#include "MidiSequencer.h"

#include "PortAudioAPI.h"
#include "PluginHostList.h"
#include "PluginHost/VST2PluginHost.h"

FMidiPattern* FMidiSequencer::NewMidiPattern()
{
	FMidiPattern* Pattern = new FMidiPattern();
	RegisterPattern(Pattern);
	return Pattern;
}

FSamplePattern* FMidiSequencer::NewSamplePattern(FSampler* InSampler)
{
	FSamplePattern* Pattern = new FSamplePattern(InSampler);
	RegisterPattern(Pattern);
	return Pattern;
}

void FMidiSequencer::DeletePattern(FPattern* Pattern)
{
	Patterns.Remove(Pattern);
	PatternTypeMap.FindChecked(Pattern->Type).Remove(Pattern);
	OnDeletePattern.Broadcast(Pattern);
	delete Pattern;
}

FPattern* FMidiSequencer::FindPattern(uint32 ID)
{
	for (FPattern* P : Patterns)
		if (P->ID == ID)
			return P;
	return nullptr;
}

void FMidiSequencer::Process(float SampleRate, uint32 FrameNum)
{
	if (!Playing.load())
		return;
	
	// 将Sample转换为MidiTick
	const float SamplePerBeat = SampleRate * 60.f / BPM;
	const double TickDelta = FrameNum / SamplePerBeat * TicksPerQuarter;

	for (const auto Pattern : Patterns)
	{
		Pattern->ProcessInstances(FramePos, FrameNum);
	}

	FramePos.store(FramePos.load().Pos + FrameNum);

	UpdateTime();
}

void FMidiSequencer::UpdateTime()
{
	VstTimeInfo& Info = VST2::VSTTimeInfo;
	Info.samplePos = FramePos.load();
	Info.sampleRate = FPortAudioAPI::Get().SampleRate;
	Info.nanoSeconds = FDateTime::Now().GetTicks() * ETimespan::NanosecondsPerTick;
	Info.ppqPos = FramePos.load().Ticks() / (double)TicksPerQuarter;
	Info.tempo = BPM;
	Info.barStartPos = 0;
	Info.cycleStartPos = 0;
	Info.cycleEndPos = 0;
	Info.timeSigNumerator = 4;
	Info.timeSigDenominator = 4;
	Info.smpteOffset = 0;
	Info.smpteFrameRate = 0;
	Info.samplesToNextClock = 0;
	Info.flags = kVstNanosValid | kVstPpqPosValid | kVstTempoValid;
	Info.flags |= kVstTransportPlaying;
}

void FMidiSequencer::ForeachPatternInstance(TFunctionRef<bool(FPatternInstance*)> Func)
{
	for (const FPattern* Pattern : Patterns)
	{
		const TArray<FPatternInstance*>& PatternInstances = Pattern->GetInstances();
		for (FPatternInstance* Instance : PatternInstances)
		{
			if (!Func(Instance))
				return;
		}
	}
}

float FMidiSequencer::FramesPerTick()
{
	const FPortAudioAPI& PortAudioAPI = FPortAudioAPI::Get();
	const FMidiSequencer& MidiSequencer = Get();
	return (PortAudioAPI.SampleRate * 60.0f) / (MidiSequencer.TicksPerQuarter * MidiSequencer.BPM);
}

void FMidiSequencer::SetPlaying(bool bPlaying)
{
	Playing = bPlaying;
	if (Playing == false)
	{
		FPluginHostList::Get().StopAllMidiOn();
	}
}

void FMidiSequencer::RegisterPattern(FPattern* InPattern)
{
	InPattern->ID = ++IDCounter;
	Patterns.Add(InPattern);
	PatternTypeMap.FindOrAdd(InPattern->Type).Add(InPattern);
	OnNewPattern.Broadcast(InPattern);
}