Add focused changed lifecycle event

Dalamud/Game/Addon/Lifecycle/AddonArgTypes/AddonFocusChangedArgs.cs

@@ -0,0 +1,22 @@
+namespace Dalamud.Game.Addon.Lifecycle.AddonArgTypes;
+
+/// <summary>
+/// Addon argument data for OnFocusChanged events.
+/// </summary>
+public class AddonFocusChangedArgs : AddonArgs
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="AddonFocusChangedArgs"/> class.
+    /// </summary>
+    internal AddonFocusChangedArgs()
+    {
+    }
+
+    /// <inheritdoc/>
+    public override AddonArgsType Type => AddonArgsType.FocusChanged;
+
+    /// <summary>
+    /// Gets or sets a value indicating whether the window is being focused or unfocused.
+    /// </summary>
+    public bool ShouldFocus { get; set; }
+}

Dalamud/Game/Addon/Lifecycle/AddonArgsType.cs

@@ -44,4 +44,9 @@ public enum AddonArgsType
     /// Contains argument data for Close.
     /// </summary>
     Close,
+
+    /// <summary>
+    /// Contains argument data for OnFocusChanged.
+    /// </summary>
+    FocusChanged,
 }

Dalamud/Game/Addon/Lifecycle/AddonEvent.cs

@@ -203,4 +203,14 @@ public enum AddonEvent
     /// Be aware this is only called for certain popup windows, it is not triggered when clicking on windows.
     /// </remarks>
     PostFocus,
+
+    /// <summary>
+    /// An event that is fired before an addon processes its FocusChanged method.
+    /// </summary>
+    PreFocusChanged,
+
+    /// <summary>
+    /// An event that is fired after a addon processes its FocusChanged method.
+    /// </summary>
+    PostFocusChanged,
 }

Dalamud/Game/Addon/Lifecycle/AddonVirtualTable.cs

@@ -42,6 +42,7 @@ internal unsafe class AddonVirtualTable : IDisposable
     private readonly AddonArgs onMouseOverArgs = new();
     private readonly AddonArgs onMouseOutArgs = new();
     private readonly AddonArgs focusArgs = new();
+    private readonly AddonFocusChangedArgs focusChangedArgs = new();
 
     private readonly AtkUnitBase* atkUnitBase;
 
@@ -63,6 +64,7 @@ internal unsafe class AddonVirtualTable : IDisposable
     private readonly AtkUnitBase.Delegates.OnMouseOver onMouseOverFunction;
     private readonly AtkUnitBase.Delegates.OnMouseOut onMouseOutFunction;
     private readonly AtkUnitBase.Delegates.Focus focusFunction;
+    private readonly AtkUnitBase.Delegates.OnFocusChange onFocusChangeFunction;
 
     /// <summary>
     /// Initializes a new instance of the <see cref="AddonVirtualTable"/> class.
@@ -103,6 +105,7 @@ internal unsafe class AddonVirtualTable : IDisposable
         this.onMouseOverFunction = this.OnAddonMouseOver;
         this.onMouseOutFunction = this.OnAddonMouseOut;
         this.focusFunction = this.OnAddonFocus;
+        this.onFocusChangeFunction = this.OnAddonFocusChange;
 
         // Overwrite specific virtual table entries
         this.ModifiedVirtualTable->Dtor = (delegate* unmanaged<AtkUnitBase*, byte, AtkEventListener*>)Marshal.GetFunctionPointerForDelegate(this.destructorFunction);
@@ -121,6 +124,7 @@ internal unsafe class AddonVirtualTable : IDisposable
         this.ModifiedVirtualTable->OnMouseOver = (delegate* unmanaged<AtkUnitBase*, void>)Marshal.GetFunctionPointerForDelegate(this.onMouseOverFunction);
         this.ModifiedVirtualTable->OnMouseOut = (delegate* unmanaged<AtkUnitBase*, void>)Marshal.GetFunctionPointerForDelegate(this.onMouseOutFunction);
         this.ModifiedVirtualTable->Focus = (delegate* unmanaged<AtkUnitBase*, void>)Marshal.GetFunctionPointerForDelegate(this.focusFunction);
+        this.ModifiedVirtualTable->OnFocusChange = (delegate* unmanaged<AtkUnitBase*, bool, void>)Marshal.GetFunctionPointerForDelegate(this.onFocusChangeFunction);
     }
 
     /// <summary>
@@ -630,6 +634,36 @@ internal unsafe class AddonVirtualTable : IDisposable
         }
     }
 
+    private void OnAddonFocusChange(AtkUnitBase* thisPtr, bool isFocused)
+    {
+        try
+        {
+            this.LogEvent(EnableLogging);
+
+            this.focusChangedArgs.Addon = thisPtr;
+            this.focusChangedArgs.ShouldFocus = isFocused;
+
+            this.lifecycleService.InvokeListenersSafely(AddonEvent.PreFocusChanged, this.focusChangedArgs);
+
+            isFocused = this.focusChangedArgs.ShouldFocus;
+
+            try
+            {
+                this.OriginalVirtualTable->OnFocusChange(thisPtr, isFocused);
+            }
+            catch (Exception e)
+            {
+                Log.Error(e, "Caught exception when calling original Addon OnFocusChanged. This may be a bug in the game or another plugin hooking this method.");
+            }
+
+            this.lifecycleService.InvokeListenersSafely(AddonEvent.PostFocusChanged, this.focusChangedArgs);
+        }
+        catch (Exception e)
+        {
+            Log.Error(e, "Caught exception from Dalamud when attempting to process OnAddonFocusChange.");
+        }
+    }
+
     [Conditional("DEBUG")]
     private void LogEvent(bool loggingEnabled, [CallerMemberName] string caller = "")
     {