Client/assets/js/server-selector.js

var remote = require("remote");
var remotefs = remote.require("fs-extra");
var dns = remote.require("dns");
var path = remote.require("path");
var dialog = remote.require("dialog");
var net = remote.require("net");
var spawn = require("child_process").spawn;

var userData = remote.require("app").getPath("userData");
var configPath = path.join(userData, "config.json");
var serversPath = path.join(userData, "servers.json");
var versionsPath = path.join(userData, "versions.json");
var cacheRoot = path.join(userData, "/../../LocalLow/Unity/Web Player/Cache");
var offlineRootDefault = path.join(cacheRoot, "../OfflineCache");
var offlineRoot = offlineRootDefault;

var cdnString = "http://cdn.dexlabs.systems/ff/big";

var versionArray;
var serverArray;
var cacheSizes;
var defaultHashes;
var config;

function enableServerListButtons() {
    $("#of-connect-button").removeClass("disabled");
    $("#of-connect-button").prop("disabled", false);
    $("#of-editserver-button").removeClass("disabled");
    $("#of-editserver-button").prop("disabled", false);
    $("#of-deleteserver-button").removeClass("disabled");
    $("#of-deleteserver-button").prop("disabled", false);
}

function disableServerListButtons() {
    $("#of-connect-button").addClass("disabled");
    $("#of-connect-button").prop("disabled", true);
    $("#of-editserver-button").addClass("disabled");
    $("#of-editserver-button").prop("disabled", true);
    $("#of-deleteserver-button").addClass("disabled");
    $("#of-deleteserver-button").prop("disabled", true);
}

function enableVersionAddButton() {
    $("#of-addversion-button").removeClass("disabled");
    $("#of-addversion-button").prop("disabled", false);
}

function enableVersionListButtons() {
    $("#of-editversion-button").removeClass("disabled");
    $("#of-editversion-button").prop("disabled", false);
    $("#of-deleteversion-button").removeClass("disabled");
    $("#of-deleteversion-button").prop("disabled", false);
}

function disableVersionAddButton() {
    $("#of-addversion-button").addClass("disabled");
    $("#of-addversion-button").prop("disabled", true);
}

function disableVersionListButtons() {
    $("#of-editversion-button").addClass("disabled");
    $("#of-editversion-button").prop("disabled", true);
    $("#of-deleteversion-button").addClass("disabled");
    $("#of-deleteversion-button").prop("disabled", true);
}

function getAppVersion() {
    appVersion = remote.require("app").getVersion();

    // Simplify version, ex. 1.4.0 -> 1.4,
    // but only if a revision number isn't present
    if (appVersion.endsWith(".0")) {
        return appVersion.substr(0, appVersion.length - 2);
    } else {
        return appVersion;
    }
}

function setAppVersionText() {
    $("#of-aboutversionnumber").text("Version " + getAppVersion());
}

function checkForNewAppVersion() {
    $("#of-about-button").removeClass("pulsing");
    setAppVersionText();
    if (config["autoupdate-check"] === true) {
        $.getJSON(
            "https://api.github.com/repos/OpenFusionProject/OpenFusionClient/releases/latest",
            {},
            function (data) {
                $.each(data, function (index, element) {
                    if (index === "tag_name" && element > getAppVersion()) {
                        console.log("New version available: " + element);
                        var downloadPage =
                            "https://github.com/OpenFusionProject/OpenFusionClient/releases/latest";
                        $("#of-aboutversionnumber").html(
                            "Version " +
                                getAppVersion() +
                                `<br>A new version is available! ` +
                                `Click <a href="#" onclick='remote.require("shell").openExternal("` +
                                downloadPage +
                                `");'>here</a> to download.`
                        );
                        $("#of-about-button").addClass("pulsing");
                        return false; // break out of loop early
                    }
                });
            }
        );
    }
}

function validateServerSave(modalName) {
    // works everytime a key is entered into the server save form
    var descInput = document.getElementById(modalName + "server-descinput");
    var ipInput = document.getElementById(modalName + "server-ipinput");
    var button = document.getElementById(modalName + "server-savebutton");
    var valid = true;

    descInput.classList.remove("invalidinput");
    ipInput.classList.remove("invalidinput");

    if (
        descInput.value.length <
            parseInt(descInput.getAttribute("minlength")) ||
        descInput.value.length > parseInt(descInput.getAttribute("maxlength"))
    ) {
        descInput.classList.add("invalidinput");
        valid = false;
    }

    if (!new RegExp(ipInput.getAttribute("pattern")).test(ipInput.value)) {
        ipInput.classList.add("invalidinput");
        valid = false;
    }

    if (valid) {
        button.removeAttribute("disabled");
    } else {
        button.setAttribute("disabled", "");
    }
}

function addServer() {
    var jsonToModify = JSON.parse(remotefs.readFileSync(serversPath));

    var server = {};
    server["uuid"] = uuidv4();
    server["description"] =
        $("#addserver-descinput").val().length == 0
            ? "My OpenFusion Server"
            : $("#addserver-descinput").val();
    server["ip"] =
        $("#addserver-ipinput").val().length == 0
            ? "127.0.0.1:23000"
            : $("#addserver-ipinput").val();
    server["version"] = $("#addserver-versionselect option:selected").text();
    //server['endpoint'] =

    jsonToModify["servers"].push(server);

    remotefs.writeFileSync(serversPath, JSON.stringify(jsonToModify, null, 4));
    loadServerList();
}

function editServer() {
    var jsonToModify = JSON.parse(remotefs.readFileSync(serversPath));
    $.each(jsonToModify["servers"], function (key, value) {
        if (value["uuid"] == getSelectedServer()) {
            value["description"] =
                $("#editserver-descinput").val().length == 0
                    ? value["description"]
                    : $("#editserver-descinput").val();
            value["ip"] =
                $("#editserver-ipinput").val().length == 0
                    ? value["ip"]
                    : $("#editserver-ipinput").val();
            value["version"] = $(
                "#editserver-versionselect option:selected"
            ).text();
        }
    });

    remotefs.writeFileSync(serversPath, JSON.stringify(jsonToModify, null, 4));
    loadServerList();
}

function deleteServer() {
    var jsonToModify = JSON.parse(remotefs.readFileSync(serversPath));
    var result = jsonToModify["servers"].filter(function (obj) {
        return obj.uuid === getSelectedServer();
    })[0];

    var resultindex = jsonToModify["servers"].indexOf(result);

    jsonToModify["servers"].splice(resultindex, 1);

    remotefs.writeFileSync(serversPath, JSON.stringify(jsonToModify, null, 4));
    loadServerList();
}

function restoreDefaultServers() {
    remotefs.copySync(
        path.join(__dirname, "/defaults/servers.json"),
        serversPath
    );
    loadServerList();
}

function validateVersionSave(modalName) {
    // works everytime a key is entered into the version save form
    var nameInput = document.getElementById(modalName + "version-nameinput");
    var urlInput = document.getElementById(modalName + "version-urlinput");
    var button = document.getElementById(modalName + "version-savebutton");
    var valid = true;

    nameInput.classList.remove("invalidinput");
    urlInput.classList.remove("invalidinput");

    var matchingVersions = versionArray.filter(function (obj) {
        return obj.name === nameInput.value;
    });
    var allowedMatches = modalName === "edit" ? 1 : 0;

    if (
        matchingVersions.length > allowedMatches ||
        !new RegExp(nameInput.getAttribute("pattern")).test(nameInput.value)
    ) {
        nameInput.classList.add("invalidinput");
        valid = false;
    }

    if (!new RegExp(urlInput.getAttribute("pattern")).test(urlInput.value)) {
        urlInput.classList.add("invalidinput");
        valid = false;
    }

    if (valid) {
        button.removeAttribute("disabled");
    } else {
        button.setAttribute("disabled", "");
    }
}

function addVersion() {
    var jsonToModify = JSON.parse(remotefs.readFileSync(versionsPath));

    var version = {};
    version["name"] =
        $("#addversion-nameinput").val().length == 0
            ? "custom-build-" + uuidv4().substring(0, 8)
            : $("#addversion-nameinput").val();
    version["url"] =
        $("#addversion-urlinput").val().length == 0
            ? cdnString + "/" + version["name"] + "/"
            : $("#addversion-urlinput").val();

    var matchingVersions = jsonToModify["versions"].filter(function (obj) {
        return obj.name === version["name"];
    });

    if (matchingVersions.length > 0) return;

    jsonToModify["versions"].unshift(version);

    remotefs.writeFileSync(versionsPath, JSON.stringify(jsonToModify, null, 4));
    loadCacheList();
    handleCache("hash-check", version["name"]);
}

function editVersion() {
    var jsonToModify = JSON.parse(remotefs.readFileSync(versionsPath));
    var editedVersionString = null;

    $.each(jsonToModify["versions"], function (key, value) {
        if (
            value["name"] == getSelectedVersion() &&
            !defaultHashes.hasOwnProperty(value["name"])
        ) {
            value["name"] =
                $("#editversion-nameinput").val().length == 0
                    ? value["name"]
                    : $("#editversion-nameinput").val();
            value["url"] =
                $("#editversion-urlinput").val().length == 0
                    ? value["url"]
                    : $("#editversion-urlinput").val();
            editedVersionString = value["name"];
        }
    });

    if (!editedVersionString) return;

    remotefs.writeFileSync(versionsPath, JSON.stringify(jsonToModify, null, 4));
    loadCacheList();
    handleCache("hash-check", editedVersionString);
}

function deleteVersion() {
    var jsonToModify = JSON.parse(remotefs.readFileSync(versionsPath));

    var result = jsonToModify["versions"].filter(function (obj) {
        return obj.name === getSelectedVersion();
    })[0];

    if (defaultHashes.hasOwnProperty(result.name)) return;

    var resultindex = jsonToModify["versions"].indexOf(result);

    jsonToModify["versions"].splice(resultindex, 1);

    remotefs.writeFileSync(versionsPath, JSON.stringify(jsonToModify, null, 4));
    loadCacheList();
    delete cacheSizes[result.name];
}

function restoreDefaultVersions() {
    remotefs.copySync(
        path.join(__dirname, "/defaults/versions.json"),
        versionsPath
    );
    loadCacheList();
    handleCache("hash-check");
}

function editConfig() {
    var jsonToModify = JSON.parse(remotefs.readFileSync(configPath));

    jsonToModify["autoupdate-check"] = $("#editconfig-autoupdate").prop(
        "checked"
    );
    jsonToModify["cache-swapping"] = $("#editconfig-cacheswapping").prop(
        "checked"
    );
    jsonToModify["enable-offline-cache"] = $(
        "#editconfig-enableofflinecache"
    ).prop("checked");
    jsonToModify["verify-offline-cache"] = $(
        "#editconfig-verifyofflinecache"
    ).prop("checked");

    var dirInput = $("#editconfig-offlinecachelocation:text").val();
    var shouldChangeRoot =
        remotefs.existsSync(dirInput) &&
        remotefs.statSync(dirInput).isDirectory();

    jsonToModify["offline-cache-location"] = shouldChangeRoot
        ? dirInput
        : offlineRoot;

    remotefs.writeFileSync(configPath, JSON.stringify(jsonToModify, null, 4));

    loadConfig();
    // check all offline caches if the offline root changes
    if (shouldChangeRoot) handleCache("hash-check", null, "offline");
}

function validateCacheLocation() {
    var input = document.getElementById("editconfig-offlinecachelocation");
    var button = document.getElementById("editconfig-savebutton");
    var parent = path.join(input.value, "/..");

    input.classList.remove("invalidinput");
    button.removeAttribute("disabled");

    // Parent MUST exist and be a directory
    // If the target exists, check that is also a directory
    // Also, prevent putting the offline cache inside of
    // the normal cache folder to prevent shenanigans
    if (
        !remotefs.existsSync(parent) ||
        !remotefs.statSync(parent).isDirectory() ||
        (remotefs.existsSync(input.value) &&
            !remotefs.statSync(input.value).isDirectory()) ||
        path.join(input.value, ".") === path.join(cacheRoot, "/..") ||
        path.join(input.value, ".").startsWith(path.join(cacheRoot))
    ) {
        input.classList.add("invalidinput");
        button.setAttribute("disabled", "");
    }
}

function loadGameVersions() {
    var versionJson = remotefs.readJsonSync(versionsPath);
    versionArray = versionJson["versions"];

    $("#addserver-versionselect").empty();
    $("#editserver-versionselect").empty();

    $.each(versionArray, function (key, value) {
        $(new Option(value.name, "val")).appendTo("#addserver-versionselect");
        $(new Option(value.name, "val")).appendTo("#editserver-versionselect");
    });
}

function loadConfig() {
    // Load config object globally
    config = remotefs.readJsonSync(configPath);

    $("#editconfig-autoupdate").prop("checked", config["autoupdate-check"]);
    $("#editconfig-cacheswapping").prop("checked", config["cache-swapping"]);
    $("#editconfig-enableofflinecache").prop(
        "checked",
        config["enable-offline-cache"]
    );
    $("#editconfig-verifyofflinecache").prop(
        "checked",
        config["verify-offline-cache"]
    );

    // alter offline root globally
    offlineRoot = config["offline-cache-location"] || offlineRootDefault;
    $("#editconfig-offlinecachelocation:text").val(offlineRoot);

    checkForNewAppVersion();
    validateCacheLocation();
}

function loadServerList() {
    var serverJson = remotefs.readJsonSync(serversPath);
    serverArray = serverJson["servers"];

    deselectServer(); // Remove selection and disable buttons until another server is selected
    $(".server-listing-entry").remove(); // Clear out old stuff, if any

    if (serverArray.length > 0) {
        // Servers were found in the JSON
        $("#server-listing-placeholder").attr("hidden", true);
        $.each(serverArray, function (key, value) {
            // Create the row, and populate the cells
            var row = document.createElement("tr");
            row.className = "server-listing-entry";
            row.setAttribute("id", value.uuid);
            var cellName = document.createElement("td");
            cellName.textContent = value.description;
            var cellVersion = document.createElement("td");
            cellVersion.textContent = value.version;
            cellVersion.className = "text-monospace";

            row.appendChild(cellName);
            row.appendChild(cellVersion);
            $("#server-tablebody").append(row);
        });
    } else {
        // No servers are added, make sure placeholder is visible
        $("#server-listing-placeholder").attr("hidden", false);
    }
}

function loadCacheList() {
    // we might want to use a new version right away, so reload them
    loadGameVersions();

    // load default hashes.json for reference while running the cache handler
    if (!defaultHashes) {
        defaultHashes = remotefs.readJsonSync(
            path.join(__dirname, "/defaults/hashes.json")
        );
    }

    deselectVersion(); // Remove selection and disable buttons until another server is selected
    $(".cache-listing-entry").remove(); // Clear out old stuff, if any

    $.each(versionArray, function (key, value) {
        var row = document.createElement("tr");
        row.className = "cache-listing-entry";
        row.setAttribute("id", value.name);

        var cellVersion = document.createElement("td");
        cellVersion.textContent = value.name;
        cellVersion.className = "text-monospace";

        var cellPlayableCache = getCacheInfoCell(value.name, "playable");
        var cellOfflineCache = getCacheInfoCell(value.name, "offline");

        row.appendChild(cellVersion);
        row.appendChild(cellPlayableCache);
        row.appendChild(cellOfflineCache);

        $("#cache-tablebody").append(row);
    });

    // simulate a cache handler run so that the buttons update properly
    storageLoadingStart();
    storageLoadingUpdate(cacheSizes);
    storageLoadingComplete(cacheSizes);
}

function getCacheElemID(versionString, cacheMode, elementName) {
    return [versionString, cacheMode, "cache", elementName]
        .filter(function (value) {
            return typeof value !== "undefined";
        })
        .join("-");
}

function getCacheButtonID(versionString, cacheMode, buttonMode) {
    return [
        getCacheElemID(versionString, cacheMode),
        buttonMode,
        "button",
    ].join("-");
}

function getCacheLabelText(sizes) {
    if (!sizes || sizes.total === 0) return "?.?? GB / ?.?? GB";

    var gb = 1 << 30;
    var labelText =
        (sizes.intact / gb).toFixed(2) +
        " / " +
        (sizes.total / gb).toFixed(2) +
        " GB";

    if (sizes.altered > 0) {
        labelText +=
            "<br/>(" + (sizes.altered / gb).toFixed(2) + " GB Altered)";
    }

    return labelText;
}

function getCacheInfoCell(versionString, cacheMode) {
    var divID = getCacheElemID(versionString, cacheMode, "div");
    var labelID = getCacheElemID(versionString, cacheMode, "label");

    var settings = {
        download: {
            icon: "fas fa-download",
            class: "btn btn-success mr-1",
            tooltip: "Download Cache",
        },
        fix: {
            icon: "fas fa-hammer",
            class: "btn btn-warning mr-1",
            tooltip: "Fix Altered Files in Cache",
        },
        delete: {
            icon: "fas fa-trash-alt",
            class: "btn btn-danger mr-1",
            tooltip: "Delete Cache",
        },
    };

    var cellCache = document.createElement("td");
    var divCacheAll = document.createElement("div");

    var labelCache = document.createElement("label");
    labelCache.setAttribute("id", labelID);
    labelCache.setAttribute("for", divID);
    // pull existing info from cacheSizes when available
    labelCache.innerHTML = getCacheLabelText(
        cacheSizes && cacheSizes[versionString]
            ? cacheSizes[versionString][cacheMode]
            : null
    );

    var divCacheButtons = document.createElement("div");
    divCacheButtons.setAttribute("id", labelID);

    $.each(settings, function (buttonMode, config) {
        // only delete allowed for playable game caches
        if (cacheMode === "playable" && buttonMode !== "delete") {
            return;
        }

        var buttonID = getCacheButtonID(versionString, cacheMode, buttonMode);

        var iconItalic = document.createElement("i");
        iconItalic.setAttribute("class", config.icon);

        var buttonCache = document.createElement("button");
        buttonCache.setAttribute("id", buttonID);
        buttonCache.setAttribute("class", config.class);
        buttonCache.setAttribute("title", config.tooltip);
        buttonCache.setAttribute("type", "button");
        // handler setup
        buttonCache.setAttribute(
            "onclick",
            'handleCache("' +
                buttonMode +
                '", "' +
                versionString +
                '", "' +
                cacheMode +
                '");'
        );
        buttonCache.appendChild(iconItalic);

        divCacheButtons.appendChild(buttonCache);
    });

    divCacheAll.appendChild(labelCache);
    divCacheAll.appendChild(divCacheButtons);
    cellCache.appendChild(divCacheAll);

    return cellCache;
}

function storageLoadingStart(vString, cMode) {
    // determine which cache versions and modes to visually update
    var versionStrings = [];
    $.each(versionArray, function (key, value) {
        if (vString) {
            if (vString === value.name) versionStrings.push(value.name);
        } else {
            versionStrings.push(value.name);
        }
    });
    var cacheModes = cMode ? [cMode] : ["offline", "playable"];

    // deselect and disable the add version button until they are re-enabled
    deselectVersion();
    disableVersionAddButton();

    // turn buttons into spinners
    $.each(versionStrings, function (vKey, versionString) {
        $.each(cacheModes, function (cKey, cacheMode) {
            var buttonDelete = document.getElementById(
                getCacheButtonID(versionString, cacheMode, "delete")
            );
            var buttonDownload = document.getElementById(
                getCacheButtonID(versionString, cacheMode, "download")
            );
            var buttonFix = document.getElementById(
                getCacheButtonID(versionString, cacheMode, "fix")
            );

            if (!buttonDelete) return;

            buttonDelete.setAttribute("disabled", "");
            buttonDelete.children[0].setAttribute(
                "class",
                "fas fa-spinner fa-spin fa-fw"
            );

            if (cacheMode === "offline") {
                buttonDownload.setAttribute("disabled", "");
                buttonDownload.children[0].setAttribute(
                    "class",
                    "fas fa-spinner fa-spin fa-fw"
                );

                buttonFix.setAttribute("disabled", "");
                buttonFix.children[0].setAttribute(
                    "class",
                    "fas fa-spinner fa-spin fa-fw"
                );
            }
        });
    });
}

function storageLoadingUpdate(allSizes) {
    // update cacheSizes and display results
    $.each(allSizes, function (versionString, vSizes) {
        $.each(vSizes, function (cacheMode, sizes) {
            var label = document.getElementById(
                getCacheElemID(versionString, cacheMode, "label")
            );

            cacheSizes = cacheSizes || {};
            cacheSizes[versionString] = cacheSizes[versionString] || {};
            cacheSizes[versionString][cacheMode] = sizes || {};

            if (!label) return;

            label.innerHTML = getCacheLabelText(sizes);
        });
    });
}

function storageLoadingComplete(allSizes) {
    // re-enable buttons according to the sizes that were read
    $.each(allSizes, function (versionString, vSizes) {
        $.each(vSizes, function (cacheMode, sizes) {
            var buttonDelete = document.getElementById(
                getCacheButtonID(versionString, cacheMode, "delete")
            );
            var buttonDownload = document.getElementById(
                getCacheButtonID(versionString, cacheMode, "download")
            );
            var buttonFix = document.getElementById(
                getCacheButtonID(versionString, cacheMode, "fix")
            );

            if (!buttonDelete) return;

            buttonDelete.children[0].setAttribute("class", "fas fa-trash-alt");

            if (cacheMode === "offline") {
                buttonDownload.children[0].setAttribute(
                    "class",
                    "fas fa-download"
                );
                buttonFix.children[0].setAttribute("class", "fas fa-hammer");
            }

            if (sizes.intact > 0 || sizes.altered > 0) {
                buttonDelete.removeAttribute("disabled");

                if (cacheMode === "offline") {
                    buttonDownload.setAttribute("disabled", "");

                    if (sizes.altered > 0 || sizes.intact < sizes.total) {
                        buttonFix.removeAttribute("disabled");
                    }
                }
            } else {
                buttonDelete.setAttribute("disabled", "");

                if (cacheMode === "offline") {
                    buttonDownload.removeAttribute("disabled");
                    buttonFix.setAttribute("disabled", "");
                }
            }
        });
    });

    // finally, re-enable the version add button
    enableVersionAddButton();
}

function handleCache(operation, versionString, cacheMode, callback) {
    // see if any versions match (could be undefined or null)
    var versions = versionArray.filter(function (obj) {
        return obj.name === versionString;
    });
    // pull version url from the found object, if none found, use the default cdn link
    var cdnRoot = versions.length === 0 ? cdnString : versions[0].url;

    var lastSizes = { intact: 0, altered: 0, total: 0 };
    var buf = "";

    // start loading on the given version and mode (could be undefined or null, which means 'all')
    storageLoadingStart(versionString, cacheMode);

    // create the server and socket listener
    var server = net.createServer(function (sock) {
        sock.setEncoding("utf8");

        sock.on("data", function (data) {
            // read data until the next \n, and keep reading
            // sometimes the updates are buffered, so there might be multiple objects
            // per update, and partial objects as well
            // buffer parsing allows us to handle these cases
            buf += data;

            var end = buf.indexOf("\n");

            while (end > 0) {
                var sub = buf.substring(0, end);
                buf = buf.substring(end + 1);

                // run a storage update here
                lastSizes = JSON.parse(sub);
                storageLoadingUpdate(lastSizes);

                end = buf.indexOf("\n");
            }
        });
    });

    // start listening on a randomly acquired port, and spawn cache handler when ready
    server.listen(0, "localhost", function () {
        spawn(
            path.join(__dirname, "lib", "cache_handler.exe"),
            [
                "--operation",
                operation,
                // roots below contain version-agnostic main directories for caches
                "--playable-root",
                cacheRoot,
                "--offline-root",
                offlineRoot,
                "--user-dir",
                userData,
                // CDN root contains version-specific directory, unless cacheMode is "all"
                "--cdn-root",
                cdnRoot,
                "--cache-mode",
                cacheMode || "all",
                "--cache-version",
                versionString || "all",
                // learn port from the server object and tell the script where to connect
                "--port",
                server.address().port,
                // tell the script which versions and caches are official
                "--official-caches",
            ].concat(Object.keys(defaultHashes)),
            {
                stdio: "inherit",
            }
        ).on("exit", function (code, signal) {
            if (code !== 0 || signal) {
                dialog.showErrorBox(
                    "Sorry!",
                    'Process "' +
                        operation +
                        '" failed with code ' +
                        code +
                        " and signal " +
                        signal +
                        "."
                );
            }

            // when the script exits, close the server
            server.close();
            // set button state accordingly
            storageLoadingComplete(lastSizes);
            // then run the given callback (if any)
            if (callback) callback(lastSizes);
        });
    });
}

function performCacheSwap(newVersion) {
    var currentCache = path.join(cacheRoot, "FusionFall");
    var newCache = path.join(cacheRoot, newVersion);
    var record = path.join(userData, ".lastver");

    // If cache renaming would result in a no-op (ex. launching the same version
    // two times), then skip it. This avoids permissions errors with multiple clients
    // (file/folder is already open in another process)
    var skip = false;

    if (remotefs.existsSync(currentCache)) {
        // Cache already exists, find out what version it belongs to
        if (remotefs.existsSync(record)) {
            var lastVersion = remotefs.readFileSync(
                record,
                (encoding = "utf8")
            );
            if (lastVersion != newVersion) {
                // Remove the directory we're trying to store the
                // existing cache to if it already exists for whatever
                // reason, as it would cause an EPERM error otherwise.
                // This is a no-op if the directory doesn't exist
                remotefs.removeSync(path.join(cacheRoot, lastVersion));
                // Store old cache to named directory
                remotefs.renameSync(
                    currentCache,
                    path.join(cacheRoot, lastVersion)
                );
            } else {
                console.log("Cached version unchanged, skipping rename");
                skip = true;
            }
            console.log("Current cache is " + lastVersion);
        }
    }

    // Make note of what version we are launching for next launch
    remotefs.writeFileSync(record, newVersion);

    if (remotefs.existsSync(newCache) && !skip) {
        // Rename saved cache to FusionFall
        remotefs.renameSync(newCache, currentCache);
        console.log("Current cache swapped to " + newVersion);
    }
}

function prepGameInfo(serverUUID) {
    var serverInfo = serverArray.filter(function (obj) {
        return obj.uuid === serverUUID;
    })[0];
    var versionInfo = versionArray.filter(function (obj) {
        return obj.name === serverInfo.version;
    })[0];

    // If cache swapping property exists AND is `true`, run cache swapping logic
    if (config["cache-swapping"]) {
        try {
            performCacheSwap(versionInfo.name);
        } catch (ex) {
            console.log(
                "Error when swapping cache, it may get overwritten:\n" + ex
            );
        }
    }

    if (!config["enable-offline-cache"]) {
        // if we always ignore the offline cache, just use the URL
        setGameInfo(serverInfo, versionInfo.url);
        return;
    }

    var offlinePath = path.join(offlineRoot, versionInfo.name);
    var offlineURL = "file:///" + offlinePath.replace(/\\/g, "/") + "/";

    if (config["verify-offline-cache"]) {
        // if required, do a full hash check, and use the offline cache only if it is fully intact
        handleCache(
            "hash-check",
            versionInfo.name,
            "offline",
            function (sizes) {
                var versionURL =
                    sizes.intact < sizes.total ? versionInfo.url : offlineURL;
                setGameInfo(serverInfo, versionURL);
            }
        );
        return;
    }

    // otherwise, if main.unity3d is present, use the offline cache
    var mainPath = path.join(offlinePath, "main.unity3d");
    var versionURL = !remotefs.existsSync(mainPath)
        ? versionInfo.url
        : offlineURL;
    setGameInfo(serverInfo, versionURL);
}

// For writing loginInfo.php, assetInfo.php, etc.
function setGameInfo(serverInfo, versionURL) {
    // slash fix if people mess it up via text editors
    var versionURLRoot = versionURL.endsWith("/")
        ? versionURL
        : versionURL + "/";
    window.assetUrl = versionURLRoot; // game-client.js needs to access this
    console.log("Cache will expand from " + versionURLRoot);

    remotefs.writeFileSync(path.join(__dirname, "assetInfo.php"), assetUrl);
    if (serverInfo.hasOwnProperty("endpoint")) {
        var httpEndpoint = serverInfo.endpoint.replace("https://", "http://");
        remotefs.writeFileSync(
            path.join(__dirname, "rankurl.txt"),
            httpEndpoint + "getranks"
        );
        // Write these out too
        remotefs.writeFileSync(
            path.join(__dirname, "sponsor.php"),
            httpEndpoint + "upsell/sponsor.png"
        );
        remotefs.writeFileSync(
            path.join(__dirname, "images.php"),
            httpEndpoint + "upsell/"
        );
    } else {
        // Remove/default the endpoint related stuff, this server won't be using it
        if (remotefs.existsSync(path.join(__dirname, "rankurl.txt"))) {
            remotefs.unlinkSync(path.join(__dirname, "rankurl.txt"));
            remotefs.writeFileSync(
                path.join(__dirname, "sponsor.php"),
                "assets/img/welcome.png"
            );
            remotefs.writeFileSync(
                path.join(__dirname, "images.php"),
                "assets/img/"
            );
        }
    }

    // Server address parsing
    var address;
    var port;
    var sepPos = serverInfo.ip.indexOf(":");
    if (sepPos > -1) {
        address = serverInfo.ip.substr(0, sepPos);
        port = serverInfo.ip.substr(sepPos + 1);
    } else {
        address = serverInfo.ip;
        port = 23000; // default
    }

    // DNS resolution. there is no synchronous version for some stupid reason
    if (!address.match(/^[0-9.]+$/)) {
        dns.lookup(address, (family = 4), function (err, resolvedAddress) {
            if (!err) {
                console.log("Resolved " + address + " to " + resolvedAddress);
                address = resolvedAddress;
            } else {
                console.log("Err: " + err.code);
            }
            prepConnection(address, port);
        });
    } else {
        console.log(address + " is an IP; skipping DNS lookup");
        prepConnection(address, port);
    }
}

function prepConnection(address, port) {
    var full = address + ":" + port;
    console.log("Will connect to " + full);
    remotefs.writeFileSync(path.join(__dirname, "loginInfo.php"), full);
    launchGame();
}

function browseOfflineCache() {
    var browsePath = dialog.showOpenDialog({ properties: ["openDirectory"] });
    var offlineCacheInput = document.getElementById(
        "editconfig-offlinecachelocation"
    );
    if (browsePath && offlineCacheInput) {
        offlineCacheInput.value = browsePath;
        validateCacheLocation();
    }
}

// Returns the UUID of the server with the selected background color.
// Yes, there are probably better ways to go about this, but it works well enough.
function getSelectedServer() {
    return $("#server-tablebody > tr.bg-primary").prop("id");
}

// Returns the name of the version with the selected background color.
function getSelectedVersion() {
    return $("#cache-tablebody > tr.bg-primary").prop("id");
}

function connectToServer() {
    // Get ID of the selected server, which corresponds to its UUID in the json
    console.log("Connecting to server with UUID of " + getSelectedServer());

    // Prevent the user from clicking anywhere else during the transition
    $("body,html").css("pointer-events", "none");
    stopEasterEggs();
    $("#of-serverselector").fadeOut("slow", function () {
        setTimeout(function () {
            $("body,html").css("pointer-events", "");
            prepGameInfo(getSelectedServer());
        }, 200);
    });
}

// If applicable, deselect currently selected server.
function deselectServer() {
    disableServerListButtons();
    $(".server-listing-entry").removeClass("bg-primary");
}

// If applicable, deselect currently selected version.
function deselectVersion() {
    disableVersionListButtons();
    $(".cache-listing-entry").removeClass("bg-primary");
}

// Select a server
$("#server-table").on("click", ".server-listing-entry", function (event) {
    enableServerListButtons();
    $(this).addClass("bg-primary").siblings().removeClass("bg-primary");
});

// Select a version (if allowed)
$("#cache-table").on("click", ".cache-listing-entry", function (event) {
    // wait for the add button to be re-enabled first
    if ($("#of-addversion-button").prop("disabled")) return;
    // do not select default builds
    if (defaultHashes.hasOwnProperty($(this).attr("id"))) return;

    enableVersionListButtons();
    $(this).addClass("bg-primary").siblings().removeClass("bg-primary");
});

// QoL feature: if you double click on a server it will connect
$("#server-table").on("dblclick", ".server-listing-entry", function (event) {
    $(this).addClass("bg-primary").siblings().removeClass("bg-primary");
    connectToServer();
});

$("#of-addservermodal").on("show.bs.modal", function (e) {
    validateServerSave("add");
});

$("#of-addversionmodal").on("show.bs.modal", function (e) {
    validateVersionSave("add");
});

$("#of-editservermodal").on("show.bs.modal", function (e) {
    // populate the edit modal with existing values
    var jsonToModify = remotefs.readJsonSync(serversPath);

    $.each(jsonToModify["servers"], function (key, value) {
        if (value["uuid"] == getSelectedServer()) {
            $("#editserver-descinput")[0].value = value["description"];
            $("#editserver-ipinput")[0].value = value["ip"];

            var versionIndex = -1;
            $.each($("#editserver-versionselect")[0], function (key, val) {
                if (val.text === value["version"]) {
                    versionIndex = key;
                }
            });
            $("#editserver-versionselect")[0].selectedIndex = versionIndex;
        }
    });

    validateServerSave("edit");
});

$("#of-editversionmodal").on("show.bs.modal", function (e) {
    // populate the edit modal with existing values
    var jsonToModify = remotefs.readJsonSync(versionsPath);

    $.each(jsonToModify["versions"], function (key, value) {
        if (value["name"] == getSelectedVersion()) {
            $("#editversion-nameinput")[0].value = value["name"];
            $("#editversion-urlinput")[0].value = value["url"];
        }
    });

    validateVersionSave("edit");
});

// Replace server name to delete
$("#of-deleteservermodal").on("show.bs.modal", function (e) {
    var result = serverArray.filter(function (obj) {
        return obj.uuid === getSelectedServer();
    })[0];
    $("#deleteserver-servername").html(result.description);
});

// Replace version name to delete
$("#of-deleteversionmodal").on("show.bs.modal", function (e) {
    var result = versionArray.filter(function (obj) {
        return obj.name === getSelectedVersion();
    })[0];
    $("#deleteversion-versionname").html(result.name);
});

// Run the global hash check once and only if the cache modal is ever shown
$("#of-editcacheconfigmodal").on("show.bs.modal", function (e) {
    if (!cacheSizes) handleCache("hash-check");
});

// Keep all config values synced on modal show
// Avoids cases where people forget that they changed the offline root but did not save
$("#of-editconfigmodal").on("show.bs.modal", function (e) {
    loadConfig();
});