--- /dev/null
+class MagneticRules extends ChessRules
+{
+ static get HasEnpassant() { return false; }
+
+ getPotentialMovesFrom([x,y])
+ {
+ let standardMoves = super.getPotentialMovesFrom([x,y]);
+ let moves = [];
+ standardMoves.forEach(m => {
+ let newMove_s = this.applyMagneticLaws(m);
+ if (newMove_s.length == 1)
+ moves.push(newMove_s[0]);
+ else //promotion
+ moves = moves.concat(newMove_s);
+ });
+ return moves;
+ }
+
+ // Complete a move with magnetic actions
+ // TODO: job is done multiple times for (normal) promotions.
+ applyMagneticLaws(move)
+ {
+ if (move.appear[0].p == V.KING && move.appear.length==1)
+ return [move]; //kings are not charged
+ const aIdx = (move.appear[0].p != V.KING ? 0 : 1); //if castling, rook is charged
+ const [x,y] = [move.appear[aIdx].x, move.appear[aIdx].y];
+ const color = this.turn;
+ const lastRank = (color=="w" ? 0 : 7);
+ const standardMove = JSON.parse(JSON.stringify(move));
+ this.play(standardMove);
+ for (let step of [[-1,0],[1,0],[0,-1],[0,1]])
+ {
+ let [i,j] = [x+step[0],y+step[1]];
+ while (V.OnBoard(i,j))
+ {
+ if (this.board[i][j] != V.EMPTY)
+ {
+ // Found something. Same color or not?
+ if (this.getColor(i,j) != color)
+ {
+ // Attraction
+ if ((Math.abs(i-x)>=2 || Math.abs(j-y)>=2) && this.getPiece(i,j) != V.KING)
+ {
+ move.vanish.push(
+ new PiPo({
+ p:this.getPiece(i,j),
+ c:this.getColor(i,j),
+ x:i,
+ y:j
+ })
+ );
+ move.appear.push(
+ new PiPo({
+ p:this.getPiece(i,j),
+ c:this.getColor(i,j),
+ x:x+step[0],
+ y:y+step[1]
+ })
+ );
+ }
+ }
+ else
+ {
+ // Repulsion
+ if (this.getPiece(i,j) != V.KING)
+ {
+ // Push it until we meet an obstacle or edge of the board
+ let [ii,jj] = [i+step[0],j+step[1]];
+ while (V.OnBoard(ii,jj))
+ {
+ if (this.board[ii][jj] != V.EMPTY)
+ break;
+ ii += step[0];
+ jj += step[1];
+ }
+ ii -= step[0];
+ jj -= step[1];
+ if (Math.abs(ii-i)>=1 || Math.abs(jj-j)>=1)
+ {
+ move.vanish.push(
+ new PiPo({
+ p:this.getPiece(i,j),
+ c:this.getColor(i,j),
+ x:i,
+ y:j
+ })
+ );
+ move.appear.push(
+ new PiPo({
+ p:this.getPiece(i,j),
+ c:this.getColor(i,j),
+ x:ii,
+ y:jj
+ })
+ );
+ }
+ }
+ }
+ break;
+ }
+ i += step[0];
+ j += step[1];
+ }
+ }
+ this.undo(standardMove);
+ let moves = [];
+ // Scan move for pawn (max 1) on 8th rank
+ for (let i=1; i<move.appear.length; i++)
+ {
+ if (move.appear[i].p==V.PAWN && move.appear[i].c==color
+ && move.appear[i].x==lastRank)
+ {
+ move.appear[i].p = V.ROOK;
+ moves.push(move);
+ for (let piece of [V.KNIGHT, V.BISHOP, V.QUEEN])
+ {
+ let cmove = JSON.parse(JSON.stringify(move));
+ cmove.appear[i].p = piece;
+ moves.push(cmove);
+ }
+ // Swap appear[i] and appear[0] for moves presentation (TODO: this is awkward)
+ moves.forEach(m => {
+ let tmp = m.appear[0];
+ m.appear[0] = m.appear[i];
+ m.appear[i] = tmp;
+ });
+ break;
+ }
+ }
+ if (moves.length == 0) //no pawn on 8th rank
+ moves.push(move);
+ return moves;
+ }
+
+ atLeastOneMove()
+ {
+ if (this.kingPos[this.turn][0] < 0)
+ return false;
+ return true; //TODO: is it right?
+ }
+
+ underCheck(color)
+ {
+ return false; //there is no check
+ }
+
+ getCheckSquares(move)
+ {
+ return [];
+ }
+
+ updateVariables(move)
+ {
+ super.updateVariables(move);
+ const c = move.vanish[0].c;
+ if (move.vanish.length >= 2 && move.vanish[1].p == V.KING)
+ {
+ // We took opponent king !
+ const oppCol = V.GetOppCol(c);
+ this.kingPos[oppCol] = [-1,-1];
+ this.castleFlags[oppCol] = [false,false];
+ }
+ // Did we magnetically move our (init) rooks or opponents' ones ?
+ const firstRank = (c == "w" ? 7 : 0);
+ const oppFirstRank = 7 - firstRank;
+ const oppCol = V.GetOppCol(c);
+ move.vanish.forEach(psq => {
+ if (psq.x == firstRank && this.INIT_COL_ROOK[c].includes(psq.y))
+ this.castleFlags[c][psq.y==this.INIT_COL_ROOK[c][0] ? 0 : 1] = false;
+ else if (psq.x == oppFirstRank && this.INIT_COL_ROOK[oppCol].includes(psq.y))
+ this.castleFlags[oppCol][psq.y==this.INIT_COL_ROOK[oppCol][0] ? 0 : 1] = false;
+ });
+ }
+
+ unupdateVariables(move)
+ {
+ super.unupdateVariables(move);
+ const c = move.vanish[0].c;
+ const oppCol = V.GetOppCol(c);
+ if (this.kingPos[oppCol][0] < 0)
+ {
+ // Last move took opponent's king
+ for (let psq of move.vanish)
+ {
+ if (psq.p == 'k')
+ {
+ this.kingPos[oppCol] = [psq.x, psq.y];
+ break;
+ }
+ }
+ }
+ }
+
+ checkGameEnd()
+ {
+ // No valid move: our king disappeared
+ return this.turn == "w" ? "0-1" : "1-0";
+ }
+
+ static get THRESHOLD_MATE()
+ {
+ return 500; //checkmates evals may be slightly below 1000
+ }
+}
projects / vchess.git / blobdiff