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[vchess.git] / public / javascripts / variants / Checkered.js
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1class CheckeredRules extends ChessRules
2{
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3 static getPpath(b)
4 {
5 return b[0]=='c' ? "Checkered/"+b : b;
6 }
7 static board2fen(b)
8 {
9 const checkered_codes = {
10 'p': 's',
11 'q': 't',
12 'r': 'u',
13 'b': 'c',
14 'n': 'o',
15 };
16 if (b[0]=="c")
17 return checkered_codes[b[1]];
18 return ChessRules.board2fen(b);
19 }
20 static fen2board(f)
21 {
22 const checkered_pieces = {
23 's': 'p',
24 't': 'q',
25 'u': 'r',
26 'c': 'b',
27 'o': 'n',
28 };
29 if (Object.keys(checkered_pieces).includes(f))
30 return 'c'+checkered_pieces[f];
31 return ChessRules.fen2board(f);
32 }
33
2526c041 34 setFlags(fen)
1d184b4c 35 {
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36 super.setFlags(fen); //castleFlags
37 this.pawnFlags =
38 {
39 "w": new Array(8), //pawns can move 2 squares?
40 "b": new Array(8)
41 };
42 const flags = fen.split(" ")[1].substr(4); //skip first 4 digits, for castle
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43 for (let c of ['w','b'])
44 {
45 for (let i=0; i<8; i++)
2526c041 46 this.pawnFlags[c][i] = (flags.charAt((c=='w'?0:8)+i) == '1');
1d184b4c 47 }
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48 }
49
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50 // Aggregates flags into one object
51 get flags() {
52 return [this.castleFlags, this.pawnFlags];
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53 }
54
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55 // Reverse operation
56 parseFlags(flags)
1d184b4c 57 {
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58 this.castleFlags = flags[0];
59 this.pawnFlags = flags[1];
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60 }
61
2526c041 62 canTake([x1,y1], [x2,y2])
1d184b4c 63 {
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64 const color1 = this.getColor(x1,y1);
65 const color2 = this.getColor(x2,y2);
66 // Checkered aren't captured
67 return color1 != color2 && color2 != 'c' && (color1 != 'c' || color2 != this.turn);
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68 }
69
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70 // Post-processing: apply "checkerization" of standard moves
71 getPotentialMovesFrom([x,y])
1d184b4c 72 {
2526c041 73 let standardMoves = super.getPotentialMovesFrom([x,y]);
aea1443e 74 const lastRank = this.turn == "w" ? 0 : 7;
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75 if (this.getPiece(x,y) == VariantRules.KING)
76 return standardMoves; //king has to be treated differently (for castles)
1d184b4c 77 let moves = [];
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78 standardMoves.forEach(m => {
79 if (m.vanish[0].p == VariantRules.PAWN && Math.abs(m.end.x-m.start.x)==2
80 && !this.pawnFlags[this.turn][m.start.y])
1d184b4c 81 {
2526c041 82 return; //skip forbidden 2-squares jumps
1d184b4c 83 }
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84 if (m.vanish.length == 1)
85 moves.push(m); //no capture
86 else
1d184b4c 87 {
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88 // A capture occured (m.vanish.length == 2)
89 m.appear[0].c = "c";
aea1443e 90 moves.push(m);
68f5ccc8 91 if (m.appear[0].p != m.vanish[1].p //avoid promotions (already treated):
aea1443e 92 && (m.vanish[0].p != VariantRules.PAWN || m.end.x != lastRank))
1d184b4c 93 {
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94 // Add transformation into captured piece
95 let m2 = JSON.parse(JSON.stringify(m));
aea1443e 96 m2.appear[0].p = m.vanish[1].p;
2526c041 97 moves.push(m2);
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98 }
99 }
2526c041 100 });
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101 return moves;
102 }
103
46302e64 104 canIplay(side, [x,y])
1d184b4c 105 {
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106 return ((side=='w' && this.moves.length%2==0) || (side=='b' && this.moves.length%2==1))
107 && [side,'c'].includes(this.getColor(x,y));
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108 }
109
110 // Does m2 un-do m1 ? (to disallow undoing checkered moves)
111 oppositeMoves(m1, m2)
112 {
113 return m1.appear.length == 1 && m2.appear.length == 1
114 && m1.vanish.length == 1 && m2.vanish.length == 1
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115 && m1.start.x == m2.end.x && m1.end.x == m2.start.x
116 && m1.start.y == m2.end.y && m1.end.y == m2.start.y
117 && m1.appear[0].c == m2.vanish[0].c && m1.appear[0].p == m2.vanish[0].p
118 && m1.vanish[0].c == m2.appear[0].c && m1.vanish[0].p == m2.appear[0].p;
119 }
120
121 filterValid(moves)
122 {
123 if (moves.length == 0)
124 return [];
46302e64 125 const color = this.turn;
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126 return moves.filter(m => {
127 const L = this.moves.length;
128 if (L > 0 && this.oppositeMoves(this.moves[L-1], m))
129 return false;
46302e64 130 return !this.underCheck(m);
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131 });
132 }
133
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134 isAttackedByPawn([x,y], colors)
135 {
136 for (let c of colors)
137 {
138 const color = (c=="c" ? this.turn : c);
139 let pawnShift = (color=="w" ? 1 : -1);
140 if (x+pawnShift>=0 && x+pawnShift<8)
141 {
142 for (let i of [-1,1])
143 {
144 if (y+i>=0 && y+i<8 && this.getPiece(x+pawnShift,y+i)==VariantRules.PAWN
145 && this.getColor(x+pawnShift,y+i)==c)
146 {
147 return true;
148 }
149 }
150 }
151 }
152 return false;
153 }
1d184b4c 154
46302e64 155 underCheck(move)
1d184b4c 156 {
46302e64 157 const color = this.turn;
1d184b4c 158 this.play(move);
46302e64 159 let res = this.isAttacked(this.kingPos[color], [this.getOppCol(color),'c']);
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160 this.undo(move);
161 return res;
162 }
163
46302e64 164 getCheckSquares(move)
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165 {
166 this.play(move);
46302e64 167 const color = this.turn;
cd4cad04 168 this.moves.push(move); //artifically change turn, for checkered pawns (TODO)
46302e64 169 const kingAttacked = this.isAttacked(this.kingPos[color], [this.getOppCol(color),'c']);
bd6ff57c 170 let res = kingAttacked
46302e64 171 ? [ JSON.parse(JSON.stringify(this.kingPos[color])) ] //need to duplicate!
bd6ff57c 172 : [ ];
cd4cad04 173 this.moves.pop();
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174 this.undo(move);
175 return res;
176 }
177
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178 updateVariables(move)
179 {
1d184b4c 180 const c = this.getColor(move.start.x,move.start.y);
1d184b4c 181 if (c != 'c') //checkered not concerned by castle flags
2526c041 182 super.updateVariables(move);
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183
184 // Does it turn off a 2-squares pawn flag?
185 const secondRank = [1,6];
186 if (secondRank.includes(move.start.x) && move.vanish[0].p == VariantRules.PAWN)
2526c041 187 this.pawnFlags[move.start.x==6 ? "w" : "b"][move.start.y] = false;
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188 }
189
46302e64 190 checkGameEnd()
1d184b4c 191 {
46302e64 192 const color = this.turn;
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193 this.moves.length++; //artifically change turn, for checkered pawns (TODO)
194 const res = this.isAttacked(this.kingPos[color], [this.getOppCol(color),'c'])
195 ? (color == "w" ? "0-1" : "1-0")
196 : "1/2";
197 this.moves.length--;
198 return res;
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199 }
200
201 evalPosition()
202 {
203 const [sizeX,sizeY] = VariantRules.size;
204 let evaluation = 0;
205 //Just count material for now, considering checkered neutral (...)
206 for (let i=0; i<sizeX; i++)
207 {
208 for (let j=0; j<sizeY; j++)
209 {
210 if (this.board[i][j] != VariantRules.EMPTY)
211 {
212 const sqColor = this.getColor(i,j);
213 const sign = sqColor == "w" ? 1 : (sqColor=="b" ? -1 : 0);
214 evaluation += sign * VariantRules.VALUES[this.getPiece(i,j)];
215 }
216 }
217 }
218 return evaluation;
219 }
220
221 static GenRandInitFen()
222 {
f3802fcd 223 return ChessRules.GenRandInitFen() + "1111111111111111"; //add 16 pawns flags
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224 }
225
226 getFlagsFen()
227 {
2526c041 228 let fen = super.getFlagsFen();
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229 // Add pawns flags
230 for (let c of ['w','b'])
231 {
232 for (let i=0; i<8; i++)
2526c041 233 fen += this.pawnFlags[c][i] ? '1' : '0';
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234 }
235 return fen;
236 }
237
238 getNotation(move)
239 {
240 if (move.appear.length == 2)
241 {
242 // Castle
243 if (move.end.y < move.start.y)
244 return "0-0-0";
245 else
246 return "0-0";
247 }
248
249 // Translate final square
250 let finalSquare =
251 String.fromCharCode(97 + move.end.y) + (VariantRules.size[0]-move.end.x);
252
253 let piece = this.getPiece(move.start.x, move.start.y);
254 if (piece == VariantRules.PAWN)
255 {
256 // Pawn move
257 let notation = "";
258 if (move.vanish.length > 1)
259 {
260 // Capture
261 let startColumn = String.fromCharCode(97 + move.start.y);
262 notation = startColumn + "x" + finalSquare + "=" + move.appear[0].p.toUpperCase();
263 }
264 else //no capture
265 notation = finalSquare;
266 if (move.appear.length > 0 && piece != move.appear[0].p) //promotion
267 notation += "=" + move.appear[0].p.toUpperCase();
268 return notation;
269 }
270
271 else
272 {
273 // Piece movement
274 return piece.toUpperCase() + (move.vanish.length > 1 ? "x" : "") + finalSquare
275 + (move.vanish.length > 1 ? "=" + move.appear[0].p.toUpperCase() : "");
276 }
277 }
278}