feat(ecs): add component removed event

2 files changed, 71 insertions, 2 deletions

diff --git a/ecs/src/event/component.rs b/ecs/src/event/component.rs
index 306d43f..4628cb1 100644
--- a/ecs/src/event/component.rs
+++ b/ecs/src/event/component.rs
@@ -54,11 +54,59 @@ where
     }
 }
 
+/// Event emitted when a `ComponentT` component is removed from a entity.
+pub struct Removed<ComponentT>
+where
+    ComponentT: Component,
+{
+    _pd: PhantomData<ComponentT>,
+}
+
+impl<ComponentT> Debug for Removed<ComponentT>
+where
+    ComponentT: Component,
+{
+    fn fmt(&self, formatter: &mut Formatter<'_>) -> std::fmt::Result
+    {
+        formatter
+            .debug_struct("Removed")
+            .field("_pd", &self._pd)
+            .finish()
+    }
+}
+
+impl<ComponentT> Default for Removed<ComponentT>
+where
+    ComponentT: Component,
+{
+    fn default() -> Self
+    {
+        Self { _pd: PhantomData }
+    }
+}
+
+impl<ComponentT> Event for Removed<ComponentT>
+where
+    ComponentT: Component,
+{
+    fn id() -> Id
+    where
+        Self: Sized,
+    {
+        Id::new::<Removed<ComponentForId>, _>(Some(ComponentId::of::<ComponentT>()))
+    }
+}
+
 pub fn create_added_id(component_id: ComponentId) -> Id
 {
     Id::new::<Added<ComponentForId>, _>(Some(component_id))
 }
 
+pub fn create_removed_id(component_id: ComponentId) -> Id
+{
+    Id::new::<Removed<ComponentForId>, _>(Some(component_id))
+}
+
 pub struct ComponentToAddedEvent;
 
 impl<ComponentT: Component, Accumulator>
diff --git a/ecs/src/lib.rs b/ecs/src/lib.rs
index ed2ccef..39b6bf3 100644
--- a/ecs/src/lib.rs
+++ b/ecs/src/lib.rs
@@ -14,6 +14,7 @@ use crate::component::{Component, Id as ComponentId, Sequence as ComponentSequen
 use crate::entity::Uid as EntityUid;
 use crate::event::component::{
     create_added_id as create_component_added_event_id,
+    create_removed_id as create_component_removed_event_id,
     ComponentToAddedEvent,
 };
 use crate::event::start::Start as StartEvent;
@@ -238,7 +239,7 @@ impl World
                         ));
                     }
                 }
-                Action::RemoveComponents(entity_uid, component_ids) => {
+                Action::RemoveComponents(entity_uid, components_metadata) => {
                     let mut component_storage_lock =
                         self.data.component_storage.write_nonblock().expect(
                             "Failed to acquire read-write component storage lock",
@@ -246,10 +247,30 @@ impl World
 
                     component_storage_lock.remove_components_from_entity(
                         entity_uid,
-                        component_ids
+                        components_metadata
                             .iter()
                             .map(|component_metadata| component_metadata.id),
                     );
+
+                    drop(component_storage_lock);
+
+                    if !has_swapped_active_queue {
+                        let mut active_queue =
+                            self.data.action_queue.active_queue.borrow_mut();
+
+                        *active_queue = match *active_queue {
+                            ActiveActionQueue::A => ActiveActionQueue::B,
+                            ActiveActionQueue::B => ActiveActionQueue::A,
+                        };
+
+                        has_swapped_active_queue = true;
+                    }
+
+                    for component_metadata in components_metadata {
+                        self.emit_event_by_id(create_component_removed_event_id(
+                            component_metadata.id,
+                        ));
+                    }
                 }
                 Action::Stop => {
                     self.stop.store(true, Ordering::Relaxed);