State transitions for presence event engine (#203)

Co-authored-by: Mohit Tejani <[email protected]>
Co-authored-by: Mohit Tejani <[email protected]>

.github/workflows/run-tests.yml

@@ -29,8 +29,7 @@ jobs:
       - name: Setup .NET
         uses: actions/setup-dotnet@v3
         with:
-          dotnet-version: | 
-            2.1.519
+          dotnet-version: |
             5.0.x
             6.0.x
       - name: Build packages

src/Api/PubnubApi/EventEngine/Presence/Common/PresenceInput.cs

@@ -0,0 +1,36 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace PubnubApi.EventEngine.Presence.Common
+{
+    public class PresenceInput
+    {
+        public IEnumerable<string> Channels { get; set; }
+        public IEnumerable<string> ChannelGroups { get; set; }
+
+        public static PresenceInput operator +(PresenceInput a, PresenceInput b)
+        {
+            return new PresenceInput
+            {
+                Channels = a.Channels?.Union(b.Channels ?? new string[0]),
+                ChannelGroups = a.ChannelGroups?.Union(b.ChannelGroups ?? new string[0]),
+            };
+        }
+
+        public static PresenceInput operator -(PresenceInput a, PresenceInput b)
+        {
+            return new PresenceInput
+            {
+                Channels = a.Channels?.Except(b.Channels ?? new string[0]),
+                ChannelGroups = a.ChannelGroups?.Except(b.ChannelGroups ?? new string[0]),
+            };
+        }
+
+        public bool IsEmpty()
+        {
+            return (Channels == null && ChannelGroups == null)
+                || ((Channels != null && Channels.Count() == 0)
+                        && (ChannelGroups != null && ChannelGroups.Count() == 0));
+        }
+    }
+}

src/Api/PubnubApi/EventEngine/Presence/Events/PresenceEvents.cs

@@ -0,0 +1,35 @@
+using System.Collections.Generic;
+using PubnubApi;
+using PubnubApi.EventEngine.Presence.Common;
+
+namespace PubnubApi.EventEngine.Presence.Events {
+    public class JoinedEvent : Core.IEvent 
+    {
+        public PresenceInput Input { get; set; }
+    }
+
+    public class LeftEvent : Core.IEvent 
+    {
+        public PresenceInput Input { get; set; }
+    }
+
+    public class LeftAllEvent : Core.IEvent {}
+
+    public class HeartbeatSuccessEvent : Core.IEvent {}
+
+    public class HeartbeatFailureEvent : Core.IEvent 
+    {
+        public PNStatus Status { get; set; }
+    }
+
+    public class HeartbeatGiveUpEvent : Core.IEvent 
+    {
+        public PNStatus Status { get; set; }
+    }
+
+    public class ReconnectEvent : Core.IEvent {}
+
+    public class DisconnectEvent : Core.IEvent {}
+
+    public class TimesUpEvent : Core.IEvent {}
+}

src/Api/PubnubApi/EventEngine/Presence/Invocations/Dummy.cs

@@ -0,0 +1,4 @@
+// TODO: Dummy Invocation until we have real ones
+namespace PubnubApi.EventEngine.Presence.Invocations {
+    public class DummyInvocation : Core.IEffectInvocation {}
+}

src/Api/PubnubApi/EventEngine/Presence/States/APresenceState.cs

@@ -0,0 +1,27 @@
+using PubnubApi.EventEngine.Core;
+using PubnubApi.EventEngine.Presence.Common;
+
+namespace PubnubApi.EventEngine.Presence.States
+{
+    public abstract class APresenceState : Core.State
+    {
+        public PresenceInput Input { get; set; }
+
+        public bool IsEmpty()
+        {
+            return Input.IsEmpty();
+        }
+
+        protected TransitionResult HandleLeftEvent(Events.LeftEvent e) 
+        {
+            var newInput = this.Input - e.Input;
+
+            return newInput.IsEmpty()
+                ? (TransitionResult)new InactiveState()
+                : (TransitionResult)new HeartbeatingState()
+                {
+                    Input = newInput,
+                };
+        }
+    }
+}

src/Api/PubnubApi/EventEngine/Presence/States/CooldownState.cs

@@ -0,0 +1,38 @@
+using PubnubApi;
+using PubnubApi.EventEngine.Presence.Invocations;
+using PubnubApi.EventEngine.Core;
+using System.Collections.Generic;
+using System;
+
+namespace PubnubApi.EventEngine.Presence.States
+{
+    public class CooldownState : APresenceState
+    {
+        // TODO: Dummy Invocation until we have real ones
+        public override IEnumerable<IEffectInvocation> OnEntry => new DummyInvocation().AsArray();
+        public override IEnumerable<IEffectInvocation> OnExit => new DummyInvocation().AsArray();
+
+        // TODO: transitions
+        public override TransitionResult Transition(IEvent ev)
+        {
+            return ev switch 
+            {
+                Events.JoinedEvent e => new HeartbeatingState()
+                {
+                    Input = e.Input != this.Input ? this.Input + e.Input : this.Input,
+                },
+                Events.LeftEvent e => HandleLeftEvent(e),
+                Events.LeftAllEvent e => new InactiveState(),
+                Events.DisconnectEvent e => new StoppedState()
+                {
+                    Input = this.Input,
+                },
+                Events.TimesUpEvent e => new HeartbeatingState()
+                {
+                    Input = this.Input,
+                },
+                _ => null,
+            };
+        }
+    }
+}

src/Api/PubnubApi/EventEngine/Presence/States/FailedState.cs

@@ -0,0 +1,40 @@
+using PubnubApi.EventEngine.Presence.Invocations;
+using PubnubApi.EventEngine.Core;
+using System.Collections.Generic;
+using System;
+
+namespace PubnubApi.EventEngine.Presence.States
+{
+    public class FailedState : APresenceState
+    {
+        public PNStatus Reason { get; set; }
+
+        // TODO: Dummy Invocation until we have real ones
+        public override IEnumerable<IEffectInvocation> OnEntry => new DummyInvocation().AsArray();
+        public override IEnumerable<IEffectInvocation> OnExit => new DummyInvocation().AsArray();
+
+        // TODO: transitions
+        public override TransitionResult Transition(IEvent ev)
+        {
+            return ev switch 
+            {
+                Events.JoinedEvent e => new HeartbeatingState()
+                {
+                    Input = e.Input != this.Input ? this.Input + e.Input : this.Input,
+                },
+                Events.LeftEvent e => HandleLeftEvent(e),
+                Events.LeftAllEvent e => new InactiveState(),
+                Events.ReconnectEvent e => new HeartbeatingState()
+                {
+                    Input = this.Input,
+                },
+                Events.DisconnectEvent e => new StoppedState()
+                {
+                    Input = this.Input,
+                }, 
+                _ => null,
+            };
+        }
+    }
+
+}

src/Api/PubnubApi/EventEngine/Presence/States/HeartBeatingState.cs

@@ -0,0 +1,51 @@
+using PubnubApi.EventEngine.Presence.Invocations;
+using PubnubApi.EventEngine.Core;
+using System.Collections.Generic;
+using System;
+
+namespace PubnubApi.EventEngine.Presence.States
+{
+    public class HeartbeatingState : APresenceState
+    {
+        // TODO: Dummy Invocation until we have real ones
+        public override IEnumerable<IEffectInvocation> OnEntry => new DummyInvocation().AsArray();
+        public override IEnumerable<IEffectInvocation> OnExit => new DummyInvocation().AsArray();
+
+        // TODO: transitions
+        public override TransitionResult Transition(IEvent ev)
+        {
+            return ev switch 
+            {
+                Events.JoinedEvent e => new HeartbeatingState()
+                {
+                    Input = e.Input != this.Input ? this.Input + e.Input : this.Input,
+                },
+                Events.LeftEvent e => HandleLeftEvent(e),
+                Events.LeftAllEvent e => new InactiveState(),
+                Events.HeartbeatSuccessEvent e => new CooldownState()
+                {
+                    Input = this.Input,
+                },
+                Events.HeartbeatFailureEvent e => HandleHeartbeatFailureEvent(e), 
+                Events.DisconnectEvent e => new StoppedState()
+                {
+                    Input = this.Input,
+                }, 
+                _ => null,
+            };
+        }
+
+        private TransitionResult HandleHeartbeatFailureEvent(Events.HeartbeatFailureEvent e)
+        {
+            return e.Status.Category == PNStatusCategory.PNCancelledCategory
+                ? (TransitionResult)null 
+                : (TransitionResult)new ReconnectingState()
+                {
+                    Input = this.Input,
+                    RetryCount = 1,
+                    Reason = e.Status,
+                };                
+        }
+    }
+
+}

src/Api/PubnubApi/EventEngine/Presence/States/InactiveState.cs

@@ -0,0 +1,33 @@
+using PubnubApi.EventEngine.Presence.Invocations;
+using PubnubApi.EventEngine.Core;
+using System.Collections.Generic;
+using System;
+
+namespace PubnubApi.EventEngine.Presence.States
+{
+    public class InactiveState : APresenceState
+    {
+        public InactiveState()
+        {
+            Input = null;
+        }
+
+        // TODO: Dummy Invocation until we have real ones
+        public override IEnumerable<IEffectInvocation> OnEntry => new DummyInvocation().AsArray();
+        public override IEnumerable<IEffectInvocation> OnExit => new DummyInvocation().AsArray();
+
+        // TODO: transitions
+        public override TransitionResult Transition(IEvent ev)
+        {
+            return ev switch 
+            {
+                Events.JoinedEvent e => new HeartbeatingState()
+                {
+                    Input = e.Input,
+                },
+                _ => null,
+            };
+        }
+    }
+
+}

src/Api/PubnubApi/EventEngine/Presence/States/ReconnectingState.cs

@@ -0,0 +1,59 @@
+using PubnubApi.EventEngine.Presence.Invocations;
+using PubnubApi.EventEngine.Core;
+using System.Collections.Generic;
+using System;
+
+namespace PubnubApi.EventEngine.Presence.States
+{
+    public class ReconnectingState : APresenceState
+    {
+        public int RetryCount { get; set; }
+        public PNStatus Reason { get; set; }
+
+        // TODO: Dummy Invocation until we have real ones
+        public override IEnumerable<IEffectInvocation> OnEntry => new DummyInvocation().AsArray();
+        public override IEnumerable<IEffectInvocation> OnExit => new DummyInvocation().AsArray();
+
+        // TODO: transitions
+        public override TransitionResult Transition(IEvent ev)
+        {
+            return ev switch 
+            {
+                Events.JoinedEvent e => new HeartbeatingState()
+                {
+                    Input = e.Input != this.Input ? this.Input + e.Input : this.Input,
+                },
+                Events.LeftEvent e => HandleLeftEvent(e),
+                Events.LeftAllEvent e => new InactiveState(),
+                Events.HeartbeatSuccessEvent e => new CooldownState()
+                {
+                    Input = this.Input,
+                },
+                Events.HeartbeatFailureEvent e => HandleHeartbeatFailureEvent(e),
+                Events.HeartbeatGiveUpEvent e => new FailedState()
+                {
+                    Input = this.Input,
+                    Reason = this.Reason,
+                },
+                Events.DisconnectEvent e => new StoppedState()
+                {
+                    Input = this.Input,
+                }, 
+                _ => null,
+            };
+        }
+
+        private TransitionResult HandleHeartbeatFailureEvent(Events.HeartbeatFailureEvent e)
+        {
+            return e.Status.Category == PNStatusCategory.PNCancelledCategory
+                ? (TransitionResult)null 
+                : (TransitionResult)new ReconnectingState()
+                {
+                    Input = this.Input,
+                    RetryCount = this.RetryCount + 1,
+                    Reason = e.Status,
+                };                
+        }
+    }
+
+}

src/Api/PubnubApi/EventEngine/Presence/States/StoppedState.cs

@@ -0,0 +1,46 @@
+using PubnubApi.EventEngine.Presence.Invocations;
+using PubnubApi.EventEngine.Core;
+using System.Collections.Generic;
+using System;
+
+namespace PubnubApi.EventEngine.Presence.States
+{
+    public class StoppedState : APresenceState
+    {
+        // TODO: Dummy Invocation until we have real ones
+        public override IEnumerable<IEffectInvocation> OnEntry => new DummyInvocation().AsArray();
+        public override IEnumerable<IEffectInvocation> OnExit => new DummyInvocation().AsArray();
+
+        // TODO: transitions
+        public override TransitionResult Transition(IEvent ev)
+        {
+            return ev switch 
+            {
+                Events.JoinedEvent e => new StoppedState()
+                {
+                    Input = e.Input != this.Input ? this.Input + e.Input : this.Input,
+                },
+                Events.LeftEvent e => HandleLeftEvent(e),
+                Events.LeftAllEvent e => new InactiveState(),
+                Events.ReconnectEvent e => new HeartbeatingState()
+                {
+                    Input = this.Input,
+                },
+                 _ => null,
+            };
+        }
+
+        protected TransitionResult HandleLeftEvent(Events.LeftEvent e)
+        {
+            var newInput = this.Input - e.Input;
+
+            return newInput.IsEmpty()
+                ? (TransitionResult)new InactiveState()
+                : (TransitionResult)new StoppedState()
+                {
+                    Input = newInput,
+                };
+        }
+    }
+
+}

src/Api/PubnubApi/EventEngine/Subscribe/Effects/EmitStatusEffectHandler.cs

@@ -25,4 +25,4 @@ public override async Task Run(EmitStatusInvocation invocation)
 			this.statusEmitterFunction(this.pubnubInstance, invocation.Status);
 		}
 	}
-}
+}