using System;
using System.Collections.Generic;
using System.Runtime.InteropServices;

namespace SoundIOSharp
{
	public class SoundIOInStream : IDisposable
	{
		internal SoundIOInStream (Pointer<SoundIoInStream> handle)
		{
			this.handle = handle;
		}

		Pointer<SoundIoInStream> handle;

		public void Dispose ()
		{
			Natives.soundio_instream_destroy (handle);
		}

		// Equality (based on handle)

		public override bool Equals (object other)
		{
			var d = other as SoundIOInStream;
			return d != null && (this.handle == d.handle);
		}

		public override int GetHashCode ()
		{
			return (int)(IntPtr)handle;
		}

		public static bool operator == (SoundIOInStream obj1, SoundIOInStream obj2)
		{
			return (object)obj1 == null ? (object)obj2 == null : obj1.Equals (obj2);
		}

		public static bool operator != (SoundIOInStream obj1, SoundIOInStream obj2)
		{
			return (object)obj1 == null ? (object)obj2 != null : !obj1.Equals (obj2);
		}

		// fields

		public SoundIODevice Device {
			get { return new SoundIODevice (Marshal.ReadIntPtr (handle, device_offset)); }
		}
		static readonly int device_offset = (int)Marshal.OffsetOf<SoundIoInStream> ("device");

		public SoundIOFormat Format {
			get { return (SoundIOFormat) Marshal.ReadInt32 (handle, format_offset); }
			set { Marshal.WriteInt32 (handle, format_offset, (int) value); }
		}
		static readonly int format_offset = (int)Marshal.OffsetOf<SoundIoInStream> ("format");

		public int SampleRate {
			get { return Marshal.ReadInt32 (handle, sample_rate_offset); }
			set { Marshal.WriteInt32 (handle, sample_rate_offset, value); }
		}
		static readonly int sample_rate_offset = (int)Marshal.OffsetOf<SoundIoInStream> ("sample_rate");

		public SoundIOChannelLayout Layout {
			get { return new SoundIOChannelLayout ((IntPtr) handle + layout_offset); }
			set {
				unsafe {
					Buffer.MemoryCopy ((void*) ((IntPtr) handle + layout_offset), (void*)value.Handle,
							   Marshal.SizeOf<SoundIoChannelLayout> (), Marshal.SizeOf<SoundIoChannelLayout> ());
				}
			}
		}
		static readonly int layout_offset = (int)Marshal.OffsetOf<SoundIoInStream> ("layout");


		public double SoftwareLatency {
			get { return MarshalEx.ReadDouble (handle, software_latency_offset); }
			set { MarshalEx.WriteDouble (handle, software_latency_offset, value); }
		}
		static readonly int software_latency_offset = (int)Marshal.OffsetOf<SoundIoInStream> ("software_latency");

		// error_callback
		public Action ErrorCallback {
			get { return error_callback; }
			set {
				error_callback = value;
				error_callback_native = _ => error_callback ();
				var ptr = Marshal.GetFunctionPointerForDelegate (error_callback_native);
				Marshal.WriteIntPtr (handle, error_callback_offset, ptr);
			}
		}
		static readonly int error_callback_offset = (int)Marshal.OffsetOf<SoundIoInStream> ("error_callback");
		Action error_callback;
		delegate void error_callback_delegate (IntPtr handle);
		error_callback_delegate error_callback_native;

		// read_callback
		public Action<int,int> ReadCallback {
			get { return read_callback; }
			set {
				read_callback = value;
				read_callback_native = (_, minFrameCount, maxFrameCount) => read_callback (minFrameCount, maxFrameCount);
				var ptr = Marshal.GetFunctionPointerForDelegate (read_callback_native);
				Marshal.WriteIntPtr (handle, read_callback_offset, ptr);
			}
		}
		static readonly int read_callback_offset = (int)Marshal.OffsetOf<SoundIoInStream> ("read_callback");
		Action<int, int> read_callback;
		delegate void read_callback_delegate (IntPtr handle, int min, int max);
		read_callback_delegate read_callback_native;

		// overflow_callback
		public Action OverflowCallback {
			get { return overflow_callback; }
			set {
				overflow_callback = value;
				overflow_callback_native = _ => overflow_callback ();
				var ptr = Marshal.GetFunctionPointerForDelegate (overflow_callback_native);
				Marshal.WriteIntPtr (handle, overflow_callback_offset, ptr);
			}
		}
		static readonly int overflow_callback_offset = (int)Marshal.OffsetOf<SoundIoInStream> ("overflow_callback");
		Action overflow_callback;
		delegate void overflow_callback_delegate (IntPtr handle);
		overflow_callback_delegate overflow_callback_native;

		// FIXME: this should be taken care in more centralized/decent manner... we don't want to write
		// this kind of code anywhere we need string marshaling.
		List<IntPtr> allocated_hglobals = new List<IntPtr> ();

		public string Name {
			get { return Marshal.PtrToStringAnsi (Marshal.ReadIntPtr (handle, name_offset)); }
			set {
				unsafe {
					var existing = Marshal.ReadIntPtr (handle, name_offset);
					if (allocated_hglobals.Contains (existing)) {
						allocated_hglobals.Remove (existing);
						Marshal.FreeHGlobal (existing);
					}
					var ptr = Marshal.StringToHGlobalAnsi (value);
					Marshal.WriteIntPtr (handle, name_offset, ptr);
					allocated_hglobals.Add (ptr);
				}
			}
		}
		static readonly int name_offset = (int)Marshal.OffsetOf<SoundIoInStream> ("name");

		public bool NonTerminalHint {
			get { return Marshal.ReadInt32 (handle, non_terminal_hint_offset) != 0; }
		}
		static readonly int non_terminal_hint_offset = (int)Marshal.OffsetOf<SoundIoInStream> ("non_terminal_hint");

		public int BytesPerFrame {
			get { return Marshal.ReadInt32 (handle, bytes_per_frame_offset); }
		}
		static readonly int bytes_per_frame_offset = (int)Marshal.OffsetOf<SoundIoInStream> ("bytes_per_frame");

		public int BytesPerSample {
			get { return Marshal.ReadInt32 (handle, bytes_per_sample_offset); }
		}
		static readonly int bytes_per_sample_offset = (int)Marshal.OffsetOf<SoundIoInStream> ("bytes_per_sample");

		public string LayoutErrorMessage {
			get {
				var code = (SoundIoError) Marshal.ReadInt32 (handle, layout_error_offset);
				return code == SoundIoError.SoundIoErrorNone ? null : Marshal.PtrToStringAnsi (Natives.soundio_strerror ((int) code));
			}
		}
		static readonly int layout_error_offset = (int)Marshal.OffsetOf<SoundIoInStream> ("layout_error");

		// functions

		public void Open ()
		{
			var ret = (SoundIoError) Natives.soundio_instream_open (handle);
			if (ret != SoundIoError.SoundIoErrorNone)
				throw new SoundIOException (ret);
		}

		public void Start ()
		{
			var ret = (SoundIoError)Natives.soundio_instream_start (handle);
			if (ret != SoundIoError.SoundIoErrorNone)
				throw new SoundIOException (ret);
		}

		public SoundIOChannelAreas BeginRead (ref int frameCount)
		{
			IntPtr ptrs = default (IntPtr);
			int nativeFrameCount = frameCount;
			unsafe {
				var frameCountPtr = &nativeFrameCount;
				var ptrptr = &ptrs;
				var ret = (SoundIoError) Natives.soundio_instream_begin_read (handle, (IntPtr)ptrptr, (IntPtr)frameCountPtr);
				frameCount = *frameCountPtr;
				if (ret != SoundIoError.SoundIoErrorNone)
					throw new SoundIOException (ret);
				return new SoundIOChannelAreas (ptrs, Layout.ChannelCount, frameCount);
			}
		}

		public void EndRead ()
		{
			var ret = (SoundIoError) Natives.soundio_instream_end_read (handle);
			if (ret != SoundIoError.SoundIoErrorNone)
				throw new SoundIOException (ret);
		}

		public void Pause (bool pause)
		{
			var ret = (SoundIoError) Natives.soundio_instream_pause (handle, pause);
			if (ret != SoundIoError.SoundIoErrorNone)
				throw new SoundIOException (ret);
		}

		public double GetLatency ()
		{
			unsafe {
				double* dptr = null;
				IntPtr p = new IntPtr (dptr);
				var ret = (SoundIoError) Natives.soundio_instream_get_latency (handle, p);
				if (ret != SoundIoError.SoundIoErrorNone)
					throw new SoundIOException (ret);
				dptr = (double*) p;
				return *dptr;
			}
		}
	}
}