c3

src/main/java/moe/lava/cartloader/impl/MixinPlayerEntityImpl.kt

@@ -1,4 +1,42 @@
 package moe.lava.cartloader.impl
 
+import moe.lava.cartloader.accessor.AccessorAbstractMinecartEntity
+import net.minecraft.entity.Entity
+import net.minecraft.entity.ItemEntity
+import net.minecraft.entity.player.PlayerEntity
+import net.minecraft.entity.vehicle.AbstractMinecartEntity
+import net.minecraft.item.Items
+import net.minecraft.util.ActionResult
+import net.minecraft.util.Hand
+
 class MixinPlayerEntityImpl {
+    private var linking: AbstractMinecartEntity? = null
+    fun interact(minecart: Entity, player: PlayerEntity, hand: Hand): ActionResult? {
+        if (minecart !is AbstractMinecartEntity)
+            return null
+
+        if (minecart !is AccessorAbstractMinecartEntity)
+            return null;
+
+        if (!player.getStackInHand(hand).isOf(Items.CHAIN))
+            return null
+
+        val target = linking
+        if (target == null) {
+            linking = minecart
+            return ActionResult.SUCCESS
+        }
+        if (target !is AccessorAbstractMinecartEntity)
+            return null
+
+        linking = null
+        if (!target.isAlive)
+            return ActionResult.FAIL
+
+        if (!minecart.boundingBox.expand(0.1).intersects(target.boundingBox))
+            return ActionResult.FAIL
+
+        target.`cartloader$getImpl`().linkTo(minecart)
+        return ActionResult.SUCCESS
+    }
 }