public CommandContext(string appPath)
        {
            EnsureArgument.NotNullOrWhiteSpace(appPath, nameof(appPath));

            ApplicationPath = appPath;
            Streams         = new StandardStreams();
            Trace           = new Trace();

            if (PlatformUtils.IsWindows())
            {
                FileSystem     = new WindowsFileSystem();
                SessionManager = new WindowsSessionManager();
                SystemPrompts  = new WindowsSystemPrompts();
                Environment    = new WindowsEnvironment(FileSystem);
                Terminal       = new WindowsTerminal(Trace);
                string gitPath = GetGitPath(Environment, FileSystem, Trace);
                Git = new GitProcess(
                    Trace,
                    Environment,
                    gitPath,
                    FileSystem.GetCurrentDirectory()
                    );
                Settings = new WindowsSettings(Environment, Git, Trace);
            }
            else if (PlatformUtils.IsMacOS())
            {
                FileSystem     = new MacOSFileSystem();
                SessionManager = new MacOSSessionManager();
                SystemPrompts  = new MacOSSystemPrompts();
                Environment    = new PosixEnvironment(FileSystem);
                Terminal       = new MacOSTerminal(Trace);
                string gitPath = GetGitPath(Environment, FileSystem, Trace);
                Git = new GitProcess(
                    Trace,
                    Environment,
                    gitPath,
                    FileSystem.GetCurrentDirectory()
                    );
                Settings = new Settings(Environment, Git);
            }
            else if (PlatformUtils.IsLinux())
            {
                FileSystem = new LinuxFileSystem();
                // TODO: support more than just 'Posix' or X11
                SessionManager = new PosixSessionManager();
                SystemPrompts  = new LinuxSystemPrompts();
                Environment    = new PosixEnvironment(FileSystem);
                Terminal       = new LinuxTerminal(Trace);
                string gitPath = GetGitPath(Environment, FileSystem, Trace);
                Git = new GitProcess(
                    Trace,
                    Environment,
                    gitPath,
                    FileSystem.GetCurrentDirectory()
                    );
                Settings = new Settings(Environment, Git);
            }
            else
            {
                throw new PlatformNotSupportedException();
            }

            HttpClientFactory = new HttpClientFactory(FileSystem, Trace, Settings, Streams);
            CredentialStore   = new CredentialStore(this);

            // Set the parent window handle/ID
            SystemPrompts.ParentWindowId = Settings.ParentWindowId;
        }