Added history — though still need to be checked thoroughly

Sources/Engine/Board.swift

@@ -5,6 +5,7 @@ enum Event {
 protocol EventDelegate {
 	func notify(_ event: Event)
 	func movePiece(_ piece: Piece, to dst: Square.Position) throws
+	func addPieceToTarget(_ piece: Piece, target: Square.Position)
 }
 public class Board: CustomStringConvertible, EventDelegate {
 	public typealias Grid = [[Square]]
@@ -24,6 +25,13 @@ public class Board: CustomStringConvertible, EventDelegate {
 
 	}
 
+	internal func addPieceToTarget(_ piece: Piece, target: Square.Position) {
+		guard var square = self[target] else {
+			return
+		}
+		square.targetted.insert(piece)
+	}
+
 	public private(set) var halfMoveClock: UInt8 = 0
 
 	public var fullMoveClock: UInt8 {
@@ -35,10 +43,16 @@ public class Board: CustomStringConvertible, EventDelegate {
 		.Black: [],
 	]
 
+	public internal(set) var history = History()
+
 	public private(set) var turn: Color = .White
 
 	func movePiece(_ piece: Piece, to dst: Square.Position) throws {
 		let from = piece.position
+		history.add(
+			.pieceMove(
+				from: squares[from.index!],
+				to: squares[dst.index!]))
 		piece.position = dst
 		squares[dst.index!].piece = piece
 		squares[from.index!].piece = nil
@@ -230,6 +244,9 @@ public class Board: CustomStringConvertible, EventDelegate {
 		#warning("Handle better.")
 		do {
 			try setBoard()
+			for square in squares where square.piece != nil {
+				square.piece?.getLegalPosition()
+			}
 		} catch Fen.FenError.NotAppropriateLength(let n, let column) {
 			fatalError("Not appropriate length: \(n) on \(column)")
 		} catch {