// Copyright Epic Games, Inc. All Rights Reserved.

#include "Tools/UEdMode.h"
#include "EditorModeTools.h"
#include "EditorViewportClient.h"
#include "Framework/Application/SlateApplication.h"
#include "CanvasItem.h"
#include "Engine/StaticMeshActor.h"
#include "Engine/Selection.h"
#include "EngineUtils.h"
#include "EditorModeManager.h"
#include "EditorModes.h"
#include "StaticMeshResources.h"
#include "Toolkits/BaseToolkit.h"
#include "EdModeInteractiveToolsContext.h"
#include "CanvasTypes.h"
#include "ScopedTransaction.h"
#include "Tools/EditorToolAssetAPI.h"
#include "Editor.h"
#include "Toolkits/ToolkitManager.h"
#include "Materials/Material.h"
#include "Materials/MaterialInterface.h"
#include "LevelEditorViewport.h"
#include "InteractiveToolManager.h"
#include "InteractiveToolObjects.h"
#include "Editor/EditorEngine.h"
#include "GameFramework/Actor.h"

/** Hit proxy used for editable properties */
struct HPropertyWidgetProxyTools: public HHitProxy
{
    DECLARE_HIT_PROXY();

    /** Name of property this is the widget for */
    FString PropertyName;

    /** If the property is an array property, the index into that array that this widget is for */
    int32 PropertyIndex;

    /** This property is a transform */
    bool bPropertyIsTransform;

    HPropertyWidgetProxyTools(FString InPropertyName, int32 InPropertyIndex, bool bInPropertyIsTransform)
        : HHitProxy(HPP_Foreground), PropertyName(InPropertyName), PropertyIndex(InPropertyIndex), bPropertyIsTransform(bInPropertyIsTransform)
    {}

    /** Show cursor as cross when over this handle */
    virtual EMouseCursor::Type GetMouseCursor() override
    {
        return EMouseCursor::Crosshairs;
    }
};

IMPLEMENT_HIT_PROXY(HPropertyWidgetProxyTools, HHitProxy);

//////////////////////////////////
// UEdMode

UEdMode::UEdMode()
    : bPendingDeletion(false), Owner(nullptr)
{
    bDrawKillZ        = true;
    ToolsContext      = nullptr;
    ToolsContextClass = UEdModeInteractiveToolsContext::StaticClass();
    ToolCommandList   = MakeShareable(new FUICommandList);
}

void UEdMode::Initialize()
{
}

bool UEdMode::MouseEnter(FEditorViewportClient* ViewportClient, FViewport* Viewport, int32 x, int32 y)
{
    if (ToolsContext->MouseEnter(ViewportClient, Viewport, x, y))
    {
        return true;
    }

    return false;
}

bool UEdMode::MouseLeave(FEditorViewportClient* ViewportClient, FViewport* Viewport)
{
    if (ToolsContext->MouseLeave(ViewportClient, Viewport))
    {
        return true;
    }

    return false;
}

bool UEdMode::MouseMove(FEditorViewportClient* ViewportClient, FViewport* Viewport, int32 x, int32 y)
{
    if (ToolsContext->MouseMove(ViewportClient, Viewport, x, y))
    {
        return true;
    }

    return false;
}

bool UEdMode::ReceivedFocus(FEditorViewportClient* ViewportClient, FViewport* Viewport)
{
    return false;
}

bool UEdMode::LostFocus(FEditorViewportClient* ViewportClient, FViewport* Viewport)
{
    return false;
}

bool UEdMode::CapturedMouseMove(FEditorViewportClient* InViewportClient, FViewport* InViewport, int32 InMouseX, int32 InMouseY)
{
    // if alt is down we will not allow client to see this event
    if (ToolsContext->CapturedMouseMove(InViewportClient, InViewport, InMouseX, InMouseY))
    {
        return true;
    }

    return false;
}

bool UEdMode::InputKey(FEditorViewportClient* ViewportClient, FViewport* Viewport, FKey Key, EInputEvent Event)
{
    if (!Viewport)
    {
        return false;
    }

    if (ToolsContext->InputKey(ViewportClient, Viewport, Key, Event))
    {
        return true;
    }

    if (Event != IE_Released)
    {
        if (ToolCommandList->ProcessCommandBindings(Key, FSlateApplication::Get().GetModifierKeys(), false /*Event == IE_Repeat*/))
        {
            return true;
        }
    }
    // Next pass input to the mode toolkit
    if (Toolkit.IsValid() && ((Event == IE_Pressed) || (Event == IE_Repeat)))
    {
        if (Toolkit->GetToolkitCommands()->ProcessCommandBindings(Key, FSlateApplication::Get().GetModifierKeys(), (Event == IE_Repeat)))
        {
            return true;
        }
    }

    // Finally, pass input up to selected actors if not in a tool mode
    TArray<AActor*> SelectedActors;
    Owner->GetSelectedActors()->GetSelectedObjects<AActor>(SelectedActors);

    for (TArray<AActor*>::TIterator It(SelectedActors); It; ++It)
    {
        // Tell the object we've had a key press
        (*It)->EditorKeyPressed(Key, Event);
    }

    return false;
}

bool UEdMode::InputAxis(FEditorViewportClient* InViewportClient, FViewport* Viewport, int32 ControllerId, FKey Key, float Delta, float DeltaTime)
{
    return false;
}

bool UEdMode::InputDelta(FEditorViewportClient* InViewportClient, FViewport* InViewport, FVector& InDrag, FRotator& InRot, FVector& InScale)
{
    return false;
}

void UEdMode::SelectNone()
{
    GEditor->SelectNone(true, true);
}

bool UEdMode::ProcessEditDelete()
{
    if (ToolsContext->ProcessEditDelete())
    {
        return true;
    }

    return false;
}

void UEdMode::Tick(FEditorViewportClient* ViewportClient, float DeltaTime)
{
    // Tick the ToolsContext
    ToolsContext->Tick(ViewportClient, DeltaTime);
}

bool UEdMode::HandleClick(FEditorViewportClient* InViewportClient, HHitProxy* HitProxy, const FViewportClick& Click)
{
    return false;
}

void UEdMode::Enter()
{
    // Update components for selected actors, in case the mode we just exited
    // was hijacking selection events selection and not updating components.
    for (FSelectionIterator It(*Owner->GetSelectedActors()); It; ++It)
    {
        AActor* SelectedActor = CastChecked<AActor>(*It);
        SelectedActor->MarkComponentsRenderStateDirty();
    }

    bPendingDeletion = false;

    // initialize the adapter that attaches the ToolsContext to this FEdMode
    ToolsContext = NewObject<UEdModeInteractiveToolsContext>(GetTransientPackage(), ToolsContextClass.Get(), TEXT("ToolsContext"), RF_Transient);
    ToolsContext->InitializeContextWithEditorModeManager(GetModeManager());

    GetToolManager()->OnToolStarted.AddUObject(this, &UEdMode::OnToolStarted);
    GetToolManager()->OnToolEnded.AddUObject(this, &UEdMode::OnToolEnded);

    // Now that the context is ready, make the toolkit
    CreateToolkit();

    FEditorDelegates::EditorModeIDEnter.Broadcast(GetID());
}

void UEdMode::RegisterTool(TSharedPtr<FUICommandInfo> UICommand, FString ToolIdentifier, UInteractiveToolBuilder* Builder)
{
    const TSharedRef<FUICommandList>& CommandList = Toolkit->GetToolkitCommands();
    ToolsContext->ToolManager->RegisterToolType(ToolIdentifier, Builder);
    CommandList->MapAction(UICommand,
                           FExecuteAction::CreateLambda([this, ToolIdentifier]()
                                                        {
                                                            this->ToolsContext->StartTool(ToolIdentifier);
                                                        }),
                           FCanExecuteAction::CreateLambda([this, ToolIdentifier]()
                                                           {
                                                               return this->ToolsContext->ToolManager->CanActivateTool(EToolSide::Mouse, ToolIdentifier);
                                                           }),
                           FIsActionChecked::CreateLambda([this, Builder]()
                                                          {
                                                              return this->ToolsContext->IsToolBuilderActive(EToolSide::Mouse, Builder);
                                                          }));
}

void UEdMode::Exit()
{
    GetToolManager()->OnToolStarted.RemoveAll(this);
    GetToolManager()->OnToolEnded.RemoveAll(this);

    ToolsContext->ShutdownContext();
    ToolsContext = nullptr;

    if (Toolkit.IsValid())
    {
        FToolkitManager::Get().CloseToolkit(Toolkit.ToSharedRef());
        Toolkit.Reset();
    }

    FEditorDelegates::EditorModeIDExit.Broadcast(GetID());
}

UTexture2D* UEdMode::GetVertexTexture()
{
    return GEngine->DefaultBSPVertexTexture;
}

void UEdMode::Render(const FSceneView* View, FViewport* Viewport, FPrimitiveDrawInterface* PDI)
{
    // give ToolsContext a chance to render
    if (ToolsContext != nullptr)
    {
        ToolsContext->Render(View, Viewport, PDI);
    }
}

void UEdMode::DrawHUD(FEditorViewportClient* ViewportClient, FViewport* Viewport, const FSceneView* View, FCanvas* Canvas)
{
    // give ToolsContext a chance to draw in screen space
    if (ToolsContext != nullptr)
    {
        ToolsContext->DrawHUD(ViewportClient, Viewport, View, Canvas);
    }

    // Render the drag tool.
    ViewportClient->RenderDragTool(View, Canvas);

    if (ViewportClient->IsPerspective() && GetDefault<ULevelEditorViewportSettings>()->bHighlightWithBrackets)
    {
        DrawBrackets(ViewportClient, Viewport, View, Canvas);
    }

    // If this viewport doesn't show mode widgets, leave.
    if (!(ViewportClient->EngineShowFlags.ModeWidgets))
    {
        return;
    }

    // Clear Hit proxies
    const bool bIsHitTesting = Canvas->IsHitTesting();
    if (!bIsHitTesting)
    {
        Canvas->SetHitProxy(NULL);
    }

    // Draw vertices for selected BSP brushes and static meshes if the large vertices show flag is set.
    if (!ViewportClient->bDrawVertices)
    {
        return;
    }

    const bool bLargeVertices    = View->Family->EngineShowFlags.LargeVertices;
    const bool bShowBrushes      = View->Family->EngineShowFlags.Brushes;
    const bool bShowBSP          = View->Family->EngineShowFlags.BSP;
    const bool bShowBuilderBrush = View->Family->EngineShowFlags.BuilderBrush != 0;

    UTexture2D* VertexTexture    = GetVertexTexture();
    const float TextureSizeX     = VertexTexture->GetSizeX() * (bLargeVertices ? 1.0f : 0.5f);
    const float TextureSizeY     = VertexTexture->GetSizeY() * (bLargeVertices ? 1.0f : 0.5f);

    // Temporaries.
    TArray<FVector> Vertices;

    for (FSelectionIterator It(*Owner->GetSelectedActors()); It; ++It)
    {
        AActor* SelectedActor = static_cast<AActor*>(*It);
        checkSlow(SelectedActor->IsA(AActor::StaticClass()));

        if (bLargeVertices)
        {
            FCanvasItemTestbed::bTestState = !FCanvasItemTestbed::bTestState;

            // Static mesh vertices
            AStaticMeshActor* Actor = Cast<AStaticMeshActor>(SelectedActor);
            if (Actor && Actor->GetStaticMeshComponent() && Actor->GetStaticMeshComponent()->GetStaticMesh() && Actor->GetStaticMeshComponent()->GetStaticMesh()->GetRenderData())
            {
                FTransform ActorToWorld = Actor->ActorToWorld();
                Vertices.Empty();
                const FPositionVertexBuffer& VertexBuffer = Actor->GetStaticMeshComponent()->GetStaticMesh()->GetRenderData()->LODResources[0].VertexBuffers.PositionVertexBuffer;
                for (uint32 i = 0; i < VertexBuffer.GetNumVertices(); i++)
                {
                    Vertices.AddUnique(ActorToWorld.TransformPosition(VertexBuffer.VertexPosition(i)));
                }

                const float InvDpiScale = 1.0f / Canvas->GetDPIScale();

                FCanvasTileItem TileItem(FVector2D(0.0f, 0.0f), FVector2D(0.0f, 0.0f), FLinearColor::White);
                TileItem.BlendMode = SE_BLEND_Translucent;
                for (int32 VertexIndex = 0; VertexIndex < Vertices.Num(); ++VertexIndex)
                {
                    const FVector& Vertex = Vertices[VertexIndex];
                    FVector2D PixelLocation;
                    if (View->ScreenToPixel(View->WorldToScreen(Vertex), PixelLocation))
                    {
                        PixelLocation *= InvDpiScale;

                        const bool bOutside =
                            PixelLocation.X < 0.0f || PixelLocation.X > View->UnscaledViewRect.Width() * InvDpiScale ||
                            PixelLocation.Y < 0.0f || PixelLocation.Y > View->UnscaledViewRect.Height() * InvDpiScale;
                        if (!bOutside)
                        {
                            const float X = PixelLocation.X - (TextureSizeX / 2);
                            const float Y = PixelLocation.Y - (TextureSizeY / 2);
                            if (bIsHitTesting)
                            {
                                Canvas->SetHitProxy(new HStaticMeshVert(Actor, Vertex));
                            }
                            TileItem.Texture = VertexTexture->Resource;

                            TileItem.Size    = FVector2D(TextureSizeX, TextureSizeY);
                            Canvas->DrawItem(TileItem, FVector2D(X, Y));
                            if (bIsHitTesting)
                            {
                                Canvas->SetHitProxy(NULL);
                            }
                        }
                    }
                }
            }
        }
    }
}

void UEdMode::DrawBrackets(FEditorViewportClient* ViewportClient, FViewport* Viewport, const FSceneView* View, FCanvas* Canvas)
{
    USelection& SelectedActors = *Owner->GetSelectedActors();
    for (int32 CurSelectedActorIndex = 0; CurSelectedActorIndex < SelectedActors.Num(); ++CurSelectedActorIndex)
    {
        AActor* SelectedActor = Cast<AActor>(SelectedActors.GetSelectedObject(CurSelectedActorIndex));
        if (SelectedActor != NULL)
        {
            // Draw a bracket for selected "paintable" static mesh actors
            const bool bIsValidActor = (Cast<AStaticMeshActor>(SelectedActor) != NULL);

            const FLinearColor SelectedActorBoxColor(0.6f, 0.6f, 1.0f);
            const bool bDrawBracket = bIsValidActor;
            ViewportClient->DrawActorScreenSpaceBoundingBox(Canvas, View, Viewport, SelectedActor, SelectedActorBoxColor, bDrawBracket);
        }
    }
}

bool UEdMode::UsesToolkits() const
{
    return true;
}

UWorld* UEdMode::GetWorld() const
{
    return Owner->GetWorld();
}

class FEditorModeTools* UEdMode::GetModeManager() const
{
    return Owner;
}

bool UEdMode::StartTracking(FEditorViewportClient* InViewportClient, FViewport* InViewport)
{
    if (ToolsContext->StartTracking(InViewportClient, InViewport))
    {
        return true;
    }

    return false;
}

bool UEdMode::EndTracking(FEditorViewportClient* InViewportClient, FViewport* InViewport)
{
    if (ToolsContext->EndTracking(InViewportClient, InViewport))
    {
        return true;
    }

    return false;
}

AActor* UEdMode::GetFirstSelectedActorInstance() const
{
    return Owner->GetSelectedActors()->GetTop<AActor>();
}

UInteractiveToolManager* UEdMode::GetToolManager() const
{
    return ToolsContext->ToolManager;
}

void UEdMode::CreateToolkit()
{
    if (!Toolkit.IsValid())
    {
        Toolkit = MakeShareable(new FModeToolkit);
        Toolkit->Init(Owner->GetToolkitHost());
    }

    UClass* LoadedSettingsObject = SettingsClass.LoadSynchronous();
    SettingsObject               = NewObject<UObject>(this, LoadedSettingsObject);
    if (SettingsObject)
    {
        Toolkit->SetModeSettingsObject(SettingsObject);
    }
}

bool UEdMode::IsSnapRotationEnabled()
{
    return GetDefault<ULevelEditorViewportSettings>()->RotGridEnabled;
}