From efb864f413788e59c8b4d04add9b3aea209e66d8 Mon Sep 17 00:00:00 2001
From: Aleksi Lassila <aleksi.emil.lassila@gmail.com>
Date: Tue, 29 Oct 2024 21:19:01 +0200
Subject: [PATCH] Merge pull request #188 from bruned12/printer-1.20.1-3.2.1

Fix cant place slab

(cherry picked from commit 2357b374d3223f3132e3f710279dc5158ff8a926)
---
 .../printer/guides/placement/SlabGuide.java   | 34 ++++++++++++++++---
 1 file changed, 30 insertions(+), 4 deletions(-)

diff --git a/src/main/java/me/aleksilassila/litematica/printer/guides/placement/SlabGuide.java b/src/main/java/me/aleksilassila/litematica/printer/guides/placement/SlabGuide.java
index ff9a03f68..8a08efbb4 100644
--- a/src/main/java/me/aleksilassila/litematica/printer/guides/placement/SlabGuide.java
+++ b/src/main/java/me/aleksilassila/litematica/printer/guides/placement/SlabGuide.java
@@ -7,6 +7,7 @@
 import net.minecraft.util.math.Direction;
 import net.minecraft.util.math.Vec3d;
 
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 
@@ -17,10 +18,35 @@ public SlabGuide(SchematicBlockState state) {
 
     @Override
     protected List<Direction> getPossibleSides() {
-        return Arrays.stream(Direction.values())
-                .filter(d -> d != (getRequiredHalf(state).getOpposite()) &&
-                        getProperty(state.offset(d).currentState, SlabBlock.TYPE).orElse(SlabType.DOUBLE) == SlabType.DOUBLE)
-                .toList();
+        List<Direction> resultList = new ArrayList<>();
+        SlabType targetSlabType = getProperty(state.targetState, SlabBlock.TYPE).orElse(SlabType.DOUBLE);
+
+        if (targetSlabType == SlabType.DOUBLE) {
+            return super.getPossibleSides();
+        }
+
+        Direction[] directionsToCheck = {
+                Direction.NORTH, Direction.SOUTH, Direction.WEST, Direction.EAST
+        };
+
+        for (Direction direction : directionsToCheck) {
+            SlabType neighborSlabType = getProperty(state.offset(direction).currentState, SlabBlock.TYPE).orElse(SlabType.DOUBLE);
+
+            if (neighborSlabType == SlabType.DOUBLE || neighborSlabType == targetSlabType) {
+                resultList.add(direction);
+            }
+        }
+
+        if (targetSlabType == SlabType.TOP || targetSlabType == SlabType.BOTTOM) {
+            Direction verticalDirection = targetSlabType == SlabType.TOP ? Direction.UP : Direction.DOWN;
+            SlabType neighborSlabType = getProperty(state.offset(verticalDirection).currentState, SlabBlock.TYPE).orElse(SlabType.DOUBLE);
+
+            if (neighborSlabType == SlabType.DOUBLE || neighborSlabType != targetSlabType) {
+                resultList.add(verticalDirection);
+            }
+        }
+
+        return resultList;
     }
 
     @Override