session.ts

// Copyright (c) Microsoft Corporation.
// Licensed under the MIT License.

import fs = require("fs");
import net = require("net");
import path = require("path");
import * as semver from "semver";
import vscode = require("vscode");
import TelemetryReporter from "@vscode/extension-telemetry";
import { Message } from "vscode-jsonrpc";
import { Logger } from "./logging";
import { PowerShellProcess } from "./process";
import Settings = require("./settings");
import utils = require("./utils");

import {
    CloseAction, DocumentSelector, ErrorAction, LanguageClientOptions,
    Middleware, NotificationType, RequestType0,
    ResolveCodeLensSignature, RevealOutputChannelOn
} from "vscode-languageclient";
import { LanguageClient, StreamInfo } from "vscode-languageclient/node";

import { GitHubReleaseInformation, InvokePowerShellUpdateCheck } from "./features/UpdatePowerShell";
import {
    getPlatformDetails, IPlatformDetails, IPowerShellExeDetails,
    OperatingSystem, PowerShellExeFinder
} from "./platform";
import { LanguageClientConsumer } from "./languageClientConsumer";

export enum SessionStatus {
    NeverStarted,
    NotStarted,
    Initializing,
    Running,
    Stopping,
    Failed,
}

export interface IEditorServicesSessionDetails {
    status: string;
    reason: string;
    detail: string;
    powerShellVersion: string;
    channel: string;
    languageServicePort: number;
    debugServicePort: number;
    languageServicePipeName: string;
    debugServicePipeName: string;
}

export type IReadSessionFileCallback = (details: IEditorServicesSessionDetails) => void;

export class SessionManager implements Middleware {
    public HostName: string;
    public HostVersion: string;
    public PowerShellExeDetails: IPowerShellExeDetails;
    private ShowSessionMenuCommandName = "PowerShell.ShowSessionMenu";
    private editorServicesArgs: string;
    private sessionStatus: SessionStatus = SessionStatus.NeverStarted;
    private suppressRestartPrompt: boolean;
    private focusConsoleOnExecute: boolean;
    private platformDetails: IPlatformDetails;
    private languageClientConsumers: LanguageClientConsumer[] = [];
    // @ts-ignore TODO: Don't ignore after we update our engine.
    private languageStatusItem: vscode.LanguageStatusItem;
    private statusBarItem: vscode.StatusBarItem;
    private languageServerProcess: PowerShellProcess;
    private debugSessionProcess: PowerShellProcess;
    private debugEventHandler: vscode.Disposable;
    private versionDetails: IPowerShellVersionDetails;
    private registeredCommands: vscode.Disposable[] = [];
    private languageServerClient: LanguageClient = undefined;
    private sessionSettings: Settings.ISettings = undefined;
    private sessionDetails: IEditorServicesSessionDetails;
    private sessionsFolder: vscode.Uri;
    private bundledModulesPath: string;
    private started: boolean = false;

    // Initialized by the start() method, since this requires settings
    private powershellExeFinder: PowerShellExeFinder;

    constructor(
        private extensionContext: vscode.ExtensionContext,
        private log: Logger,
        private documentSelector: DocumentSelector,
        hostName: string,
        version: string,
        private telemetryReporter: TelemetryReporter) {

        // Create a folder for the session files.
        this.sessionsFolder = vscode.Uri.joinPath(extensionContext.globalStorageUri, "sessions");
        vscode.workspace.fs.createDirectory(this.sessionsFolder);

        this.platformDetails = getPlatformDetails();

        this.HostName = hostName;
        this.HostVersion = version;

        const osBitness = this.platformDetails.isOS64Bit ? "64-bit" : "32-bit";
        const procBitness = this.platformDetails.isProcess64Bit ? "64-bit" : "32-bit";

        this.log.write(
            `Visual Studio Code v${vscode.version} ${procBitness}`,
            `${this.HostName} Extension v${this.HostVersion}`,
            `Operating System: ${OperatingSystem[this.platformDetails.operatingSystem]} ${osBitness}`);

        // Fix the host version so that PowerShell can consume it.
        // This is needed when the extension uses a prerelease
        // version string like 0.9.1-insiders-1234.
        this.HostVersion = this.HostVersion.split("-")[0];

        this.registerCommands();
    }

    public dispose(): void {
        // Stop the current session
        this.stop();

        // Dispose of all commands
        this.registeredCommands.forEach((command) => { command.dispose(); });
    }

    public setLanguageClientConsumers(languageClientConsumers: LanguageClientConsumer[]) {
        this.languageClientConsumers = languageClientConsumers;
    }

    public async start(exeNameOverride?: string) {
        await Settings.validateCwdSetting();
        this.sessionSettings = Settings.load();

        if (exeNameOverride) {
            this.sessionSettings.powerShellDefaultVersion = exeNameOverride;
        }

        await this.log.startNewLog(this.sessionSettings.developer.editorServicesLogLevel);

        // Create the PowerShell executable finder now
        this.powershellExeFinder = new PowerShellExeFinder(
            this.platformDetails,
            this.sessionSettings.powerShellAdditionalExePaths);

        this.focusConsoleOnExecute = this.sessionSettings.integratedConsole.focusConsoleOnExecute;

        this.createStatusBarItem();

        this.promptPowerShellExeSettingsCleanup();

        this.migrateWhitespaceAroundPipeSetting();

        try {
            let powerShellExeDetails;
            if (this.sessionSettings.powerShellDefaultVersion) {
                for (const details of this.powershellExeFinder.enumeratePowerShellInstallations()) {
                    // Need to compare names case-insensitively, from https://stackoverflow.com/a/2140723
                    const wantedName = this.sessionSettings.powerShellDefaultVersion;
                    if (wantedName.localeCompare(details.displayName, undefined, { sensitivity: "accent" }) === 0) {
                        powerShellExeDetails = details;
                        break;
                    }
                }
            }

            this.PowerShellExeDetails = powerShellExeDetails ||
                this.powershellExeFinder.getFirstAvailablePowerShellInstallation();

        } catch (e) {
            this.log.writeError(`Error occurred while searching for a PowerShell executable:\n${e}`);
        }

        this.suppressRestartPrompt = false;

        if (!this.PowerShellExeDetails) {
            const message = "Unable to find PowerShell."
                + " Do you have PowerShell installed?"
                + " You can also configure custom PowerShell installations"
                + " with the 'powershell.powerShellAdditionalExePaths' setting.";

            this.log.writeAndShowErrorWithActions(message, [
                {
                    prompt: "Get PowerShell",
                    action: async () => {
                        const getPSUri = vscode.Uri.parse("https://aka.ms/get-powershell-vscode");
                        vscode.env.openExternal(getPSUri);
                    },
                },
            ]);
            return;
        }

        this.bundledModulesPath = path.resolve(__dirname, this.sessionSettings.bundledModulesPath);

        if (this.extensionContext.extensionMode === vscode.ExtensionMode.Development) {
            const devBundledModulesPath =
                path.resolve(
                    __dirname,
                    this.sessionSettings.developer.bundledModulesPath);

            // Make sure the module's bin path exists
            if (fs.existsSync(path.join(devBundledModulesPath, "PowerShellEditorServices/bin"))) {
                this.bundledModulesPath = devBundledModulesPath;
            } else {
                this.log.write(
                    "\nWARNING: In development mode but PowerShellEditorServices dev module path cannot be " +
                    `found (or has not been built yet): ${devBundledModulesPath}\n`);
            }
        }

        this.editorServicesArgs =
            `-HostName 'Visual Studio Code Host' ` +
            `-HostProfileId 'Microsoft.VSCode' ` +
            `-HostVersion '${this.HostVersion}' ` +
            `-AdditionalModules @('PowerShellEditorServices.VSCode') ` +
            `-BundledModulesPath '${PowerShellProcess.escapeSingleQuotes(this.bundledModulesPath)}' ` +
            `-EnableConsoleRepl `;

        if (this.sessionSettings.integratedConsole.suppressStartupBanner) {
            this.editorServicesArgs += "-StartupBanner '' ";
        } else {
            const startupBanner = `${this.HostName} Extension v${this.HostVersion}
Copyright (c) Microsoft Corporation.

https://aka.ms/vscode-powershell
Type 'help' to get help.
`;
            this.editorServicesArgs += `-StartupBanner "${startupBanner}" `;
        }

        if (this.sessionSettings.developer.editorServicesWaitForDebugger) {
            this.editorServicesArgs += "-WaitForDebugger ";
        }
        if (this.sessionSettings.developer.editorServicesLogLevel) {
            this.editorServicesArgs += `-LogLevel '${this.sessionSettings.developer.editorServicesLogLevel}' `;
        }

        this.startPowerShell();
    }

    public stop() {

        // Shut down existing session if there is one
        this.log.write("Shutting down language client...");

        if (this.sessionStatus === SessionStatus.Failed) {
            // Before moving further, clear out the client and process if
            // the process is already dead (i.e. it crashed)
            this.languageServerClient = undefined;
            this.languageServerProcess = undefined;
        }

        this.sessionStatus = SessionStatus.Stopping;

        // Close the language server client
        if (this.languageServerClient !== undefined) {
            this.languageServerClient.stop();
            this.languageServerClient = undefined;
        }

        // Kill the PowerShell process we spawned
        if (this.debugSessionProcess) {
            this.debugSessionProcess.dispose();
            this.debugEventHandler.dispose();
        }
        if (this.languageServerProcess) {
            this.languageServerProcess.dispose();
        }

        this.sessionStatus = SessionStatus.NotStarted;
    }

    public async restartSession(exeNameOverride?: string) {
        this.stop();
        await this.start(exeNameOverride);
    }

    public getSessionDetails(): IEditorServicesSessionDetails {
        return this.sessionDetails;
    }

    public getSessionStatus(): SessionStatus {
        return this.sessionStatus;
    }

    public getPowerShellVersionDetails(): IPowerShellVersionDetails {
        return this.versionDetails;
    }

    public getNewSessionFilePath(): vscode.Uri {
        const uniqueId: number = Math.floor(100000 + Math.random() * 900000);
        return vscode.Uri.joinPath(this.sessionsFolder, "PSES-VSCode-" + process.env.VSCODE_PID + "-" + uniqueId + ".json");
    }

    public createDebugSessionProcess(sessionSettings: Settings.ISettings): PowerShellProcess {

        // NOTE: We only support one temporary Extension Terminal at a time. To
        // support more, we need to track each separately, and tie the session
        // for the event handler to the right process (and dispose of the event
        // handler when the process is disposed).
        if (this.debugSessionProcess) {
            this.debugSessionProcess.dispose()
            this.debugEventHandler.dispose();
        }

        this.debugSessionProcess =
            new PowerShellProcess(
                this.PowerShellExeDetails.exePath,
                this.bundledModulesPath,
                "[TEMP] PowerShell Extension",
                this.log,
                this.editorServicesArgs + "-DebugServiceOnly ",
                this.getNewSessionFilePath(),
                sessionSettings);

        // Similar to the regular Extension Terminal, we need to send a key
        // press to the process spawned for temporary Extension Terminals when
        // the server requests a cancellation os Console.ReadKey.
        this.debugEventHandler = vscode.debug.onDidReceiveDebugSessionCustomEvent(
            e => {
                if (e.event === "powerShell/sendKeyPress") {
                    this.debugSessionProcess.sendKeyPress();
                }
            }
        );

        return this.debugSessionProcess;
    }

    public async waitUntilStarted(): Promise<void> {
        while (!this.started) {
            await utils.sleep(300);
        }
    }

    // ----- LanguageClient middleware methods -----

    public resolveCodeLens(
        codeLens: vscode.CodeLens,
        token: vscode.CancellationToken,
        next: ResolveCodeLensSignature): vscode.ProviderResult<vscode.CodeLens> {
        const resolvedCodeLens = next(codeLens, token);
        const resolveFunc =
            (codeLensToFix: vscode.CodeLens): vscode.CodeLens => {
                if (codeLensToFix.command?.command === "editor.action.showReferences") {
                    const oldArgs = codeLensToFix.command.arguments;

                    // Our JSON objects don't get handled correctly by
                    // VS Code's built in editor.action.showReferences
                    // command so we need to convert them into the
                    // appropriate types to send them as command
                    // arguments.

                    codeLensToFix.command.arguments = [
                        vscode.Uri.parse(oldArgs[0]),
                        new vscode.Position(oldArgs[1].line, oldArgs[1].character),
                        oldArgs[2].map((position) => {
                            return new vscode.Location(
                                vscode.Uri.parse(position.uri),
                                new vscode.Range(
                                    position.range.start.line,
                                    position.range.start.character,
                                    position.range.end.line,
                                    position.range.end.character));
                        }),
                    ];
                }

                return codeLensToFix;
            };

        if ((resolvedCodeLens as Thenable<vscode.CodeLens>).then) {
            return (resolvedCodeLens as Thenable<vscode.CodeLens>).then(resolveFunc);
        } else if (resolvedCodeLens as vscode.CodeLens) {
            return resolveFunc(resolvedCodeLens as vscode.CodeLens);
        }

        return resolvedCodeLens;
    }

    // Move old setting codeFormatting.whitespaceAroundPipe to new setting codeFormatting.addWhitespaceAroundPipe
    private async migrateWhitespaceAroundPipeSetting() {
        const configuration = vscode.workspace.getConfiguration(utils.PowerShellLanguageId);
        const deprecatedSetting = 'codeFormatting.whitespaceAroundPipe'
        const newSetting = 'codeFormatting.addWhitespaceAroundPipe'
        const configurationTargetOfNewSetting = await Settings.getEffectiveConfigurationTarget(newSetting);
        const configurationTargetOfOldSetting = await Settings.getEffectiveConfigurationTarget(deprecatedSetting);
        if (configurationTargetOfOldSetting !== null && configurationTargetOfNewSetting === null) {
            const value = configuration.get(deprecatedSetting, configurationTargetOfOldSetting)
            await Settings.change(newSetting, value, configurationTargetOfOldSetting);
            await Settings.change(deprecatedSetting, undefined, configurationTargetOfOldSetting);
        }
    }

    private async promptPowerShellExeSettingsCleanup() {
        if (this.sessionSettings.powerShellExePath) {
            let warningMessage = "The 'powerShell.powerShellExePath' setting is no longer used. ";
            warningMessage += this.sessionSettings.powerShellDefaultVersion
                ? "We can automatically remove it for you."
                : "We can remove it from your settings and prompt you for which PowerShell you want to use.";

            const choice = await vscode.window.showWarningMessage(warningMessage, "Let's do it!");

            if (choice === undefined) {
                // They hit the 'x' to close the dialog.
                return;
            }

            this.suppressRestartPrompt = true;
            try {
                await Settings.change("powerShellExePath", undefined, true);
            } finally {
                this.suppressRestartPrompt = false;
            }

            // Show the session menu at the end if they don't have a PowerShellDefaultVersion.
            if (!this.sessionSettings.powerShellDefaultVersion) {
                await vscode.commands.executeCommand(this.ShowSessionMenuCommandName);
            }
        }
    }

    private async onConfigurationUpdated() {
        const settings = Settings.load();

        this.focusConsoleOnExecute = settings.integratedConsole.focusConsoleOnExecute;

        // Detect any setting changes that would affect the session
        if (!this.suppressRestartPrompt &&
            (settings.cwd?.toLowerCase() !==
                this.sessionSettings.cwd?.toLowerCase() ||
                settings.powerShellDefaultVersion.toLowerCase() !==
                this.sessionSettings.powerShellDefaultVersion.toLowerCase() ||
            settings.developer.editorServicesLogLevel.toLowerCase() !==
                this.sessionSettings.developer.editorServicesLogLevel.toLowerCase() ||
            settings.developer.bundledModulesPath.toLowerCase() !==
                this.sessionSettings.developer.bundledModulesPath.toLowerCase() ||
            settings.integratedConsole.useLegacyReadLine !==
                this.sessionSettings.integratedConsole.useLegacyReadLine)) {

            const response: string = await vscode.window.showInformationMessage(
                "The PowerShell runtime configuration has changed, would you like to start a new session?",
                "Yes", "No");

            if (response === "Yes") {
                await this.restartSession();
            }
        }
    }

    private setStatusBarVersionString(runspaceDetails: IRunspaceDetails) {
        const psVersion = runspaceDetails.powerShellVersion;

        let versionString =
            this.versionDetails.architecture === "x86"
                ? `${psVersion.displayVersion} (${psVersion.architecture})`
                : psVersion.displayVersion;

        if (runspaceDetails.runspaceType !== RunspaceType.Local) {
            versionString += ` [${runspaceDetails.connectionString}]`;
        }

        this.setSessionVersion(versionString);
    }

    private registerCommands(): void {
        this.registeredCommands = [
            vscode.commands.registerCommand("PowerShell.RestartSession", () => { this.restartSession(); }),
            vscode.commands.registerCommand(this.ShowSessionMenuCommandName, () => { this.showSessionMenu(); }),
            vscode.workspace.onDidChangeConfiguration(async () => { await this.onConfigurationUpdated(); }),
            vscode.commands.registerCommand(
                "PowerShell.ShowSessionConsole", (isExecute?: boolean) => { this.showSessionConsole(isExecute); }),
        ];
    }

    private startPowerShell() {
        this.setSessionStatus("Starting...", SessionStatus.Initializing);

        this.languageServerProcess =
            new PowerShellProcess(
                this.PowerShellExeDetails.exePath,
                this.bundledModulesPath,
                "PowerShell Extension",
                this.log,
                this.editorServicesArgs,
                this.getNewSessionFilePath(),
                this.sessionSettings);

        this.languageServerProcess.onExited(
            async () => {
                if (this.sessionStatus === SessionStatus.Running) {
                    this.setSessionStatus("Session Exited", SessionStatus.Failed);
                    await this.promptForRestart();
                }
            });

        this.languageServerProcess
            .start("EditorServices")
            .then(
                (sessionDetails) => {
                    this.sessionDetails = sessionDetails;

                    if (sessionDetails.status === "started") {
                        this.log.write("Language server started.");

                        // Start the language service client
                        this.startLanguageClient(sessionDetails);
                    } else if (sessionDetails.status === "failed") {
                        if (sessionDetails.reason === "unsupported") {
                            this.setSessionFailure(
                                "PowerShell language features are only supported on PowerShell version 5.1 and 6.1" +
                                ` and above. The current version is ${sessionDetails.powerShellVersion}.`);
                        } else if (sessionDetails.reason === "languageMode") {
                            this.setSessionFailure(
                                "PowerShell language features are disabled due to an unsupported LanguageMode: " +
                                `${sessionDetails.detail}`);
                        } else {
                            this.setSessionFailure(
                                `PowerShell could not be started for an unknown reason '${sessionDetails.reason}'`);
                        }
                    } else {
                        // TODO: Handle other response cases
                    }
                },
                (error) => {
                    this.log.write("Language server startup failed.");
                    this.setSessionFailure("The language service could not be started: ", error);
                },
            )
            .catch((error) => {
                this.log.write("Language server startup failed.");
                this.setSessionFailure("The language server could not be started: ", error);
            });
    }

    private async promptForRestart() {
        const response: string = await vscode.window.showErrorMessage(
            "The PowerShell Extension Terminal has stopped, would you like to restart it? IntelliSense and other features will not work without it!",
            "Yes", "No");

        if (response === "Yes") {
            await this.restartSession();
        }
    }

    private startLanguageClient(sessionDetails: IEditorServicesSessionDetails) {
        // Log the session details object
        this.log.write(JSON.stringify(sessionDetails));

        try {
            this.log.write(`Connecting to language service on pipe ${sessionDetails.languageServicePipeName}...`);

            const connectFunc = () => {
                return new Promise<StreamInfo>(
                    (resolve, reject) => {
                        const socket = net.connect(sessionDetails.languageServicePipeName);
                        socket.on(
                            "connect",
                            () => {
                                this.log.write("Language service connected.");
                                resolve({ writer: socket, reader: socket });
                            });
                    });
            };

            const clientOptions: LanguageClientOptions = {
                documentSelector: this.documentSelector,
                synchronize: {
                    // backend uses "files" and "search" to ignore references.
                    configurationSection: [utils.PowerShellLanguageId, "files", "search"],
                    // fileEvents: vscode.workspace.createFileSystemWatcher('**/.eslintrc')
                },
                // NOTE: Some settings are only applicable on startup, so we send them during initialization.
                initializationOptions: {
                    enableProfileLoading: this.sessionSettings.enableProfileLoading,
                    initialWorkingDirectory: this.sessionSettings.cwd,
                },
                errorHandler: {
                    // Override the default error handler to prevent it from
                    // closing the LanguageClient incorrectly when the socket
                    // hangs up (ECONNRESET errors).
                    error: (error: any, message: Message, count: number): ErrorAction => {
                        // TODO: Is there any error worth terminating on?
                        return ErrorAction.Continue;
                    },
                    closed: () => {
                        // We have our own restart experience
                        return CloseAction.DoNotRestart;
                    },
                },
                revealOutputChannelOn: RevealOutputChannelOn.Never,
                middleware: this,
            };

            this.languageServerClient =
                new LanguageClient(
                    "PowerShell Editor Services",
                    connectFunc,
                    clientOptions);

            // This enables handling Semantic Highlighting messages in PowerShell Editor Services
            this.languageServerClient.registerProposedFeatures();

            if (this.extensionContext.extensionMode === vscode.ExtensionMode.Production) {
                this.languageServerClient.onTelemetry((event) => {
                    const eventName: string = event.eventName ? event.eventName : "PSESEvent";
                    const data: any = event.data ? event.data : event
                    this.telemetryReporter.sendTelemetryEvent(eventName, data);
                });
            }

            this.languageServerClient.onReady().then(
                () => {
                    this.languageServerClient
                        .sendRequest(PowerShellVersionRequestType)
                        .then(
                            async (versionDetails) => {
                                this.versionDetails = versionDetails;
                                this.started = true;

                                if (this.extensionContext.extensionMode === vscode.ExtensionMode.Production) {
                                    this.telemetryReporter.sendTelemetryEvent("powershellVersionCheck",
                                        { powershellVersion: versionDetails.version });
                                }

                                this.setSessionVersion(
                                    this.versionDetails.architecture === "x86"
                                        ? `${this.versionDetails.displayVersion} (${this.versionDetails.architecture})`
                                        : this.versionDetails.displayVersion);

                                // If the user opted to not check for updates, then don't.
                                if (!this.sessionSettings.promptToUpdatePowerShell) { return; }

                                try {
                                    const localVersion = semver.parse(this.versionDetails.version);
                                    if (semver.lt(localVersion, "6.0.0")) {
                                        // Skip prompting when using Windows PowerShell for now.
                                        return;
                                    }

                                    // Fetch the latest PowerShell releases from GitHub.
                                    const isPreRelease = !!semver.prerelease(localVersion);
                                    const release: GitHubReleaseInformation =
                                        await GitHubReleaseInformation.FetchLatestRelease(isPreRelease);

                                    await InvokePowerShellUpdateCheck(
                                        this,
                                        this.languageServerClient,
                                        localVersion,
                                        this.versionDetails.architecture,
                                        release);
                                } catch (e) {
                                    // best effort. This probably failed to fetch the data from GitHub.
                                    this.log.writeWarning(e.message);
                                }
                            });

                    // Send the new LanguageClient to extension features
                    // so that they can register their message handlers
                    // before the connection is established.
                    this.updateLanguageClientConsumers(this.languageServerClient);
                    this.languageServerClient.onNotification(
                        RunspaceChangedEventType,
                        (runspaceDetails) => { this.setStatusBarVersionString(runspaceDetails); });

                    // NOTE: This fixes a quirk where PSES has a thread stuck on
                    // Console.ReadKey, since it's not cancellable. On
                    // "cancellation" the server asks us to send pretend to
                    // press a key, thus mitigating all the quirk.
                    this.languageServerClient.onNotification(
                        SendKeyPressNotificationType,
                        () => { this.languageServerProcess.sendKeyPress(); });
                },
                (reason) => {
                    this.setSessionFailure("Could not start language service: ", reason);
                });

            this.languageServerClient.start();
        } catch (e) {
            this.setSessionFailure("The language service could not be started: ", e);
        }
    }

    private updateLanguageClientConsumers(languageClient: LanguageClient) {
        this.languageClientConsumers.forEach((feature) => {
            feature.setLanguageClient(languageClient);
        });
    }

    private createStatusBarItem() {
        const statusTitle: string = "Show PowerShell Session Menu";
        // TODO: Remove old status bar logic when we update our engine.
        if (semver.gte(vscode.version, "1.65.0") && this.languageStatusItem === undefined) {
            // @ts-ignore
            this.languageStatusItem = vscode.languages.createLanguageStatusItem("powershell", this.documentSelector);
            this.languageStatusItem.command = { title: statusTitle, command: this.ShowSessionMenuCommandName };
            this.languageStatusItem.text = "$(terminal-powershell)";
        } else if (this.statusBarItem === undefined) {
            // Create the status bar item and place it right next
            // to the language indicator
            this.statusBarItem =
                vscode.window.createStatusBarItem(
                    vscode.StatusBarAlignment.Right,
                    1);

            this.statusBarItem.command = this.ShowSessionMenuCommandName;
            this.statusBarItem.tooltip = statusTitle;
            this.statusBarItem.show();
            vscode.window.onDidChangeActiveTextEditor((textEditor) => {
                if (textEditor === undefined
                    || textEditor.document.languageId !== "powershell") {
                    this.statusBarItem.hide();
                } else {
                    this.statusBarItem.show();
                }
            });
        }
    }

    private setSessionStatus(statusText: string, status: SessionStatus): void {
        this.sessionStatus = status;
        // TODO: Remove old status bar logic when we update our engine.
        if (semver.gte(vscode.version, "1.65.0")) {
            this.languageStatusItem.detail = "PowerShell " + statusText;
            switch (status) {
                case SessionStatus.Running:
                case SessionStatus.NeverStarted:
                case SessionStatus.NotStarted:
                    this.languageStatusItem.busy = false;
                    // @ts-ignore
                    this.languageStatusItem.severity = vscode.LanguageStatusSeverity.Information;
                    break;
                case SessionStatus.Initializing:
                case SessionStatus.Stopping:
                    this.languageStatusItem.busy = true;
                    // @ts-ignore
                    this.languageStatusItem.severity = vscode.LanguageStatusSeverity.Warning;
                    break;
                case SessionStatus.Failed:
                    this.languageStatusItem.busy = false;
                    // @ts-ignore
                    this.languageStatusItem.severity = vscode.LanguageStatusSeverity.Error;
                    break;
            }
        } else {
            switch (status) {
                case SessionStatus.Running:
                case SessionStatus.NeverStarted:
                case SessionStatus.NotStarted:
                    this.statusBarItem.text = "$(terminal-powershell)";
                    // These have to be reset because this function mutates state.
                    this.statusBarItem.color = undefined;
                    this.statusBarItem.backgroundColor = undefined;
                    break;
                case SessionStatus.Initializing:
                case SessionStatus.Stopping:
                    this.statusBarItem.text = "$(sync)";
                    this.statusBarItem.color = new vscode.ThemeColor("statusBarItem.warningForeground");
                    this.statusBarItem.backgroundColor = new vscode.ThemeColor("statusBarItem.warningBackground");
                    break;
                case SessionStatus.Failed:
                    this.statusBarItem.text = "$(alert)";
                    this.statusBarItem.color = new vscode.ThemeColor("statusBarItem.errorForeground");
                    this.statusBarItem.backgroundColor = new vscode.ThemeColor("statusBarItem.errorBackground");
                    break;
            }
            this.statusBarItem.text += " " + statusText;
        }
    }

    private setSessionVersion(version: string): void {
        // TODO: Accept a VersionDetails object instead of a string.
        if (semver.gte(vscode.version, "1.65.0")) {
            this.languageStatusItem.text = "$(terminal-powershell) " + version;
        }
        this.setSessionStatus(version, SessionStatus.Running);
    }

    private setSessionFailure(message: string, ...additionalMessages: string[]) {
        this.log.writeAndShowError(message, ...additionalMessages);
        this.setSessionStatus("Initialization Error", SessionStatus.Failed);
    }

    private async changePowerShellDefaultVersion(exePath: IPowerShellExeDetails) {
        this.suppressRestartPrompt = true;
        await Settings.change("powerShellDefaultVersion", exePath.displayName, true);

        // We pass in the display name so that we force the extension to use that version
        // rather than pull from the settings. The issue we prevent here is when a
        // workspace setting is defined which gets priority over user settings which
        // is what the change above sets.
        await this.restartSession(exePath.displayName);
    }

    private showSessionConsole(isExecute?: boolean) {
        if (this.languageServerProcess) {
            this.languageServerProcess.showConsole(isExecute && !this.focusConsoleOnExecute);
        }
    }

    private showSessionMenu() {
        const availablePowerShellExes = this.powershellExeFinder.getAllAvailablePowerShellInstallations();

        let sessionText: string;

        switch (this.sessionStatus) {
            case SessionStatus.Running:
            case SessionStatus.Initializing:
            case SessionStatus.NotStarted:
            case SessionStatus.NeverStarted:
            case SessionStatus.Stopping:
                const currentPowerShellExe =
                    availablePowerShellExes
                        .find((item) => item.displayName.toLowerCase() === this.PowerShellExeDetails.displayName.toLowerCase());

                const powerShellSessionName =
                    currentPowerShellExe ?
                        currentPowerShellExe.displayName :
                        `PowerShell ${this.versionDetails.displayVersion} ` +
                        `(${this.versionDetails.architecture}) ${this.versionDetails.edition} Edition ` +
                        `[${this.versionDetails.version}]`;

                sessionText = `Current session: ${powerShellSessionName}`;
                break;

            case SessionStatus.Failed:
                sessionText = "Session initialization failed, click here to show PowerShell extension logs";
                break;

            default:
                throw new TypeError("Not a valid value for the enum 'SessionStatus'");
        }

        const powerShellItems =
            availablePowerShellExes
                .filter((item) => item.displayName !== this.PowerShellExeDetails.displayName)
                .map((item) => {
                    return new SessionMenuItem(
                        `Switch to: ${item.displayName}`,
                        () => { this.changePowerShellDefaultVersion(item); });
                });

        const menuItems: SessionMenuItem[] = [
            new SessionMenuItem(
                sessionText,
                () => { vscode.commands.executeCommand("PowerShell.ShowLogs"); }),

            // Add all of the different PowerShell options
            ...powerShellItems,

            new SessionMenuItem(
                "Restart Current Session",
                async () => {
                    // We pass in the display name so we guarantee that the session
                    // will be the same PowerShell.
                    await this.restartSession(this.PowerShellExeDetails.displayName);
                }),

            new SessionMenuItem(
                "Open Session Logs Folder",
                () => { vscode.commands.executeCommand("PowerShell.OpenLogFolder"); }),

            new SessionMenuItem(
                "Modify list of additional PowerShell locations",
                () => { vscode.commands.executeCommand("workbench.action.openSettings", "powerShellAdditionalExePaths"); }),
        ];

        vscode
            .window
            .showQuickPick<SessionMenuItem>(menuItems)
            .then((selectedItem) => { selectedItem.callback(); });
    }
}

class SessionMenuItem implements vscode.QuickPickItem {
    public description: string;

    constructor(
        public readonly label: string,
        // tslint:disable-next-line:no-empty
        public readonly callback: () => void = () => { }) {
    }
}

export const SendKeyPressNotificationType =
    new NotificationType<void>("powerShell/sendKeyPress");

export const PowerShellVersionRequestType =
    new RequestType0<IPowerShellVersionDetails, void>(
        "powerShell/getVersion");

export const RunspaceChangedEventType =
    new NotificationType<IRunspaceDetails>(
        "powerShell/runspaceChanged");

export enum RunspaceType {
    Local,
    Process,
    Remote,
}

export interface IPowerShellVersionDetails {
    version: string;
    displayVersion: string;
    edition: string;
    architecture: string;
}

export interface IRunspaceDetails {
    powerShellVersion: IPowerShellVersionDetails;
    runspaceType: RunspaceType;
    connectionString: string;
}