// Copyright 1998-2014 Epic Games, Inc. All Rights Reserved.

#include "MergePrivatePCH.h"
#include "DiffResults.h"
#include "GraphDiffControl.h"
#include "SMergeGraphView.h"

#define LOCTEXT_NAMESPACE "SMergeGraphView"

// This cludge is used to move arrays of structures into arrays of 
// shared ptrs of those structures. It is used because SListView
// does not support arrays of values:
template< typename T >
TArray< TSharedPtr<T> > HackToShared(const TArray<T>& Values)
{
	TArray< TSharedPtr<T> > Ret;
	for (const auto& Value : Values)
	{
		Ret.Add(TSharedPtr<T>(new T(Value)));
	}
	return Ret;
}

struct FBlueprintRevPair
{
	FBlueprintRevPair(const UBlueprint* InBlueprint, const FRevisionInfo& InRevData)
	: Blueprint(InBlueprint)
	, RevData(InRevData)
	{
	}

	const UBlueprint* Blueprint;
	const FRevisionInfo& RevData;
};

struct FMergeGraphRowEntry
{
	FString GraphName;

	// These lists contain shared ptrs because they are displayed by a
	// SListView, and it currently does not support lists of values.
	TArray< TSharedPtr<FDiffSingleResult> > RemoteDifferences;
	TArray< TSharedPtr<FDiffSingleResult> > LocalDifferences;

	bool bExistsInRemote;
	bool bExistsInBase;
	bool bExistsInLocal;
};

static UEdGraph* FindGraphByName(UBlueprint const& FromBlueprint, const FString& GraphName)
{
	TArray<UEdGraph*> Graphs;
	FromBlueprint.GetAllGraphs(Graphs);

	UEdGraph* Ret = NULL;
	if (UEdGraph** Result = Graphs.FindByPredicate(FMatchName(GraphName)))
	{
		Ret = *Result;
	}
	return Ret;
}

static FDiffPanel InitializePanel(const FBlueprintRevPair& BlueprintRevPair)
{
	FDiffPanel Ret;
	Ret.Blueprint = BlueprintRevPair.Blueprint;
	SAssignNew(Ret.GraphEditorBorder, SBorder)
		.VAlign(VAlign_Fill)
		[
			SBlueprintDiff::DefaultEmptyPanel()
		];
	Ret.RevisionInfo = BlueprintRevPair.RevData;
	Ret.bShowAssetName = false;
	return Ret;
}

// @todo doc: can i avoid shared ptrs for individual entries?
static TArray< TSharedPtr<FMergeGraphRowEntry> > GenerateDiffListItems(const FBlueprintRevPair& RemoteBlueprint, const FBlueprintRevPair& BaseBlueprint, const FBlueprintRevPair& LocalBlueprint)
{
	// Index all the graphs by name, we use the name of the graph as the 
	// basis of comparison between the various versions of the blueprint.
	TMap< FString, UEdGraph* > RemoteGraphMap, BaseGraphMap, LocalGraphMap;
	// We also want the set of all graph names in these blueprints, so that we 
	// can iterate over every graph.
	TSet< FString > AllGraphNames;
	{
		TArray<UEdGraph*> GraphsRemote, GraphsBase, GraphsLocal;
		RemoteBlueprint.Blueprint->GetAllGraphs(GraphsRemote);
		BaseBlueprint.Blueprint->GetAllGraphs(GraphsBase);
		LocalBlueprint.Blueprint->GetAllGraphs(GraphsLocal);

		const auto ToMap = [&AllGraphNames](const TArray<UEdGraph*>& InList, TMap<FString, UEdGraph*>& OutMap)
		{
			for (auto Graph : InList)
			{
				OutMap.Add(Graph->GetName(), Graph);
				AllGraphNames.Add(Graph->GetName());
			}
		};
		ToMap(GraphsRemote, RemoteGraphMap);
		ToMap(GraphsBase, BaseGraphMap);
		ToMap(GraphsLocal, LocalGraphMap);
	}

	TArray< TSharedPtr<FMergeGraphRowEntry> > Ret;
	{
		const auto GenerateDifferences = [](UEdGraph* GraphNew, UEdGraph** GraphOld)
		{
			TArray<FDiffSingleResult> Results;
			FGraphDiffControl::DiffGraphs(GraphOld ? *GraphOld : NULL, GraphNew, Results);
			return Results;
		};

		for (const auto& GraphName : AllGraphNames)
		{
			TArray< FDiffSingleResult > RemoteDifferences;
			TArray< FDiffSingleResult > LocalDifferences;
			bool bExistsInRemote, bExistsInBase, bExistsInLocal;

			{
				UEdGraph** RemoteGraph = RemoteGraphMap.Find(GraphName);
				UEdGraph** BaseGraph = BaseGraphMap.Find(GraphName);
				UEdGraph** LocalGraph = LocalGraphMap.Find(GraphName);

				if (RemoteGraph)
				{
					RemoteDifferences = GenerateDifferences(*RemoteGraph, BaseGraph);
				}

				if (LocalGraph)
				{
					LocalDifferences = GenerateDifferences(*LocalGraph, BaseGraph);
				}

				bExistsInRemote = RemoteGraph != NULL;
				bExistsInBase = BaseGraph != NULL;
				bExistsInLocal = LocalGraph != NULL;
			}

			FMergeGraphRowEntry NewEntry = {
				GraphName,
				HackToShared(RemoteDifferences),
				HackToShared(LocalDifferences),
				bExistsInRemote,
				bExistsInBase,
				bExistsInLocal
			};
			Ret.Add(TSharedPtr<FMergeGraphRowEntry>(new FMergeGraphRowEntry(NewEntry)));
		}
	}

	return Ret;
}

static void LockViews(TArray<FDiffPanel>& Views, bool bAreLocked)
{
	for (auto& Panel : Views)
	{
		auto GraphEditor = Panel.GraphEditor.Pin();
		if (GraphEditor.IsValid())
		{
			// lock this panel to ever other panel:
			for (auto& OtherPanel : Views)
			{
				auto OtherGraphEditor = OtherPanel.GraphEditor.Pin();
				if (OtherGraphEditor.IsValid() &&
					OtherGraphEditor != GraphEditor)
				{
					if (bAreLocked)
					{
						GraphEditor->LockToGraphEditor(OtherGraphEditor);
					}
					else
					{
						GraphEditor->UnlockFromGraphEditor(OtherGraphEditor);
					}
				}
			}
		}
	}
}

FDiffPanel& GetDiffPanelForNode(const UEdGraphNode& Node, TArray< FDiffPanel >& Panels)
{
	for (auto& Panel : Panels)
	{
		auto GraphEditor = Panel.GraphEditor.Pin();
		if (GraphEditor.IsValid())
		{
			if (Node.GetGraph() == GraphEditor->GetCurrentGraph())
			{
				return Panel;
			}
		}
	}
	checkf(false, TEXT("Looking for node %s but it cannot be found in provided panels"), *Node.GetName());
	static FDiffPanel Default;
	return Default;
}

// Some color constants used by the merge view:
const FLinearColor MergeBlue = FLinearColor(0.3f, 0.3f, 1.f);
const FLinearColor MergeRed = FLinearColor(1.0f, 0.2f, 0.3f);
const FLinearColor MergeYellow = FLinearColor::Yellow;
const FLinearColor MergeWhite = FLinearColor::White;

void SMergeGraphView::Construct(const FArguments InArgs, const FBlueprintMergeData& InData)
{
	Data = InData;
	bViewsAreLocked = true;

	TArray<FBlueprintRevPair> BlueprintsForDisplay;
	// EMergeParticipant::MERGE_PARTICIPANT_REMOTE
	BlueprintsForDisplay.Add(FBlueprintRevPair(InData.BlueprintNew, InData.RevisionNew));
	// EMergeParticipant::MERGE_PARTICIPANT_BASE
	BlueprintsForDisplay.Add(FBlueprintRevPair(InData.BlueprintBase, InData.RevisionBase));
	// EMergeParticipant::MERGE_PARTICIPANT_LOCAL
	BlueprintsForDisplay.Add(FBlueprintRevPair(InData.BlueprintLocal, FRevisionInfo()));

	for (const auto& BlueprintRevPair : BlueprintsForDisplay)
	{
		DiffPanels.Add(InitializePanel(BlueprintRevPair));
	}

	TSharedRef<SSplitter> PanelContainer = SNew(SSplitter);
	for (const auto& Panel : DiffPanels)
	{
		PanelContainer->AddSlot()[Panel.GraphEditorBorder.ToSharedRef()];
	}

	DifferencesFromBase = GenerateDiffListItems(BlueprintsForDisplay[EMergeParticipant::MERGE_PARTICIPANT_REMOTE]
		, BlueprintsForDisplay[EMergeParticipant::MERGE_PARTICIPANT_BASE]
		, BlueprintsForDisplay[EMergeParticipant::MERGE_PARTICIPANT_LOCAL]);

	// This is the function we'll use to generate a row in the control that lists all the available graphs:
	const auto RowGenerator = [](TSharedPtr<FMergeGraphRowEntry> ParamItem, const TSharedRef<STableViewBase>& OwnerTable) -> TSharedRef<ITableRow>
	{
		// blue indicates added, red indicates changed, yellow indicates removed, white indicates no change:
		const auto ComputeColorForRevision = [](bool bExistsInBase, bool bExistsInThisRevision, bool bHasChangesInThisRevision) -> FLinearColor
		{
			if (bExistsInBase)
			{
				if (!bExistsInThisRevision)
				{
					return MergeYellow;
				}
				else if (bHasChangesInThisRevision)
				{
					return MergeRed;
				}
			}
			if (!bExistsInBase)
			{
				if (bExistsInThisRevision)
				{
					return MergeBlue;
				}
			}

			return MergeWhite;
		};

		FLinearColor RemoteColor = ComputeColorForRevision(ParamItem->bExistsInBase, ParamItem->bExistsInRemote, ParamItem->RemoteDifferences.Num() != 0);
		FLinearColor BaseColor = ComputeColorForRevision(ParamItem->bExistsInBase, ParamItem->bExistsInBase, false);
		FLinearColor LocalColor = ComputeColorForRevision(ParamItem->bExistsInBase, ParamItem->bExistsInLocal, ParamItem->LocalDifferences.Num() != 0);

		const auto Box = [](bool bIsPresent, FLinearColor Color) -> SHorizontalBox::FSlot&
		{
			return SHorizontalBox::Slot()
				.AutoWidth()
				.HAlign(HAlign_Right)
				.VAlign(VAlign_Center)
				.MaxWidth(8.0f)
				[
					SNew(SImage)
					.ColorAndOpacity(Color)
					.Image(bIsPresent ? FEditorStyle::GetBrush("BlueprintDif.HasGraph") : FEditorStyle::GetBrush("BlueprintDif.MissingGraph"))
				];
		};

		return SNew(STableRow< TSharedPtr<FMergeGraphRowEntry> >, OwnerTable)
			.ToolTipText(LOCTEXT("MergeGraphsDifferentText", "@todo doc"))
			.Content()
			[
				SNew(SHorizontalBox)
				+ SHorizontalBox::Slot()
				[
					SNew(STextBlock)
					.ColorAndOpacity(FLinearColor::White)
					.Text(ParamItem->GraphName)
				]
				+ Box(ParamItem->bExistsInRemote, RemoteColor)
					+ Box(ParamItem->bExistsInBase, BaseColor)
					+ Box(ParamItem->bExistsInLocal, LocalColor)
			];
	};

	ChildSlot
		[
			SNew(SSplitter)
			.Orientation(Orient_Horizontal)
			+ SSplitter::Slot()
			.Value(0.1f)
			[
				// ToolPanel.GroupBorder is currently what gives this control its dark grey appearance:
				SNew(SBorder)
				.BorderImage(FEditorStyle::GetBrush("NoBorder"))
				.Padding(FMargin(1.0f))
				[
					SNew(SSplitter)
					.Orientation(Orient_Vertical)
					+ SSplitter::Slot()
					.Value(.3f)
					[
						SNew(SBorder)
						.BorderImage(FEditorStyle::GetBrush("ToolPanel.GroupBorder"))
						[
							SNew(SVerticalBox)
							+ SVerticalBox::Slot()
							.AutoHeight()
							.HAlign(HAlign_Left)
							[
								SNew(SButton)
								.OnClicked(this, &SMergeGraphView::OnToggleLockView)
								.Content()
								[
									SNew(SImage)
									.Image(this, &SMergeGraphView::GetLockViewImage)
									.ToolTipText(LOCTEXT("BPDifLock", "Lock the blueprint views?"))
								]
							]
							+ SVerticalBox::Slot()
								[
									SNew(SListView< TSharedPtr<FMergeGraphRowEntry> >)
									.ItemHeight(24)
									.ListItemsSource(&DifferencesFromBase)
									.OnGenerateRow(SListView< TSharedPtr<FMergeGraphRowEntry> >::FOnGenerateRow::CreateStatic(RowGenerator))
									.SelectionMode(ESelectionMode::Single)
									.OnSelectionChanged(this, &SMergeGraphView::OnGraphListSelectionChanged)
								]
						]
					]
					+ SSplitter::Slot()
						.Value(.7f)
						[
							SAssignNew(DiffResultsWidget, SBorder)
							.BorderImage(FEditorStyle::GetBrush("ToolPanel.GroupBorder"))
						]
				]
			]
			+ SSplitter::Slot()
				.Value(0.9f)
				[
					PanelContainer
				]
		];
}

void SMergeGraphView::OnGraphListSelectionChanged(TSharedPtr<FMergeGraphRowEntry> Item, ESelectInfo::Type SelectionType)
{
	if (SelectionType != ESelectInfo::OnMouseClick || !Item.IsValid())
	{
		return;
	}

	FString GraphName = Item->GraphName;

	UEdGraph* GraphRemote = FindGraphByName(*GetRemotePanel().Blueprint, GraphName);
	UEdGraph* GraphBase = FindGraphByName(*GetBasePanel().Blueprint, GraphName);
	UEdGraph* GraphLocal = FindGraphByName(*GetLocalPanel().Blueprint, GraphName);

	GetBasePanel().GeneratePanel(GraphBase, NULL);
	GetRemotePanel().GeneratePanel(GraphRemote, GraphBase);
	GetLocalPanel().GeneratePanel(GraphLocal, GraphBase);

	LockViews(DiffPanels, bViewsAreLocked);

	DiffResultsWidget->SetContent(
		SNew(SListView< TSharedPtr<FDiffSingleResult> >)
		.ItemHeight(24)
		.ListItemsSource(&Item->LocalDifferences)
		.OnGenerateRow(SListView< TSharedPtr<FDiffSingleResult> >::FOnGenerateRow::CreateStatic(
		[](TSharedPtr<FDiffSingleResult> ParamItem, const TSharedRef<STableViewBase>& OwnerTable) -> TSharedRef<ITableRow>
	{
		FDiffResultItem WidgetGenerator(*ParamItem);
		return SNew(STableRow< TSharedPtr<FDiffSingleResult> >, OwnerTable)
			.Content()
			[
				WidgetGenerator.GenerateWidget()
			];
	}
	))
		.SelectionMode(ESelectionMode::Single)
		.OnSelectionChanged(this, &SMergeGraphView::OnDiffListSelectionChanged)
		);
}

void SMergeGraphView::OnDiffListSelectionChanged(TSharedPtr<FDiffSingleResult> Item, ESelectInfo::Type SelectionType)
{
	if (SelectionType != ESelectInfo::OnMouseClick || !Item.IsValid())
	{
		return;
	}

	// Clear graph selection:
	for (auto& Panel : DiffPanels)
	{
		auto GraphEdtiorPtr = Panel.GraphEditor.Pin();
		if (GraphEdtiorPtr.IsValid())
		{
			GraphEdtiorPtr->ClearSelectionSet();
		}
	}

	//focus the graph onto the diff that was clicked on
	if (Item->Pin1)
	{
		GetDiffPanelForNode(*Item->Pin1->GetOwningNode(), DiffPanels).FocusDiff(*Item->Pin1);

		if (Item->Pin2)
		{
			GetDiffPanelForNode(*Item->Pin2->GetOwningNode(), DiffPanels).FocusDiff(*Item->Pin2);
		}
	}
	else if (Item->Node1)
	{
		GetDiffPanelForNode(*Item->Node1, DiffPanels).FocusDiff(*Item->Node1);

		if (Item->Node2)
		{
			GetDiffPanelForNode(*Item->Node2, DiffPanels).FocusDiff(*Item->Node2);
		}
	}
}

FReply SMergeGraphView::OnToggleLockView()
{
	bViewsAreLocked = !bViewsAreLocked;

	LockViews(DiffPanels, bViewsAreLocked);
	return FReply::Handled();
}

const FSlateBrush* SMergeGraphView::GetLockViewImage() const
{
	return bViewsAreLocked ? FEditorStyle::GetBrush("GenericLock") : FEditorStyle::GetBrush("GenericUnlock");
}