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 448fa4f4f200430d6ce3051763c7ceb697696146..ca2052804ad829a1528a9c5a0a792275beead113 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
@@ -44,6 +44,7 @@ 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;
@@ -324,6 +325,21 @@ 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();
 
@@ -409,6 +425,7 @@ public abstract class AbstractFurnaceBlockEntity extends BaseContainerBlockEntit
             setChanged(world, pos, state);
         }
 
+        if (usedLavaFromUnderneath) blockEntity.items.set(1, ItemStack.EMPTY); // Purpur
     }
 
     private static boolean canBurn(RegistryAccess registryManager, @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 a721eb79dc528ada6a08265bb1f2895c31f0386e..5c478488da15171d70c1b4c01d7ca33698314032 100644
--- a/src/main/java/org/purpurmc/purpur/PurpurWorldConfig.java
+++ b/src/main/java/org/purpurmc/purpur/PurpurWorldConfig.java
@@ -413,6 +413,17 @@ 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 int lavaInfiniteRequiredSources = 2;
     public int lavaSpeedNether = 10;
     public int lavaSpeedNotNether = 30;