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

	override var legalPositions: [Square.Position] {
		pseudoLegalPositions.filter { isLegal(on: $0) }
	}

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

	override func move(to dst: Square.Position) {
		if !(legalPositions.contains { $0 == dst }) {
			return
		}

		delegate?.movePiece(self, to: dst)

		// if let board = board, var s = board[position], var d = board[dst] {
		// 	s.piece = self
		// 	d.piece = nil
		// }

		// position = dst

		// return true
	}

	override func isLegal(on pos: Square.Position) -> Bool {
		// TODO: Handle "En-Passant"
		if let board = board, let s = board[pos] {
			if let p = s.piece {
				if p.color == color { return false }
				if p.kind == .King {
					// TODO: Notify board of check
					delegate?.notify(.kingInCheck(self))
					return false
				}
			}

		}
		return true
	}

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