oauth-ui: Add shared VMs and commands for OAuth

Add shared view models and commands for the OAuth GUI prompts.

Two new commands and VMs are added, one for the initial 'mode'
selection, and another to display the device code.

Author: mjcheetham

src/shared/Core.UI/Commands/DeviceCodeCommand.cs

@@ -0,0 +1,52 @@
+using System;
+using System.CommandLine;
+using System.CommandLine.Invocation;
+using System.Threading;
+using System.Threading.Tasks;
+using GitCredentialManager.UI.ViewModels;
+
+namespace GitCredentialManager.UI.Commands
+{
+    public abstract class DeviceCodeCommand : HelperCommand
+    {
+        protected DeviceCodeCommand(ICommandContext context)
+            : base(context, "device", "Show device code prompt.")
+        {
+            AddOption(
+                new Option<string>("--code", "User code.")
+            );
+
+            AddOption(
+                new Option<string>("--url", "Verification URL.")
+            );
+
+            AddOption(
+                new Option("--no-logo", "Hide the Git Credential Manager logo and logotype.")
+            );
+
+            Handler = CommandHandler.Create<string, string, bool>(ExecuteAsync);
+        }
+
+        private async Task<int> ExecuteAsync(string code, string url, bool noLogo)
+        {
+            var viewModel = new DeviceCodeViewModel(Context.Environment)
+            {
+                UserCode = code,
+                VerificationUrl = url,
+            };
+
+            viewModel.ShowProductHeader = !noLogo;
+
+            await ShowAsync(viewModel, CancellationToken.None);
+
+            if (!viewModel.WindowResult)
+            {
+                throw new Exception("User cancelled dialog.");
+            }
+
+            return 0;
+        }
+
+        protected abstract Task ShowAsync(DeviceCodeViewModel viewModel, CancellationToken ct);
+    }
+}

src/shared/Core.UI/Commands/OAuthCommand.cs

@@ -0,0 +1,93 @@
+using System;
+using System.Collections.Generic;
+using System.CommandLine;
+using System.CommandLine.Invocation;
+using System.Threading;
+using System.Threading.Tasks;
+using GitCredentialManager.Authentication;
+using GitCredentialManager.UI.ViewModels;
+
+namespace GitCredentialManager.UI.Commands
+{
+    public abstract class OAuthCommand : HelperCommand
+    {
+        protected OAuthCommand(ICommandContext context)
+            : base(context, "oauth", "Show OAuth authentication prompt.")
+        {
+            AddOption(
+                new Option<string>("--title", "Window title (optional).")
+            );
+
+            AddOption(
+                new Option<string>("--resource", "Resource name or URL (optional).")
+            );
+
+            AddOption(
+                new Option("--browser", "Show browser authentication option.")
+            );
+
+            AddOption(
+                new Option("--device-code", "Show device code authentication option.")
+            );
+
+            AddOption(
+                new Option("--no-logo", "Hide the Git Credential Manager logo and logotype.")
+            );
+
+            Handler = CommandHandler.Create<CommandOptions>(ExecuteAsync);
+        }
+
+        private class CommandOptions
+        {
+            public string Title { get; set; }
+            public string Resource { get; set; }
+            public bool Browser { get; set; }
+            public bool DeviceCode { get; set; }
+            public bool NoLogo { get; set; }
+        }
+
+        private async Task<int> ExecuteAsync(CommandOptions options)
+        {
+            var viewModel = new OAuthViewModel();
+
+            viewModel.Title = !string.IsNullOrWhiteSpace(options.Title)
+                ? options.Title
+                : "Git Credential Manager";
+
+            viewModel.Description = !string.IsNullOrWhiteSpace(options.Resource)
+                ? $"Sign in to '{options.Resource}'"
+                : "Select a sign-in option";
+
+            viewModel.ShowBrowserLogin = options.Browser;
+            viewModel.ShowDeviceCodeLogin = options.DeviceCode;
+            viewModel.ShowProductHeader = !options.NoLogo;
+
+            await ShowAsync(viewModel, CancellationToken.None);
+
+            if (!viewModel.WindowResult)
+            {
+                throw new Exception("User cancelled dialog.");
+            }
+
+            var result = new Dictionary<string, string>();
+            switch (viewModel.SelectedMode)
+            {
+                case OAuthAuthenticationModes.Browser:
+                    result["mode"] = "browser";
+                    break;
+
+                case OAuthAuthenticationModes.DeviceCode:
+                    result["mode"] = "devicecode";
+                    break;
+
+                default:
+                    throw new ArgumentOutOfRangeException();
+            }
+
+            WriteResult(result);
+            return 0;
+        }
+
+        protected abstract Task ShowAsync(OAuthViewModel viewModel, CancellationToken ct);
+    }
+}

src/shared/Core.UI/ViewModels/DeviceCodeViewModel.cs

@@ -0,0 +1,58 @@
+using System.Windows.Input;
+
+namespace GitCredentialManager.UI.ViewModels
+{
+    public class DeviceCodeViewModel : WindowViewModel
+    {
+        private readonly IEnvironment _environment;
+
+        private ICommand _verificationUrlCommand;
+        private string _verificationUrl;
+        private string _userCode;
+        private bool _showProductHeader;
+
+        public DeviceCodeViewModel()
+        {
+            // Constructor the XAML designer
+        }
+
+        public DeviceCodeViewModel(IEnvironment environment)
+        {
+            EnsureArgument.NotNull(environment, nameof(environment));
+
+            _environment = environment;
+
+            Title = "Device code authentication";
+            VerificationUrlCommand = new RelayCommand(OpenVerificationUrl);
+        }
+
+        private void OpenVerificationUrl()
+        {
+            BrowserUtils.OpenDefaultBrowser(_environment, VerificationUrl);
+        }
+
+        public string UserCode
+        {
+            get => _userCode;
+            set => SetAndRaisePropertyChanged(ref _userCode, value);
+        }
+
+        public string VerificationUrl
+        {
+            get => _verificationUrl;
+            set => SetAndRaisePropertyChanged(ref _verificationUrl, value);
+        }
+
+        public ICommand VerificationUrlCommand
+        {
+            get => _verificationUrlCommand;
+            set => SetAndRaisePropertyChanged(ref _verificationUrlCommand, value);
+        }
+
+        public bool ShowProductHeader
+        {
+            get => _showProductHeader;
+            set => SetAndRaisePropertyChanged(ref _showProductHeader, value);
+        }
+    }
+}

src/shared/Core.UI/ViewModels/OAuthViewModel.cs

@@ -0,0 +1,70 @@
+using GitCredentialManager.Authentication;
+
+namespace GitCredentialManager.UI.ViewModels
+{
+    public class OAuthViewModel : WindowViewModel
+    {
+        private string _description;
+        private bool _showProductHeader;
+        private bool _showBrowserLogin;
+        private bool _showDeviceCodeLogin;
+        private RelayCommand _signInBrowserCommand;
+        private RelayCommand _signInDeviceCodeCommand;
+
+        public OAuthViewModel()
+        {
+            SignInBrowserCommand = new RelayCommand(SignInWithBrowser);
+            SignInDeviceCodeCommand = new RelayCommand(SignInWithDeviceCode);
+        }
+
+        private void SignInWithBrowser()
+        {
+            SelectedMode = OAuthAuthenticationModes.Browser;
+            Accept();
+        }
+
+        private void SignInWithDeviceCode()
+        {
+            SelectedMode = OAuthAuthenticationModes.DeviceCode;
+            Accept();
+        }
+
+        public string Description
+        {
+            get => _description;
+            set => SetAndRaisePropertyChanged(ref _description, value);
+        }
+
+        public bool ShowProductHeader
+        {
+            get => _showProductHeader;
+            set => SetAndRaisePropertyChanged(ref _showProductHeader, value);
+        }
+
+        public bool ShowBrowserLogin
+        {
+            get => _showBrowserLogin;
+            set => SetAndRaisePropertyChanged(ref _showBrowserLogin, value);
+        }
+
+        public bool ShowDeviceCodeLogin
+        {
+            get => _showDeviceCodeLogin;
+            set => SetAndRaisePropertyChanged(ref _showDeviceCodeLogin, value);
+        }
+
+        public RelayCommand SignInBrowserCommand
+        {
+            get => _signInBrowserCommand;
+            set => SetAndRaisePropertyChanged(ref _signInBrowserCommand, value);
+        }
+
+        public RelayCommand SignInDeviceCodeCommand
+        {
+            get => _signInDeviceCodeCommand;
+            set => SetAndRaisePropertyChanged(ref _signInDeviceCodeCommand, value);
+        }
+
+        public OAuthAuthenticationModes SelectedMode { get; private set; }
+    }
+}