public/javascripts/components/game.js

   1 Vue.component('my-game', {
   2     data: function() {
   3         return {
   4             vr: null, //object to check moves, store them, FEN..
   5             mycolor: "w",
   6             possibleMoves: [], //filled after each valid click/dragstart
   7             choices: [], //promotion pieces, or checkered captures... (contain possible pieces)
   8             start: {}, //pixels coordinates + id of starting square (click or drag)
   9             selectedPiece: null, //moving piece (or clicked piece)
  10             conn: null, //socket messages
  11             score: "*", //'*' means 'unfinished'
  12             mode: "idle", //human, computer or idle (when not playing)
  13             oppid: "", //opponent ID in case of HH game
  14             oppConnected: false,
  15             seek: false,
  16             fenStart: "",
  17             incheck: [],
  18             pgnTxt: "",
  19             expert: document.cookie.length>0 ? document.cookie.substr(-1)=="1" : false,
  20             gameId: "", //used to limit computer moves' time
  21         };
  22     },
  23     render(h) {
  24         const [sizeX,sizeY] = VariantRules.size;
  25         // Precompute hints squares to facilitate rendering
  26         let hintSquares = doubleArray(sizeX, sizeY, false);
  27         this.possibleMoves.forEach(m => { hintSquares[m.end.x][m.end.y] = true; });
  28         // Also precompute in-check squares
  29         let incheckSq = doubleArray(sizeX, sizeY, false);
  30         this.incheck.forEach(sq => { incheckSq[sq[0]][sq[1]] = true; });
  31         let elementArray = [];
  32         const playingHuman = (this.mode == "human");
  33         const playingComp = (this.mode == "computer");
  34         let actionArray = [
  35             h('button',
  36                 {
  37                     on: { click: this.clickGameSeek },
  38                     attrs: { "aria-label": 'New game VS human' },
  39                     'class': {
  40                         "tooltip": true,
  41                         "bottom": true, //display below
  42                         "seek": this.seek,
  43                         "playing": playingHuman,
  44                     },
  45                 },
  46                 [h('i', { 'class': { "material-icons": true } }, "accessibility")]),
  47             h('button',
  48                 {
  49                     on: { click: this.clickComputerGame },
  50                     attrs: { "aria-label": 'New game VS computer' },
  51                     'class': {
  52                         "tooltip":true,
  53                         "bottom": true,
  54                         "playing": playingComp,
  55                     },
  56                 },
  57                 [h('i', { 'class': { "material-icons": true } }, "computer")])
  58         ];
  59         if (!!this.vr)
  60         {
  61             const square00 = document.getElementById("sq-0-0");
  62             const squareWidth = !!square00
  63                 ? parseFloat(window.getComputedStyle(square00).width.slice(0,-2))
  64                 : 0;
  65             const indicWidth = (squareWidth>0 ? squareWidth/2 : 20);
  66             if (this.mode == "human")
  67             {
  68                 let connectedIndic = h(
  69                     'div',
  70                     {
  71                         "class": {
  72                             "topindicator": true,
  73                             "indic-left": true,
  74                             "connected": this.oppConnected,
  75                             "disconnected": !this.oppConnected,
  76                         },
  77                         style: {
  78                             "width": indicWidth + "px",
  79                             "height": indicWidth + "px",
  80                         },
  81                     }
  82                 );
  83                 elementArray.push(connectedIndic);
  84             }
  85             let turnIndic = h(
  86                 'div',
  87                 {
  88                     "class": {
  89                         "topindicator": true,
  90                         "indic-right": true,
  91                         "white-turn": this.vr.turn=="w",
  92                         "black-turn": this.vr.turn=="b",
  93                     },
  94                     style: {
  95                         "width": indicWidth + "px",
  96                         "height": indicWidth + "px",
  97                     },
  98                 }
  99             );
 100             elementArray.push(turnIndic);
 101             let expertSwitch = h(
 102                 'button',
 103                 {
 104                     on: { click: this.toggleExpertMode },
 105                     attrs: { "aria-label": 'Toggle expert mode' },
 106                     'class': {
 107                         "tooltip":true,
 108                         "topindicator": true,
 109                         "indic-right": true,
 110                         "expert-switch": true,
 111                         "expert-mode": this.expert,
 112                     },
 113                 },
 114                 [h('i', { 'class': { "material-icons": true } }, "remove_red_eye")]
 115             );
 116             elementArray.push(expertSwitch);
 117             let choices = h('div',
 118                 {
 119                     attrs: { "id": "choices" },
 120                     'class': { 'row': true },
 121                     style: {
 122                         "display": this.choices.length>0?"block":"none",
 123                         "top": "-" + ((sizeY/2)*squareWidth+squareWidth/2) + "px",
 124                         "width": (this.choices.length * squareWidth) + "px",
 125                         "height": squareWidth + "px",
 126                     },
 127                 },
 128                 this.choices.map( m => { //a "choice" is a move
 129                     return h('div',
 130                         {
 131                             'class': {
 132                                 'board': true,
 133                                 ['board'+sizeY]: true,
 134                             },
 135                             style: {
 136                                 'width': (100/this.choices.length) + "%",
 137                                 'padding-bottom': (100/this.choices.length) + "%",
 138                             },
 139                         },
 140                         [h('img',
 141                             {
 142                                 attrs: { "src": '/images/pieces/' +
 143                                     VariantRules.getPpath(m.appear[0].c+m.appear[0].p) + '.svg' },
 144                                 'class': { 'choice-piece': true },
 145                                 on: { "click": e => { this.play(m); this.choices=[]; } },
 146                             })
 147                         ]
 148                     );
 149                 })
 150             );
 151             // Create board element (+ reserves if needed by variant or mode)
 152             let gameDiv = h('div',
 153                 {
 154                     'class': { 'game': true },
 155                 },
 156                 [_.range(sizeX).map(i => {
 157                     let ci = this.mycolor=='w' ? i : sizeX-i-1;
 158                     return h(
 159                         'div',
 160                         {
 161                             'class': {
 162                                 'row': true,
 163                             },
 164                             style: { 'opacity': this.choices.length>0?"0.5":"1" },
 165                         },
 166                         _.range(sizeY).map(j => {
 167                             let cj = this.mycolor=='w' ? j : sizeY-j-1;
 168                             let elems = [];
 169                             if (this.vr.board[ci][cj] != VariantRules.EMPTY)
 170                             {
 171                                 elems.push(
 172                                     h(
 173                                         'img',
 174                                         {
 175                                             'class': {
 176                                                 'piece': true,
 177                                                 'ghost': !!this.selectedPiece
 178                                                     && this.selectedPiece.parentNode.id == "sq-"+ci+"-"+cj,
 179                                             },
 180                                             attrs: {
 181                                                 src: "/images/pieces/" +
 182                                                     VariantRules.getPpath(this.vr.board[ci][cj]) + ".svg",
 183                                             },
 184                                         }
 185                                     )
 186                                 );
 187                             }
 188                             if (!this.expert && hintSquares[ci][cj])
 189                             {
 190                                 elems.push(
 191                                     h(
 192                                         'img',
 193                                         {
 194                                             'class': {
 195                                                 'mark-square': true,
 196                                             },
 197                                             attrs: {
 198                                                 src: "/images/mark.svg",
 199                                             },
 200                                         }
 201                                     )
 202                                 );
 203                             }
 204                             const lm = this.vr.lastMove;
 205                             const showLight = !this.expert &&
 206                                 (this.mode!="idle" || this.cursor==this.vr.moves.length);
 207                             return h(
 208                                 'div',
 209                                 {
 210                                     'class': {
 211                                         'board': true,
 212                                         ['board'+sizeY]: true,
 213                                         'light-square': (i+j)%2==0,
 214                                         'dark-square': (i+j)%2==1,
 215                                         'highlight': showLight && !!lm && _.isMatch(lm.end, {x:ci,y:cj}),
 216                                         'incheck': showLight && incheckSq[ci][cj],
 217                                     },
 218                                     attrs: {
 219                                         id: this.getSquareId({x:ci,y:cj}),
 220                                     },
 221                                 },
 222                                 elems
 223                             );
 224                         })
 225                     );
 226                 }), choices]
 227             );
 228             if (this.mode != "idle")
 229             {
 230                 actionArray.push(
 231                     h('button',
 232                         {
 233                             on: { click: this.resign },
 234                             attrs: { "aria-label": 'Resign' },
 235                             'class': {
 236                                 "tooltip":true,
 237                                 "bottom": true,
 238                             },
 239                         },
 240                         [h('i', { 'class': { "material-icons": true } }, "flag")])
 241                 );
 242             }
 243             else if (this.vr.moves.length > 0)
 244             {
 245                 // A game finished, and another is not started yet: allow navigation
 246                 actionArray = actionArray.concat([
 247                     h('button',
 248                         {
 249                             style: { "margin-left": "30px" },
 250                             on: { click: e => this.undo() },
 251                             attrs: { "aria-label": 'Undo' },
 252                             'class': {
 253                                 "tooltip":true,
 254                                 "bottom": true,
 255                             },
 256                         },
 257                         [h('i', { 'class': { "material-icons": true } }, "fast_rewind")]),
 258                     h('button',
 259                         {
 260                             on: { click: e => this.play() },
 261                             attrs: { "aria-label": 'Play' },
 262                             'class': {
 263                                 "tooltip":true,
 264                                 "bottom": true,
 265                             },
 266                         },
 267                         [h('i', { 'class': { "material-icons": true } }, "fast_forward")]),
 268                     ]
 269                 );
 270             }
 271             elementArray.push(gameDiv);
 272             if (!!this.vr.reserve)
 273             {
 274                 const shiftIdx = (this.mycolor=="w" ? 0 : 1);
 275                 let myReservePiecesArray = [];
 276                 for (let i=0; i<VariantRules.RESERVE_PIECES.length; i++)
 277                 {
 278                     myReservePiecesArray.push(h('div',
 279                     {
 280                         'class': {'board':true, ['board'+sizeY]:true},
 281                         attrs: { id: this.getSquareId({x:sizeX+shiftIdx,y:i}) }
 282                     },
 283                     [
 284                         h('img',
 285                         {
 286                             'class': {"piece":true},
 287                             attrs: {
 288                                 "src": "/images/pieces/" +
 289                                     this.vr.getReservePpath(this.mycolor,i) + ".svg",
 290                             }
 291                         }),
 292                         h('sup',
 293                             {style: { "padding-left":"40%"} },
 294                             [ this.vr.reserve[this.mycolor][VariantRules.RESERVE_PIECES[i]] ]
 295                         )
 296                     ]));
 297                 }
 298                 let oppReservePiecesArray = [];
 299                 const oppCol = this.vr.getOppCol(this.mycolor);
 300                 for (let i=0; i<VariantRules.RESERVE_PIECES.length; i++)
 301                 {
 302                     oppReservePiecesArray.push(h('div',
 303                     {
 304                         'class': {'board':true, ['board'+sizeY]:true},
 305                         attrs: { id: this.getSquareId({x:sizeX+(1-shiftIdx),y:i}) }
 306                     },
 307                     [
 308                         h('img',
 309                         {
 310                             'class': {"piece":true},
 311                             attrs: {
 312                                 "src": "/images/pieces/" +
 313                                     this.vr.getReservePpath(oppCol,i) + ".svg",
 314                             }
 315                         }),
 316                         h('sup',
 317                             {style: { "padding-left":"40%"} },
 318                             [ this.vr.reserve[oppCol][VariantRules.RESERVE_PIECES[i]] ]
 319                         )
 320                     ]));
 321                 }
 322                 let reserves = h('div',
 323                     {
 324                         'class':{'game':true},
 325                         style: {"margin-bottom": "20px"},
 326                     },
 327                     [
 328                         h('div',
 329                             {
 330                                 'class': { 'row': true },
 331                                 style: {"margin-bottom": "15px"},
 332                             },
 333                             myReservePiecesArray
 334                         ),
 335                         h('div',
 336                             { 'class': { 'row': true }},
 337                             oppReservePiecesArray
 338                         )
 339                     ]
 340                 );
 341                 elementArray.push(reserves);
 342             }
 343             const eogMessage = this.getEndgameMessage(this.score);
 344             const modalEog = [
 345                 h('input',
 346                     {
 347                         attrs: { "id": "modal-eog", type: "checkbox" },
 348                         "class": { "modal": true },
 349                     }),
 350                 h('div',
 351                     {
 352                         attrs: { "role": "dialog", "aria-labelledby": "dialog-title" },
 353                     },
 354                     [
 355                         h('div',
 356                             {
 357                                 "class": { "card": true, "smallpad": true },
 358                             },
 359                             [
 360                                 h('label',
 361                                     {
 362                                         attrs: { "for": "modal-eog" },
 363                                         "class": { "modal-close": true },
 364                                     }
 365                                 ),
 366                                 h('h3',
 367                                     {
 368                                         "class": { "section": true },
 369                                         domProps: { innerHTML: eogMessage },
 370                                     }
 371                                 )
 372                             ]
 373                         )
 374                     ]
 375                 )
 376             ];
 377             elementArray = elementArray.concat(modalEog);
 378         }
 379         const modalNewgame = [
 380             h('input',
 381                 {
 382                     attrs: { "id": "modal-newgame", type: "checkbox" },
 383                     "class": { "modal": true },
 384                 }),
 385             h('div',
 386                 {
 387                     attrs: { "role": "dialog", "aria-labelledby": "dialog-title" },
 388                 },
 389                 [
 390                     h('div',
 391                         {
 392                             "class": { "card": true, "smallpad": true },
 393                         },
 394                         [
 395                             h('label',
 396                                 {
 397                                     attrs: { "id": "close-newgame", "for": "modal-newgame" },
 398                                     "class": { "modal-close": true },
 399                                 }
 400                             ),
 401                             h('h3',
 402                                 {
 403                                     "class": { "section": true },
 404                                     domProps: { innerHTML: "New game" },
 405                                 }
 406                             ),
 407                             h('p',
 408                                 {
 409                                     "class": { "section": true },
 410                                     domProps: { innerHTML: "Waiting for opponent..." },
 411                                 }
 412                             )
 413                         ]
 414                     )
 415                 ]
 416             )
 417         ];
 418         elementArray = elementArray.concat(modalNewgame);
 419         const actions = h('div',
 420             {
 421                 attrs: { "id": "actions" },
 422                 'class': { 'text-center': true },
 423             },
 424             actionArray
 425         );
 426         elementArray.push(actions);
 427         if (this.score != "*")
 428         {
 429             elementArray.push(
 430                 h('div',
 431                     { attrs: { id: "pgn-div" } },
 432                     [
 433                         h('a',
 434                             {
 435                                 attrs: {
 436                                     id: "download",
 437                                     href: "#",
 438                                 }
 439                             }
 440                         ),
 441                         h('p',
 442                             {
 443                                 attrs: { id: "pgn-game" },
 444                                 on: { click: this.download },
 445                                 domProps: { innerHTML: this.pgnTxt }
 446                             }
 447                         )
 448                     ]
 449                 )
 450             );
 451         }
 452         else if (this.mode != "idle")
 453         {
 454             // Show current FEN (at least for debug)
 455             elementArray.push(
 456                 h('div',
 457                     { attrs: { id: "fen-div" } },
 458                     [
 459                         h('p',
 460                             {
 461                                 attrs: { id: "fen-string" },
 462                                 domProps: { innerHTML: this.vr.getBaseFen() }
 463                             }
 464                         )
 465                     ]
 466                 )
 467             );
 468         }
 469         return h(
 470             'div',
 471             {
 472                 'class': {
 473                     "col-sm-12":true,
 474                     "col-md-8":true,
 475                     "col-md-offset-2":true,
 476                     "col-lg-6":true,
 477                     "col-lg-offset-3":true,
 478                 },
 479                 // NOTE: click = mousedown + mouseup
 480                 on: {
 481                     mousedown: this.mousedown,
 482                     mousemove: this.mousemove,
 483                     mouseup: this.mouseup,
 484                     touchstart: this.mousedown,
 485                     touchmove: this.mousemove,
 486                     touchend: this.mouseup,
 487                 },
 488             },
 489             elementArray
 490         );
 491     },
 492     created: function() {
 493         const url = socketUrl;
 494         const continuation = (localStorage.getItem("variant") === variant);
 495         this.myid = continuation
 496             ? localStorage.getItem("myid")
 497             // random enough (TODO: function)
 498             : (Date.now().toString(36) + Math.random().toString(36).substr(2, 7)).toUpperCase();
 499         if (!continuation)
 500         {
 501             // HACK: play a small silent sound to allow "new game" sound later if tab not focused
 502             new Audio("/sounds/silent.mp3").play().then(() => {}).catch(err => {});
 503         }
 504         this.conn = new WebSocket(url + "/?sid=" + this.myid + "&page=" + variant);
 505         const socketOpenListener = () => {
 506             if (continuation)
 507             {
 508                 const fen = localStorage.getItem("fen");
 509                 const mycolor = localStorage.getItem("mycolor");
 510                 const oppid = localStorage.getItem("oppid");
 511                 const moves = JSON.parse(localStorage.getItem("moves"));
 512                 this.newGame("human", fen, mycolor, oppid, moves, true);
 513                 // Send ping to server (answer pong if opponent is connected)
 514                 this.conn.send(JSON.stringify({code:"ping",oppid:this.oppid}));
 515             }
 516             else if (localStorage.getItem("newgame") === variant)
 517             {
 518                 // New game request has been cancelled on disconnect
 519                 this.seek = true;
 520                 this.newGame("human", undefined, undefined, undefined, undefined, "reconnect");
 521             }
 522         };
 523         const socketMessageListener = msg => {
 524             const data = JSON.parse(msg.data);
 525             switch (data.code)
 526             {
 527                 case "newgame": //opponent found
 528                     this.newGame("human", data.fen, data.color, data.oppid); //oppid: opponent socket ID
 529                     break;
 530                 case "newmove": //..he played!
 531                     this.play(data.move, "animate");
 532                     break;
 533                 case "pong": //received if we sent a ping (game still alive on our side)
 534                     this.oppConnected = true;
 535                     const L = this.vr.moves.length;
 536                     // Send our "last state" informations to opponent
 537                     this.conn.send(JSON.stringify({
 538                         code:"lastate",
 539                         oppid:this.oppid,
 540                         lastMove:L>0?this.vr.moves[L-1]:undefined,
 541                         movesCount:L,
 542                     }));
 543                     break;
 544                 case "lastate": //got opponent infos about last move (we might have resigned)
 545                     if (this.mode!="human" || this.oppid!=data.oppid)
 546                     {
 547                         // OK, we resigned
 548                         this.conn.send(JSON.stringify({
 549                             code:"lastate",
 550                             oppid:this.oppid,
 551                             lastMove:undefined,
 552                             movesCount:-1,
 553                         }));
 554                     }
 555                     else if (data.movesCount < 0)
 556                     {
 557                         // OK, he resigned
 558                         this.endGame(this.mycolor=="w"?"1-0":"0-1");
 559                     }
 560                     else if (data.movesCount < this.vr.moves.length)
 561                     {
 562                         // We must tell last move to opponent
 563                         const L = this.vr.moves.length;
 564                         this.conn.send(JSON.stringify({
 565                             code:"lastate",
 566                             oppid:this.oppid,
 567                             lastMove:this.vr.moves[L-1],
 568                             movesCount:L,
 569                         }));
 570                     }
 571                     else if (data.movesCount > this.vr.moves.length) //just got last move from him
 572                         this.play(data.lastMove, "animate");
 573                     break;
 574                 case "resign": //..you won!
 575                     this.endGame(this.mycolor=="w"?"1-0":"0-1");
 576                     break;
 577                 // TODO: also use (dis)connect info to count online players?
 578                 case "connect":
 579                 case "disconnect":
 580                     if (this.mode == "human" && this.oppid == data.id)
 581                         this.oppConnected = (data.code == "connect");
 582                     break;
 583             }
 584         };
 585         const socketCloseListener = () => {
 586             this.conn = new WebSocket(url + "/?sid=" + this.myid + "&page=" + variant);
 587             this.conn.addEventListener('open', socketOpenListener);
 588             this.conn.addEventListener('message', socketMessageListener);
 589             this.conn.addEventListener('close', socketCloseListener);
 590         };
 591         this.conn.onopen = socketOpenListener;
 592         this.conn.onmessage = socketMessageListener;
 593         this.conn.onclose = socketCloseListener;
 594         // Listen to keyboard left/right to navigate in game
 595         document.onkeydown = event => {
 596             if (this.mode == "idle" && this.vr.moves.length > 0
 597                 && [37,39].includes(event.keyCode))
 598             {
 599                 event.preventDefault();
 600                 if (event.keyCode == 37) //Back
 601                     this.undo();
 602                 else //Forward (39)
 603                     this.play();
 604             }
 605         };
 606     },
 607     methods: {
 608         download: function() {
 609             let content = document.getElementById("pgn-game").innerHTML;
 610             content = content.replace(/<br>/g, "\n");
 611             // Prepare and trigger download link
 612             let downloadAnchor = document.getElementById("download");
 613             downloadAnchor.setAttribute("download", "game.pgn");
 614             downloadAnchor.href = "data:text/plain;charset=utf-8," + encodeURIComponent(content);
 615             downloadAnchor.click();
 616         },
 617         endGame: function(score) {
 618             this.score = score;
 619             let modalBox = document.getElementById("modal-eog");
 620             modalBox.checked = true;
 621             // Variants may have special PGN structure (so next function isn't defined here)
 622             this.pgnTxt = this.vr.getPGN(this.mycolor, this.score, this.fenStart, this.mode);
 623             setTimeout(() => { modalBox.checked = false; }, 2000);
 624             if (this.mode == "human")
 625                 this.clearStorage();
 626             this.mode = "idle";
 627             this.cursor = this.vr.moves.length; //to navigate in finished game
 628             this.oppid = "";
 629         },
 630         getEndgameMessage: function(score) {
 631             let eogMessage = "Unfinished";
 632             switch (this.score)
 633             {
 634                 case "1-0":
 635                     eogMessage = "White win";
 636                     break;
 637                 case "0-1":
 638                     eogMessage = "Black win";
 639                     break;
 640                 case "1/2":
 641                     eogMessage = "Draw";
 642                     break;
 643             }
 644             return eogMessage;
 645         },
 646         toggleExpertMode: function() {
 647             this.expert = !this.expert;
 648             document.cookie = "expert=" + (this.expert ? "1" : "0");
 649         },
 650         resign: function() {
 651             if (this.mode == "human" && this.oppConnected)
 652             {
 653                 try {
 654                     this.conn.send(JSON.stringify({code: "resign", oppid: this.oppid}));
 655                 } catch (INVALID_STATE_ERR) {
 656                     return; //socket is not ready (and not yet reconnected)
 657                 }
 658             }
 659             this.endGame(this.mycolor=="w"?"0-1":"1-0");
 660         },
 661         setStorage: function() {
 662             localStorage.setItem("myid", this.myid);
 663             localStorage.setItem("variant", variant);
 664             localStorage.setItem("mycolor", this.mycolor);
 665             localStorage.setItem("oppid", this.oppid);
 666             localStorage.setItem("fenStart", this.fenStart);
 667             localStorage.setItem("moves", JSON.stringify(this.vr.moves));
 668             localStorage.setItem("fen", this.vr.getFen());
 669         },
 670         updateStorage: function() {
 671             localStorage.setItem("moves", JSON.stringify(this.vr.moves));
 672             localStorage.setItem("fen", this.vr.getFen());
 673         },
 674         clearStorage: function() {
 675             delete localStorage["variant"];
 676             delete localStorage["myid"];
 677             delete localStorage["mycolor"];
 678             delete localStorage["oppid"];
 679             delete localStorage["fenStart"];
 680             delete localStorage["fen"];
 681             delete localStorage["moves"];
 682         },
 683         clickGameSeek: function() {
 684             if (this.mode == "human")
 685                 return; //no newgame while playing
 686             if (this.seek)
 687             {
 688                 delete localStorage["newgame"]; //cancel game seek
 689                 this.seek = false;
 690             }
 691             else
 692                 this.newGame("human");
 693         },
 694         clickComputerGame: function() {
 695             if (this.mode == "human")
 696                 return; //no newgame while playing
 697             this.newGame("computer");
 698         },
 699         newGame: function(mode, fenInit, color, oppId, moves, continuation) {
 700             const fen = fenInit || VariantRules.GenRandInitFen();
 701             console.log(fen); //DEBUG
 702             this.score = "*";
 703             if (mode=="human" && !oppId)
 704             {
 705                 const storageVariant = localStorage.getItem("variant");
 706                 if (!!storageVariant && storageVariant !== variant)
 707                 {
 708                     alert("Finish your " + storageVariant + " game first!");
 709                     return;
 710                 }
 711                 // Send game request and wait..
 712                 localStorage["newgame"] = variant;
 713                 this.seek = true;
 714                 this.clearStorage(); //in case of
 715                 try {
 716                     this.conn.send(JSON.stringify({code:"newgame", fen:fen}));
 717                 } catch (INVALID_STATE_ERR) {
 718                     return; //nothing achieved
 719                 }
 720                 if (continuation !== "reconnect") //TODO: bad HACK...
 721                 {
 722                     let modalBox = document.getElementById("modal-newgame");
 723                     modalBox.checked = true;
 724                     setTimeout(() => { modalBox.checked = false; }, 2000);
 725                 }
 726                 return;
 727             }
 728             // random enough (TODO: function)
 729             this.gameId = (Date.now().toString(36) + Math.random().toString(36).substr(2, 7)).toUpperCase();
 730             this.vr = new VariantRules(fen, moves || []);
 731             this.pgnTxt = ""; //redundant with this.score = "*", but cleaner
 732             this.mode = mode;
 733             this.incheck = []; //in case of
 734             this.fenStart = continuation
 735                 ? localStorage.getItem("fenStart")
 736                 : fen.split(" ")[0]; //Only the position matters
 737             if (mode=="human")
 738             {
 739                 // Opponent found!
 740                 if (!continuation)
 741                 {
 742                     // Not playing sound on game continuation:
 743                     new Audio("/sounds/newgame.mp3").play().then(() => {}).catch(err => {});
 744                     document.getElementById("modal-newgame").checked = false;
 745                 }
 746                 this.oppid = oppId;
 747                 this.oppConnected = true;
 748                 this.mycolor = color;
 749                 this.seek = false;
 750                 if (!!moves && moves.length > 0) //imply continuation
 751                 {
 752                     const lastMove = moves[moves.length-1];
 753                     this.vr.undo(lastMove);
 754                     this.incheck = this.vr.getCheckSquares(lastMove);
 755                     this.vr.play(lastMove, "ingame");
 756                 }
 757                 delete localStorage["newgame"];
 758                 this.setStorage(); //in case of interruptions
 759             }
 760             else //against computer
 761             {
 762                 this.mycolor = Math.random() < 0.5 ? 'w' : 'b';
 763                 if (this.mycolor == 'b')
 764                     setTimeout(this.playComputerMove, 500);
 765             }
 766         },
 767         playComputerMove: function() {
 768             const timeStart = Date.now();
 769             const nbMoves = this.vr.moves.length; //using played moves to know if search finished
 770             const gameId = this.gameId; //to know if game was reset before timer end
 771             setTimeout(
 772                 () => {
 773                     if (gameId != this.gameId)
 774                         return; //game stopped
 775                     const L = this.vr.moves.length;
 776                     if (nbMoves == L || !this.vr.moves[L-1].notation) //move search didn't finish
 777                         this.vr.shouldReturn = true;
 778                 }, 5000);
 779             const compMove = this.vr.getComputerMove();
 780             // (first move) HACK: avoid selecting elements before they appear on page:
 781             const delay = Math.max(500-(Date.now()-timeStart), 0);
 782             setTimeout(() => this.play(compMove, "animate"), delay);
 783         },
 784         // Get the identifier of a HTML table cell from its numeric coordinates o.x,o.y.
 785         getSquareId: function(o) {
 786             // NOTE: a separator is required to allow any size of board
 787             return  "sq-" + o.x + "-" + o.y;
 788         },
 789         // Inverse function
 790         getSquareFromId: function(id) {
 791             let idParts = id.split('-');
 792             return [parseInt(idParts[1]), parseInt(idParts[2])];
 793         },
 794         mousedown: function(e) {
 795             e = e || window.event;
 796             let ingame = false;
 797             let elem = e.target;
 798             while (!ingame && elem !== null)
 799             {
 800                 if (elem.classList.contains("game"))
 801                 {
 802                     ingame = true;
 803                     break;
 804                 }
 805                 elem = elem.parentElement;
 806             }
 807             if (!ingame) //let default behavior (click on button...)
 808                 return;
 809             e.preventDefault(); //disable native drag & drop
 810             if (!this.selectedPiece && e.target.classList.contains("piece"))
 811             {
 812                 // Next few lines to center the piece on mouse cursor
 813                 let rect = e.target.parentNode.getBoundingClientRect();
 814                 this.start = {
 815                     x: rect.x + rect.width/2,
 816                     y: rect.y + rect.width/2,
 817                     id: e.target.parentNode.id
 818                 };
 819                 this.selectedPiece = e.target.cloneNode();
 820                 this.selectedPiece.style.position = "absolute";
 821                 this.selectedPiece.style.top = 0;
 822                 this.selectedPiece.style.display = "inline-block";
 823                 this.selectedPiece.style.zIndex = 3000;
 824                 let startSquare = this.getSquareFromId(e.target.parentNode.id);
 825                 this.possibleMoves = this.mode!="idle" && this.vr.canIplay(this.mycolor,startSquare)
 826                     ? this.vr.getPossibleMovesFrom(startSquare)
 827                     : [];
 828                 // Next line add moving piece just after current image (required for Crazyhouse reserve)
 829                 e.target.parentNode.insertBefore(this.selectedPiece, e.target.nextSibling);
 830             }
 831         },
 832         mousemove: function(e) {
 833             if (!this.selectedPiece)
 834                 return;
 835             e = e || window.event;
 836             // If there is an active element, move it around
 837             if (!!this.selectedPiece)
 838             {
 839                 const [offsetX,offsetY] = !!e.clientX
 840                     ? [e.clientX,e.clientY] //desktop browser
 841                     : [e.changedTouches[0].pageX, e.changedTouches[0].pageY]; //smartphone
 842                 this.selectedPiece.style.left = (offsetX-this.start.x) + "px";
 843                 this.selectedPiece.style.top = (offsetY-this.start.y) + "px";
 844             }
 845         },
 846         mouseup: function(e) {
 847             if (!this.selectedPiece)
 848                 return;
 849             e = e || window.event;
 850             // Read drop target (or parentElement, parentNode... if type == "img")
 851             this.selectedPiece.style.zIndex = -3000; //HACK to find square from final coordinates
 852             const [offsetX,offsetY] = !!e.clientX
 853                 ? [e.clientX,e.clientY]
 854                 : [e.changedTouches[0].pageX, e.changedTouches[0].pageY];
 855             let landing = document.elementFromPoint(offsetX, offsetY);
 856             this.selectedPiece.style.zIndex = 3000;
 857             while (landing.tagName == "IMG") //classList.contains(piece) fails because of mark/highlight
 858                 landing = landing.parentNode;
 859             if (this.start.id == landing.id) //a click: selectedPiece and possibleMoves already filled
 860                 return;
 861             // OK: process move attempt
 862             let endSquare = this.getSquareFromId(landing.id);
 863             let moves = this.findMatchingMoves(endSquare);
 864             this.possibleMoves = [];
 865             if (moves.length > 1)
 866                 this.choices = moves;
 867             else if (moves.length==1)
 868                 this.play(moves[0]);
 869             // Else: impossible move
 870             this.selectedPiece.parentNode.removeChild(this.selectedPiece);
 871             delete this.selectedPiece;
 872             this.selectedPiece = null;
 873         },
 874         findMatchingMoves: function(endSquare) {
 875             // Run through moves list and return the matching set (if promotions...)
 876             let moves = [];
 877             this.possibleMoves.forEach(function(m) {
 878                 if (endSquare[0] == m.end.x && endSquare[1] == m.end.y)
 879                     moves.push(m);
 880             });
 881             return moves;
 882         },
 883         animateMove: function(move) {
 884             let startSquare = document.getElementById(this.getSquareId(move.start));
 885             let endSquare = document.getElementById(this.getSquareId(move.end));
 886             let rectStart = startSquare.getBoundingClientRect();
 887             let rectEnd = endSquare.getBoundingClientRect();
 888             let translation = {x:rectEnd.x-rectStart.x, y:rectEnd.y-rectStart.y};
 889             let movingPiece =
 890                 document.querySelector("#" + this.getSquareId(move.start) + " > img.piece");
 891             // HACK for animation (with positive translate, image slides "under background"...)
 892             // Possible improvement: just alter squares on the piece's way...
 893             squares = document.getElementsByClassName("board");
 894             for (let i=0; i<squares.length; i++)
 895             {
 896                 let square = squares.item(i);
 897                 if (square.id != this.getSquareId(move.start))
 898                     square.style.zIndex = "-1";
 899             }
 900             movingPiece.style.transform = "translate(" + translation.x + "px," + translation.y + "px)";
 901             movingPiece.style.transitionDuration = "0.2s";
 902             movingPiece.style.zIndex = "3000";
 903             setTimeout( () => {
 904                 for (let i=0; i<squares.length; i++)
 905                     squares.item(i).style.zIndex = "auto";
 906                 movingPiece.style = {}; //required e.g. for 0-0 with KR swap
 907                 this.play(move);
 908             }, 200);
 909         },
 910         play: function(move, programmatic) {
 911             if (!move)
 912             {
 913                 // Navigate after game is over
 914                 if (this.cursor >= this.vr.moves.length)
 915                     return; //already at the end
 916                 move = this.vr.moves[this.cursor++];
 917             }
 918             if (!!programmatic) //computer or human opponent
 919             {
 920                 this.animateMove(move);
 921                 return;
 922             }
 923             // Not programmatic, or animation is over
 924             if (this.mode == "human" && this.vr.turn == this.mycolor)
 925                 this.conn.send(JSON.stringify({code:"newmove", move:move, oppid:this.oppid}));
 926             new Audio("/sounds/chessmove1.mp3").play().then(() => {}).catch(err => {});
 927             if (this.mode != "idle")
 928             {
 929                 this.incheck = this.vr.getCheckSquares(move); //is opponent in check?
 930                 this.vr.play(move, "ingame");
 931             }
 932             else
 933             {
 934                 VariantRules.PlayOnBoard(this.vr.board, move);
 935                 this.$forceUpdate(); //TODO: ?!
 936             }
 937             if (this.mode == "human")
 938                 this.updateStorage(); //after our moves and opponent moves
 939             if (this.mode != "idle")
 940             {
 941                 const eog = this.vr.checkGameOver();
 942                 if (eog != "*")
 943                     this.endGame(eog);
 944             }
 945             if (this.mode == "computer" && this.vr.turn != this.mycolor)
 946                 setTimeout(this.playComputerMove, 500);
 947         },
 948         undo: function() {
 949             // Navigate after game is over
 950             if (this.cursor == 0)
 951                 return; //already at the beginning
 952             if (this.cursor == this.vr.moves.length)
 953                 this.incheck = []; //in case of...
 954             const move = this.vr.moves[--this.cursor];
 955             VariantRules.UndoOnBoard(this.vr.board, move);
 956             this.$forceUpdate(); //TODO: ?!
 957         }
 958     },
 959 })