Lots of changes

Sources/Engine/Board.swift

@@ -1,4 +1,12 @@
-public class Board: CustomStringConvertible {
+enum Event {
+	case kingInCheck(_ by: Piece)
+	case piecePinned(from: Piece, on: Piece)
+}
+protocol EventDelegate {
+	func notify(_ event: Event)
+	func movePiece(_ piece: Piece, to dst: Square.Position)
+}
+public class Board: CustomStringConvertible, EventDelegate {
 	public typealias Grid = [[Square]]
 
 	private enum UnicodeBar: String, CustomStringConvertible {
@@ -12,6 +20,18 @@ public class Board: CustomStringConvertible {
 		}
 	}
 
+	func notify(_ event: Event) {
+
+	}
+
+	func movePiece(_ piece: Piece, to dst: Square.Position) {
+
+	}
+
+	public func getSquareInfo(on pos: Square.Position) -> Square? {
+		self[pos]
+	}
+
 	private var squares = [Square]()
 	private var board: Grid {
 		var board = Grid()
@@ -37,7 +57,8 @@ public class Board: CustomStringConvertible {
 			let r = 8 - Int(rank)
 			if c == "/" {
 				if file != 9 {
-					throw Fen.FenError.NotAppropriateLength(n: file, column: index)
+					throw Fen.FenError.NotAppropriateLength(
+						n: file, column: index)
 				}
 				rank -= 1
 				file = 0
@@ -51,7 +72,7 @@ public class Board: CustomStringConvertible {
 				let f = file
 				for i in f..<(f + n) {
 					file += 1
-					b[8*r+Int(i)].piece = nil
+					b[8 * r + Int(i)].piece = nil
 				}
 				file -= 1
 			} else if c.isASCII {
@@ -60,19 +81,20 @@ public class Board: CustomStringConvertible {
 					let piece: Piece =
 						switch k {
 						case .Pawn:
-							Pawn(color: c, on: .init(rank: rank, file: file))
+							Pawn(with: c, on: .init(rank: rank, file: file))
 						case .Knight:
-							Knight(color: c, on: .init(rank: rank, file: file))
+							Knight(with: c, on: .init(rank: rank, file: file))
 						case .Bishop:
-							Bishop(color: c, on: .init(rank: rank, file: file))
+							Bishop(with: c, on: .init(rank: rank, file: file))
 						case .Rook:
-							Rook(color: c, on: .init(rank: rank, file: file))
+							Rook(with: c, on: .init(rank: rank, file: file))
 						case .Queen:
-							Queen(color: c, on: .init(rank: rank, file: file))
+							Queen(with: c, on: .init(rank: rank, file: file))
 						case .King:
-							King(color: c, on: .init(rank: rank, file: file))
+							King(with: c, on: .init(rank: rank, file: file))
 						}
-					b[8*r+Int(file)-1].piece = piece
+					piece.delegate = self
+					b[8 * r + Int(file) - 1].piece = piece
 				case .none:
 					throw Fen.FenError.InvalidCharacter(
 						c: String(c), column: index)
@@ -82,14 +104,16 @@ public class Board: CustomStringConvertible {
 			file += 1
 			index += 1
 		}
-		#if DEBUG 
-			print(b)	
-		#endif	
+		#if DEBUG
+			print(b)
+		#endif
 		squares = b
 	}
 
-	public required init(fen: Fen = 
-		.init(fen: "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1")
+	public required init(
+		fen: Fen =
+			.init(
+				fen: "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1")
 	) {
 		var rank: Int8 = 8
 		self.fen = fen
@@ -134,7 +158,7 @@ public class Board: CustomStringConvertible {
 		return boardString
 	}
 
-	public subscript(pos: Square.Position) -> Square? {
+	internal subscript(pos: Square.Position) -> Square? {
 		guard let i = pos.index else {
 			return nil
 		}
@@ -143,4 +167,4 @@ public class Board: CustomStringConvertible {
 		}
 		return squares[i]
 	}
-}
+}

Sources/Engine/Pieces/Bishop.swift

@@ -1,32 +1,26 @@
 final class Bishop: Piece, DiagonalMoves {
-	weak var board: Board?
-	var kind: Kind = .Bishop
 
-	var unicodeRepresentation: String {
+	override var unicodeRepresentation: String {
 		return color == .Black ? "♝" : "♗"
 	}
-	var color: Color
 
-	var position: Square.Position
-
-	var pseudoLegalPositions: [Square.Position] {
+	override var pseudoLegalPositions: [Square.Position] {
 		return getDiagonalMoves(from: position)
 	}
 
-	var legalPositions: [Square.Position] {
+	override var legalPositions: [Square.Position] {
 		return pseudoLegalPositions.filter { isLegal(on: $0) }
 	}
 
-	func move(to dst: Square.Position) -> Bool {
-		return false
+	override func move(to dst: Square.Position) {
 	}
 
-	func isLegal(on pos: Square.Position) -> Bool {
+	override func isLegal(on pos: Square.Position) -> Bool {
 		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
 				}
 			}
@@ -34,9 +28,8 @@ final class Bishop: Piece, DiagonalMoves {
 		return true
 	}
 
-	init(color: Color, on position: Square.Position) {
-		self.color = color
-		self.position = position
+	init(with color: Color, on position: Square.Position) {
+		super.init(kind: .Bishop, on: position, with: color)
 	}
 
 }

Sources/Engine/Pieces/King.swift

@@ -1,15 +1,10 @@
 final class King: Piece {
-	weak var board: Board?
-	var kind: Kind = .King
 
-	var unicodeRepresentation: String {
+	override var unicodeRepresentation: String {
 		return color == .Black ? "♛" : "♕"
 	}
-	var color: Color
 
-	var position: Square.Position
-
-	var pseudoLegalPositions: [Square.Position] {
+	override var pseudoLegalPositions: [Square.Position] {
 		[
 			position + (1, 0),
 			position + (1, 1),
@@ -18,19 +13,18 @@ final class King: Piece {
 			position + (-1, 0),
 			position + (-1, -1),
 			position + (0, -1),
-			position + (1, -1)
-		].filter {$0.index != nil}
+			position + (1, -1),
+		].filter { $0.index != nil }
 	}
 
-	var legalPositions: [Square.Position] {
+	override var legalPositions: [Square.Position] {
 		return pseudoLegalPositions.filter { isLegal(on: $0) }
 	}
 
-	func move(to dst: Square.Position) -> Bool {
-		return false
+	override func move(to dst: Square.Position) {
 	}
 
-	func isLegal(on pos: Square.Position) -> Bool {
+	override func isLegal(on pos: Square.Position) -> Bool {
 		if let board = board, let s = board[pos] {
 			if let p = s.piece {
 				if p.color == color { return false }
@@ -44,9 +38,8 @@ final class King: Piece {
 		return true
 	}
 
-	init(color: Color, on position: Square.Position) {
-		self.color = color
-		self.position = position
+	init(with color: Color, on position: Square.Position) {
+		super.init(kind: .King, on: position, with: color)
 	}
 
 }

Sources/Engine/Pieces/Knight.swift

@@ -1,15 +1,9 @@
 final class Knight: Piece {
-	weak var board: Board?
-	var kind: Kind = .Knight
-
-	var unicodeRepresentation: String {
+	override var unicodeRepresentation: String {
 		return color == .Black ? "♞" : "♘"
 	}
-	var color: Color
 
-	var position: Square.Position
-
-	var pseudoLegalPositions: [Square.Position] {
+	override var pseudoLegalPositions: [Square.Position] {
 		[
 			position + (2, 1),
 			position + (2, -1),
@@ -18,24 +12,24 @@ final class Knight: Piece {
 			position + (1, 2),
 			position + (1, -2),
 			position + (-1, 2),
-			position + (-1, -2)
+			position + (-1, -2),
 		].filter { $0.index != nil }
 	}
 
-	var legalPositions: [Square.Position] {
+	override var legalPositions: [Square.Position] {
 		return pseudoLegalPositions.filter { isLegal(on: $0) }
 	}
 
-	func move(to dst: Square.Position) -> Bool {
-		return false
+	override func move(to dst: Square.Position) {
 	}
 
-	func isLegal(on pos: Square.Position) -> Bool {
+	override func isLegal(on pos: Square.Position) -> Bool {
 		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
 				}
 			}
@@ -44,9 +38,8 @@ final class Knight: Piece {
 		return true
 	}
 
-	init(color: Color, on position: Square.Position) {
-		self.color = color
-		self.position = position
+	init(with color: Color, on position: Square.Position) {
+		super.init(kind: .Knight, on: position, with: color)
 	}
 
 }

Sources/Engine/Pieces/Pawn.swift

@@ -1,51 +1,47 @@
 final class Pawn: Piece {
-	var kind: Kind = .Pawn
-	weak var board: Board?
-	var color: Color
-	var position: Square.Position
-	var pseudoLegalPositions: [Square.Position] {
+	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)
+			position + (1 * sign, -1),
 		].filter { $0.index != nil }
 	}
-	var legalPositions: [Square.Position] {
+
+	override var legalPositions: [Square.Position] {
 		pseudoLegalPositions.filter { isLegal(on: $0) }
 	}
 
-	var unicodeRepresentation: String {
+	override var unicodeRepresentation: String {
 		color == .Black ? "♟" : "♙"
 	}
 
-	func move(to dst: Square.Position) -> Bool {
-		guard board != nil else {
-			return false
-		}
-
+	override func move(to dst: Square.Position) {
 		if !(legalPositions.contains { $0 == dst }) {
-			return false
+			return
 		}
 
-		if let board = board, var s = board[position], var d = board[dst] {
-			s.piece = self
-			d.piece = nil
-		}
+		delegate?.movePiece(self, to: dst)
 
-		position = dst
+		// if let board = board, var s = board[position], var d = board[dst] {
+		// 	s.piece = self
+		// 	d.piece = nil
+		// }
 
-		return true
+		// position = dst
+
+		// return true
 	}
 
-	func isLegal(on pos: Square.Position) -> Bool {
+	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
 				}
 			}
@@ -54,10 +50,7 @@ final class Pawn: Piece {
 		return true
 	}
 
-	init(
-		color: Color, on position: Square.Position
-	) {
-		self.color = color
-		self.position = position
+	init(with color: Color, on position: Square.Position) {
+		super.init(kind: .Pawn, on: position, with: color)
 	}
 }

Sources/Engine/Pieces/Piece.swift

@@ -1,4 +1,4 @@
-enum Kind: String, CaseIterable {
+public enum Kind: String, CaseIterable {
 	case Pawn, Knight, Bishop, Rook, Queen, King
 
 	var value: Int8 {
@@ -39,14 +39,28 @@ enum Kind: String, CaseIterable {
 	}
 }
 
-protocol Piece {
-	var board: Board? { get }
-	var color: Color { get }
-	var unicodeRepresentation: String { get }
-	var kind: Kind { get }
-	var position: Square.Position { get }
-	var pseudoLegalPositions: [Square.Position] { get }
-	var legalPositions: [Square.Position] { get }
-	func move(to dst: Square.Position) -> Bool
-	func isLegal(on pos: Square.Position) -> Bool
+public class Piece {
+	#warning("TODO: TO be removed, handle everything through the delegate")
+	internal weak var board: Board?
+	public internal(set) var color: Color
+	public var unicodeRepresentation: String {
+		return ""
+	}
+	public internal(set) var kind: Kind
+	public internal(set) var position: Square.Position
+	internal var pseudoLegalPositions: [Square.Position] {
+		return []
+	}
+	internal var legalPositions: [Square.Position] {
+		return []
+	}
+	internal var delegate: EventDelegate?
+	internal func move(to dst: Square.Position) {}
+	internal func isLegal(on pos: Square.Position) -> Bool { false }
+
+	internal init(kind: Kind, on pos: Square.Position, with col: Color) {
+		self.kind = kind
+		self.position = pos
+		self.color = col
+	}
 }

Sources/Engine/Pieces/Queen.swift

@@ -1,33 +1,27 @@
 final class Queen: Piece, LinearMoves, DiagonalMoves {
-	weak var board: Board?
-	var kind: Kind = .Queen
-
-	var unicodeRepresentation: String {
+	override var unicodeRepresentation: String {
 		return color == .Black ? "♛" : "♕"
 	}
-	var color: Color
 
-	var position: Square.Position
-
-	var pseudoLegalPositions: [Square.Position] {
+	override var pseudoLegalPositions: [Square.Position] {
 		return getDiagonalMoves(from: position) + getLinearMoves(from: position)
 	}
 
-	var legalPositions: [Square.Position] {
+	override var legalPositions: [Square.Position] {
 		return pseudoLegalPositions.filter { isLegal(on: $0) }
 	}
 
-	func move(to dst: Square.Position) -> Bool {
-		
-		return false
+	override func move(to dst: Square.Position) {
+
 	}
 
-	func isLegal(on pos: Square.Position) -> Bool {
+	override func isLegal(on pos: Square.Position) -> Bool {
 		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
 				}
 			}
@@ -36,9 +30,8 @@ final class Queen: Piece, LinearMoves, DiagonalMoves {
 		return true
 	}
 
-	init(color: Color, on position: Square.Position) {
-		self.color = color
-		self.position = position
+	init(with color: Color, on position: Square.Position) {
+		super.init(kind: .Queen, on: position, with: color)
 	}
 
 }

Sources/Engine/Pieces/Rook.swift

@@ -1,32 +1,27 @@
 final class Rook: Piece, LinearMoves {
-	weak var board: Board?
-	var kind: Kind = .Rook
 
-	var unicodeRepresentation: String {
+	override var unicodeRepresentation: String {
 		return color == .Black ? "♜" : "♖"
 	}
-	var color: Color
 
-	var position: Square.Position
-
-	var pseudoLegalPositions: [Square.Position] {
+	override var pseudoLegalPositions: [Square.Position] {
 		return getLinearMoves(from: position)
 	}
 
-	var legalPositions: [Square.Position] {
+	override var legalPositions: [Square.Position] {
 		return pseudoLegalPositions.filter { isLegal(on: $0) }
 	}
 
-	func move(to dst: Square.Position) -> Bool {
-		return false
+	override func move(to dst: Square.Position) {
 	}
 
-	func isLegal(on pos: Square.Position) -> Bool {
+	override func isLegal(on pos: Square.Position) -> Bool {
 		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
 				}
 			}
@@ -35,8 +30,10 @@ final class Rook: Piece, LinearMoves {
 		return true
 	}
 
-	init(color: Color, on position: Square.Position) {
+	init(with color: Color, on position: Square.Position) {
+		super.init(kind: .Rook, on: position, with: color)
 		self.color = color
+		self.kind = .Rook
 		self.position = position
 	}
 

Sources/Engine/Square.swift

@@ -8,7 +8,34 @@ public struct Square: Equatable {
 			guard (rank > 0 && rank < 9) && (file > 0 && file < 9) else {
 				return nil
 			}
-			return Int(8*(8-rank)+file-1)
+			return Int(8 * (8 - rank) + file - 1)
+		}
+
+		public init(rank r: Int8, file f: Int8) {
+			rank = r
+			file = f
+		}
+
+		public enum File: String, CustomStringConvertible {
+			case a, b, c, d, e, f, g, h
+
+			public static subscript(_ f: Int8) -> Self? {
+				return switch f {
+				case 1: Self.a
+				case 2: Self.b
+				case 3: Self.c
+				case 4: Self.d
+				case 5: Self.e
+				case 6: Self.f
+				case 7: Self.g
+				case 8: Self.h
+				default: nil
+				}
+			}
+
+			public var description: String {
+				self.rawValue.uppercased()
+			}
 		}
 
 		public static func == (lhs: Position, rhs: Position) -> Bool {
@@ -34,7 +61,7 @@ public struct Square: Equatable {
 
 	public let position: Position
 	public let index: Int
-	var piece: Piece? = nil
+	public internal(set) var piece: Piece? = nil
 	public let color: Color
 
 	public static func == (lhs: Square, rhs: Square) -> Bool {