using System;
using System.Runtime.InteropServices;

namespace Nerfed.Runtime.Audio;

/// <summary>
/// Contains raw audio data in a specified Format. <br/>
/// Submit this to a SourceVoice to play audio.
/// </summary>
public class AudioBuffer : AudioResource
{
	IntPtr BufferDataPtr;
	uint BufferDataLength;
	private bool OwnsBufferData;

	public Format Format { get; }

	/// <summary>
	/// Create a new AudioBuffer.
	/// </summary>
	/// <param name="ownsBufferData">If true, the buffer data will be destroyed when this AudioBuffer is destroyed.</param>
	public AudioBuffer(
		AudioDevice device,
		Format format,
		IntPtr bufferPtr,
		uint bufferLengthInBytes,
		bool ownsBufferData) : base(device)
	{
		Format = format;
		BufferDataPtr = bufferPtr;
		BufferDataLength = bufferLengthInBytes;
		OwnsBufferData = ownsBufferData;
	}

	/// <summary>
	/// Create another AudioBuffer from this audio buffer.
	/// It will not own the buffer data.
	/// </summary>
	/// <param name="offset">Offset in bytes from the top of the original buffer.</param>
	/// <param name="length">Length in bytes of the new buffer.</param>
	/// <returns></returns>
	public AudioBuffer Slice(int offset, uint length)
	{
		return new AudioBuffer(Device, Format, BufferDataPtr + offset, length, false);
	}

	/// <summary>
	/// Create an FAudioBuffer struct from this AudioBuffer.
	/// </summary>
	/// <param name="loop">Whether we should set the FAudioBuffer to loop.</param>
	public FAudio.FAudioBuffer ToFAudioBuffer(bool loop = false)
	{
		return new FAudio.FAudioBuffer
		{
			Flags = FAudio.FAUDIO_END_OF_STREAM,
			pContext = IntPtr.Zero,
			pAudioData = BufferDataPtr,
			AudioBytes = BufferDataLength,
			PlayBegin = 0,
			PlayLength = 0,
			LoopBegin = 0,
			LoopLength = 0,
			LoopCount = loop ? FAudio.FAUDIO_LOOP_INFINITE : 0
		};
	}

	protected override unsafe void Dispose(bool disposing)
	{
		if (!IsDisposed)
		{
			if (OwnsBufferData)
			{
				NativeMemory.Free((void*) BufferDataPtr);
			}
		}
		base.Dispose(disposing);
	}
}