From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: William Blake Galbreath <Blake.Galbreath@GMail.com>
Date: Mon, 19 Oct 2020 15:14:01 -0500
Subject: [PATCH] Furnace uses lava from underneath


diff --git a/src/main/java/net/minecraft/world/level/block/entity/AbstractFurnaceBlockEntity.java b/src/main/java/net/minecraft/world/level/block/entity/AbstractFurnaceBlockEntity.java
index cac2768fe520b591990c7bc943ae7e95f49efb31..bbff7466cecf50285c97fadaf68682a6c6ea879f 100644
--- a/src/main/java/net/minecraft/world/level/block/entity/AbstractFurnaceBlockEntity.java
+++ b/src/main/java/net/minecraft/world/level/block/entity/AbstractFurnaceBlockEntity.java
@@ -43,6 +43,7 @@ import net.minecraft.world.level.Level;
 import net.minecraft.world.level.block.AbstractFurnaceBlock;
 import net.minecraft.world.level.block.Blocks;
 import net.minecraft.world.level.block.state.BlockState;
+import net.minecraft.world.level.material.FluidState;
 import net.minecraft.world.phys.Vec3;
 // CraftBukkit start
 import org.bukkit.craftbukkit.block.CraftBlock;
@@ -323,6 +324,21 @@ public abstract class AbstractFurnaceBlockEntity extends BaseContainerBlockEntit
         }
 
         ItemStack itemstack = (ItemStack) blockEntity.items.get(1);
+        // Purpur start
+        boolean usedLavaFromUnderneath = false;
+        if (world.purpurConfig.furnaceUseLavaFromUnderneath && !blockEntity.isLit() && itemstack.isEmpty() && !blockEntity.items.get(0).isEmpty() && world.getGameTime() % 20 == 0) {
+            BlockPos below = blockEntity.getBlockPos().below();
+            BlockState belowState = world.getBlockStateIfLoaded(below);
+            if (belowState != null && belowState.is(Blocks.LAVA)) {
+                FluidState fluidState = belowState.getFluidState();
+                if (fluidState != null && fluidState.isSource()) {
+                    world.setBlock(below, Blocks.AIR.defaultBlockState(), 3);
+                    itemstack = Items.LAVA_BUCKET.getDefaultInstance();
+                    usedLavaFromUnderneath = true;
+                }
+            }
+        }
+        // Purpur end
         boolean flag2 = !((ItemStack) blockEntity.items.get(0)).isEmpty();
         boolean flag3 = !itemstack.isEmpty();
 
@@ -408,6 +424,7 @@ public abstract class AbstractFurnaceBlockEntity extends BaseContainerBlockEntit
             setChanged(world, pos, state);
         }
 
+        if (usedLavaFromUnderneath) blockEntity.items.set(1, ItemStack.EMPTY); // Purpur
     }
 
     private static boolean canBurn(@Nullable Recipe<?> recipe, NonNullList<ItemStack> slots, int count) {
diff --git a/src/main/java/org/purpurmc/purpur/PurpurWorldConfig.java b/src/main/java/org/purpurmc/purpur/PurpurWorldConfig.java
index c15e6d7a666ddde4d6fc957ca2986d4af3eaebf9..3593489c838c514be2703d7f81e2eb825fc5cd1b 100644
--- a/src/main/java/org/purpurmc/purpur/PurpurWorldConfig.java
+++ b/src/main/java/org/purpurmc/purpur/PurpurWorldConfig.java
@@ -416,6 +416,17 @@ public class PurpurWorldConfig {
         farmlandGetsMoistFromBelow = getBoolean("blocks.farmland.gets-moist-from-below", farmlandGetsMoistFromBelow);
     }
 
+    public boolean furnaceUseLavaFromUnderneath = false;
+    private void furnaceSettings() {
+        if (PurpurConfig.version < 17) {
+            furnaceUseLavaFromUnderneath = getBoolean("blocks.furnace.infinite-fuel", furnaceUseLavaFromUnderneath);
+            boolean oldValue = getBoolean("blocks.furnace.infinite-fuel", furnaceUseLavaFromUnderneath);
+            set("blocks.furnace.infinite-fuel", null);
+            set("blocks.furnace.use-lava-from-underneath", oldValue);
+        }
+        furnaceUseLavaFromUnderneath = getBoolean("blocks.furnace.use-lava-from-underneath", furnaceUseLavaFromUnderneath);
+    }
+
     public boolean lavaInfinite = false;
     public int lavaInfiniteRequiredSources = 2;
     public int lavaSpeedNether = 10;