Add login page.

Marechai.App/Presentation/ViewModels/LoginViewModel.cs

@@ -0,0 +1,93 @@
+#nullable enable
+
+using System;
+using System.Collections.Generic;
+using System.Threading;
+using System.Threading.Tasks;
+using Uno.Extensions.Authentication;
+using Uno.Extensions.Navigation;
+
+namespace Marechai.App.Presentation.ViewModels;
+
+public partial class LoginViewModel : ObservableObject
+{
+    private readonly IAuthenticationService _authService;
+    private readonly INavigator             _navigator;
+    private readonly IStringLocalizer       _stringLocalizer;
+
+    [ObservableProperty]
+    private string _email = string.Empty;
+    [ObservableProperty]
+    private string? _errorMessage;
+    [ObservableProperty]
+    private bool _isLoggingIn;
+    [ObservableProperty]
+    private string _password = string.Empty;
+
+    public LoginViewModel(INavigator navigator, IAuthenticationService authService, IStringLocalizer stringLocalizer)
+    {
+        _navigator       = navigator;
+        _authService     = authService;
+        _stringLocalizer = stringLocalizer;
+    }
+
+    [RelayCommand]
+    private async Task LoginAsync()
+    {
+        // Clear previous error
+        ErrorMessage = null;
+
+        // Validate inputs
+        if(string.IsNullOrWhiteSpace(Email))
+        {
+            ErrorMessage = _stringLocalizer["LoginPage.Error.EmailRequired"];
+
+            return;
+        }
+
+        if(string.IsNullOrWhiteSpace(Password))
+        {
+            ErrorMessage = _stringLocalizer["LoginPage.Error.PasswordRequired"];
+
+            return;
+        }
+
+        IsLoggingIn = true;
+
+        try
+        {
+            var credentials = new Dictionary<string, string>
+            {
+                ["Email"]    = Email,
+                ["Password"] = Password
+            };
+
+            bool success = await _authService.LoginAsync(null, credentials, null, CancellationToken.None);
+
+            if(success)
+            {
+                // Navigate back to main page on successful login
+                await _navigator.NavigateRouteAsync(this, "/Main");
+            }
+            else
+            {
+                // Check if there's an error message in credentials
+                if(credentials.TryGetValue("error", out string? error))
+                    ErrorMessage = error;
+                else
+                    ErrorMessage = _stringLocalizer["LoginPage.Error.LoginFailed"];
+            }
+        }
+        catch(Exception ex)
+        {
+            ErrorMessage = ex.Message;
+        }
+        finally
+        {
+            IsLoggingIn = false;
+        }
+    }
+
+    [RelayCommand]
+    private void ClearError() => ErrorMessage = null;
+}