From 33b1f7b4743db58d179bcbc9de3a5c5920e6a5de Mon Sep 17 00:00:00 2001
From: bruned <30997009+bruned12@users.noreply.github.com>
Date: Sun, 20 Aug 2023 22:04:53 +0800
Subject: [PATCH] Update SlabGuide.java

Fix cant place slab
---
 .../v1_20/guides/placement/SlabGuide.java     | 33 ++++++++++++++++---
 1 file changed, 29 insertions(+), 4 deletions(-)

diff --git a/v1_20/src/main/java/me/aleksilassila/litematica/printer/v1_20/guides/placement/SlabGuide.java b/v1_20/src/main/java/me/aleksilassila/litematica/printer/v1_20/guides/placement/SlabGuide.java
index 449a5c8af..432f873fe 100644
--- a/v1_20/src/main/java/me/aleksilassila/litematica/printer/v1_20/guides/placement/SlabGuide.java
+++ b/v1_20/src/main/java/me/aleksilassila/litematica/printer/v1_20/guides/placement/SlabGuide.java
@@ -17,10 +17,35 @@ 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