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