// Copyright Epic Games, Inc. All Rights Reserved.

#include "AudioMixerSourceBuffer.h"
#include "AudioMixerSourceDecode.h"
#include "ContentStreaming.h"
#include "AudioDecompress.h"
#include "Misc/ScopeTryLock.h"
#include "DSP/FloatArrayMath.h"

namespace Audio
{
	int32 DirectProceduralRenderingCVar = 0;
	FAutoConsoleVariableRef CVarDirectProceduralRendering(
		TEXT("au.DirectProceduralRendering"),
		DirectProceduralRenderingCVar,
		TEXT("Render procedural sources (e.g. MetaSounds) on demand on the render thread, instead of using background tasks.\n")
		TEXT("It is only safe to change this setting when there are no sounds playing.\n")
		TEXT("0: Disabled, 1: Enabled"),
		ECVF_Default);

	bool FRawPCMDataBuffer::GetNextBuffer(TArrayView<float> OutSourceBufferPtr, const uint32 NumSampleToGet)
	{
		// TODO: support loop counts
		float* OutBufferPtr = OutSourceBufferPtr.GetData();
		int16* DataPtr = (int16*)Data;

		if (LoopCount == Audio::LOOP_FOREVER)
		{
			bool bIsFinishedOrLooped = false;
			for (uint32 Sample = 0; Sample < NumSampleToGet; ++Sample)
			{
				OutBufferPtr[Sample] = DataPtr[CurrentSample++] / 32768.0f;

				// Loop around if we're looping
				if (CurrentSample >= NumSamples)
				{
					CurrentSample = 0;
					bIsFinishedOrLooped = true;
				}
			}
			return bIsFinishedOrLooped;
		}
		else if (CurrentSample < NumSamples)
		{
			uint32 Sample = 0;
			while (Sample < NumSampleToGet && CurrentSample < NumSamples)
			{
				OutBufferPtr[Sample++] = (float)DataPtr[CurrentSample++] / 32768.0f;
			}

			// Zero out the rest of the buffer
			FMemory::Memzero(&OutBufferPtr[Sample], (NumSampleToGet - Sample) * sizeof(float));
		}
		else
		{
			FMemory::Memzero(OutBufferPtr, NumSampleToGet * sizeof(float));
		}

		// If the current sample is greater or equal to num samples we hit the end of the buffer
		return CurrentSample >= NumSamples;
	}

	TSharedPtr<FMixerSourceBuffer, ESPMode::ThreadSafe> FMixerSourceBuffer::Create(FMixerSourceBufferInitArgs& InArgs, TArray<FAudioParameter>&& InDefaultParams)
	{
		LLM_SCOPE(ELLMTag::AudioMixer);

		// Fail if the Wave has been flagged to contain an error
		if (InArgs.SoundWave && InArgs.SoundWave->HasError())
		{
			UE_LOG(LogAudioMixer, VeryVerbose, TEXT("FMixerSourceBuffer::Create failed as '%s' is flagged as containing errors"), *InArgs.SoundWave->GetName());
			return {};
		}

		TSharedPtr<FMixerSourceBuffer, ESPMode::ThreadSafe> NewSourceBuffer = MakeShareable(new FMixerSourceBuffer(InArgs, MoveTemp(InDefaultParams)));

		return NewSourceBuffer;
	}

	FMixerSourceBuffer::FMixerSourceBuffer(FMixerSourceBufferInitArgs& InArgs, TArray<FAudioParameter>&& InDefaultParams)
		: NumBuffersQeueued(0)
		, CurrentBuffer(0)
		, SoundWave(InArgs.SoundWave)
		, AsyncRealtimeAudioTask(nullptr)
		, DecompressionState(nullptr)
		, LoopingMode(InArgs.LoopingMode)
		, NumChannels(InArgs.Buffer->NumChannels)
		, BufferType(InArgs.Buffer->GetType())
		, NumPrecacheFrames(InArgs.SoundWave->NumPrecacheFrames)
		, AuioDeviceID(InArgs.AudioDeviceID)
		, InstanceID(InArgs.InstanceID)
		, WaveName(InArgs.SoundWave->GetFName())
#if ENABLE_AUDIO_DEBUG
		, SampleRate(InArgs.SampleRate)
#endif // ENABLE_AUDIO_DEBUG
		, bInitialized(false)
		, bBufferFinished(false)
		, bPlayedCachedBuffer(false)
		, bIsSeeking(InArgs.bIsSeeking)
		, bLoopCallback(false)
		, bProcedural(InArgs.SoundWave->bProcedural)
		, bIsBus(InArgs.SoundWave->bIsSourceBus)
		, bForceSyncDecode(InArgs.bForceSyncDecode)
		, bHasError(false)
		, bDirectRendering(InArgs.SoundWave->bProcedural && DirectProceduralRenderingCVar)
	{
		// TODO: remove the need to do this here. 1) remove need for decoders to depend on USoundWave and 2) remove need for procedural sounds to use USoundWaveProcedural
		InArgs.SoundWave->AddPlayingSource(this);

		// Retrieve a sound generator if this is a procedural sound wave
		if (bProcedural)
		{
			FSoundGeneratorInitParams InitParams;
			InitParams.AudioDeviceID = InArgs.AudioDeviceID;
			InitParams.AudioComponentId = InArgs.AudioComponentID;
			InitParams.SampleRate = InArgs.SampleRate;
			InitParams.AudioMixerNumOutputFrames = InArgs.AudioMixerNumOutputFrames;
			InitParams.NumChannels = NumChannels;
			InitParams.NumFramesPerCallback = MONO_PCM_BUFFER_SAMPLES;
			InitParams.InstanceID = InArgs.InstanceID;
			InitParams.bIsPreviewSound = InArgs.bIsPreviewSound;
			InitParams.StartTime = InArgs.StartTime;

			SoundGenerator = InArgs.SoundWave->CreateSoundGenerator(InitParams, MoveTemp(InDefaultParams));

			// In the case of procedural audio generation, the mixer source buffer will never "loop" -- i.e. when it's done, it's done
			LoopingMode = LOOP_Never;
		}

		// Only allocate one buffer to render into when doing direct rendering
		const int32 NumBuffers = bDirectRendering ? 1 : Audio::MAX_BUFFERS_QUEUED;

		const uint32 TotalSamples = (bDirectRendering && SoundGenerator.IsValid()) ? SoundGenerator->GetDesiredNumSamplesToRenderPerCallback() : MONO_PCM_BUFFER_SAMPLES * NumChannels;
		for (int32 BufferIndex = 0; BufferIndex < NumBuffers; ++BufferIndex)
		{
			SourceVoiceBuffers.Add(MakeShared<FAlignedFloatBuffer, ESPMode::ThreadSafe>());

			// Prepare the memory to fit the max number of samples
			SourceVoiceBuffers[BufferIndex]->Reset(TotalSamples);
		}
	}

	FMixerSourceBuffer::~FMixerSourceBuffer()
	{
		// GC methods may get called from the game thread during the destructor
		// These methods will trylock and early exit if we have this lock
		FScopeLock Lock(&SoundWaveCritSec);

		// OnEndGenerate calls EnsureTaskFinishes,
		// which will make sure we have completed our async realtime task before deleting the decompression state
		OnEndGenerate();

		// Clean up decompression state after things have been finished using it
		DeleteDecoder();

		if (SoundWave)
		{
			SoundWave->RemovePlayingSource(this);
		}
	}

	void FMixerSourceBuffer::SetDecoder(ICompressedAudioInfo* InCompressedAudioInfo)
	{
		if (DecompressionState == nullptr)
		{
			DecompressionState = InCompressedAudioInfo;
		}
	}

	void FMixerSourceBuffer::SetPCMData(const FRawPCMDataBuffer& InPCMDataBuffer)
	{
		check(BufferType == EBufferType::PCM || BufferType == EBufferType::PCMPreview);
		RawPCMDataBuffer = InPCMDataBuffer;
	}

	void FMixerSourceBuffer::SetCachedRealtimeFirstBuffers(TArray<uint8>&& InPrecachedBuffers)
	{
		CachedRealtimeFirstBuffer = MoveTemp(InPrecachedBuffers);
	}

	bool FMixerSourceBuffer::Init()
	{
		// We have successfully initialized which means our SoundWave has been flagged as bIsActive
		// GC can run between PreInit and Init so when cleaning up FMixerSourceBuffer, we don't want to touch SoundWave unless bInitailized is true.
		// SoundWave->bIsSoundActive will prevent GC until it is released in audio render thread
		bInitialized = true;

		switch (BufferType)
		{
		case EBufferType::PCM:
		case EBufferType::PCMPreview:
			SubmitInitialPCMBuffers();
			break;

		case EBufferType::PCMRealTime:
		case EBufferType::Streaming:
			if (!bDirectRendering)
			{
				SubmitInitialRealtimeBuffers();
			}
			break;

		case EBufferType::Invalid:
			break;
		}

		return true;
	}

	void FMixerSourceBuffer::OnBufferEnd()
	{
		if (bDirectRendering)
		{
			return;
		}

		FScopeTryLock Lock(&SoundWaveCritSec);

		// If the buffer is flagged as complete and there's nothing queued remaining.
		const bool bBufferCompleted = (NumBuffersQeueued == 0 && bBufferFinished);

		// If we're procedural we must have a procedural SoundWave pointer to continue.
		const bool bProceduralStateBad = (bProcedural && !SoundWave);

		// If we're non-procedural and we don't have a decoder, bail. This can happen when the wave is GC'd.
		// The Decoder and SoundWave is deleted on the GameThread via FMixerSourceBuffer::OnBeginDestroy
		// Although this is bad state it's not an error, so just bail here.
		const bool bDecompressionStateBad = (!bProcedural && DecompressionState == nullptr);

		if (!Lock.IsLocked() || bBufferCompleted || bProceduralStateBad || bDecompressionStateBad || bHasError)
		{
			return;
		}

		ProcessRealTimeSource();
	}

	int32 FMixerSourceBuffer::GetNumBuffersQueued() const
	{
		FScopeTryLock Lock(&SoundWaveCritSec);
		if (Lock.IsLocked())
		{
			return NumBuffersQeueued;
		}

		return 0;
	}

	TSharedPtr<FAlignedFloatBuffer, ESPMode::ThreadSafe> FMixerSourceBuffer::GetNextBuffer()
	{
		FScopeTryLock Lock(&SoundWaveCritSec);
		if (!Lock.IsLocked())
		{
			return nullptr;
		}

		if (bDirectRendering)
		{
			// Do rendering immediately.
			FProceduralAudioTaskData NewTaskData;

			// Make sure we actually have something to render
			check(SoundGenerator.IsValid() || (SoundWave && SoundWave->bProcedural));

			const int32 MaxSamples = SoundGenerator.IsValid() ? SoundGenerator->GetDesiredNumSamplesToRenderPerCallback() : MONO_PCM_BUFFER_SAMPLES * NumChannels;
			check(CurrentBuffer == 0);
			SourceVoiceBuffers[0]->SetNumUninitialized(MaxSamples, EAllowShrinking::No);

			NewTaskData.SourceBuffer = this;
			NewTaskData.SoundGenerator = SoundGenerator;
			NewTaskData.AudioData = SourceVoiceBuffers[0]->GetData();
			NewTaskData.NumSamples = MaxSamples;

			FProceduralAudioTaskResults Results;
			DoProceduralRendering(NewTaskData, Results);
			FinishProceduralRendering(Results);
			bBufferFinished = Results.bIsFinished;

			return SourceVoiceBuffers[0];
		}

		TSharedPtr<FAlignedFloatBuffer, ESPMode::ThreadSafe> NewBufferPtr;
		BufferQueue.Dequeue(NewBufferPtr);
		--NumBuffersQeueued;
		return NewBufferPtr;
	}

	void FMixerSourceBuffer::DoProceduralRendering(const FProceduralAudioTaskData& ProceduralTaskData, FProceduralAudioTaskResults& ProceduralResult)
	{
#if ENABLE_AUDIO_DEBUG
		FScopeDecodeTimer Timer(&ProceduralResult.CPUDuration);
#endif // if ENABLE_AUDIO_DEBUG
		QUICK_SCOPE_CYCLE_COUNTER(STAT_FAsyncDecodeWorker_Procedural);
		if (ProceduralTaskData.SoundGenerator.IsValid())
		{
			// Generators are responsible to zero memory in case they can't generate the requested amount of samples
			ProceduralResult.NumSamplesWritten = ProceduralTaskData.SoundGenerator->GetNextBuffer(ProceduralTaskData.AudioData, ProceduralTaskData.NumSamples);
			ProceduralResult.bIsFinished = ProceduralTaskData.SoundGenerator->IsFinished();
			ProceduralResult.RelativeRenderCost = ProceduralTaskData.SoundGenerator->GetRelativeRenderCost();
		}
		else
		{
			// Make sure we've been flagged as active
			if (!SoundWave || !SoundWave->IsGeneratingAudio())
			{
				// Act as if we generated audio, but return silence.
				FMemory::Memzero(ProceduralTaskData.AudioData, ProceduralTaskData.NumSamples * sizeof(float));
				ProceduralResult.NumSamplesWritten = ProceduralTaskData.NumSamples;
				return;
			}

			// If we're not a float format, we need to convert the format to float
			const EAudioMixerStreamDataFormat::Type FormatType = SoundWave->GetGeneratedPCMDataFormat();
			if (FormatType != EAudioMixerStreamDataFormat::Float)
			{
				check(FormatType == EAudioMixerStreamDataFormat::Int16);

				int32 ByteSize = NumChannels * ProceduralTaskData.NumSamples * sizeof(int16);

				TArray<uint8> DecodeBuffer;
				DecodeBuffer.AddUninitialized(ByteSize);

				const int32 NumBytesWritten = SoundWave->GeneratePCMData(DecodeBuffer.GetData(), ProceduralTaskData.NumSamples);

				check(NumBytesWritten <= ByteSize);

				ProceduralResult.NumSamplesWritten = NumBytesWritten / sizeof(int16);
				Audio::ArrayPcm16ToFloat(MakeArrayView((int16*)DecodeBuffer.GetData(), ProceduralResult.NumSamplesWritten)
					, MakeArrayView(ProceduralTaskData.AudioData, ProceduralResult.NumSamplesWritten));
			}
			else
			{
				const int32 NumBytesWritten = SoundWave->GeneratePCMData((uint8*)ProceduralTaskData.AudioData, ProceduralTaskData.NumSamples);
				ProceduralResult.NumSamplesWritten = NumBytesWritten / sizeof(float);
			}
		}
	}

	void FMixerSourceBuffer::FinishProceduralRendering(const FProceduralAudioTaskResults& TaskResult)
	{
		// When doing direct rendering, should only ever use buffer 0
		check(!bDirectRendering || CurrentBuffer == 0);

		SourceVoiceBuffers[CurrentBuffer]->SetNum(TaskResult.NumSamplesWritten, EAllowShrinking::No);

#if ENABLE_AUDIO_DEBUG
		double AudioDuration = static_cast<double>(TaskResult.NumSamplesWritten) / static_cast<double>(FMath::Max(1, NumChannels * SampleRate));
		UpdateCPUCoreUtilization(TaskResult.CPUDuration, AudioDuration);
#endif // ENABLE_AUDIO_DEBUG

		// Set the render cost encountered during the last render
		SetRelativeRenderCost(TaskResult.RelativeRenderCost);
	}

	void FMixerSourceBuffer::SubmitInitialPCMBuffers()
	{
		CurrentBuffer = 0;

		RawPCMDataBuffer.NumSamples = RawPCMDataBuffer.DataSize / sizeof(int16);
		RawPCMDataBuffer.CurrentSample = 0;

		// Only submit data if we've successfully loaded it
		if (!RawPCMDataBuffer.Data || !RawPCMDataBuffer.DataSize)
		{
			return;
		}

		RawPCMDataBuffer.LoopCount = (LoopingMode != LOOP_Never) ? Audio::LOOP_FOREVER : 0;

		// Submit the first two format-converted chunks to the source voice
		const uint32 NumSamplesPerBuffer = MONO_PCM_BUFFER_SAMPLES * NumChannels;
		int16* RawPCMBufferDataPtr = (int16*)RawPCMDataBuffer.Data;

		// Prepare the buffer for the PCM submission
		SourceVoiceBuffers[0]->Reset(NumSamplesPerBuffer);
		SourceVoiceBuffers[0]->AddZeroed(NumSamplesPerBuffer);

		RawPCMDataBuffer.GetNextBuffer(*SourceVoiceBuffers[0], NumSamplesPerBuffer);

		SubmitBuffer(SourceVoiceBuffers[0]);

		CurrentBuffer = 1;
	}

	void FMixerSourceBuffer::SubmitInitialRealtimeBuffers()
	{
		static_assert(PLATFORM_NUM_AUDIODECOMPRESSION_PRECACHE_BUFFERS <= 2 && PLATFORM_NUM_AUDIODECOMPRESSION_PRECACHE_BUFFERS >= 0, "Unsupported number of precache buffers.");
		check(!bDirectRendering);

		CurrentBuffer = 0;

		bPlayedCachedBuffer = false;
		if (!bIsSeeking && CachedRealtimeFirstBuffer.Num() > 0)
		{
			bPlayedCachedBuffer = true;

			const uint32 NumSamples = NumPrecacheFrames * NumChannels;
			const uint32 BufferSize = NumSamples * sizeof(int16);

			// Format convert the first cached buffers
#if (PLATFORM_NUM_AUDIODECOMPRESSION_PRECACHE_BUFFERS == 2)
			{
				// Prepare the precache buffer memory
				for (int32 i = 0; i < 2; ++i)
				{
					SourceVoiceBuffers[i]->Reset();
					SourceVoiceBuffers[i]->AddZeroed(NumSamples);
				}

				int16* CachedBufferPtr0 = (int16*)CachedRealtimeFirstBuffer.GetData();
				int16* CachedBufferPtr1 = (int16*)(CachedRealtimeFirstBuffer.GetData() + BufferSize);
				float* AudioData0 = SourceVoiceBuffers[0]->GetData();
				float* AudioData1 = SourceVoiceBuffers[1]->GetData();

				Audio::ArrayPcm16ToFloat(MakeArrayView(CachedBufferPtr0, NumSamples), MakeArrayView(AudioData0, NumSamples));
				Audio::ArrayPcm16ToFloat(MakeArrayView(CachedBufferPtr1, NumSamples), MakeArrayView(AudioData1, NumSamples));

				// Submit the already decoded and cached audio buffers
				SubmitBuffer(SourceVoiceBuffers[0]);
				SubmitBuffer(SourceVoiceBuffers[1]);

				CurrentBuffer = 2;
			}
#elif (PLATFORM_NUM_AUDIODECOMPRESSION_PRECACHE_BUFFERS == 1)
			{
				SourceVoiceBuffers[0]->AudioData.Reset();
				SourceVoiceBuffers[0]->AudioData.AddZeroed(NumSamples);

				int16* CachedBufferPtr0 = (int16*)CachedRealtimeFirstBuffer.GetData();
				float* AudioData0 = SourceVoiceBuffers[0]->AudioData.GetData();
				Audio::ArrayPcm16ToFloat(MakeArrayView(CachedBufferPtr0, NumSamples), MakeArrayView(AudioData0, NumSamples));

				// Submit the already decoded and cached audio buffers
				SubmitBuffer(SourceVoiceBuffers[0]);

				CurrentBuffer = 1;
			}
#endif
		}
		else if (!bIsBus)
		{
			ProcessRealTimeSource();
		}
	}

	bool FMixerSourceBuffer::ReadMoreRealtimeData(ICompressedAudioInfo* InDecoder, const int32 BufferIndex, EBufferReadMode BufferReadMode)
	{
		check(!bDirectRendering);
		const int32 MaxSamples = MONO_PCM_BUFFER_SAMPLES * NumChannels;

		SourceVoiceBuffers[BufferIndex]->Reset();
		SourceVoiceBuffers[BufferIndex]->AddUninitialized(MaxSamples);

		if (bProcedural)
		{
			FScopeTryLock Lock(&SoundWaveCritSec);

			if (Lock.IsLocked() && SoundWave)
			{
				FProceduralAudioTaskData NewTaskData;

				// Make sure we actually have something to render
				check(SoundGenerator.IsValid() || (SoundWave && SoundWave->bProcedural));

				NewTaskData.SourceBuffer = this;
				NewTaskData.SoundGenerator = SoundGenerator;
				NewTaskData.AudioData = SourceVoiceBuffers[BufferIndex]->GetData();
				NewTaskData.NumSamples = MaxSamples;
				AsyncTaskStartTimeInCycles = FPlatformTime::Cycles64();
				check(!AsyncRealtimeAudioTask);
				AsyncRealtimeAudioTask = CreateAudioTask(AuioDeviceID, NewTaskData);
			}

			return false;
		}
		else if (BufferType != EBufferType::PCMRealTime && BufferType != EBufferType::Streaming)
		{
			check(RawPCMDataBuffer.Data != nullptr);

			// Read the next raw PCM buffer into the source buffer index. This converts raw PCM to float.
			return RawPCMDataBuffer.GetNextBuffer(*SourceVoiceBuffers[BufferIndex], MaxSamples);
		}

		// Handle the case that the decoder has an error and can't continue.
		if (InDecoder && InDecoder->HasError())
		{
			FMemory::Memzero(SourceVoiceBuffers[BufferIndex]->GetData(), MaxSamples * sizeof(float));

			FScopeTryLock Lock(&SoundWaveCritSec);
			if (Lock.IsLocked() && SoundWave)
			{
				SoundWave->SetError(TEXT("ICompressedAudioInfo::HasError() flagged on the Decoder"));
			}

			bHasError = true;
			bBufferFinished = true;
			return false;
		}

		check(InDecoder != nullptr);

		FDecodeAudioTaskData NewTaskData;
		NewTaskData.AudioData = SourceVoiceBuffers[BufferIndex]->GetData();
		NewTaskData.DecompressionState = InDecoder;
		NewTaskData.BufferType = BufferType;
		NewTaskData.NumChannels = NumChannels;
		NewTaskData.bLoopingMode = LoopingMode != LOOP_Never;
		NewTaskData.bSkipFirstBuffer = (BufferReadMode == EBufferReadMode::AsynchronousSkipFirstFrame);
		NewTaskData.NumFramesToDecode = MONO_PCM_BUFFER_SAMPLES;
		NewTaskData.NumPrecacheFrames = NumPrecacheFrames;
		NewTaskData.bForceSyncDecode = bForceSyncDecode;

		AsyncTaskStartTimeInCycles = FPlatformTime::Cycles64();
		FScopeLock Lock(&DecodeTaskCritSec);
		check(!AsyncRealtimeAudioTask);
		AsyncRealtimeAudioTask = CreateAudioTask(AuioDeviceID, NewTaskData);

		return false;
	}

	void FMixerSourceBuffer::SubmitRealTimeSourceData(const bool bInIsFinishedOrLooped)
	{
		// Have we reached the end of the sound
		if (bInIsFinishedOrLooped)
		{
			switch (LoopingMode)
			{
			case LOOP_Never:
				// Play out any queued buffers - once there are no buffers left, the state check at the beginning of IsFinished will fire
				bBufferFinished = true;
				break;

			case LOOP_WithNotification:
				// If we have just looped, and we are looping, send notification
				// This will trigger a WaveInstance->NotifyFinished() in the FXAudio2SoundSournce::IsFinished() function on main thread.
				bLoopCallback = true;
				break;

			case LOOP_Forever:
				// Let the sound loop indefinitely
				break;
			}
		}

		if (SourceVoiceBuffers[CurrentBuffer]->Num() > 0)
		{
			SubmitBuffer(SourceVoiceBuffers[CurrentBuffer]);
		}
	}

	void FMixerSourceBuffer::ProcessRealTimeSource()
	{
		FScopeLock Lock(&DecodeTaskCritSec);

		// Finish current decoding task
		if (AsyncRealtimeAudioTask)
		{
			AsyncRealtimeAudioTask->EnsureCompletion();

			bool bIsFinishedOrLooped = false;

			switch (AsyncRealtimeAudioTask->GetType())
			{
			case EAudioTaskType::Decode:
			{
				FDecodeAudioTaskResults TaskResult;
				AsyncRealtimeAudioTask->GetResult(TaskResult);
				bIsFinishedOrLooped = TaskResult.bIsFinishedOrLooped;

				SourceVoiceBuffers[CurrentBuffer]->SetNum(TaskResult.NumSamplesWritten, EAllowShrinking::No);
#if ENABLE_AUDIO_DEBUG
				double AudioDuration = static_cast<double>(TaskResult.NumSamplesWritten) / static_cast<double>(FMath::Max(1, NumChannels * SampleRate));
				UpdateCPUCoreUtilization(TaskResult.CPUDuration, AudioDuration);
#endif // ENABLE_AUDIO_DEBUG
			}
			break;

			case EAudioTaskType::Procedural:
			{
				FProceduralAudioTaskResults TaskResult;
				AsyncRealtimeAudioTask->GetResult(TaskResult);
				FinishProceduralRendering(TaskResult);
				bIsFinishedOrLooped = TaskResult.bIsFinished;
			}
			break;
			}

			delete AsyncRealtimeAudioTask;
			AsyncRealtimeAudioTask = nullptr;
			AsyncTaskStartTimeInCycles = 0;

			SubmitRealTimeSourceData(bIsFinishedOrLooped);
		}

		if (FAudioDeviceManager* ADM = FAudioDeviceManager::Get())
		{
			if (FAudioDevice* AudioDevice = ADM->GetAudioDeviceRaw(AuioDeviceID))
			{
				UAudioBusSubsystem* AudioBusSubsystem = AudioDevice->GetSubsystem<UAudioBusSubsystem>();
				check(AudioBusSubsystem);
				AudioBusSubsystem->ConnectPatches(InstanceID);
			}
		}

		// Start a new decoding task
		if (!AsyncRealtimeAudioTask && !bDirectRendering)
		{
			// Update the buffer index
			if (++CurrentBuffer > 2)
			{
				CurrentBuffer = 0;
			}

			EBufferReadMode DataReadMode;
			if (bPlayedCachedBuffer)
			{
				bPlayedCachedBuffer = false;
				DataReadMode = EBufferReadMode::AsynchronousSkipFirstFrame;
			}
			else
			{
				DataReadMode = EBufferReadMode::Asynchronous;
			}

			const bool bIsFinishedOrLooped = ReadMoreRealtimeData(DecompressionState, CurrentBuffer, DataReadMode);

			// If this was a synchronous read, then immediately write it
			if (AsyncRealtimeAudioTask == nullptr && !bHasError)
			{
				SubmitRealTimeSourceData(bIsFinishedOrLooped);
			}
		}

		if (bDirectRendering)
		{
			check(CurrentBuffer == 0);
			SubmitBuffer(SourceVoiceBuffers[CurrentBuffer]);
		}
	}

	void FMixerSourceBuffer::SubmitBuffer(TSharedPtr<FAlignedFloatBuffer, ESPMode::ThreadSafe> InSourceVoiceBuffer)
	{
		NumBuffersQeueued++;
		BufferQueue.Enqueue(InSourceVoiceBuffer);
	}

	bool FMixerSourceBuffer::IsEndOfAudio() const
	{
		return bDirectRendering ? bBufferFinished : GetNumBuffersQueued() == 0;
	}

	void FMixerSourceBuffer::DeleteDecoder()
	{
		// Clean up decompression state after things have been finished using it
		if (DecompressionState)
		{
			delete DecompressionState;
			DecompressionState = nullptr;
		}
	}

	bool FMixerSourceBuffer::OnBeginDestroy(USoundWave* /*Wave*/)
	{
		FScopeTryLock Lock(&SoundWaveCritSec);

		// if we don't have the lock, it means we are in ~FMixerSourceBuffer() on another thread
		if (Lock.IsLocked() && SoundWave)
		{
			EnsureAsyncTaskFinishes();
			DeleteDecoder();
			ClearWave();
			return true;
		}

		return false;
	}

	bool FMixerSourceBuffer::OnIsReadyForFinishDestroy(USoundWave* /*Wave*/) const
	{
		return false;
	}

	void FMixerSourceBuffer::OnFinishDestroy(USoundWave* /*Wave*/)
	{
		EnsureAsyncTaskFinishes();
		FScopeTryLock Lock(&SoundWaveCritSec);

		// if we don't have the lock, it means we are in ~FMixerSourceBuffer() on another thread
		if (Lock.IsLocked() && SoundWave)
		{
			DeleteDecoder();
			ClearWave();
		}
	}

	bool FMixerSourceBuffer::IsAsyncTaskInProgress() const
	{
		FScopeLock Lock(&DecodeTaskCritSec);
		return AsyncRealtimeAudioTask != nullptr;
	}

	bool FMixerSourceBuffer::IsAsyncTaskDone() const
	{
		FScopeLock Lock(&DecodeTaskCritSec);
		if (AsyncRealtimeAudioTask)
		{
			return AsyncRealtimeAudioTask->IsDone();
		}
		return true;
	}

	float FMixerSourceBuffer::GetRelativeRenderCost() const
	{
		return RelativeRenderCost.load(std::memory_order_relaxed);
	}

	void FMixerSourceBuffer::SetRelativeRenderCost(float InRelativeRenderCost)
	{
		RelativeRenderCost.store(InRelativeRenderCost, std::memory_order_relaxed);
	}

#if ENABLE_AUDIO_DEBUG
	double FMixerSourceBuffer::GetCPUCoreUtilization() const
	{
		return CPUCoreUtilization.load(std::memory_order_relaxed);
	}

	void FMixerSourceBuffer::UpdateCPUCoreUtilization(double InCPUTime, double InAudioTime)
	{
		constexpr double AnalysisTime = 1.0;

		if (InAudioTime > 0.0)
		{
			double NewUtilization = InCPUTime / InAudioTime;

			// Determine smoothing coefficients based upon duration of audio being rendered.
			const double DigitalCutoff = 1.0 / FMath::Max(1., AnalysisTime / InAudioTime);
			const double SmoothingBeta = FMath::Clamp(FMath::Exp(-UE_PI * DigitalCutoff), 0.0, 1.0 - UE_DOUBLE_SMALL_NUMBER);

			double PriorUtilization = CPUCoreUtilization.load(std::memory_order_relaxed);

			// Smooth value if utilization has been initialized.
			if (PriorUtilization > 0.0)
			{
				NewUtilization = (1.0 - SmoothingBeta) * NewUtilization + SmoothingBeta * PriorUtilization;
			}
			CPUCoreUtilization.store(NewUtilization, std::memory_order_relaxed);
		}
	}
#endif // ENABLE_AUDIO_DEBUG

	void FMixerSourceBuffer::GetDiagnosticState(FDiagnosticState& OutState)
	{
		// Query without a lock!
		OutState.bInFlight = AsyncRealtimeAudioTask != nullptr;
		OutState.WaveName = WaveName;
		OutState.bProcedural = bProcedural;
		OutState.RunTimeInSecs = OutState.bInFlight ?
			FPlatformTime::ToSeconds(FPlatformTime::Cycles64() - this->AsyncTaskStartTimeInCycles) :
			0.f;
	}

	void FMixerSourceBuffer::EnsureAsyncTaskFinishes()
	{
		FScopeLock Lock(&DecodeTaskCritSec);
		if (AsyncRealtimeAudioTask)
		{
			AsyncRealtimeAudioTask->CancelTask();

			delete AsyncRealtimeAudioTask;
			AsyncRealtimeAudioTask = nullptr;
		}
	}

	void FMixerSourceBuffer::OnBeginGenerate()
	{
		FScopeTryLock Lock(&SoundWaveCritSec);
		if (!Lock.IsLocked())
		{
			return;
		}

		if (SoundGenerator.IsValid())
		{
			SoundGenerator->OnBeginGenerate();
		}
		else
		{
			if (SoundWave && bProcedural)
			{
				check(SoundWave && SoundWave->bProcedural);
				SoundWave->OnBeginGenerate();
			}
		}
	}

	void FMixerSourceBuffer::OnEndGenerate()
	{
		// Make sure the async task finishes!
		EnsureAsyncTaskFinishes();

		FScopeTryLock Lock(&SoundWaveCritSec);
		if (!Lock.IsLocked())
		{
			return;
		}

		if (SoundGenerator.IsValid())
		{
			SoundGenerator->OnEndGenerate();
			if (SoundWave)
			{
				SoundWave->OnEndGenerate(SoundGenerator);
			}

			if (FAudioDeviceManager* ADM = FAudioDeviceManager::Get())
			{
				if (FAudioDevice* AudioDevice = ADM->GetAudioDeviceRaw(AuioDeviceID))
				{
					UAudioBusSubsystem* AudioBusSubsystem = AudioDevice->GetSubsystem<UAudioBusSubsystem>();
					check(AudioBusSubsystem);
					AudioBusSubsystem->RemoveSound(InstanceID);
				}
			}
		}
		else
		{
			// Only need to call OnEndGenerate and access SoundWave here if we successfully initialized
			if (SoundWave && bInitialized && bProcedural)
			{
				check(SoundWave && SoundWave->bProcedural);
				SoundWave->OnEndGenerate();
			}
		}
	}

}