cactus and block rotator

src/main/java/carpet/mixins/HopperBlock_cactusMixin.java

@@ -0,0 +1,26 @@
+package carpet.mixins;
+
+import carpet.helpers.BlockRotator;
+import net.minecraft.block.HopperBlock;
+import net.minecraft.item.ItemPlacementContext;
+import net.minecraft.util.math.Direction;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Redirect;
+
+@Mixin(HopperBlock.class)
+public class HopperBlock_cactusMixin
+{
+    @Redirect(method = "getPlacementState", at = @At(
+            value = "INVOKE",
+            target = "Lnet/minecraft/item/ItemPlacementContext;getSide()Lnet/minecraft/util/math/Direction;"
+    ))
+    private Direction getOppositeOpposite(ItemPlacementContext context)
+    {
+        if (BlockRotator.flippinEligibility(context.getPlayer()))
+        {
+            return context.getSide().getOpposite();
+        }
+        return context.getSide();
+    }
+}