// Copyright (c) Six Labors.
// Licensed under the Six Labors Split License.

using SixLabors.Fonts.Rendering;
using SixLabors.ImageSharp.Drawing.Processing;
using SixLabors.ImageSharp.PixelFormats;

namespace SixLabors.ImageSharp.Drawing.Text {
  internal static class TextUtilities
  {
      public static IntersectionRule MapFillRule(FillRule fillRule)
          => fillRule switch
          {
              FillRule.EvenOdd => IntersectionRule.EvenOdd,
              FillRule.NonZero => IntersectionRule.NonZero,
              _ => IntersectionRule.NonZero,
          };

      public static PixelAlphaCompositionMode MapCompositionMode(CompositeMode mode)
          => mode switch
          {
              CompositeMode.Clear => PixelAlphaCompositionMode.Clear,
              CompositeMode.Src => PixelAlphaCompositionMode.Src,
              CompositeMode.Dest => PixelAlphaCompositionMode.Dest,
              CompositeMode.SrcOver => PixelAlphaCompositionMode.SrcOver,
              CompositeMode.DestOver => PixelAlphaCompositionMode.DestOver,
              CompositeMode.SrcIn => PixelAlphaCompositionMode.SrcIn,
              CompositeMode.DestIn => PixelAlphaCompositionMode.DestIn,
              CompositeMode.SrcOut => PixelAlphaCompositionMode.SrcOut,
              CompositeMode.DestOut => PixelAlphaCompositionMode.DestOut,
              CompositeMode.SrcAtop => PixelAlphaCompositionMode.SrcAtop,
              CompositeMode.DestAtop => PixelAlphaCompositionMode.DestAtop,
              CompositeMode.Xor => PixelAlphaCompositionMode.Xor,
              _ => PixelAlphaCompositionMode.SrcOver,
          };

      public static PixelColorBlendingMode MapBlendingMode(CompositeMode mode)
          => mode switch
          {
              CompositeMode.Plus => PixelColorBlendingMode.Add,
              CompositeMode.Screen => PixelColorBlendingMode.Screen,
              CompositeMode.Overlay => PixelColorBlendingMode.Overlay,
              CompositeMode.Darken => PixelColorBlendingMode.Darken,
              CompositeMode.Lighten => PixelColorBlendingMode.Lighten,
              CompositeMode.HardLight => PixelColorBlendingMode.HardLight,
              CompositeMode.Multiply => PixelColorBlendingMode.Multiply,

              // TODO: We do not support the following separate alpha blending modes:
              // - ColorDodge, ColorBurn, SoftLight, Difference, Exclusion
              // TODO: We do not support the non-alpha blending modes.
              // - Hue, Saturation, Color, Luminosity
              _ => PixelColorBlendingMode.Normal
          };

      public static DrawingOptions CloneOrReturnForRules(
          this DrawingOptions drawingOptions,
          IntersectionRule intersectionRule,
          PixelAlphaCompositionMode compositionMode,
          PixelColorBlendingMode colorBlendingMode)
      {
          if (drawingOptions.ShapeOptions.IntersectionRule == intersectionRule &&
              drawingOptions.GraphicsOptions.AlphaCompositionMode == compositionMode &&
              drawingOptions.GraphicsOptions.ColorBlendingMode == colorBlendingMode)
          {
              return drawingOptions;
          }

          ShapeOptions shapeOptions = drawingOptions.ShapeOptions.DeepClone();
          shapeOptions.IntersectionRule = intersectionRule;

          GraphicsOptions graphicsOptions = drawingOptions.GraphicsOptions.DeepClone();
          graphicsOptions.AlphaCompositionMode = compositionMode;
          graphicsOptions.ColorBlendingMode = colorBlendingMode;

          return new DrawingOptions(graphicsOptions, shapeOptions, drawingOptions.Transform);
      }

      public static GraphicsOptions CloneOrReturnForRules(
          this GraphicsOptions graphicsOptions,
          PixelAlphaCompositionMode compositionMode,
          PixelColorBlendingMode colorBlendingMode)
      {
          if (graphicsOptions.AlphaCompositionMode == compositionMode &&
              graphicsOptions.ColorBlendingMode == colorBlendingMode)
          {
              return graphicsOptions;
          }

          GraphicsOptions clone = graphicsOptions.DeepClone();
          clone.AlphaCompositionMode = compositionMode;
          clone.ColorBlendingMode = colorBlendingMode;
          return clone;
      }
  }
}