Add basic login flow.

osu.Game/Online/API/APIAccess.cs

@@ -4,6 +4,7 @@
 using System;
 using System.Collections.Concurrent;
 using System.Collections.Generic;
+using System.Diagnostics;
 using System.Net;
 using System.Threading;
 using osu.Framework;
@@ -71,6 +72,7 @@ namespace osu.Game.Online.API
         public void Register(IOnlineComponent component)
         {
             components.Add(component);
+            component.APIStateChanged(this, state);
         }
 
         public void Unregister(IOnlineComponent component)
@@ -158,6 +160,16 @@ namespace osu.Game.Online.API
             password = null;
         }
 
+        public void Login(string username, string password)
+        {
+            Debug.Assert(State == APIState.Offline);
+
+            Username = username;
+            Password = password;
+
+            State = APIState.Connecting;
+        }
+
         /// <summary>
         /// Handle a single API request.
         /// </summary>
@@ -167,6 +179,7 @@ namespace osu.Game.Online.API
         {
             try
             {
+                Logger.Log($@"Performing request {req}", LoggingTarget.Network);
                 req.Perform(this);
 
                 State = APIState.Online;

osu.Game/Overlays/Options/General/LoginOptions.cs

@@ -1,4 +1,5 @@
-using OpenTK;
+using System;
+using OpenTK;
 using osu.Framework;
 using osu.Framework.Allocation;
 using osu.Framework.Graphics;
@@ -10,7 +11,7 @@ using osu.Game.Online.API;
 
 namespace osu.Game.Overlays.Options.General
 {
-    public class LoginOptions : OptionsSubsection
+    public class LoginOptions : OptionsSubsection, IOnlineComponent
     {
         private Container loginForm;
         protected override string Header => "Sign In";
@@ -31,16 +32,56 @@ namespace osu.Game.Overlays.Options.General
         [BackgroundDependencyLoader(permitNulls: true)]
         private void load(APIAccess api)
         {
-            if (api == null)
+            api?.Register(this);
-                return;
+        }
-            loginForm.Children = new Drawable[]
+
+        public void APIStateChanged(APIAccess api, APIState state)
+        {
+            switch (state)
             {
-                new LoginForm(api)
+                case APIState.Offline:
-            };
+                    loginForm.Children = new Drawable[]
+                    {
+                        new LoginForm(api)
+                    };
+                    break;
+                case APIState.Failing:
+                    loginForm.Children = new Drawable[]
+                    {
+                        new SpriteText
+                        {
+                            Text = @"Connection failing :(",
+                        },
+                    };
+                    break;
+                case APIState.Connecting:
+                    loginForm.Children = new Drawable[]
+                    {
+                        new SpriteText
+                        {
+                            Text = @"Connecting...",
+                        },
+                    };
+                    break;
+                case APIState.Online:
+                    loginForm.Children = new Drawable[]
+                    {
+                        new SpriteText
+                        {
+                            Text = $@"Connected as {api.Username}!",
+                        },
+                    };
+                    break;
+            }
         }
 
         class LoginForm : FlowContainer
         {
+            private APIAccess api;
+
+            private TextBox username;
+            private TextBox password;
+
             public LoginForm(APIAccess api)
             {
                 Direction = FlowDirection.VerticalOnly;
@@ -51,16 +92,28 @@ namespace osu.Game.Overlays.Options.General
                 Children = new Drawable[]
                 {
                     new SpriteText { Text = "Username" },
-                    new TextBox { Height = 20, RelativeSizeAxes = Axes.X, Text = api?.Username ?? string.Empty },
+                    username = new TextBox { Height = 20, RelativeSizeAxes = Axes.X, Text = api?.Username ?? string.Empty },
                     new SpriteText { Text = "Password" },
-                    new TextBox { Height = 20, RelativeSizeAxes = Axes.X },
+                    password = new PasswordTextBox { Height = 20, RelativeSizeAxes = Axes.X },
                     new OsuButton
                     {
                         RelativeSizeAxes = Axes.X,
                         Text = "Log in",
+                        Action = performLogin
                     }
                 };
             }
+
+            private void performLogin()
+            {
+                api.Login(username.Text, password.Text);
+            }
+
+            [BackgroundDependencyLoader(permitNulls: true)]
+            private void load(APIAccess api)
+            {
+                this.api = api;
+            }
         }
     }
 }