From e038c4295d50c31883066e886c03187684247eff Mon Sep 17 00:00:00 2001
From: "Dylan K. Taylor" <odigiman@gmail.com>
Date: Thu, 27 Sep 2018 18:46:01 +0100
Subject: [PATCH] Clean up abhorrent mess of Slab placement code

---
 src/pocketmine/block/Slab.php | 51 ++++++++++-------------------------
 1 file changed, 14 insertions(+), 37 deletions(-)

diff --git a/src/pocketmine/block/Slab.php b/src/pocketmine/block/Slab.php
index f138d1c97..d6b8fb63f 100644
--- a/src/pocketmine/block/Slab.php
+++ b/src/pocketmine/block/Slab.php
@@ -78,48 +78,25 @@ abstract class Slab extends Transparent{
 	}
 
 	public function place(Item $item, Block $blockReplace, Block $blockClicked, int $face, Vector3 $clickVector, Player $player = null) : bool{
-		if($face === Facing::DOWN){
-			if($blockClicked instanceof Slab and $blockClicked->isSameType($this) and $blockClicked->top){
-				$this->getLevel()->setBlock($blockClicked, $this->getDouble());
+		/* note these conditions can't be merged, since one targets clicked and the other replace */
 
-				return true;
-			}elseif($blockReplace->isSameType($this)){
-				$this->getLevel()->setBlock($blockReplace, $this->getDouble());
-
-				return true;
-			}else{
-				$this->top = true;
-			}
-		}elseif($face === Facing::UP){
-			if($blockClicked instanceof Slab and $blockClicked->isSameType($this) and !$blockClicked->top){
-				$this->getLevel()->setBlock($blockClicked, $this->getDouble());
-
-				return true;
-			}elseif($blockReplace->isSameType($this)){
-				$this->getLevel()->setBlock($blockReplace, $this->getDouble());
-
-				return true;
-			}
-		}else{ //TODO: collision
-			if($blockReplace->getId() === $this->getId()){
-				if($blockReplace->getVariant() === $this->variant){
-					$this->getLevel()->setBlock($blockReplace, $this->getDouble());
-
-					return true;
-				}
-
-				return false;
-			}else{
-				if($clickVector->y > 0.5){
-					$this->top = true;
-				}
-			}
+		if($blockClicked instanceof Slab and $blockClicked->isSameType($this) and (
+			($face === Facing::DOWN and $blockClicked->top) or //Bottom face of top slab
+			($face === Facing::UP and !$blockClicked->top) //Top face of bottom slab
+		)){
+			return $this->level->setBlock($blockClicked, $this->getDouble());
 		}
 
-		if($blockReplace->getId() === $this->getId() and $blockClicked->getVariant() !== $this->variant){
-			return false;
+		if($blockReplace instanceof Slab and $blockReplace->isSameType($this) and (
+			($blockReplace->top and $clickVector->y <= 0.5) or
+			(!$blockReplace->top and $clickVector->y >= 0.5)
+		)){
+			//Clicked in empty half of existing slab
+			return $this->level->setBlock($blockReplace, $this->getDouble());
 		}
 
+		$this->top = ($face !== Facing::UP && $clickVector->y > 0.5) || $face === Facing::DOWN;
+
 		return parent::place($item, $blockReplace, $blockClicked, $face, $clickVector, $player);
 	}