private func getDirectionalMoves(
	from pos: Square.Position, with dir: [(Int8, Int8)]
) -> [Square.Position] {
	var squares = [Square.Position]()
	for i: (Int8, Int8) in dir {
		var currentSquare = pos + i
		while currentSquare.index != nil {
			squares.append(currentSquare)
			currentSquare += i
		}
	}
	return squares
}

protocol DiagonalMoves {
	func getDiagonalMoves(from pos: Square.Position) -> [Square.Position]
}

protocol Direction: CaseIterable {
	var values: (Int8, Int8) { get }
	static func isLegal(
		last: inout Square.Position?,
		current: Square.Position
	) -> Bool
}

public enum DiagonalDirection: Direction {
	case northWest
	case northEast
	case southEast
	case southWest

	public var values: (Int8, Int8) {
		return switch self {
		case .northWest: (1, -1)
		case .northEast: (1, 1)
		case .southEast: (-1, 1)
		case .southWest: (-1, -1)
		}
	}
	public static func isLegal(
		last: inout Square.Position?,
		current:
			Square.Position
	) -> Bool {
		var isPred = false
		for dir in DiagonalDirection.allCases {
			isPred = last == current - dir.values
			if isPred {
				last = current
				break
			}
		}

		return isPred
	}
}

extension DiagonalMoves {
	func getDiagonalMoves(from pos: Square.Position) -> [Square.Position] {
		getDirectionalMoves(
			from: pos,
			with: [
				DiagonalDirection.northWest.values,
				DiagonalDirection.northEast.values,
				DiagonalDirection.southEast.values,
				DiagonalDirection.southWest.values,
			])
	}
}

protocol LinearMoves {
	func getLinearMoves(from pos: Square.Position) -> [Square.Position]
}

public enum LinearDirection: Direction {
	case north
	case south
	case east
	case west

	public var values: (Int8, Int8) {
		return switch self {
		case .north: (1, 0)
		case .south: (-1, 0)
		case .east: (0, 1)
		case .west: (0, -1)
		}
	}

	public static func isLegal(
		last: inout Square.Position?, current: Square.Position
	) -> Bool {
		var isPred = false
		for dir in LinearDirection.allCases {
			isPred = last == current - dir.values
			if isPred {
				last = current
				break
			}
		}

		return isPred
	}
}

extension LinearMoves {
	func getLinearMoves(from pos: Square.Position) -> [Square.Position] {
		getDirectionalMoves(
			from: pos,
			with: [
				LinearDirection.north.values,
				LinearDirection.east.values,
				LinearDirection.south.values,
				LinearDirection.west.values,
			])
	}
}