using System;
using System.Diagnostics;
using SkiaSharp;
using Svg.Skia;
 
namespace Microsoft.Maui.Resizetizer
{
	internal class SkiaSharpSvgTools : SkiaSharpTools, IDisposable
	{
		SKSvg svg;
 
		public SkiaSharpSvgTools(ResizeImageInfo info, ILogger logger)
			: this(info.Filename, info.BaseSize, info.Color, info.TintColor, logger)
		{
		}
 
		public SkiaSharpSvgTools(string filename, SKSize? baseSize, SKColor? backgroundColor, SKColor? tintColor, ILogger logger)
			: base(filename, baseSize, backgroundColor, tintColor, logger)
		{
			var sw = new Stopwatch();
			sw.Start();
 
			svg = new SKSvg();
			var pic = svg.Load(filename);
 
			sw.Stop();
			Logger?.Log($"Open SVG took {sw.ElapsedMilliseconds}ms ({filename})");
 
			if (pic.CullRect.Size.IsEmpty)
				Logger?.Log($"SVG picture did not have a size and will fail to generate. ({Filename})");
		}
 
		public override SKSize GetOriginalSize() =>
			svg.Picture.CullRect.Size;
 
		public override void DrawUnscaled(SKCanvas canvas, float scale)
		{
			if (scale >= 1)
			{
				// draw using default scaling
				canvas.DrawPicture(svg.Picture, Paint);
			}
			else
			{
				// draw using raster downscaling
				var size = GetOriginalSize();
 
				// vector scaling has rounding issues, so first draw as intended
				var info = new SKImageInfo((int)size.Width, (int)size.Height);
				using var bmp = new SKBitmap(info);
				using var cvn = new SKCanvas(bmp);
 
				// draw to a larger canvas first
				cvn.Clear(SKColors.Transparent);
				cvn.DrawPicture(svg.Picture, Paint);
 
				// set the paint to be the highest quality it can find
				var paint = new SKPaint
				{
					IsAntialias = true,
					FilterQuality = SKFilterQuality.High
				};
 
				// draw to the main canvas using the correct quality settings
				canvas.DrawBitmap(bmp, 0, 0, paint);
			}
		}
 
		public void Dispose()
		{
			svg?.Dispose();
			svg = null;
		}
	}
}