// ©2023 Batty Bovine Productions, LLC. All Rights Reserved.


#include "ComboActionTreeSolveLayoutStrategy.h"

#include "ComboActionGraph.h"

#include "Ed/EdComboActionGraph.h"
#include "Ed/EdComboActionGraphNode.h"
#include "Nodes/ComboActionGraphNode.h"
#include "Settings/ComboActionGraphEditorSettings.h"


void UComboActionTreeSolveLayoutStrategy::Layout(UEdGraph *InEdGraph)
{
	this->EdGraph = Cast<UEdComboActionGraph>(InEdGraph);
	check(this->EdGraph != nullptr);

	this->EdGraph->RebuildComboActionGraph();
	this->Graph = this->EdGraph->GetComboActionGraph();
	check(this->Graph != nullptr);

	bool bFirstPassOnly = false;

	if (this->Settings == nullptr)
	{
		this->Settings = GetMutableDefault<UComboActionGraphEditorSettings>();
	}
	
	if (this->Settings != nullptr)
	{
		this->OptimalDistance = this->Settings->GetOptimalDistance();
		this->MaxIteration = this->Settings->GetMaxIteration();
		bFirstPassOnly = this->Settings->IsFirstPassOnly();
	}

	FVector2D Anchor(0.f, 0.f);
	for (UComboActionGraphNode *RootNode : this->Graph->RootNodes)
	{
		this->InitPass(RootNode, Anchor);

		if (!bFirstPassOnly)
		{
			for (int32 j = 0; j < this->MaxIteration; ++j)
			{
				bool HasConflict = this->ResolveConflictPass(RootNode);
				if (!HasConflict)
				{
					break;
				}
			}
		}
	}

	for (int32 i = 0; i < Graph->RootNodes.Num(); i++)
	{
		for (int32 j = 0; j < i; j++)
		{
			this->ResolveConflict(Graph->RootNodes[j], Graph->RootNodes[i]);
		}
	}
}

void UComboActionTreeSolveLayoutStrategy::InitPass(UComboActionGraphNode *RootNode, const FVector2D &Anchor)
{
	UEdComboActionGraphNode *EdNode_RootNode = this->EdGraph->NodeMap[RootNode];

	FVector2D ChildAnchor(FVector2D(0.0f, this->GetNodeHeight(EdNode_RootNode) + this->OptimalDistance + Anchor.Y));
	for (int32 i = 0; i < RootNode->ChildNodes.Num(); i++)
	{
		UComboActionGraphNode *Child = RootNode->ChildNodes[i];
		UEdComboActionGraphNode *EdNode_ChildNode = this->EdGraph->NodeMap[Child];
		if (i > 0)
		{
			UComboActionGraphNode *PreChild = RootNode->ChildNodes[i - 1];
			UEdComboActionGraphNode *EdNode_PreChildNode = this->EdGraph->NodeMap[PreChild];
			ChildAnchor.X += this->OptimalDistance + this->GetNodeWidth(EdNode_PreChildNode) / 2;
		}
		ChildAnchor.X += this->GetNodeWidth(EdNode_ChildNode) / 2;
		this->InitPass(Child, ChildAnchor);
	}
	
	float NodeWidth = this->GetNodeWidth(EdNode_RootNode);

	EdNode_RootNode->NodePosY = Anchor.Y;
	if (RootNode->ChildNodes.Num() == 0)
	{
		EdNode_RootNode->NodePosX = Anchor.X - NodeWidth / 2;
	}
	else
	{
		this->UpdateParentNodePosition(RootNode);
	}
}

bool UComboActionTreeSolveLayoutStrategy::ResolveConflictPass(UComboActionGraphNode *Node)
{
	bool HasConflict = false;
	for (int32 i = 0; i < Node->ChildNodes.Num(); ++i)
	{
		UComboActionGraphNode *Child = Node->ChildNodes[i];
		if (this->ResolveConflictPass(Child))
		{
			HasConflict = true;
		}
	}

	for (const UComboActionGraphNode *ParentNode : Node->ParentNodes)
	{
		for (UComboActionGraphNode *LeftSibling : ParentNode->ChildNodes)
		{
			if (LeftSibling == Node)
			{
				break;
			}
			if (this->ResolveConflict(LeftSibling, Node))
			{
				HasConflict = true;
			}
		}
	}

	return HasConflict;
}

bool UComboActionTreeSolveLayoutStrategy::ResolveConflict(UComboActionGraphNode *LRoot, UComboActionGraphNode *RRoot)
{
	TArray<UEdComboActionGraphNode*> RightContour, LeftContour;

	this->GetRightContour(LRoot, 0, RightContour);
	this->GetLeftContour(RRoot, 0, LeftContour);

	int32 MaxOverlapDistance = 0;
	int32 Num = FMath::Min(LeftContour.Num(), RightContour.Num());
	for (int32 i = 0; i < Num; ++i)
	{
		if (RightContour.Contains(LeftContour[i]) || LeftContour.Contains(RightContour[i]))
			break;

		int32 RightBound = RightContour[i]->NodePosX + this->GetNodeWidth(RightContour[i]);
		int32 LeftBound = LeftContour[i]->NodePosX;
		int32 Distance = RightBound + OptimalDistance - LeftBound;
		if (Distance > MaxOverlapDistance)
		{
			MaxOverlapDistance = Distance;
		}
	}

	if (MaxOverlapDistance > 0)
	{
		this->ShiftSubTree(RRoot, FVector2D(MaxOverlapDistance, 0.f));

		TArray<UComboActionGraphNode*> ParentNodes = RRoot->ParentNodes;
		TArray<UComboActionGraphNode*> NextParentNodes;
		while (ParentNodes.Num() != 0)
		{
			for (int32 i = 0; i < ParentNodes.Num(); ++i)
			{
				UpdateParentNodePosition(ParentNodes[i]);

				NextParentNodes.Append(ParentNodes[i]->ParentNodes);
			}

			ParentNodes = NextParentNodes;
			NextParentNodes.Reset();
		}

		return true;
	}
	
	return false;
}

void UComboActionTreeSolveLayoutStrategy::GetLeftContour(UComboActionGraphNode *RootNode, int32 Level, TArray<UEdComboActionGraphNode*> &Contour)
{
	UEdComboActionGraphNode *EdNode_Node = this->EdGraph->NodeMap[RootNode];
	if (Level >= Contour.Num())
	{
		Contour.Add(EdNode_Node);
	}
	else if (EdNode_Node->NodePosX < Contour[Level]->NodePosX)
	{
		Contour[Level] = EdNode_Node;
	}

	for (UComboActionGraphNode *Child : RootNode->ChildNodes)
	{
		this->GetLeftContour(Child, Level + 1, Contour);
	}
}

void UComboActionTreeSolveLayoutStrategy::GetRightContour(UComboActionGraphNode *RootNode, int32 Level, TArray<UEdComboActionGraphNode*> &Contour)
{
	UEdComboActionGraphNode *EdNode_Node = this->EdGraph->NodeMap[RootNode];
	if (Level >= Contour.Num())
	{
		Contour.Add(EdNode_Node);
	}
	else if (EdNode_Node->NodePosX + this->GetNodeWidth(EdNode_Node) > Contour[Level]->NodePosX + this->GetNodeWidth(Contour[Level]))
	{
		Contour[Level] = EdNode_Node;
	}

	for (UComboActionGraphNode *Child : RootNode->ChildNodes)
	{
		this->GetRightContour(Child, Level + 1, Contour);
	}
}

void UComboActionTreeSolveLayoutStrategy::ShiftSubTree(UComboActionGraphNode *RootNode, const FVector2D &Offset)
{
	UEdComboActionGraphNode *EdNode_Node = this->EdGraph->NodeMap[RootNode];
	EdNode_Node->NodePosX += Offset.X;
	EdNode_Node->NodePosY += Offset.Y;

	for (UComboActionGraphNode *Child : RootNode->ChildNodes)
	{
		if (Child->ParentNodes[0] == RootNode)
		{
			this->ShiftSubTree(Child, Offset);
		}
	}
}

void UComboActionTreeSolveLayoutStrategy::UpdateParentNodePosition(UComboActionGraphNode *RootNode)
{
	UEdComboActionGraphNode *EdNode_ParentNode = this->EdGraph->NodeMap[RootNode];
	if (RootNode->ChildNodes.Num() % 2 == 0)
	{
		UEdComboActionGraphNode *FirstChild = this->EdGraph->NodeMap[RootNode->ChildNodes[0]];
		UEdComboActionGraphNode *LastChild = this->EdGraph->NodeMap[RootNode->ChildNodes.Last()];
		float LeftBound = FirstChild->NodePosX;
		float RightBound = LastChild->NodePosX + this->GetNodeWidth(LastChild);
		EdNode_ParentNode->NodePosX = (LeftBound + RightBound) / 2 - this->GetNodeWidth(EdNode_ParentNode) / 2;
	}
	else
	{
		UEdComboActionGraphNode *MidChild = this->EdGraph->NodeMap[RootNode->ChildNodes[RootNode->ChildNodes.Num() / 2]];
		EdNode_ParentNode->NodePosX = MidChild->NodePosX + this->GetNodeWidth(MidChild) / 2 - this->GetNodeWidth(EdNode_ParentNode) / 2;
	}
}