client/src/components/BaseGame.vue

   1 <template lang="pug">
   2 div#baseGame
   3   input#modalEog.modal(type="checkbox")
   4   div#eogDiv(
   5     role="dialog"
   6     data-checkbox="modalEog"
   7   )
   8     .card.text-center
   9       label.modal-close(for="modalEog")
  10       h3.section {{ endgameMessage }}
  11   #gameContainer
  12     #boardContainer
  13       Board(
  14         ref="board"
  15         :vr="vr"
  16         :last-move="lastMove"
  17         :analyze="mode=='analyze'"
  18         :score="game.score"
  19         :user-color="game.mycolor"
  20         :orientation="orientation"
  21         :vname="game.vname"
  22         :incheck="incheck"
  23         @play-move="play"
  24         @click-square="clickSquare"
  25       )
  26       #turnIndicator(v-if="showTurn") {{ turn }}
  27       #controls.button-group
  28         button(@click="gotoBegin()")
  29           img.inline(src="/images/icons/fast-forward_rev.svg")
  30         button(@click="undo()")
  31           img.inline(src="/images/icons/play_rev.svg")
  32         button(v-if="canFlip" @click="flip()")
  33           img.inline(src="/images/icons/flip.svg")
  34         button(
  35           @click="runAutoplay()"
  36           :class="{'in-autoplay': autoplay}"
  37         )
  38           img.inline(src="/images/icons/autoplay.svg")
  39         button(@click="play()")
  40           img.inline(src="/images/icons/play.svg")
  41         button(@click="gotoEnd()")
  42           img.inline(src="/images/icons/fast-forward.svg")
  43       p#fenAnalyze(v-show="showFen") {{ (!!vr ? vr.getFen() : "") }}
  44     #movesList
  45       MoveList(
  46         :show="showMoves"
  47         :canAnalyze="canAnalyze"
  48         :canDownload="allowDownloadPGN"
  49         :score="game.score"
  50         :message="game.scoreMsg"
  51         :firstNum="firstMoveNumber"
  52         :moves="moves"
  53         :cursor="cursor"
  54         :vname="game.vname"
  55         @download="download"
  56         @showrules="showRules"
  57         @analyze="toggleAnalyze"
  58         @goto-move="gotoMove"
  59         @redraw-board="redrawBoard"
  60       )
  61     .clearer
  62 </template>
  63
  64 <script>
  65 import Board from "@/components/Board.vue";
  66 import MoveList from "@/components/MoveList.vue";
  67 import params from "@/parameters";
  68 import { store } from "@/store";
  69 import { getSquareId } from "@/utils/squareId";
  70 import { getDate } from "@/utils/datetime";
  71 import { processModalClick } from "@/utils/modalClick";
  72 import { getScoreMessage } from "@/utils/scoring";
  73 import { getFullNotation } from "@/utils/notation";
  74 import { undoMove } from "@/utils/playUndo";
  75 export default {
  76   name: "my-base-game",
  77   components: {
  78     Board,
  79     MoveList
  80   },
  81   props: ["game"],
  82   data: function() {
  83     return {
  84       st: store.state,
  85       // NOTE: all following variables must be reset at the beginning of a game
  86       vr: null, //VariantRules object, game state
  87       endgameMessage: "",
  88       orientation: "w",
  89       mode: "",
  90       gameMode: "",
  91       score: "*", //'*' means 'unfinished'
  92       moves: [],
  93       cursor: -1, //index of the move just played
  94       lastMove: null,
  95       touchLastClick: "",
  96       firstMoveNumber: 0, //for printing
  97       incheck: [], //for Board
  98       inMultimove: false,
  99       autoplay: false,
 100       inPlay: false,
 101       stackToPlay: []
 102     };
 103   },
 104   computed: {
 105     turn: function() {
 106       if (!this.vr) return "";
 107       if (this.vr.showMoves != "all") {
 108         return this.st.tr[
 109           (this.vr.turn == 'w' ? "White" : "Black") + " to move"];
 110       }
 111       // Cannot flip (racing king or circular chess), or Monochrome
 112       return (
 113         this.vr.movesCount == 0 && this.game.mycolor == "w"
 114           ? this.st.tr["It's your turn!"]
 115           : ""
 116       );
 117     },
 118     showFen: function() {
 119       return (
 120         this.mode == "analyze" &&
 121         this.$router.currentRoute.path.indexOf("/analyse") === -1
 122       );
 123     },
 124     // TODO: is it OK to pass "computed" as properties?
 125     // Also, some are seemingly not recomputed when vr is initialized.
 126     showMoves: function() {
 127       return (
 128         !!this.game.score && this.game.score != "*"
 129           ? "all"
 130           : (!!this.vr ? this.vr.showMoves : "none")
 131       );
 132     },
 133     showTurn: function() {
 134       return (
 135         !!this.game.score && this.game.score == '*' &&
 136         !!this.vr &&
 137         (
 138           this.vr.showMoves != "all" ||
 139           !this.vr.canFlip ||
 140           this.vr.showFirstTurn
 141         )
 142       );
 143     },
 144     canAnalyze: function() {
 145       return (
 146         (!this.game.mode || this.game.mode != "analyze") &&
 147         !!this.vr && this.vr.canAnalyze
 148       );
 149     },
 150     canFlip: function() {
 151       return !!this.vr && this.vr.canFlip;
 152     },
 153     allowDownloadPGN: function() {
 154       return (
 155         (!!this.game.score && this.game.score != "*") ||
 156         (!!this.vr && !this.vr.someHiddenMoves)
 157       );
 158     }
 159   },
 160   created: function() {
 161     if (!!this.game.fenStart) this.re_setVariables();
 162   },
 163   mounted: function() {
 164     if (!("ontouchstart" in window)) {
 165       // Desktop browser:
 166       const baseGameDiv = document.getElementById("baseGame");
 167       baseGameDiv.tabIndex = 0;
 168       baseGameDiv.addEventListener("click", this.focusBg);
 169       baseGameDiv.addEventListener("keydown", this.handleKeys);
 170       if (this.st.settings.scrollmove)
 171         baseGameDiv.addEventListener("wheel", this.handleScroll);
 172     }
 173     document.getElementById("eogDiv")
 174       .addEventListener("click", processModalClick);
 175   },
 176   beforeDestroy: function() {
 177     // TODO: probably not required
 178     this.autoplay = false;
 179   },
 180   methods: {
 181     focusBg: function() {
 182       document.getElementById("baseGame").focus();
 183     },
 184     handleKeys: function(e) {
 185       if ([32, 37, 38, 39, 40].includes(e.keyCode)) e.preventDefault();
 186       switch (e.keyCode) {
 187         case 37:
 188           this.undo();
 189           break;
 190         case 39:
 191           this.play();
 192           break;
 193         case 38:
 194           this.gotoBegin();
 195           break;
 196         case 40:
 197           this.gotoEnd();
 198           break;
 199         case 32:
 200           this.flip();
 201           break;
 202       }
 203     },
 204     handleScroll: function(e) {
 205       e.preventDefault();
 206       if (e.deltaY < 0) this.undo();
 207       else if (e.deltaY > 0) this.play();
 208     },
 209     redrawBoard: function() {
 210       this.$refs["board"].re_setDrawings();
 211     },
 212     showRules: function() {
 213       // The button is here only on Game page:
 214       document.getElementById("modalRules").checked = true;
 215     },
 216     re_setVariables: function(game) {
 217       if (!game) game = this.game; //in case of...
 218       this.endgameMessage = "";
 219       // "w": default orientation for observed games
 220       this.orientation = game.mycolor || "w";
 221       this.mode = game.mode || game.type; //TODO: merge...
 222       this.moves = JSON.parse(JSON.stringify(game.moves || []));
 223       // Post-processing: decorate each move with notation and FEN
 224       this.vr = new V(game.fenStart);
 225       this.inMultimove = false; //in case of
 226       if (!!this.$refs["board"])
 227         // Also in case of:
 228         this.$refs["board"].resetCurrentAttempt();
 229       let analyseBtn = document.getElementById("analyzeBtn");
 230       if (!!analyseBtn) analyseBtn.classList.remove("active");
 231       const parsedFen = V.ParseFen(game.fenStart);
 232       const firstMoveColor = parsedFen.turn;
 233       this.firstMoveNumber = Math.floor(parsedFen.movesCount / 2) + 1;
 234       let L = this.moves.length;
 235       this.moves.forEach((move,idx) => {
 236         // Strategy working also for multi-moves:
 237         if (!Array.isArray(move)) move = [move];
 238         move.forEach(m => {
 239           m.notation = this.vr.getNotation(m);
 240           m.unambiguous = V.GetUnambiguousNotation(m);
 241           this.vr.play(m);
 242         });
 243         const Lm = move.length;
 244         move[Lm - 1].fen = this.vr.getFen();
 245         if (idx < L - 1 && this.vr.getCheckSquares().length > 0)
 246           move[Lm - 1].notation += "+";
 247       });
 248       this.incheck = this.vr.getCheckSquares();
 249       this.score = this.vr.getCurrentScore();
 250       if (L >= 1) {
 251         const move =
 252           !Array.isArray(this.moves[L - 1])
 253             ? [this.moves[L - 1]]
 254             : this.moves[L - 1];
 255         const Lm = move.length;
 256         if (["1-0", "0-1"].includes(this.score)) move[Lm - 1].notation += "#";
 257         else if (this.incheck.length > 0) move[Lm - 1].notation += "+";
 258       }
 259       if (this.score != '*') {
 260         // Show score on screen
 261         const message = getScoreMessage(this.score);
 262         this.showEndgameMsg(this.score + " . " + this.st.tr[message]);
 263       }
 264       if (firstMoveColor == "b") {
 265         // 'start' & 'end' is required for Board component
 266         this.moves.unshift({
 267           notation: "...",
 268           unambiguous: "...",
 269           start: { x: -1, y: -1 },
 270           end: { x: -1, y: -1 },
 271           fen: game.fenStart
 272         });
 273         L++;
 274       }
 275       this.positionCursorTo(L - 1);
 276     },
 277     positionCursorTo: function(index) {
 278       this.cursor = index;
 279       // Note: last move in moves array might be a multi-move
 280       if (index >= 0) this.lastMove = this.moves[index];
 281       else this.lastMove = null;
 282     },
 283     toggleAnalyze: function() {
 284       // Freeze while choices are shown (and autoplay has priority)
 285       if (
 286         this.inPlay ||
 287         this.$refs["board"].choices.length > 0 ||
 288         this.autoplay
 289       ) {
 290         return;
 291       }
 292       if (this.mode != "analyze") {
 293         // Enter analyze mode:
 294         this.gameMode = this.mode; //was not 'analyze'
 295         this.mode = "analyze";
 296         if (this.inMultimove) this.cancelCurrentMultimove();
 297         this.gameCursor = this.cursor;
 298         this.gameMoves = JSON.parse(JSON.stringify(this.moves));
 299         document.getElementById("analyzeBtn").classList.add("active");
 300       }
 301       else {
 302         // Exit analyze mode:
 303         this.mode = this.gameMode;
 304         this.cursor = this.gameCursor;
 305         this.moves = this.gameMoves;
 306         let fen = this.game.fenStart;
 307         if (this.cursor >= 0) {
 308           let mv = this.moves[this.cursor];
 309           if (!Array.isArray(mv)) mv = [mv];
 310           fen = mv[mv.length-1].fen;
 311         }
 312         this.vr = new V(fen);
 313         this.inMultimove = false; //in case of
 314         this.$refs["board"].resetCurrentAttempt(); //also in case of
 315         this.incheck = this.vr.getCheckSquares();
 316         if (this.cursor >= 0) this.lastMove = this.moves[this.cursor];
 317         else this.lastMove = null;
 318         document.getElementById("analyzeBtn").classList.remove("active");
 319       }
 320     },
 321     download: function() {
 322       const content = this.getPgn();
 323       // Prepare and trigger download link
 324       let downloadAnchor = document.getElementById("download");
 325       downloadAnchor.setAttribute("download", "game.pgn");
 326       downloadAnchor.href =
 327         "data:text/plain;charset=utf-8," + encodeURIComponent(content);
 328       downloadAnchor.click();
 329     },
 330     getPgn: function() {
 331       let pgn = "";
 332       pgn += '[Site "vchess.club"]\n';
 333       pgn += '[Variant "' + this.game.vname + '"]\n';
 334       const gdt = getDate(new Date(this.game.created || Date.now()));
 335       pgn += '[Date "' + gdt + '"]\n';
 336       pgn += '[White "' + this.game.players[0].name + '"]\n';
 337       pgn += '[Black "' + this.game.players[1].name + '"]\n';
 338       pgn += '[Fen "' + this.game.fenStart + '"]\n';
 339       pgn += '[Result "' + this.game.score + '"]\n';
 340       if (!!this.game.id)
 341         pgn += '[Url "' + params.serverUrl + '/game/' + this.game.id + '"]\n';
 342       if (!!this.game.cadence)
 343         pgn += '[Cadence "' + this.game.cadence + '"]\n';
 344       pgn += '[Options "' + JSON.stringify(this.game.options) + '"]\n';
 345       pgn += '\n';
 346       for (let i = 0; i < this.moves.length; i += 2) {
 347         if (i > 0) pgn += " ";
 348         // Adjust dots notation for a better display:
 349         let fullNotation = getFullNotation(this.moves[i]);
 350         if (fullNotation == "...") fullNotation = "..";
 351         pgn += (i / 2 + this.firstMoveNumber) + "." + fullNotation;
 352         if (i+1 < this.moves.length)
 353           pgn += " " + getFullNotation(this.moves[i+1]);
 354       }
 355       pgn += "\n\n";
 356       for (let i = 0; i < this.moves.length; i += 2) {
 357         const moveNumber = i / 2 + this.firstMoveNumber;
 358         // Skip "dots move", useless for machine reading:
 359         if (this.moves[i].notation != "...") {
 360           pgn += moveNumber + ".w " +
 361             getFullNotation(this.moves[i], "unambiguous") + "\n";
 362         }
 363         if (i+1 < this.moves.length) {
 364           pgn += moveNumber + ".b " +
 365             getFullNotation(this.moves[i+1], "unambiguous") + "\n";
 366         }
 367       }
 368       return pgn;
 369     },
 370     showEndgameMsg: function(message) {
 371       this.endgameMessage = message;
 372       document.getElementById("modalEog").checked = true;
 373     },
 374     runAutoplay: function() {
 375       if (this.autoplay) {
 376         this.autoplay = false;
 377         if (this.stackToPlay.length > 0)
 378           // Move(s) arrived in-between
 379           this.play(this.stackToPlay.pop(), "received");
 380       }
 381       else if (this.cursor < this.moves.length - 1) {
 382         this.autoplay = true;
 383         this.play(null, null, null, "autoplay");
 384       }
 385     },
 386     // Animate an elementary move
 387     animateMove: function(move, callback) {
 388       let startSquare = document.getElementById(getSquareId(move.start));
 389       if (!startSquare) return; //shouldn't happen but...
 390       let endSquare = document.getElementById(getSquareId(move.end));
 391       let rectStart = startSquare.getBoundingClientRect();
 392       let rectEnd = endSquare.getBoundingClientRect();
 393       let translation = {
 394         x: rectEnd.x - rectStart.x,
 395         y: rectEnd.y - rectStart.y
 396       };
 397       let movingPiece = document.querySelector(
 398         "#" + getSquareId(move.start) + " > img.piece"
 399       );
 400       // For some unknown reasons Opera get "movingPiece == null" error
 401       // TODO: is it calling 'animate()' twice ? One extra time ?
 402       if (!movingPiece) return;
 403       const squares = document.getElementsByClassName("board");
 404       for (let i = 0; i < squares.length; i++) {
 405         let square = squares.item(i);
 406         if (square.id != getSquareId(move.start))
 407           // HACK for animation:
 408           // (with positive translate, image slides "under background")
 409           square.style.zIndex = "-1";
 410       }
 411       movingPiece.style.transform =
 412         "translate(" + translation.x + "px," + translation.y + "px)";
 413       movingPiece.style.transitionDuration = "0.25s";
 414       movingPiece.style.zIndex = "3000";
 415       setTimeout(() => {
 416         for (let i = 0; i < squares.length; i++)
 417           squares.item(i).style.zIndex = "auto";
 418         movingPiece.style = {}; //required e.g. for 0-0 with KR swap
 419         callback();
 420       }, 250);
 421     },
 422     // For Analyse mode:
 423     emitFenIfAnalyze: function() {
 424       if (this.game.mode == "analyze") {
 425         let fen = this.game.fenStart;
 426         if (!!this.lastMove) {
 427           if (Array.isArray(this.lastMove)) {
 428             const L = this.lastMove.length;
 429             fen = this.lastMove[L-1].fen;
 430           }
 431           else fen = this.lastMove.fen;
 432         }
 433         this.$emit("fenchange", fen);
 434       }
 435     },
 436     clickSquare: function(square) {
 437       // Some variants make use of a single click at specific times:
 438       const move_s = this.vr.doClick(square);
 439       if (!!move_s) {
 440         const playMove = () => {
 441           if (!Array.isArray(move_s)) this.play(move_s);
 442           else this.$refs["board"].choices = move_s;
 443         }
 444         if ("ontouchstart" in window) {
 445           const squareId = "sq-" + square[0] + "-" + square[1];
 446           const highlight = function(on, sq) {
 447             let elt = document.getElementById(sq);
 448             if (!!elt) {
 449               if (on) elt.classList.add("touch-hover");
 450               else elt.classList.remove("touch-hover");
 451             }
 452           }
 453           // Touch screen (smartphone): require confirmation
 454           const squareStr = square[0] + "_" + square[1]
 455           if (this.touchLastClick == squareId) {
 456             highlight(false, squareId);
 457             playMove();
 458           }
 459           else {
 460             highlight(true, squareId);
 461             highlight(false, this.touchLastClick);
 462           }
 463           this.touchLastClick = squareId;
 464         }
 465         else playMove();
 466       }
 467     },
 468     // "light": if gotoMove() or gotoEnd()
 469     play: function(move, received, light, autoplay) {
 470       // Freeze while choices are shown:
 471       if (
 472         !!this.$refs["board"].selectedPiece ||
 473         this.$refs["board"].choices.length > 0
 474       ) {
 475         return;
 476       }
 477       const navigate = !move;
 478       // Forbid navigation during autoplay:
 479       if (navigate && this.autoplay && !autoplay) return;
 480       // Forbid playing outside analyze mode, except if move is received.
 481       // Sufficient condition because Board already knows which turn it is.
 482       if (
 483         this.mode != "analyze" &&
 484         !navigate &&
 485         !received &&
 486         (this.game.score != "*" || this.cursor < this.moves.length - 1)
 487       ) {
 488         return;
 489       }
 490       if (!!received) {
 491         if (this.autoplay || this.inPlay) {
 492           // Received moves while autoplaying are stacked,
 493           // and in observed games they could arrive too fast:
 494           this.stackToPlay.unshift(move);
 495           return;
 496         }
 497         if (this.mode == "analyze") this.toggleAnalyze();
 498         if (this.cursor < this.moves.length - 1)
 499           // To play a received move, cursor must be at the end of the game:
 500           this.gotoEnd();
 501         this.inPlay = true;
 502       }
 503       // The board may show some possible moves: (TODO: bad solution)
 504       this.$refs["board"].resetCurrentAttempt();
 505       const playSubmove = (smove) => {
 506         smove.notation = this.vr.getNotation(smove);
 507         smove.unambiguous = V.GetUnambiguousNotation(smove);
 508         this.vr.play(smove);
 509         if (this.inMultimove && !!this.lastMove) {
 510           if (!Array.isArray(this.lastMove))
 511             this.lastMove = [this.lastMove, smove];
 512           else this.lastMove.push(smove);
 513         }
 514         if (!this.inMultimove) {
 515           // First sub-move:
 516           this.lastMove = smove;
 517           // Condition is "!navigate" but we mean "!this.autoplay"
 518           if (!navigate) {
 519             if (this.cursor < this.moves.length - 1)
 520               this.moves = this.moves.slice(0, this.cursor + 1);
 521             this.moves.push(smove);
 522           }
 523           this.inMultimove = true; //potentially
 524           this.cursor++;
 525         }
 526         else if (!navigate) {
 527           // Already in the middle of a multi-move
 528           const L = this.moves.length;
 529           if (!Array.isArray(this.moves[L-1]))
 530             this.$set(this.moves, L-1, [this.moves[L-1], smove]);
 531           else this.moves[L-1].push(smove);
 532         }
 533       };
 534       const playMove = () => {
 535         const animate = (
 536           ["all", "highlight"].includes(V.ShowMoves) &&
 537           (this.autoplay || !!received)
 538         );
 539         if (!Array.isArray(move)) move = [move];
 540         let moveIdx = 0;
 541         let self = this;
 542         const initurn = this.vr.turn;
 543         (function executeMove() {
 544           const smove = move[moveIdx++];
 545           // NOTE: condition "smove.start.x >= 0" required for Dynamo,
 546           // because second move may be empty. noHighlight condition
 547           // is used at least for Chakart.
 548           if (animate && smove.start.x >= 0 && !smove.end.noHighlight) {
 549             self.animateMove(smove, () => {
 550               playSubmove(smove);
 551               if (moveIdx < move.length) setTimeout(executeMove, 500);
 552               else afterMove(smove, initurn);
 553             });
 554           }
 555           else {
 556             playSubmove(smove);
 557             if (moveIdx < move.length) executeMove();
 558             else afterMove(smove, initurn);
 559           }
 560         })();
 561       };
 562       const computeScore = () => {
 563         const score = this.vr.getCurrentScore();
 564         if (!navigate) {
 565           if (["1-0", "0-1"].includes(score)) {
 566             if (Array.isArray(this.lastMove)) {
 567               const L = this.lastMove.length;
 568               this.lastMove[L - 1].notation += "#";
 569             }
 570             else this.lastMove.notation += "#";
 571           }
 572         }
 573         if (score != "*" && ["analyze", "versus"].includes(this.mode)) {
 574           const message = getScoreMessage(score, V.ReverseColors);
 575           // Show score on screen
 576           this.showEndgameMsg(score + " . " + this.st.tr[message]);
 577         }
 578         return score;
 579       };
 580       const afterMove = (smove, initurn) => {
 581         if (this.vr.turn != initurn) {
 582           // Turn has changed: move is complete
 583           if (!smove.fen)
 584             // NOTE: only FEN of last sub-move is required (=> setting it here)
 585             smove.fen = this.vr.getFen();
 586           this.emitFenIfAnalyze();
 587           this.inMultimove = false;
 588           this.incheck = this.vr.getCheckSquares();
 589           if (this.incheck.length > 0) smove.notation += "+";
 590           this.score = computeScore();
 591           if (this.autoplay) {
 592             if (this.cursor < this.moves.length - 1)
 593               setTimeout(() => this.play(null, null, null, "autoplay"), 1000);
 594             else {
 595               this.autoplay = false;
 596               if (this.stackToPlay.length > 0)
 597                 // Move(s) arrived in-between
 598                 this.play(this.stackToPlay.pop(), "received");
 599             }
 600           }
 601           if (this.mode != "analyze" && !navigate) {
 602             if (!received) {
 603               // Post-processing (e.g. computer play).
 604               const L = this.moves.length;
 605               // NOTE: always emit the score, even in unfinished
 606               this.$emit("newmove", this.moves[L-1], { score: this.score });
 607             }
 608             else {
 609               this.inPlay = false;
 610               if (this.stackToPlay.length > 0)
 611                 // Move(s) arrived in-between
 612                 this.play(this.stackToPlay.pop(), "received");
 613             }
 614           }
 615         }
 616       };
 617       // NOTE: navigate and received are mutually exclusive
 618       if (navigate) {
 619         // The move to navigate to is necessarily full:
 620         if (this.cursor == this.moves.length - 1) return; //no more moves
 621         move = this.moves[this.cursor + 1];
 622         if (!this.autoplay) {
 623           // Just play the move:
 624           if (!Array.isArray(move)) move = [move];
 625           for (let i=0; i < move.length; i++) this.vr.play(move[i]);
 626           if (!light) {
 627             this.lastMove = move;
 628             this.incheck = this.vr.getCheckSquares();
 629             this.score = computeScore();
 630             this.emitFenIfAnalyze();
 631           }
 632           this.cursor++;
 633           return;
 634         }
 635       }
 636       playMove();
 637     },
 638     cancelCurrentMultimove: function() {
 639       const L = this.moves.length;
 640       let move = this.moves[L-1];
 641       if (!Array.isArray(move)) move = [move];
 642       for (let i = move.length - 1; i >= 0; i--) this.vr.undo(move[i]);
 643       this.moves.pop();
 644       this.cursor--;
 645       this.inMultimove = false;
 646     },
 647     cancelLastMove: function() {
 648       // The last played move was canceled (corr game)
 649       this.undo();
 650       this.moves.pop();
 651     },
 652     // "light": if gotoMove() or gotoBegin()
 653     undo: function(move, light) {
 654       if (
 655         this.autoplay ||
 656         !!this.$refs["board"].selectedPiece ||
 657         this.$refs["board"].choices.length > 0
 658       ) {
 659         return;
 660       }
 661       this.$refs["board"].resetCurrentAttempt();
 662       if (this.inMultimove) {
 663         this.cancelCurrentMultimove();
 664         this.incheck = this.vr.getCheckSquares();
 665         if (this.cursor >= 0) this.lastMove = this.moves[this.cursor];
 666         else this.lastMove = null;
 667       }
 668       else {
 669         if (!move) {
 670           const minCursor =
 671             this.moves.length > 0 && this.moves[0].notation == "..."
 672               ? 1
 673               : 0;
 674           if (this.cursor < minCursor) return; //no more moves
 675           move = this.moves[this.cursor];
 676         }
 677         this.$refs["board"].resetCurrentAttempt();
 678         undoMove(move, this.vr);
 679         if (light) this.cursor--;
 680         else {
 681           this.positionCursorTo(this.cursor - 1);
 682           this.incheck = this.vr.getCheckSquares();
 683           this.emitFenIfAnalyze();
 684         }
 685       }
 686     },
 687     gotoMove: function(index) {
 688       if (
 689         this.autoplay ||
 690         !!this.$refs["board"].selectedPiece ||
 691         this.$refs["board"].choices.length > 0
 692       ) {
 693         return;
 694       }
 695       this.$refs["board"].resetCurrentAttempt();
 696       if (this.inMultimove) this.cancelCurrentMultimove();
 697       if (index == this.cursor) return;
 698       if (index < this.cursor) {
 699         while (this.cursor > index)
 700           this.undo(null, null, "light");
 701       }
 702       else {
 703         // index > this.cursor)
 704         while (this.cursor < index)
 705           this.play(null, null, "light");
 706       }
 707       // NOTE: next line also re-assign cursor, but it's very light
 708       this.positionCursorTo(index);
 709       this.incheck = this.vr.getCheckSquares();
 710       this.emitFenIfAnalyze();
 711     },
 712     gotoBegin: function() {
 713       if (
 714         this.autoplay ||
 715         !!this.$refs["board"].selectedPiece ||
 716         this.$refs["board"].choices.length > 0
 717       ) {
 718         return;
 719       }
 720       this.$refs["board"].resetCurrentAttempt();
 721       if (this.inMultimove) this.cancelCurrentMultimove();
 722       const minCursor =
 723         this.moves.length > 0 && this.moves[0].notation == "..."
 724           ? 1
 725           : 0;
 726       while (this.cursor >= minCursor) this.undo(null, null, "light");
 727       this.lastMove = (minCursor == 1 ? this.moves[0] : null);
 728       this.incheck = this.vr.getCheckSquares();
 729       this.emitFenIfAnalyze();
 730     },
 731     gotoEnd: function() {
 732       if (this.cursor == this.moves.length - 1) return;
 733       this.gotoMove(this.moves.length - 1);
 734     },
 735     flip: function() {
 736       if (this.$refs["board"].choices.length > 0) return;
 737       this.orientation = V.GetOppCol(this.orientation);
 738     }
 739   }
 740 };
 741 </script>
 742
 743 <style lang="sass" scoped>
 744 [type="checkbox"]#modalEog+div .card
 745   min-height: 45px
 746   max-width: 350px
 747
 748 #baseGame
 749   width: 100%
 750   &:focus
 751     outline: none
 752
 753 #gameContainer
 754   margin-left: auto
 755   margin-right: auto
 756
 757 #downloadDiv
 758   display: inline-block
 759
 760 #controls
 761   user-select: none
 762   button
 763     border: none
 764     margin: 0
 765     padding-top: 5px
 766     padding-bottom: 5px
 767
 768 p#fenAnalyze
 769   margin: 5px
 770
 771 .in-autoplay
 772   background-color: #FACF8C
 773
 774 img.inline
 775   height: 22px
 776   padding-top: 5px
 777   @media screen and (max-width: 767px)
 778     height: 18px
 779
 780 #turnIndicator
 781   text-align: center
 782   font-weight: bold
 783
 784 #boardContainer
 785   float: left
 786 // TODO: later, maybe, allow movesList of variable width
 787 // or e.g. between 250 and 350px (but more complicated)
 788
 789 #movesList
 790   width: 280px
 791   float: left
 792
 793 @media screen and (max-width: 767px)
 794   #movesList
 795     width: 100%
 796     float: none
 797     clear: both
 798 </style>