67 lines
1.5 KiB
Swift
67 lines
1.5 KiB
Swift
final class Pawn: Piece {
|
|
var kind: Kind = .Pawn
|
|
weak var board: Board?
|
|
var color: Color
|
|
var position: Square.Position
|
|
var pseudoLegalPositions: [Square.Position] {
|
|
let sign: Int8 = color == .Black ? -1 : 1
|
|
let rank = Int8(position.rank)
|
|
let directions: [Square.Position] = [
|
|
.init(rank: rank + 1 * sign, file: position.file),
|
|
.init(rank: rank + 2 * sign, file: position.file),
|
|
.init(rank: rank + 1 * sign, file: position.file + 1),
|
|
.init(rank: rank + 1 * sign, file: position.file - 1)
|
|
]
|
|
// TODO: Handle en passant
|
|
return directions.filter { $0.index != nil }
|
|
}
|
|
var legalPositions: [Square.Position] {
|
|
pseudoLegalPositions.filter { isLegal(on: $0) }
|
|
}
|
|
|
|
var unicodeRepresentation: String {
|
|
color == .Black ? "♟" : "♙"
|
|
}
|
|
|
|
func move(to dst: Square.Position) -> Bool {
|
|
guard board != nil else {
|
|
return false
|
|
}
|
|
|
|
if !(legalPositions.contains { $0 == dst }) {
|
|
return false
|
|
}
|
|
|
|
if let board = board, var s = board[position], var d = board[dst] {
|
|
s.piece = self
|
|
d.piece = nil
|
|
}
|
|
|
|
position = dst
|
|
|
|
return true
|
|
}
|
|
|
|
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
|
|
return false
|
|
}
|
|
}
|
|
|
|
}
|
|
return true
|
|
}
|
|
|
|
init(
|
|
color: Color, on position: Square.Position
|
|
) {
|
|
self.color = color
|
|
self.position = position
|
|
}
|
|
}
|