using CPF.Mac.Foundation;
using CPF.Mac.ObjCRuntime;
using System;
using System.Runtime.InteropServices;

namespace CPF.Mac.CoreGraphics
{
	public class CGLayer : INativeObject, IDisposable
	{
		private IntPtr handle;

		public IntPtr Handle => handle;

		public CGSize Size => CGLayerGetSize(handle);

		public CGContext Context => new CGContext(CGLayerGetContext(handle));

		internal CGLayer(IntPtr handle)
		{
			if (handle == IntPtr.Zero)
			{
				throw new Exception("Invalid parameters to layer creation");
			}
			this.handle = handle;
			CGLayerRetain(handle);
		}

		[Preserve(Conditional = true)]
		internal CGLayer(IntPtr handle, bool owns)
		{
			if (!owns)
			{
				CGLayerRetain(handle);
			}
			this.handle = handle;
		}

		~CGLayer()
		{
			Dispose(disposing: false);
		}

		public void Dispose()
		{
			Dispose(disposing: true);
			GC.SuppressFinalize(this);
		}

		[DllImport("/System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/CoreGraphics.framework/CoreGraphics")]
		private static extern void CGLayerRelease(IntPtr handle);

		[DllImport("/System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/CoreGraphics.framework/CoreGraphics")]
		private static extern void CGLayerRetain(IntPtr handle);

		protected virtual void Dispose(bool disposing)
		{
			if (handle != IntPtr.Zero)
			{
				CGLayerRelease(handle);
				handle = IntPtr.Zero;
			}
		}

		[DllImport("/System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/CoreGraphics.framework/CoreGraphics")]
		private static extern CGSize CGLayerGetSize(IntPtr layer);

		[DllImport("/System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/CoreGraphics.framework/CoreGraphics")]
		private static extern IntPtr CGLayerGetContext(IntPtr layer);

		[DllImport("/System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/CoreGraphics.framework/CoreGraphics")]
		private static extern IntPtr CGLayerCreateWithContext(IntPtr context, CGSize size, IntPtr dictionary);

		public static CGLayer Create(CGContext context, CGSize size)
		{
			return new CGLayer(CGLayerCreateWithContext(context.Handle, size, IntPtr.Zero), owns: true);
		}
	}
}
