Almost finished problems logic. TODO: showProblem() part

[vchess.git] / public / javascripts / components / game.js

// Game logic on a variant page
Vue.component('my-game', {
    data: function() {
        return {
            vr: null, //object to check moves, store them, FEN..
            mycolor: "w",
            possibleMoves: [], //filled after each valid click/dragstart
            choices: [], //promotion pieces, or checkered captures... (as moves)
            start: {}, //pixels coordinates + id of starting square (click or drag)
            selectedPiece: null, //moving piece (or clicked piece)
            conn: null, //socket connection
            score: "*", //'*' means 'unfinished'
            mode: "idle", //human, friend, computer or idle (when not playing)
            oppid: "", //opponent ID in case of HH game
            oppConnected: false,
            seek: false,
            fenStart: "",
            incheck: [],
            pgnTxt: "",
            hints: (getCookie("hints") === "1" ? true : false),
            color: getCookie("color", "lichess"), //lichess, chesscom or chesstempo
            // sound level: 0 = no sound, 1 = sound only on newgame, 2 = always
            sound: parseInt(getCookie("sound", "2")),
        };
    },
    render(h) {
        const [sizeX,sizeY] = [V.size.x,V.size.y];
        const smallScreen = (window.innerWidth <= 420);
        // Precompute hints squares to facilitate rendering
        let hintSquares = doubleArray(sizeX, sizeY, false);
        this.possibleMoves.forEach(m => { hintSquares[m.end.x][m.end.y] = true; });
        // Also precompute in-check squares
        let incheckSq = doubleArray(sizeX, sizeY, false);
        this.incheck.forEach(sq => { incheckSq[sq[0]][sq[1]] = true; });
        let elementArray = [];
        let actionArray = [];
        actionArray.push(
            h('button',
            {
                on: { click: this.clickGameSeek },
                attrs: { "aria-label": 'New online game' },
                'class': {
                    "tooltip": true,
                    "bottom": true, //display below
                    "seek": this.seek,
                    "playing": this.mode == "human",
                    "small": smallScreen,
                },
            },
            [h('i', { 'class': { "material-icons": true } }, "accessibility")])
        );
        if (["idle","computer"].includes(this.mode))
        {
            actionArray.push(
                h('button',
                {
                    on: { click: this.clickComputerGame },
                    attrs: { "aria-label": 'New game VS computer' },
                    'class': {
                        "tooltip":true,
                        "bottom": true,
                        "playing": this.mode == "computer",
                        "small": smallScreen,
                    },
                },
                [h('i', { 'class': { "material-icons": true } }, "computer")])
            );
        }
        if (["idle","friend"].includes(this.mode))
        {
            actionArray.push(
                h('button',
                {
                    on: { click: this.clickFriendGame },
                    attrs: { "aria-label": 'New IRL game' },
                    'class': {
                        "tooltip":true,
                        "bottom": true,
                        "playing": this.mode == "friend",
                        "small": smallScreen,
                    },
                },
                [h('i', { 'class': { "material-icons": true } }, "people")])
            );
        }
        if (!!this.vr)
        {
            const square00 = document.getElementById("sq-0-0");
            const squareWidth = !!square00
                ? parseFloat(window.getComputedStyle(square00).width.slice(0,-2))
                : 0;
            const settingsBtnElt = document.getElementById("settingsBtn");
            const indicWidth = !!settingsBtnElt //-2 for border:
                ? parseFloat(window.getComputedStyle(settingsBtnElt).height.slice(0,-2)) - 2
                : (smallScreen ? 31 : 37);
            if (this.mode == "human")
            {
                let connectedIndic = h(
                    'div',
                    {
                        "class": {
                            "topindicator": true,
                            "indic-left": true,
                            "connected": this.oppConnected,
                            "disconnected": !this.oppConnected,
                        },
                        style: {
                            "width": indicWidth + "px",
                            "height": indicWidth + "px",
                        },
                    }
                );
                elementArray.push(connectedIndic);
            }
            let turnIndic = h(
                'div',
                {
                    "class": {
                        "topindicator": true,
                        "indic-right": true,
                        "white-turn": this.vr.turn=="w",
                        "black-turn": this.vr.turn=="b",
                    },
                    style: {
                        "width": indicWidth + "px",
                        "height": indicWidth + "px",
                    },
                }
            );
            elementArray.push(turnIndic);
            let settingsBtn = h(
                'button',
                {
                    on: { click: this.showSettings },
                    attrs: {
                        "aria-label": 'Settings',
                        "id": "settingsBtn",
                    },
                    'class': {
                        "tooltip": true,
                        "topindicator": true,
                        "indic-right": true,
                        "settings-btn": !smallScreen,
                        "settings-btn-small": smallScreen,
                    },
                },
                [h('i', { 'class': { "material-icons": true } }, "settings")]
            );
            elementArray.push(settingsBtn);
            let choices = h('div',
                {
                    attrs: { "id": "choices" },
                    'class': { 'row': true },
                    style: {
                        "display": this.choices.length>0?"block":"none",
                        "top": "-" + ((sizeY/2)*squareWidth+squareWidth/2) + "px",
                        "width": (this.choices.length * squareWidth) + "px",
                        "height": squareWidth + "px",
                    },
                },
                this.choices.map( m => { //a "choice" is a move
                    return h('div',
                        {
                            'class': {
                                'board': true,
                                ['board'+sizeY]: true,
                            },
                            style: {
                                'width': (100/this.choices.length) + "%",
                                'padding-bottom': (100/this.choices.length) + "%",
                            },
                        },
                        [h('img',
                            {
                                attrs: { "src": '/images/pieces/' +
                                    VariantRules.getPpath(m.appear[0].c+m.appear[0].p) + '.svg' },
                                'class': { 'choice-piece': true },
                                on: { "click": e => { this.play(m); this.choices=[]; } },
                            })
                        ]
                    );
                })
            );
            // Create board element (+ reserves if needed by variant or mode)
            const lm = this.vr.lastMove;
            const showLight = this.hints &&
                (this.mode!="idle" || this.cursor==this.vr.moves.length);
            let gameDiv = h('div',
                {
                    'class': { 'game': true },
                },
                [_.range(sizeX).map(i => {
                    let ci = this.mycolor=='w' ? i : sizeX-i-1;
                    return h(
                        'div',
                        {
                            'class': {
                                'row': true,
                            },
                            style: { 'opacity': this.choices.length>0?"0.5":"1" },
                        },
                        _.range(sizeY).map(j => {
                            let cj = this.mycolor=='w' ? j : sizeY-j-1;
                            let elems = [];
                            if (this.vr.board[ci][cj] != VariantRules.EMPTY)
                            {
                                elems.push(
                                    h(
                                        'img',
                                        {
                                            'class': {
                                                'piece': true,
                                                'ghost': !!this.selectedPiece
                                                    && this.selectedPiece.parentNode.id == "sq-"+ci+"-"+cj,
                                            },
                                            attrs: {
                                                src: "/images/pieces/" +
                                                    VariantRules.getPpath(this.vr.board[ci][cj]) + ".svg",
                                            },
                                        }
                                    )
                                );
                            }
                            if (this.hints && hintSquares[ci][cj])
                            {
                                elems.push(
                                    h(
                                        'img',
                                        {
                                            'class': {
                                                'mark-square': true,
                                            },
                                            attrs: {
                                                src: "/images/mark.svg",
                                            },
                                        }
                                    )
                                );
                            }
                            return h(
                                'div',
                                {
                                    'class': {
                                        'board': true,
                                        ['board'+sizeY]: true,
                                        'light-square': (i+j)%2==0,
                                        'dark-square': (i+j)%2==1,
                                        [this.color]: true,
                                        'highlight': showLight && !!lm && _.isMatch(lm.end, {x:ci,y:cj}),
                                        'incheck': showLight && incheckSq[ci][cj],
                                    },
                                    attrs: {
                                        id: this.getSquareId({x:ci,y:cj}),
                                    },
                                },
                                elems
                            );
                        })
                    );
                }), choices]
            );
            if (this.mode != "idle")
            {
                actionArray.push(
                    h('button',
                        {
                            on: { click: this.resign },
                            attrs: { "aria-label": 'Resign' },
                            'class': {
                                "tooltip":true,
                                "bottom": true,
                                "small": smallScreen,
                            },
                        },
                        [h('i', { 'class': { "material-icons": true } }, "flag")])
                );
            }
            else if (this.vr.moves.length > 0)
            {
                // A game finished, and another is not started yet: allow navigation
                actionArray = actionArray.concat([
                    h('button',
                        {
                            on: { click: e => this.undo() },
                            attrs: { "aria-label": 'Undo' },
                            "class": {
                                "small": smallScreen,
                                "marginleft": true,
                            },
                        },
                        [h('i', { 'class': { "material-icons": true } }, "fast_rewind")]),
                    h('button',
                        {
                            on: { click: e => this.play() },
                            attrs: { "aria-label": 'Play' },
                            "class": { "small": smallScreen },
                        },
                        [h('i', { 'class': { "material-icons": true } }, "fast_forward")]),
                    ]
                );
            }
            if (this.mode == "friend")
            {
                actionArray = actionArray.concat(
                [
                    h('button',
                        {
                            on: { click: this.undoInGame },
                            attrs: { "aria-label": 'Undo' },
                            "class": {
                                "small": smallScreen,
                                "marginleft": true,
                            },
                        },
                        [h('i', { 'class': { "material-icons": true } }, "undo")]
                    ),
                    h('button',
                        {
                            on: { click: () => { this.mycolor = this.vr.getOppCol(this.mycolor) } },
                            attrs: { "aria-label": 'Flip' },
                            "class": { "small": smallScreen },
                        },
                        [h('i', { 'class': { "material-icons": true } }, "cached")]
                    ),
                ]);
            }
            elementArray.push(gameDiv);
            if (!!this.vr.reserve)
            {
                const shiftIdx = (this.mycolor=="w" ? 0 : 1);
                let myReservePiecesArray = [];
                for (let i=0; i<VariantRules.RESERVE_PIECES.length; i++)
                {
                    myReservePiecesArray.push(h('div',
                    {
                        'class': {'board':true, ['board'+sizeY]:true},
                        attrs: { id: this.getSquareId({x:sizeX+shiftIdx,y:i}) }
                    },
                    [
                        h('img',
                        {
                            'class': {"piece":true},
                            attrs: {
                                "src": "/images/pieces/" +
                                    this.vr.getReservePpath(this.mycolor,i) + ".svg",
                            }
                        }),
                        h('sup',
                            {"class": { "reserve-count": true } },
                            [ this.vr.reserve[this.mycolor][VariantRules.RESERVE_PIECES[i]] ]
                        )
                    ]));
                }
                let oppReservePiecesArray = [];
                const oppCol = this.vr.getOppCol(this.mycolor);
                for (let i=0; i<VariantRules.RESERVE_PIECES.length; i++)
                {
                    oppReservePiecesArray.push(h('div',
                    {
                        'class': {'board':true, ['board'+sizeY]:true},
                        attrs: { id: this.getSquareId({x:sizeX+(1-shiftIdx),y:i}) }
                    },
                    [
                        h('img',
                        {
                            'class': {"piece":true},
                            attrs: {
                                "src": "/images/pieces/" +
                                    this.vr.getReservePpath(oppCol,i) + ".svg",
                            }
                        }),
                        h('sup',
                            {"class": { "reserve-count": true } },
                            [ this.vr.reserve[oppCol][VariantRules.RESERVE_PIECES[i]] ]
                        )
                    ]));
                }
                let reserves = h('div',
                    {
                        'class':{
                            'game': true,
                            "reserve-div": true,
                        },
                    },
                    [
                        h('div',
                            {
                                'class': {
                                    'row': true,
                                    "reserve-row-1": true,
                                },
                            },
                            myReservePiecesArray
                        ),
                        h('div',
                            { 'class': { 'row': true }},
                            oppReservePiecesArray
                        )
                    ]
                );
                elementArray.push(reserves);
            }
            const eogMessage = this.getEndgameMessage(this.score);
            const modalEog = [
                h('input',
                    {
                        attrs: { "id": "modal-eog", type: "checkbox" },
                        "class": { "modal": true },
                    }),
                h('div',
                    {
                        attrs: { "role": "dialog", "aria-labelledby": "eogMessage" },
                    },
                    [
                        h('div',
                            {
                                "class": { "card": true, "smallpad": true },
                            },
                            [
                                h('label',
                                    {
                                        attrs: { "for": "modal-eog" },
                                        "class": { "modal-close": true },
                                    }
                                ),
                                h('h3',
                                    {
                                        attrs: { "id": "eogMessage" },
                                        "class": { "section": true },
                                        domProps: { innerHTML: eogMessage },
                                    }
                                )
                            ]
                        )
                    ]
                )
            ];
            elementArray = elementArray.concat(modalEog);
        }
        // NOTE: this modal could be in Pug view (no usage of Vue functions or variables)
        const modalNewgame = [
            h('input',
                {
                    attrs: { "id": "modal-newgame", type: "checkbox" },
                    "class": { "modal": true },
                }),
            h('div',
                {
                    attrs: { "role": "dialog", "aria-labelledby": "newGameTxt" },
                },
                [
                    h('div',
                        {
                            "class": { "card": true, "smallpad": true },
                        },
                        [
                            h('label',
                                {
                                    attrs: { "id": "close-newgame", "for": "modal-newgame" },
                                    "class": { "modal-close": true },
                                }
                            ),
                            h('h3',
                                {
                                    attrs: { "id": "newGameTxt" },
                                    "class": { "section": true },
                                    domProps: { innerHTML: "New game" },
                                }
                            ),
                            h('p',
                                {
                                    "class": { "section": true },
                                    domProps: { innerHTML: "Waiting for opponent..." },
                                }
                            )
                        ]
                    )
                ]
            )
        ];
        elementArray = elementArray.concat(modalNewgame);
        const modalFenEdit = [
            h('input',
                {
                    attrs: { "id": "modal-fenedit", type: "checkbox" },
                    "class": { "modal": true },
                }),
            h('div',
                {
                    attrs: { "role": "dialog", "aria-labelledby": "titleFenedit" },
                },
                [
                    h('div',
                        {
                            "class": { "card": true, "smallpad": true },
                        },
                        [
                            h('label',
                                {
                                    attrs: { "id": "close-fenedit", "for": "modal-fenedit" },
                                    "class": { "modal-close": true },
                                }
                            ),
                            h('h3',
                                {
                                    attrs: { "id": "titleFenedit" },
                                    "class": { "section": true },
                                    domProps: { innerHTML: "Position + flags (FEN):" },
                                }
                            ),
                            h('input',
                                {
                                    attrs: {
                                        "id": "input-fen",
                                        type: "text",
                                        value: VariantRules.GenRandInitFen(),
                                    },
                                }
                            ),
                            h('button',
                                {
                                    on: { click:
                                        () => {
                                            const fen = document.getElementById("input-fen").value;
                                            document.getElementById("modal-fenedit").checked = false;
                                            this.newGame("friend", fen);
                                        }
                                    },
                                    domProps: { innerHTML: "Ok" },
                                }
                            ),
                            h('button',
                                {
                                    on: { click:
                                        () => {
                                            document.getElementById("input-fen").value =
                                                VariantRules.GenRandInitFen();
                                        }
                                    },
                                    domProps: { innerHTML: "Random" },
                                }
                            ),
                        ]
                    )
                ]
            )
        ];
        elementArray = elementArray.concat(modalFenEdit);
        const modalSettings = [
            h('input',
                {
                    attrs: { "id": "modal-settings", type: "checkbox" },
                    "class": { "modal": true },
                }),
            h('div',
                {
                    attrs: { "role": "dialog", "aria-labelledby": "settingsTitle" },
                },
                [
                    h('div',
                        {
                            "class": { "card": true, "smallpad": true },
                        },
                        [
                            h('label',
                                {
                                    attrs: { "id": "close-settings", "for": "modal-settings" },
                                    "class": { "modal-close": true },
                                }
                            ),
                            h('h3',
                                {
                                    attrs: { "id": "settingsTitle" },
                                    "class": { "section": true },
                                    domProps: { innerHTML: "Preferences" },
                                }
                            ),
                            h('fieldset',
                              { },
                                [
                                    //h('legend', { domProps: { innerHTML: "Legend title" } }),
                                    h('label',
                                        {
                                            attrs: { for: "setHints" },
                                            domProps: { innerHTML: "Show hints?" },
                                        },
                                    ),
                                    h('input',
                                        {
                                            attrs: {
                                                "id": "setHints",
                                                type: "checkbox",
                                                checked: this.hints,
                                            },
                                            on: { "change": this.toggleHints },
                                        }
                                    ),
                                ]
                            ),
                            h('fieldset',
                                { },
                                [
                                    h('label',
                                        {
                                            attrs: { for: "selectColor" },
                                            domProps: { innerHTML: "Board colors" },
                                        },
                                    ),
                                    h("select",
                                        {
                                            attrs: { "id": "selectColor" },
                                            on: { "change": this.setColor },
                                        },
                                        [
                                            h("option",
                                                {
                                                    domProps: {
                                                        "value": "lichess",
                                                        innerHTML: "brown"
                                                    },
                                                    attrs: { "selected": this.color=="lichess" },
                                                }
                                            ),
                                            h("option",
                                                {
                                                    domProps: {
                                                        "value": "chesscom",
                                                        innerHTML: "green"
                                                    },
                                                    attrs: { "selected": this.color=="chesscom" },
                                                }
                                            ),
                                            h("option",
                                                {
                                                    domProps: {
                                                        "value": "chesstempo",
                                                        innerHTML: "blue"
                                                    },
                                                    attrs: { "selected": this.color=="chesstempo" },
                                                }
                                            ),
                                        ],
                                    ),
                                ]
                            ),
                            h('fieldset',
                                { },
                                [
                                    h('label',
                                        {
                                            attrs: { for: "selectSound" },
                                            domProps: { innerHTML: "Play sounds?" },
                                        },
                                    ),
                                    h("select",
                                        {
                                            attrs: { "id": "selectSound" },
                                            on: { "change": this.setSound },
                                        },
                                        [
                                            h("option",
                                                {
                                                    domProps: {
                                                        "value": "0",
                                                        innerHTML: "None"
                                                    },
                                                    attrs: { "selected": this.sound==0 },
                                                }
                                            ),
                                            h("option",
                                                {
                                                    domProps: {
                                                        "value": "1",
                                                        innerHTML: "Newgame"
                                                    },
                                                    attrs: { "selected": this.sound==1 },
                                                }
                                            ),
                                            h("option",
                                                {
                                                    domProps: {
                                                        "value": "2",
                                                        innerHTML: "All"
                                                    },
                                                    attrs: { "selected": this.sound==2 },
                                                }
                                            ),
                                        ],
                                    ),
                                ]
                            ),
                        ]
                    )
                ]
            )
        ];
        elementArray = elementArray.concat(modalSettings);
        const actions = h('div',
            {
                attrs: { "id": "actions" },
                'class': { 'text-center': true },
            },
            actionArray
        );
        elementArray.push(actions);
        if (this.score != "*")
        {
            elementArray.push(
                h('div',
                    {
                        attrs: { id: "pgn-div" },
                        "class": { "section-content": true },
                    },
                    [
                        h('a',
                            {
                                attrs: {
                                    id: "download",
                                    href: "#",
                                }
                            }
                        ),
                        h('p',
                            {
                                attrs: { id: "pgn-game" },
                                domProps: { innerHTML: this.pgnTxt }
                            }
                        ),
                        h('button',
                            {
                                attrs: { "id": "downloadBtn" },
                                on: { click: this.download },
                                domProps: { innerHTML: "Download game" },
                            }
                        ),
                    ]
                )
            );
        }
        else if (this.mode != "idle")
        {
            // Show current FEN
            elementArray.push(
                h('div',
                    {
                        attrs: { id: "fen-div" },
                        "class": { "section-content": true },
                    },
                    [
                        h('p',
                            {
                                attrs: { id: "fen-string" },
                                domProps: { innerHTML: this.vr.getFen() }
                            }
                        )
                    ]
                )
            );
        }
        return h(
            'div',
            {
                'class': {
                    "col-sm-12":true,
                    "col-md-8":true,
                    "col-md-offset-2":true,
                    "col-lg-6":true,
                    "col-lg-offset-3":true,
                },
                // NOTE: click = mousedown + mouseup
                on: {
                    mousedown: this.mousedown,
                    mousemove: this.mousemove,
                    mouseup: this.mouseup,
                    touchstart: this.mousedown,
                    touchmove: this.mousemove,
                    touchend: this.mouseup,
                },
            },
            elementArray
        );
    },
    created: function() {
        const url = socketUrl;
        const continuation = (localStorage.getItem("variant") === variant);
        this.myid = (continuation ? localStorage.getItem("myid") : getRandString());
        if (!continuation)
        {
            // HACK: play a small silent sound to allow "new game" sound later
            // if tab not focused (TODO: does it really work ?!)
            new Audio("/sounds/silent.mp3").play().then(() => {}).catch(err => {});
        }
        this.conn = new WebSocket(url + "/?sid=" + this.myid + "&page=" + variant);
        const socketOpenListener = () => {
            if (continuation)
            {
                const fen = localStorage.getItem("fen");
                const mycolor = localStorage.getItem("mycolor");
                const oppid = localStorage.getItem("oppid");
                const moves = JSON.parse(localStorage.getItem("moves"));
                this.newGame("human", fen, mycolor, oppid, moves, true);
                // Send ping to server (answer pong if opponent is connected)
                this.conn.send(JSON.stringify({code:"ping",oppid:this.oppid}));
            }
            else if (localStorage.getItem("newgame") === variant)
            {
                // New game request has been cancelled on disconnect
                this.newGame("human", undefined, undefined, undefined, undefined, "reconnect");
            }
        };
        const socketMessageListener = msg => {
            const data = JSON.parse(msg.data);
            switch (data.code)
            {
                case "duplicate":
                    // We opened another tab on the same game
                    this.mode = "idle";
                    this.vr = null;
                    alert("Already playing a game in this variant on another tab!");
                    break;
                case "newgame": //opponent found
                    // oppid: opponent socket ID
                    this.newGame("human", data.fen, data.color, data.oppid);
                    break;
                case "newmove": //..he played!
                    this.play(data.move, "animate");
                    break;
                case "pong": //received if we sent a ping (game still alive on our side)
                    this.oppConnected = true;
                    const L = this.vr.moves.length;
                    // Send our "last state" informations to opponent
                    this.conn.send(JSON.stringify({
                        code:"lastate",
                        oppid:this.oppid,
                        lastMove:L>0?this.vr.moves[L-1]:undefined,
                        movesCount:L,
                    }));
                    break;
                case "lastate": //got opponent infos about last move (we might have resigned)
                    if (this.mode!="human" || this.oppid!=data.oppid)
                    {
                        // OK, we resigned
                        this.conn.send(JSON.stringify({
                            code:"lastate",
                            oppid:this.oppid,
                            lastMove:undefined,
                            movesCount:-1,
                        }));
                    }
                    else if (data.movesCount < 0)
                    {
                        // OK, he resigned
                        this.endGame(this.mycolor=="w"?"1-0":"0-1");
                    }
                    else if (data.movesCount < this.vr.moves.length)
                    {
                        // We must tell last move to opponent
                        const L = this.vr.moves.length;
                        this.conn.send(JSON.stringify({
                            code:"lastate",
                            oppid:this.oppid,
                            lastMove:this.vr.moves[L-1],
                            movesCount:L,
                        }));
                    }
                    else if (data.movesCount > this.vr.moves.length) //just got last move from him
                        this.play(data.lastMove, "animate");
                    break;
                case "resign": //..you won!
                    this.endGame(this.mycolor=="w"?"1-0":"0-1");
                    break;
                // TODO: also use (dis)connect info to count online players?
                case "connect":
                case "disconnect":
                    if (this.mode == "human" && this.oppid == data.id)
                        this.oppConnected = (data.code == "connect");
                    break;
            }
        };
        const socketCloseListener = () => {
            this.conn = new WebSocket(url + "/?sid=" + this.myid + "&page=" + variant);
            this.conn.addEventListener('open', socketOpenListener);
            this.conn.addEventListener('message', socketMessageListener);
            this.conn.addEventListener('close', socketCloseListener);
        };
        this.conn.onopen = socketOpenListener;
        this.conn.onmessage = socketMessageListener;
        this.conn.onclose = socketCloseListener;
        // Listen to keyboard left/right to navigate in game
        document.onkeydown = event => {
            if (this.mode == "idle" && !!this.vr && this.vr.moves.length > 0
                && [37,39].includes(event.keyCode))
            {
                event.preventDefault();
                if (event.keyCode == 37) //Back
                    this.undo();
                else //Forward (39)
                    this.play();
            }
        };
    },
    methods: {
        download: function() {
            let content = document.getElementById("pgn-game").innerHTML;
            content = content.replace(/<br>/g, "\n");
            // Prepare and trigger download link
            let downloadAnchor = document.getElementById("download");
            downloadAnchor.setAttribute("download", "game.pgn");
            downloadAnchor.href = "data:text/plain;charset=utf-8," +
                encodeURIComponent(content);
            downloadAnchor.click();
        },
        endGame: function(score) {
            this.score = score;
            let modalBox = document.getElementById("modal-eog");
            modalBox.checked = true;
            // Variants may have special PGN structure (so next function isn't defined here)
            this.pgnTxt = this.vr.getPGN(this.mycolor, this.score, this.fenStart, this.mode);
            setTimeout(() => { modalBox.checked = false; }, 2000);
            if (this.mode == "human")
                this.clearStorage();
            this.mode = "idle";
            this.cursor = this.vr.moves.length; //to navigate in finished game
            this.oppid = "";
        },
        getEndgameMessage: function(score) {
            let eogMessage = "Unfinished";
            switch (this.score)
            {
                case "1-0":
                    eogMessage = "White win";
                    break;
                case "0-1":
                    eogMessage = "Black win";
                    break;
                case "1/2":
                    eogMessage = "Draw";
                    break;
            }
            return eogMessage;
        },
        setStorage: function() {
            localStorage.setItem("myid", this.myid);
            localStorage.setItem("variant", variant);
            localStorage.setItem("mycolor", this.mycolor);
            localStorage.setItem("oppid", this.oppid);
            localStorage.setItem("fenStart", this.fenStart);
            localStorage.setItem("moves", JSON.stringify(this.vr.moves));
            localStorage.setItem("fen", this.vr.getFen());
        },
        updateStorage: function() {
            localStorage.setItem("moves", JSON.stringify(this.vr.moves));
            localStorage.setItem("fen", this.vr.getFen());
        },
        clearStorage: function() {
            delete localStorage["variant"];
            delete localStorage["myid"];
            delete localStorage["mycolor"];
            delete localStorage["oppid"];
            delete localStorage["fenStart"];
            delete localStorage["fen"];
            delete localStorage["moves"];
        },
        // HACK because mini-css tooltips are persistent after click...
        getRidOfTooltip: function(elt) {
            elt.style.visibility = "hidden";
            setTimeout(() => { elt.style.visibility="visible"; }, 100);
        },
        showSettings: function(e) {
            this.getRidOfTooltip(e.currentTarget);
            document.getElementById("modal-settings").checked = true;
        },
        toggleHints: function() {
            this.hints = !this.hints;
            setCookie("hints", this.hints ? "1" : "0");
        },
        setColor: function(e) {
            this.color = e.target.options[e.target.selectedIndex].value;
            setCookie("color", this.color);
        },
        setSound: function(e) {
            this.sound = parseInt(e.target.options[e.target.selectedIndex].value);
            setCookie("sound", this.sound);
        },
        clickGameSeek: function(e) {
            this.getRidOfTooltip(e.currentTarget);
            if (this.mode == "human")
                return; //no newgame while playing
            if (this.seek)
            {
                this.conn.send(JSON.stringify({code:"cancelnewgame"}));
                delete localStorage["newgame"]; //cancel game seek
                this.seek = false;
            }
            else
                this.newGame("human");
        },
        clickComputerGame: function(e) {
            this.getRidOfTooltip(e.currentTarget);
            if (this.mode == "human")
                return; //no newgame while playing
            this.newGame("computer");
        },
        clickFriendGame: function(e) {
            this.getRidOfTooltip(e.currentTarget);
            document.getElementById("modal-fenedit").checked = true;
        },
        resign: function(e) {
            this.getRidOfTooltip(e.currentTarget);
            if (this.mode == "human" && this.oppConnected)
            {
                try {
                    this.conn.send(JSON.stringify({code: "resign", oppid: this.oppid}));
                } catch (INVALID_STATE_ERR) {
                    return; //socket is not ready (and not yet reconnected)
                }
            }
            this.endGame(this.mycolor=="w"?"0-1":"1-0");
        },
        newGame: function(mode, fenInit, color, oppId, moves, continuation) {
            const fen = fenInit || VariantRules.GenRandInitFen();
            console.log(fen); //DEBUG
            if (mode=="human" && !oppId)
            {
                const storageVariant = localStorage.getItem("variant");
                if (!!storageVariant && storageVariant !== variant)
                    return alert("Finish your " + storageVariant + " game first!");
                // Send game request and wait..
                localStorage["newgame"] = variant;
                this.seek = true;
                this.clearStorage(); //in case of
                try {
                    this.conn.send(JSON.stringify({code:"newgame", fen:fen}));
                } catch (INVALID_STATE_ERR) {
                    return; //nothing achieved
                }
                if (continuation !== "reconnect") //TODO: bad HACK...
                {
                    let modalBox = document.getElementById("modal-newgame");
                    modalBox.checked = true;
                    setTimeout(() => { modalBox.checked = false; }, 2000);
                }
                return;
            }
            this.vr = new VariantRules(fen, moves || []);
            this.score = "*";
            this.pgnTxt = ""; //redundant with this.score = "*", but cleaner
            this.mode = mode;
            this.incheck = []; //in case of
            this.fenStart = (continuation ? localStorage.getItem("fenStart") : fen);
            if (mode=="human")
            {
                // Opponent found!
                if (!continuation) //not playing sound on game continuation
                {
                    if (this.sound >= 1)
                        new Audio("/sounds/newgame.mp3").play().then(() => {}).catch(err => {});
                    document.getElementById("modal-newgame").checked = false;
                }
                this.oppid = oppId;
                this.oppConnected = !continuation;
                this.mycolor = color;
                this.seek = false;
                if (!!moves && moves.length > 0) //imply continuation
                {
                    const lastMove = moves[moves.length-1];
                    this.vr.undo(lastMove);
                    this.incheck = this.vr.getCheckSquares(lastMove);
                    this.vr.play(lastMove, "ingame");
                }
                delete localStorage["newgame"];
                this.setStorage(); //in case of interruptions
            }
            else if (mode == "computer")
            {
                this.mycolor = Math.random() < 0.5 ? 'w' : 'b';
                if (this.mycolor == 'b')
                    setTimeout(this.playComputerMove, 500);
            }
            //else: against a (IRL) friend: nothing more to do
        },
        playComputerMove: function() {
            const timeStart = Date.now();
            const compMove = this.vr.getComputerMove();
            // (first move) HACK: avoid selecting elements before they appear on page:
            const delay = Math.max(500-(Date.now()-timeStart), 0);
            setTimeout(() => {
                if (this.mode == "computer") //Warning: mode could have changed!
                    this.play(compMove, "animate")
            }, delay);
        },
        // Get the identifier of a HTML table cell from its numeric coordinates o.x,o.y.
        getSquareId: function(o) {
            // NOTE: a separator is required to allow any size of board
            return  "sq-" + o.x + "-" + o.y;
        },
        // Inverse function
        getSquareFromId: function(id) {
            let idParts = id.split('-');
            return [parseInt(idParts[1]), parseInt(idParts[2])];
        },
        mousedown: function(e) {
            e = e || window.event;
            let ingame = false;
            let elem = e.target;
            while (!ingame && elem !== null)
            {
                if (elem.classList.contains("game"))
                {
                    ingame = true;
                    break;
                }
                elem = elem.parentElement;
            }
            if (!ingame) //let default behavior (click on button...)
                return;
            e.preventDefault(); //disable native drag & drop
            if (!this.selectedPiece && e.target.classList.contains("piece"))
            {
                // Next few lines to center the piece on mouse cursor
                let rect = e.target.parentNode.getBoundingClientRect();
                this.start = {
                    x: rect.x + rect.width/2,
                    y: rect.y + rect.width/2,
                    id: e.target.parentNode.id
                };
                this.selectedPiece = e.target.cloneNode();
                this.selectedPiece.style.position = "absolute";
                this.selectedPiece.style.top = 0;
                this.selectedPiece.style.display = "inline-block";
                this.selectedPiece.style.zIndex = 3000;
                let startSquare = this.getSquareFromId(e.target.parentNode.id);
                const iCanPlay = this.mode!="idle"
                    && (this.mode=="friend" || this.vr.canIplay(this.mycolor,startSquare));
                this.possibleMoves = iCanPlay ? this.vr.getPossibleMovesFrom(startSquare) : [];
                // Next line add moving piece just after current image
                // (required for Crazyhouse reserve)
                e.target.parentNode.insertBefore(this.selectedPiece, e.target.nextSibling);
            }
        },
        mousemove: function(e) {
            if (!this.selectedPiece)
                return;
            e = e || window.event;
            // If there is an active element, move it around
            if (!!this.selectedPiece)
            {
                const [offsetX,offsetY] = !!e.clientX
                    ? [e.clientX,e.clientY] //desktop browser
                    : [e.changedTouches[0].pageX, e.changedTouches[0].pageY]; //smartphone
                this.selectedPiece.style.left = (offsetX-this.start.x) + "px";
                this.selectedPiece.style.top = (offsetY-this.start.y) + "px";
            }
        },
        mouseup: function(e) {
            if (!this.selectedPiece)
                return;
            e = e || window.event;
            // Read drop target (or parentElement, parentNode... if type == "img")
            this.selectedPiece.style.zIndex = -3000; //HACK to find square from final coords
            const [offsetX,offsetY] = !!e.clientX
                ? [e.clientX,e.clientY]
                : [e.changedTouches[0].pageX, e.changedTouches[0].pageY];
            let landing = document.elementFromPoint(offsetX, offsetY);
            this.selectedPiece.style.zIndex = 3000;
            // Next condition: classList.contains(piece) fails because of marks
            while (landing.tagName == "IMG")
                landing = landing.parentNode;
            if (this.start.id == landing.id)
            {
                // A click: selectedPiece and possibleMoves are already filled
                return;
            }
            // OK: process move attempt
            let endSquare = this.getSquareFromId(landing.id);
            let moves = this.findMatchingMoves(endSquare);
            this.possibleMoves = [];
            if (moves.length > 1)
                this.choices = moves;
            else if (moves.length==1)
                this.play(moves[0]);
            // Else: impossible move
            this.selectedPiece.parentNode.removeChild(this.selectedPiece);
            delete this.selectedPiece;
            this.selectedPiece = null;
        },
        findMatchingMoves: function(endSquare) {
            // Run through moves list and return the matching set (if promotions...)
            let moves = [];
            this.possibleMoves.forEach(function(m) {
                if (endSquare[0] == m.end.x && endSquare[1] == m.end.y)
                    moves.push(m);
            });
            return moves;
        },
        animateMove: function(move) {
            let startSquare = document.getElementById(this.getSquareId(move.start));
            let endSquare = document.getElementById(this.getSquareId(move.end));
            let rectStart = startSquare.getBoundingClientRect();
            let rectEnd = endSquare.getBoundingClientRect();
            let translation = {x:rectEnd.x-rectStart.x, y:rectEnd.y-rectStart.y};
            let movingPiece =
                document.querySelector("#" + this.getSquareId(move.start) + " > img.piece");
            // HACK for animation (with positive translate, image slides "under background")
            // Possible improvement: just alter squares on the piece's way...
            squares = document.getElementsByClassName("board");
            for (let i=0; i<squares.length; i++)
            {
                let square = squares.item(i);
                if (square.id != this.getSquareId(move.start))
                    square.style.zIndex = "-1";
            }
            movingPiece.style.transform = "translate(" + translation.x + "px," +
                translation.y + "px)";
            movingPiece.style.transitionDuration = "0.2s";
            movingPiece.style.zIndex = "3000";
            setTimeout( () => {
                for (let i=0; i<squares.length; i++)
                    squares.item(i).style.zIndex = "auto";
                movingPiece.style = {}; //required e.g. for 0-0 with KR swap
                this.play(move);
            }, 200);
        },
        play: function(move, programmatic) {
            if (!move)
            {
                // Navigate after game is over
                if (this.cursor >= this.vr.moves.length)
                    return; //already at the end
                move = this.vr.moves[this.cursor++];
            }
            if (!!programmatic) //computer or human opponent
            {
                this.animateMove(move);
                return;
            }
            // Not programmatic, or animation is over
            if (this.mode == "human" && this.vr.turn == this.mycolor)
                this.conn.send(JSON.stringify({code:"newmove", move:move, oppid:this.oppid}));
            if (this.sound == 2)
                new Audio("/sounds/chessmove1.mp3").play().then(() => {}).catch(err => {});
            if (this.mode != "idle")
            {
                this.incheck = this.vr.getCheckSquares(move); //is opponent in check?
                this.vr.play(move, "ingame");
            }
            else
            {
                VariantRules.PlayOnBoard(this.vr.board, move);
                this.$forceUpdate(); //TODO: ?!
            }
            if (this.mode == "human")
                this.updateStorage(); //after our moves and opponent moves
            if (this.mode != "idle")
            {
                const eog = this.vr.checkGameOver();
                if (eog != "*")
                    this.endGame(eog);
            }
            if (this.mode == "computer" && this.vr.turn != this.mycolor)
                setTimeout(this.playComputerMove, 500);
        },
        undo: function() {
            // Navigate after game is over
            if (this.cursor == 0)
                return; //already at the beginning
            if (this.cursor == this.vr.moves.length)
                this.incheck = []; //in case of...
            const move = this.vr.moves[--this.cursor];
            VariantRules.UndoOnBoard(this.vr.board, move);
            this.$forceUpdate(); //TODO: ?!
        },
        undoInGame: function() {
            const lm = this.vr.lastMove;
            if (!!lm)
                this.vr.undo(lm);
        },
    },
})