public/javascripts/components/game.js

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