canvaskit_api.dart

// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

/// Bindings for CanvasKit JavaScript API.
///
/// Prefer keeping the original CanvasKit names so it is easier to locate
/// the API behind these bindings in the Skia source code.
// ignore_for_file: non_constant_identifier_names
@JS()
library canvaskit_api;

import 'dart:async';
import 'dart:convert';
import 'dart:js_util' as js_util;
import 'dart:typed_data';

import 'package:js/js.dart';
import 'package:meta/meta.dart';
import 'package:ui/ui.dart' as ui;

import '../browser_detection.dart';
import '../configuration.dart';
import '../dom.dart';
import '../profiler.dart';
import 'renderer.dart';

/// Entrypoint into the CanvasKit API.
late CanvasKit canvasKit;

late CanvasKitVariant _canvasKitVariant;

/// Which variant of CanvasKit we are using.
CanvasKitVariant get canvasKitVariant => _canvasKitVariant;
set canvasKitVariant(CanvasKitVariant value) {
  if (value == CanvasKitVariant.auto) {
    throw ArgumentError.value(
      value,
      'value',
      'CanvasKitVariant.auto is not a valid value for canvasKitVariant',
    );
  }
  _canvasKitVariant = value;
}


/// Sets the [CanvasKit] object on `window` so we can use `@JS()` to bind to
/// static APIs.
///
/// See, e.g. [SkPaint].
///
/// This also acts as a cache of an initialized CanvasKit instance. We can use
/// this, for example, to perform a hot restart without needing to redownload
/// and reinitialize CanvasKit.
@JS('window.flutterCanvasKit')
external set windowFlutterCanvasKit(CanvasKit? value);

@JS('window.flutterCanvasKit')
external CanvasKit? get windowFlutterCanvasKit;

@JS()
@anonymous
@staticInterop
class CanvasKit {}

extension CanvasKitExtension on CanvasKit {
  external SkBlendModeEnum get BlendMode;
  external SkPaintStyleEnum get PaintStyle;
  external SkStrokeCapEnum get StrokeCap;
  external SkStrokeJoinEnum get StrokeJoin;
  external SkBlurStyleEnum get BlurStyle;
  external SkTileModeEnum get TileMode;
  external SkFilterModeEnum get FilterMode;
  external SkMipmapModeEnum get MipmapMode;
  external SkFillTypeEnum get FillType;
  external SkAlphaTypeEnum get AlphaType;
  external SkColorTypeEnum get ColorType;
  external SkPathOpEnum get PathOp;
  external SkClipOpEnum get ClipOp;
  external SkPointModeEnum get PointMode;
  external SkVertexModeEnum get VertexMode;
  external SkRectHeightStyleEnum get RectHeightStyle;
  external SkRectWidthStyleEnum get RectWidthStyle;
  external SkAffinityEnum get Affinity;
  external SkTextAlignEnum get TextAlign;
  external SkTextHeightBehaviorEnum get TextHeightBehavior;
  external SkTextDirectionEnum get TextDirection;
  external SkFontWeightEnum get FontWeight;
  external SkFontSlantEnum get FontSlant;
  external SkAnimatedImage? MakeAnimatedImageFromEncoded(Uint8List imageData);
  external SkShaderNamespace get Shader;
  external SkMaskFilterNamespace get MaskFilter;
  external SkColorFilterNamespace get ColorFilter;
  external SkImageFilterNamespace get ImageFilter;
  external SkPathNamespace get Path;
  external SkTonalColors computeTonalColors(SkTonalColors inTonalColors);
  external SkVertices MakeVertices(
    SkVertexMode mode,
    Float32List positions,
    Float32List? textureCoordinates,
    Uint32List? colors,
    Uint16List? indices,
  );
  external SkParagraphBuilderNamespace get ParagraphBuilder;
  external SkParagraphStyle ParagraphStyle(
      SkParagraphStyleProperties properties);
  external SkTextStyle TextStyle(SkTextStyleProperties properties);
  external SkSurface MakeWebGLCanvasSurface(DomCanvasElement canvas);
  external SkSurface MakeSurface(
    double width,
    double height,
  );
  external Uint8List getDataBytes(
    SkData skData,
  );

  // Text decoration enum is embedded in the CanvasKit object itself.
  external double get NoDecoration;
  external double get UnderlineDecoration;
  external double get OverlineDecoration;
  external double get LineThroughDecoration;
  // End of text decoration enum.

  external SkTextDecorationStyleEnum get DecorationStyle;
  external SkTextBaselineEnum get TextBaseline;
  external SkPlaceholderAlignmentEnum get PlaceholderAlignment;

  external SkFontMgrNamespace get FontMgr;
  external TypefaceFontProviderNamespace get TypefaceFontProvider;
  external SkTypefaceFactory get Typeface;
  external double GetWebGLContext(
      DomCanvasElement canvas, SkWebGLContextOptions options);
  external SkGrContext MakeGrContext(double glContext);
  external SkSurface? MakeOnScreenGLSurface(
    SkGrContext grContext,
    double width,
    double height,
    ColorSpace colorSpace,
    int sampleCount,
    int stencil,
  );
  external SkSurface? MakeRenderTarget(
    SkGrContext grContext,
    int width,
    int height,
  );
  external SkSurface MakeSWCanvasSurface(DomCanvasElement canvas);

  /// Creates an image from decoded pixels represented as a list of bytes.
  ///
  /// The pixel data must be encoded according to the image info in [info].
  ///
  /// Typically pixel data is obtained using [SkImage.readPixels]. The
  /// parameters specified in [SkImageInfo] passed [SkImage.readPixels] must
  /// match [info].
  external SkImage? MakeImage(
    SkImageInfo info,
    Uint8List pixels,
    double bytesPerRow,
  );
  external SkImage? MakeLazyImageFromTextureSource(
    Object src,
    SkPartialImageInfo info,
  );
}

@JS('window.CanvasKitInit')
external Object _CanvasKitInit(CanvasKitInitOptions options);

Future<CanvasKit> CanvasKitInit(CanvasKitInitOptions options) {
  return js_util.promiseToFuture<CanvasKit>(_CanvasKitInit(options));
}

typedef LocateFileCallback = String Function(String file, String unusedBase);

@JS()
@anonymous
@staticInterop
class CanvasKitInitOptions {
  external factory CanvasKitInitOptions({
    required LocateFileCallback locateFile,
  });
}

@JS('window.flutterCanvasKit.ColorSpace.SRGB')
external ColorSpace get SkColorSpaceSRGB;

@JS()
@staticInterop
class ColorSpace {}

@JS()
@anonymous
@staticInterop
class SkWebGLContextOptions {
  external factory SkWebGLContextOptions({
    required double antialias,
    // WebGL version: 1 or 2.
    required double majorVersion,
  });
}

@JS('window.flutterCanvasKit.Surface')
@staticInterop
class SkSurface {}

extension SkSurfaceExtension on SkSurface {
  external SkCanvas getCanvas();
  external void flush();
  external double width();
  external double height();
  external void dispose();
  external SkImage makeImageSnapshot();
}

@JS()
@staticInterop
class SkGrContext {}

extension SkGrContextExtension on SkGrContext {
  external void setResourceCacheLimitBytes(double limit);
  external void releaseResourcesAndAbandonContext();
  external void delete();
}

@JS()
@anonymous
@staticInterop
class SkFontSlantEnum {}

extension SkFontSlantEnumExtension on SkFontSlantEnum {
  external SkFontSlant get Upright;
  external SkFontSlant get Italic;
}

@JS('window.flutterCanvasKit.FontSlant')
@staticInterop
class SkFontSlant {}

extension SkFontSlantExtension on SkFontSlant {
  external double get value;
}

final List<SkFontSlant> _skFontSlants = <SkFontSlant>[
  canvasKit.FontSlant.Upright,
  canvasKit.FontSlant.Italic,
];

SkFontSlant toSkFontSlant(ui.FontStyle style) {
  return _skFontSlants[style.index];
}

@JS()
@anonymous
@staticInterop
class SkFontWeightEnum {}

extension SkFontWeightEnumExtension on SkFontWeightEnum {
  external SkFontWeight get Thin;
  external SkFontWeight get ExtraLight;
  external SkFontWeight get Light;
  external SkFontWeight get Normal;
  external SkFontWeight get Medium;
  external SkFontWeight get SemiBold;
  external SkFontWeight get Bold;
  external SkFontWeight get ExtraBold;
  external SkFontWeight get ExtraBlack;
}

@JS()
@staticInterop
class SkFontWeight {}

extension SkFontWeightExtension on SkFontWeight {
  external double get value;
}

final List<SkFontWeight> _skFontWeights = <SkFontWeight>[
  canvasKit.FontWeight.Thin,
  canvasKit.FontWeight.ExtraLight,
  canvasKit.FontWeight.Light,
  canvasKit.FontWeight.Normal,
  canvasKit.FontWeight.Medium,
  canvasKit.FontWeight.SemiBold,
  canvasKit.FontWeight.Bold,
  canvasKit.FontWeight.ExtraBold,
  canvasKit.FontWeight.ExtraBlack,
];

SkFontWeight toSkFontWeight(ui.FontWeight weight) {
  return _skFontWeights[weight.index];
}

@JS()
@staticInterop
class SkAffinityEnum {}

extension SkAffinityEnumExtension on SkAffinityEnum {
  external SkAffinity get Upstream;
  external SkAffinity get Downstream;
}

@JS()
@staticInterop
class SkAffinity {}

extension SkAffinityExtension on SkAffinity {
  external double get value;
}

final List<SkAffinity> _skAffinitys = <SkAffinity>[
  canvasKit.Affinity.Upstream,
  canvasKit.Affinity.Downstream,
];

SkAffinity toSkAffinity(ui.TextAffinity affinity) {
  return _skAffinitys[affinity.index];
}

@JS()
@staticInterop
class SkTextDirectionEnum {}

extension SkTextDirectionEnumExtension on SkTextDirectionEnum {
  external SkTextDirection get RTL;
  external SkTextDirection get LTR;
}

@JS()
@staticInterop
class SkTextDirection {}

extension SkTextDirectionExtension on SkTextDirection {
  external double get value;
}

// Flutter enumerates text directions as RTL, LTR, while CanvasKit
// enumerates them LTR, RTL.
final List<SkTextDirection> _skTextDirections = <SkTextDirection>[
  canvasKit.TextDirection.RTL,
  canvasKit.TextDirection.LTR,
];

SkTextDirection toSkTextDirection(ui.TextDirection direction) {
  return _skTextDirections[direction.index];
}

@JS()
@staticInterop
class SkTextAlignEnum {}

extension SkTextAlignEnumExtension on SkTextAlignEnum {
  external SkTextAlign get Left;
  external SkTextAlign get Right;
  external SkTextAlign get Center;
  external SkTextAlign get Justify;
  external SkTextAlign get Start;
  external SkTextAlign get End;
}

@JS()
@staticInterop
class SkTextAlign {}

extension SkTextAlignExtension on SkTextAlign {
  external double get value;
}

final List<SkTextAlign> _skTextAligns = <SkTextAlign>[
  canvasKit.TextAlign.Left,
  canvasKit.TextAlign.Right,
  canvasKit.TextAlign.Center,
  canvasKit.TextAlign.Justify,
  canvasKit.TextAlign.Start,
  canvasKit.TextAlign.End,
];

SkTextAlign toSkTextAlign(ui.TextAlign align) {
  return _skTextAligns[align.index];
}

@JS()
@staticInterop
class SkTextHeightBehaviorEnum {}

extension SkTextHeightBehaviorEnumExtension on SkTextHeightBehaviorEnum {
  external SkTextHeightBehavior get All;
  external SkTextHeightBehavior get DisableFirstAscent;
  external SkTextHeightBehavior get DisableLastDescent;
  external SkTextHeightBehavior get DisableAll;
}

@JS()
@staticInterop
class SkTextHeightBehavior {}

extension SkTextHeightBehaviorExtension on SkTextHeightBehavior {
  external double get value;
}

final List<SkTextHeightBehavior> _skTextHeightBehaviors =
    <SkTextHeightBehavior>[
  canvasKit.TextHeightBehavior.All,
  canvasKit.TextHeightBehavior.DisableFirstAscent,
  canvasKit.TextHeightBehavior.DisableLastDescent,
  canvasKit.TextHeightBehavior.DisableAll,
];

SkTextHeightBehavior toSkTextHeightBehavior(ui.TextHeightBehavior behavior) {
  final int index = (behavior.applyHeightToFirstAscent ? 0 : 1 << 0) |
      (behavior.applyHeightToLastDescent ? 0 : 1 << 1);
  return _skTextHeightBehaviors[index];
}

@JS()
@staticInterop
class SkRectHeightStyleEnum {}

extension SkRectHeightStyleEnumExtension on SkRectHeightStyleEnum {
  external SkRectHeightStyle get Tight;
  external SkRectHeightStyle get Max;
  external SkRectHeightStyle get IncludeLineSpacingMiddle;
  external SkRectHeightStyle get IncludeLineSpacingTop;
  external SkRectHeightStyle get IncludeLineSpacingBottom;
  external SkRectHeightStyle get Strut;
}

@JS()
@staticInterop
class SkRectHeightStyle {}

extension SkRectHeightStyleExtension on SkRectHeightStyle {
  external double get value;
}

final List<SkRectHeightStyle> _skRectHeightStyles = <SkRectHeightStyle>[
  canvasKit.RectHeightStyle.Tight,
  canvasKit.RectHeightStyle.Max,
  canvasKit.RectHeightStyle.IncludeLineSpacingMiddle,
  canvasKit.RectHeightStyle.IncludeLineSpacingTop,
  canvasKit.RectHeightStyle.IncludeLineSpacingBottom,
  canvasKit.RectHeightStyle.Strut,
];

SkRectHeightStyle toSkRectHeightStyle(ui.BoxHeightStyle style) {
  return _skRectHeightStyles[style.index];
}

@JS()
@staticInterop
class SkRectWidthStyleEnum {}

extension SkRectWidthStyleEnumExtension on SkRectWidthStyleEnum {
  external SkRectWidthStyle get Tight;
  external SkRectWidthStyle get Max;
}

@JS()
@staticInterop
class SkRectWidthStyle {}

extension SkRectWidthStyleExtension on SkRectWidthStyle {
  external double get value;
}

final List<SkRectWidthStyle> _skRectWidthStyles = <SkRectWidthStyle>[
  canvasKit.RectWidthStyle.Tight,
  canvasKit.RectWidthStyle.Max,
];

SkRectWidthStyle toSkRectWidthStyle(ui.BoxWidthStyle style) {
  final int index = style.index;
  return _skRectWidthStyles[index < 2 ? index : 0];
}

@JS()
@staticInterop
class SkVertexModeEnum {}

extension SkVertexModeEnumExtension on SkVertexModeEnum {
  external SkVertexMode get Triangles;
  external SkVertexMode get TrianglesStrip;
  external SkVertexMode get TriangleFan;
}

@JS()
@staticInterop
class SkVertexMode {}

extension SkVertexModeExtension on SkVertexMode {
  external double get value;
}

final List<SkVertexMode> _skVertexModes = <SkVertexMode>[
  canvasKit.VertexMode.Triangles,
  canvasKit.VertexMode.TrianglesStrip,
  canvasKit.VertexMode.TriangleFan,
];

SkVertexMode toSkVertexMode(ui.VertexMode mode) {
  return _skVertexModes[mode.index];
}

@JS()
@staticInterop
class SkPointModeEnum {}

extension SkPointModeEnumExtension on SkPointModeEnum {
  external SkPointMode get Points;
  external SkPointMode get Lines;
  external SkPointMode get Polygon;
}

@JS()
@staticInterop
class SkPointMode {}

extension SkPointModeExtension on SkPointMode {
  external double get value;
}

final List<SkPointMode> _skPointModes = <SkPointMode>[
  canvasKit.PointMode.Points,
  canvasKit.PointMode.Lines,
  canvasKit.PointMode.Polygon,
];

SkPointMode toSkPointMode(ui.PointMode mode) {
  return _skPointModes[mode.index];
}

@JS()
@staticInterop
class SkClipOpEnum {}

extension SkClipOpEnumExtension on SkClipOpEnum {
  external SkClipOp get Difference;
  external SkClipOp get Intersect;
}

@JS()
@staticInterop
class SkClipOp {}

extension SkClipOpExtension on SkClipOp {
  external double get value;
}

final List<SkClipOp> _skClipOps = <SkClipOp>[
  canvasKit.ClipOp.Difference,
  canvasKit.ClipOp.Intersect,
];

SkClipOp toSkClipOp(ui.ClipOp clipOp) {
  return _skClipOps[clipOp.index];
}

@JS()
@staticInterop
class SkFillTypeEnum {}

extension SkFillTypeEnumExtension on SkFillTypeEnum {
  external SkFillType get Winding;
  external SkFillType get EvenOdd;
}

@JS()
@staticInterop
class SkFillType {}

extension SkFillTypeExtension on SkFillType {
  external double get value;
}

final List<SkFillType> _skFillTypes = <SkFillType>[
  canvasKit.FillType.Winding,
  canvasKit.FillType.EvenOdd,
];

SkFillType toSkFillType(ui.PathFillType fillType) {
  return _skFillTypes[fillType.index];
}

@JS()
@staticInterop
class SkPathOpEnum {}

extension SkPathOpEnumExtension on SkPathOpEnum {
  external SkPathOp get Difference;
  external SkPathOp get Intersect;
  external SkPathOp get Union;
  external SkPathOp get XOR;
  external SkPathOp get ReverseDifference;
}

@JS()
@staticInterop
class SkPathOp {}

extension SkPathOpExtension on SkPathOp {
  external double get value;
}

final List<SkPathOp> _skPathOps = <SkPathOp>[
  canvasKit.PathOp.Difference,
  canvasKit.PathOp.Intersect,
  canvasKit.PathOp.Union,
  canvasKit.PathOp.XOR,
  canvasKit.PathOp.ReverseDifference,
];

SkPathOp toSkPathOp(ui.PathOperation pathOp) {
  return _skPathOps[pathOp.index];
}

@JS()
@staticInterop
class SkBlurStyleEnum {}

extension SkBlurStyleEnumExtension on SkBlurStyleEnum {
  external SkBlurStyle get Normal;
  external SkBlurStyle get Solid;
  external SkBlurStyle get Outer;
  external SkBlurStyle get Inner;
}

@JS()
@staticInterop
class SkBlurStyle {}

extension SkBlurStyleExtension on SkBlurStyle {
  external double get value;
}

final List<SkBlurStyle> _skBlurStyles = <SkBlurStyle>[
  canvasKit.BlurStyle.Normal,
  canvasKit.BlurStyle.Solid,
  canvasKit.BlurStyle.Outer,
  canvasKit.BlurStyle.Inner,
];

SkBlurStyle toSkBlurStyle(ui.BlurStyle style) {
  return _skBlurStyles[style.index];
}

@JS()
@staticInterop
class SkStrokeCapEnum {}

extension SkStrokeCapEnumExtension on SkStrokeCapEnum {
  external SkStrokeCap get Butt;
  external SkStrokeCap get Round;
  external SkStrokeCap get Square;
}

@JS()
@staticInterop
class SkStrokeCap {}

extension SkStrokeCapExtension on SkStrokeCap {
  external double get value;
}

final List<SkStrokeCap> _skStrokeCaps = <SkStrokeCap>[
  canvasKit.StrokeCap.Butt,
  canvasKit.StrokeCap.Round,
  canvasKit.StrokeCap.Square,
];

SkStrokeCap toSkStrokeCap(ui.StrokeCap strokeCap) {
  return _skStrokeCaps[strokeCap.index];
}

@JS()
@staticInterop
class SkPaintStyleEnum {}

extension SkPaintStyleEnumExtension on SkPaintStyleEnum {
  external SkPaintStyle get Stroke;
  external SkPaintStyle get Fill;
}

@JS()
@staticInterop
class SkPaintStyle {}

extension SkPaintStyleExtension on SkPaintStyle {
  external double get value;
}

final List<SkPaintStyle> _skPaintStyles = <SkPaintStyle>[
  canvasKit.PaintStyle.Fill,
  canvasKit.PaintStyle.Stroke,
];

SkPaintStyle toSkPaintStyle(ui.PaintingStyle paintStyle) {
  return _skPaintStyles[paintStyle.index];
}

@JS()
@staticInterop
class SkBlendModeEnum {}

extension SkBlendModeEnumExtension on SkBlendModeEnum {
  external SkBlendMode get Clear;
  external SkBlendMode get Src;
  external SkBlendMode get Dst;
  external SkBlendMode get SrcOver;
  external SkBlendMode get DstOver;
  external SkBlendMode get SrcIn;
  external SkBlendMode get DstIn;
  external SkBlendMode get SrcOut;
  external SkBlendMode get DstOut;
  external SkBlendMode get SrcATop;
  external SkBlendMode get DstATop;
  external SkBlendMode get Xor;
  external SkBlendMode get Plus;
  external SkBlendMode get Modulate;
  external SkBlendMode get Screen;
  external SkBlendMode get Overlay;
  external SkBlendMode get Darken;
  external SkBlendMode get Lighten;
  external SkBlendMode get ColorDodge;
  external SkBlendMode get ColorBurn;
  external SkBlendMode get HardLight;
  external SkBlendMode get SoftLight;
  external SkBlendMode get Difference;
  external SkBlendMode get Exclusion;
  external SkBlendMode get Multiply;
  external SkBlendMode get Hue;
  external SkBlendMode get Saturation;
  external SkBlendMode get Color;
  external SkBlendMode get Luminosity;
}

@JS()
@staticInterop
class SkBlendMode {}

extension SkBlendModeExtension on SkBlendMode {
  external double get value;
}

final List<SkBlendMode> _skBlendModes = <SkBlendMode>[
  canvasKit.BlendMode.Clear,
  canvasKit.BlendMode.Src,
  canvasKit.BlendMode.Dst,
  canvasKit.BlendMode.SrcOver,
  canvasKit.BlendMode.DstOver,
  canvasKit.BlendMode.SrcIn,
  canvasKit.BlendMode.DstIn,
  canvasKit.BlendMode.SrcOut,
  canvasKit.BlendMode.DstOut,
  canvasKit.BlendMode.SrcATop,
  canvasKit.BlendMode.DstATop,
  canvasKit.BlendMode.Xor,
  canvasKit.BlendMode.Plus,
  canvasKit.BlendMode.Modulate,
  canvasKit.BlendMode.Screen,
  canvasKit.BlendMode.Overlay,
  canvasKit.BlendMode.Darken,
  canvasKit.BlendMode.Lighten,
  canvasKit.BlendMode.ColorDodge,
  canvasKit.BlendMode.ColorBurn,
  canvasKit.BlendMode.HardLight,
  canvasKit.BlendMode.SoftLight,
  canvasKit.BlendMode.Difference,
  canvasKit.BlendMode.Exclusion,
  canvasKit.BlendMode.Multiply,
  canvasKit.BlendMode.Hue,
  canvasKit.BlendMode.Saturation,
  canvasKit.BlendMode.Color,
  canvasKit.BlendMode.Luminosity,
];

SkBlendMode toSkBlendMode(ui.BlendMode blendMode) {
  return _skBlendModes[blendMode.index];
}

@JS()
@staticInterop
class SkStrokeJoinEnum {}

extension SkStrokeJoinEnumExtension on SkStrokeJoinEnum {
  external SkStrokeJoin get Miter;
  external SkStrokeJoin get Round;
  external SkStrokeJoin get Bevel;
}

@JS()
@staticInterop
class SkStrokeJoin {}

extension SkStrokeJoinExtension on SkStrokeJoin {
  external double get value;
}

final List<SkStrokeJoin> _skStrokeJoins = <SkStrokeJoin>[
  canvasKit.StrokeJoin.Miter,
  canvasKit.StrokeJoin.Round,
  canvasKit.StrokeJoin.Bevel,
];

SkStrokeJoin toSkStrokeJoin(ui.StrokeJoin strokeJoin) {
  return _skStrokeJoins[strokeJoin.index];
}

@JS()
@staticInterop
class SkTileModeEnum {}

extension SkTileModeEnumExtension on SkTileModeEnum {
  external SkTileMode get Clamp;
  external SkTileMode get Repeat;
  external SkTileMode get Mirror;
  external SkTileMode get Decal;
}

@JS()
@staticInterop
class SkTileMode {}

extension SkTileModeExtension on SkTileMode {
  external double get value;
}

final List<SkTileMode> _skTileModes = <SkTileMode>[
  canvasKit.TileMode.Clamp,
  canvasKit.TileMode.Repeat,
  canvasKit.TileMode.Mirror,
  canvasKit.TileMode.Decal,
];

SkTileMode toSkTileMode(ui.TileMode mode) {
  return _skTileModes[mode.index];
}

@JS()
@staticInterop
class SkFilterModeEnum {}

extension SkFilterModeEnumExtension on SkFilterModeEnum {
  external SkFilterMode get Nearest;
  external SkFilterMode get Linear;
}

@JS()
@staticInterop
class SkFilterMode {}

extension SkFilterModeExtension on SkFilterMode {
  external double get value;
}

SkFilterMode toSkFilterMode(ui.FilterQuality filterQuality) {
  return filterQuality == ui.FilterQuality.none
      ? canvasKit.FilterMode.Nearest
      : canvasKit.FilterMode.Linear;
}

@JS()
@staticInterop
class SkMipmapModeEnum {}

extension SkMipmapModeEnumExtension on SkMipmapModeEnum {
  external SkMipmapMode get None;
  external SkMipmapMode get Nearest;
  external SkMipmapMode get Linear;
}

@JS()
@staticInterop
class SkMipmapMode {}

extension SkMipmapModeExtension on SkMipmapMode {
  external double get value;
}

SkMipmapMode toSkMipmapMode(ui.FilterQuality filterQuality) {
  return filterQuality == ui.FilterQuality.medium
      ? canvasKit.MipmapMode.Linear
      : canvasKit.MipmapMode.None;
}

@JS()
@staticInterop
class SkAlphaTypeEnum {}

extension SkAlphaTypeEnumExtension on SkAlphaTypeEnum {
  external SkAlphaType get Opaque;
  external SkAlphaType get Premul;
  external SkAlphaType get Unpremul;
}

@JS()
@staticInterop
class SkAlphaType {}

extension SkAlphaTypeExtension on SkAlphaType {
  external double get value;
}

@JS()
@staticInterop
class SkColorTypeEnum {}

extension SkColorTypeEnumExtension on SkColorTypeEnum {
  external SkColorType get Alpha_8;
  external SkColorType get RGB_565;
  external SkColorType get ARGB_4444;
  external SkColorType get RGBA_8888;
  external SkColorType get RGB_888x;
  external SkColorType get BGRA_8888;
  external SkColorType get RGBA_1010102;
  external SkColorType get RGB_101010x;
  external SkColorType get Gray_8;
  external SkColorType get RGBA_F16;
  external SkColorType get RGBA_F32;
}

@JS()
@staticInterop
class SkColorType {}

extension SkColorTypeExtension on SkColorType {
  external double get value;
}

@JS()
@anonymous
@staticInterop
class SkAnimatedImage {}

extension SkAnimatedImageExtension on SkAnimatedImage {
  external double getFrameCount();

  external double getRepetitionCount();

  /// Returns duration in milliseconds.
  external double currentFrameDuration();

  /// Advances to the next frame and returns its duration in milliseconds.
  external double decodeNextFrame();

  external SkImage makeImageAtCurrentFrame();
  external double width();
  external double height();

  /// Deletes the C++ object.
  ///
  /// This object is no longer usable after calling this method.
  external void delete();
  external bool isDeleted();
}

@JS()
@anonymous
@staticInterop
class SkImage {}

extension SkImageExtension on SkImage {
  external void delete();
  external double width();
  external double height();
  external SkShader makeShaderCubic(
    SkTileMode tileModeX,
    SkTileMode tileModeY,
    double B,
    double C,
    Float32List? matrix, // 3x3 matrix
  );
  external SkShader makeShaderOptions(
    SkTileMode tileModeX,
    SkTileMode tileModeY,
    SkFilterMode filterMode,
    SkMipmapMode mipmapMode,
    Float32List? matrix, // 3x3 matrix
  );
  external Uint8List readPixels(double srcX, double srcY, SkImageInfo imageInfo);
  external Uint8List? encodeToBytes();
  external bool isAliasOf(SkImage other);
  external bool isDeleted();
}

@JS()
@staticInterop
class SkShaderNamespace {}

extension SkShaderNamespaceExtension on SkShaderNamespace {
  external SkShader MakeLinearGradient(
    Float32List from, // 2-element array
    Float32List to, // 2-element array
    Uint32List colors,
    Float32List colorStops,
    SkTileMode tileMode,
    Float32List? matrix,
  );

  external SkShader MakeRadialGradient(
    Float32List center, // 2-element array
    double radius,
    Uint32List colors,
    Float32List colorStops,
    SkTileMode tileMode,
    Float32List? matrix, // 3x3 matrix
    double flags,
  );

  external SkShader MakeTwoPointConicalGradient(
    Float32List focal,
    double focalRadius,
    Float32List center,
    double radius,
    Uint32List colors,
    Float32List colorStops,
    SkTileMode tileMode,
    Float32List? matrix, // 3x3 matrix
    double flags,
  );

  external SkShader MakeSweepGradient(
    double cx,
    double cy,
    Uint32List colors,
    Float32List colorStops,
    SkTileMode tileMode,
    Float32List? matrix, // 3x3 matrix
    double flags,
    double startAngle,
    double endAngle,
  );
}

@JS()
@anonymous
@staticInterop
class SkShader {}

extension SkShaderExtension on SkShader {
  external void delete();
}

@JS()
@staticInterop
class SkMaskFilterNamespace {}

extension SkMaskFilterNamespaceExtension on SkMaskFilterNamespace {
  // Creates a blur MaskFilter.
  //
  // Returns `null` if [sigma] is 0 or infinite.
  external SkMaskFilter? MakeBlur(
      SkBlurStyle blurStyle, double sigma, bool respectCTM);
}

// This needs to be bound to top-level because SkPaint is initialized
// with `new`. Also in Dart you can't write this:
//
//     external SkPaint SkPaint();
@JS('window.flutterCanvasKit.Paint')
@staticInterop
class SkPaint {
  external factory SkPaint();
}

extension SkPaintExtension on SkPaint {
  external void setBlendMode(SkBlendMode blendMode);
  external void setStyle(SkPaintStyle paintStyle);
  external void setStrokeWidth(double width);
  external void setStrokeCap(SkStrokeCap cap);
  external void setStrokeJoin(SkStrokeJoin join);
  external void setAntiAlias(bool isAntiAlias);
  external void setColorInt(double color);
  external void setShader(SkShader? shader);
  external void setMaskFilter(SkMaskFilter? maskFilter);
  external void setColorFilter(SkColorFilter? colorFilter);
  external void setStrokeMiter(double miterLimit);
  external void setImageFilter(SkImageFilter? imageFilter);
  external void delete();
}

@JS()
@anonymous
@staticInterop
abstract class CkFilterOptions {}

@JS()
@anonymous
@staticInterop
class _CkCubicFilterOptions extends CkFilterOptions {
  external factory _CkCubicFilterOptions({double B, double C});
}

@JS()
@anonymous
@staticInterop
class _CkTransformFilterOptions extends CkFilterOptions {
  external factory _CkTransformFilterOptions(
      {SkFilterMode filter, SkMipmapMode mipmap});
}

final Map<ui.FilterQuality, CkFilterOptions> _filterOptions =
    <ui.FilterQuality, CkFilterOptions>{
  ui.FilterQuality.none: _CkTransformFilterOptions(
    filter: canvasKit.FilterMode.Nearest,
    mipmap: canvasKit.MipmapMode.None,
  ),
  ui.FilterQuality.low: _CkTransformFilterOptions(
    filter: canvasKit.FilterMode.Linear,
    mipmap: canvasKit.MipmapMode.None,
  ),
  ui.FilterQuality.medium: _CkTransformFilterOptions(
    filter: canvasKit.FilterMode.Linear,
    mipmap: canvasKit.MipmapMode.Linear,
  ),
  ui.FilterQuality.high: _CkCubicFilterOptions(
    B: 1.0 / 3,
    C: 1.0 / 3,
  ),
};

CkFilterOptions toSkFilterOptions(ui.FilterQuality filterQuality) {
  return _filterOptions[filterQuality]!;
}

@JS()
@anonymous
@staticInterop
class SkMaskFilter {}

extension SkMaskFilterExtension on SkMaskFilter {
  external void delete();
}

@JS()
@staticInterop
class SkColorFilterNamespace {}

extension SkColorFilterNamespaceExtension on SkColorFilterNamespace {
  external SkColorFilter? MakeBlend(Float32List color, SkBlendMode blendMode);
  external SkColorFilter MakeMatrix(
    Float32List matrix, // 20-element matrix
  );
  external SkColorFilter MakeLinearToSRGBGamma();
  external SkColorFilter MakeSRGBToLinearGamma();
  external SkColorFilter MakeCompose(SkColorFilter? outer, SkColorFilter inner);
}

@JS()
@anonymous
@staticInterop
class SkColorFilter {}

extension SkColorFilterExtension on SkColorFilter {
  external void delete();
}

@JS()
@staticInterop
class SkImageFilterNamespace {}

extension SkImageFilterNamespaceExtension on SkImageFilterNamespace {
  external SkImageFilter MakeBlur(
    double sigmaX,
    double sigmaY,
    SkTileMode tileMode,
    void input, // we don't use this yet
  );

  external SkImageFilter MakeMatrixTransform(
    Float32List matrix, // 3x3 matrix
    CkFilterOptions filterOptions,
    void input, // we don't use this yet
  );

  external SkImageFilter MakeColorFilter(
    SkColorFilter colorFilter,
    void input, // we don't use this yet
  );

  external SkImageFilter MakeCompose(
    SkImageFilter outer,
    SkImageFilter inner,
  );
}

@JS()
@anonymous
@staticInterop
class SkImageFilter {}

extension SkImageFilterExtension on SkImageFilter {
  external void delete();
}

@JS()
@staticInterop
class SkPathNamespace {}

extension SkPathNamespaceExtension on SkPathNamespace {
  /// Creates an [SkPath] using commands obtained from [SkPath.toCmds].
  external SkPath MakeFromCmds(List<dynamic> pathCommands);

  /// Creates an [SkPath] by combining [path1] and [path2] using [pathOp].
  external SkPath MakeFromOp(SkPath path1, SkPath path2, SkPathOp pathOp);
}

/// Converts a 4x4 Flutter matrix (represented as a [Float32List] in
/// column major order) to an SkM44 which is a 4x4 matrix represented
/// as a [Float32List] in row major order.
Float32List toSkM44FromFloat32(Float32List matrix4) {
  final Float32List skM44 = Float32List(16);
  for (int r = 0; r < 4; r++) {
    for (int c = 0; c < 4; c++) {
      skM44[c * 4 + r] = matrix4[r * 4 + c];
    }
  }
  return skM44;
}

// Mappings from SkMatrix-index to input-index.
const List<int> _skMatrixIndexToMatrix4Index = <int>[
  0, 4, 12, // Row 1
  1, 5, 13, // Row 2
  3, 7, 15, // Row 3
];

/// Converts a 4x4 Flutter matrix (represented as a [Float32List]) to an
/// SkMatrix, which is a 3x3 transform matrix.
Float32List toSkMatrixFromFloat32(Float32List matrix4) {
  final Float32List skMatrix = Float32List(9);
  for (int i = 0; i < 9; ++i) {
    final int matrix4Index = _skMatrixIndexToMatrix4Index[i];
    if (matrix4Index < matrix4.length) {
      skMatrix[i] = matrix4[matrix4Index];
    } else {
      skMatrix[i] = 0.0;
    }
  }
  return skMatrix;
}

/// Converts a 4x4 Flutter matrix (represented as a [Float32List]) to an
/// SkMatrix, which is a 3x3 transform matrix.
Float32List toSkMatrixFromFloat64(Float64List matrix4) {
  final Float32List skMatrix = Float32List(9);
  for (int i = 0; i < 9; ++i) {
    final int matrix4Index = _skMatrixIndexToMatrix4Index[i];
    if (matrix4Index < matrix4.length) {
      skMatrix[i] = matrix4[matrix4Index];
    } else {
      skMatrix[i] = 0.0;
    }
  }
  return skMatrix;
}

/// Converts an [offset] into an `[x, y]` pair stored in a `Float32List`.
///
/// The returned list can be passed to CanvasKit API that take points.
Float32List toSkPoint(ui.Offset offset) {
  final Float32List point = Float32List(2);
  point[0] = offset.dx;
  point[1] = offset.dy;
  return point;
}

/// Color stops used when the framework specifies `null`.
final Float32List _kDefaultSkColorStops = Float32List(2)
  ..[0] = 0
  ..[1] = 1;

/// Converts a list of color stops into a Skia-compatible JS array or color stops.
///
/// In Flutter `null` means two color stops `[0, 1]` that in Skia must be specified explicitly.
Float32List toSkColorStops(List<double>? colorStops) {
  if (colorStops == null) {
    return _kDefaultSkColorStops;
  }

  final int len = colorStops.length;
  final Float32List skColorStops = Float32List(len);
  for (int i = 0; i < len; i++) {
    skColorStops[i] = colorStops[i];
  }
  return skColorStops;
}

@JS()
@staticInterop
abstract class _NativeType {}

@JS('Float32Array')
external _NativeType get _nativeFloat32ArrayType;

@JS('Uint32Array')
external _NativeType get _nativeUint32ArrayType;

@JS('window.flutterCanvasKit.Malloc')
external Object _malloc(_NativeType nativeType, double length);

/// Allocates a [Float32List] of [length] elements, backed by WASM memory,
/// managed by a [SkFloat32List].
///
/// To free the allocated array use [free].
SkFloat32List mallocFloat32List(int length) {
  return _malloc(_nativeFloat32ArrayType, length.toDouble()) as SkFloat32List;
}

/// Allocates a [Uint32List] of [length] elements, backed by WASM memory,
/// managed by a [SkUint32List].
///
/// To free the allocated array use [free].
SkUint32List mallocUint32List(int length) {
  return _malloc(_nativeUint32ArrayType, length.toDouble()) as SkUint32List;
}

/// Frees the WASM memory occupied by a [SkFloat32List] or [SkUint32List].
///
/// The [list] is no longer usable after calling this function.
///
/// Use this function to free lists owned by the engine.
@JS('window.flutterCanvasKit.Free')
external void free(MallocObj list);

@JS()
@staticInterop
abstract class MallocObj {}

/// Wraps a [Float32List] backed by WASM memory.
///
/// This wrapper is necessary because the raw [Float32List] will get detached
/// when WASM grows its memory. Call [toTypedArray] to get a new instance
/// that's attached to the current WASM memory block.
@JS()
@staticInterop
class SkFloat32List extends MallocObj {}

extension SkFloat32ListExtension on SkFloat32List {
  /// The number of objects this pointer refers to.
  external double length;

  /// Returns the [Float32List] object backed by WASM memory.
  ///
  /// Do not reuse the returned array across multiple WASM function/method
  /// invocations that may lead to WASM memory to grow. When WASM memory
  /// grows, the returned [Float32List] object becomes "detached" and is no
  /// longer usable. Instead, call this method every time you need to read from
  /// or write to the list.
  external Float32List toTypedArray();
}

/// Wraps a [Uint32List] backed by WASM memory.
///
/// This wrapper is necessary because the raw [Uint32List] will get detached
/// when WASM grows its memory. Call [toTypedArray] to get a new instance
/// that's attached to the current WASM memory block.
@JS()
@staticInterop
class SkUint32List extends MallocObj {}

extension SkUint32ListExtension on SkUint32List {
  /// The number of objects this pointer refers to.
  external double length;

  /// Returns the [Uint32List] object backed by WASM memory.
  ///
  /// Do not reuse the returned array across multiple WASM function/method
  /// invocations that may lead to WASM memory to grow. When WASM memory
  /// grows, the returned [Uint32List] object becomes "detached" and is no
  /// longer usable. Instead, call this method every time you need to read from
  /// or write to the list.
  external Uint32List toTypedArray();
}

/// Writes [color] information into the given [skColor] buffer.
Float32List _populateSkColor(SkFloat32List skColor, ui.Color color) {
  final Float32List array = skColor.toTypedArray();
  array[0] = color.red / 255.0;
  array[1] = color.green / 255.0;
  array[2] = color.blue / 255.0;
  array[3] = color.alpha / 255.0;
  return array;
}

/// Unpacks the [color] into CanvasKit-compatible representation stored
/// in a shared memory location #1.
///
/// Use this only for passing transient data to CanvasKit. Because the
/// memory is shared the value will not persist.
Float32List toSharedSkColor1(ui.Color color) {
  return _populateSkColor(_sharedSkColor1, color);
}

final SkFloat32List _sharedSkColor1 = mallocFloat32List(4);

/// Unpacks the [color] into CanvasKit-compatible representation stored
/// in a shared memory location #2.
///
/// Use this only for passing transient data to CanvasKit. Because the
/// memory is shared the value will not persist.
Float32List toSharedSkColor2(ui.Color color) {
  return _populateSkColor(_sharedSkColor2, color);
}

final SkFloat32List _sharedSkColor2 = mallocFloat32List(4);

/// Unpacks the [color] into CanvasKit-compatible representation stored
/// in a shared memory location #3.
///
/// Use this only for passing transient data to CanvasKit. Because the
/// memory is shared the value will not persist.
Float32List toSharedSkColor3(ui.Color color) {
  return _populateSkColor(_sharedSkColor3, color);
}

final SkFloat32List _sharedSkColor3 = mallocFloat32List(4);

@JS('window.flutterCanvasKit.Path')
@staticInterop
class SkPath {
  external factory SkPath();
  external factory SkPath.from(SkPath other);
}

extension SkPathExtension on SkPath {
  external void setFillType(SkFillType fillType);
  external void addArc(
    Float32List oval,
    double startAngleDegrees,
    double sweepAngleDegrees,
  );
  external void addOval(
    Float32List oval,
    bool counterClockWise,
    double startIndex,
  );
  external void addPath(
    SkPath other,
    double scaleX,
    double skewX,
    double transX,
    double skewY,
    double scaleY,
    double transY,
    double pers0,
    double pers1,
    double pers2,
    bool extendPath,
  );
  external void addPoly(
    Float32List points,
    bool close,
  );
  external void addRRect(
    Float32List rrect,
    bool counterClockWise,
  );
  external void addRect(
    Float32List rect,
  );
  external void arcToOval(
    Float32List oval,
    double startAngleDegrees,
    double sweepAngleDegrees,
    bool forceMoveTo,
  );
  external void arcToRotated(
    double radiusX,
    double radiusY,
    double rotation,
    bool useSmallArc,
    bool counterClockWise,
    double x,
    double y,
  );
  external void close();
  external void conicTo(
    double x1,
    double y1,
    double x2,
    double y2,
    double w,
  );
  external bool contains(
    double x,
    double y,
  );
  external void cubicTo(
    double x1,
    double y1,
    double x2,
    double y2,
    double x3,
    double y3,
  );
  external Float32List getBounds();
  external void lineTo(double x, double y);
  external void moveTo(double x, double y);
  external void quadTo(
    double x1,
    double y1,
    double x2,
    double y2,
  );
  external void rArcTo(
    double x,
    double y,
    double rotation,
    bool useSmallArc,
    bool counterClockWise,
    double deltaX,
    double deltaY,
  );
  external void rConicTo(
    double x1,
    double y1,
    double x2,
    double y2,
    double w,
  );
  external void rCubicTo(
    double x1,
    double y1,
    double x2,
    double y2,
    double x3,
    double y3,
  );
  external void rLineTo(double x, double y);
  external void rMoveTo(double x, double y);
  external void rQuadTo(
    double x1,
    double y1,
    double x2,
    double y2,
  );
  external void reset();
  external String toSVGString();
  external bool isEmpty();
  external SkPath copy();
  external void transform(
    double scaleX,
    double skewX,
    double transX,
    double skewY,
    double scaleY,
    double transY,
    double pers0,
    double pers1,
    double pers2,
  );

  /// Serializes the path into a list of commands.
  ///
  /// The list can be used to create a new [SkPath] using
  /// [CanvasKit.Path.MakeFromCmds].
  external List<dynamic> toCmds();

  external void delete();
}

@JS('window.flutterCanvasKit.ContourMeasureIter')
@staticInterop
class SkContourMeasureIter {
  external factory SkContourMeasureIter(
      SkPath path,
      bool forceClosed,
      double resScale);
}

extension SkContourMeasureIterExtension on SkContourMeasureIter {
  external SkContourMeasure? next();
  external void delete();
}

@JS()
@staticInterop
class SkContourMeasure {}

extension SkContourMeasureExtension on SkContourMeasure {
  external SkPath getSegment(double start, double end, bool startWithMoveTo);
  external Float32List getPosTan(double distance);
  external bool isClosed();
  external double length();
  external void delete();
}

// TODO(hterkelsen): Use a shared malloc'ed array for performance.
Float32List toSkRect(ui.Rect rect) {
  final Float32List skRect = Float32List(4);
  skRect[0] = rect.left;
  skRect[1] = rect.top;
  skRect[2] = rect.right;
  skRect[3] = rect.bottom;
  return skRect;
}

ui.Rect fromSkRect(Float32List skRect) {
  return ui.Rect.fromLTRB(skRect[0], skRect[1], skRect[2], skRect[3]);
}

ui.Rect rectFromSkIRect(Int32List skIRect) {
  return ui.Rect.fromLTRB(
    skIRect[0].toDouble(),
    skIRect[1].toDouble(),
    skIRect[2].toDouble(),
    skIRect[3].toDouble(),
  );
}

// TODO(hterkelsen): Use a shared malloc'ed array for performance.
Float32List toSkRRect(ui.RRect rrect) {
  final Float32List skRRect = Float32List(12);
  skRRect[0] = rrect.left;
  skRRect[1] = rrect.top;
  skRRect[2] = rrect.right;
  skRRect[3] = rrect.bottom;
  skRRect[4] = rrect.tlRadiusX;
  skRRect[5] = rrect.tlRadiusY;
  skRRect[6] = rrect.trRadiusX;
  skRRect[7] = rrect.trRadiusY;
  skRRect[8] = rrect.brRadiusX;
  skRRect[9] = rrect.brRadiusY;
  skRRect[10] = rrect.blRadiusX;
  skRRect[11] = rrect.blRadiusY;
  return skRRect;
}

// TODO(hterkelsen): Use a shared malloc'ed array for performance.
Float32List toOuterSkRect(ui.RRect rrect) {
  final Float32List skRect = Float32List(4);
  skRect[0] = rrect.left;
  skRect[1] = rrect.top;
  skRect[2] = rrect.right;
  skRect[3] = rrect.bottom;
  return skRect;
}

/// Encodes a list of offsets to CanvasKit-compatible point array.
///
/// Uses `CanvasKit.Malloc` to allocate storage for the points in the WASM
/// memory to avoid unnecessary copying. Unless CanvasKit takes ownership of
/// the list the returned list must be explicitly freed using
/// [free].
SkFloat32List toMallocedSkPoints(List<ui.Offset> points) {
  final int len = points.length;
  final SkFloat32List skPoints = mallocFloat32List(len * 2);
  final Float32List list = skPoints.toTypedArray();
  for (int i = 0; i < len; i++) {
    list[2 * i] = points[i].dx;
    list[2 * i + 1] = points[i].dy;
  }
  return skPoints;
}

/// Converts a list of [ui.Offset] into a flat list of points.
Float32List toFlatSkPoints(List<ui.Offset> points) {
  final int len = points.length;
  final Float32List result = Float32List(len * 2);
  for (int i = 0; i < len; i++) {
    result[2 * i] = points[i].dx;
    result[2 * i + 1] = points[i].dy;
  }
  return result;
}

/// Converts a list of [ui.Color] into a flat list of ints.
Uint32List toFlatColors(List<ui.Color> colors) {
  final int len = colors.length;
  final Uint32List result = Uint32List(len);
  for (int i = 0; i < len; i++) {
    result[i] = colors[i].value;
  }
  return result;
}

Uint16List toUint16List(List<int> ints) {
  final int len = ints.length;
  final Uint16List result = Uint16List(len);
  for (int i = 0; i < len; i++) {
    result[i] = ints[i];
  }
  return result;
}

@JS('window.flutterCanvasKit.PictureRecorder')
@staticInterop
class SkPictureRecorder {
  external factory SkPictureRecorder();
}

extension SkPictureRecorderExtension on SkPictureRecorder {
  external SkCanvas beginRecording(Float32List bounds);
  external SkPicture finishRecordingAsPicture();
  external void delete();
}

/// We do not use the `delete` method (which may be removed in the future anyway).
///
/// By Skia coding convention raw pointers should always be treated as
/// "borrowed", i.e. their memory is managed by other objects. In the case of
/// [SkCanvas] it is managed by [SkPictureRecorder].
@JS()
@anonymous
@staticInterop
class SkCanvas {}

extension SkCanvasExtension on SkCanvas {
  external void clear(Float32List color);
  external void clipPath(
    SkPath path,
    SkClipOp clipOp,
    bool doAntiAlias,
  );
  external void clipRRect(
    Float32List rrect,
    SkClipOp clipOp,
    bool doAntiAlias,
  );
  external void clipRect(
    Float32List rrect,
    SkClipOp clipOp,
    bool doAntiAlias,
  );
  external Int32List getDeviceClipBounds();
  external void drawArc(
    Float32List oval,
    double startAngleDegrees,
    double sweepAngleDegrees,
    bool useCenter,
    SkPaint paint,
  );
  external void drawAtlas(
    SkImage image,
    Float32List rects,
    Float32List rstTransforms,
    SkPaint paint,
    SkBlendMode blendMode,
    Uint32List? colors,
  );
  external void drawCircle(
    double x,
    double y,
    double radius,
    SkPaint paint,
  );
  external void drawColorInt(
    double color,
    SkBlendMode blendMode,
  );
  external void drawDRRect(
    Float32List outer,
    Float32List inner,
    SkPaint paint,
  );
  external void drawImageCubic(
    SkImage image,
    double x,
    double y,
    double B,
    double C,
    SkPaint paint,
  );
  external void drawImageOptions(
    SkImage image,
    double x,
    double y,
    SkFilterMode filterMode,
    SkMipmapMode mipmapMode,
    SkPaint paint,
  );
  external void drawImageRectCubic(
    SkImage image,
    Float32List src,
    Float32List dst,
    double B,
    double C,
    SkPaint paint,
  );
  external void drawImageRectOptions(
    SkImage image,
    Float32List src,
    Float32List dst,
    SkFilterMode filterMode,
    SkMipmapMode mipmapMode,
    SkPaint paint,
  );
  external void drawImageNine(
    SkImage image,
    Float32List center,
    Float32List dst,
    SkFilterMode filterMode,
    SkPaint paint,
  );
  external void drawLine(
    double x1,
    double y1,
    double x2,
    double y2,
    SkPaint paint,
  );
  external void drawOval(
    Float32List rect,
    SkPaint paint,
  );
  external void drawPaint(
    SkPaint paint,
  );
  external void drawPath(
    SkPath path,
    SkPaint paint,
  );
  external void drawPoints(
    SkPointMode pointMode,
    Float32List points,
    SkPaint paint,
  );
  external void drawRRect(
    Float32List rrect,
    SkPaint paint,
  );
  external void drawRect(
    Float32List rrect,
    SkPaint paint,
  );
  external void drawShadow(
    SkPath path,
    Float32List zPlaneParams,
    Float32List lightPos,
    double lightRadius,
    Float32List ambientColor,
    Float32List spotColor,
    double flags,
  );
  external void drawVertices(
    SkVertices vertices,
    SkBlendMode blendMode,
    SkPaint paint,
  );
  external double save();
  external double getSaveCount();
  external void saveLayer(
    SkPaint? paint,
    Float32List? bounds,
    SkImageFilter? backdrop,
    int? flags,
  );
  external void restore();
  external void restoreToCount(double count);
  external void rotate(
    double angleDegrees,
    double px,
    double py,
  );
  external void scale(double x, double y);
  external void skew(double x, double y);
  external void concat(Float32List matrix);
  external void translate(double x, double y);
  external List<dynamic> getLocalToDevice();
  external void drawPicture(SkPicture picture);
  external void drawParagraph(
    SkParagraph paragraph,
    double x,
    double y,
  );
}

@JS()
@anonymous
@staticInterop
class SkPicture {}

extension SkPictureExtension on SkPicture {
  external void delete();
}

@JS()
@anonymous
@staticInterop
class SkParagraphBuilderNamespace {}

extension SkParagraphBuilderNamespaceExtension on SkParagraphBuilderNamespace {
  external SkParagraphBuilder MakeFromFontProvider(
    SkParagraphStyle paragraphStyle,
    TypefaceFontProvider? fontManager,
  );
}

@JS()
@anonymous
@staticInterop
class SkParagraphBuilder {}

extension SkParagraphBuilderExtension on SkParagraphBuilder {
  external void addText(String text);
  external void pushStyle(SkTextStyle textStyle);
  external void pushPaintStyle(
      SkTextStyle textStyle, SkPaint foreground, SkPaint background);
  external void pop();
  external void addPlaceholder(
    double width,
    double height,
    SkPlaceholderAlignment alignment,
    SkTextBaseline baseline,
    double offset,
  );

  @JS('getText')
  external String getTextUtf8();
  // SkParagraphBuilder.getText() returns a utf8 string, we need to decode it
  // into a utf16 string.
  String getText() => utf8.decode(getTextUtf8().codeUnits);

  external void setWordsUtf8(Uint32List words);
  external void setWordsUtf16(Uint32List words);
  external void setGraphemeBreaksUtf8(Uint32List graphemes);
  external void setGraphemeBreaksUtf16(Uint32List graphemes);
  external void setLineBreaksUtf8(Uint32List lineBreaks);
  external void setLineBreaksUtf16(Uint32List lineBreaks);

  external SkParagraph build();
  external void delete();
}

@JS()
@anonymous
@staticInterop
class SkParagraphStyle {}

@JS()
@anonymous
@staticInterop
class SkParagraphStyleProperties {
  external factory SkParagraphStyleProperties();
}

extension SkParagraphStylePropertiesExtension on SkParagraphStyleProperties {
  external set textAlign(SkTextAlign? value);
  external set textDirection(SkTextDirection? value);
  external set heightMultiplier(double? value);
  external set textHeightBehavior(SkTextHeightBehavior? value);
  external set maxLines(int? value);
  external set ellipsis(String? value);
  external set textStyle(SkTextStyleProperties? value);
  external set strutStyle(SkStrutStyleProperties? strutStyle);
  external set replaceTabCharacters(bool? bool);
}

@JS()
@staticInterop
class SkTextStyle {}

@JS()
@staticInterop
class SkTextDecorationStyleEnum {}

extension SkTextDecorationStyleEnumExtension on SkTextDecorationStyleEnum {
  external SkTextDecorationStyle get Solid;
  external SkTextDecorationStyle get Double;
  external SkTextDecorationStyle get Dotted;
  external SkTextDecorationStyle get Dashed;
  external SkTextDecorationStyle get Wavy;
}

@JS()
@staticInterop
class SkTextDecorationStyle {}

extension SkTextDecorationStyleExtension on SkTextDecorationStyle {
  external double get value;
}

final List<SkTextDecorationStyle> _skTextDecorationStyles =
    <SkTextDecorationStyle>[
  canvasKit.DecorationStyle.Solid,
  canvasKit.DecorationStyle.Double,
  canvasKit.DecorationStyle.Dotted,
  canvasKit.DecorationStyle.Dashed,
  canvasKit.DecorationStyle.Wavy,
];

SkTextDecorationStyle toSkTextDecorationStyle(ui.TextDecorationStyle style) {
  return _skTextDecorationStyles[style.index];
}

@JS()
@staticInterop
class SkTextBaselineEnum {}

extension SkTextBaselineEnumExtension on SkTextBaselineEnum {
  external SkTextBaseline get Alphabetic;
  external SkTextBaseline get Ideographic;
}

@JS()
@staticInterop
class SkTextBaseline {}

extension SkTextBaselineExtension on SkTextBaseline {
  external double get value;
}

final List<SkTextBaseline> _skTextBaselines = <SkTextBaseline>[
  canvasKit.TextBaseline.Alphabetic,
  canvasKit.TextBaseline.Ideographic,
];

SkTextBaseline toSkTextBaseline(ui.TextBaseline baseline) {
  return _skTextBaselines[baseline.index];
}

@JS()
@staticInterop
class SkPlaceholderAlignmentEnum {}

extension SkPlaceholderAlignmentEnumExtension on SkPlaceholderAlignmentEnum {
  external SkPlaceholderAlignment get Baseline;
  external SkPlaceholderAlignment get AboveBaseline;
  external SkPlaceholderAlignment get BelowBaseline;
  external SkPlaceholderAlignment get Top;
  external SkPlaceholderAlignment get Bottom;
  external SkPlaceholderAlignment get Middle;
}

@JS()
@staticInterop
class SkPlaceholderAlignment {}

extension SkPlaceholderAlignmentExtension on SkPlaceholderAlignment {
  external double get value;
}

final List<SkPlaceholderAlignment> _skPlaceholderAlignments =
    <SkPlaceholderAlignment>[
  canvasKit.PlaceholderAlignment.Baseline,
  canvasKit.PlaceholderAlignment.AboveBaseline,
  canvasKit.PlaceholderAlignment.BelowBaseline,
  canvasKit.PlaceholderAlignment.Top,
  canvasKit.PlaceholderAlignment.Bottom,
  canvasKit.PlaceholderAlignment.Middle,
];

SkPlaceholderAlignment toSkPlaceholderAlignment(
    ui.PlaceholderAlignment alignment) {
  return _skPlaceholderAlignments[alignment.index];
}

@JS()
@anonymous
@staticInterop
class SkTextStyleProperties {
  external factory SkTextStyleProperties();
}

extension SkTextStylePropertiesExtension on SkTextStyleProperties {
  external set backgroundColor(Float32List? value);
  external set color(Float32List? value);
  external set foregroundColor(Float32List? value);
  external set decoration(int? value);
  external set decorationThickness(double? value);
  external set decorationColor(Float32List? value);
  external set decorationStyle(SkTextDecorationStyle? value);
  external set textBaseline(SkTextBaseline? value);
  external set fontSize(double? value);
  external set letterSpacing(double? value);
  external set wordSpacing(double? value);
  external set heightMultiplier(double? value);
  external set halfLeading(bool? value);
  external set locale(String? value);
  external set fontFamilies(List<String>? value);
  external set fontStyle(SkFontStyle? value);
  external set shadows(List<SkTextShadow>? value);
  external set fontFeatures(List<SkFontFeature>? value);
  external set fontVariations(List<SkFontVariation>? value);
}

@JS()
@anonymous
@staticInterop
class SkStrutStyleProperties {
  external factory SkStrutStyleProperties();
}

extension SkStrutStylePropertiesExtension on SkStrutStyleProperties {
  external set fontFamilies(List<String>? value);
  external set fontStyle(SkFontStyle? value);
  external set fontSize(double? value);
  external set heightMultiplier(double? value);
  external set halfLeading(bool? value);
  external set leading(double? value);
  external set strutEnabled(bool? value);
  external set forceStrutHeight(bool? value);
}

@JS()
@anonymous
@staticInterop
class SkFontStyle {
  external factory SkFontStyle();
}

extension SkFontStyleExtension on SkFontStyle {
  external set weight(SkFontWeight? value);
  external set slant(SkFontSlant? value);
}

@JS()
@anonymous
@staticInterop
class SkTextShadow {
  external factory SkTextShadow();
}

extension SkTextShadowExtension on SkTextShadow {
  external set color(Float32List? value);
  external set offset(Float32List? value);
  external set blurRadius(double? value);
}

@JS()
@anonymous
@staticInterop
class SkFontFeature {
  external factory SkFontFeature();
}

extension SkFontFeatureExtension on SkFontFeature {
  external set name(String? value);
  external set value(int? value);
}

@JS()
@anonymous
@staticInterop
class SkFontVariation {
  external factory SkFontVariation();
}

extension SkFontVariationExtension on SkFontVariation {
  external set axis(String? value);
  external set value(double? value);
}

@JS()
@anonymous
@staticInterop
class SkTypeface {}

@JS('window.flutterCanvasKit.Font')
@staticInterop
class SkFont {
  external factory SkFont(SkTypeface typeface);
}

extension SkFontExtension on SkFont {
  external Uint16List getGlyphIDs(String text);
  external void getGlyphBounds(
      List<int> glyphs, SkPaint? paint, Uint8List? output);
}

@JS()
@anonymous
@staticInterop
class SkFontMgr {}

extension SkFontMgrExtension on SkFontMgr {
  external String? getFamilyName(double fontId);
  external void delete();
  external SkTypeface? MakeTypefaceFromData(Uint8List font);
}

@JS('window.flutterCanvasKit.TypefaceFontProvider')
@staticInterop
class TypefaceFontProvider extends SkFontMgr {
  external factory TypefaceFontProvider();
}

extension TypefaceFontProviderExtension on TypefaceFontProvider {
  external void registerFont(Uint8List font, String family);
}

@JS()
@anonymous
@staticInterop
class SkLineMetrics {}

extension SkLineMetricsExtension on SkLineMetrics {
  external double get startIndex;
  external double get endIndex;
  external double get endExcludingWhitespaces;
  external double get endIncludingNewline;
  external bool get isHardBreak;
  external double get ascent;
  external double get descent;
  external double get height;
  external double get width;
  external double get left;
  external double get baseline;
  external double get lineNumber;
}

@JS()
@anonymous
@staticInterop
class SkRectWithDirection {}

extension SkRectWithDirectionExtension on SkRectWithDirection {
  external Float32List rect;
  external SkTextDirection dir;
}

@JS()
@anonymous
@staticInterop
class SkParagraph {}

extension SkParagraphExtension on SkParagraph {
  external double getAlphabeticBaseline();
  external bool didExceedMaxLines();
  external double getHeight();
  external double getIdeographicBaseline();
  external /* List<SkLineMetrics> */ List<Object?> getLineMetrics();
  external double getLongestLine();
  external double getMaxIntrinsicWidth();
  external double getMinIntrinsicWidth();
  external double getMaxWidth();
  external /* List<SkRectWithDirection> */ List<Object?> getRectsForRange(
    double start,
    double end,
    SkRectHeightStyle heightStyle,
    SkRectWidthStyle widthStyle,
  );
  external /* List<SkRectWithDirection> */ List<Object?> getRectsForPlaceholders();
  external SkTextPosition getGlyphPositionAtCoordinate(
    double x,
    double y,
  );
  external SkTextRange getWordBoundary(double position);
  external void layout(double width);
  external void delete();
}

@JS()
@staticInterop
class SkTextPosition {}

extension SkTextPositionExtnsion on SkTextPosition {
  external SkAffinity get affinity;
  external double get pos;
}

@JS()
@staticInterop
class SkTextRange {}

extension SkTextRangeExtension on SkTextRange {
  external double get start;
  external double get end;
}

@JS()
@anonymous
@staticInterop
class SkVertices {}

extension SkVerticesExtension on SkVertices {
  external void delete();
}

@JS()
@anonymous
@staticInterop
class SkTonalColors {
  external factory SkTonalColors({
    required Float32List ambient,
    required Float32List spot,
  });
}

extension SkTonalColorsExtension on SkTonalColors {
  external Float32List get ambient;
  external Float32List get spot;
}

@JS()
@staticInterop
class SkFontMgrNamespace {}

extension SkFontMgrNamespaceExtension on SkFontMgrNamespace {
  // TODO(yjbanov): can this be made non-null? It returns null in our unit-tests right now.
  external SkFontMgr? FromData(List<Uint8List> fonts);
}

@JS()
@staticInterop
class TypefaceFontProviderNamespace {}

extension TypefaceFontProviderNamespaceExtension on TypefaceFontProviderNamespace {
  external TypefaceFontProvider Make();
}

@JS()
@anonymous
@staticInterop
class SkTypefaceFactory {}

extension SkTypefaceFactoryExtension on SkTypefaceFactory {
  external SkTypeface? MakeFreeTypeFaceFromData(ByteBuffer fontData);
}

/// Collects Skia objects that are no longer necessary.
abstract class Collector {
  /// The production collector implementation.
  static final Collector _productionInstance = ProductionCollector();

  /// The collector implementation currently in use.
  static Collector get instance => _instance;
  static Collector _instance = _productionInstance;

  /// In tests overrides the collector implementation.
  static void debugOverrideCollector(Collector override) {
    _instance = override;
  }

  /// In tests restores the collector to the production implementation.
  static void debugRestoreCollector() {
    _instance = _productionInstance;
  }

  /// Registers a [deletable] for collection when the [wrapper] object is
  /// garbage collected.
  ///
  /// The [debugLabel] is used to track the origin of the deletable.
  void register(Object wrapper, SkDeletable deletable);

  /// Deletes the [deletable].
  ///
  /// The exact timing of the deletion is implementation-specific. For example,
  /// a production implementation may want to batch deletables and schedule a
  /// timer to collect them instead of deleting right away.
  ///
  /// A test implementation may want a collection strategy that's less efficient
  /// but more predictable.
  void collect(SkDeletable deletable);
}

/// Uses the browser's real `FinalizationRegistry` to collect objects.
///
/// Uses timers to delete objects in batches and outside the animation frame.
class ProductionCollector implements Collector {
  ProductionCollector() {
    _skObjectFinalizationRegistry =
        SkObjectFinalizationRegistry(allowInterop((SkDeletable deletable) {
      // This is called when GC decides to collect the wrapper object and
      // notify us, which may happen after the object is already deleted
      // explicitly, e.g. when its ref count drops to zero. When that happens
      // skip collection of this object.
      if (!deletable.isDeleted()) {
        collect(deletable);
      }
    }));
  }

  late final SkObjectFinalizationRegistry _skObjectFinalizationRegistry;
  List<SkDeletable> _skiaObjectCollectionQueue = <SkDeletable>[];
  Timer? _skiaObjectCollectionTimer;

  @override
  void register(Object wrapper, SkDeletable deletable) {
    if (Instrumentation.enabled) {
      Instrumentation.instance.incrementCounter(
        '${deletable.constructor.name} registered',
      );
    }
    _skObjectFinalizationRegistry.register(wrapper, deletable);
  }

  /// Schedules a Skia object for deletion in an asap timer.
  ///
  /// A timer is used for the following reasons:
  ///
  ///  - Deleting the object immediately may lead to dangling pointer as the Skia
  ///    object may still be used by a function in the current frame. For example,
  ///    a `CkPaint` + `SkPaint` pair may be created by the framework, passed to
  ///    the engine, and the `CkPaint` dropped immediately. Because GC can kick in
  ///    any time, including in the middle of the event, we may delete `SkPaint`
  ///    prematurely.
  ///  - A microtask, while solves the problem above, would prevent the event from
  ///    yielding to the graphics system to render the frame on the screen if there
  ///    is a large number of objects to delete, causing jank.
  ///
  /// Because scheduling a timer is expensive, the timer is shared by all objects
  /// deleted this frame. No timer is created if no objects were scheduled for
  /// deletion.
  @override
  void collect(SkDeletable deletable) {
    assert(
      !deletable.isDeleted(),
      'Attempted to delete an already deleted Skia object.',
    );
    _skiaObjectCollectionQueue.add(deletable);

    _skiaObjectCollectionTimer ??= Timer(Duration.zero, () {
      // Null out the timer so we can schedule a new one next time objects are
      // scheduled for deletion.
      _skiaObjectCollectionTimer = null;
      collectSkiaObjectsNow();
    });
  }

  /// Deletes all Skia objects pending deletion synchronously.
  ///
  /// After calling this method [_skiaObjectCollectionQueue] is empty.
  ///
  /// Throws a [SkiaObjectCollectionError] if CanvasKit fails to delete at least
  /// one object. The error is populated with information about the first failed
  /// object. Upon an error the collection continues and the collection queue is
  /// emptied out to prevent memory leaks. This may happen, for example, when the
  /// same object is deleted more than once.
  void collectSkiaObjectsNow() {
    domWindow.performance.mark('SkObject collection-start');
    final int length = _skiaObjectCollectionQueue.length;
    dynamic firstError;
    StackTrace? firstStackTrace;
    for (int i = 0; i < length; i++) {
      final SkDeletable deletable = _skiaObjectCollectionQueue[i];
      if (deletable.isDeleted()) {
        // Some Skia objects are ref counted and are deleted before GC and/or
        // the collection timer begins collecting them. So we have to check
        // again if the objects is worth collecting.
        continue;
      }
      if (Instrumentation.enabled) {
        Instrumentation.instance.incrementCounter(
          '${deletable.constructor.name} deleted',
        );
      }
      try {
        deletable.delete();
      } catch (error, stackTrace) {
        // Remember the error, but keep going. If for some reason CanvasKit fails
        // to delete an object we still want to delete other objects and empty
        // out the queue. Otherwise, the queue will never be flushed and keep
        // accumulating objects, a.k.a. memory leak.
        if (firstError == null) {
          firstError = error;
          firstStackTrace = stackTrace;
        }
      }
    }
    _skiaObjectCollectionQueue = <SkDeletable>[];

    domWindow.performance.mark('SkObject collection-end');
    domWindow.performance.measure('SkObject collection',
        'SkObject collection-start', 'SkObject collection-end');

    // It's safe to throw the error here, now that we've processed the queue.
    if (firstError != null) {
      throw SkiaObjectCollectionError(firstError, firstStackTrace);
    }
  }
}

/// Thrown by [ProductionCollector] when Skia object collection fails.
class SkiaObjectCollectionError implements Error {
  SkiaObjectCollectionError(this.error, this.stackTrace);

  final dynamic error;

  @override
  final StackTrace? stackTrace;

  @override
  String toString() => 'SkiaObjectCollectionError: $error\n$stackTrace';
}

/// Any Skia object that has a `delete` method.
@JS()
@anonymous
@staticInterop
class SkDeletable {}

extension SkDeletableExtension on SkDeletable {
  /// Deletes the C++ side object.
  external void delete();

  /// Returns whether the correcponding C++ object has been deleted.
  external bool isDeleted();

  /// Returns the JavaScript constructor for this object.
  ///
  /// This is useful for debugging.
  external JsConstructor get constructor;
}

@JS()
@anonymous
@staticInterop
class JsConstructor {}

extension JsConstructorExtension on JsConstructor {
  /// The name of the "constructor", typically the function name called with
  /// the `new` keyword, or the ES6 class name.
  ///
  /// This is useful for debugging.
  external String get name;
}

/// Attaches a weakly referenced object to another object and calls a finalizer
/// with the latter when weakly referenced object is garbage collected.
///
/// We use this to delete Skia objects when their "Ck" wrapper is garbage
/// collected.
///
/// Example sequence of events:
///
/// 1. A (CkPaint, SkPaint) pair created.
/// 2. The paint is used to paint some picture.
/// 3. CkPaint is dropped by the app.
/// 4. GC decides to perform a GC cycle and collects CkPaint.
/// 5. The finalizer function is called with the SkPaint as the sole argument.
/// 6. We call `delete` on SkPaint.
@JS('window.FinalizationRegistry')
@staticInterop
class SkObjectFinalizationRegistry {
  // TODO(hterkelsen): Add a type for the `cleanup` function when
  // native constructors support type parameters.
  external factory SkObjectFinalizationRegistry(Function cleanup);
}

extension SkObjectFinalizationRegistryExtension on SkObjectFinalizationRegistry {
  external void register(Object ckObject, Object skObject);
}

@JS('window.FinalizationRegistry')
external Object? get _finalizationRegistryConstructor;

/// Whether the current browser supports `FinalizationRegistry`.
bool browserSupportsFinalizationRegistry =
    _finalizationRegistryConstructor != null;

/// Sets the value of [browserSupportsFinalizationRegistry] to its true value.
void debugResetBrowserSupportsFinalizationRegistry() {
  browserSupportsFinalizationRegistry =
      _finalizationRegistryConstructor != null;
}

@JS()
@staticInterop
class SkData {}

extension SkDataExtension on SkData {
  external double size();
  external bool isEmpty();
  external Uint8List bytes();
  external void delete();
}

@JS()
@anonymous
@staticInterop
class SkImageInfo {
  external factory SkImageInfo({
    required double width,
    required double height,
    required SkColorType colorType,
    required SkAlphaType alphaType,
    required ColorSpace colorSpace,
  });
}

extension SkImageInfoExtension on SkImageInfo {
  external SkAlphaType get alphaType;
  external ColorSpace get colorSpace;
  external SkColorType get colorType;
  external double get height;
  external bool get isEmpty;
  external bool get isOpaque;
  external Float32List get bounds;
  external double get width;
  external SkImageInfo makeAlphaType(SkAlphaType alphaType);
  external SkImageInfo makeColorSpace(ColorSpace colorSpace);
  external SkImageInfo makeColorType(SkColorType colorType);
  external SkImageInfo makeWH(double width, double height);
}

@JS()
@anonymous
@staticInterop
class SkPartialImageInfo {
  external factory SkPartialImageInfo({
    required double width,
    required double height,
    required SkColorType colorType,
    required SkAlphaType alphaType,
    required ColorSpace colorSpace,
  });
}

extension SkPartialImageInfoExtension on SkPartialImageInfo {
  external SkAlphaType get alphaType;
  external ColorSpace get colorSpace;
  external SkColorType get colorType;
  external double get height;
  external double get width;
}

/// Helper interop methods for [patchCanvasKitModule].
@JS()
external set _flutterWebCachedModule(Object? module);

@JS()
external Object? get _flutterWebCachedModule;

@JS()
external set _flutterWebCachedExports(Object? exports);

@JS()
external Object? get _flutterWebCachedExports;

@JS('Object')
external Object get objectConstructor;

@JS()
external Object? get exports;

@JS()
external Object? get module;

@JS('window.flutterCanvasKit.RuntimeEffect')
@anonymous
@staticInterop
class SkRuntimeEffect {}

@JS('window.flutterCanvasKit.RuntimeEffect.Make')
external SkRuntimeEffect? MakeRuntimeEffect(String program);

extension SkSkRuntimeEffectExtension on SkRuntimeEffect {
  external SkShader? makeShader(List<Object> uniforms);
  external SkShader? makeShaderWithChildren(List<Object> uniforms, List<Object?> children);
}

/// Monkey-patch the top-level `module` and `exports` objects so that
/// CanvasKit doesn't attempt to register itself as an anonymous module.
///
/// The idea behind making these fake `exports` and `module` objects is
/// that `canvaskit.js` contains the following lines of code:
///
///     if (typeof exports === 'object' && typeof module === 'object')
///       module.exports = CanvasKitInit;
///     else if (typeof define === 'function' && define['amd'])
///       define([], function() { return CanvasKitInit; });
///
/// We need to avoid hitting the case where CanvasKit defines an anonymous
/// module, since this breaks RequireJS, which DDC and some plugins use.
/// Temporarily removing the `define` function won't work because RequireJS
/// could load in between this code running and the CanvasKit code running.
/// Also, we cannot monkey-patch the `define` function because it is
/// non-configurable (it is a top-level 'var').
// TODO(hterkelsen): Rather than this monkey-patch hack, we should
// build CanvasKit ourselves. See:
// https://github.com/flutter/flutter/issues/52588
void patchCanvasKitModule(DomHTMLScriptElement canvasKitScript) {
  // First check if `exports` and `module` are already defined. If so, then
  // CommonJS is being used, and we shouldn't have any problems.
  if (exports == null) {
    final Object? exportsAccessor = js_util.jsify(<String, dynamic>{
      'get': allowInterop(() {
        if (domDocument.currentScript == canvasKitScript) {
          return objectConstructor;
        } else {
          return _flutterWebCachedExports;
        }
      }),
      'set': allowInterop((dynamic value) {
        _flutterWebCachedExports = value;
      }),
      'configurable': true,
    });
    js_util.callMethod(objectConstructor,
        'defineProperty', <dynamic>[domWindow, 'exports', exportsAccessor]);
  }
  if (module == null) {
    final Object? moduleAccessor = js_util.jsify(<String, dynamic>{
      'get': allowInterop(() {
        if (domDocument.currentScript == canvasKitScript) {
          return objectConstructor;
        } else {
          return _flutterWebCachedModule;
        }
      }),
      'set': allowInterop((dynamic value) {
        _flutterWebCachedModule = value;
      }),
      'configurable': true,
    });
    js_util.callMethod(objectConstructor,
        'defineProperty', <dynamic>[domWindow, 'module', moduleAccessor]);
  }
}

String get _canvasKitBaseUrl => configuration.canvasKitBaseUrl;

const String _kFullCanvasKitJsFileName = 'canvaskit.js';
const String _kChromiumCanvasKitJsFileName = 'chromium/canvaskit.js';

// TODO(mdebbar): Replace this with a Record once it's supported in Dart.
class _CanvasKitVariantUrl {
  const _CanvasKitVariantUrl(this.url, this.variant)
      : assert(
          variant != CanvasKitVariant.auto,
          'CanvasKitVariant.auto cannot have a url',
        );

  final String url;
  final CanvasKitVariant variant;

  static _CanvasKitVariantUrl chromium = _CanvasKitVariantUrl(
    '$_canvasKitBaseUrl$_kChromiumCanvasKitJsFileName',
    CanvasKitVariant.chromium,
  );

  static _CanvasKitVariantUrl full = _CanvasKitVariantUrl(
    '$_canvasKitBaseUrl$_kFullCanvasKitJsFileName',
    CanvasKitVariant.full,
  );
}

List<_CanvasKitVariantUrl> get _canvasKitUrls {
  switch (configuration.canvasKitVariant) {
    case CanvasKitVariant.auto:
      return <_CanvasKitVariantUrl>[
        if (browserSupportsCanvaskitChromium) _CanvasKitVariantUrl.chromium,
        _CanvasKitVariantUrl.full,
      ];
    case CanvasKitVariant.full:
      return <_CanvasKitVariantUrl>[_CanvasKitVariantUrl.full];
    case CanvasKitVariant.chromium:
      return <_CanvasKitVariantUrl>[_CanvasKitVariantUrl.chromium];
  }
}

@visibleForTesting
String canvasKitWasmModuleUrl(String file, String canvasKitBase) =>
    canvasKitBase + file;

/// Download and initialize the CanvasKit module.
///
/// Downloads the CanvasKit JavaScript, then calls `CanvasKitInit` to download
/// and intialize the CanvasKit wasm.
Future<CanvasKit> downloadCanvasKit() async {
  await _downloadOneOf(_canvasKitUrls);

  return CanvasKitInit(CanvasKitInitOptions(
    locateFile: allowInterop(canvasKitWasmModuleUrl),
  ));
}

/// Finds the first entry in [urls] that can be downloaded successfully, and
/// downloads it.
///
/// If none of the URLs can be downloaded, throws an [Exception].
///
/// Also sets [canvasKitVariant] to the variant of CanvasKit that was downloaded.
Future<void> _downloadOneOf(Iterable<_CanvasKitVariantUrl> urls) async {
  for (final _CanvasKitVariantUrl entry in urls) {
    if (await _downloadCanvasKitJs(entry.url)) {
      canvasKitVariant = entry.variant;
      return;
    }
  }

  // Reaching this point means that all URLs failed to download.
  throw Exception(
    'Failed to download any of the following CanvasKit URLs: $urls',
  );
}

/// Downloads the CanvasKit JavaScript file at [url].
///
/// Returns a [Future] that completes with `true` if the CanvasKit JavaScript
/// file was successfully downloaded, or `false` if it failed.
Future<bool> _downloadCanvasKitJs(String url) {
  final DomHTMLScriptElement canvasKitScript = createDomHTMLScriptElement();
  canvasKitScript.src = createTrustedScriptUrl(url);

  final Completer<bool> canvasKitLoadCompleter = Completer<bool>();

  late final DomEventListener loadCallback;
  late final DomEventListener errorCallback;

  void loadEventHandler(DomEvent _) {
    canvasKitScript.remove();
    canvasKitLoadCompleter.complete(true);
  }
  void errorEventHandler(DomEvent errorEvent) {
    canvasKitScript.remove();
    canvasKitLoadCompleter.complete(false);
  }

  loadCallback = allowInterop(loadEventHandler);
  errorCallback = allowInterop(errorEventHandler);

  canvasKitScript.addEventListener('load', loadCallback);
  canvasKitScript.addEventListener('error', errorCallback);

  patchCanvasKitModule(canvasKitScript);
  domDocument.head!.appendChild(canvasKitScript);

  return canvasKitLoadCompleter.future;
}