import 'dart:async';

import 'package:flutter/foundation.dart';
import 'package:flutter/services.dart';
import 'package:flutter/widgets.dart';
import 'package:go_router/go_router.dart';
import 'package:riverpod_annotation/riverpod_annotation.dart';

part 'url_replacer.g.dart';

/// Replaces the browser URL of the current page without a new history entry
/// and without rebuilding the page (so state, scroll position and focus stay).
///
/// Web only: on other platforms there is no visible URL, nothing happens.
/// The router state is updated inside `Router.neglect` (no history entry from
/// the router), the address bar is replaced with
/// `SystemNavigator.routeInformationUpdated(replace: true)`.
class UrlReplacer {
  const UrlReplacer({this.isWeb = kIsWeb});

  /// Whether to write at all (injectable for tests).
  final bool isWeb;

  void replace(BuildContext context, Uri uri) {
    if (!isWeb) {
      return;
    }
    final router = GoRouter.maybeOf(context);
    if (router != null) {
      final current = router.routeInformationProvider.value.uri;
      if (current != uri) {
        Router.neglect(context, () => router.go(uri.toString()));
      }
    }
    unawaited(SystemNavigator.routeInformationUpdated(uri: uri, replace: true));
  }
}

/// Override in tests.
@Riverpod(keepAlive: true)
UrlReplacer urlReplacer(Ref ref) => const UrlReplacer();