check arbitrary table actually exists

ported directly from my mods' solution.
could probably use clean-up with how the pools use air as a dummy "no result" item, a more Cobblemon-friendly loot table for Pickup, and I'd like to extend it with predicates that would need to match pokemonproperties for things like levels.

common/src/main/kotlin/com/cobblemon/mod/common/Cobblemon.kt

@@ -123,8 +123,14 @@ import net.minecraft.command.argument.serialize.ConstantArgumentSerializer
 import net.minecraft.entity.data.TrackedDataHandlerRegistry
 import net.minecraft.item.Items
 import net.minecraft.item.NameTagItem
+import net.minecraft.loot.LootDataType
+import net.minecraft.loot.context.LootContextParameterSet
+import net.minecraft.loot.context.LootContextParameters
 import net.minecraft.registry.RegistryKey
+import net.minecraft.server.world.ServerWorld
+import net.minecraft.util.Identifier
 import net.minecraft.util.WorldSavePath
+import net.minecraft.util.math.Vec3d
 import net.minecraft.world.World
 import org.apache.logging.log4j.LogManager
 import org.apache.logging.log4j.Logger
@@ -264,6 +270,52 @@ object Cobblemon {
             event.newFriendship = event.pokemon.friendship + increment.roundToInt()
         }
 
+        CobblemonEvents.BATTLE_VICTORY.subscribe(Priority.NORMAL) { evt ->
+            val world = evt.winners.flatMap { it.pokemonList }.firstNotNullOfOrNull { it.entity?.world }
+            if (world?.server == null) return@subscribe
+            for (winner in evt.winners) {
+                val position = winner.pokemonList.firstNotNullOf { it.entity }.blockPos
+                val vecPos = Vec3d(position.x.toDouble(), position.y.toDouble(), position.z.toDouble())
+                for (battlePokemon in winner.pokemonList) {
+                    val pokemon = battlePokemon.effectedPokemon
+//                    println("Rolling for ${pokemon.ability.name} on ${pokemon.getDisplayName().string}")
+
+                    if (!pokemon.heldItem().isEmpty) {
+//                        println("${pokemon.getDisplayName().string} is already holding an item")
+                        continue
+                    }
+
+                    val identifier = Identifier("cobblemon", "gameplay/abilities/postbattle/${pokemon.ability.name}")
+                    val lootManager = world.server!!.lootManager
+
+                    if (!lootManager.getIds(LootDataType.LOOT_TABLES).contains(identifier)) {
+//                        println("${pokemon.ability.name} doesn't have a postbattle loot table")
+                        continue
+                    }
+
+                    val lootTable = lootManager.getLootTable(identifier)
+
+                    val list = lootTable.generateLoot(
+                        LootContextParameterSet(
+                            world as ServerWorld,
+                            mapOf(
+                                LootContextParameters.ORIGIN to vecPos
+                            ),
+                            mapOf(),
+                            0F
+                        )
+                    )
+
+                    if (list.isEmpty) {
+//                        println("Attempted to roll for ability ${pokemon.ability.name} but nothing dropped.")
+                        continue
+                    }
+
+                    pokemon.swapHeldItem(list.first())
+                }
+            }
+        }
+
         HeldItemProvider.register(CobblemonHeldItemManager, Priority.LOWEST)
     }
 

common/src/main/resources/data/cobblemon/loot_tables/gameplay/abilities/postbattle/honeygather.json

@@ -0,0 +1,20 @@
+{
+  "type": "minecraft:generic",
+  "pools": [
+    {
+      "rolls": 1,
+      "entries": [
+        {
+          "type": "minecraft:item",
+          "name": "minecraft:air",
+          "weight": 9
+        },
+        {
+          "type": "minecraft:item",
+          "weight": 1,
+          "name": "minecraft:honey_bottle"
+        }
+      ]
+    }
+  ]
+}

common/src/main/resources/data/cobblemon/loot_tables/gameplay/abilities/postbattle/pickup.json

@@ -0,0 +1,65 @@
+{
+  "type": "minecraft:generic",
+  "pools": [
+    {
+      "rolls": 1,
+      "entries": [
+        {
+          "type": "minecraft:item",
+          "name": "minecraft:air",
+          "weight": 900
+        },
+        {
+          "type": "minecraft:item",
+          "weight": 30,
+          "name": "cobblemon:super_potion"
+        },
+        {
+          "type": "minecraft:item",
+          "weight": 10,
+          "name": "cobblemon:ultra_ball"
+        },
+        {
+          "type": "minecraft:item",
+          "weight": 10,
+          "name": "cobblemon:full_restore"
+        },
+        {
+          "type": "minecraft:item",
+          "weight": 10,
+          "name": "cobblemon:full_heal"
+        },
+        {
+          "type": "minecraft:item",
+          "weight": 10,
+          "name": "minecraft:gold_nugget"
+        },
+        {
+          "type": "minecraft:item",
+          "weight": 10,
+          "name": "cobblemon:revive"
+        },
+        {
+          "type": "minecraft:item",
+          "weight": 10,
+          "name": "cobblemon:rare_candy"
+        },
+        {
+          "type": "minecraft:item",
+          "weight": 5,
+          "name": "cobblemon:protein"
+        },
+        {
+          "type": "minecraft:item",
+          "weight": 4,
+          "name": "cobblemon:pp_up"
+        },
+        {
+          "type": "minecraft:item",
+          "weight": 1,
+          "name": "cobblemon:kings_rock"
+        }
+      ]
+    }
+  ]
+}