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

#pragma once

#include "CoreMinimal.h"

class FEditorViewportSnapping;
class FLevelEditorViewportClient;
class FPrimitiveDrawInterface;
class FSceneView;

class UNREALED_API FSnappingUtils
{
public:
    /**
     * @return true if snapping (translation) to the grid is enabled
     */
    static bool IsSnapToGridEnabled();

    /**
     * @return true if orientation snapping is enabled
     */
    static bool IsRotationSnapEnabled();

    /**
     * @return true if orientation snapping is enabled
     */
    static bool IsScaleSnapEnabled();

    /**
     * @return true if snapping actors to other actors is enabled
     */
    static bool IsSnapToActorEnabled();

    /** Set user setting for actor snap. */
    static void EnableActorSnap(bool bEnable);

    /** Access user setting for distance. Fractional 0.0->100.0 */
    static float GetActorSnapDistance(bool bScalar = false);

    /** Set user setting for distance. Fractional 0.0->100.0 */
    static void SetActorSnapDistance(float Distance);

    /**
     * Attempts to snap the selected actors to the nearest other actor
     *
     * @param DragDelta			The current world space drag amount
     * @param ViewportClient	The viewport client the user is dragging in
     */
    static bool SnapActorsToNearestActor(FVector& DragDelta, FLevelEditorViewportClient* ViewportClient);

    /**
     * Snaps actors to the nearest vertex on another actor
     *
     * @param DragDelta			The current world space drag amount that will be modified to account for snapping to a vertex
     * @param ViewportClient	The viewport client the user is dragging in
     * @return true if anything was snapped
     */
    static bool SnapDraggedActorsToNearestVertex(FVector& DragDelta, FLevelEditorViewportClient* ViewportClient);

    /**
     * Snaps a delta drag movement to the nearest vertex
     *
     * @param BaseLocation		Location that should be snapped before any drag is applied
     * @param DragDelta			Delta drag movement that should be snapped.  This value will be updated such that BaseLocation+DragDelta is the nearest snapped verted
     * @param ViewportClient	The viewport client being dragged in.
     * @return true if anything was snapped
     */
    static bool SnapDragLocationToNearestVertex(const FVector& BaseLocation, FVector& DragDelta, FLevelEditorViewportClient* ViewportClient, bool bIsPivot = false);

    /**
     * Snaps a location to the nearest vertex
     *
     * @param Location			The location to snap
     * @param MouseLocation		The current 2d mouse location.  Vertices closer to the mouse are favored
     * @param ViewportClient	The viewport client being used
     * @param OutVertexNormal	The normal at the closest vertex
     * @return true if anything was snapped
     */
    static bool SnapLocationToNearestVertex(FVector& Location, const FVector2D& MouseLocation, FLevelEditorViewportClient* ViewportClient, FVector& OutVertexNormal, bool bDrawVertHelpers);

    /**
     * Snaps a scale value to the scale grid
     *
     * @param Point	The point to snap.  This value will be modified to account for snapping
     * @param GridBase	Base grid offset
     */
    static void SnapScale(FVector& Point, const FVector& GridBase);

    /**
     * Snaps a point value to the positional grid
     *
     * @param Point	The point to snap.  This value will be modified to account for snapping
     * @param GridBase	Base grid offset
     */
    static void SnapPointToGrid(FVector& Point, const FVector& GridBase);

    /**
     * Snaps a rotator to the rotational grid
     *
     * @param Rotation	The rotator to snap.  This value will be modified to account for snapping
     */
    static void SnapRotatorToGrid(FRotator& Rotation);

    static bool SnapToBSPVertex(FVector& Location, FVector GridBase, FRotator& Rotation);

    /**
     * Clears all vertices being drawn to help a user snap
     *
     * @param bClearImmediatley	true to clear helpers without fading them out
     */
    static void ClearSnappingHelpers(bool bClearImmediately = false);

    /**
     * Draws snapping helpers
     *
     * @param View	The current view of the scene
     * @param PDI	Drawing interface
     */
    static void DrawSnappingHelpers(const FSceneView* View, FPrimitiveDrawInterface* PDI);

    /**
     * Initialize the snapping system
     */
    static void InitEditorSnappingTools();

private:
    /** Built-in editor snap implementation */
    static TSharedPtr<class FEditorViewportSnapping> EditorViewportSnapper;
};