Support Discord game invites in multiplayer lobbies

osu.Desktop/DiscordRichPresence.cs

@@ -5,14 +5,21 @@
 using System.Text;
 using DiscordRPC;
 using DiscordRPC.Message;
+using Newtonsoft.Json;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
+using osu.Framework.Extensions.ObjectExtensions;
 using osu.Framework.Graphics;
 using osu.Framework.Logging;
+using osu.Framework.Threading;
+using osu.Game;
 using osu.Game.Configuration;
 using osu.Game.Extensions;
 using osu.Game.Online.API;
 using osu.Game.Online.API.Requests.Responses;
+using osu.Game.Online.Multiplayer;
+using osu.Game.Online.Rooms;
+using osu.Game.Overlays;
 using osu.Game.Rulesets;
 using osu.Game.Users;
 using LogLevel = osu.Framework.Logging.LogLevel;
@@ -21,7 +28,7 @@ namespace osu.Desktop
 {
     internal partial class DiscordRichPresence : Component
     {
-        private const string client_id = "367827983903490050";
+        private const string client_id = "1216669957799018608";
 
         private DiscordRpcClient client = null!;
 
@@ -33,27 +40,47 @@ internal partial class DiscordRichPresence : Component
         [Resolved]
         private IAPIProvider api { get; set; } = null!;
 
+        [Resolved]
+        private OsuGame game { get; set; } = null!;
+
+        [Resolved]
+        private LoginOverlay? login { get; set; }
+
+        [Resolved]
+        private MultiplayerClient multiplayerClient { get; set; } = null!;
+
         private readonly IBindable<UserStatus?> status = new Bindable<UserStatus?>();
         private readonly IBindable<UserActivity> activity = new Bindable<UserActivity>();
 
         private readonly Bindable<DiscordRichPresenceMode> privacyMode = new Bindable<DiscordRichPresenceMode>();
 
         private readonly RichPresence presence = new RichPresence
         {
-            Assets = new Assets { LargeImageKey = "osu_logo_lazer", }
+            Assets = new Assets { LargeImageKey = "osu_logo_lazer" },
+            Secrets = new Secrets
+            {
+                JoinSecret = null,
+                SpectateSecret = null,
+            },
         };
 
         [BackgroundDependencyLoader]
         private void load(OsuConfigManager config)
         {
             client = new DiscordRpcClient(client_id)
             {
-                SkipIdenticalPresence = false // handles better on discord IPC loss, see updateStatus call in onReady.
+                // SkipIdenticalPresence allows us to fire SetPresence at any point and leave it to the underlying implementation
+                // to check whether a difference has actually occurred before sending a command to Discord (with a minor caveat that's handled in onReady).
+                SkipIdenticalPresence = true
             };
 
             client.OnReady += onReady;
+            client.OnError += (_, e) => Logger.Log($"An error occurred with Discord RPC Client: {e.Code} {e.Message}", LoggingTarget.Network, LogLevel.Error);
 
-            client.OnError += (_, e) => Logger.Log($"An error occurred with Discord RPC Client: {e.Code} {e.Message}", LoggingTarget.Network);
+            // A URI scheme is required to support game invitations, as well as informing Discord of the game executable path to support launching the game when a user clicks on join/spectate.
+            client.RegisterUriScheme();
+            client.Subscribe(EventType.Join);
+            client.OnJoin += onJoin;
 
             config.BindWith(OsuSetting.DiscordRichPresence, privacyMode);
 
@@ -67,35 +94,58 @@ private void load(OsuConfigManager config)
                 activity.BindTo(u.NewValue.Activity);
             }, true);
 
-            ruleset.BindValueChanged(_ => updateStatus());
-            status.BindValueChanged(_ => updateStatus());
-            activity.BindValueChanged(_ => updateStatus());
-            privacyMode.BindValueChanged(_ => updateStatus());
+            ruleset.BindValueChanged(_ => updatePresence());
+            status.BindValueChanged(_ => updatePresence());
+            activity.BindValueChanged(_ => updatePresence());
+            privacyMode.BindValueChanged(_ => updatePresence());
+            multiplayerClient.RoomUpdated += onRoomUpdated;
 
             client.Initialize();
         }
 
         private void onReady(object _, ReadyMessage __)
         {
             Logger.Log("Discord RPC Client ready.", LoggingTarget.Network, LogLevel.Debug);
-            updateStatus();
+
+            // when RPC is lost and reconnected, we have to clear presence state for updatePresence to work (see DiscordRpcClient.SkipIdenticalPresence).
+            if (client.CurrentPresence != null)
+                client.SetPresence(null);
+
+            updatePresence();
         }
 
-        private void updateStatus()
-        {
-            if (!client.IsInitialized)
-                return;
+        private void onRoomUpdated() => updatePresence();
 
-            if (status.Value == UserStatus.Offline || privacyMode.Value == DiscordRichPresenceMode.Off)
-            {
-                client.ClearPresence();
-                return;
-            }
+        private ScheduledDelegate? presenceUpdateDelegate;
 
-            if (activity.Value != null)
+        private void updatePresence()
+        {
+            presenceUpdateDelegate?.Cancel();
+            presenceUpdateDelegate = Scheduler.AddDelayed(() =>
             {
+                if (!client.IsInitialized)
+                    return;
+
+                if (status.Value == UserStatus.Offline || privacyMode.Value == DiscordRichPresenceMode.Off)
+                {
+                    client.ClearPresence();
+                    return;
+                }
+
                 bool hideIdentifiableInformation = privacyMode.Value == DiscordRichPresenceMode.Limited || status.Value == UserStatus.DoNotDisturb;
 
+                updatePresenceStatus(hideIdentifiableInformation);
+                updatePresenceParty(hideIdentifiableInformation);
+                updatePresenceAssets();
+
+                client.SetPresence(presence);
+            }, 200);
+        }
+
+        private void updatePresenceStatus(bool hideIdentifiableInformation)
+        {
+            if (activity.Value != null)
+            {
                 presence.State = truncate(activity.Value.GetStatus(hideIdentifiableInformation));
                 presence.Details = truncate(activity.Value.GetDetails(hideIdentifiableInformation) ?? string.Empty);
 
@@ -120,7 +170,41 @@ private void updateStatus()
                 presence.State = "Idle";
                 presence.Details = string.Empty;
             }
+        }
+
+        private void updatePresenceParty(bool hideIdentifiableInformation)
+        {
+            if (!hideIdentifiableInformation && multiplayerClient.Room != null)
+            {
+                MultiplayerRoom room = multiplayerClient.Room;
+
+                presence.Party = new Party
+                {
+                    Privacy = string.IsNullOrEmpty(room.Settings.Password) ? Party.PrivacySetting.Public : Party.PrivacySetting.Private,
+                    ID = room.RoomID.ToString(),
+                    // technically lobbies can have infinite users, but Discord needs this to be set to something.
+                    // to make party display sensible, assign a powers of two above participants count (8 at minimum).
+                    Max = (int)Math.Max(8, Math.Pow(2, Math.Ceiling(Math.Log2(room.Users.Count)))),
+                    Size = room.Users.Count,
+                };
+
+                RoomSecret roomSecret = new RoomSecret
+                {
+                    RoomID = room.RoomID,
+                    Password = room.Settings.Password,
+                };
+
+                presence.Secrets.JoinSecret = JsonConvert.SerializeObject(roomSecret);
+            }
+            else
+            {
+                presence.Party = null;
+                presence.Secrets.JoinSecret = null;
+            }
+        }
 
+        private void updatePresenceAssets()
+        {
             // update user information
             if (privacyMode.Value == DiscordRichPresenceMode.Limited)
                 presence.Assets.LargeImageText = string.Empty;
@@ -135,13 +219,40 @@ private void updateStatus()
             // update ruleset
             presence.Assets.SmallImageKey = ruleset.Value.IsLegacyRuleset() ? $"mode_{ruleset.Value.OnlineID}" : "mode_custom";
             presence.Assets.SmallImageText = ruleset.Value.Name;
-
-            client.SetPresence(presence);
         }
 
+        private void onJoin(object sender, JoinMessage args) => Scheduler.AddOnce(() =>
+        {
+            game.Window?.Raise();
+
+            if (!api.IsLoggedIn)
+            {
+                login?.Show();
+                return;
+            }
+
+            Logger.Log($"Received room secret from Discord RPC Client: \"{args.Secret}\"", LoggingTarget.Network, LogLevel.Debug);
+
+            // Stable and lazer share the same Discord client ID, meaning they can accept join requests from each other.
+            // Since they aren't compatible in multi, see if stable's format is being used and log to avoid confusion.
+            if (args.Secret[0] != '{' || !tryParseRoomSecret(args.Secret, out long roomId, out string? password))
+            {
+                Logger.Log("Could not join multiplayer room, invitation is invalid or incompatible.", LoggingTarget.Network, LogLevel.Important);
+                return;
+            }
+
+            var request = new GetRoomRequest(roomId);
+            request.Success += room => Schedule(() =>
+            {
+                game.PresentMultiplayerMatch(room, password);
+            });
+            request.Failure += _ => Logger.Log($"Could not join multiplayer room, room could not be found (room ID: {roomId}).", LoggingTarget.Network, LogLevel.Important);
+            api.Queue(request);
+        });
+
         private static readonly int ellipsis_length = Encoding.UTF8.GetByteCount(new[] { '…' });
 
-        private string truncate(string str)
+        private static string truncate(string str)
         {
             if (Encoding.UTF8.GetByteCount(str) <= 128)
                 return str;
@@ -160,7 +271,31 @@ private string truncate(string str)
             });
         }
 
-        private int? getBeatmapID(UserActivity activity)
+        private static bool tryParseRoomSecret(string secretJson, out long roomId, out string? password)
+        {
+            roomId = 0;
+            password = null;
+
+            RoomSecret? roomSecret;
+
+            try
+            {
+                roomSecret = JsonConvert.DeserializeObject<RoomSecret>(secretJson);
+            }
+            catch
+            {
+                return false;
+            }
+
+            if (roomSecret == null) return false;
+
+            roomId = roomSecret.RoomID;
+            password = roomSecret.Password;
+
+            return true;
+        }
+
+        private static int? getBeatmapID(UserActivity activity)
         {
             switch (activity)
             {
@@ -176,8 +311,20 @@ private string truncate(string str)
 
         protected override void Dispose(bool isDisposing)
         {
+            if (multiplayerClient.IsNotNull())
+                multiplayerClient.RoomUpdated -= onRoomUpdated;
+
             client.Dispose();
             base.Dispose(isDisposing);
         }
+
+        private class RoomSecret
+        {
+            [JsonProperty(@"roomId", Required = Required.Always)]
+            public long RoomID { get; set; }
+
+            [JsonProperty(@"password", Required = Required.AllowNull)]
+            public string? Password { get; set; }
+        }
     }
 }