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: getCookie("expert") === "1" ? true : 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                         },
 253                         [h('i', { 'class': { "material-icons": true } }, "fast_rewind")]),
 254                     h('button',
 255                         {
 256                             on: { click: e => this.play() },
 257                             attrs: { "aria-label": 'Play' },
 258                         },
 259                         [h('i', { 'class': { "material-icons": true } }, "fast_forward")]),
 260                     ]
 261                 );
 262             }
 263             elementArray.push(gameDiv);
 264             if (!!this.vr.reserve)
 265             {
 266                 const shiftIdx = (this.mycolor=="w" ? 0 : 1);
 267                 let myReservePiecesArray = [];
 268                 for (let i=0; i<VariantRules.RESERVE_PIECES.length; i++)
 269                 {
 270                     myReservePiecesArray.push(h('div',
 271                     {
 272                         'class': {'board':true, ['board'+sizeY]:true},
 273                         attrs: { id: this.getSquareId({x:sizeX+shiftIdx,y:i}) }
 274                     },
 275                     [
 276                         h('img',
 277                         {
 278                             'class': {"piece":true},
 279                             attrs: {
 280                                 "src": "/images/pieces/" +
 281                                     this.vr.getReservePpath(this.mycolor,i) + ".svg",
 282                             }
 283                         }),
 284                         h('sup',
 285                             {style: { "padding-left":"40%"} },
 286                             [ this.vr.reserve[this.mycolor][VariantRules.RESERVE_PIECES[i]] ]
 287                         )
 288                     ]));
 289                 }
 290                 let oppReservePiecesArray = [];
 291                 const oppCol = this.vr.getOppCol(this.mycolor);
 292                 for (let i=0; i<VariantRules.RESERVE_PIECES.length; i++)
 293                 {
 294                     oppReservePiecesArray.push(h('div',
 295                     {
 296                         'class': {'board':true, ['board'+sizeY]:true},
 297                         attrs: { id: this.getSquareId({x:sizeX+(1-shiftIdx),y:i}) }
 298                     },
 299                     [
 300                         h('img',
 301                         {
 302                             'class': {"piece":true},
 303                             attrs: {
 304                                 "src": "/images/pieces/" +
 305                                     this.vr.getReservePpath(oppCol,i) + ".svg",
 306                             }
 307                         }),
 308                         h('sup',
 309                             {style: { "padding-left":"40%"} },
 310                             [ this.vr.reserve[oppCol][VariantRules.RESERVE_PIECES[i]] ]
 311                         )
 312                     ]));
 313                 }
 314                 let reserves = h('div',
 315                     {
 316                         'class':{'game':true},
 317                         style: {"margin-bottom": "20px"},
 318                     },
 319                     [
 320                         h('div',
 321                             {
 322                                 'class': { 'row': true },
 323                                 style: {"margin-bottom": "15px"},
 324                             },
 325                             myReservePiecesArray
 326                         ),
 327                         h('div',
 328                             { 'class': { 'row': true }},
 329                             oppReservePiecesArray
 330                         )
 331                     ]
 332                 );
 333                 elementArray.push(reserves);
 334             }
 335             const eogMessage = this.getEndgameMessage(this.score);
 336             const modalEog = [
 337                 h('input',
 338                     {
 339                         attrs: { "id": "modal-eog", type: "checkbox" },
 340                         "class": { "modal": true },
 341                     }),
 342                 h('div',
 343                     {
 344                         attrs: { "role": "dialog", "aria-labelledby": "modal-eog" },
 345                     },
 346                     [
 347                         h('div',
 348                             {
 349                                 "class": { "card": true, "smallpad": true },
 350                             },
 351                             [
 352                                 h('label',
 353                                     {
 354                                         attrs: { "for": "modal-eog" },
 355                                         "class": { "modal-close": true },
 356                                     }
 357                                 ),
 358                                 h('h3',
 359                                     {
 360                                         "class": { "section": true },
 361                                         domProps: { innerHTML: eogMessage },
 362                                     }
 363                                 )
 364                             ]
 365                         )
 366                     ]
 367                 )
 368             ];
 369             elementArray = elementArray.concat(modalEog);
 370         }
 371         const modalNewgame = [
 372             h('input',
 373                 {
 374                     attrs: { "id": "modal-newgame", type: "checkbox" },
 375                     "class": { "modal": true },
 376                 }),
 377             h('div',
 378                 {
 379                     attrs: { "role": "dialog", "aria-labelledby": "modal-newgame" },
 380                 },
 381                 [
 382                     h('div',
 383                         {
 384                             "class": { "card": true, "smallpad": true },
 385                         },
 386                         [
 387                             h('label',
 388                                 {
 389                                     attrs: { "id": "close-newgame", "for": "modal-newgame" },
 390                                     "class": { "modal-close": true },
 391                                 }
 392                             ),
 393                             h('h3',
 394                                 {
 395                                     "class": { "section": true },
 396                                     domProps: { innerHTML: "New game" },
 397                                 }
 398                             ),
 399                             h('p',
 400                                 {
 401                                     "class": { "section": true },
 402                                     domProps: { innerHTML: "Waiting for opponent..." },
 403                                 }
 404                             )
 405                         ]
 406                     )
 407                 ]
 408             )
 409         ];
 410         elementArray = elementArray.concat(modalNewgame);
 411         const actions = h('div',
 412             {
 413                 attrs: { "id": "actions" },
 414                 'class': { 'text-center': true },
 415             },
 416             actionArray
 417         );
 418         elementArray.push(actions);
 419         if (this.score != "*")
 420         {
 421             elementArray.push(
 422                 h('div',
 423                     { attrs: { id: "pgn-div" } },
 424                     [
 425                         h('a',
 426                             {
 427                                 attrs: {
 428                                     id: "download",
 429                                     href: "#",
 430                                 }
 431                             }
 432                         ),
 433                         h('p',
 434                             {
 435                                 attrs: { id: "pgn-game" },
 436                                 on: { click: this.download },
 437                                 domProps: { innerHTML: this.pgnTxt }
 438                             }
 439                         )
 440                     ]
 441                 )
 442             );
 443         }
 444         else if (this.mode != "idle")
 445         {
 446             // Show current FEN (at least for debug)
 447             elementArray.push(
 448                 h('div',
 449                     { attrs: { id: "fen-div" } },
 450                     [
 451                         h('p',
 452                             {
 453                                 attrs: { id: "fen-string" },
 454                                 domProps: { innerHTML: this.vr.getBaseFen() }
 455                             }
 456                         )
 457                     ]
 458                 )
 459             );
 460         }
 461         return h(
 462             'div',
 463             {
 464                 'class': {
 465                     "col-sm-12":true,
 466                     "col-md-8":true,
 467                     "col-md-offset-2":true,
 468                     "col-lg-6":true,
 469                     "col-lg-offset-3":true,
 470                 },
 471                 // NOTE: click = mousedown + mouseup
 472                 on: {
 473                     mousedown: this.mousedown,
 474                     mousemove: this.mousemove,
 475                     mouseup: this.mouseup,
 476                     touchstart: this.mousedown,
 477                     touchmove: this.mousemove,
 478                     touchend: this.mouseup,
 479                 },
 480             },
 481             elementArray
 482         );
 483     },
 484     created: function() {
 485         const url = socketUrl;
 486         const continuation = (localStorage.getItem("variant") === variant);
 487         this.myid = continuation ? localStorage.getItem("myid") : getRandString();
 488         if (!continuation)
 489         {
 490             // HACK: play a small silent sound to allow "new game" sound later if tab not focused
 491             new Audio("/sounds/silent.mp3").play().then(() => {}).catch(err => {});
 492         }
 493         this.conn = new WebSocket(url + "/?sid=" + this.myid + "&page=" + variant);
 494         const socketOpenListener = () => {
 495             if (continuation)
 496             {
 497                 const fen = localStorage.getItem("fen");
 498                 const mycolor = localStorage.getItem("mycolor");
 499                 const oppid = localStorage.getItem("oppid");
 500                 const moves = JSON.parse(localStorage.getItem("moves"));
 501                 this.newGame("human", fen, mycolor, oppid, moves, true);
 502                 // Send ping to server (answer pong if opponent is connected)
 503                 this.conn.send(JSON.stringify({code:"ping",oppid:this.oppid}));
 504             }
 505             else if (localStorage.getItem("newgame") === variant)
 506             {
 507                 // New game request has been cancelled on disconnect
 508                 this.newGame("human", undefined, undefined, undefined, undefined, "reconnect");
 509             }
 510         };
 511         const socketMessageListener = msg => {
 512             const data = JSON.parse(msg.data);
 513             switch (data.code)
 514             {
 515                 case "newgame": //opponent found
 516                     this.newGame("human", data.fen, data.color, data.oppid); //oppid: opponent socket ID
 517                     break;
 518                 case "newmove": //..he played!
 519                     this.play(data.move, "animate");
 520                     break;
 521                 case "pong": //received if we sent a ping (game still alive on our side)
 522                     this.oppConnected = true;
 523                     const L = this.vr.moves.length;
 524                     // Send our "last state" informations to opponent
 525                     this.conn.send(JSON.stringify({
 526                         code:"lastate",
 527                         oppid:this.oppid,
 528                         lastMove:L>0?this.vr.moves[L-1]:undefined,
 529                         movesCount:L,
 530                     }));
 531                     break;
 532                 case "lastate": //got opponent infos about last move (we might have resigned)
 533                     if (this.mode!="human" || this.oppid!=data.oppid)
 534                     {
 535                         // OK, we resigned
 536                         this.conn.send(JSON.stringify({
 537                             code:"lastate",
 538                             oppid:this.oppid,
 539                             lastMove:undefined,
 540                             movesCount:-1,
 541                         }));
 542                     }
 543                     else if (data.movesCount < 0)
 544                     {
 545                         // OK, he resigned
 546                         this.endGame(this.mycolor=="w"?"1-0":"0-1");
 547                     }
 548                     else if (data.movesCount < this.vr.moves.length)
 549                     {
 550                         // We must tell last move to opponent
 551                         const L = this.vr.moves.length;
 552                         this.conn.send(JSON.stringify({
 553                             code:"lastate",
 554                             oppid:this.oppid,
 555                             lastMove:this.vr.moves[L-1],
 556                             movesCount:L,
 557                         }));
 558                     }
 559                     else if (data.movesCount > this.vr.moves.length) //just got last move from him
 560                         this.play(data.lastMove, "animate");
 561                     break;
 562                 case "resign": //..you won!
 563                     this.endGame(this.mycolor=="w"?"1-0":"0-1");
 564                     break;
 565                 // TODO: also use (dis)connect info to count online players?
 566                 case "connect":
 567                 case "disconnect":
 568                     if (this.mode == "human" && this.oppid == data.id)
 569                         this.oppConnected = (data.code == "connect");
 570                     break;
 571             }
 572         };
 573         const socketCloseListener = () => {
 574             this.conn = new WebSocket(url + "/?sid=" + this.myid + "&page=" + variant);
 575             this.conn.addEventListener('open', socketOpenListener);
 576             this.conn.addEventListener('message', socketMessageListener);
 577             this.conn.addEventListener('close', socketCloseListener);
 578         };
 579         this.conn.onopen = socketOpenListener;
 580         this.conn.onmessage = socketMessageListener;
 581         this.conn.onclose = socketCloseListener;
 582         // Listen to keyboard left/right to navigate in game
 583         document.onkeydown = event => {
 584             if (this.mode == "idle" && this.vr.moves.length > 0
 585                 && [37,39].includes(event.keyCode))
 586             {
 587                 event.preventDefault();
 588                 if (event.keyCode == 37) //Back
 589                     this.undo();
 590                 else //Forward (39)
 591                     this.play();
 592             }
 593         };
 594     },
 595     methods: {
 596         download: function() {
 597             let content = document.getElementById("pgn-game").innerHTML;
 598             content = content.replace(/<br>/g, "\n");
 599             // Prepare and trigger download link
 600             let downloadAnchor = document.getElementById("download");
 601             downloadAnchor.setAttribute("download", "game.pgn");
 602             downloadAnchor.href = "data:text/plain;charset=utf-8," + encodeURIComponent(content);
 603             downloadAnchor.click();
 604         },
 605         endGame: function(score) {
 606             this.score = score;
 607             let modalBox = document.getElementById("modal-eog");
 608             modalBox.checked = true;
 609             // Variants may have special PGN structure (so next function isn't defined here)
 610             this.pgnTxt = this.vr.getPGN(this.mycolor, this.score, this.fenStart, this.mode);
 611             setTimeout(() => { modalBox.checked = false; }, 2000);
 612             if (this.mode == "human")
 613                 this.clearStorage();
 614             this.mode = "idle";
 615             this.cursor = this.vr.moves.length; //to navigate in finished game
 616             this.oppid = "";
 617         },
 618         getEndgameMessage: function(score) {
 619             let eogMessage = "Unfinished";
 620             switch (this.score)
 621             {
 622                 case "1-0":
 623                     eogMessage = "White win";
 624                     break;
 625                 case "0-1":
 626                     eogMessage = "Black win";
 627                     break;
 628                 case "1/2":
 629                     eogMessage = "Draw";
 630                     break;
 631             }
 632             return eogMessage;
 633         },
 634         setStorage: function() {
 635             localStorage.setItem("myid", this.myid);
 636             localStorage.setItem("variant", variant);
 637             localStorage.setItem("mycolor", this.mycolor);
 638             localStorage.setItem("oppid", this.oppid);
 639             localStorage.setItem("fenStart", this.fenStart);
 640             localStorage.setItem("moves", JSON.stringify(this.vr.moves));
 641             localStorage.setItem("fen", this.vr.getFen());
 642         },
 643         updateStorage: function() {
 644             localStorage.setItem("moves", JSON.stringify(this.vr.moves));
 645             localStorage.setItem("fen", this.vr.getFen());
 646         },
 647         clearStorage: function() {
 648             delete localStorage["variant"];
 649             delete localStorage["myid"];
 650             delete localStorage["mycolor"];
 651             delete localStorage["oppid"];
 652             delete localStorage["fenStart"];
 653             delete localStorage["fen"];
 654             delete localStorage["moves"];
 655         },
 656         // HACK because mini-css tooltips are persistent after click...
 657         getRidOfTooltip: function(elt) {
 658             elt.style.visibility = "hidden";
 659             setTimeout(() => { elt.style.visibility="visible"; }, 100);
 660         },
 661         clickGameSeek: function(e) {
 662             this.getRidOfTooltip(e.currentTarget);
 663             if (this.mode == "human")
 664                 return; //no newgame while playing
 665             if (this.seek)
 666             {
 667                 this.conn.send(JSON.stringify({code:"cancelnewgame"}));
 668                 delete localStorage["newgame"]; //cancel game seek
 669                 this.seek = false;
 670             }
 671             else
 672                 this.newGame("human");
 673         },
 674         clickComputerGame: function(e) {
 675             this.getRidOfTooltip(e.currentTarget);
 676             if (this.mode == "human")
 677                 return; //no newgame while playing
 678             this.newGame("computer");
 679         },
 680         toggleExpertMode: function(e) {
 681             this.getRidOfTooltip(e.currentTarget);
 682             this.expert = !this.expert;
 683             setCookie("expert", this.expert ? "1" : "0");
 684         },
 685         resign: function() {
 686             if (this.mode == "human" && this.oppConnected)
 687             {
 688                 try {
 689                     this.conn.send(JSON.stringify({code: "resign", oppid: this.oppid}));
 690                 } catch (INVALID_STATE_ERR) {
 691                     return; //socket is not ready (and not yet reconnected)
 692                 }
 693             }
 694             this.endGame(this.mycolor=="w"?"0-1":"1-0");
 695         },
 696         newGame: function(mode, fenInit, color, oppId, moves, continuation) {
 697             const fen = fenInit || VariantRules.GenRandInitFen();
 698             console.log(fen); //DEBUG
 699             if (mode=="human" && !oppId)
 700             {
 701                 const storageVariant = localStorage.getItem("variant");
 702                 if (!!storageVariant && storageVariant !== variant)
 703                 {
 704                     alert("Finish your " + storageVariant + " game first!");
 705                     return;
 706                 }
 707                 // Send game request and wait..
 708                 localStorage["newgame"] = variant;
 709                 this.seek = true;
 710                 this.clearStorage(); //in case of
 711                 try {
 712                     this.conn.send(JSON.stringify({code:"newgame", fen:fen}));
 713                 } catch (INVALID_STATE_ERR) {
 714                     return; //nothing achieved
 715                 }
 716                 if (continuation !== "reconnect") //TODO: bad HACK...
 717                 {
 718                     let modalBox = document.getElementById("modal-newgame");
 719                     modalBox.checked = true;
 720                     setTimeout(() => { modalBox.checked = false; }, 2000);
 721                 }
 722                 return;
 723             }
 724             this.gameId = getRandString();
 725             this.vr = new VariantRules(fen, moves || []);
 726             this.score = "*";
 727             this.pgnTxt = ""; //redundant with this.score = "*", but cleaner
 728             this.mode = mode;
 729             this.incheck = []; //in case of
 730             this.fenStart = continuation
 731                 ? localStorage.getItem("fenStart")
 732                 : fen.split(" ")[0]; //Only the position matters
 733             if (mode=="human")
 734             {
 735                 // Opponent found!
 736                 if (!continuation)
 737                 {
 738                     // Not playing sound on game continuation:
 739                     new Audio("/sounds/newgame.mp3").play().then(() => {}).catch(err => {});
 740                     document.getElementById("modal-newgame").checked = false;
 741                 }
 742                 this.oppid = oppId;
 743                 this.oppConnected = true;
 744                 this.mycolor = color;
 745                 this.seek = false;
 746                 if (!!moves && moves.length > 0) //imply continuation
 747                 {
 748                     const lastMove = moves[moves.length-1];
 749                     this.vr.undo(lastMove);
 750                     this.incheck = this.vr.getCheckSquares(lastMove);
 751                     this.vr.play(lastMove, "ingame");
 752                 }
 753                 delete localStorage["newgame"];
 754                 this.setStorage(); //in case of interruptions
 755             }
 756             else //against computer
 757             {
 758                 this.mycolor = Math.random() < 0.5 ? 'w' : 'b';
 759                 if (this.mycolor == 'b')
 760                     setTimeout(this.playComputerMove, 500);
 761             }
 762         },
 763         playComputerMove: function() {
 764             const timeStart = Date.now();
 765             const nbMoves = this.vr.moves.length; //using played moves to know if search finished
 766             const gameId = this.gameId; //to know if game was reset before timer end
 767             setTimeout(
 768                 () => {
 769                     if (gameId != this.gameId)
 770                         return; //game stopped
 771                     const L = this.vr.moves.length;
 772                     if (nbMoves == L || !this.vr.moves[L-1].notation) //move search didn't finish
 773                         this.vr.shouldReturn = true;
 774                 }, 5000);
 775             const compMove = this.vr.getComputerMove();
 776             // (first move) HACK: avoid selecting elements before they appear on page:
 777             const delay = Math.max(500-(Date.now()-timeStart), 0);
 778             setTimeout(() => this.play(compMove, "animate"), delay);
 779         },
 780         // Get the identifier of a HTML table cell from its numeric coordinates o.x,o.y.
 781         getSquareId: function(o) {
 782             // NOTE: a separator is required to allow any size of board
 783             return  "sq-" + o.x + "-" + o.y;
 784         },
 785         // Inverse function
 786         getSquareFromId: function(id) {
 787             let idParts = id.split('-');
 788             return [parseInt(idParts[1]), parseInt(idParts[2])];
 789         },
 790         mousedown: function(e) {
 791             e = e || window.event;
 792             let ingame = false;
 793             let elem = e.target;
 794             while (!ingame && elem !== null)
 795             {
 796                 if (elem.classList.contains("game"))
 797                 {
 798                     ingame = true;
 799                     break;
 800                 }
 801                 elem = elem.parentElement;
 802             }
 803             if (!ingame) //let default behavior (click on button...)
 804                 return;
 805             e.preventDefault(); //disable native drag & drop
 806             if (!this.selectedPiece && e.target.classList.contains("piece"))
 807             {
 808                 // Next few lines to center the piece on mouse cursor
 809                 let rect = e.target.parentNode.getBoundingClientRect();
 810                 this.start = {
 811                     x: rect.x + rect.width/2,
 812                     y: rect.y + rect.width/2,
 813                     id: e.target.parentNode.id
 814                 };
 815                 this.selectedPiece = e.target.cloneNode();
 816                 this.selectedPiece.style.position = "absolute";
 817                 this.selectedPiece.style.top = 0;
 818                 this.selectedPiece.style.display = "inline-block";
 819                 this.selectedPiece.style.zIndex = 3000;
 820                 let startSquare = this.getSquareFromId(e.target.parentNode.id);
 821                 this.possibleMoves = this.mode!="idle" && this.vr.canIplay(this.mycolor,startSquare)
 822                     ? this.vr.getPossibleMovesFrom(startSquare)
 823                     : [];
 824                 // Next line add moving piece just after current image (required for Crazyhouse reserve)
 825                 e.target.parentNode.insertBefore(this.selectedPiece, e.target.nextSibling);
 826             }
 827         },
 828         mousemove: function(e) {
 829             if (!this.selectedPiece)
 830                 return;
 831             e = e || window.event;
 832             // If there is an active element, move it around
 833             if (!!this.selectedPiece)
 834             {
 835                 const [offsetX,offsetY] = !!e.clientX
 836                     ? [e.clientX,e.clientY] //desktop browser
 837                     : [e.changedTouches[0].pageX, e.changedTouches[0].pageY]; //smartphone
 838                 this.selectedPiece.style.left = (offsetX-this.start.x) + "px";
 839                 this.selectedPiece.style.top = (offsetY-this.start.y) + "px";
 840             }
 841         },
 842         mouseup: function(e) {
 843             if (!this.selectedPiece)
 844                 return;
 845             e = e || window.event;
 846             // Read drop target (or parentElement, parentNode... if type == "img")
 847             this.selectedPiece.style.zIndex = -3000; //HACK to find square from final coordinates
 848             const [offsetX,offsetY] = !!e.clientX
 849                 ? [e.clientX,e.clientY]
 850                 : [e.changedTouches[0].pageX, e.changedTouches[0].pageY];
 851             let landing = document.elementFromPoint(offsetX, offsetY);
 852             this.selectedPiece.style.zIndex = 3000;
 853             while (landing.tagName == "IMG") //classList.contains(piece) fails because of mark/highlight
 854                 landing = landing.parentNode;
 855             if (this.start.id == landing.id) //a click: selectedPiece and possibleMoves already filled
 856                 return;
 857             // OK: process move attempt
 858             let endSquare = this.getSquareFromId(landing.id);
 859             let moves = this.findMatchingMoves(endSquare);
 860             this.possibleMoves = [];
 861             if (moves.length > 1)
 862                 this.choices = moves;
 863             else if (moves.length==1)
 864                 this.play(moves[0]);
 865             // Else: impossible move
 866             this.selectedPiece.parentNode.removeChild(this.selectedPiece);
 867             delete this.selectedPiece;
 868             this.selectedPiece = null;
 869         },
 870         findMatchingMoves: function(endSquare) {
 871             // Run through moves list and return the matching set (if promotions...)
 872             let moves = [];
 873             this.possibleMoves.forEach(function(m) {
 874                 if (endSquare[0] == m.end.x && endSquare[1] == m.end.y)
 875                     moves.push(m);
 876             });
 877             return moves;
 878         },
 879         animateMove: function(move) {
 880             let startSquare = document.getElementById(this.getSquareId(move.start));
 881             let endSquare = document.getElementById(this.getSquareId(move.end));
 882             let rectStart = startSquare.getBoundingClientRect();
 883             let rectEnd = endSquare.getBoundingClientRect();
 884             let translation = {x:rectEnd.x-rectStart.x, y:rectEnd.y-rectStart.y};
 885             let movingPiece =
 886                 document.querySelector("#" + this.getSquareId(move.start) + " > img.piece");
 887             // HACK for animation (with positive translate, image slides "under background"...)
 888             // Possible improvement: just alter squares on the piece's way...
 889             squares = document.getElementsByClassName("board");
 890             for (let i=0; i<squares.length; i++)
 891             {
 892                 let square = squares.item(i);
 893                 if (square.id != this.getSquareId(move.start))
 894                     square.style.zIndex = "-1";
 895             }
 896             movingPiece.style.transform = "translate(" + translation.x + "px," + translation.y + "px)";
 897             movingPiece.style.transitionDuration = "0.2s";
 898             movingPiece.style.zIndex = "3000";
 899             setTimeout( () => {
 900                 for (let i=0; i<squares.length; i++)
 901                     squares.item(i).style.zIndex = "auto";
 902                 movingPiece.style = {}; //required e.g. for 0-0 with KR swap
 903                 this.play(move);
 904             }, 200);
 905         },
 906         play: function(move, programmatic) {
 907             if (!move)
 908             {
 909                 // Navigate after game is over
 910                 if (this.cursor >= this.vr.moves.length)
 911                     return; //already at the end
 912                 move = this.vr.moves[this.cursor++];
 913             }
 914             if (!!programmatic) //computer or human opponent
 915             {
 916                 this.animateMove(move);
 917                 return;
 918             }
 919             // Not programmatic, or animation is over
 920             if (this.mode == "human" && this.vr.turn == this.mycolor)
 921                 this.conn.send(JSON.stringify({code:"newmove", move:move, oppid:this.oppid}));
 922             new Audio("/sounds/chessmove1.mp3").play().then(() => {}).catch(err => {});
 923             if (this.mode != "idle")
 924             {
 925                 this.incheck = this.vr.getCheckSquares(move); //is opponent in check?
 926                 this.vr.play(move, "ingame");
 927             }
 928             else
 929             {
 930                 VariantRules.PlayOnBoard(this.vr.board, move);
 931                 this.$forceUpdate(); //TODO: ?!
 932             }
 933             if (this.mode == "human")
 934                 this.updateStorage(); //after our moves and opponent moves
 935             if (this.mode != "idle")
 936             {
 937                 const eog = this.vr.checkGameOver();
 938                 if (eog != "*")
 939                     this.endGame(eog);
 940             }
 941             if (this.mode == "computer" && this.vr.turn != this.mycolor)
 942                 setTimeout(this.playComputerMove, 500);
 943         },
 944         undo: function() {
 945             // Navigate after game is over
 946             if (this.cursor == 0)
 947                 return; //already at the beginning
 948             if (this.cursor == this.vr.moves.length)
 949                 this.incheck = []; //in case of...
 950             const move = this.vr.moves[--this.cursor];
 951             VariantRules.UndoOnBoard(this.vr.board, move);
 952             this.$forceUpdate(); //TODO: ?!
 953         }
 954     },
 955 })