import 'dart:async';

import 'package:flutter/foundation.dart';

import 'models.dart';
import 'service.dart';

class BankSearchProvider extends ChangeNotifier {
  BankSearchProvider(this.service);
  final DestinationService service;
  Timer? _timer;
  Completer<void>? _abort;
  int _generation = 0;
  bool _disposed = false, loading = false;
  String query = '';
  List<Bank> results = [];
  DestinationIssue? error;
  void search(String value) {
    _timer?.cancel();
    if (_abort != null && !_abort!.isCompleted) _abort!.complete();
    _abort = null;
    final generation = ++_generation;
    query = value;
    results = [];
    error = null;
    loading = false;
    if (value.trim().length >= 2) {
      _timer = Timer(
        const Duration(milliseconds: 350),
        () => _lookup(value, generation),
      );
    }
    notifyListeners();
  }

  Future<void> _lookup(String value, int generation) async {
    loading = true;
    notifyListeners();
    try {
      final abort = Completer<void>();
      _abort = abort;
      final rows = await service.banks(value, abortTrigger: abort.future);
      if (_disposed || generation != _generation) return;
      results = rows;
      if (rows.isEmpty) error = DestinationIssue.invalid;
    } on DestinationException catch (e) {
      if (!_disposed && generation == _generation) error = e.issue;
    } catch (_) {
      if (!_disposed && generation == _generation)
        error = DestinationIssue.unavailable;
    }
    if (_disposed || generation != _generation) return;
    loading = false;
    notifyListeners();
  }

  @override
  void dispose() {
    _disposed = true;
    _generation++;
    _timer?.cancel();
    if (_abort != null && !_abort!.isCompleted) _abort!.complete();
    super.dispose();
  }
}