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         };
  21     },
  22     render(h) {
  23         const [sizeX,sizeY] = VariantRules.size;
  24         // Precompute hints squares to facilitate rendering
  25         let hintSquares = doubleArray(sizeX, sizeY, false);
  26         this.possibleMoves.forEach(m => { hintSquares[m.end.x][m.end.y] = true; });
  27         // Also precompute in-check squares
  28         let incheckSq = doubleArray(sizeX, sizeY, false);
  29         this.incheck.forEach(sq => { incheckSq[sq[0]][sq[1]] = true; });
  30         let elementArray = [];
  31         const playingHuman = (this.mode == "human");
  32         const playingComp = (this.mode == "computer");
  33         let actionArray = [
  34             h('button',
  35                 {
  36                     on: { click: this.clickGameSeek },
  37                     attrs: { "aria-label": 'New game VS human' },
  38                     'class': {
  39                         "tooltip": true,
  40                         "bottom": true, //display below
  41                         "seek": this.seek,
  42                         "playing": playingHuman,
  43                     },
  44                 },
  45                 [h('i', { 'class': { "material-icons": true } }, "accessibility")]),
  46             h('button',
  47                 {
  48                     on: { click: this.clickComputerGame },
  49                     attrs: { "aria-label": 'New game VS computer' },
  50                     'class': {
  51                         "tooltip":true,
  52                         "bottom": true,
  53                         "playing": playingComp,
  54                     },
  55                 },
  56                 [h('i', { 'class': { "material-icons": true } }, "computer")])
  57         ];
  58         if (!!this.vr)
  59         {
  60             const square00 = document.getElementById("sq-0-0");
  61             const squareWidth = !!square00
  62                 ? parseFloat(window.getComputedStyle(square00).width.slice(0,-2))
  63                 : 0;
  64             const indicWidth = (squareWidth>0 ? squareWidth/2 : 20);
  65             if (this.mode == "human")
  66             {
  67                 let connectedIndic = h(
  68                     'div',
  69                     {
  70                         "class": {
  71                             "topindicator": true,
  72                             "indic-left": true,
  73                             "connected": this.oppConnected,
  74                             "disconnected": !this.oppConnected,
  75                         },
  76                         style: {
  77                             "width": indicWidth + "px",
  78                             "height": indicWidth + "px",
  79                         },
  80                     }
  81                 );
  82                 elementArray.push(connectedIndic);
  83             }
  84             let turnIndic = h(
  85                 'div',
  86                 {
  87                     "class": {
  88                         "topindicator": true,
  89                         "indic-right": true,
  90                         "white-turn": this.vr.turn=="w",
  91                         "black-turn": this.vr.turn=="b",
  92                     },
  93                     style: {
  94                         "width": indicWidth + "px",
  95                         "height": indicWidth + "px",
  96                     },
  97                 }
  98             );
  99             elementArray.push(turnIndic);
 100             let expertSwitch = h(
 101                 'button',
 102                 {
 103                     on: { click: this.toggleExpertMode },
 104                     attrs: { "aria-label": 'Toggle expert mode' },
 105                     'class': {
 106                         "tooltip":true,
 107                         "topindicator": true,
 108                         "indic-right": true,
 109                         "expert-switch": true,
 110                         "expert-mode": this.expert,
 111                     },
 112                 },
 113                 [h('i', { 'class': { "material-icons": true } }, "remove_red_eye")]
 114             );
 115             elementArray.push(expertSwitch);
 116             let choices = h('div',
 117                 {
 118                     attrs: { "id": "choices" },
 119                     'class': { 'row': true },
 120                     style: {
 121                         "display": this.choices.length>0?"block":"none",
 122                         "top": "-" + ((sizeY/2)*squareWidth+squareWidth/2) + "px",
 123                         "width": (this.choices.length * squareWidth) + "px",
 124                         "height": squareWidth + "px",
 125                     },
 126                 },
 127                 this.choices.map( m => { //a "choice" is a move
 128                     return h('div',
 129                         {
 130                             'class': {
 131                                 'board': true,
 132                                 ['board'+sizeY]: true,
 133                             },
 134                             style: {
 135                                 'width': (100/this.choices.length) + "%",
 136                                 'padding-bottom': (100/this.choices.length) + "%",
 137                             },
 138                         },
 139                         [h('img',
 140                             {
 141                                 attrs: { "src": '/images/pieces/' +
 142                                     VariantRules.getPpath(m.appear[0].c+m.appear[0].p) + '.svg' },
 143                                 'class': { 'choice-piece': true },
 144                                 on: { "click": e => { this.play(m); this.choices=[]; } },
 145                             })
 146                         ]
 147                     );
 148                 })
 149             );
 150             // Create board element (+ reserves if needed by variant or mode)
 151             let gameDiv = h('div',
 152                 {
 153                     'class': { 'game': true },
 154                 },
 155                 [_.range(sizeX).map(i => {
 156                     let ci = this.mycolor=='w' ? i : sizeX-i-1;
 157                     return h(
 158                         'div',
 159                         {
 160                             'class': {
 161                                 'row': true,
 162                             },
 163                             style: { 'opacity': this.choices.length>0?"0.5":"1" },
 164                         },
 165                         _.range(sizeY).map(j => {
 166                             let cj = this.mycolor=='w' ? j : sizeY-j-1;
 167                             let elems = [];
 168                             if (this.vr.board[ci][cj] != VariantRules.EMPTY)
 169                             {
 170                                 elems.push(
 171                                     h(
 172                                         'img',
 173                                         {
 174                                             'class': {
 175                                                 'piece': true,
 176                                                 'ghost': !!this.selectedPiece
 177                                                     && this.selectedPiece.parentNode.id == "sq-"+ci+"-"+cj,
 178                                             },
 179                                             attrs: {
 180                                                 src: "/images/pieces/" +
 181                                                     VariantRules.getPpath(this.vr.board[ci][cj]) + ".svg",
 182                                             },
 183                                         }
 184                                     )
 185                                 );
 186                             }
 187                             if (!this.expert && hintSquares[ci][cj])
 188                             {
 189                                 elems.push(
 190                                     h(
 191                                         'img',
 192                                         {
 193                                             'class': {
 194                                                 'mark-square': true,
 195                                             },
 196                                             attrs: {
 197                                                 src: "/images/mark.svg",
 198                                             },
 199                                         }
 200                                     )
 201                                 );
 202                             }
 203                             const lm = this.vr.lastMove;
 204                             const highlight = !!lm && _.isMatch(lm.end, {x:ci,y:cj});
 205                             return h(
 206                                 'div',
 207                                 {
 208                                     'class': {
 209                                         'board': true,
 210                                         ['board'+sizeY]: true,
 211                                         'light-square': (i+j)%2==0 && (this.expert || !highlight),
 212                                         'dark-square': (i+j)%2==1 && (this.expert || !highlight),
 213                                         'highlight': !this.expert && highlight,
 214                                         'incheck': !this.expert && incheckSq[ci][cj],
 215                                     },
 216                                     attrs: {
 217                                         id: this.getSquareId({x:ci,y:cj}),
 218                                     },
 219                                 },
 220                                 elems
 221                             );
 222                         })
 223                     );
 224                 }), choices]
 225             );
 226             if (this.mode != "idle")
 227             {
 228                 actionArray.push(
 229                     h('button',
 230                         {
 231                             on: { click: this.resign },
 232                             attrs: { "aria-label": 'Resign' },
 233                             'class': {
 234                                 "tooltip":true,
 235                                 "bottom": true,
 236                             },
 237                         },
 238                         [h('i', { 'class': { "material-icons": true } }, "flag")])
 239                 );
 240             }
 241             elementArray.push(gameDiv);
 242     //          if (!!vr.reserve)
 243     //          {
 244     //              let reserve = h('div',
 245     //                  {'class':{'game':true}}, [
 246     //                      h('div',
 247     //                          { 'class': { 'row': true }},
 248     //                          [
 249     //                              h('div',
 250     //                                  {'class':{'board':true}},
 251     //                                  [h('img',{'class':{"piece":true},attrs:{"src":"/images/pieces/wb.svg"}})]
 252     //                              )
 253     //                          ]
 254     //                      )
 255     //                  ],
 256     //              );
 257     //              elementArray.push(reserve);
 258     //          }
 259             const eogMessage = this.getEndgameMessage(this.score);
 260             const modalEog = [
 261                 h('input',
 262                     {
 263                         attrs: { "id": "modal-eog", type: "checkbox" },
 264                         "class": { "modal": true },
 265                     }),
 266                 h('div',
 267                     {
 268                         attrs: { "role": "dialog", "aria-labelledby": "dialog-title" },
 269                     },
 270                     [
 271                         h('div',
 272                             {
 273                                 "class": { "card": true, "smallpad": true },
 274                             },
 275                             [
 276                                 h('label',
 277                                     {
 278                                         attrs: { "for": "modal-eog" },
 279                                         "class": { "modal-close": true },
 280                                     }
 281                                 ),
 282                                 h('h3',
 283                                     {
 284                                         "class": { "section": true },
 285                                         domProps: { innerHTML: eogMessage },
 286                                     }
 287                                 )
 288                             ]
 289                         )
 290                     ]
 291                 )
 292             ];
 293             elementArray = elementArray.concat(modalEog);
 294         }
 295         const modalNewgame = [
 296             h('input',
 297                 {
 298                     attrs: { "id": "modal-newgame", type: "checkbox" },
 299                     "class": { "modal": true },
 300                 }),
 301             h('div',
 302                 {
 303                     attrs: { "role": "dialog", "aria-labelledby": "dialog-title" },
 304                 },
 305                 [
 306                     h('div',
 307                         {
 308                             "class": { "card": true, "smallpad": true },
 309                         },
 310                         [
 311                             h('label',
 312                                 {
 313                                     attrs: { "id": "close-newgame", "for": "modal-newgame" },
 314                                     "class": { "modal-close": true },
 315                                 }
 316                             ),
 317                             h('h3',
 318                                 {
 319                                     "class": { "section": true },
 320                                     domProps: { innerHTML: "New game" },
 321                                 }
 322                             ),
 323                             h('p',
 324                                 {
 325                                     "class": { "section": true },
 326                                     domProps: { innerHTML: "Waiting for opponent..." },
 327                                 }
 328                             )
 329                         ]
 330                     )
 331                 ]
 332             )
 333         ];
 334         elementArray = elementArray.concat(modalNewgame);
 335         const actions = h('div',
 336             {
 337                 attrs: { "id": "actions" },
 338                 'class': { 'text-center': true },
 339             },
 340             actionArray
 341         );
 342         elementArray.push(actions);
 343         if (this.score != "*")
 344         {
 345             elementArray.push(
 346                 h('div',
 347                     { attrs: { id: "pgn-div" } },
 348                     [
 349                         h('a',
 350                             {
 351                                 attrs: {
 352                                     id: "download",
 353                                     href: "#",
 354                                 }
 355                             }
 356                         ),
 357                         h('p',
 358                             {
 359                                 attrs: { id: "pgn-game" },
 360                                 on: { click: this.download },
 361                                 domProps: {
 362                                     innerHTML: this.pgnTxt
 363                                 }
 364                             }
 365                         )
 366                     ]
 367                 )
 368             );
 369         }
 370         return h(
 371             'div',
 372             {
 373                 'class': {
 374                     "col-sm-12":true,
 375                     "col-md-8":true,
 376                     "col-md-offset-2":true,
 377                     "col-lg-6":true,
 378                     "col-lg-offset-3":true,
 379                 },
 380                 // NOTE: click = mousedown + mouseup --> what about smartphone?!
 381                 on: {
 382                     mousedown: this.mousedown,
 383                     mousemove: this.mousemove,
 384                     mouseup: this.mouseup,
 385                     touchdown: this.mousedown,
 386                     touchmove: this.mousemove,
 387                     touchup: this.mouseup,
 388                 },
 389             },
 390             elementArray
 391         );
 392     },
 393     created: function() {
 394         const url = socketUrl;
 395         const continuation = (localStorage.getItem("variant") === variant);
 396         this.myid = continuation
 397             ? localStorage.getItem("myid")
 398             // random enough (TODO: function)
 399             : (Date.now().toString(36) + Math.random().toString(36).substr(2, 7)).toUpperCase();
 400         if (!continuation)
 401         {
 402             // HACK: play a small silent sound to allow "new game" sound later if tab not focused
 403             new Audio("/sounds/silent.mp3").play().then(() => {}).catch(err => {});
 404         }
 405         this.conn = new WebSocket(url + "/?sid=" + this.myid + "&page=" + variant);
 406         const socketOpenListener = () => {
 407             if (continuation)
 408             {
 409                 const fen = localStorage.getItem("fen");
 410                 const mycolor = localStorage.getItem("mycolor");
 411                 const oppid = localStorage.getItem("oppid");
 412                 const moves = JSON.parse(localStorage.getItem("moves"));
 413                 this.newGame("human", fen, mycolor, oppid, moves, true);
 414                 // Send ping to server (answer pong if opponent is connected)
 415                 this.conn.send(JSON.stringify({code:"ping",oppid:this.oppid}));
 416             }
 417             else if (localStorage.getItem("newgame") === variant)
 418             {
 419                 // New game request has been cancelled on disconnect
 420                 this.seek = true;
 421                 this.newGame("human", undefined, undefined, undefined, undefined, "reconnect");
 422             }
 423         };
 424         const socketMessageListener = msg => {
 425             const data = JSON.parse(msg.data);
 426             switch (data.code)
 427             {
 428                 case "newgame": //opponent found
 429                     this.newGame("human", data.fen, data.color, data.oppid); //oppid: opponent socket ID
 430                     break;
 431                 case "newmove": //..he played!
 432                     this.play(data.move, "animate");
 433                     break;
 434                 case "pong": //received if we sent a ping (game still alive on our side)
 435                     this.oppConnected = true;
 436                     const L = this.vr.moves.length;
 437                     // Send our "last state" informations to opponent
 438                     this.conn.send(JSON.stringify({
 439                         code:"lastate",
 440                         oppid:this.oppid,
 441                         lastMove:L>0?this.vr.moves[L-1]:undefined,
 442                         movesCount:L,
 443                     }));
 444                     break;
 445                 case "lastate": //got opponent infos about last move (we might have resigned)
 446                     if (this.mode!="human" || this.oppid!=data.oppid)
 447                     {
 448                         // OK, we resigned
 449                         this.conn.send(JSON.stringify({
 450                             code:"lastate",
 451                             oppid:this.oppid,
 452                             lastMove:undefined,
 453                             movesCount:-1,
 454                         }));
 455                     }
 456                     else if (data.movesCount < 0)
 457                     {
 458                         // OK, he resigned
 459                         this.endGame(this.mycolor=="w"?"1-0":"0-1");
 460                     }
 461                     else if (data.movesCount < this.vr.moves.length)
 462                     {
 463                         // We must tell last move to opponent
 464                         const L = this.vr.moves.length;
 465                         this.conn.send(JSON.stringify({
 466                             code:"lastate",
 467                             oppid:this.oppid,
 468                             lastMove:this.vr.moves[L-1],
 469                             movesCount:L,
 470                         }));
 471                     }
 472                     else if (data.movesCount > this.vr.moves.length) //just got last move from him
 473                         this.play(data.lastMove, "animate");
 474                     break;
 475                 case "resign": //..you won!
 476                     this.endGame(this.mycolor=="w"?"1-0":"0-1");
 477                     break;
 478                 // TODO: also use (dis)connect info to count online players?
 479                 case "connect":
 480                 case "disconnect":
 481                     if (this.mode == "human" && this.oppid == data.id)
 482                         this.oppConnected = (data.code == "connect");
 483                     break;
 484             }
 485         };
 486         const socketCloseListener = () => {
 487             this.conn = new WebSocket(url + "/?sid=" + this.myid + "&page=" + variant);
 488             this.conn.addEventListener('open', socketOpenListener);
 489             this.conn.addEventListener('message', socketMessageListener);
 490             this.conn.addEventListener('close', socketCloseListener);
 491         };
 492         this.conn.onopen = socketOpenListener;
 493         this.conn.onmessage = socketMessageListener;
 494         this.conn.onclose = socketCloseListener;
 495     },
 496     methods: {
 497         download: function() {
 498             let content = document.getElementById("pgn-game").innerHTML;
 499             content = content.replace(/<br>/g, "\n");
 500             // Prepare and trigger download link
 501             let downloadAnchor = document.getElementById("download");
 502             downloadAnchor.setAttribute("download", "game.pgn");
 503             downloadAnchor.href = "data:text/plain;charset=utf-8," + encodeURIComponent(content);
 504             downloadAnchor.click();
 505         },
 506         endGame: function(score) {
 507             this.score = score;
 508             let modalBox = document.getElementById("modal-eog");
 509             modalBox.checked = true;
 510             // Variants may have special PGN structure (so next function isn't defined here)
 511             this.pgnTxt = this.vr.getPGN(this.mycolor, this.score, this.fenStart, this.mode);
 512             setTimeout(() => { modalBox.checked = false; }, 2000);
 513             if (this.mode == "human")
 514                 this.clearStorage();
 515             this.mode = "idle";
 516             this.oppid = "";
 517         },
 518         getEndgameMessage: function(score) {
 519             let eogMessage = "Unfinished";
 520             switch (this.score)
 521             {
 522                 case "1-0":
 523                     eogMessage = "White win";
 524                     break;
 525                 case "0-1":
 526                     eogMessage = "Black win";
 527                     break;
 528                 case "1/2":
 529                     eogMessage = "Draw";
 530                     break;
 531             }
 532             return eogMessage;
 533         },
 534         toggleExpertMode: function() {
 535             this.expert = !this.expert;
 536             document.cookie = "expert=" + (this.expert ? "1" : "0");
 537         },
 538         resign: function() {
 539             if (this.mode == "human" && this.oppConnected)
 540             {
 541                 try {
 542                     this.conn.send(JSON.stringify({code: "resign", oppid: this.oppid}));
 543                 } catch (INVALID_STATE_ERR) {
 544                     return; //socket is not ready (and not yet reconnected)
 545                 }
 546             }
 547             this.endGame(this.mycolor=="w"?"0-1":"1-0");
 548         },
 549         setStorage: function() {
 550             localStorage.setItem("myid", this.myid);
 551             localStorage.setItem("variant", variant);
 552             localStorage.setItem("mycolor", this.mycolor);
 553             localStorage.setItem("oppid", this.oppid);
 554             localStorage.setItem("fenStart", this.fenStart);
 555             localStorage.setItem("moves", JSON.stringify(this.vr.moves));
 556             localStorage.setItem("fen", this.vr.getFen());
 557         },
 558         updateStorage: function() {
 559             localStorage.setItem("moves", JSON.stringify(this.vr.moves));
 560             localStorage.setItem("fen", this.vr.getFen());
 561         },
 562         clearStorage: function() {
 563             delete localStorage["variant"];
 564             delete localStorage["myid"];
 565             delete localStorage["mycolor"];
 566             delete localStorage["oppid"];
 567             delete localStorage["fenStart"];
 568             delete localStorage["fen"];
 569             delete localStorage["moves"];
 570         },
 571         clickGameSeek: function() {
 572             if (this.mode == "human")
 573                 return; //no newgame while playing
 574             if (this.seek)
 575             {
 576                 delete localStorage["newgame"]; //cancel game seek
 577                 this.seek = false;
 578             }
 579             else
 580                 this.newGame("human");
 581         },
 582         clickComputerGame: function() {
 583             if (this.mode == "human")
 584                 return; //no newgame while playing
 585             this.newGame("computer");
 586         },
 587         newGame: function(mode, fenInit, color, oppId, moves, continuation) {
 588             //const fen = "1n2T1n0/p2pO2p/1s1k1s2/8/3S2p1/2U2cO1/P3PuPP/3K1BR1 0100";
 589             const fen = fenInit || VariantRules.GenRandInitFen();
 590             console.log(fen); //DEBUG
 591             this.score = "*";
 592             if (mode=="human" && !oppId)
 593             {
 594                 const storageVariant = localStorage.getItem("variant");
 595                 if (!!storageVariant && storageVariant !== variant)
 596                 {
 597                     alert("Finish your " + storageVariant + " game first!");
 598                     return;
 599                 }
 600                 // Send game request and wait..
 601                 localStorage["newgame"] = variant;
 602                 this.seek = true;
 603                 this.clearStorage(); //in case of
 604                 try {
 605                     this.conn.send(JSON.stringify({code:"newgame", fen:fen}));
 606                 } catch (INVALID_STATE_ERR) {
 607                     return; //nothing achieved
 608                 }
 609                 if (continuation !== "reconnect") //TODO: bad HACK...
 610                 {
 611                     let modalBox = document.getElementById("modal-newgame");
 612                     modalBox.checked = true;
 613                     setTimeout(() => { modalBox.checked = false; }, 2000);
 614                 }
 615                 return;
 616             }
 617             this.vr = new VariantRules(fen, moves || []);
 618             this.pgnTxt = ""; //redundant with this.score = "*", but cleaner
 619             this.mode = mode;
 620             this.incheck = []; //in case of
 621             this.fenStart = continuation
 622                 ? localStorage.getItem("fenStart")
 623                 : fen.split(" ")[0]; //Only the position matters
 624             if (mode=="human")
 625             {
 626                 // Opponent found!
 627                 if (!continuation)
 628                 {
 629                     // Not playing sound on game continuation:
 630                     new Audio("/sounds/newgame.mp3").play().then(() => {}).catch(err => {});
 631                     document.getElementById("modal-newgame").checked = false;
 632                 }
 633                 this.oppid = oppId;
 634                 this.oppConnected = true;
 635                 this.mycolor = color;
 636                 this.seek = false;
 637                 if (!!moves && moves.length > 0) //imply continuation
 638                 {
 639                     const lastMove = moves[moves.length-1];
 640                     this.vr.undo(lastMove);
 641                     this.incheck = this.vr.getCheckSquares(lastMove);
 642                     this.vr.play(lastMove, "ingame");
 643                 }
 644                 delete localStorage["newgame"];
 645                 this.setStorage(); //in case of interruptions
 646             }
 647             else //against computer
 648             {
 649                 this.mycolor = Math.random() < 0.5 ? 'w' : 'b';
 650                 if (this.mycolor == 'b')
 651                     setTimeout(this.playComputerMove, 500);
 652             }
 653         },
 654         playComputerMove: function() {
 655             const timeStart = Date.now();
 656             const nbMoves = this.vr.moves.length; //using played moves to know if search finished
 657             setTimeout(
 658                 () => {
 659                     const L = this.vr.moves.length;
 660                     if (nbMoves == L || !this.vr.moves[L-1].notation) //move search didn't finish
 661                         this.vr.shouldReturn = true;
 662                 }, 5000);
 663             const compMove = this.vr.getComputerMove();
 664             // (first move) HACK: avoid selecting elements before they appear on page:
 665             const delay = Math.max(500-(Date.now()-timeStart), 0);
 666             setTimeout(() => this.play(compMove, "animate"), delay);
 667         },
 668         // Get the identifier of a HTML table cell from its numeric coordinates o.x,o.y.
 669         getSquareId: function(o) {
 670             // NOTE: a separator is required to allow any size of board
 671             return  "sq-" + o.x + "-" + o.y;
 672         },
 673         // Inverse function
 674         getSquareFromId: function(id) {
 675             let idParts = id.split('-');
 676             return [parseInt(idParts[1]), parseInt(idParts[2])];
 677         },
 678         mousedown: function(e) {
 679             e = e || window.event;
 680             e.preventDefault(); //disable native drag & drop
 681             if (!this.selectedPiece && e.target.classList.contains("piece"))
 682             {
 683                 // Next few lines to center the piece on mouse cursor
 684                 let rect = e.target.parentNode.getBoundingClientRect();
 685                 this.start = {
 686                     x: rect.x + rect.width/2,
 687                     y: rect.y + rect.width/2,
 688                     id: e.target.parentNode.id
 689                 };
 690                 this.selectedPiece = e.target.cloneNode();
 691                 this.selectedPiece.style.position = "absolute";
 692                 this.selectedPiece.style.top = 0;
 693                 this.selectedPiece.style.display = "inline-block";
 694                 this.selectedPiece.style.zIndex = 3000;
 695                 let startSquare = this.getSquareFromId(e.target.parentNode.id);
 696                 this.possibleMoves = this.mode!="idle" && this.vr.canIplay(this.mycolor,startSquare)
 697                     ? this.vr.getPossibleMovesFrom(startSquare)
 698                     : [];
 699                 e.target.parentNode.appendChild(this.selectedPiece);
 700             }
 701         },
 702         mousemove: function(e) {
 703             if (!this.selectedPiece)
 704                 return;
 705             e = e || window.event;
 706             // If there is an active element, move it around
 707             if (!!this.selectedPiece)
 708             {
 709                 this.selectedPiece.style.left = (e.clientX-this.start.x) + "px";
 710                 this.selectedPiece.style.top = (e.clientY-this.start.y) + "px";
 711             }
 712         },
 713         mouseup: function(e) {
 714             if (!this.selectedPiece)
 715                 return;
 716             e = e || window.event;
 717             // Read drop target (or parentElement, parentNode... if type == "img")
 718             this.selectedPiece.style.zIndex = -3000; //HACK to find square from final coordinates
 719             let landing = document.elementFromPoint(e.clientX, e.clientY);
 720             this.selectedPiece.style.zIndex = 3000;
 721             while (landing.tagName == "IMG") //classList.contains(piece) fails because of mark/highlight
 722                 landing = landing.parentNode;
 723             if (this.start.id == landing.id) //a click: selectedPiece and possibleMoves already filled
 724                 return;
 725             // OK: process move attempt
 726             let endSquare = this.getSquareFromId(landing.id);
 727             let moves = this.findMatchingMoves(endSquare);
 728             this.possibleMoves = [];
 729             if (moves.length > 1)
 730                 this.choices = moves;
 731             else if (moves.length==1)
 732                 this.play(moves[0]);
 733             // Else: impossible move
 734             this.selectedPiece.parentNode.removeChild(this.selectedPiece);
 735             delete this.selectedPiece;
 736             this.selectedPiece = null;
 737         },
 738         findMatchingMoves: function(endSquare) {
 739             // Run through moves list and return the matching set (if promotions...)
 740             let moves = [];
 741             this.possibleMoves.forEach(function(m) {
 742                 if (endSquare[0] == m.end.x && endSquare[1] == m.end.y)
 743                     moves.push(m);
 744             });
 745             return moves;
 746         },
 747         animateMove: function(move) {
 748             let startSquare = document.getElementById(this.getSquareId(move.start));
 749             let endSquare = document.getElementById(this.getSquareId(move.end));
 750             let rectStart = startSquare.getBoundingClientRect();
 751             let rectEnd = endSquare.getBoundingClientRect();
 752             let translation = {x:rectEnd.x-rectStart.x, y:rectEnd.y-rectStart.y};
 753             let movingPiece =
 754                 document.querySelector("#" + this.getSquareId(move.start) + " > img.piece");
 755             // HACK for animation (with positive translate, image slides "under background"...)
 756             // Possible improvement: just alter squares on the piece's way...
 757             squares = document.getElementsByClassName("board");
 758             for (let i=0; i<squares.length; i++)
 759             {
 760                 let square = squares.item(i);
 761                 if (square.id != this.getSquareId(move.start))
 762                     square.style.zIndex = "-1";
 763             }
 764             movingPiece.style.transform = "translate(" + translation.x + "px," + translation.y + "px)";
 765             movingPiece.style.transitionDuration = "0.2s";
 766             movingPiece.style.zIndex = "3000";
 767             setTimeout( () => {
 768                 for (let i=0; i<squares.length; i++)
 769                     squares.item(i).style.zIndex = "auto";
 770                 movingPiece.style = {}; //required e.g. for 0-0 with KR swap
 771                 this.play(move);
 772             }, 200);
 773         },
 774         play: function(move, programmatic) {
 775             if (!!programmatic) //computer or human opponent
 776             {
 777                 this.animateMove(move);
 778                 return;
 779             }
 780             this.incheck = this.vr.getCheckSquares(move); //is opponent in check?
 781             // Not programmatic, or animation is over
 782             if (this.mode == "human" && this.vr.turn == this.mycolor)
 783                 this.conn.send(JSON.stringify({code:"newmove", move:move, oppid:this.oppid}));
 784             new Audio("/sounds/chessmove1.mp3").play().then(() => {}).catch(err => {});
 785             this.vr.play(move, "ingame");
 786             if (this.mode == "human")
 787                 this.updateStorage(); //after our moves and opponent moves
 788             const eog = this.vr.checkGameOver();
 789             if (eog != "*")
 790                 this.endGame(eog);
 791             else if (this.mode == "computer" && this.vr.turn != this.mycolor)
 792                 setTimeout(this.playComputerMove, 500);
 793         },
 794     },
 795 })