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 highlight = !!lm && _.isMatch(lm.end, {x:ci,y:cj});
 206                             return h(
 207                                 'div',
 208                                 {
 209                                     'class': {
 210                                         'board': true,
 211                                         ['board'+sizeY]: true,
 212                                         'light-square': (i+j)%2==0 && (this.expert || !highlight),
 213                                         'dark-square': (i+j)%2==1 && (this.expert || !highlight),
 214                                         'highlight': !this.expert && highlight,
 215                                         'incheck': !this.expert && incheckSq[ci][cj],
 216                                     },
 217                                     attrs: {
 218                                         id: this.getSquareId({x:ci,y:cj}),
 219                                     },
 220                                 },
 221                                 elems
 222                             );
 223                         })
 224                     );
 225                 }), choices]
 226             );
 227             if (this.mode != "idle")
 228             {
 229                 actionArray.push(
 230                     h('button',
 231                         {
 232                             on: { click: this.resign },
 233                             attrs: { "aria-label": 'Resign' },
 234                             'class': {
 235                                 "tooltip":true,
 236                                 "bottom": true,
 237                             },
 238                         },
 239                         [h('i', { 'class': { "material-icons": true } }, "flag")])
 240                 );
 241             }
 242             elementArray.push(gameDiv);
 243             if (!!this.vr.reserve)
 244             {
 245                 let myReservePiecesArray = [];
 246                 for (let i=0; i<VariantRules.RESERVE_PIECES.length; i++)
 247                 {
 248                     myReservePiecesArray.push(h('div',
 249                     {
 250                         'class': {'board':true, ['board'+sizeY]:true},
 251                         attrs: { id: this.getSquareId({x:sizeX,y:i}) }
 252                     },
 253                     [
 254                         h('img',
 255                         {
 256                             'class': {"piece":true},
 257                             attrs: {
 258                                 "src": "/images/pieces/" +
 259                                     this.vr.getReservePpath(this.mycolor,i) + ".svg",
 260                             }
 261                         }),
 262                         h('sup',
 263                             {style: { "padding-left":"40%"} },
 264                             [ this.vr.reserve[this.mycolor][VariantRules.RESERVE_PIECES[i]] ]
 265                         )
 266                     ]));
 267                 }
 268                 let oppReservePiecesArray = [];
 269                 const oppCol = this.vr.getOppCol(this.mycolor);
 270                 for (let i=0; i<VariantRules.RESERVE_PIECES.length; i++)
 271                 {
 272                     oppReservePiecesArray.push(h('div',
 273                     {
 274                         'class': {'board':true, ['board'+sizeY]:true},
 275                         attrs: { id: this.getSquareId({x:sizeX,y:i}) }
 276                     },
 277                     [
 278                         h('img',
 279                         {
 280                             'class': {"piece":true},
 281                             attrs: {
 282                                 "src": "/images/pieces/" +
 283                                     this.vr.getReservePpath(oppCol,i) + ".svg",
 284                             }
 285                         }),
 286                         h('sup',
 287                             {style: { "padding-left":"40%"} },
 288                             [ this.vr.reserve[oppCol][VariantRules.RESERVE_PIECES[i]] ]
 289                         )
 290                     ]));
 291                 }
 292                 let reserves = h('div',
 293                     {
 294                         'class':{'game':true},
 295                         style: {"margin-bottom": "20px"},
 296                     },
 297                     [
 298                         h('div',
 299                             {
 300                                 'class': { 'row': true },
 301                                 style: {"margin-bottom": "15px"},
 302                             },
 303                             myReservePiecesArray
 304                         ),
 305                         h('div',
 306                             { 'class': { 'row': true }},
 307                             oppReservePiecesArray
 308                         )
 309                     ]
 310                 );
 311                 elementArray.push(reserves);
 312             }
 313             const eogMessage = this.getEndgameMessage(this.score);
 314             const modalEog = [
 315                 h('input',
 316                     {
 317                         attrs: { "id": "modal-eog", type: "checkbox" },
 318                         "class": { "modal": true },
 319                     }),
 320                 h('div',
 321                     {
 322                         attrs: { "role": "dialog", "aria-labelledby": "dialog-title" },
 323                     },
 324                     [
 325                         h('div',
 326                             {
 327                                 "class": { "card": true, "smallpad": true },
 328                             },
 329                             [
 330                                 h('label',
 331                                     {
 332                                         attrs: { "for": "modal-eog" },
 333                                         "class": { "modal-close": true },
 334                                     }
 335                                 ),
 336                                 h('h3',
 337                                     {
 338                                         "class": { "section": true },
 339                                         domProps: { innerHTML: eogMessage },
 340                                     }
 341                                 )
 342                             ]
 343                         )
 344                     ]
 345                 )
 346             ];
 347             elementArray = elementArray.concat(modalEog);
 348         }
 349         const modalNewgame = [
 350             h('input',
 351                 {
 352                     attrs: { "id": "modal-newgame", type: "checkbox" },
 353                     "class": { "modal": true },
 354                 }),
 355             h('div',
 356                 {
 357                     attrs: { "role": "dialog", "aria-labelledby": "dialog-title" },
 358                 },
 359                 [
 360                     h('div',
 361                         {
 362                             "class": { "card": true, "smallpad": true },
 363                         },
 364                         [
 365                             h('label',
 366                                 {
 367                                     attrs: { "id": "close-newgame", "for": "modal-newgame" },
 368                                     "class": { "modal-close": true },
 369                                 }
 370                             ),
 371                             h('h3',
 372                                 {
 373                                     "class": { "section": true },
 374                                     domProps: { innerHTML: "New game" },
 375                                 }
 376                             ),
 377                             h('p',
 378                                 {
 379                                     "class": { "section": true },
 380                                     domProps: { innerHTML: "Waiting for opponent..." },
 381                                 }
 382                             )
 383                         ]
 384                     )
 385                 ]
 386             )
 387         ];
 388         elementArray = elementArray.concat(modalNewgame);
 389         const actions = h('div',
 390             {
 391                 attrs: { "id": "actions" },
 392                 'class': { 'text-center': true },
 393             },
 394             actionArray
 395         );
 396         elementArray.push(actions);
 397         if (this.score != "*")
 398         {
 399             elementArray.push(
 400                 h('div',
 401                     { attrs: { id: "pgn-div" } },
 402                     [
 403                         h('a',
 404                             {
 405                                 attrs: {
 406                                     id: "download",
 407                                     href: "#",
 408                                 }
 409                             }
 410                         ),
 411                         h('p',
 412                             {
 413                                 attrs: { id: "pgn-game" },
 414                                 on: { click: this.download },
 415                                 domProps: {
 416                                     innerHTML: this.pgnTxt
 417                                 }
 418                             }
 419                         )
 420                     ]
 421                 )
 422             );
 423         }
 424         return h(
 425             'div',
 426             {
 427                 'class': {
 428                     "col-sm-12":true,
 429                     "col-md-8":true,
 430                     "col-md-offset-2":true,
 431                     "col-lg-6":true,
 432                     "col-lg-offset-3":true,
 433                 },
 434                 // NOTE: click = mousedown + mouseup --> what about smartphone?!
 435                 on: {
 436                     mousedown: this.mousedown,
 437                     mousemove: this.mousemove,
 438                     mouseup: this.mouseup,
 439                     touchdown: this.mousedown,
 440                     touchmove: this.mousemove,
 441                     touchup: this.mouseup,
 442                 },
 443             },
 444             elementArray
 445         );
 446     },
 447     created: function() {
 448         const url = socketUrl;
 449         const continuation = (localStorage.getItem("variant") === variant);
 450         this.myid = continuation
 451             ? localStorage.getItem("myid")
 452             // random enough (TODO: function)
 453             : (Date.now().toString(36) + Math.random().toString(36).substr(2, 7)).toUpperCase();
 454         if (!continuation)
 455         {
 456             // HACK: play a small silent sound to allow "new game" sound later if tab not focused
 457             new Audio("/sounds/silent.mp3").play().then(() => {}).catch(err => {});
 458         }
 459         this.conn = new WebSocket(url + "/?sid=" + this.myid + "&page=" + variant);
 460         const socketOpenListener = () => {
 461             if (continuation)
 462             {
 463                 const fen = localStorage.getItem("fen");
 464                 const mycolor = localStorage.getItem("mycolor");
 465                 const oppid = localStorage.getItem("oppid");
 466                 const moves = JSON.parse(localStorage.getItem("moves"));
 467                 this.newGame("human", fen, mycolor, oppid, moves, true);
 468                 // Send ping to server (answer pong if opponent is connected)
 469                 this.conn.send(JSON.stringify({code:"ping",oppid:this.oppid}));
 470             }
 471             else if (localStorage.getItem("newgame") === variant)
 472             {
 473                 // New game request has been cancelled on disconnect
 474                 this.seek = true;
 475                 this.newGame("human", undefined, undefined, undefined, undefined, "reconnect");
 476             }
 477         };
 478         const socketMessageListener = msg => {
 479             const data = JSON.parse(msg.data);
 480             switch (data.code)
 481             {
 482                 case "newgame": //opponent found
 483                     this.newGame("human", data.fen, data.color, data.oppid); //oppid: opponent socket ID
 484                     break;
 485                 case "newmove": //..he played!
 486                     this.play(data.move, "animate");
 487                     break;
 488                 case "pong": //received if we sent a ping (game still alive on our side)
 489                     this.oppConnected = true;
 490                     const L = this.vr.moves.length;
 491                     // Send our "last state" informations to opponent
 492                     this.conn.send(JSON.stringify({
 493                         code:"lastate",
 494                         oppid:this.oppid,
 495                         lastMove:L>0?this.vr.moves[L-1]:undefined,
 496                         movesCount:L,
 497                     }));
 498                     break;
 499                 case "lastate": //got opponent infos about last move (we might have resigned)
 500                     if (this.mode!="human" || this.oppid!=data.oppid)
 501                     {
 502                         // OK, we resigned
 503                         this.conn.send(JSON.stringify({
 504                             code:"lastate",
 505                             oppid:this.oppid,
 506                             lastMove:undefined,
 507                             movesCount:-1,
 508                         }));
 509                     }
 510                     else if (data.movesCount < 0)
 511                     {
 512                         // OK, he resigned
 513                         this.endGame(this.mycolor=="w"?"1-0":"0-1");
 514                     }
 515                     else if (data.movesCount < this.vr.moves.length)
 516                     {
 517                         // We must tell last move to opponent
 518                         const L = this.vr.moves.length;
 519                         this.conn.send(JSON.stringify({
 520                             code:"lastate",
 521                             oppid:this.oppid,
 522                             lastMove:this.vr.moves[L-1],
 523                             movesCount:L,
 524                         }));
 525                     }
 526                     else if (data.movesCount > this.vr.moves.length) //just got last move from him
 527                         this.play(data.lastMove, "animate");
 528                     break;
 529                 case "resign": //..you won!
 530                     this.endGame(this.mycolor=="w"?"1-0":"0-1");
 531                     break;
 532                 // TODO: also use (dis)connect info to count online players?
 533                 case "connect":
 534                 case "disconnect":
 535                     if (this.mode == "human" && this.oppid == data.id)
 536                         this.oppConnected = (data.code == "connect");
 537                     break;
 538             }
 539         };
 540         const socketCloseListener = () => {
 541             this.conn = new WebSocket(url + "/?sid=" + this.myid + "&page=" + variant);
 542             this.conn.addEventListener('open', socketOpenListener);
 543             this.conn.addEventListener('message', socketMessageListener);
 544             this.conn.addEventListener('close', socketCloseListener);
 545         };
 546         this.conn.onopen = socketOpenListener;
 547         this.conn.onmessage = socketMessageListener;
 548         this.conn.onclose = socketCloseListener;
 549     },
 550     methods: {
 551         download: function() {
 552             let content = document.getElementById("pgn-game").innerHTML;
 553             content = content.replace(/<br>/g, "\n");
 554             // Prepare and trigger download link
 555             let downloadAnchor = document.getElementById("download");
 556             downloadAnchor.setAttribute("download", "game.pgn");
 557             downloadAnchor.href = "data:text/plain;charset=utf-8," + encodeURIComponent(content);
 558             downloadAnchor.click();
 559         },
 560         endGame: function(score) {
 561             this.score = score;
 562             let modalBox = document.getElementById("modal-eog");
 563             modalBox.checked = true;
 564             // Variants may have special PGN structure (so next function isn't defined here)
 565             this.pgnTxt = this.vr.getPGN(this.mycolor, this.score, this.fenStart, this.mode);
 566             setTimeout(() => { modalBox.checked = false; }, 2000);
 567             if (this.mode == "human")
 568                 this.clearStorage();
 569             this.mode = "idle";
 570             this.oppid = "";
 571         },
 572         getEndgameMessage: function(score) {
 573             let eogMessage = "Unfinished";
 574             switch (this.score)
 575             {
 576                 case "1-0":
 577                     eogMessage = "White win";
 578                     break;
 579                 case "0-1":
 580                     eogMessage = "Black win";
 581                     break;
 582                 case "1/2":
 583                     eogMessage = "Draw";
 584                     break;
 585             }
 586             return eogMessage;
 587         },
 588         toggleExpertMode: function() {
 589             this.expert = !this.expert;
 590             document.cookie = "expert=" + (this.expert ? "1" : "0");
 591         },
 592         resign: function() {
 593             if (this.mode == "human" && this.oppConnected)
 594             {
 595                 try {
 596                     this.conn.send(JSON.stringify({code: "resign", oppid: this.oppid}));
 597                 } catch (INVALID_STATE_ERR) {
 598                     return; //socket is not ready (and not yet reconnected)
 599                 }
 600             }
 601             this.endGame(this.mycolor=="w"?"0-1":"1-0");
 602         },
 603         setStorage: function() {
 604             localStorage.setItem("myid", this.myid);
 605             localStorage.setItem("variant", variant);
 606             localStorage.setItem("mycolor", this.mycolor);
 607             localStorage.setItem("oppid", this.oppid);
 608             localStorage.setItem("fenStart", this.fenStart);
 609             localStorage.setItem("moves", JSON.stringify(this.vr.moves));
 610             localStorage.setItem("fen", this.vr.getFen());
 611         },
 612         updateStorage: function() {
 613             localStorage.setItem("moves", JSON.stringify(this.vr.moves));
 614             localStorage.setItem("fen", this.vr.getFen());
 615         },
 616         clearStorage: function() {
 617             delete localStorage["variant"];
 618             delete localStorage["myid"];
 619             delete localStorage["mycolor"];
 620             delete localStorage["oppid"];
 621             delete localStorage["fenStart"];
 622             delete localStorage["fen"];
 623             delete localStorage["moves"];
 624         },
 625         clickGameSeek: function() {
 626             if (this.mode == "human")
 627                 return; //no newgame while playing
 628             if (this.seek)
 629             {
 630                 delete localStorage["newgame"]; //cancel game seek
 631                 this.seek = false;
 632             }
 633             else
 634                 this.newGame("human");
 635         },
 636         clickComputerGame: function() {
 637             if (this.mode == "human")
 638                 return; //no newgame while playing
 639             this.newGame("computer");
 640         },
 641         newGame: function(mode, fenInit, color, oppId, moves, continuation) {
 642             const fen = fenInit || VariantRules.GenRandInitFen();
 643             console.log(fen); //DEBUG
 644             this.score = "*";
 645             if (mode=="human" && !oppId)
 646             {
 647                 const storageVariant = localStorage.getItem("variant");
 648                 if (!!storageVariant && storageVariant !== variant)
 649                 {
 650                     alert("Finish your " + storageVariant + " game first!");
 651                     return;
 652                 }
 653                 // Send game request and wait..
 654                 localStorage["newgame"] = variant;
 655                 this.seek = true;
 656                 this.clearStorage(); //in case of
 657                 try {
 658                     this.conn.send(JSON.stringify({code:"newgame", fen:fen}));
 659                 } catch (INVALID_STATE_ERR) {
 660                     return; //nothing achieved
 661                 }
 662                 if (continuation !== "reconnect") //TODO: bad HACK...
 663                 {
 664                     let modalBox = document.getElementById("modal-newgame");
 665                     modalBox.checked = true;
 666                     setTimeout(() => { modalBox.checked = false; }, 2000);
 667                 }
 668                 return;
 669             }
 670             // random enough (TODO: function)
 671             this.gameId = (Date.now().toString(36) + Math.random().toString(36).substr(2, 7)).toUpperCase();
 672             this.vr = new VariantRules(fen, moves || []);
 673             this.pgnTxt = ""; //redundant with this.score = "*", but cleaner
 674             this.mode = mode;
 675             this.incheck = []; //in case of
 676             this.fenStart = continuation
 677                 ? localStorage.getItem("fenStart")
 678                 : fen.split(" ")[0]; //Only the position matters
 679             if (mode=="human")
 680             {
 681                 // Opponent found!
 682                 if (!continuation)
 683                 {
 684                     // Not playing sound on game continuation:
 685                     new Audio("/sounds/newgame.mp3").play().then(() => {}).catch(err => {});
 686                     document.getElementById("modal-newgame").checked = false;
 687                 }
 688                 this.oppid = oppId;
 689                 this.oppConnected = true;
 690                 this.mycolor = color;
 691                 this.seek = false;
 692                 if (!!moves && moves.length > 0) //imply continuation
 693                 {
 694                     const lastMove = moves[moves.length-1];
 695                     this.vr.undo(lastMove);
 696                     this.incheck = this.vr.getCheckSquares(lastMove);
 697                     this.vr.play(lastMove, "ingame");
 698                 }
 699                 delete localStorage["newgame"];
 700                 this.setStorage(); //in case of interruptions
 701             }
 702             else //against computer
 703             {
 704                 this.mycolor = Math.random() < 0.5 ? 'w' : 'b';
 705                 if (this.mycolor == 'b')
 706                     setTimeout(this.playComputerMove, 500);
 707             }
 708         },
 709         playComputerMove: function() {
 710             const timeStart = Date.now();
 711             const nbMoves = this.vr.moves.length; //using played moves to know if search finished
 712             const gameId = this.gameId; //to know if game was reset before timer end
 713             setTimeout(
 714                 () => {
 715                     if (gameId != this.gameId)
 716                         return; //game stopped
 717                     const L = this.vr.moves.length;
 718                     if (nbMoves == L || !this.vr.moves[L-1].notation) //move search didn't finish
 719                         this.vr.shouldReturn = true;
 720                 }, 5000);
 721             const compMove = this.vr.getComputerMove();
 722             // (first move) HACK: avoid selecting elements before they appear on page:
 723             const delay = Math.max(500-(Date.now()-timeStart), 0);
 724             setTimeout(() => this.play(compMove, "animate"), delay);
 725         },
 726         // Get the identifier of a HTML table cell from its numeric coordinates o.x,o.y.
 727         getSquareId: function(o) {
 728             // NOTE: a separator is required to allow any size of board
 729             return  "sq-" + o.x + "-" + o.y;
 730         },
 731         // Inverse function
 732         getSquareFromId: function(id) {
 733             let idParts = id.split('-');
 734             return [parseInt(idParts[1]), parseInt(idParts[2])];
 735         },
 736         mousedown: function(e) {
 737             e = e || window.event;
 738             e.preventDefault(); //disable native drag & drop
 739             if (!this.selectedPiece && e.target.classList.contains("piece"))
 740             {
 741                 // Next few lines to center the piece on mouse cursor
 742                 let rect = e.target.parentNode.getBoundingClientRect();
 743                 this.start = {
 744                     x: rect.x + rect.width/2,
 745                     y: rect.y + rect.width/2,
 746                     id: e.target.parentNode.id
 747                 };
 748                 this.selectedPiece = e.target.cloneNode();
 749                 this.selectedPiece.style.position = "absolute";
 750                 this.selectedPiece.style.top = 0;
 751                 this.selectedPiece.style.display = "inline-block";
 752                 this.selectedPiece.style.zIndex = 3000;
 753                 let startSquare = this.getSquareFromId(e.target.parentNode.id);
 754                 this.possibleMoves = this.mode!="idle" && this.vr.canIplay(this.mycolor,startSquare)
 755                     ? this.vr.getPossibleMovesFrom(startSquare)
 756                     : [];
 757                 e.target.parentNode.appendChild(this.selectedPiece);
 758             }
 759         },
 760         mousemove: function(e) {
 761             if (!this.selectedPiece)
 762                 return;
 763             e = e || window.event;
 764             // If there is an active element, move it around
 765             if (!!this.selectedPiece)
 766             {
 767                 this.selectedPiece.style.left = (e.clientX-this.start.x) + "px";
 768                 this.selectedPiece.style.top = (e.clientY-this.start.y) + "px";
 769             }
 770         },
 771         mouseup: function(e) {
 772             if (!this.selectedPiece)
 773                 return;
 774             e = e || window.event;
 775             // Read drop target (or parentElement, parentNode... if type == "img")
 776             this.selectedPiece.style.zIndex = -3000; //HACK to find square from final coordinates
 777             let landing = document.elementFromPoint(e.clientX, e.clientY);
 778             this.selectedPiece.style.zIndex = 3000;
 779             while (landing.tagName == "IMG") //classList.contains(piece) fails because of mark/highlight
 780                 landing = landing.parentNode;
 781             if (this.start.id == landing.id) //a click: selectedPiece and possibleMoves already filled
 782                 return;
 783             // OK: process move attempt
 784             let endSquare = this.getSquareFromId(landing.id);
 785             let moves = this.findMatchingMoves(endSquare);
 786             this.possibleMoves = [];
 787             if (moves.length > 1)
 788                 this.choices = moves;
 789             else if (moves.length==1)
 790                 this.play(moves[0]);
 791             // Else: impossible move
 792             this.selectedPiece.parentNode.removeChild(this.selectedPiece);
 793             delete this.selectedPiece;
 794             this.selectedPiece = null;
 795         },
 796         findMatchingMoves: function(endSquare) {
 797             // Run through moves list and return the matching set (if promotions...)
 798             let moves = [];
 799             this.possibleMoves.forEach(function(m) {
 800                 if (endSquare[0] == m.end.x && endSquare[1] == m.end.y)
 801                     moves.push(m);
 802             });
 803             return moves;
 804         },
 805         animateMove: function(move) {
 806             let startSquare = document.getElementById(this.getSquareId(move.start));
 807             let endSquare = document.getElementById(this.getSquareId(move.end));
 808             let rectStart = startSquare.getBoundingClientRect();
 809             let rectEnd = endSquare.getBoundingClientRect();
 810             let translation = {x:rectEnd.x-rectStart.x, y:rectEnd.y-rectStart.y};
 811             let movingPiece =
 812                 document.querySelector("#" + this.getSquareId(move.start) + " > img.piece");
 813             // HACK for animation (with positive translate, image slides "under background"...)
 814             // Possible improvement: just alter squares on the piece's way...
 815             squares = document.getElementsByClassName("board");
 816             for (let i=0; i<squares.length; i++)
 817             {
 818                 let square = squares.item(i);
 819                 if (square.id != this.getSquareId(move.start))
 820                     square.style.zIndex = "-1";
 821             }
 822             movingPiece.style.transform = "translate(" + translation.x + "px," + translation.y + "px)";
 823             movingPiece.style.transitionDuration = "0.2s";
 824             movingPiece.style.zIndex = "3000";
 825             setTimeout( () => {
 826                 for (let i=0; i<squares.length; i++)
 827                     squares.item(i).style.zIndex = "auto";
 828                 movingPiece.style = {}; //required e.g. for 0-0 with KR swap
 829                 this.play(move);
 830             }, 200);
 831         },
 832         play: function(move, programmatic) {
 833             if (!!programmatic) //computer or human opponent
 834             {
 835                 this.animateMove(move);
 836                 return;
 837             }
 838             this.incheck = this.vr.getCheckSquares(move); //is opponent in check?
 839             // Not programmatic, or animation is over
 840             if (this.mode == "human" && this.vr.turn == this.mycolor)
 841                 this.conn.send(JSON.stringify({code:"newmove", move:move, oppid:this.oppid}));
 842             new Audio("/sounds/chessmove1.mp3").play().then(() => {}).catch(err => {});
 843             this.vr.play(move, "ingame");
 844             if (this.mode == "human")
 845                 this.updateStorage(); //after our moves and opponent moves
 846             const eog = this.vr.checkGameOver();
 847             if (eog != "*")
 848                 this.endGame(eog);
 849             else if (this.mode == "computer" && this.vr.turn != this.mycolor)
 850                 setTimeout(this.playComputerMove, 500);
 851         },
 852     },
 853 })