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


#include "SPlayList.h"

#include "SlateOptMacros.h"
#include "SPlayListTimeLine.h"
#include "PlayListPanel/SPlayListPanel.h"
#include "SScrollBox.h"

BEGIN_SLATE_FUNCTION_BUILD_OPTIMIZATION

void SPlayList::Construct(const FArguments& InArgs)
{
	FrameRange = TRange<AudioFrame>(0, FMidiSequencer::Get().GetBar().Frames() * 16.0);
	TargetFrameRange = FrameRange;
	
	ChildSlot
	[
		SNew(SVerticalBox)
		+SVerticalBox::Slot()
		.AutoHeight()
		.Padding(0, 0, 12, 0)
		[
			SAssignNew(TimeLine, SPlayListTimeLine)
			.FrameRange(this, &SPlayList::GetFrameRange)
		]
		+SVerticalBox::Slot()
		.FillHeight(1.f)
		[
			SAssignNew(ScrollBox, SScrollBox)
			.AnimateWheelScrolling(true)
			+SScrollBox::Slot()
			[
				SAssignNew(PlayListPanel, SPlayListPanel)
				.TrackHeight(64)
				.FrameRange(this, &SPlayList::GetFrameRange)
			]
		]
	];
}

void SPlayList::Tick(const FGeometry& AllottedGeometry, const double InCurrentTime, const float InDeltaTime)
{
	SCompoundWidget::Tick(AllottedGeometry, InCurrentTime, InDeltaTime);
	FrameRange.SetLowerBoundValue(FMath::FInterpTo<double>(FrameRange.GetLowerBoundValue(), TargetFrameRange.GetLowerBoundValue(), InDeltaTime, 20.f));
	FrameRange.SetUpperBoundValue(FMath::FInterpTo<double>(FrameRange.GetUpperBoundValue(), TargetFrameRange.GetUpperBoundValue(), InDeltaTime, 20.f));
}

FReply SPlayList::OnKeyDown(const FGeometry& MyGeometry, const FKeyEvent& InKeyEvent)
{
	if (!InKeyEvent.IsRepeat() && InKeyEvent.GetKey() == EKeys::SpaceBar)
		FMidiSequencer::Get().TogglePlay();
	if (!InKeyEvent.IsRepeat() && InKeyEvent.GetKey() == EKeys::LeftControl)
	{
		Zooming = true;
		ScrollBox->SetConsumeMouseWheel(EConsumeMouseWheel::Never);
	}
	if (!InKeyEvent.IsRepeat() && InKeyEvent.GetKey() == EKeys::LeftShift)
	{
		HorizonScrolling = true;
		ScrollBox->SetConsumeMouseWheel(EConsumeMouseWheel::Never);
	}
	return FReply::Handled();
}

FReply SPlayList::OnKeyUp(const FGeometry& MyGeometry, const FKeyEvent& InKeyEvent)
{
	if (InKeyEvent.GetKey() == EKeys::LeftControl)
		Zooming = false;
	if (InKeyEvent.GetKey() == EKeys::LeftShift)
		HorizonScrolling = false;
	if (!Zooming && !HorizonScrolling)
		ScrollBox->SetConsumeMouseWheel(EConsumeMouseWheel::Always);
	return FReply::Handled();
}

FReply SPlayList::OnMouseWheel(const FGeometry& MyGeometry, const FPointerEvent& InMouseEvent)
{
	if (Zooming)
	{
		const AudioFrame MinRange = FMidiSequencer::Get().GetBeat() * 4;

		const TRange<AudioFrame>& CurrentRange = TargetFrameRange;
		const AudioFrame WheelDelta = InMouseEvent.GetWheelDelta() * GetScalerLevel() * 2; // 乘以2是因为MousePosPercent

		if (WheelDelta.Pos > 0 && CurrentRange.Size<AudioFrame>() <= MinRange)
			return FReply::Handled();

		const FGeometry& PlayListPanelGeometry = PlayListPanel->GetTickSpaceGeometry();
		const FVector2f& PanelLocalMouse = PlayListPanelGeometry.AbsoluteToLocal(InMouseEvent.GetScreenSpacePosition());
		const double MousePosPercent = PanelLocalMouse.X / PlayListPanelGeometry.Size.X;
		
		AudioFrame Low = FMath::Max(0.f, CurrentRange.GetLowerBoundValue() + WheelDelta * MousePosPercent);
		AudioFrame High = FMath::Max(ExternRange, CurrentRange.GetUpperBoundValue() - WheelDelta * (1 - MousePosPercent));
		
		// High = FMath::Min(High, GetDurationWithExtern()); // 不限制缩放的最大范围
		// 限制最小范围
		if (WheelDelta.Pos > 0 && High - Low <= MinRange)
		{
			const AudioFrame Mid = (Low + High) / 2.0;
			Low = Mid - MinRange.Pos / 2;
			High = Mid + MinRange.Pos / 2;
		}
		TargetFrameRange = TRange<AudioFrame>(Low, High);
	}
	
	if (HorizonScrolling)
	{
		const TRange<AudioFrame>& CurrentRange = TargetFrameRange;
		const AudioFrame WheelDelta = InMouseEvent.GetWheelDelta() * GetScalerLevel();
		const AudioFrame Size = CurrentRange.Size<AudioFrame>();
		const AudioFrame Low = FMath::Max(0.f, CurrentRange.GetLowerBoundValue() - WheelDelta);
		const AudioFrame High = FMath::Max(Low + Size, CurrentRange.GetUpperBoundValue() - WheelDelta);
		
		TargetFrameRange = TRange<AudioFrame>(Low, High);
	}
	
	return SCompoundWidget::OnMouseWheel(MyGeometry, InMouseEvent);
}

AudioFrame SPlayList::GetScalerLevel()
{
	const MidiTick Scaler = PlayListPanel->GetPixelToSampleScaler().Ticks();
	const FMidiSequencer& Sequencer = FMidiSequencer::Get();
	const MidiTick Bar = Sequencer.GetBeat();
	return Bar;
	
	if (Scaler > Bar)
		return Bar;
	const MidiTick Beat = Sequencer.GetBeat();
	if (Scaler > Beat)
		return Beat;
	return Sequencer.GetTicksPerQuarter();
}


END_SLATE_FUNCTION_BUILD_OPTIMIZATION