// Fill out your copyright notice in the Description page of Project Settings.


#include "SPlayListTimeLine.h"

#include "SlateOptMacros.h"
#include "Singleton/MidiSequencer.h"

BEGIN_SLATE_FUNCTION_BUILD_OPTIMIZATION
void SPlayListTimeLine::Construct(const FArguments& InArgs)
{
	FrameRange = InArgs._FrameRange;
	/*
	ChildSlot
	[
		// Populate the widget
	];
	*/
	MainStepColor = FLinearColor(0.2f, 0.2f, 0.2f, 1.f);
	SubStepColor = FLinearColor(0.1f, 0.1f, 0.1f, 1.f);
}

int32 SPlayListTimeLine::OnPaint(const FPaintArgs& Args, const FGeometry& AllottedGeometry, const FSlateRect& MyCullingRect, FSlateWindowElementList& OutDrawElements, int32 LayerId, const FWidgetStyle& InWidgetStyle, bool bParentEnabled) const
{
	const AudioFrame Step = FMidiSequencer::Get().GetBar().Frames();
	const AudioFrame SubStep = FMidiSequencer::Get().GetBeat().Frames();
	
	const TRange<AudioFrame> Range = FrameRange.Get();
	
	const auto& Size = AllottedGeometry.Size;
	const float FrameToPixelScaler = Size.X / Range.Size<float>();
	const int32 StepRate = FMath::FloorToInt(Step / SubStep);
	if (StepRate < 0)
		return LayerId;
	
	const int32 MakerCount = FMath::CeilToInt(Range.Size<float>() / Step) + 1;
	const int32 SubMakerLineCount = StepRate * MakerCount + 1;
	
	const float Offset = FMath::Fmod(Range.GetLowerBoundValue(), Step);

	// Push clip rect
	FSlateClippingZone ClippingZone(AllottedGeometry);
	OutDrawElements.PushClip(ClippingZone);
	
	++LayerId;
	// const float SubLinePadding = AllottedGeometry.Size.Y * 0.4f;
	const FPaintGeometry LinePaintGeometry = AllottedGeometry.ToPaintGeometry();
	for (int i = 0; i < SubMakerLineCount; ++i)
	{
		const bool bIsSubMaker = i % StepRate != 0;

		const float X = (i * SubStep - Offset) * FrameToPixelScaler;
		// const float YPadding = bIsSubMaker ? SubLinePadding : 0;
		TArray<FVector2D> Points;
		Points.Add(FVector2D(X, 0));
		Points.Add(FVector2D(X, AllottedGeometry.Size.Y));
		
		FSlateDrawElement::MakeLines(OutDrawElements, LayerId, LinePaintGeometry, Points, ESlateDrawEffect::None, bIsSubMaker ? SubStepColor : MainStepColor, true, 1.f);
	}
	OutDrawElements.PopClip();
	
	return LayerId;
}

FReply SPlayListTimeLine::OnMouseButtonDown(const FGeometry& MyGeometry, const FPointerEvent& MouseEvent)
{
	if (MouseEvent.GetEffectingButton() == EKeys::LeftMouseButton)
	{
		SetTimePos(MyGeometry, MouseEvent);
		return FReply::Handled().CaptureMouse(AsShared());
	}
	return FReply::Unhandled();
}

FReply SPlayListTimeLine::OnMouseButtonUp(const FGeometry& MyGeometry, const FPointerEvent& MouseEvent)
{
	if (MouseEvent.GetEffectingButton() == EKeys::LeftMouseButton)
		return FReply::Handled().ReleaseMouseCapture();
	return FReply::Unhandled(); 
}

FReply SPlayListTimeLine::OnMouseMove(const FGeometry& MyGeometry, const FPointerEvent& MouseEvent)
{
	if (MouseEvent.IsMouseButtonDown(EKeys::LeftMouseButton))
	{
		SetTimePos(MyGeometry, MouseEvent);
	}
	return FReply::Handled();
}

void SPlayListTimeLine::SetTimePos(const FGeometry& MyGeometry, const FPointerEvent& MouseEvent)
{
	const auto& Size = MyGeometry.Size;
	const TRange<AudioFrame> Range = FrameRange.Get();
	const float FrameToPixelScaler = Size.X / Range.Size<float>();

	const float X = MyGeometry.AbsoluteToLocal(MouseEvent.GetScreenSpacePosition()).X;
	const bool NoSnap = MouseEvent.GetModifierKeys().IsAltDown();
	AudioFrame Frame = X / FrameToPixelScaler + Range.GetLowerBoundValue();
	if (!NoSnap)
		Frame = FMath::GridSnap(Frame.Pos, FMidiSequencer::Get().GetBeat().Frames());
	if (Frame.Pos < 0)
		Frame = 0;
	if (LastFrame == Frame)
		return;
	
	LastFrame = Frame;
	FMidiSequencer::Get().FramePos = Frame;
}

END_SLATE_FUNCTION_BUILD_OPTIMIZATION