#pragma once
#pragma region CPL License
/*
Nuclex Unreal Module
Copyright (C) 2014-2021 Nuclex Development Labs

This library is free software; you can redistribute it and/or
modify it under the terms of the IBM Common Public License as
published by the IBM Corporation; either version 1.0 of the
License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
IBM Common Public License for more details.

You should have received a copy of the IBM Common Public
License along with this library
*/
#pragma endregion // CPL License

#include <CoreMinimal.h>
#include <ProceduralMeshComponent.h>

#include "ResizableDialogMeshComponent.generated.h"

// --------------------------------------------------------------------------------------------- //

/// Manages a mesh-based dialog box (for 3D UI) that can be dynamically resized
UCLASS(ClassGroup=(Custom), meta=(BlueprintSpawnableComponent))
class NUCLEX_API UResizableDialogMeshComponent : public UProceduralMeshComponent {

  GENERATED_BODY()

  /// Initializes a new resizable dialog mesh to its default settings
  /// @param  objectInitializer  Some Unreal Engine initialization crutch
  UResizableDialogMeshComponent(const FObjectInitializer &objectInitializer);

  //
  // UResizableDialogMeshComponent implementation
  //

  /// Returns the current size of the client area in the dialog box
  /// @returns The current client area size
  public: UFUNCTION(BlueprintCallable)
  FVector2D GetDialogBoxSize() const;

  /// Changes the size of the dialog box to fit the specified client area size
  /// @param  newSize  New size the client area of the dialog box will have (in world units)
  public: UFUNCTION(BlueprintCallable)
  void SetDialogBoxSize(const FVector2D &newSize);

  //
  // Internal implementation
  //

  /// Called when the game starts or when the actor is spawned into a running game
  protected: virtual void BeginPlay() override;

  /// Called when the game ends or when the actor is deleted from the running game
  /// @param  endPlayReason  Reason why the component is not in the game anymore
  protected: virtual void EndPlay(const EEndPlayReason::Type endPlayReason) override;

  /// Copies the vertices from the template mesh into our internal buffer
  private: void copyVerticesFromStaticMeshTemplate();

  /// Creates a backup of the original vertices to avoid floating point drift
  private: void backupOriginalVertices();

  /// Calculates the inner bounds, center and current client area size of the dialog box
  private: void calculateMeshMetrics();

  /// Forces the procedural mesh to update its vertex buffer from the vertex array
  private: void forceVertexBufferUpdate();

  /// Template mesh that will be used as the dialog box
  public: UPROPERTY(EditAnywhere, BlueprintReadWrite)
  UStaticMesh *MeshTemplate;

/* The flat axis is X and X shall be the flat axis.
  /// Axis along which the mesh template is flat
  public: UPROPERTY(EditAnywhere, BlueprintReadWrite)
  TEnumAsByte<EAxis::Type> MeshTemplateFlatAxis;
*/

  /// Original procedural mesh vertices for each section (submesh)
  private: TArray<TArray<FProcMeshVertex>> originalVertices;

  /// How far from the center the innermost vertices in each quadrant are
  private: FBox2D innerBounds;
  /// Center of the dialog box outer bounds
  private: FVector2D center;
  /// Current size of the usable client area
  private: FVector2D clientAreaSize;

  /// Used to temporarily store the vertex positions for forceVertexBufferUpdate()
  private: mutable TArray<FVector> vertices;
  /// Used to temporarily store the vertex normals for forceVertexBufferUpdate()
  private: mutable TArray<FVector> normals;
  /// Used to temporarily store the vertex UV coordinates for forceVertexBufferUpdate()
  private: mutable TArray<FVector2D> uvs;
  /// Used to temporarily store the vertex colors for forceVertexBufferUpdate()
  private: mutable TArray<FLinearColor> colors;
  /// Used to temporarily store the vertex tangents for forceVertexBufferUpdate()
  private: mutable TArray<FProcMeshTangent> tangents;

};

// --------------------------------------------------------------------------------------------- //