// Dart 侧验证：把 Symja 通道 mock 掉，检查外壳、计算器按键、控制台命令、工具页。
// 真机端到端验证另做（本构建机没有 KVM，跑不了模拟器）。
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_test/flutter_test.dart';

import 'package:cal/calculator_page.dart';
import 'package:cal/console_page.dart';
import 'package:cal/main.dart';
import 'package:cal/tools_page.dart';

void main() {
  const symja = MethodChannel('com.nonvioce.cal/symja');
  const mcp = MethodChannel('com.nonvioce.cal/mcp');
  final calls = <MethodCall>[];

  setUp(() {
    calls.clear();
    TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger
        .setMockMethodCallHandler(symja, (call) async {
      calls.add(call);
      switch (call.method) {
        case 'evaluate':
          final expr = call.arguments['expr'] as String;
          if (expr == 'boom') {
            return <String, dynamic>{'ok': false, 'error': '模拟的失败'};
          }
          return <String, dynamic>{
            'ok': true,
            'text': 'x^3/3',
            'tex': r'\frac{{x}^{3}}{3}',
            'ms': 12,
          };
        case 'variables':
          return <String, dynamic>{
            'ok': true,
            'vars': [
              {'name': 'a', 'value': '42'},
            ],
          };
        case 'exportSession':
          return <String, dynamic>{'ok': true, 'defs': ['a=42']};
        case 'importSession':
          return <String, dynamic>{'ok': true, 'applied': 1, 'failed': []};
        case 'clearVariable':
        case 'clearAll':
          return <String, dynamic>{'ok': true};
        case 'sample':
          return <String, dynamic>{
            'ok': true,
            'ys': [0.0, 1.0, 0.0],
            'ms': 5,
          };
        case 'cancel':
          return null;
        default:
          return null;
      }
    });
    TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger
        .setMockMethodCallHandler(mcp, (call) async {
      calls.add(call);
      switch (call.method) {
        case 'status':
          return <String, dynamic>{
            'running': false,
            'port': 8734,
            'tools': ['evaluate', 'solve'],
          };
        default:
          return null;
      }
    });
  });

  tearDown(() {
    TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger
        .setMockMethodCallHandler(symja, null);
    TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger
        .setMockMethodCallHandler(mcp, null);
  });

  Future<void> pumpApp(WidgetTester tester) async {
    await tester.pumpWidget(const CalApp());
    await tester.pumpAndSettle();
  }

  Future<void> goTo(WidgetTester tester, String tab) async {
    await tester.tap(find.text(tab));
    await tester.pumpAndSettle();
  }

  /// IndexedStack 会让三个页面同时存在，所以查找必须限定在某一页里。
  Finder inPage(Type page, Finder matching) =>
      find.descendant(of: find.byType(page), matching: matching);

  Future<void> submit(WidgetTester tester, String text) async {
    await tester.enterText(inPage(ConsolePage, find.byType(TextField)), text);
    await tester.testTextInput.receiveAction(TextInputAction.done);
    await tester.pumpAndSettle();
  }

  group('外壳', () {
    testWidgets('三个界面：计算器 / 工具 / 控制台', (tester) async {
      await pumpApp(tester);
      expect(find.text('计算器'), findsWidgets);
      expect(find.text('工具'), findsWidgets);
      expect(find.text('控制台'), findsWidgets);
      // 默认进计算器
      expect(find.byType(CalculatorPage), findsOneWidget);
    });
  });

  group('计算器', () {
    testWidgets('按键把表达式插进显示区，并触发预览', (tester) async {
      await pumpApp(tester);

      await tester.tap(find.text('∫')); // Integrate[□, x] 模板
      await tester.pumpAndSettle();

      final tf = tester.widget<TextField>(
          inPage(CalculatorPage, find.byType(TextField)));
      expect(tf.controller!.text, 'Integrate[, x]');
      // 光标应停在方括号里
      expect(tf.controller!.selection.baseOffset, 'Integrate['.length);
    });

    testWidgets('预览走 preview 标志，不污染 %', (tester) async {
      await pumpApp(tester);
      await tester.enterText(
          inPage(CalculatorPage, find.byType(TextField)), 'Sin[x]');
      // 等防抖
      await tester.pump(const Duration(milliseconds: 700));
      await tester.pumpAndSettle();

      final c = calls.firstWhere((c) => c.method == 'evaluate');
      expect(c.arguments['preview'], true);
    });
  });

  group('控制台', () {
    testWidgets('提交表达式会送到通道并渲染结果', (tester) async {
      await pumpApp(tester);
      await goTo(tester, '控制台');
      await submit(tester, 'Integrate[x^2, x]');

      final eval = calls.lastWhere((c) => c.method == 'evaluate');
      expect(eval.arguments['expr'], 'Integrate[x^2, x]');
      expect(eval.arguments['preview'], false);
      expect(find.text('x^3/3'), findsWidgets);
    });

    testWidgets('help 是本地命令，不求值', (tester) async {
      await pumpApp(tester);
      await goTo(tester, '控制台');
      await submit(tester, 'help');

      expect(calls.where((c) => c.method == 'evaluate' && c.arguments['preview'] == false),
          isEmpty);
      expect(find.textContaining('命令（小写'), findsOneWidget);
    });

    testWidgets('vars 命令列出变量', (tester) async {
      await pumpApp(tester);
      await goTo(tester, '控制台');
      await submit(tester, 'vars');
      expect(find.text('a = 42'), findsOneWidget);
    });

    testWidgets('失败时显示错误', (tester) async {
      await pumpApp(tester);
      await goTo(tester, '控制台');
      await submit(tester, 'boom');
      expect(find.text('模拟的失败'), findsOneWidget);
    });
  });

  group('工具页', () {
    testWidgets('列出插件，并能按名字过滤', (tester) async {
      await pumpApp(tester);
      await goTo(tester, '工具');

      // 网格是懒加载的，靠后的卡片在测试视口外，所以只断言前几个
      expect(find.text('错位相减法'), findsOneWidget);
      expect(find.text('二项分布'), findsOneWidget);

      await tester.enterText(inPage(ToolsPage, find.byType(TextField)), '回归');
      await tester.pumpAndSettle();

      expect(find.text('线性回归'), findsOneWidget);
      expect(find.text('二项分布'), findsNothing);
    });

    testWidgets('拼音首字母也能搜到', (tester) async {
      await pumpApp(tester);
      await goTo(tester, '工具');

      await tester.enterText(inPage(ToolsPage, find.byType(TextField)), 'xxhg');
      await tester.pumpAndSettle();
      expect(find.text('线性回归'), findsOneWidget);
    });
  });
}