import 'dart:async';

import 'package:flutter_test/flutter_test.dart';
import 'package:kooltap/models/bar_tab.dart';
import 'package:kooltap/models/payment_method.dart';
import 'package:kooltap/models/tab_item.dart';
import 'package:kooltap/services/bar_tab_service.dart';
import 'package:kooltap/viewmodels/bar_screen_view_model.dart';
import 'package:mocktail/mocktail.dart';

class MockBarTabService extends Mock implements BarTabService {}

BarTab _tab(String id, {int drinks = 0}) {
  return BarTab(
    id: id,
    customerName: id,
    openedAt: DateTime(2026),
    items: [
      if (drinks > 0)
        TabItem(
          id: '$id-item',
          tabId: id,
          productId: 'prod-1',
          productName: 'Beer',
          quantity: drinks,
          unitPriceInCents: 400,
        ),
    ],
  );
}

void main() {
  late MockBarTabService barTabService;
  late StreamController<List<BarTab>> openTabs;
  late BarScreenViewModel viewModel;

  setUp(() {
    barTabService = MockBarTabService();
    openTabs = StreamController<List<BarTab>>.broadcast();
    when(
      () => barTabService.watchOpenTabs(),
    ).thenAnswer((_) => openTabs.stream);

    viewModel = BarScreenViewModel(barTabService: barTabService);
  });

  tearDown(() async {
    viewModel.dispose();
    await openTabs.close();
  });

  test('starts with no open tabs and nothing selected', () async {
    viewModel.ensureLoaded();
    expect(viewModel.isLoading, true);

    openTabs.add([_tab('a'), _tab('b')]);
    await pumpEventQueue();

    expect(viewModel.isLoading, false);
    expect(viewModel.tabs, isEmpty);
    expect(viewModel.closedTabs.map((tab) => tab.id), ['a', 'b']);
    expect(viewModel.selectedTabId, isNull);
  });

  test('tabs with drinks on them are open', () async {
    viewModel.ensureLoaded();
    openTabs.add([_tab('a', drinks: 2), _tab('b')]);
    await pumpEventQueue();

    expect(viewModel.tabs.map((tab) => tab.id), ['a']);
    expect(viewModel.closedTabs.map((tab) => tab.id), ['b']);
  });

  test('opening a tab shows and selects it', () async {
    viewModel.ensureLoaded();
    openTabs.add([_tab('a'), _tab('b')]);
    await pumpEventQueue();

    viewModel.openTab('b');
    viewModel.deselectTab();

    expect(viewModel.tabs.map((tab) => tab.id), ['b']);
    expect(viewModel.closedTabs.map((tab) => tab.id), ['a']);
  });

  test('a tab settled elsewhere goes back to the closed tabs', () async {
    viewModel.ensureLoaded();
    openTabs.add([_tab('a', drinks: 2)]);
    await pumpEventQueue();
    viewModel.openTab('a');
    viewModel.deselectTab();

    openTabs.add([_tab('a')]);
    await pumpEventQueue();

    expect(viewModel.tabs, isEmpty);
    expect(viewModel.closedTabs.map((tab) => tab.id), ['a']);
  });

  test('closing the selected tab moves it back and deselects', () async {
    when(
      () => barTabService.closeTab(
        'a',
        paymentMethod: PaymentMethod.cash,
      ),
    ).thenAnswer((_) async {});
    viewModel.ensureLoaded();
    openTabs.add([_tab('a'), _tab('b')]);
    await pumpEventQueue();
    viewModel.openTab('a');

    await viewModel.closeSelectedTab();

    expect(viewModel.selectedTabId, isNull);
    expect(viewModel.tabs, isEmpty);
  });

  test('keeps the selection while that tab still exists', () async {
    viewModel.ensureLoaded();
    openTabs.add([_tab('a'), _tab('b')]);
    await pumpEventQueue();
    viewModel.selectTab('b');

    openTabs.add([_tab('c'), _tab('b')]);
    await pumpEventQueue();

    expect(viewModel.selectedTabId, 'b');
  });

  test('selects nothing when the selected tab disappears', () async {
    viewModel.ensureLoaded();
    openTabs.add([_tab('a'), _tab('b')]);
    await pumpEventQueue();
    viewModel.selectTab('b');

    openTabs.add([_tab('a')]);
    await pumpEventQueue();

    expect(viewModel.selectedTabId, isNull);
  });

  test('exposes a load error when the stream fails', () async {
    viewModel.ensureLoaded();
    openTabs.addError(StateError('database closed'));
    await pumpEventQueue();

    expect(viewModel.loadError, isNotNull);
    expect(viewModel.isLoading, false);
  });

  test('propagates an error from the transaction', () async {
    const item = TabItem(
      id: 'item-1',
      tabId: 'tab-1',
      productId: 'prod-1',
      productName: 'Chips',
      quantity: 20,
      unitPriceInCents: 150,
    );

    when(
      () => barTabService.adjustTabItemQuantity(
        tabItemId: 'item-1',
        delta: 1,
        order: any(named: 'order'),
      ),
    ).thenAnswer((_) async => throw const TabNotFoundException('tab-1'));

    await expectLater(
      viewModel.changeItemQuantity(item, 1, null),
      throwsA(isA<TabNotFoundException>()),
    );

    expect(viewModel.loadError, isNull);
  });

  test('selects a newly created tab', () async {
    when(
      () => barTabService.createTab(customerName: 'New', email: null),
    ).thenAnswer((_) async => _tab('new'));

    await viewModel.createTab('New');

    expect(viewModel.selectedTabId, 'new');
  });

  test(
    'rethrows failed actions without turning them into a load error',
    () async {
      when(
        () => barTabService.deleteTab('tab-1'),
      ).thenAnswer((_) async => throw StateError('boom'));

      await expectLater(viewModel.deleteTab('tab-1'), throwsStateError);

      expect(viewModel.loadError, isNull);
    },
  );

  test('finds an open tab by name, ignoring case and spaces', () async {
    viewModel.ensureLoaded();
    openTabs.add([_tab('Jan'), _tab('Piet')]);
    await pumpEventQueue();

    expect(viewModel.hasOpenTabNamed(' jan '), true);
    expect(viewModel.hasOpenTabNamed('Jan', exceptTabId: 'Jan'), false);
    expect(viewModel.hasOpenTabNamed('Joris'), false);
  });
}