens.
 *
 * @package Yangra\Conditional
 */

namespace Yangra\Conditional\Rest;

use WP_REST_Request;
use WP_REST_Response;
use WP_REST_Server;
use Yangra\Conditional\Rules\RuleFields;
use Yangra\Conditional\Rules\RuleSanitizer;

defined( 'ABSPATH' ) || exit;

/**
 * POST /wp-json/yangra-conditional/v1/rule-fields
 *
 * "Paste rule" in Appearance → Menus and widget forms sends the copied rule
 * and the rule's field name prefix, and gets back the condition groups' HTML
 * to put in place of the current ones. The fields are rendered on the server
 * so they match RuleFields exactly, picked items get their labels and Pro
 * conditions this build can't check are shown as skipped. Nothing is saved:
 * the menu or widget is saved as usual.
 */
class RuleFieldsController {

	/**
	 * Field names allowed as a prefix: letters, digits, `_`, `-` and brackets,
	 * e.g. "yangra_conditional_rule[12]" or "widget-text[3][yangra_conditional_rule]".
	 */
	const NAME_PATTERN = '/^[A-Za-z0-9_\-\[\]]{1,200}$/';

	/**
	 * Rule fields.
	 *
	 * @var RuleFields
	 */
	private $fields;

	/**
	 * Rule sanitizer.
	 *
	 * @var RuleSanitizer
	 */
	private $sanitizer;

	/**
	 * Constructor.
	 *
	 * @param RuleFields    $fields    Rule fields.
	 * @param RuleSanitizer $sanitizer Rule sanitizer.
	 */
	public function __construct( RuleFields $fields, RuleSanitizer $sanitizer ) {
		$this->fields    = $fields;
		$this->sanitizer = $sanitizer;
	}

	/**
	 * Registers hooks.
	 *
	 * @return void
	 */
	public function register(): void {
		add_action( 'rest_api_init', array( $this, 'register_routes' ) );
	}

	/**
	 * Registers REST routes.
	 *
	 * @return void
	 */
	public function register_routes(): void {
		register_rest_route(
			SettingsController::ROUTE_NAMESPACE,
			'/rule-fields',
			array(
				array(
					'methods'             => WP_REST_Server::CREATABLE,
					'callback'            => array( $this, 'render' ),
					'permission_callback' => array( $this, 'can_edit' ),
					'args'                => array(
						'name' => array(
							'type'     => 'string',
							'required' => true,
							'pattern'  => trim( self::NAME_PATTERN, '/' ),
						),
						'rule' => array(
							'type'     => 'object',
							'required' => true,
						),
					),
				),
			)
		);
	}

	/**
	 * Classic menus and widgets both need `edit_theme_options`.
	 *
	 * @return bool
	 */
	public function can_edit(): bool {
		return current_user_can( 'edit_theme_options' );
	}

	/**
	 * Renders the pasted rule's condition groups. Copied rules have no IDs,
	 * so the sanitizer gives every group and condition a new one.
	 *
	 * @param WP_REST_Request $request Request.
	 * @phpstan-param WP_REST_Request<array<string, mixed>> $request
	 * @return WP_REST_Response
	 */
	public function render( WP_REST_Request $request ): WP_REST_Response {
		$rule = $this->sanitizer->sanitize( $request->get_param( 'rule' ) );

		ob_start();
		$this->fields->render_groups( (string) $request->get_param( 'name' ), $rule['groups'] );

		return new WP_REST_Response(
			array(
				'action' => $rule['action'],
				'groups' => count( $rule['groups'] ),
				'html'   => (string) ob_get_clean(),
			)
		);
	}
}