final class Pawn: Piece {
	private var sign: Int8 {
		color == .Black ? -1 : 1
	}
	override var pseudoLegalPositions: [Square.Position] {
		return [
			position + (1 * sign, 0),
			position + (2 * sign, 0),
			position + (1 * sign, 1),
			position + (1 * sign, -1),
		].filter { $0.index != nil }
	}

	override var unicodeRepresentation: String {
		color == .Black ? "♟" : "♙"
	}

	override func isLegal(on pos: Square.Position) -> Bool {
		#warning("Handle en-passant")
		if pos == position + (2 * sign, 0) && halfMoveCount > 0 {
			return false
		}
		if (pos == position + (1 * sign, 0) || pos == position + (2 * sign, 0))
			&& delegate?.getSquareInfo(on: pos)?.piece != nil
		{
			return false
		}
		guard super.isLegal(on: pos) else {
			return false
		}
		if (pos == position + (1 * sign, 1) || pos == position + (1 * sign, -1))
			&& delegate?.getSquareInfo(on: pos)?.piece == nil
		{
			return false
		}

		return true
	}

	init(with color: Color, on position: Square.Position) {
		super.init(kind: .Pawn, on: position, with: color)
	}
}