<?php
declare(strict_types=1);

namespace WebCalendar\WP\Admin;

defined( 'ABSPATH' ) || exit;

use WebCalendar\Core\Application\DTO\ImportResult;

/**
 * Reports an imported UID that another user already holds as skipped.
 *
 * Core treats UIDs as unique per creator, so it no longer skips a UID that
 * belongs to someone else: it tries to insert the event. This plugin's
 * schema keeps cal_uid UNIQUE, so that insert fails and core reports it as
 * a failed import carrying the raw duplicate-key SQL error. The event is not
 * imported either way; this turns those warnings back into the skip they
 * are, with a message a site owner can act on.
 */
final class ImportUidCollisions {

	/**
	 * Duplicate-key errors: SQLSTATE 23000 from MySQL/MariaDB, and SQLite's
	 * wording for the test database.
	 */
	private const DUPLICATE_KEY = '/SQLSTATE\[23000\]|Duplicate entry|UNIQUE constraint failed/';

	/**
	 * Returns the result with UID collisions counted as skipped.
	 *
	 * @param ImportResult $result Result from ImportService::importIcal().
	 * @return ImportResult
	 */
	public static function fold( ImportResult $result ): ImportResult {
		$warnings  = [];
		$collision = 0;
		foreach ( $result->warnings as $warning ) {
			$message = $warning['message'];
			if (
				preg_match( '/^Failed to import event (.+?): /s', $message, $match ) === 1
				&& preg_match( self::DUPLICATE_KEY, $message ) === 1
			) {
				++$collision;
				$warnings[] = [
					'line'    => $warning['line'],
					'message' => sprintf(
						// translators: %s is the event's iCalendar UID.
						__( 'Skipped event %s: its UID belongs to another calendar.', 'agenticdaisy-calendar' ),
						$match[1]
					),
				];
				continue;
			}
			$warnings[] = $warning;
		}

		if ( 0 === $collision ) {
			return $result;
		}

		return new ImportResult(
			$result->importedCount,
			$result->skippedCount + $collision,
			$warnings,
			$result->updatedCount
		);
	}
}