/// <summary>
/// Builds left part of word before anchor
/// </summary>
/// <param name="partialWord">Word preceding anchor. Might already be on the board or placed from previous LeftPart calls</param>
/// <param name="limit">Limit of tiles we can place before anchor</param>
/// <param name="anchor">Anchor from which to build left and right part</param>
/// <param name="boardArray">Board array to work with (untransposed or transposed)</param>
/// <param name="validCrossChecks">A list of crosschecks which say what tiles can be played in each board tile</param>
/// <param name="validMovesList">A list of valid moves which is continuously updated</param>
/// <param name="boardIsHorizontal">Board is untransposed or transposed</param>
/// <param name="boardBeforeMove">Board before any moves were generated</param>
public void LeftPart(string partialWord, int limit, int[] anchor, BoardTile[,] boardArray, Dictionary <BoardTile, List <CharTile> > validCrossChecks,
HashSet <GeneratedMove> validMovesList, bool boardIsHorizontal, BoardTile[,] boardBeforeMove)
{
//Tries to build all right parts for given left part
ExtendRight(partialWord, anchor, boardArray, validCrossChecks, validMovesList, boardIsHorizontal, boardBeforeMove);
if (limit > 0)
{
//Gets a list of letters that can follow the current left part and can be placed to the left of the anchor
HashSet <string> labelsOfDawgEdges = new HashSet <string>(new DawgEdgeEqualityComparer());
var wordsWithCommonPreffix = Dawg.MatchPrefix(partialWord);
foreach (var word in wordsWithCommonPreffix)
{
labelsOfDawgEdges.Add(word.Key.Substring(partialWord.Length));
}
foreach (var label in labelsOfDawgEdges)
{
if (label == "")
{
continue;
}
if (OriginalRackOfPlayer.CheckIfWordIsPlayable(partialWord + label[0]) &&
((!validCrossChecks.Any(c => c.Key == boardArray[anchor[0], anchor[1] - 1]) ||
validCrossChecks.Any(c => c.Key == boardArray[anchor[0], anchor[1] - 1] &&
c.Value.Any(x => x.Letter == label[0])))))
{
CharTile tileToWorkWith = null;
if (RackOfCurrentPlayer.CheckIfTileIsInRack(label[0], false))
{
tileToWorkWith = Dictionary.CharTiles.Where(c => c.Letter == label[0] && c.Score != 0).FirstOrDefault();
}
else
{
tileToWorkWith = Dictionary.CharTiles.Where(c => c.Letter == '*').FirstOrDefault();
}
//Rebuilds left part with new tiles
for (int i = 0; i < partialWord.Length; i++)
{
boardArray[anchor[0], anchor[1] - 1 - i].CharTile = null;
}
for (int i = 0; i < partialWord.Length; i++)
{
var tileToAdd = OriginalRackOfPlayer.GetTile(partialWord[i]);
boardArray[anchor[0], anchor[1] - partialWord.Length - 1 + i].CharTile = tileToAdd;
}
RackOfCurrentPlayer.SubstractFromRack(tileToWorkWith);
boardArray[anchor[0], anchor[1] - 1].CharTile = tileToWorkWith;
bool validPrefix = true;
//Checks if the newly formed left part's components are valid for the board
for (int i = 0; i < partialWord.Length; i++)
{
var boardTile = boardArray[anchor[0], anchor[1] - 1 - partialWord.Length + i];
if (!(!validCrossChecks.Any(c => c.Key == boardTile) ||
validCrossChecks.Any(c => c.Key == boardTile &&
c.Value.Any(x => x.Letter == partialWord[i]))))
{
validPrefix = false;
break;
}
}
//If they are valid, call LeftPart again, which will call ExtendRight for all possible right moves and eventually try a new left part
if (validPrefix)
{
LeftPart(partialWord + label[0], limit - 1, anchor, boardArray, validCrossChecks, validMovesList, boardIsHorizontal, boardBeforeMove);
}
RackOfCurrentPlayer.AddToRack(tileToWorkWith);
boardArray[anchor[0], anchor[1] - 1].CharTile = null;
//Resets the left part once done
for (int i = 0; i < partialWord.Length; i++)
{
boardArray[anchor[0], anchor[1] - partialWord.Length - 1 + i].CharTile = null;
}
}
}
}
}
/// <summary>
/// Builds all possible right parts for given anchor
/// </summary>
/// <param name="partialWord">Word preceding right part</param>
/// <param name="anchor">Tile from which to build up right part</param>
/// <param name="boardArray">Board to work with</param>
/// <param name="validCrossChecks">List of valid cross checks for all empty tiles</param>
/// <param name="validMovesList">List of valid moves that gets updated</param>
/// <param name="boardIsHorizontal">Board is untransposed or transposed</param>
/// <param name="boardBeforeMove">Board before any moves were generated</param>
/// <param name="tileExtendedWith">Tile that was used to extend the right part</param>
public void ExtendRight(string partialWord, int[] anchor, BoardTile[,] boardArray, Dictionary <BoardTile,
List <CharTile> > validCrossChecks, HashSet <GeneratedMove> validMovesList, bool boardIsHorizontal, BoardTile[,] boardBeforeMove,
CharTile tileExtendedWith = null)
{
//If no tile is present..
if (boardArray[anchor[0], anchor[1]].CharTile == null)
{
//If word up until current tile is valid..
if (Helper.CheckWordValidity(Dawg, partialWord))
{
//If the move (word, row and column indexes) has not been added already..
if (!Moves.Any(m => m.Word.Equals(partialWord)))
{
//Adds generated move to list of valid moves
Dictionary <BoardTile, CharTile> tilesUsed = new Dictionary <BoardTile, CharTile>();
//Adds tiles that were used in move
for (int i = 0; i < partialWord.Length; i++)
{
var letter = partialWord[i];
var boardTile = boardArray[anchor[0], anchor[1] - partialWord.Length + i];
if (boardTile.CharTile != null)
{
tilesUsed.Add(boardTile, boardTile.CharTile);
}
else
{
tilesUsed.Add(boardTile, tileExtendedWith);
}
}
validMovesList.Add(new GeneratedMove(boardIsHorizontal, anchor[1] - partialWord.Length, anchor[1] - 1, anchor, tilesUsed, boardBeforeMove, RackOfCurrentPlayer));
}
}
//GEts all letters that can follow current right part word
HashSet <string> labelsOfDawgEdges = new HashSet <string>(new DawgEdgeEqualityComparer());
var wordsWithCommonPreffix = Dawg.MatchPrefix(partialWord);
foreach (var word in wordsWithCommonPreffix)
{
labelsOfDawgEdges.Add(word.Key.Substring(partialWord.Length));
}
foreach (var label in labelsOfDawgEdges)
{
//If the valid letter is in our rack and can be played on the board tile, places it and extends right again
//with the newly filled board tile used as anchor if board limit is not reached
if (label == "")
{
continue;
}
if (RackOfCurrentPlayer.CheckIfTileIsInRack(label[0], true) &&
(!validCrossChecks.Any(c => c.Key == boardArray[anchor[0], anchor[1]]) ||
validCrossChecks.Any(c => c.Key == boardArray[anchor[0], anchor[1]] && c.Value.Any(x => x.Letter == label[0]))))
{
CharTile tileToWorkWith = null;
if (RackOfCurrentPlayer.CheckIfTileIsInRack(label[0], false))
{
tileToWorkWith = Dictionary.CharTiles.Where(c => c.Letter == label[0] && c.Score != 0).FirstOrDefault();
}
else
{
tileToWorkWith = Dictionary.CharTiles.Where(c => c.Letter == '*').FirstOrDefault();
}
RackOfCurrentPlayer.SubstractFromRack(tileToWorkWith);
boardArray[anchor[0], anchor[1]].CharTile = Dictionary.CharTiles.Where(c => c.Letter == label[0] && c.Score == tileToWorkWith.Score).FirstOrDefault();
if (anchor[1] < boardArray.GetLength(1) - 1)
{
ExtendRight(partialWord + label[0], new int[] { anchor[0], anchor[1] + 1 }, boardArray, validCrossChecks, validMovesList, boardIsHorizontal, boardBeforeMove, tileToWorkWith);
}
//Otherwise places the tile on the last empty square of the board, checks if its valid and doesn't attempt to extend anymore
else
{
var finalWord = partialWord + boardArray[anchor[0], anchor[1]].CharTile.Letter;
if (Helper.CheckWordValidity(Dawg, finalWord))
{
if (!Moves.Any(m => m.Word.Equals(finalWord)))
{
Dictionary <BoardTile, CharTile> tilesUsed = new Dictionary <BoardTile, CharTile>();
for (int i = 0; i < finalWord.Length; i++)
{
var letter = finalWord[i];
var boardTile = boardArray[anchor[0], anchor[1] - finalWord.Length + 1 + i];
if (boardTile.CharTile != null)
{
tilesUsed.Add(boardTile, boardTile.CharTile);
}
else
{
tilesUsed.Add(boardTile, tileToWorkWith);
}
}
validMovesList.Add(new GeneratedMove(boardIsHorizontal, anchor[1] - finalWord.Length + 1, anchor[1], anchor, tilesUsed, boardBeforeMove, RackOfCurrentPlayer));
}
}
}
RackOfCurrentPlayer.AddToRack(tileToWorkWith);
boardArray[anchor[0], anchor[1]].CharTile = null;
}
}
}
//Otherwise if the current tile is already taken and not empty, used letter from board tile to build to the right again
else
{
var tile = boardArray[anchor[0], anchor[1]].CharTile;
HashSet <string> labelsOfDawgEdges = new HashSet <string>(new DawgEdgeEqualityComparer());
var wordsWithCommonPreffix = Dawg.MatchPrefix(partialWord + tile.Letter);
foreach (var word in wordsWithCommonPreffix)
{
labelsOfDawgEdges.Add(word.Key.Substring((partialWord + tile.Letter).Length));
}
//Extends right if any letters can follow the current right part
if (labelsOfDawgEdges.Any() && anchor[1] < boardArray.GetLength(1) - 1)
{
ExtendRight(partialWord + tile.Letter, new int[] { anchor[0], anchor[1] + 1 }, boardArray, validCrossChecks, validMovesList, boardIsHorizontal, boardBeforeMove, tile);
}
}
}
/// <summary>
/// Builds and returns possible moves for the current board
/// The same algorithm is used for a untransposed(horizontal) and transposed (vertical) board.
/// This limits the problem to one dimension - with the given rack, anchors and cross checks,
/// build all possible words on this row.
/// </summary>
/// <param name="boardIsHorizontal"></param>
/// <param name="giveOneResult"></param>
/// <returns></returns>
public HashSet <GeneratedMove> GetValidMoves(bool boardIsHorizontal, bool giveOneResult = false)
{
var retriesPerAnchor = 2;
var boardArray = boardIsHorizontal ? BoardArray : TransposedBoardArray;
//Recreates board before any moves are generated
var boardBeforeMove = new BoardTile[boardArray.GetLength(0), boardArray.GetLength(1)];
for (int i = 0; i < boardArray.GetLength(0); i++)
{
for (int j = 0; j < boardArray.GetLength(1); j++)
{
boardBeforeMove[i, j] = new BoardTile
{
BoardLocationX = boardArray[i, j].BoardLocationX,
BoardLocationY = boardArray[i, j].BoardLocationY,
BoardTileType = boardArray[i, j].BoardTileType,
CharTile = boardArray[i, j].CharTile,
Board = boardArray[i, j].Board,
BoardID = boardArray[i, j].BoardID,
BoardTileTypeID = boardArray[i, j].BoardTileTypeID,
CharTileID = boardArray[i, j].CharTileID,
ID = boardArray[i, j].ID,
IsFilled = boardArray[i, j].IsFilled
};
}
}
var listOfValidAnchorCoordinates = boardIsHorizontal ? ListOfValidAnchorCoordinatesOnUntransposedBoard : ListOfValidAnchorCoordinatesOnTransposedBoard;
var validCrossChecks = boardIsHorizontal ? ValidUntransposedCrossChecks : ValidTransposedCrossChecks;
HashSet <GeneratedMove> validMovesList = new HashSet <GeneratedMove>(new GeneratedMoveEqualityComparer());
//Shuffles anchors to add unpredictability to move generation
listOfValidAnchorCoordinates.Shuffle();
var originalTimeLimit = TimeLimit;
var retriesForCurrentAnchor = retriesPerAnchor;
//Starts stopwatch. Move generation stops if time limit has been reached after a recursive call has returned to its original state.
Stopwatch.Start();
//listOfValidAnchorCoordinates = new List<int[]>();
//listOfValidAnchorCoordinates.Add(new int[] { 12, 7 });
//listOfValidAnchorCoordinates.Add(new int[] { 12, 8 });
//listOfValidAnchorCoordinates.Add(new int[] { 12, 9 });
//Tries to attach words to all anchors on the board
for (int i = 0; i < listOfValidAnchorCoordinates.Count; i++)
{
if (retriesForCurrentAnchor == 0)
{
retriesForCurrentAnchor = retriesPerAnchor;
continue;
}
var anchor = listOfValidAnchorCoordinates[i];
//Checks if any letter can be played in tile. If not, target next anchor
var crossCheckEntry = validCrossChecks.Where(c => c.Key == boardArray[anchor[0], anchor[1]]).FirstOrDefault().Value;
if (crossCheckEntry != null && crossCheckEntry.Count == 0)
{
continue;
}
var limit = 0;
var columnIndex = anchor[1];
var wordBeforeAnchor = "";
//Builds up word before anchor if it exists, otherwise builds a limit to tiles we can place before anchor
while (columnIndex > 0)
{
if (boardArray[anchor[0], columnIndex - 1].CharTile == null && !listOfValidAnchorCoordinates.Any(c => c[0] == anchor[0] && c[1] == columnIndex - 1))
{
limit++;
columnIndex--;
}
else if (boardArray[anchor[0], columnIndex - 1].CharTile != null)
{
while (columnIndex > 0 && boardArray[anchor[0], columnIndex - 1].CharTile != null)
{
wordBeforeAnchor = wordBeforeAnchor.Insert(0, boardArray[anchor[0], columnIndex - 1].CharTile.Letter.ToString());
columnIndex--;
}
break;
}
else if (boardArray[anchor[0], columnIndex - 1].CharTile == null)
{
break;
}
}
//If no letter can be placed before anchor, try to build right part after anchor
if (limit == 0)
{
ExtendRight(wordBeforeAnchor, anchor, boardArray, validCrossChecks, validMovesList, boardIsHorizontal, boardBeforeMove);
}
//Otherwise places a valid tile from rack
else if (wordBeforeAnchor.Length == 0)
{
foreach (var entry in Dictionary.CharTiles.Where(d => d.Score != 0))
{
if (RackOfCurrentPlayer.CheckIfTileIsInRack(entry.Letter, true) &&
(!validCrossChecks.Any(c => c.Key == boardArray[anchor[0], anchor[1]]) ||
validCrossChecks.Any(c => c.Key == boardArray[anchor[0], anchor[1]] &&
c.Value.Any(x => x.Letter == entry.Letter))) &&
anchor[1] < boardArray.GetLength(1) - 1)
{
var tile = RackOfCurrentPlayer.SubstractFromRack(entry.Letter);
boardArray[anchor[0], anchor[1]].CharTile = tile;
//Once a tile is placed to the left of anchor, LeftPart is called which firstly tries to build all possible right parts for that anchor
//Once the extension to the right is complete, goes back to try and build a new left part
LeftPart(tile.Letter.ToString(), limit, new int[] { anchor[0], anchor[1] + 1 }, boardArray, validCrossChecks, validMovesList, boardIsHorizontal, boardBeforeMove);
RackOfCurrentPlayer.AddToRack(tile);
boardArray[anchor[0], anchor[1]].CharTile = null;
if (Helper.CheckIfTimeLimitIsReached(Stopwatch, TimeLimit) && validMovesList.Count > 0)
{
Stopwatch.Reset();
return(validMovesList);
}
}
}
}
if (giveOneResult)
{
return(validMovesList);
}
//If timer is reached and no moves are found for anchor, increase time limit and try again for that anchor
//If there are still no moves after two retries, move to different anchor
if (Helper.CheckIfTimeLimitIsReached(Stopwatch, TimeLimit))
{
if (validMovesList.Count == 0)
{
if (retriesForCurrentAnchor != 0)
{
TimeLimit += 1;
retriesForCurrentAnchor--;
i--;
Stopwatch.Restart();
}
}
else
{
TimeLimit = originalTimeLimit;
Stopwatch.Reset();
return(validMovesList);
}
}
}
return(validMovesList);
}