private Location GetPawnSourceLocation(Piece pawn, Location destinationLocation, string fromLocationHint)
{
//Check if the space was occupied
var previousPiece = GetPiece(destinationLocation);
if (previousPiece != null)
{
//It was a capture check the diagonals
//TODO: Validate that both locations do not contain a valid pawn
var leftLocation = Location.FromOffset(destinationLocation, -1, pawn.Color == PieceColor.White ? -1 : 1);
if (leftLocation != null && pawn.Equals(GetPiece(leftLocation)) && leftLocation.MatchesHint(fromLocationHint))
{
return(leftLocation);
}
var rightLocation = Location.FromOffset(destinationLocation, 1, pawn.Color == PieceColor.White ? -1 : 1);
if (rightLocation != null && pawn.Equals(GetPiece(rightLocation)) && rightLocation.MatchesHint(fromLocationHint))
{
return(rightLocation);
}
}
else
{
//Not a capture look for a pawn in the same file
var oneBackLocation = Location.FromOffset(destinationLocation, 0, pawn.Color == PieceColor.White ? -1 : 1);
if (pawn.Equals(GetPiece(oneBackLocation)))
{
return(oneBackLocation);
}
//Check if the pawn moved two spaces on its first move
if (pawn.Color == PieceColor.White && destinationLocation.Rank == 4)
{
var startingLocation = Location.FromOffset(destinationLocation, 0, -2);
if (pawn.Equals(GetPiece(startingLocation)))
{
return(startingLocation);
}
}
else if (pawn.Color == PieceColor.Black && destinationLocation.Rank == 5)
{
var startingLocation = Location.FromOffset(destinationLocation, 0, 2);
if (pawn.Equals(GetPiece(startingLocation)))
{
return(startingLocation);
}
}
}
return(null);
}
private Location GetKingSourceLocation(Piece king, Location destinationLocation)
{
var locations = new[]
{
Location.FromOffset(destinationLocation, 0, 1),
Location.FromOffset(destinationLocation, 1, 1),
Location.FromOffset(destinationLocation, 1, 0),
Location.FromOffset(destinationLocation, 1, -1),
Location.FromOffset(destinationLocation, 0, -1),
Location.FromOffset(destinationLocation, -1, -1),
Location.FromOffset(destinationLocation, -1, 0),
Location.FromOffset(destinationLocation, -1, 1)
};
return(locations.FirstOrDefault(location => king.Equals(GetPiece(location))));
}
private Location GetKnightSourceLocation(Piece knight, Location destinationLocation, string fromLocationHint)
{
var location = Location.FromOffset(destinationLocation, 2, 1);
if (location != null && knight.Equals(GetPiece(location)) && location.MatchesHint(fromLocationHint))
{
return(location);
}
location = Location.FromOffset(destinationLocation, 2, -1);
if (location != null && knight.Equals(GetPiece(location)) && location.MatchesHint(fromLocationHint))
{
return(location);
}
location = Location.FromOffset(destinationLocation, 1, -2);
if (location != null && knight.Equals(GetPiece(location)) && location.MatchesHint(fromLocationHint))
{
return(location);
}
location = Location.FromOffset(destinationLocation, -1, -2);
if (location != null && knight.Equals(GetPiece(location)) && location.MatchesHint(fromLocationHint))
{
return(location);
}
location = Location.FromOffset(destinationLocation, -2, -1);
if (location != null && knight.Equals(GetPiece(location)) && location.MatchesHint(fromLocationHint))
{
return(location);
}
location = Location.FromOffset(destinationLocation, -2, 1);
if (location != null && knight.Equals(GetPiece(location)) && location.MatchesHint(fromLocationHint))
{
return(location);
}
location = Location.FromOffset(destinationLocation, -1, 2);
if (location != null && knight.Equals(GetPiece(location)) && location.MatchesHint(fromLocationHint))
{
return(location);
}
location = Location.FromOffset(destinationLocation, 1, 2);
if (location != null && knight.Equals(GetPiece(location)) && location.MatchesHint(fromLocationHint))
{
return(location);
}
return(null);
}
private Location GetQueenSourceLocation(Piece queen, Location destinationLocation, string fromLocationHint)
{
return
(FindSourceLocationForPieceWithStrategy(queen, destinationLocation, l => Location.FromOffset(l, 0, 1), fromLocationHint) ??
FindSourceLocationForPieceWithStrategy(queen, destinationLocation, l => Location.FromOffset(l, 1, 1), fromLocationHint) ??
FindSourceLocationForPieceWithStrategy(queen, destinationLocation, l => Location.FromOffset(l, 1, 0), fromLocationHint) ??
FindSourceLocationForPieceWithStrategy(queen, destinationLocation, l => Location.FromOffset(l, 1, -1), fromLocationHint) ??
FindSourceLocationForPieceWithStrategy(queen, destinationLocation, l => Location.FromOffset(l, 0, -1), fromLocationHint) ??
FindSourceLocationForPieceWithStrategy(queen, destinationLocation, l => Location.FromOffset(l, -1, -1), fromLocationHint) ??
FindSourceLocationForPieceWithStrategy(queen, destinationLocation, l => Location.FromOffset(l, -1, 0), fromLocationHint) ??
FindSourceLocationForPieceWithStrategy(queen, destinationLocation, l => Location.FromOffset(l, -1, 1), fromLocationHint));
}
private Location GetBishopSourceLocation(Piece bishop, Location destinationLocation, string fromLocationHint)
{
return
(FindSourceLocationForPieceWithStrategy(bishop, destinationLocation, l => Location.FromOffset(l, -1, -1), fromLocationHint) ??
FindSourceLocationForPieceWithStrategy(bishop, destinationLocation, l => Location.FromOffset(l, -1, 1), fromLocationHint) ??
FindSourceLocationForPieceWithStrategy(bishop, destinationLocation, l => Location.FromOffset(l, 1, 1), fromLocationHint) ??
FindSourceLocationForPieceWithStrategy(bishop, destinationLocation, l => Location.FromOffset(l, 1, -1), fromLocationHint));
}