nj/app/test/features/editor/widgets/handwriting_canvas_test.dart

// HandwritingCanvas Widget 集成测试 — 指针事件驱动笔画完成回调
//
// 验证：
// 1. Widget 正确渲染（双层 CustomPaint）
// 2. 手势事件触发 onStrokeCompleted 回调
// 3. 不同画笔类型/颜色/宽度正确传递
// 4. 去抖过滤（微小移动被丢弃）

import 'package:flutter/material.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:nuanji_app/features/editor/widgets/handwriting_canvas.dart';
import 'package:nuanji_app/features/editor/widgets/stroke_model.dart';

void main() {
  // ============================================================
  // 辅助
  // ============================================================

  /// 包裹 HandwritingCanvas 在必要的父组件中，提供约束尺寸
  Widget buildTestSubject({
    Key? key,
    BrushType brushType = BrushType.pen,
    String brushColor = '#2D2420',
    double brushWidth = 3.0,
    List<Stroke> strokes = const [],
    ValueChanged<Stroke>? onStrokeCompleted,
  }) {
    return MaterialApp(
      home: Scaffold(
        body: SizedBox(
          width: 800,
          height: 600,
          child: HandwritingCanvas(
            key: key,
            brushType: brushType,
            brushColor: brushColor,
            brushWidth: brushWidth,
            strokes: strokes,
            onStrokeCompleted: onStrokeCompleted,
          ),
        ),
      ),
    );
  }

  /// 使用标准 TestGesture 模拟一条完整的拖拽手势
  Future<void> simulateDragStroke(
    WidgetTester tester,
    List<Offset> points,
  ) async {
    assert(points.length >= 2, '至少需要 down 和 up 两个点');

    final gesture = await tester.startGesture(points.first);
    await tester.pump();

    for (var i = 1; i < points.length; i++) {
      await gesture.moveTo(points[i]);
      await tester.pump();
    }

    await gesture.up();
    await tester.pump();
  }

  // ============================================================
  // 渲染结构验证
  // ============================================================
  group('HandwritingCanvas — 渲染结构', () {
    testWidgets('正确渲染双层 CustomPaint', (tester) async {
      await tester.pumpWidget(buildTestSubject());
      await tester.pumpAndSettle();

      // 应找到 CustomPaint（两层：CachedStrokesPainter + ActiveStrokePainter）
      final customPaints = find.byType(CustomPaint);
      expect(customPaints, findsAtLeast(2));

      // 应找到 Listener（HandwritingCanvas 的 Listener + Gesture 识别器可能有额外 Listener）
      expect(find.byType(Listener), findsAtLeast(1));

      // 应找到 RepaintBoundary（MaterialApp/Scaffold 可能添加额外的）
      expect(find.byType(RepaintBoundary), findsAtLeast(1));
    });

    testWidgets('初始无笔画时仍正确渲染', (tester) async {
      await tester.pumpWidget(buildTestSubject());
      await tester.pumpAndSettle();

      expect(find.byType(HandwritingCanvas), findsOneWidget);
    });
  });

  // ============================================================
  // 手势事件 → onStrokeCompleted
  // ============================================================
  group('HandwritingCanvas — 笔画完成回调', () {
    testWidgets('有效拖拽触发 onStrokeCompleted', (tester) async {
      Stroke? completedStroke;
      await tester.pumpWidget(buildTestSubject(
        onStrokeCompleted: (stroke) => completedStroke = stroke,
      ));
      await tester.pumpAndSettle();

      // 模拟 5 个点的笔画（距离足够大，避免去抖过滤）
      await simulateDragStroke(tester, [
        const Offset(100, 100),
        const Offset(150, 120),
        const Offset(200, 140),
        const Offset(250, 160),
        const Offset(300, 180),
      ]);

      // 应触发回调
      expect(completedStroke, isNotNull);
      expect(completedStroke!.points.length, greaterThanOrEqualTo(2));
      expect(completedStroke!.brushType, BrushType.pen);
      expect(completedStroke!.color, '#2D2420');
      expect(completedStroke!.width, 3.0);
    });

    testWidgets('笔画携带正确的画笔类型', (tester) async {
      Stroke? completedStroke;
      await tester.pumpWidget(buildTestSubject(
        brushType: BrushType.marker,
        onStrokeCompleted: (stroke) => completedStroke = stroke,
      ));
      await tester.pumpAndSettle();

      await simulateDragStroke(tester, [
        const Offset(100, 100),
        const Offset(200, 200),
        const Offset(300, 100),
      ]);

      expect(completedStroke, isNotNull);
      expect(completedStroke!.brushType, BrushType.marker);
    });

    testWidgets('笔画携带正确的颜色和宽度', (tester) async {
      Stroke? completedStroke;
      await tester.pumpWidget(buildTestSubject(
        brushColor: '#E07A5F',
        brushWidth: 8.0,
        onStrokeCompleted: (stroke) => completedStroke = stroke,
      ));
      await tester.pumpAndSettle();

      await simulateDragStroke(tester, [
        const Offset(50, 50),
        const Offset(150, 150),
        const Offset(250, 50),
      ]);

      expect(completedStroke!.color, '#E07A5F');
      expect(completedStroke!.width, 8.0);
    });

    testWidgets('tap（无拖拽）不触发回调', (tester) async {
      Stroke? completedStroke;
      await tester.pumpWidget(buildTestSubject(
        onStrokeCompleted: (stroke) => completedStroke = stroke,
      ));
      await tester.pumpAndSettle();

      // 仅 tap（down + up 在同一位置）— 单点不足以构成笔画
      await tester.tapAt(const Offset(100, 100));
      await tester.pumpAndSettle();

      // Tap 产生 1 个点（down 和 up 位置相同），不触发回调
      expect(completedStroke, isNull);
    });
  });

  // ============================================================
  // 预加载笔画
  // ============================================================
  group('HandwritingCanvas — 预加载笔画', () {
    testWidgets('初始笔画列表正确传入', (tester) async {
      final existingStrokes = [
        Stroke(
          id: 'existing-1',
          points: [
            const StrokePoint(x: 10, y: 10),
            const StrokePoint(x: 100, y: 100),
          ],
        ),
      ];

      await tester.pumpWidget(buildTestSubject(
        strokes: existingStrokes,
      ));
      await tester.pumpAndSettle();

      expect(find.byType(HandwritingCanvas), findsOneWidget);
    });

    testWidgets('笔画更新触发 didUpdateWidget', (tester) async {
      final key = GlobalKey();

      // 第一次渲染 — 无笔画
      await tester.pumpWidget(MaterialApp(
        home: Scaffold(
          body: SizedBox(
            width: 800,
            height: 600,
            child: HandwritingCanvas(
              key: key,
              strokes: const [],
            ),
          ),
        ),
      ));
      await tester.pumpAndSettle();

      // 更新 — 添加笔画
      final updatedStrokes = [
        Stroke(
          id: 'new-1',
          points: [
            const StrokePoint(x: 50, y: 50),
            const StrokePoint(x: 200, y: 200),
          ],
        ),
      ];

      await tester.pumpWidget(MaterialApp(
        home: Scaffold(
          body: SizedBox(
            width: 800,
            height: 600,
            child: HandwritingCanvas(
              key: key,
              strokes: updatedStrokes,
            ),
          ),
        ),
      ));
      await tester.pumpAndSettle();

      expect(find.byType(HandwritingCanvas), findsOneWidget);
    });
  });

  // ============================================================
  // 连续多笔画
  // ============================================================
  group('HandwritingCanvas — 连续多笔画', () {
    testWidgets('连续绘制多条笔画，每条都触发回调', (tester) async {
      final completedStrokes = <Stroke>[];
      await tester.pumpWidget(buildTestSubject(
        onStrokeCompleted: (stroke) => completedStrokes.add(stroke),
      ));
      await tester.pumpAndSettle();

      // 第一条笔画
      await simulateDragStroke(tester, [
        const Offset(50, 50),
        const Offset(150, 100),
        const Offset(250, 50),
      ]);

      // 第二条笔画（使用新的 gesture）
      await simulateDragStroke(tester, [
        const Offset(100, 200),
        const Offset(200, 300),
        const Offset(300, 200),
      ]);

      expect(completedStrokes.length, 2);
      expect(completedStrokes[0].id, isNot(equals(completedStrokes[1].id)));
    });
  });
}