Snapshot change events on each frame, to avoid event spam when attached inventory

reconstruct slot list (hi Ender Rift)

src/main/kotlin/ru/dbotthepony/mc/otm/block/entity/storage/StorageBusBlockEntity.kt

@@ -28,6 +28,7 @@ import ru.dbotthepony.mc.otm.capability.WorkerEnergyStorage
 import ru.dbotthepony.mc.otm.container.ItemFilter
 import ru.dbotthepony.mc.otm.core.ImpreciseFraction
 import ru.dbotthepony.mc.otm.core.isPositive
+import ru.dbotthepony.mc.otm.core.isZero
 import ru.dbotthepony.mc.otm.core.plus
 import ru.dbotthepony.mc.otm.graph.Graph6Node
 import ru.dbotthepony.mc.otm.graph.GraphNodeListener
@@ -186,6 +187,55 @@ class StorageBusBlockEntity(blockPos: BlockPos, blockState: BlockState) : Matter
 	}
 
 	private inner class ItemHandlerComponent(private val parent: IItemHandler) : IStorageComponent<ItemStackWrapper> {
+		private inner class EventsSnapshot {
+			val index = Long2ObjectAVLTreeMap<BigInteger>()
+
+			fun change(key: Long, diff: BigInteger) {
+				if (diff.isZero)
+					return
+
+				val value = index[key]
+
+				if (value == null) {
+					index[key] = diff
+				} else {
+					val newvalue = value + diff
+
+					if (newvalue.isZero) {
+						index.remove(key)
+					} else {
+						index[key] = newvalue
+					}
+				}
+			}
+
+			fun apply() {
+				for ((key, value) in index) {
+					val tuple = checkNotNull(this@ItemHandlerComponent.index[key]) { "Tuple with ID $key is missing!" }
+
+					val count = tuple.stack.count
+					tuple.stack.count += value
+
+					if (tuple.stack.count.isPositive) {
+						for (listener in listeners) {
+							listener.changeStack(tuple, count)
+						}
+					} else {
+						for (listener in listeners) {
+							listener.removeStack(tuple)
+						}
+
+						this@ItemHandlerComponent.index.remove(tuple.id)
+
+						val tuplekey = tuple.stack.key()
+						tuples.remove(tuplekey) ?: throw IllegalStateException("Cross-reference integrity check failed for $tuple")
+					}
+				}
+			}
+		}
+
+		private var snapshot: EventsSnapshot? = null
+
 		override val storageType: StorageStackType<ItemStackWrapper>
 			get() = ITEM_STORAGE
 
@@ -219,21 +269,28 @@ class StorageBusBlockEntity(blockPos: BlockPos, blockState: BlockState) : Matter
 			val item = scannedMap.children[slot] ?: throw IllegalStateException("${scannedMap.id} does not track $slot")
 			scannedMap.children.remove(slot)
 			val count = scannedMap.stack.count
-			scannedMap.stack.count -= item.stack.count.toBigInteger()
 
-			if (scannedMap.stack.count.isPositive) {
-				for (listener in listeners) {
-					listener.changeStack(scannedMap, count)
-				}
+			val snapshot = snapshot
+
+			if (snapshot != null) {
+				snapshot.change(scannedMap.id, -item.stack.count.toBigInteger())
 			} else {
-				for (listener in listeners) {
-					listener.removeStack(scannedMap)
+				scannedMap.stack.count -= item.stack.count.toBigInteger()
+
+				if (scannedMap.stack.count.isPositive) {
+					for (listener in listeners) {
+						listener.changeStack(scannedMap, count)
+					}
+				} else {
+					for (listener in listeners) {
+						listener.removeStack(scannedMap)
+					}
+
+					index.remove(scannedMap.id)
+
+					val key = scannedMap.stack.key()
+					tuples.remove(key) ?: throw IllegalStateException("Item tuple is not present for slot $slot at ${scannedMap.stack}")
 				}
-
-				index.remove(scannedMap.id)
-
-				val key = scannedMap.stack.key()
-				tuples.remove(key) ?: throw IllegalStateException("Item tuple is not present for slot $slot at ${scannedMap.stack}")
 			}
 		}
 
@@ -243,10 +300,17 @@ class StorageBusBlockEntity(blockPos: BlockPos, blockState: BlockState) : Matter
 
 			val oldCount = scannedMap.stack.count
 			item.stack.count += diff
-			scannedMap.stack.count += diff.toBigInteger()
 
-			for (listener in listeners) {
-				listener.changeStack(scannedMap.stack, scannedMap.id, oldCount)
+			val snapshot = snapshot
+
+			if (snapshot != null) {
+				snapshot.change(scannedMap.id, diff.toBigInteger())
+			} else {
+				scannedMap.stack.count += diff.toBigInteger()
+
+				for (listener in listeners) {
+					listener.changeStack(scannedMap.stack, scannedMap.id, oldCount)
+				}
 			}
 		}
 
@@ -265,7 +329,9 @@ class StorageBusBlockEntity(blockPos: BlockPos, blockState: BlockState) : Matter
 				tuples[key] = tuple
 			} else {
 				oldCount = tuple!!.stack.count
-				tuple.stack.count += stack.count.toBigInteger()
+
+				if (snapshot == null)
+					tuple.stack.count += stack.count.toBigInteger()
 			}
 
 			tuple.children[slot] = SlotTuple(slot, stack.copy())
@@ -277,8 +343,14 @@ class StorageBusBlockEntity(blockPos: BlockPos, blockState: BlockState) : Matter
 					listener.addStack(tuple.stack, tuple.id, this)
 				}
 			} else {
-				for (listener in listeners) {
-					listener.changeStack(tuple.stack, tuple.id, oldCount)
+				val snapshot = snapshot
+
+				if (snapshot != null) {
+					snapshot.change(tuple.id, stack.count.toBigInteger())
+				} else {
+					for (listener in listeners) {
+						listener.changeStack(tuple.stack, tuple.id, oldCount)
+					}
 				}
 			}
 		}
@@ -339,9 +411,14 @@ class StorageBusBlockEntity(blockPos: BlockPos, blockState: BlockState) : Matter
 		fun scan() {
 			sizeScan()
 
+			snapshot = EventsSnapshot()
+
 			for (slot in 0 until parent.slots) {
 				scan(slot)
 			}
+
+			snapshot!!.apply()
+			snapshot = null
 		}
 
 		override fun insertStack(stack: ItemStackWrapper, simulate: Boolean): ItemStackWrapper {