Lazy deserialization of StateChanges (#1146)

Author: FrankBakkerNl

src/HassModel/NetDaemon.HassModel.Tests/Internal/EntityStateCacheTest.cs

@@ -4,6 +4,7 @@
 using NetDaemon.Client.Internal.HomeAssistant.Commands;
 using NetDaemon.HassModel.Tests.TestHelpers;
 using Microsoft.Extensions.DependencyInjection;
+using NetDaemon.Client.Internal.Extensions;
 using NetDaemon.HassModel.Internal;
 
 namespace NetDaemon.HassModel.Tests.Internal;
@@ -17,36 +18,26 @@ public async Task StateChangeEventIsFirstStoredInCacheThanForwarded()
 
         // Arrange
         using var testSubject = new Subject<HassEvent>();
-        var _hassConnectionMock = new Mock<IHomeAssistantConnection>();
+        var hassConnectionMock = new Mock<IHomeAssistantConnection>();
         var haRunnerMock = new Mock<IHomeAssistantRunner>();
 
-        haRunnerMock.SetupGet(n => n.CurrentConnection).Returns(_hassConnectionMock.Object);
+        haRunnerMock.SetupGet(n => n.CurrentConnection).Returns(hassConnectionMock.Object);
 
-        _hassConnectionMock.Setup(
-                m => m.SendCommandAndReturnResponseAsync<SimpleCommand, IReadOnlyCollection<HassState>>
-                (
-                    It.IsAny<SimpleCommand>(), It.IsAny<CancellationToken>()
-                ))
-            .ReturnsAsync(new List<HassState>
-            {
-                new() {EntityId = entityId, State = "InitialState"}
-            });
-
-        _hassConnectionMock.Setup(n =>
-                n.SubscribeToHomeAssistantEventsAsync(It.IsAny<string>(), It.IsAny<CancellationToken>()))
-            .ReturnsAsync(testSubject
-            );
+        hassConnectionMock
+            .Setup(m => m.SendCommandAndReturnResponseAsync<SimpleCommand, IReadOnlyCollection<HassState>>
+                    (It.IsAny<SimpleCommand>(), It.IsAny<CancellationToken>()))
+            .ReturnsAsync([new HassState {EntityId = entityId, State = "InitialState"}]);
 
-        var serviceColletion = new ServiceCollection();
-        _ = serviceColletion.AddTransient<IObservable<HassEvent>>(_ => testSubject);
-        var sp = serviceColletion.BuildServiceProvider();
+        hassConnectionMock
+            .Setup(n => n.SubscribeToHomeAssistantEventsAsync(It.IsAny<string>(), It.IsAny<CancellationToken>()))
+            .ReturnsAsync(testSubject);
 
-        using var cache = new EntityStateCache(haRunnerMock.Object, sp);
+        using var cache = new EntityStateCache(haRunnerMock.Object);
 
         var eventObserverMock = new Mock<IObserver<HassEvent>>();
         cache.AllEvents.Subscribe(eventObserverMock.Object);
 
-        // ACT 1: after initialization of the cache it should show the values retieved from Hass
+        // ACT 1: after initialization of the cache it should show the values retrieved from Hass
         await cache.InitializeAsync(CancellationToken.None);
 
         cache.GetState(entityId)!.State.Should().Be("InitialState", "The initial value should be available");
@@ -66,7 +57,7 @@ public async Task StateChangeEventIsFirstStoredInCacheThanForwarded()
             .Callback(() =>
             {
 #pragma warning disable 8602
-                cache.GetState(entityId).State.Should().Be("newState");
+                cache.GetState(entityId).State.Should().Be("newState", because: "The cache should already have the new value when the event handler runs");
 #pragma warning restore 8602
             });
 
@@ -87,57 +78,70 @@ public async Task AllEntityIds_returnsInitialPlusChangedEntities()
     {
         // Arrange
         using var testSubject = new Subject<HassEvent>();
-        var _hassConnectionMock = new Mock<IHomeAssistantConnection>();
+        var hassConnectionMock = new Mock<IHomeAssistantConnection>();
         var haRunnerMock = new Mock<IHomeAssistantRunner>();
 
-        haRunnerMock.SetupGet(n => n.CurrentConnection).Returns(_hassConnectionMock.Object);
-
-        _hassConnectionMock.Setup(
-                m => m.SendCommandAndReturnResponseAsync<SimpleCommand, IReadOnlyCollection<HassState>>
-                (
-                    It.IsAny<SimpleCommand>(), It.IsAny<CancellationToken>()
-                ))
-            .ReturnsAsync(new List<HassState>
-            {
-                new() {EntityId = "sensor.sensor1", State = "InitialState"}
-            });
+        haRunnerMock.SetupGet(n => n.CurrentConnection).Returns(hassConnectionMock.Object);
 
-        var serviceColletion = new ServiceCollection();
+        hassConnectionMock
+            .Setup(m => m.SendCommandAndReturnResponseAsync<SimpleCommand, IReadOnlyCollection<HassState>>
+                (It.IsAny<SimpleCommand>(), It.IsAny<CancellationToken>()))
+            .ReturnsAsync([new()
+                {
+                    EntityId = "sensor.sensor1",
+                    State = "InitialState",
+                    AttributesJson = new { brightness = 100 }.ToJsonElement(),
+                }]);
 
-        _hassConnectionMock.Setup(n =>
+        hassConnectionMock.Setup(n =>
                 n.SubscribeToHomeAssistantEventsAsync(It.IsAny<string>(), It.IsAny<CancellationToken>()))
-            .ReturnsAsync(testSubject
-            );
-
-        var sp = serviceColletion.BuildServiceProvider();
+            .ReturnsAsync(testSubject);
 
-        using var cache = new EntityStateCache(haRunnerMock.Object, sp);
+        using var cache = new EntityStateCache(haRunnerMock.Object);
 
         var stateChangeObserverMock = new Mock<IObserver<HassEvent>>();
         cache.AllEvents.Subscribe(stateChangeObserverMock.Object);
 
         // ACT 1: after initialization of the cache it should show the values retieved from Hass
         await cache.InitializeAsync(CancellationToken.None);
 
-        // Act 2: now fire a state change event
-        var changedEventData = new HassStateChangedEventData
+        // initial value for sensor.sensor1 shoul be visible right away
+        cache.GetState("sensor.sensor1")!.AttributesJson.GetValueOrDefault().GetProperty("brightness").GetInt32().Should().Be(100);
+
+        // Act 2: now fire 2 state change events
+        testSubject.OnNext(new HassEvent
         {
-            EntityId = "sensor.sensor2",
-            OldState = new HassState(),
-            NewState = new HassState
+            EventType = "state_changed",
+            DataElement = new HassStateChangedEventData
             {
-                State = "newState"
-            }
-        };
+                EntityId = "sensor.sensor1",
+                OldState = new HassState(),
+                NewState = new HassState
+                {
+                    State = "newState",
+                    AttributesJson = new {brightness = 200}.ToJsonElement()
+                }
+            }.AsJsonElement()
+        });
 
-        // Act
         testSubject.OnNext(new HassEvent
         {
             EventType = "state_changed",
-            DataElement = changedEventData.AsJsonElement()
+            DataElement = new HassStateChangedEventData
+            {
+                EntityId = "sensor.sensor2",
+                OldState = new HassState(),
+                NewState = new HassState
+                {
+                    State = "newState",
+                    AttributesJson = new {brightness = 300}.ToJsonElement()
+                }
+            }.AsJsonElement()
         });
 
         // Assert
         cache.AllEntityIds.Should().BeEquivalentTo("sensor.sensor1", "sensor.sensor2");
+        cache.GetState("sensor.sensor1")!.AttributesJson.GetValueOrDefault().GetProperty("brightness").GetInt32().Should().Be(200);
+        cache.GetState("sensor.sensor2")!.AttributesJson.GetValueOrDefault().GetProperty("brightness").GetInt32().Should().Be(300);
     }
 }

src/HassModel/NetDeamon.HassModel/Entities/EntityState.cs

@@ -6,37 +6,38 @@
 public record EntityState
 {
     /// <summary>Unique id of the entity</summary>
-    public string EntityId { get; init; } = "";
-    
+    [JsonPropertyName("entity_id")] public string EntityId { get; init; } = "";
+
     /// <summary>The state </summary>
-    public string? State { get; init; }
+    [JsonPropertyName("state")] public string? State { get; init; }
 
     /// <summary>The attributes as a JsonElement</summary>
-    public JsonElement? AttributesJson { get; init; }
-        
+    [JsonPropertyName("attributes")] public JsonElement? AttributesJson { get; init; }
+
     /// <summary>
     /// The attributes
     /// </summary>
     public virtual object? Attributes => AttributesJson?.Deserialize<Dictionary<string, object>>() ?? new Dictionary<string, object>();
-    
+
     /// <summary>Last changed, when state changed from and to different values</summary>
-    public DateTime? LastChanged { get; init; }
-    
+    [JsonPropertyName("last_changed")] public DateTime? LastChanged { get; init; }
+
     /// <summary>Last updated, when entity state or attributes changed </summary>
-    public DateTime? LastUpdated { get; init; }
-    
+    [JsonPropertyName("last_updated")] public DateTime? LastUpdated { get; init; }
+
     /// <summary>Context</summary>
-    public Context? Context { get; init; }
-        
+    [JsonPropertyName("context")] public Context? Context { get; init; }
+
     internal static TEntityState? Map<TEntityState>(EntityState? state)
-        where TEntityState : class => 
-        state == null ? null : (TEntityState)Activator.CreateInstance(typeof(TEntityState), state)!;    }
-    
+        where TEntityState : class =>
+        state == null ? null : (TEntityState)Activator.CreateInstance(typeof(TEntityState), state)!;
+}
+
 /// <summary>
 /// Generic EntityState with specific types of State and Attributes
 /// </summary>
 /// <typeparam name="TAttributes">The type of the Attributes Property</typeparam>
-public record EntityState<TAttributes> : EntityState 
+public record EntityState<TAttributes> : EntityState
     where TAttributes : class
 {
     private readonly Lazy<TAttributes?> _attributesLazy;
@@ -47,7 +48,7 @@ public record EntityState<TAttributes> : EntityState
     /// <param name="source"></param>
     public EntityState(EntityState source) : base(source)
     {
-        _attributesLazy = new (() => AttributesJson?.Deserialize<TAttributes>() ?? default);            
+        _attributesLazy = new (() => AttributesJson?.Deserialize<TAttributes>() ?? default);
     }
 
     /// <inheritdoc/>

src/HassModel/NetDeamon.HassModel/Entities/StateChange.cs

@@ -5,6 +5,23 @@
 /// </summary>
 public record StateChange
 {
+    private readonly JsonElement _jsonElement;
+    private readonly IHaContext _haContext;
+    private Entity? _entity;
+    private EntityState? _old;
+    private EntityState? _new;
+
+    /// <summary>
+    /// Creates a StateChange from a jsonElement and lazy load the states
+    /// </summary>
+    /// <param name="jsonElement"></param>
+    /// <param name="haContext"></param>
+    internal StateChange(JsonElement jsonElement, IHaContext haContext)
+    {
+        _jsonElement = jsonElement;
+        _haContext = haContext;
+    }
+
     /// <summary>
     /// This should not be used under normal circumstances but can be used for unit testing of apps
     /// </summary>
@@ -13,23 +30,24 @@ public record StateChange
     /// <param name="new"></param>
     public StateChange(Entity entity, EntityState? old, EntityState? @new)
     {
-        Entity = entity;
-        New    = @new;
-        Old    = old;
+        _entity = entity;
+        _new    = @new;
+        _old    = old;
+        _haContext = null!; // haContext is not used when _entity is already initialized
     }
 
     /// <summary>The Entity that changed</summary>
-    public virtual Entity Entity { get; } = default!; // Somehow this is needed to avoid a warning about this field being initialized
+    public virtual Entity Entity => _entity ??= new Entity(_haContext, _jsonElement.GetProperty("entity_id").GetString() ?? throw  new InvalidOperationException("No Entity_id in state_change event"));
 
     /// <summary>The old state of the entity</summary>
-    public virtual EntityState? Old { get; }
+    public virtual EntityState? Old => _old ??= _jsonElement.GetProperty("old_state").Deserialize<EntityState>();
 
     /// <summary>The new state of the entity</summary>
-    public virtual EntityState? New { get; }
+    public virtual EntityState? New => _new ??= _jsonElement.GetProperty("new_state").Deserialize<EntityState>();
 }
 
 /// <summary>
-/// Represents a state change event for a strong typed entity and state 
+/// Represents a state change event for a strong typed entity and state
 /// </summary>
 /// <typeparam name="TEntity">The Type</typeparam>
 /// <typeparam name="TEntityState"></typeparam>
@@ -55,4 +73,4 @@ public StateChange(TEntity entity, TEntityState? old, TEntityState? @new) : base
 
     /// <inheritdoc/>
     public override TEntityState? Old => (TEntityState?)base.Old;
-}
+}

src/HassModel/NetDeamon.HassModel/Internal/AppScopedHaContextProvider.cs

@@ -49,7 +49,7 @@ public AppScopedHaContextProvider(
 
     public EntityState? GetState(string entityId)
     {
-        return _entityStateCache.GetState(entityId).Map();
+        return _entityStateCache.GetState(entityId);
     }
 
     [Obsolete("Use Registry to navigate Entities, Devices and Areas")]
@@ -86,10 +86,9 @@ public void CallService(string domain, string service, ServiceTarget? target = n
 
     public IObservable<StateChange> StateAllChanges()
     {
-        return _queuedObservable.Where(n =>
-            n.EventType == "state_changed")
-            .Select(n => n.ToStateChangedEvent()!)
-            .Select(e => e.Map(this));
+        return _queuedObservable
+            .Where(n => n.EventType == "state_changed")
+            .Select(n => new StateChange(n.DataElement.GetValueOrDefault(), this));
     }
 
     public IObservable<Event> Events => _queuedObservable