Utils.h

// Snake Game, Copyright LifeEXE. All Rights Reserved.
 
#pragma once
 
#include "CoreMinimal.h"
#include "Types.h"
 
namespace SnakeGame
{
class SNAKEGAME_API IPositionRandomizer
{
public:
    virtual bool generatePosition(const Dim& dim, const TArray<CellType>& cells, Position& position) const = 0;
    virtual ~IPositionRandomizer() = default;
};
 
class SNAKEGAME_API PositionRandomizer : public IPositionRandomizer
{
public:
    virtual bool generatePosition(const Dim& dim, const TArray<CellType>& cells, Position& position) const override
    {
        const uint32 startX = FMath::RandRange(1, dim.width - 2);
        const uint32 startY = FMath::RandRange(1, dim.height - 2);
        Position randomPosition = {startX, startY};
 
        do
        {
            const uint32 currentIndex = posToIndex(randomPosition, dim);
            if (cells[currentIndex] == CellType::Empty)
            {
                position = randomPosition;
                return true;
            }
 
            if (++randomPosition.x > dim.width - 2)
            {
                randomPosition.x = 1;
                if (++randomPosition.y > dim.height - 2)
                {
                    randomPosition.y = 1;
                }
            }
        } while (randomPosition.x != startX || randomPosition.y != startY);
 
        return false;
    }
 
private:
    FORCEINLINE Position indexToPos(uint32 index, const Dim& dim) const { return Position(index % dim.width, index / dim.width); }
    FORCEINLINE uint32 posToIndex(const Position& position, const Dim& dim) const { return position.x + position.y * dim.width; }
};
 
using IPositionRandomizerPtr = TSharedPtr<IPositionRandomizer>;
 
}  // namespace SnakeGame