/// <summary>
/// Initializes new Piece by given color and type as:<br/>
/// "wp" => White Pawn<br/>
/// "br" => Black Rook<br/>
/// See: piece.ToString()<br/>
/// </summary>
public Piece(string piece)
{
if (!Regexes.regexPiece.IsMatch(piece))
{
throw new ChessArgumentException(null, "Piece should match pattern: " + Regexes.PiecePattern);
}
Color = PieceColor.FromChar(piece[0]);
Type = PieceType.FromChar(piece[1]);
}
internal static (bool succeeded, ChessException?exception) TryLoad(string fen, out FenBoardBuilder?builder)
{
builder = null;
var matches = Regexes.regexFen.Matches(fen);
if (matches.Count == 0)
{
return(false, new ChessArgumentException(null, "FEN board string should match pattern: " + Regexes.FenPattern));
}
builder = new FenBoardBuilder();
foreach (var group in matches[0].Groups.Values)
{
switch (group.Name)
{
case "1":
// Set pieces to given positions
int x = 0, y = 7;
for (int i = 0; i < group.Length; i++)
{
if (group.Value[i] == '/')
{
y--;
x = 0;
continue;
}
if (x < 8)
{
if (char.IsLetter(group.Value[i]))
{
builder.pieces[y, x] = new Piece(group.Value[i]);
x++;
}
else if (char.IsDigit(group.Value[i]))
{
x += int.Parse(group.Value[i].ToString());
}
}
}
break;
case "3":
builder.Turn = PieceColor.FromChar(group.Value[0]);
break;
case "4":
if (group.Value != "-")
{
if (group.Value.Contains('K'))
{
builder.CastleWK = true;
}
if (group.Value.Contains('Q'))
{
builder.CastleWQ = true;
}
if (group.Value.Contains('k'))
{
builder.CastleBK = true;
}
if (group.Value.Contains('q'))
{
builder.CastleBQ = true;
}
}
break;
case "5":
if (group.Value == "-")
{
builder.EnPassant = new();
}
else
{
builder.EnPassant = new Position(group.Value);
}
break;
case "6":
(builder.HalfMoves, builder.FullMoves) = group.Value.Split(' ').Select(s => int.Parse(s)).ToArray();
break;
}
}
var wcap = new List <Piece>();
var bcap = new List <Piece>();
var fpieces = builder.pieces.Cast <Piece>().Where(p => p is not null);
// Calculating missing pieces on according begin pieces in fen
// Math.Clamp() for get max/min taken figures (2 queens possible)
wcap.AddRange(Enumerable.Range(0, Math.Clamp(8 - fpieces.Where(p => p.Type == PieceType.Pawn && p.Color == PieceColor.White).Count(), 0, 8)).Select(_ => new Piece(PieceColor.White, PieceType.Pawn)));
wcap.AddRange(Enumerable.Range(0, Math.Clamp(2 - fpieces.Where(p => p.Type == PieceType.Rook && p.Color == PieceColor.White).Count(), 0, 2)).Select(_ => new Piece(PieceColor.White, PieceType.Rook)));
wcap.AddRange(Enumerable.Range(0, Math.Clamp(2 - fpieces.Where(p => p.Type == PieceType.Bishop && p.Color == PieceColor.White).Count(), 0, 2)).Select(_ => new Piece(PieceColor.White, PieceType.Bishop)));
wcap.AddRange(Enumerable.Range(0, Math.Clamp(2 - fpieces.Where(p => p.Type == PieceType.Knight && p.Color == PieceColor.White).Count(), 0, 2)).Select(_ => new Piece(PieceColor.White, PieceType.Knight)));
wcap.AddRange(Enumerable.Range(0, Math.Clamp(1 - fpieces.Where(p => p.Type == PieceType.Queen && p.Color == PieceColor.White).Count(), 0, 1)).Select(_ => new Piece(PieceColor.White, PieceType.Queen)));
bcap.AddRange(Enumerable.Range(0, Math.Clamp(8 - fpieces.Where(p => p.Type == PieceType.Pawn && p.Color == PieceColor.Black).Count(), 0, 8)).Select(_ => new Piece(PieceColor.Black, PieceType.Pawn)));
bcap.AddRange(Enumerable.Range(0, Math.Clamp(2 - fpieces.Where(p => p.Type == PieceType.Rook && p.Color == PieceColor.Black).Count(), 0, 2)).Select(_ => new Piece(PieceColor.Black, PieceType.Rook)));
bcap.AddRange(Enumerable.Range(0, Math.Clamp(2 - fpieces.Where(p => p.Type == PieceType.Bishop && p.Color == PieceColor.Black).Count(), 0, 2)).Select(_ => new Piece(PieceColor.Black, PieceType.Bishop)));
bcap.AddRange(Enumerable.Range(0, Math.Clamp(2 - fpieces.Where(p => p.Type == PieceType.Knight && p.Color == PieceColor.Black).Count(), 0, 2)).Select(_ => new Piece(PieceColor.Black, PieceType.Knight)));
bcap.AddRange(Enumerable.Range(0, Math.Clamp(1 - fpieces.Where(p => p.Type == PieceType.Queen && p.Color == PieceColor.Black).Count(), 0, 1)).Select(_ => new Piece(PieceColor.Black, PieceType.Queen)));
builder.WhiteCaptured = wcap.ToArray();
builder.BlackCaptured = bcap.ToArray();
return(true, null);
}
