More genuine container contents shuffling

src/main/kotlin/ru/dbotthepony/kstarbound/item/IContainer.kt

@@ -2,6 +2,7 @@ package ru.dbotthepony.kstarbound.item
 
 import com.google.gson.JsonArray
 import com.google.gson.JsonElement
+import it.unimi.dsi.fastutil.ints.IntArrayList
 import ru.dbotthepony.kstarbound.Starbound
 import ru.dbotthepony.kstarbound.defs.item.ItemDescriptor
 import java.util.random.RandomGenerator
@@ -50,7 +51,7 @@ interface IContainer {
 		return count
 	}
 
-	fun shuffle(random: RandomGenerator) {
+	fun shuffle(random: RandomGenerator, split: Boolean = true, splitChance: Float = 0.8f) {
 		for (i in 0 until size) {
 			val rand = random.nextInt(size)
 			val a = this[i]
@@ -59,6 +60,53 @@ interface IContainer {
 			this[rand] = a
 			this[i] = b
 		}
+
+		if (split) {
+			val emptySlots = IntArrayList()
+			val splittableSlots = IntArrayList()
+
+			for (i in 0 until size) {
+				if (this[i].isEmpty) {
+					emptySlots.add(i)
+				} else if (this[i].size > 1L) {
+					splittableSlots.add(i)
+				}
+			}
+
+			if (splittableSlots.isNotEmpty() && emptySlots.isNotEmpty()) {
+				for (tslot in splittableSlots) {
+					if (emptySlots.isEmpty)
+						break
+
+					if (random.nextFloat() <= splitChance) {
+						var currentChance = splitChance
+						val workingSlots = IntArrayList()
+						workingSlots.add(tslot)
+
+						while (workingSlots.isNotEmpty() && emptySlots.isNotEmpty()) {
+							val slot = workingSlots.removeInt(0)
+							val item = this[slot]
+							val splitAmount = random.nextLong(1L, item.size)
+							val copy = item.copy(splitAmount)
+							item.size -= splitAmount
+
+							val targetSlot = emptySlots.removeInt(random.nextInt(emptySlots.size))
+							this[targetSlot] = copy
+
+							currentChance *= 0.75f
+
+							if (item.size > 1L && random.nextFloat() <= currentChance) {
+								workingSlots.add(slot)
+							}
+
+							if (splitAmount > 1L && random.nextFloat() <= currentChance) {
+								workingSlots.add(targetSlot)
+							}
+						}
+					}
+				}
+			}
+		}
 	}
 
 	// puts item into container, returns remaining not put items