Some refactoring in variants logic: more robust FEN handling (untested)

[vchess.git] / public / javascripts / variants / Magnetic.js

diff --git a/public/javascripts/variants/Magnetic.js b/public/javascripts/variants/Magnetic.js
index 2e90e6c..225489e 100644 (file)
--- a/public/javascripts/variants/Magnetic.js
+++ b/public/javascripts/variants/Magnetic.js
@@ -1,8 +1,13 @@
 class MagneticRules extends ChessRules
 {
-       getEpSquare(move)
+       static get HasEnpassant { return false; }
+
+       setOtherVariables(fen)
        {
-               return undefined; //no en-passant
+               // No en-passant:
+               const parsedFen = V.ParseFen(fen);
+               this.setFlags(fenParsed.flags);
+               this.scanKingsRooks(fen);
        }
 
        getPotentialMovesFrom([x,y])
@@ -19,6 +24,67 @@ class MagneticRules extends ChessRules
                return moves;
        }
 
+       getPotentialPawnMoves([x,y])
+       {
+               const color = this.turn;
+               let moves = [];
+               const [sizeX,sizeY] = [V.size.x,V.size.y];
+               const shift = (color == "w" ? -1 : 1);
+               const firstRank = (color == 'w' ? sizeX-1 : 0);
+               const startRank = (color == "w" ? sizeX-2 : 1);
+               const lastRank = (color == "w" ? 0 : sizeX-1);
+
+               if (x+shift >= 0 && x+shift < sizeX && x+shift != lastRank)
+               {
+                       // Normal moves
+                       if (this.board[x+shift][y] == V.EMPTY)
+                       {
+                               moves.push(this.getBasicMove([x,y], [x+shift,y]));
+                               // Next condition because variants with pawns on 1st rank allow them to jump
+                               if ([startRank,firstRank].includes(x) && this.board[x+2*shift][y] == V.EMPTY)
+                               {
+                                       // Two squares jump
+                                       moves.push(this.getBasicMove([x,y], [x+2*shift,y]));
+                               }
+                       }
+                       // Captures
+                       if (y>0 && this.board[x+shift][y-1] != V.EMPTY
+                               && this.canTake([x,y], [x+shift,y-1]))
+                       {
+                               moves.push(this.getBasicMove([x,y], [x+shift,y-1]));
+                       }
+                       if (y<sizeY-1 && this.board[x+shift][y+1] != V.EMPTY
+                               && this.canTake([x,y], [x+shift,y+1]))
+                       {
+                               moves.push(this.getBasicMove([x,y], [x+shift,y+1]));
+                       }
+               }
+
+               if (x+shift == lastRank)
+               {
+                       // Promotion
+                       const pawnColor = this.getColor(x,y); //can be different for checkered
+                       let promotionPieces = [V.ROOK,V.KNIGHT,V.BISHOP,V.QUEEN];
+                       promotionPieces.forEach(p => {
+                               // Normal move
+                               if (this.board[x+shift][y] == V.EMPTY)
+                                       moves.push(this.getBasicMove([x,y], [x+shift,y], {c:pawnColor,p:p}));
+                               // Captures
+                               if (y>0 && this.board[x+shift][y-1] != V.EMPTY
+                                       && this.canTake([x,y], [x+shift,y-1]))
+                               {
+                                       moves.push(this.getBasicMove([x,y], [x+shift,y-1], {c:pawnColor,p:p}));
+                               }
+                               if (y<sizeY-1 && this.board[x+shift][y+1] != V.EMPTY
+                                       && this.canTake([x,y], [x+shift,y+1]))
+                               {
+                                       moves.push(this.getBasicMove([x,y], [x+shift,y+1], {c:pawnColor,p:p}));
+                               }
+                       });
+               }
+               return moves; //no en-passant
+       }
+
        // Complete a move with magnetic actions
        // TODO: job is done multiple times for (normal) promotions.
        applyMagneticLaws(move)
@@ -154,8 +220,8 @@ class MagneticRules extends ChessRules
                this.play(move);
                // The only way to be "under check" is to have lost the king (thus game over)
                let res = this.kingPos[c][0] < 0
-                       ? [ JSON.parse(JSON.stringify(saveKingPos)) ]
-                       : [ ];
+                       ? [JSON.parse(JSON.stringify(saveKingPos))]
+                       : [];
                this.undo(move);
                return res;
        }
@@ -210,7 +276,8 @@ class MagneticRules extends ChessRules
                return this.turn == "w" ? "0-1" : "1-0";
        }
 
-       static get THRESHOLD_MATE() {
+       static get THRESHOLD_MATE()
+       {
                return 500; //checkmates evals may be slightly below 1000
        }
 }