From 8ab8ec9de30378277bd3128e7e19a9b443511980 Mon Sep 17 00:00:00 2001
From: Sollace <sollacea@gmail.com>
Date: Thu, 10 Aug 2023 12:44:38 +0100
Subject: [PATCH] Fix crash when looking at crops in certain situations

---
 .../unicopia/block/SegmentedBlock.java             | 14 ++++----------
 .../unicopia/block/SegmentedCropBlock.java         |  8 ++++----
 .../minelittlepony/unicopia/util/PosHelper.java    | 13 +++++++++++++
 3 files changed, 21 insertions(+), 14 deletions(-)

diff --git a/src/main/java/com/minelittlepony/unicopia/block/SegmentedBlock.java b/src/main/java/com/minelittlepony/unicopia/block/SegmentedBlock.java
index 441e9882..e374473e 100644
--- a/src/main/java/com/minelittlepony/unicopia/block/SegmentedBlock.java
+++ b/src/main/java/com/minelittlepony/unicopia/block/SegmentedBlock.java
@@ -1,10 +1,12 @@
 package com.minelittlepony.unicopia.block;
 
 import java.util.Arrays;
+import com.minelittlepony.unicopia.util.PosHelper;
 
 import net.minecraft.block.Block;
 import net.minecraft.block.BlockState;
 import net.minecraft.util.math.BlockPos;
+import net.minecraft.util.math.Direction;
 import net.minecraft.util.shape.VoxelShape;
 import net.minecraft.util.shape.VoxelShapes;
 import net.minecraft.world.BlockView;
@@ -46,18 +48,10 @@ public interface SegmentedBlock {
     boolean isNext(BlockState state);
 
     default BlockPos getTip(BlockView world, BlockPos startingPos) {
-        while (isNext(world.getBlockState(startingPos.up())) && !world.isOutOfHeightLimit(startingPos)) {
-            startingPos = startingPos.up();
-        }
-
-        return startingPos;
+        return PosHelper.traverseChain(world, startingPos, Direction.UP, this::isNext);
     }
 
     default BlockPos getRoot(BlockView world, BlockPos startingPos) {
-        while (isBase(world.getBlockState(startingPos.down())) && !world.isOutOfHeightLimit(startingPos)) {
-            startingPos = startingPos.down();
-        }
-
-        return startingPos;
+        return PosHelper.traverseChain(world, startingPos, Direction.DOWN, this::isBase);
     }
 }
diff --git a/src/main/java/com/minelittlepony/unicopia/block/SegmentedCropBlock.java b/src/main/java/com/minelittlepony/unicopia/block/SegmentedCropBlock.java
index 97e0225e..36c6b924 100644
--- a/src/main/java/com/minelittlepony/unicopia/block/SegmentedCropBlock.java
+++ b/src/main/java/com/minelittlepony/unicopia/block/SegmentedCropBlock.java
@@ -76,7 +76,7 @@ public class SegmentedCropBlock extends CropBlock implements SegmentedBlock {
         int height = (tip.getY() - root.getY());
 
         BlockState tipState = world.getBlockState(tip);
-        double tipHeight = SegmentedBlock.getHeight(((SegmentedCropBlock)tipState.getBlock()).getAge(tipState));
+        double tipHeight = tipState.getBlock() instanceof SegmentedCropBlock tipBlock ? SegmentedBlock.getHeight(tipBlock.getAge(tipState)) : 0;
 
         double offset = (root.getY() - pos.getY()) * 16;
 
@@ -106,16 +106,16 @@ public class SegmentedCropBlock extends CropBlock implements SegmentedBlock {
     @Override
     public void randomTick(BlockState state, ServerWorld world, BlockPos pos, Random random) {
         BlockPos tip = getTip(world, pos);
-        BlockPos base = getRoot(world, pos);
+        BlockPos root = getRoot(world, pos);
 
-        if (base.getY() != pos.getY()) {
+        if (root.getY() != pos.getY()) {
             return;
         }
 
         if (world.getBaseLightLevel(tip, 0) >= 9) {
             int age = getAge(state);
             if (age < getMaxAge()) {
-                float moisture = CropBlock.getAvailableMoisture(world.getBlockState(base).getBlock(), world, base);
+                float moisture = CropBlock.getAvailableMoisture(world.getBlockState(root).getBlock(), world, root);
                 if (random.nextInt((int)(BASE_GROWTH_CHANCE / moisture) + 1) == 0) {
                     world.setBlockState(pos, withAge(age + 1), Block.NOTIFY_LISTENERS);
                     propagateGrowth(world, pos, state);
diff --git a/src/main/java/com/minelittlepony/unicopia/util/PosHelper.java b/src/main/java/com/minelittlepony/unicopia/util/PosHelper.java
index 587e1bbb..603a2c2c 100644
--- a/src/main/java/com/minelittlepony/unicopia/util/PosHelper.java
+++ b/src/main/java/com/minelittlepony/unicopia/util/PosHelper.java
@@ -11,11 +11,13 @@ import java.util.stream.StreamSupport;
 
 import com.google.common.collect.Lists;
 
+import net.minecraft.block.BlockState;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.util.math.Direction;
 import net.minecraft.util.math.Direction.Axis;
 import net.minecraft.util.math.Vec3d;
 import net.minecraft.util.math.Vec3i;
+import net.minecraft.world.BlockView;
 import net.minecraft.world.World;
 
 public interface PosHelper {
@@ -65,4 +67,15 @@ public interface PosHelper {
             }
         }, false);
     }
+
+    static BlockPos traverseChain(BlockView world, BlockPos startingPos, Direction chainDirection, Predicate<BlockState> isInChain) {
+        BlockPos.Mutable mutablePos = new BlockPos.Mutable();
+        mutablePos.set(startingPos);
+        do {
+            mutablePos.move(chainDirection);
+        } while (isInChain.test(world.getBlockState(mutablePos)) && !world.isOutOfHeightLimit(mutablePos));
+
+        mutablePos.move(chainDirection.getOpposite());
+        return mutablePos.toImmutable();
+    }
 }