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

namespace CPF.Mac.CoreFoundation
{
	public abstract class CFStream : CFType, INativeObject, IDisposable
	{
		public class StreamEventArgs : EventArgs
		{
			public CFStreamEventType EventType
			{
				get;
				private set;
			}

			public StreamEventArgs(CFStreamEventType type)
			{
				EventType = type;
			}

			public override string ToString()
			{
				return $"[StreamEventArgs: EventType={EventType}]";
			}
		}

		protected delegate void CFStreamCallback(IntPtr s, CFStreamEventType type, IntPtr info);

		private IntPtr handle;

		private GCHandle gch;

		private CFRunLoop loop;

		private NSString loopMode;

		private bool open;

		private bool closed;

		public IntPtr Handle => handle;

		public event EventHandler<StreamEventArgs> OpenCompletedEvent;

		public event EventHandler<StreamEventArgs> HasBytesAvailableEvent;

		public event EventHandler<StreamEventArgs> CanAcceptBytesEvent;

		public event EventHandler<StreamEventArgs> ErrorEvent;

		public event EventHandler<StreamEventArgs> ClosedEvent;

		[DllImport("/System/Library/Frameworks/CoreFoundation.framework/CoreFoundation")]
		private static extern void CFStreamCreatePairWithSocket(IntPtr allocator, CFSocketNativeHandle socket, out IntPtr read, out IntPtr write);

		[DllImport("/System/Library/Frameworks/CoreServices.framework/Frameworks/CFNetwork.framework/CFNetwork")]
		private static extern void CFStreamCreatePairWithSocketToHost(IntPtr allocator, IntPtr host, int port, out IntPtr read, out IntPtr write);

		public static void CreatePairWithSocketToHost(string host, int port, out CFReadStream readStream, out CFWriteStream writeStream)
		{
			using (CFString cFString = new CFString(host))
			{
				CFStreamCreatePairWithSocketToHost(IntPtr.Zero, cFString.Handle, port, out IntPtr read, out IntPtr write);
				readStream = new CFReadStream(read);
				writeStream = new CFWriteStream(write);
			}
		}

		[DllImport("/System/Library/Frameworks/CoreServices.framework/Frameworks/CFNetwork.framework/CFNetwork")]
		private static extern IntPtr CFReadStreamCreateForHTTPRequest(IntPtr alloc, IntPtr request);

		public static CFHTTPStream CreateForHTTPRequest(CFHTTPMessage request)
		{
			IntPtr value = CFReadStreamCreateForHTTPRequest(IntPtr.Zero, request.Handle);
			if (value == IntPtr.Zero)
			{
				return null;
			}
			return new CFHTTPStream(value);
		}

		[DllImport("/System/Library/Frameworks/CoreServices.framework/Frameworks/CFNetwork.framework/CFNetwork")]
		private static extern IntPtr CFReadStreamCreateForStreamedHTTPRequest(IntPtr alloc, IntPtr request, IntPtr body);

		public static CFHTTPStream CreateForStreamedHTTPRequest(CFHTTPMessage request, CFReadStream body)
		{
			IntPtr value = CFReadStreamCreateForStreamedHTTPRequest(IntPtr.Zero, request.Handle, body.Handle);
			if (value == IntPtr.Zero)
			{
				return null;
			}
			return new CFHTTPStream(value);
		}

		[DllImport("/System/Library/Frameworks/CoreServices.framework/Frameworks/CFNetwork.framework/CFNetwork")]
		private static extern void CFStreamCreateBoundPair(IntPtr alloc, out IntPtr readStream, out IntPtr writeStream, CFIndex transferBufferSize);

		public static void CreateBoundPair(out CFReadStream readStream, out CFWriteStream writeStream, int bufferSize)
		{
			CFStreamCreateBoundPair(IntPtr.Zero, out IntPtr readStream2, out IntPtr writeStream2, bufferSize);
			readStream = new CFReadStream(readStream2);
			writeStream = new CFWriteStream(writeStream2);
		}

		public abstract CFException GetError();

		protected void CheckError()
		{
			CFException error = GetError();
			if (error != null)
			{
				throw error;
			}
		}

		public void Open()
		{
			if (open || closed)
			{
				throw new InvalidOperationException();
			}
			CheckHandle();
			if (!DoOpen())
			{
				CheckError();
				throw new InvalidOperationException();
			}
			open = true;
		}

		protected abstract bool DoOpen();

		public void Close()
		{
			if (open)
			{
				CheckHandle();
				if (loop != null)
				{
					DoSetClient(null, 0, IntPtr.Zero);
					UnscheduleFromRunLoop(loop, loopMode);
					loop = null;
					loopMode = null;
				}
				try
				{
					DoClose();
				}
				finally
				{
					open = false;
					closed = true;
				}
			}
		}

		protected abstract void DoClose();

		public CFStreamStatus GetStatus()
		{
			CheckHandle();
			return DoGetStatus();
		}

		protected abstract CFStreamStatus DoGetStatus();

		internal IntPtr GetProperty(NSString name)
		{
			CheckHandle();
			return DoGetProperty(name);
		}

		protected abstract IntPtr DoGetProperty(NSString name);

		protected abstract bool DoSetProperty(NSString name, INativeObject value);

		internal void SetProperty(NSString name, INativeObject value)
		{
			CheckHandle();
			if (DoSetProperty(name, value))
			{
				return;
			}
			throw new InvalidOperationException($"Cannot set property '{name}' on {GetType().Name}.");
		}

		protected virtual void OnOpenCompleted(StreamEventArgs args)
		{
			if (this.OpenCompletedEvent != null)
			{
				this.OpenCompletedEvent(this, args);
			}
		}

		protected virtual void OnHasBytesAvailableEvent(StreamEventArgs args)
		{
			if (this.HasBytesAvailableEvent != null)
			{
				this.HasBytesAvailableEvent(this, args);
			}
		}

		protected virtual void OnCanAcceptBytesEvent(StreamEventArgs args)
		{
			if (this.CanAcceptBytesEvent != null)
			{
				this.CanAcceptBytesEvent(this, args);
			}
		}

		protected virtual void OnErrorEvent(StreamEventArgs args)
		{
			if (this.ErrorEvent != null)
			{
				this.ErrorEvent(this, args);
			}
		}

		protected virtual void OnClosedEvent(StreamEventArgs args)
		{
			if (this.ClosedEvent != null)
			{
				this.ClosedEvent(this, args);
			}
		}

		protected abstract void ScheduleWithRunLoop(CFRunLoop loop, NSString mode);

		protected abstract void UnscheduleFromRunLoop(CFRunLoop loop, NSString mode);

		[MonoPInvokeCallback(typeof(CFStreamCallback))]
		private static void OnCallback(IntPtr s, CFStreamEventType type, IntPtr info)
		{
			(GCHandle.FromIntPtr(info).Target as CFStream).OnCallback(type);
		}

		protected virtual void OnCallback(CFStreamEventType type)
		{
			StreamEventArgs args = new StreamEventArgs(type);
			switch (type)
			{
			case CFStreamEventType.OpenCompleted:
				OnOpenCompleted(args);
				break;
			case CFStreamEventType.CanAcceptBytes:
				OnCanAcceptBytesEvent(args);
				break;
			case CFStreamEventType.HasBytesAvailable:
				OnHasBytesAvailableEvent(args);
				break;
			case CFStreamEventType.ErrorOccurred:
				OnErrorEvent(args);
				break;
			case CFStreamEventType.EndEncountered:
				OnClosedEvent(args);
				break;
			}
		}

		public void EnableEvents(CFRunLoop runLoop, NSString runLoopMode)
		{
			if (open || closed || loop != null)
			{
				throw new InvalidOperationException();
			}
			CheckHandle();
			loop = runLoop;
			loopMode = runLoopMode;
			CFStreamClientContext structure = default(CFStreamClientContext);
			structure.Info = GCHandle.ToIntPtr(gch);
			CFStreamEventType value = CFStreamEventType.OpenCompleted | CFStreamEventType.HasBytesAvailable | CFStreamEventType.CanAcceptBytes | CFStreamEventType.ErrorOccurred | CFStreamEventType.EndEncountered;
			IntPtr intPtr = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(CFStreamClientContext)));
			try
			{
				Marshal.StructureToPtr(structure, intPtr, fDeleteOld: false);
				if (!DoSetClient(OnCallback, (int)value, intPtr))
				{
					throw new InvalidOperationException("Stream does not support async events.");
				}
			}
			finally
			{
				Marshal.FreeHGlobal(intPtr);
			}
			ScheduleWithRunLoop(runLoop, runLoopMode);
		}

		protected abstract bool DoSetClient(CFStreamCallback callback, CFIndex eventTypes, IntPtr context);

		protected CFStream(IntPtr handle)
		{
			this.handle = handle;
			gch = GCHandle.Alloc(this);
		}

		protected void CheckHandle()
		{
			if (handle == IntPtr.Zero)
			{
				throw new ObjectDisposedException(GetType().Name);
			}
		}

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

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

		protected virtual void Dispose(bool disposing)
		{
			if (disposing)
			{
				Close();
				if (gch.IsAllocated)
				{
					gch.Free();
				}
			}
			if (handle != IntPtr.Zero)
			{
				CFObject.CFRelease(handle);
				handle = IntPtr.Zero;
			}
		}
	}
}