// StrokeRasterCache 单元测试 — 光栅化缓存管理器
//
// 注意：ui.PictureRecorder().endRecording().toImage() 需要 Flutter Test 绑定，
// 因此这些测试在 flutter test 环境中运行（自动提供 TestWidgetsFlutterBinding）。
// 使用足够大的画布尺寸（>0）才能使光栅化生效。

import 'dart:ui';

import 'package:flutter_test/flutter_test.dart';
import 'package:nuanji_app/features/editor/widgets/stroke_cache.dart';
import 'package:nuanji_app/features/editor/widgets/stroke_model.dart';

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

  /// 构造一条从 (x0,y0) 到 (x1,y1) 的简单笔画
  Stroke makeStroke(
    String id, {
    double x0 = 10.0,
    double y0 = 10.0,
    double x1 = 200.0,
    double y1 = 200.0,
    BrushType brushType = BrushType.pen,
    String color = '#2D2420',
    double width = 3.0,
    int pointCount = 10,
  }) {
    return Stroke(
      id: id,
      points: List.generate(
        pointCount,
        (i) {
          final t = i / (pointCount - 1);
          return StrokePoint(
            x: x0 + (x1 - x0) * t,
            y: y0 + (y1 - y0) * t,
            pressure: 0.5,
            timestamp: i * 16,
          );
        },
      ),
      brushType: brushType,
      color: color,
      width: width,
    );
  }

  // ============================================================
  // 生命周期与基本属性
  // ============================================================
  group('StrokeRasterCache — 生命周期', () {
    test('初始状态为空', () {
      final cache = StrokeRasterCache();
      addTearDown(cache.dispose);

      expect(cache.compositeImage, isNull);
      expect(cache.layerVersion, 0);
      expect(cache.length, 0);
      expect(cache.cachedStrokeIds, isEmpty);
    });

    test('dispose 后可安全调用', () {
      final cache = StrokeRasterCache();
      cache.dispose();
      // 不应抛异常
      expect(cache.compositeImage, isNull);
    });
  });

  // ============================================================
  // 尺寸管理
  // ============================================================
  group('StrokeRasterCache — 尺寸管理', () {
    test('ensureSize 设置画布尺寸', () {
      final cache = StrokeRasterCache();
      addTearDown(cache.dispose);

      cache.ensureSize(const Size(800, 600));
      expect(cache.canvasSize, const Size(800, 600));
    });

    test('ensureSize 相同尺寸不触发失效', () {
      final cache = StrokeRasterCache();
      addTearDown(cache.dispose);

      cache.ensureSize(const Size(800, 600));
      final v1 = cache.layerVersion;
      cache.ensureSize(const Size(800, 600)); // 相同尺寸
      expect(cache.layerVersion, v1); // 版本不变
    });
  });

  // ============================================================
  // 笔画操作
  // ============================================================
  group('StrokeRasterCache — 笔画操作', () {
    late StrokeRasterCache cache;

    setUp(() {
      cache = StrokeRasterCache();
      cache.ensureSize(const Size(800, 600));
    });

    tearDown(() {
      cache.dispose();
    });

    test('addStroke 缓存笔画并递增版本', () async {
      final stroke = makeStroke('s1');
      await cache.addStroke(stroke);

      expect(cache.length, 1);
      expect(cache.cachedStrokeIds, contains('s1'));
      expect(cache.layerVersion, greaterThan(0));
      expect(cache.compositeImage, isNotNull);
    });

    test('addStroke 在画布尺寸为零时跳过', () async {
      final emptyCache = StrokeRasterCache();
      addTearDown(emptyCache.dispose);

      // 未调用 ensureSize，canvasSize == Size.zero
      await emptyCache.addStroke(makeStroke('s1'));
      expect(emptyCache.length, 0);
    });

    test('多条笔画增量合成', () async {
      await cache.addStroke(makeStroke('s1'));
      final v1 = cache.layerVersion;

      await cache.addStroke(makeStroke('s2'));
      final v2 = cache.layerVersion;

      await cache.addStroke(makeStroke('s3'));

      expect(cache.length, 3);
      expect(v2, greaterThan(v1));
      expect(cache.layerVersion, greaterThan(v2));
    });

    test('不同画笔类型均可光栅化', () async {
      for (final bt in BrushType.values) {
        final id = 'stroke-${bt.value}';
        await cache.addStroke(makeStroke(
          id,
          brushType: bt,
          color: bt == BrushType.eraser ? '#FFFFFF' : '#E07A5F',
        ));
        expect(cache.cachedStrokeIds, contains(id), reason: '$bt 应能光栅化');
      }
      expect(cache.length, BrushType.values.length);
    });

    test('clear 清除所有缓存', () async {
      await cache.addStroke(makeStroke('s1'));
      await cache.addStroke(makeStroke('s2'));
      expect(cache.length, 2);

      await cache.clear();
      expect(cache.length, 0);
      expect(cache.compositeImage, isNull);
      expect(cache.cachedStrokeIds, isEmpty);
    });

    test('syncStrokes 添加缺失笔画', () async {
      await cache.addStroke(makeStroke('s1'));
      expect(cache.length, 1);

      // syncStrokes 传入 s1 + s2，应只添加 s2
      await cache.syncStrokes([makeStroke('s1'), makeStroke('s2')]);
      expect(cache.length, 2);
      expect(cache.cachedStrokeIds, containsAll(['s1', 's2']));
    });

    test('syncStrokes 移除多余笔画（模拟撤销）', () async {
      await cache.addStroke(makeStroke('s1'));
      await cache.addStroke(makeStroke('s2'));
      expect(cache.length, 2);

      // syncStrokes 只保留 s1，移除 s2
      await cache.syncStrokes([makeStroke('s1')]);
      expect(cache.length, 1);
      expect(cache.cachedStrokeIds, {'s1'});
    });

    test('syncStrokes 无变化时不增加版本', () async {
      await cache.addStroke(makeStroke('s1'));
      final v = cache.layerVersion;

      // 传入完全相同的笔画列表
      await cache.syncStrokes([makeStroke('s1')]);
      expect(cache.layerVersion, v);
    });

    test('invalidateAll 重建所有缓存', () async {
      await cache.addStroke(makeStroke('s1'));
      final v1 = cache.layerVersion;

      // 尺寸变化触发 invalidateAll
      cache.ensureSize(const Size(1024, 768));
      await cache.addStroke(makeStroke('s1')); // 重建后重新添加

      // 版本应高于之前（因为 invalidateAll + addStroke 都递增）
      expect(cache.layerVersion, greaterThan(v1));
    });
  });

  // ============================================================
  // 空边界条件
  // ============================================================
  group('StrokeRasterCache — 边界条件', () {
    test('单点笔画不会生成缓存条目', () async {
      final cache = StrokeRasterCache();
      cache.ensureSize(const Size(800, 600));
      addTearDown(cache.dispose);

      final singlePointStroke = Stroke(
        id: 'single',
        points: [const StrokePoint(x: 50, y: 50)],
      );
      await cache.addStroke(singlePointStroke);

      // 单点 → pointsToOutline 返回空 → _rasterizeStroke 返回 null
      expect(cache.length, 0);
    });

    test('空笔画列表的 syncStrokes 不报错', () async {
      final cache = StrokeRasterCache();
      cache.ensureSize(const Size(800, 600));
      addTearDown(cache.dispose);

      await cache.syncStrokes([]); // 不应抛
      expect(cache.length, 0);
    });
  });
}