import 'dart:async';

import 'package:flutter/material.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:frontend/core/constants/app_sizes.dart';
import 'package:frontend/core/theme/app_colors.dart';
import 'package:frontend/features/home/data/home_repository.dart';
import 'package:frontend/features/home/data/mock_home_data.dart';
import 'package:frontend/features/home/data/mock_home_repository.dart';
import 'package:frontend/features/home/domain/models/home_data.dart';
import 'package:frontend/features/home/domain/models/submit_site_draft.dart';
import 'package:frontend/features/home/presentation/pages/home_page.dart';
import 'package:frontend/features/home/presentation/widgets/link_card.dart';
import 'package:frontend/features/home/presentation/widgets/link_section_view.dart';
import 'package:frontend/features/home/presentation/widgets/sidebar_nav.dart';

import '../../../helpers/fake_url_opener.dart';

void main() {
  late FakeUrlOpener urlOpener;

  setUp(() {
    urlOpener = FakeUrlOpener();
  });

  Future<void> pumpPage(
    WidgetTester tester, {
    // 高度取 420：原型只有两段内容，视口再高就滚不动了，
    // 「回到顶部」这类用例也就没有意义。
    Size size = const Size(900, 420),
    HomeRepository repository = const MockHomeRepository(),
    /// 加载中的用例要停在第一帧，不能等它 settle。
    bool settle = true,
  }) async {
    tester.view.physicalSize = size;
    tester.view.devicePixelRatio = 1;
    addTearDown(tester.view.reset);

    await tester.pumpWidget(
      MaterialApp(
        home: HomePage(
          repository: repository,
          urlOpener: urlOpener,
        ),
      ),
    );
    // 数据现在来自 Future，等它落地后再断言。
    if (settle) {
      await tester.pumpAndSettle();
    } else {
      await tester.pump();
    }
  }

  /// 侧栏里的导航文字（避免和内容区的分区标题同名而混淆）。
  Finder navText(String label) {
    return find.descendant(
      of: find.byType(SidebarNav),
      matching: find.text(label),
    );
  }

  /// 内容区的分区标题。
  Finder sectionTitle(String label) {
    return find.descendant(
      of: find.byType(LinkSectionView),
      matching: find.text(label),
    );
  }

  double sidebarWidth(WidgetTester tester) {
    return tester.getSize(find.byType(SidebarNav)).width;
  }

  Color? navColor(WidgetTester tester, String label) {
    return tester.widget<Text>(navText(label)).style?.color;
  }

  /// 一级条目当前的底色（透明表示没有高亮）。
  List<String> highlightedRows(WidgetTester tester) {
    final List<String> rows = <String>[];
    for (final String label in <String>['常用推荐', '素材资源', '开发工具']) {
      final AnimatedContainer container = tester.widget<AnimatedContainer>(
        find
            .ancestor(
              of: navText(label),
              matching: find.byType(AnimatedContainer),
            )
            .first,
      );
      final Color? color = (container.decoration! as BoxDecoration).color;
      if (color != null && color.toARGB32() != 0) {
        rows.add(label);
      }
    }
    return rows;
  }

  /// 主内容区的滚动控制器。
  ///
  /// 侧栏的导航容器也是一个 SingleChildScrollView，所以这里用
  /// 「搜索框的祖先」来精确定位主滚动视图，而不是靠 `.first` / `.last`。
  ScrollController mainController(WidgetTester tester) {
    final Finder mainScroll = find.ancestor(
      of: find.byType(TextField),
      matching: find.byType(SingleChildScrollView),
    );
    return tester.widget<SingleChildScrollView>(mainScroll).controller!;
  }

  double scrollOffset(WidgetTester tester) => mainController(tester).offset;

  Future<void> expandMaterials(WidgetTester tester) async {
    await tester.tap(navText('素材资源'));
    await tester.pumpAndSettle();
  }

  /// 折叠态下导航项是空行（没有文字也没有图标），只能按位置定位：
  /// 0 是侧栏本身，1~3 是三条一级导航。
  Finder collapsedRow(int index) {
    return find
        .descendant(
          of: find.byType(SidebarNav),
          matching: find.byType(AnimatedContainer),
        )
        .at(index);
  }

  group('布局', () {
    testWidgets('侧栏展开常驻，渲染 logo、三条导航与底部提交入口', (WidgetTester tester) async {
      await pumpPage(tester);

      expect(find.byType(SidebarNav), findsOneWidget);
      expect(sidebarWidth(tester), AppSizes.sidebarWidth);
      expect(find.text('Suxing Nav'), findsOneWidget);

      expect(navText('常用推荐'), findsOneWidget);
      expect(navText('素材资源'), findsOneWidget);
      expect(navText('开发工具'), findsOneWidget);
      expect(navText('提交网站'), findsOneWidget);
      expect(find.byType(AppBar), findsNothing);
    });

    testWidgets('子菜单默认收起', (WidgetTester tester) async {
      await pumpPage(tester);

      expect(navText('UI 设计'), findsNothing);
      expect(navText('图标库'), findsNothing);
      expect(navText('前端框架'), findsNothing);
    });

    testWidgets('两个分区与五张卡片，与原型一致', (WidgetTester tester) async {
      await pumpPage(tester);

      expect(find.byType(LinkSectionView), findsNWidgets(2));
      expect(find.byType(LinkCard), findsNWidgets(5));
      expect(sectionTitle('常用推荐'), findsOneWidget);
      expect(sectionTitle('素材资源 - UI 设计'), findsOneWidget);
    });
  });

  group('侧栏折叠（对应 #toggleBtn）', () {
    testWidgets('点折叠按钮后宽度变为 64，logo 变成首字', (WidgetTester tester) async {
      await pumpPage(tester);

      await tester.tap(find.byTooltip('展开/折叠侧边栏'));
      await tester.pumpAndSettle();

      expect(sidebarWidth(tester), AppSizes.sidebarCollapsedWidth);
      expect(find.text('Suxing Nav'), findsNothing);
      expect(find.text('S'), findsOneWidget);
      // 折叠态下 .nav-text 与 .submit-text 都被隐藏，只剩空行。
      expect(navText('常用推荐'), findsNothing);
      expect(navText('提交网站'), findsNothing);
    });

    testWidgets('再点一次可以展开回来', (WidgetTester tester) async {
      await pumpPage(tester);

      await tester.tap(find.byTooltip('展开/折叠侧边栏'));
      await tester.pumpAndSettle();
      await tester.tap(find.byTooltip('展开/折叠侧边栏'));
      await tester.pumpAndSettle();

      expect(sidebarWidth(tester), AppSizes.sidebarWidth);
      expect(find.text('Suxing Nav'), findsOneWidget);
    });
  });

  group('分组子菜单（对应 .has-sub 的脚本）', () {
    testWidgets('点击分组展开子菜单，再点收起', (WidgetTester tester) async {
      await pumpPage(tester);

      await expandMaterials(tester);
      expect(navText('UI 设计'), findsOneWidget);
      expect(navText('图标库'), findsOneWidget);
      expect(navText('高清壁纸'), findsOneWidget);

      await tester.tap(navText('素材资源'));
      await tester.pumpAndSettle();
      expect(navText('UI 设计'), findsNothing);
    });

    testWidgets('折叠状态下点分组会先展开侧栏', (WidgetTester tester) async {
      await pumpPage(tester);

      await tester.tap(find.byTooltip('展开/折叠侧边栏'));
      await tester.pumpAndSettle();
      expect(sidebarWidth(tester), AppSizes.sidebarCollapsedWidth);

      await tester.tap(collapsedRow(2));
      await tester.pumpAndSettle();

      expect(sidebarWidth(tester), AppSizes.sidebarWidth);
      expect(navText('UI 设计'), findsOneWidget);
    });
  });

  group('导航与内容', () {
    testWidgets('高亮固定写在第一个条目上', (WidgetTester tester) async {
      await pumpPage(tester);

      expect(navColor(tester, '常用推荐'), AppColors.primary);
      expect(navColor(tester, '素材资源'), AppColors.textSecondary);
      expect(highlightedRows(tester), <String>['常用推荐']);
    });

    testWidgets('点有对应分区的导航会滚过去，高亮不变', (WidgetTester tester) async {
      await pumpPage(tester);

      final double before = scrollOffset(tester);
      await expandMaterials(tester);
      await tester.tap(navText('UI 设计'));
      await tester.pumpAndSettle();

      expect(scrollOffset(tester), greaterThan(before));
      expect(navColor(tester, '常用推荐'), AppColors.primary);
      expect(highlightedRows(tester), <String>['常用推荐']);
    });

    testWidgets('点没有对应分区的导航不会有任何反应', (WidgetTester tester) async {
      await pumpPage(tester);

      await expandMaterials(tester);
      await tester.tap(navText('UI 设计'));
      await tester.pumpAndSettle();
      final double afterScroll = scrollOffset(tester);

      // #icon 在原型里没有对应元素。
      await tester.tap(navText('图标库'));
      await tester.pumpAndSettle();

      expect(scrollOffset(tester), afterScroll);
    });

    testWidgets('搜索框只接收输入，不过滤内容', (WidgetTester tester) async {
      await pumpPage(tester);

      await tester.enterText(find.byType(TextField), 'GitHub');
      await tester.pumpAndSettle();

      expect(find.byType(LinkSectionView), findsNWidgets(2));
      expect(find.byType(LinkCard), findsNWidgets(5));
      expect(
        tester.widget<TextField>(find.byType(TextField)).controller?.text,
        'GitHub',
      );
    });
  });

  group('滚动', () {
    testWidgets('滚动主内容不会重建侧栏，也不会改动高亮', (WidgetTester tester) async {
      await pumpPage(tester);
      final ScrollController controller = mainController(tester);

      AnimatedContainer firstRow() {
        return tester.widget<AnimatedContainer>(
          find
              .ancestor(
                of: navText('常用推荐'),
                matching: find.byType(AnimatedContainer),
              )
              .first,
        );
      }

      final AnimatedContainer beforeScroll = firstRow();

      controller.jumpTo(controller.position.maxScrollExtent);
      await tester.pump();
      await tester.pump(const Duration(milliseconds: 200));

      expect(
        identical(beforeScroll, firstRow()),
        isTrue,
        reason: '滚动主内容时侧栏被重建了',
      );
      expect(highlightedRows(tester), <String>['常用推荐']);
    });

    testWidgets('回到顶部把偏移归零', (WidgetTester tester) async {
      await pumpPage(tester);
      final ScrollController controller = mainController(tester);

      controller.jumpTo(controller.position.maxScrollExtent);
      await tester.pump();
      expect(scrollOffset(tester), greaterThan(0));

      await tester.tap(find.byTooltip('回到顶部'));
      await tester.pumpAndSettle();

      expect(scrollOffset(tester), 0);
    });
  });

  group('其它', () {
    testWidgets('点击卡片交由 UrlOpener 打开对应地址', (WidgetTester tester) async {
      await pumpPage(tester);

      await tester.tap(find.text('GitHub'));
      await tester.pump();

      expect(urlOpener.openedUrls, <String>['https://github.com']);
    });

    testWidgets('点提交网站不会有任何反应', (WidgetTester tester) async {
      await pumpPage(tester);

      await tester.tap(navText('提交网站'));
      await tester.pump();
      await tester.pump(const Duration(milliseconds: 400));

      expect(find.byType(SnackBar), findsNothing);
    });
  });

  group('加载状态', () {
    testWidgets('数据没回来时显示加载提示', (WidgetTester tester) async {
      final _PendingRepository repository = _PendingRepository();
      await pumpPage(tester, repository: repository, settle: false);

      expect(find.text('正在加载…'), findsOneWidget);
      expect(find.byType(LinkSectionView), findsNothing);

      repository.completer.complete(mockHomeData);
      await tester.pumpAndSettle();

      expect(find.text('正在加载…'), findsNothing);
      expect(find.byType(LinkSectionView), findsNWidgets(2));
    });

    testWidgets('取数失败时显示原因和重试按钮', (WidgetTester tester) async {
      await pumpPage(
        tester,
        repository: const _FailingRepository('连不上后端（http://127.0.0.1:8080）'),
      );

      expect(find.text('加载失败'), findsOneWidget);
      expect(find.textContaining('连不上后端'), findsOneWidget);
      expect(find.text('重试'), findsOneWidget);
      expect(find.byType(LinkSectionView), findsNothing);
    });

    testWidgets('点重试会重新取数，成功后渲染内容', (WidgetTester tester) async {
      final _FlakyRepository repository = _FlakyRepository();
      await pumpPage(tester, repository: repository);

      expect(find.text('加载失败'), findsOneWidget);

      await tester.tap(find.text('重试'));
      await tester.pumpAndSettle();

      expect(repository.calls, 2);
      expect(find.text('加载失败'), findsNothing);
      expect(find.byType(LinkSectionView), findsNWidgets(2));
      expect(find.byType(LinkCard), findsNWidgets(5));
    });
  });

  group('提交网站', () {
    testWidgets('点侧栏底部按钮跳到后端配的提交入口', (WidgetTester tester) async {
      await pumpPage(tester);

      await tester.tap(navText('提交网站'));
      await tester.pump();

      // 地址来自后端 `site.submitUrl`，页面不再自己弹表单。
      expect(urlOpener.openedUrls, <String>['https://mattermost.example.com']);
    });
  });
}

/// 数据一直不回来，用来测加载中的那一帧。
class _PendingRepository implements HomeRepository {
  final Completer<HomeData> completer = Completer<HomeData>();

  @override
  Future<HomeData> fetchHomeData() => completer.future;

  @override
  Future<void> submitSite(SubmitSiteDraft draft) async {}

  @override
  Future<void> updateSite(String id, SubmitSiteDraft draft) async {}

  @override
  Future<void> deleteSite(String id) async {}
}

/// 永远失败。
class _FailingRepository implements HomeRepository {
  const _FailingRepository(this.message);

  final String message;

  @override
  Future<HomeData> fetchHomeData() async => throw HomeFailure(message);

  @override
  Future<void> submitSite(SubmitSiteDraft draft) async {}

  @override
  Future<void> updateSite(String id, SubmitSiteDraft draft) async {}

  @override
  Future<void> deleteSite(String id) async {}
}

/// 第一次失败、第二次成功，用来验证重试按钮真的重新取数。
class _FlakyRepository implements HomeRepository {
  int calls = 0;

  @override
  Future<HomeData> fetchHomeData() async {
    calls++;
    if (calls == 1) {
      throw const HomeFailure('后端没起来');
    }
    return mockHomeData;
  }

  @override
  Future<void> submitSite(SubmitSiteDraft draft) async {}

  @override
  Future<void> updateSite(String id, SubmitSiteDraft draft) async {}

  @override
  Future<void> deleteSite(String id) async {}
}