About to finish completed Ultima rules
[vchess.git] / public / javascripts / variants / Ultima.js
index 18afe40..57f3e25 100644 (file)
@@ -50,16 +50,46 @@ class UltimaRules extends ChessRules
        //  - a "bishop" is a chameleon, capturing as its prey
        //  - a "queen" is a withdrawer, capturing by moving away from pieces
 
-       getPotentialMovesFrom([x,y])
+       // Is piece on square (x,y) immobilized?
+       isImmobilized([x,y])
        {
-               // Pre-check: is thing on this square immobilized?
-               // In this case add potential suicide as a move "taking the immobilizer"
+                                       // Final check: is this knight immobilized?
+                                       let foundImmobilizer = false;
+                                       let neutralized = false;
+                                       outerLoop:
+                                       for (let step of steps)
+                                       {
+                                               const [i2,j2] = [i+step[0],j+step[1]];
+                                               if (i2>=0 && i2<sizeX && j2>=0 && j2<sizeY
+                                                       && this.board[i2][j2] != V.EMPTY
+                                                       && this.getColor(i2,j2) == oppCol
+                                                       && this.getPiece(i2,j2) == V.IMMOBILIZER)
+                                               {
+                                                       foundImmobilizer = true;
+                                                       // Moving is possible only if this immobilizer is neutralized
+                                                       for (let step2 of steps)
+                                                       {
+                                                               const [i3,j3] = [i2+step2[0],j2+step2[1]];
+                                                               if (i3>=0 && i3<sizeX && j3>=0 && j3<sizeY
+                                                                       && this.board[i3][j3] != V.EMPTY && this.getColor(i3,j3) == color
+                                                                       && [V.BISHOP,V.IMMOBILIZER].includes(this.getPiece(i3,j3)))
+                                                               {
+                                                                       neutralized = true;
+                                                                       break outerLoop;
+                                                               }
+                                                       }
+                                               }
+                                       }
+                                       if (!foundImmobilizer || neutralized)
+                                               return false;
+               
                const piece = this.getPiece(x,y);
                const color = this.getColor(x,y);
                const oppCol = this.getOppCol(color);
                const V = VariantRules;
                const adjacentSteps = V.steps[V.ROOK].concat(V.steps[V.BISHOP]);
                const [sizeX,sizeY] = V.size;
+               outerLoop:
                for (let step of adjacentSteps)
                {
                        const [i,j] = [x+step[0],y+step[1]];
@@ -67,18 +97,33 @@ class UltimaRules extends ChessRules
                                && this.getColor(i,j) == oppCol)
                        {
                                const oppPiece = this.getPiece(i,j);
-                               if (oppPiece == V.IMMOBILIZER
-                                       || (oppPiece == V.BISHOP && piece == V.IMMOBILIZER))
+                               if (oppPiece == V.BISHOP && piece == V.IMMOBILIZER)
+                                       return [];
+                               if (oppPiece == V.IMMOBILIZER && ![V.BISHOP,V.IMMOBILIZER].includes(piece))
                                {
-                                       return [ new Move({
-                                               appear: [],
-                                               vanish: [{x:x,y:y,p:piece,c:color}],
-                                               start: {x:x,y:y},
-                                               end: {x:i,y:j}
-                                       }) ];
+                                       // Moving is impossible only if this immobilizer is not neutralized
+                                       for (let step2 of adjacentSteps)
+                                       {
+                                               const [i2,j2] = [i+step2[0],j+step2[1]];
+                                               if (i2>=0 && i2<sizeX && j2>=0 && j2<sizeY
+                                                       && this.board[i2][j2] != V.EMPTY && this.getColor(i2,j2) == color)
+                                               {
+                                                       const friendlyPiece = this.getPiece(i2,j2);
+                                                       if ([V.BISHOP,V.IMMOBILIZER].includes(friendlyPiece))
+                                                               break outerLoop;
+                                               }
+                                       }
+                                       return []; //immobilizer isn't neutralized
                                }
                        }
                }
+       }
+
+       getPotentialMovesFrom([x,y])
+       {
+               // Pre-check: is thing on this square immobilized?
+               if (this.isImmobilized([x,y]))
+                       return [];
                switch (this.getPiece(x,y))
                {
                        case VariantRules.IMMOBILIZER:
@@ -118,23 +163,58 @@ class UltimaRules extends ChessRules
                return moves;
        }
 
+       // Modify capturing moves among listed pawn moves
+       addPawnCaptures(moves, byChameleon)
+       {
+               const steps = VariantRules.steps[VariantRules.ROOK];
+               const [sizeX,sizeY] = VariantRules.size;
+               const color = this.turn;
+               const oppCol = this.getOppCol(color);
+               moves.forEach(m => {
+                       if (!!byChameleon && m.start.x!=m.end.x && m.start.y!=m.end.y)
+                               return; //chameleon not moving as pawn
+                       // Try capturing in every direction
+                       for (let step of steps)
+                       {
+                               const sq2 = [m.end.x+2*step[0],m.end.y+2*step[1]];
+                               if (sq2[0]>=0 && sq2[0]<sizeX && sq2[1]>=0 && sq2[1]<sizeY
+                                       && this.board[sq2[0]][sq2[1]] != VariantRules.EMPTY
+                                       && this.getColor(sq2[0],sq2[1]) == color)
+                               {
+                                       // Potential capture
+                                       const sq1 = [m.end.x+step[0],m.end.y+step[1]];
+                                       if (this.board[sq1[0]][sq1[1]] != VariantRules.EMPTY
+                                               && this.getColor(sq1[0],sq1[1]) == oppCol)
+                                       {
+                                               const piece1 = this.getPiece(sq1[0],sq1[1]);
+                                               if (!byChameleon || piece1 == VariantRules.PAWN)
+                                               {
+                                                       m.vanish.push(new PiPo({
+                                                               x:sq1[0],
+                                                               y:sq1[1],
+                                                               c:oppCol,
+                                                               p:piece1
+                                                       }));
+                                               }
+                                       }
+                               }
+                       }
+               });
+       }
+
        // "Pincher"
        getPotentialPawnMoves([x,y])
        {
                let moves = super.getPotentialRookMoves([x,y]);
-               // Add captures
-               moves.forEach(m => {
-                       if (m
-               });
+               this.addPawnCaptures(moves);
+               return moves;
        }
 
-       // Coordinator
-       getPotentialRookMoves(sq)
+       addRookCaptures(moves, byChameleon)
        {
-               const color = this.getColor(sq);
+               const color = this.turn;
                const oppCol = this.getOppCol(color);
                const kp = this.kingPos[color];
-               let moves = super.getPotentialQueenMoves(sq);
                moves.forEach(m => {
                        // Check piece-king rectangle (if any) corners for enemy pieces
                        if (m.end.x == kp[0] || m.end.y == kp[1])
@@ -145,27 +225,42 @@ class UltimaRules extends ChessRules
                        {
                                if (this.board[i][j] != VariantRules.EMPTY && this.getColor(i,j) == oppCol)
                                {
-                                       m.vanish.push( new PiPo({
-                                               x:i,
-                                               y:j,
-                                               p:this.getPiece(i,j),
-                                               c:oppCol
-                                       }) );
+                                       const piece = this.getPiece(i,j);
+                                       if (!byChameleon || piece == VariantRules.ROOK)
+                                       {
+                                               m.vanish.push( new PiPo({
+                                                       x:i,
+                                                       y:j,
+                                                       p:piece,
+                                                       c:oppCol
+                                               }) );
+                                       }
                                }
                        }
                });
+       }
+
+       // Coordinator
+       getPotentialRookMoves(sq)
+       {
+               let moves = super.getPotentialQueenMoves(sq);
+               this.addRookCaptures(moves);
                return moves;
        }
 
        // Long-leaper
-       getPotentialKnightMoves([x,y])
+       getKnightCaptures(startSquare, byChameleon)
        {
-               let moves = super.getPotentialQueenMoves(sq);
                // Look in every direction for captures
                const V = VariantRules;
                const steps = V.steps[V.ROOK].concat(V.steps[V.BISHOP]);
                const [sizeX,sizeY] = V.size;
-               const color = this.getColor(x,y);
+               const color = this.turn;
+               const oppCol = this.getOppCol(color);
+               let moves = [];
+               const [x,y] = [startSquare[0],startSquare[1]];
+               const piece = this.getPiece(x,y); //might be a chameleon!
+               outerLoop:
                for (let step of steps)
                {
                        let [i,j] = [x+step[0], y+step[1]];
@@ -174,44 +269,115 @@ class UltimaRules extends ChessRules
                                i += step[0];
                                j += step[1];
                        }
-                       if (i<0 && i>=sizeX || j<0 || j>=sizeY || this.getColor(i,j)==color)
+                       if (i<0 || i>=sizeX || j<0 || j>=sizeY || this.getColor(i,j)==color
+                               || (!!byChameleon && this.getPiece(i,j)!=V.KNIGHT))
+                       {
                                continue;
-                       // Found an enemy piece: potential capture (if empty space behind)
-                       // So, while we find enemy pieces + space in this direction, add captures!
-                       i += step[0];
-                       j += step[1];
-                       while ( ) //TODO: finish........
+                       }
+                       // last(thing), cur(thing) : stop if "cur" is our color, or beyond board limits,
+                       // or if "last" isn't empty and cur neither. Otherwise, if cur is empty then
+                       // add move until cur square; if cur is occupied then stop if !!byChameleon and
+                       // the square not occupied by a leaper.
+                       let last = [i,j];
+                       let cur = [i+step[0],j+step[1]];
+                       let vanished = [ new PiPo({x:x,y:y,c:color,p:piece}) ];
+                       while (cur[0]>=0 && cur[0]<sizeX && cur[1]>=0 && cur[1]<sizeY)
+                       {
+                               if (this.board[last[0]][last[1]] != V.EMPTY)
+                               {
+                                       const oppPiece = this.getPiece(last[0],last[1]);
+                                       if (!!byChameleon && oppPiece != V.KNIGHT)
+                                               continue outerLoop;
+                                       // Something to eat:
+                                       vanished.push( new PiPo({x:last[0],y:last[1],c:oppCol,p:oppPiece}) );
+                               }
+                               if (this.board[cur[0]][cur[1]] != V.EMPTY)
+                               {
+                                       if (this.getColor(cur[0],cur[1]) == color
+                                               || this.board[last[0]][last[1]] != V.EMPTY) //TODO: redundant test
+                                       {
+                                               continue outerLoop;
+                                       }
+                               }
+                               else
+                               {
+                                       moves.push(new Move({
+                                               appear: [ new PiPo({x:cur[0],y:cur[1],c:color,p:piece}) ],
+                                               vanish: JSON.parse(JSON.stringify(vanished)), //TODO: required?
+                                               start: {x:x,y:y},
+                                               end: {x:cur[0],y:cur[1]}
+                                       }));
+                               }
+                               last = [last[0]+step[0],last[1]+step[1]];
+                               cur = [cur[0]+step[0],cur[1]+step[1]];
+                       }
                }
                return moves;
        }
 
-       getPotentialBishopMoves(sq)
+       // Long-leaper
+       getPotentialKnightMoves(sq)
        {
-               return super.getPotentialQueenMoves(sq);
-               // TODO: add captures of coordinators,pinchers,withdrawers... by re-using code
+               return super.getPotentialQueenMoves(sq).concat(this.getKnightCaptures(sq));
        }
 
-       getPotentialQueenMoves([x,y])
+       getPotentialBishopMoves([x,y])
        {
-               let moves = super.getPotentialQueenMoves(sq);
+               let moves = super.getPotentialQueenMoves([x,y])
+                       .concat(this.getKnightCaptures([x,y],"asChameleon"));
+               // No "king capture" because king cannot remain under check
+               this.addPawnCaptures(moves, "asChameleon");
+               this.addRookCaptures(moves, "asChameleon");
+               this.addQueenCaptures(moves, "asChameleon");
+               // Post-processing: merge similar moves, concatenating vanish arrays
+               let mergedMoves = {};
+               const [sizeX,sizeY] = VariantRules.size;
+               moves.forEach(m => {
+                       const key = m.end.x + sizeX * m.end.y;
+                       if (!mergedMoves[key])
+                               mergedMoves[key] = m;
+                       else
+                       {
+                               for (let i=1; i<m.vanish.length; i++)
+                                       mergedMoves[key].vanish.push(m.vanish[i]);
+                       }
+               });
+               // Finally return an array
+               moves = [];
+               Object.keys(mergedMoves).forEach(k => { moves.push(mergedMoves[k]); });
+               return moves;
+       }
+
+       // Withdrawer
+       addQueenCaptures(moves, byChameleon)
+       {
+               if (moves.length == 0)
+                       return;
+               const [x,y] = [moves[0].start.x,moves[0].start.y];
                const V = VariantRules;
                const adjacentSteps = V.steps[V.ROOK].concat(V.steps[V.BISHOP]);
                let capturingDirections = [];
-               const color = this.getColor(x,y);
+               const color = this.turn;
                const oppCol = this.getOppCol(color);
+               const [sizeX,sizeY] = V.size;
                adjacentSteps.forEach(step => {
                        const [i,j] = [x+step[0],y+step[1]];
-                       if (this.board[i][j] != V.EMPTY && this.getColor(i,j) == oppCol)
+                       if (i>=0 && i<sizeX && j>=0 && j<sizeY
+                               && this.board[i][j] != V.EMPTY && this.getColor(i,j) == oppCol
+                               && (!byChameleon || this.getPiece(i,j) == V.QUEEN))
+                       {
                                capturingDirections.push(step);
+                       }
                });
                moves.forEach(m => {
                        const step = [
                                m.end.x!=x ? (m.end.x-x)/Math.abs(m.end.x-x) : 0,
                                m.end.y!=y ? (m.end.y-y)/Math.abs(m.end.y-y) : 0
                        ];
-                       // NOTE: includes() function does not work on complex array elements
+                       // NOTE: includes() and even _.isEqual() functions fail...
                        // TODO: this test should be done only once per direction
-                       if (capturingDirection.some(dir => _.isEqual(dir, step)))
+                       if (capturingDirections.some(dir =>
+                               { return (dir[0]==-step[0] && dir[1]==-step[1]); }))
                        {
                                const [i,j] = [x-step[0],y-step[1]];
                                m.vanish.push(new PiPo({
@@ -224,8 +390,16 @@ class UltimaRules extends ChessRules
                });
        }
 
+       getPotentialQueenMoves(sq)
+       {
+               let moves = super.getPotentialQueenMoves(sq);
+               this.addQueenCaptures(moves);
+               return moves;
+       }
+
        getPotentialImmobilizerMoves(sq)
        {
+               // Immobilizer doesn't capture
                return super.getPotentialQueenMoves(sq);
        }
 
@@ -238,40 +412,144 @@ class UltimaRules extends ChessRules
 
        // isAttacked() is OK because the immobilizer doesn't take
 
+       // TODO: check if any pawn can reach capturing square + !immobilized
        isAttackedByPawn([x,y], colors)
        {
                // Square (x,y) must be surrounded by two enemy pieces,
-               // and one of them at least should be a pawn
+               // and one of them at least should be a pawn.
+               const dirs = [ [1,0],[0,1],[1,1],[-1,1] ];
+               const [sizeX,sizeY] = VariantRules.size;
+               for (let dir of dirs)
+               {
+                       const [i1,j1] = [x-dir[0],y-dir[1]]; //"before"
+                       const [i2,j2] = [x+dir[0],y+dir[1]]; //"after"
+                       if (i1>=0 && i1<sizeX && i2>=0 && i2<sizeX
+                               && j1>=0 && j1<sizeY && j2>=0 && j2<sizeY
+                               && this.board[i1][j1]!=VariantRules.EMPTY
+                               && this.board[i2][j2]!=VariantRules.EMPTY
+                               && colors.includes(this.getColor(i1,j1))
+                               && colors.includes(this.getColor(i2,j2))
+                               && [this.getPiece(i1,j1),this.getPiece(i2,j2)].includes(VariantRules.PAWN))
+                       {
+                               return true;
+                       }
+               }
                return false;
        }
 
-       isAttackedByRook(sq, colors)
+       // TODO: check if enemy's rook can reach capturing squares + !immobilized
+       isAttackedByRook([x,y], colors)
        {
-               // Enemy king must be on same file and a rook on same row (or reverse)
+               const [sizeX,sizeY] = VariantRules.size;
+               // King must be on same column and a rook on same row (or reverse)
+               if (x == this.kingPos[colors[0]][0]) //using colors[0], only element in this case
+               {
+                       // Look for enemy rook on this column
+                       for (let i=0; i<sizeY; i++)
+                       {
+                               if (this.board[x][i] != VariantRules.EMPTY
+                                       && colors.includes(this.getColor(x,i))
+                                       && this.getPiece(x,i) == VariantRules.ROOK)
+                               {
+                                       return true;
+                               }
+                       }
+               }
+               else if (y == this.kingPos[colors[0]][1])
+               {
+                       // Look for enemy rook on this row
+                       for (let i=0; i<sizeX; i++)
+                       {
+                               if (this.board[i][y] != VariantRules.EMPTY
+                                       && colors.includes(this.getColor(i,y))
+                                       && this.getPiece(i,y) == VariantRules.ROOK)
+                               {
+                                       return true;
+                               }
+                       }
+               }
+               return false;
        }
 
-       isAttackedByKnight(sq, colors)
+       isAttackedByKnight([x,y], colors)
        {
                // Square (x,y) must be on same line as a knight,
                // and there must be empty square(s) behind.
+               const V = VariantRules;
+               const steps = V.steps[V.ROOK].concat(V.steps[V.BISHOP]);
+               const [sizeX,sizeY] = V.size;
+               outerLoop:
+               for (let step of steps)
+               {
+                       const [i0,j0] = [x+step[0],y+step[1]];
+                       if (i0>=0 && i0<sizeX && j0>=0 && j0<sizeY && this.board[i0][j0] == V.EMPTY)
+                       {
+                               // Try in opposite direction:
+                               let [i,j] = [x-step[0],y-step[1]];
+                               while (i>=0 && i<sizeX && j>=0 && j<sizeY && this.board[i][j] == V.EMPTY)
+                               {
+                                       i -= step[0];
+                                       j -= step[1];
+                               }
+                               if (i>=0 && i<sizeX && j>=0 && j<sizeY && colors.includes(this.getColor(i,j))
+                                       && this.getPiece(i,j) == V.KNIGHT)
+                               {
+                                       if (!this.isImmobilized([i,j]))
+                                               return true;
+                               }
+                       }
+               }
+               return false;
        }
 
-       isAttackedByBishop(sq, colors)
+       isAttackedByBishop([x,y], colors)
        {
-               // switch on piece nature on square sq: a chameleon attack as this piece
-               // ==> call the appropriate isAttackedBy... (exception of immobilizers)
-               // Other exception: a chameleon cannot attack a chameleon (seemingly...)
+               // We cheat a little here: since this function is used exclusively for king,
+               // it's enough to check the immediate surrounding of the square.
+               const V = VariantRules;
+               const adjacentSteps = V.steps[V.ROOK].concat(V.steps[V.BISHOP]);
+               const [sizeX,sizeY] = V.size;
+               for (let step of adjacentSteps)
+               {
+                       const [i,j] = [x+step[0],y+step[1]];
+                       if (i>=0 && i<sizeX && j>=0 && j<sizeY && this.board[i][j]!=V.EMPTY
+                               && colors.includes(this.getColor(i,j)) && this.getPiece(i,j) == V.BISHOP)
+                       {
+                               return true; //bishops are never immobilized
+                       }
+               }
+               return false;
        }
 
-       isAttackedByQueen(sq, colors)
+       isAttackedByQueen([x,y], colors)
        {
                // Square (x,y) must be adjacent to a queen, and the queen must have
                // some free space in the opposite direction from (x,y)
+               const V = VariantRules;
+               const adjacentSteps = V.steps[V.ROOK].concat(V.steps[V.BISHOP]);
+               const [sizeX,sizeY] = V.size;
+               for (let step of adjacentSteps)
+               {
+                       const sq2 = [x+2*step[0],y+2*step[1]];
+                       if (sq2[0]>=0 && sq2[0]<sizeX && sq2[1]>=0 && sq2[1]<sizeY
+                               && this.board[sq2[0]][sq2[1]] == V.EMPTY)
+                       {
+                               const sq1 = [x+step[0],y+step[1]];
+                               if (this.board[sq1[0]][sq1[1]] != V.EMPTY
+                                       && colors.includes(this.getColor(sq1[0],sq1[1]))
+                                       && this.getPiece(sq1[0],sq1[1]) == V.QUEEN
+                                       && !this.isImmobilized(sq1))
+                               {
+                                       return true;
+                               }
+                       }
+               }
+               return false;
        }
 
        updateVariables(move)
        {
-               // Just update king position
+               // Just update king(s) position(s)
                const piece = this.getPiece(move.start.x,move.start.y);
                const c = this.getColor(move.start.x,move.start.y);
                if (piece == VariantRules.KING && move.appear.length > 0)