logic in FollowersButton

osu.Game/Overlays/Profile/Header/Components/FollowersButton.cs

@@ -1,10 +1,18 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using System.Linq;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
+using osu.Framework.Extensions.Color4Extensions;
 using osu.Framework.Graphics.Sprites;
+using osu.Framework.Input.Events;
 using osu.Framework.Localisation;
+using osu.Game.Graphics;
+using osu.Game.Online.API;
+using osu.Game.Online.API.Requests;
+using osu.Game.Online.API.Requests.Responses;
+using osu.Game.Overlays.Notifications;
 using osu.Game.Resources.Localisation.Web;
 
 namespace osu.Game.Overlays.Profile.Header.Components
@@ -17,11 +25,158 @@ namespace osu.Game.Overlays.Profile.Header.Components
 
         protected override IconUsage Icon => FontAwesome.Solid.User;
 
+        private readonly IBindableList<APIRelation> apiFriends = new BindableList<APIRelation>();
+        private readonly IBindable<APIUser> localUser = new Bindable<APIUser>();
+
+        private readonly Bindable<FriendStatus> status = new Bindable<FriendStatus>();
+
+        [Resolved]
+        private OsuColour colour { get; set; } = null!;
+
+        [Resolved]
+        private OverlayColourProvider colourProvider { get; set; } = null!;
+
         [BackgroundDependencyLoader]
-        private void load()
+        private void load(IAPIProvider api, INotificationOverlay notifications)
         {
-            // todo: when friending/unfriending is implemented, the APIAccess.Friends list should be updated accordingly.
-            User.BindValueChanged(user => SetValue(user.NewValue?.User.FollowerCount ?? 0), true);
+            localUser.BindTo(api.LocalUser);
+
+            status.BindValueChanged(_ =>
+            {
+                updateIcon();
+                updateColor();
+            });
+
+            User.BindValueChanged(_ => updateStatus(), true);
+
+            apiFriends.BindTo(api.Friends);
+            apiFriends.BindCollectionChanged((_, _) => Schedule(updateStatus));
+
+            Action += () =>
+            {
+                if (User.Value == null)
+                    return;
+
+                if (status.Value == FriendStatus.Self)
+                    return;
+
+                ShowLodingLayer();
+
+                APIRequest req = status.Value == FriendStatus.None ? new FriendAddRequest(User.Value.User.OnlineID) : new FriendDeleteRequest(User.Value.User.OnlineID);
+
+                req.Success += () =>
+                {
+                    api.UpdateLocalFriends();
+                    HideLodingLayer();
+                };
+
+                req.Failure += e =>
+                {
+                    notifications?.Post(new SimpleNotification
+                    {
+                        Text = e.Message,
+                        Icon = FontAwesome.Solid.Times,
+                    });
+
+                    HideLodingLayer();
+                };
+
+                api.Queue(req);
+            };
+        }
+
+        protected override bool OnHover(HoverEvent e)
+        {
+            if (status.Value > FriendStatus.None)
+            {
+                SetIcon(FontAwesome.Solid.UserTimes);
+            }
+
+            return base.OnHover(e);
+        }
+
+        protected override void OnHoverLost(HoverLostEvent e)
+        {
+            base.OnHoverLost(e);
+
+            updateIcon();
+        }
+
+        private void updateStatus()
+        {
+            SetValue(User.Value?.User.FollowerCount ?? 0);
+
+            if (localUser.Value.OnlineID == User.Value?.User.OnlineID)
+            {
+                status.Value = FriendStatus.Self;
+                return;
+            }
+
+            var friend = apiFriends.FirstOrDefault(u => User.Value?.User.OnlineID == u.TargetID);
+
+            if (friend != null)
+            {
+                status.Value = friend.Mutual ? FriendStatus.Mutual : FriendStatus.NotMutual;
+            }
+            else
+            {
+                status.Value = FriendStatus.None;
+            }
+        }
+
+        private void updateIcon()
+        {
+            switch (status.Value)
+            {
+                case FriendStatus.Self:
+                    SetIcon(FontAwesome.Solid.User);
+                    break;
+
+                case FriendStatus.None:
+                    SetIcon(FontAwesome.Solid.UserPlus);
+                    break;
+
+                case FriendStatus.NotMutual:
+                    SetIcon(FontAwesome.Solid.User);
+                    break;
+
+                case FriendStatus.Mutual:
+                    SetIcon(FontAwesome.Solid.UserFriends);
+                    break;
+            }
+        }
+
+        private void updateColor()
+        {
+            switch (status.Value)
+            {
+                case FriendStatus.Self:
+                case FriendStatus.None:
+                    IdleColour = colourProvider.Background6;
+                    HoverColour = colourProvider.Background5;
+                    SetBackGroundColour(colourProvider.Background6, 200);
+                    break;
+
+                case FriendStatus.NotMutual:
+                    IdleColour = colour.Green;
+                    HoverColour = colour.Green.Lighten(0.1f);
+                    SetBackGroundColour(colour.Green, 200);
+                    break;
+
+                case FriendStatus.Mutual:
+                    IdleColour = colour.Pink;
+                    HoverColour = colour.Pink1.Lighten(0.1f);
+                    SetBackGroundColour(colour.Pink, 200);
+                    break;
+            }
+        }
+
+        private enum FriendStatus
+        {
+            Self,
+            None,
+            NotMutual,
+            Mutual,
         }
     }
 }