feat: Add more complex entity equipment scraper

src/main/kotlin/events/EntityUpdateEvent.kt

@@ -7,6 +7,8 @@ import net.minecraft.entity.LivingEntity
 import net.minecraft.entity.data.DataTracker
 import net.minecraft.item.ItemStack
 import net.minecraft.network.packet.s2c.play.EntityAttributesS2CPacket
+import moe.nea.firmament.annotations.Subscribe
+import moe.nea.firmament.util.MC
 
 /**
  * This event is fired when some entity properties are updated.
@@ -15,7 +17,27 @@ import net.minecraft.network.packet.s2c.play.EntityAttributesS2CPacket
  * *after* the values have been applied to the entity.
  */
 sealed class EntityUpdateEvent : FirmamentEvent() {
-	companion object : FirmamentEventBus<EntityUpdateEvent>()
+	companion object : FirmamentEventBus<EntityUpdateEvent>() {
+		@Subscribe
+		fun onPlayerInventoryUpdate(event: PlayerInventoryUpdate) {
+			val p = MC.player ?: return
+			val updatedSlots = listOf(
+				EquipmentSlot.HEAD to 39,
+				EquipmentSlot.CHEST to 38,
+				EquipmentSlot.LEGS to 37,
+				EquipmentSlot.FEET to 36,
+				EquipmentSlot.OFFHAND to 40,
+				EquipmentSlot.MAINHAND to p.inventory.selectedSlot, // TODO: also equipment update when you swap your selected slot perhaps
+			).mapNotNull { (slot, stackIndex) ->
+				val slotIndex = p.playerScreenHandler.getSlotIndex(p.inventory, stackIndex).asInt
+				event.getOrNull(slotIndex)?.let {
+					Pair.of(slot, it)
+				}
+			}
+			if (updatedSlots.isNotEmpty())
+				publish(EquipmentUpdate(p, updatedSlots))
+		}
+	}
 
 	abstract val entity: Entity
 

src/main/kotlin/events/PlayerInventoryUpdate.kt

@@ -1,11 +1,22 @@
-
 package moe.nea.firmament.events
 
 import net.minecraft.item.ItemStack
 
 sealed class PlayerInventoryUpdate : FirmamentEvent() {
-    companion object : FirmamentEventBus<PlayerInventoryUpdate>()
-    data class Single(val slot: Int, val stack: ItemStack) : PlayerInventoryUpdate()
-    data class Multi(val contents: List<ItemStack>) : PlayerInventoryUpdate()
+	companion object : FirmamentEventBus<PlayerInventoryUpdate>()
+	data class Single(val slot: Int, val stack: ItemStack) : PlayerInventoryUpdate() {
+		override fun getOrNull(slot: Int): ItemStack? {
+			if (slot == this.slot) return stack
+			return null
+		}
 
+	}
+
+	data class Multi(val contents: List<ItemStack>) : PlayerInventoryUpdate() {
+		override fun getOrNull(slot: Int): ItemStack? {
+			return contents.getOrNull(slot)
+		}
+	}
+
+	abstract fun getOrNull(slot: Int): ItemStack?
 }