[frontend] Add basic login flow and session management.

Iceshrimp.Frontend/App.razor

@@ -1,6 +1,13 @@
-<Router AppAssembly="@typeof(App).Assembly">
+@using Microsoft.AspNetCore.Components.Authorization
+@using Iceshrimp.Frontend.Components
+<Router AppAssembly="@typeof(App).Assembly">
     <Found Context="routeData">
-        <RouteView RouteData="@routeData" DefaultLayout="@typeof(MainLayout)"/>
+        <AuthorizeRouteView RouteData="@routeData" DefaultLayout="@typeof(MainLayout)">
+            <NotAuthorized>
+                <RedirectToLogin/>
+            </NotAuthorized>
+        </AuthorizeRouteView>
+        @* <RouteView RouteData="@routeData" DefaultLayout="@typeof(MainLayout)"/> *@
         <FocusOnNavigate RouteData="@routeData" Selector="h1"/>
     </Found>
     <NotFound>

Iceshrimp.Frontend/Components/Note.razor

@@ -0,0 +1,5 @@
+<h3>Note</h3>
+
+@code {
+    
+}

Iceshrimp.Frontend/Components/RedirectToLogin.razor

@@ -0,0 +1,10 @@
+@* FixMe! Make this actually re-direct back to the content! *@
+@inject NavigationManager Navigation
+<h3>RedirectToLogin</h3>
+@code {
+
+    protected override void OnInitialized()
+    {
+        Navigation.NavigateTo("/login");
+    }
+}

Iceshrimp.Frontend/Core/Schemas/StoredUser.cs

@@ -0,0 +1,9 @@
+using System.Text.Json.Serialization;
+using Iceshrimp.Shared.Schemas;
+
+namespace Iceshrimp.Frontend.Core.Schemas;
+
+public class StoredUser() : UserResponse
+{
+    [JsonPropertyName("token")]              public required string  Token              { get; set; }
+}

Iceshrimp.Frontend/Core/Services/CustomAuthStateProvider.cs

@@ -0,0 +1,22 @@
+using System.Security.Claims;
+
+namespace Iceshrimp.Frontend.Core.Services;
+using Microsoft.AspNetCore.Components.Authorization;
+
+internal class CustomAuthStateProvider (SessionService sessionService) : AuthenticationStateProvider
+{
+    public override Task<AuthenticationState> GetAuthenticationStateAsync()
+    {
+        if (sessionService.Current != null) { 
+          var identity = new ClaimsIdentity(new[] { new Claim(ClaimTypes.Name, sessionService.Current.Username), }, "Custom Authentication");
+          var user = new ClaimsPrincipal(identity);
+          return Task.FromResult(new AuthenticationState(user));
+        }
+        else
+        {
+            var identity = new ClaimsIdentity();
+            var user     = new ClaimsPrincipal(identity);
+            return Task.FromResult(new AuthenticationState(user));
+        }
+    }
+}

Iceshrimp.Frontend/Core/Services/SessionService.cs

@@ -0,0 +1,71 @@
+using Blazored.LocalStorage;
+using Iceshrimp.Frontend.Core.Schemas;
+using Iceshrimp.Shared.Schemas;
+using Microsoft.AspNetCore.Components;
+
+namespace Iceshrimp.Frontend.Core.Services;
+
+internal class SessionService
+{
+    [Inject] public ISyncLocalStorageService       LocalStorage { get; }
+    [Inject] public ApiService                     ApiService   { get; }
+    public          Dictionary<string, StoredUser> Users        { get; }
+    public          UserResponse?                  Current      { get; private set; }
+
+    public SessionService(ApiService apiService, ISyncLocalStorageService localStorage)
+    {
+        ApiService   = apiService;
+        LocalStorage = localStorage;
+        Users        = LocalStorage.GetItem<Dictionary<string, StoredUser>>("Users") ?? [];
+        var lastUser = LocalStorage.GetItem<string?>("last_user");
+        if (lastUser != null)
+        {
+            SetSession(lastUser);
+        }
+    }
+
+    private void WriteUsers()
+    {
+        LocalStorage.SetItem("Users", Users);
+    }
+
+    public void AddUser(StoredUser user)
+    {
+        try
+        {
+            Users.Add(user.Id, user);
+        }
+        catch( ArgumentException ) // Update user if it already exists.
+        {
+            Users[user.Id] = user;
+        }
+        WriteUsers();
+    }
+
+    public void DeleteUser(string id)
+    {
+        if (id == Current?.Id) throw new ArgumentException("Cannot remove current user.");
+        Users.Remove(id);
+        WriteUsers();
+    }
+
+    private StoredUser? GetUserById(string id)
+    {
+        var user = Users[id];
+        return user;
+    }
+
+    public void EndSession()
+    {
+        Current = null;
+        LocalStorage.RemoveItem("last_user");
+    }
+    public void SetSession(string id)
+    {
+        var user = GetUserById(id);
+        if (user == null) throw new Exception("Did not find User in Local Storage");
+        ApiService.SetBearerToken(user.Token);
+        Current = user;
+        LocalStorage.SetItem("last_user", user.Id);
+    }
+}

Iceshrimp.Frontend/Iceshrimp.Frontend.csproj

@@ -23,6 +23,8 @@
     </ItemGroup>
 
     <ItemGroup>
+        <PackageReference Include="Blazored.LocalStorage" Version="4.5.0" />
+        <PackageReference Include="Microsoft.AspNetCore.Components.Authorization" Version="8.0.6" />
         <PackageReference Include="Microsoft.AspNetCore.Components.WebAssembly" Version="8.0.6" />
         <PackageReference Include="Microsoft.AspNetCore.Http.Abstractions" Version="2.2.0"/>
         <PackageReference Include="Microsoft.AspNetCore.SignalR.Client" Version="8.0.6" />

Iceshrimp.Frontend/Pages/Home.razor

@@ -1,4 +1,4 @@
-@page "/"
+@page "/home"
 
 <PageTitle>Home</PageTitle>
 

Iceshrimp.Frontend/Pages/Login.razor

@@ -1,8 +1,72 @@
 @page "/login"
+@using Iceshrimp.Frontend.Core.Miscellaneous
+@using Iceshrimp.Frontend.Core.Schemas
+@using Iceshrimp.Frontend.Core.Services
+@using Iceshrimp.Shared.Schemas
+@inject ApiService     Api
+@inject SessionService        SessionService
+@inject NavigationManager Navigation
 <h3>Login</h3>
+<div>
+    <input
+        @bind="@Username" />
+    <input  
+        @bind="@Password" />
+    <button @onclick="Submit" disabled="@Loading">Login</button>
+</div>
+@if (Loading)
+{
+    <span>Loading!</span>
+}
+@if (Failure)
+{
+    <span>Authentication Failed</span>
+}
 
 <p>A login page is being constructed here.</p>
 
 @code {
-    
+    private string? Password { get; set; }
+    private string? Username { get; set; }
+    private bool    Loading  { get; set; }
+    private bool    Failure  { get; set; }
+
+    private async void Submit()
+    {
+        Loading = true;
+        try
+        {
+            var res = await Api.Auth.Login(new AuthRequest { Username = Username, Password = Password });
+            switch (res.Status)
+            {
+                case AuthStatusEnum.Authenticated:
+                    SessionService.AddUser(new StoredUser
+                    { // Token nor user will ever be null on an authenticated response
+                        Id              = res.User!.Id, 
+                        Username        = res.User.Username,
+                        DisplayName     = res.User.DisplayName,
+                        AvatarUrl       = res.User.AvatarUrl,
+                        BannerUrl       = res.User.BannerUrl,
+                        InstanceName    = res.User.InstanceName,
+                        InstanceIconUrl = res.User.InstanceIconUrl,
+                        Token           = res.Token!
+                    });
+                    SessionService.SetSession(res.User.Id);
+                    Navigation.NavigateTo("/");
+                    break;
+                case AuthStatusEnum.Guest:
+                    Failure = true;
+                    Loading = false;
+                    break;
+                case AuthStatusEnum.TwoFactor:
+                    //FixMe: Implement Two Factor
+                    break;
+            }
+        }
+        catch (ApiException)
+        {
+            Loading = false;
+            Failure = true;
+        }
+    }
 }

Iceshrimp.Frontend/Pages/Timeline.razor

@@ -0,0 +1,39 @@
+@page "/"
+@attribute [Authorize]
+@using Iceshrimp.Frontend.Core.Services
+@using Microsoft.AspNetCore.Authorization
+@using Microsoft.AspNetCore.Components.Authorization
+@inject SessionService Session
+@inject NavigationManager Navigation
+<h3>Timeline</h3>
+@if (username != null)
+{
+    <span>You are logged in as @username </span>
+    <AuthorizeView>
+        <p>Authorization says you are @context.User.Identity!.Name</p>
+    </AuthorizeView>
+    <button @onclick="Logout">Logout</button>
+}else
+{
+    <span>Not logged in</span>
+}
+
+
+
+@code {
+    private string? username;
+
+    protected override void OnInitialized()
+    {
+        if (Session.Current != null)
+        {
+            username = Session.Current.Username;
+        }
+    }
+
+    public void Logout()
+    {
+        Session.EndSession();
+        Navigation.NavigateTo("/login");
+    }
+}

Iceshrimp.Frontend/Startup.cs

@@ -1,7 +1,9 @@
+using Blazored.LocalStorage;
 using Microsoft.AspNetCore.Components.Web;
 using Microsoft.AspNetCore.Components.WebAssembly.Hosting;
 using Iceshrimp.Frontend;
 using Iceshrimp.Frontend.Core.Services;
+using Microsoft.AspNetCore.Components.Authorization;
 
 var builder = WebAssemblyHostBuilder.CreateDefault(args);
 builder.RootComponents.Add<App>("#app");
@@ -10,5 +12,10 @@ builder.RootComponents.Add<HeadOutlet>("head::after");
 builder.Services.AddSingleton(_ => new HttpClient { BaseAddress = new Uri(builder.HostEnvironment.BaseAddress) });
 builder.Services.AddSingleton<ApiClient>();
 builder.Services.AddSingleton<ApiService>();
+builder.Services.AddSingleton<SessionService>();
+builder.Services.AddScoped<AuthenticationStateProvider, CustomAuthStateProvider>();
+builder.Services.AddAuthorizationCore();
+builder.Services.AddCascadingAuthenticationState();
+builder.Services.AddBlazoredLocalStorageAsSingleton();
 
-await builder.Build().RunAsync();
+await builder.Build().RunAsync();