Fix fluids destroying tripwire-backed blocks

Relates to #432

nova/src/main/kotlin/xyz/xenondevs/nova/patch/impl/block/TripwireLogicPatch.kt

@@ -1,27 +1,55 @@
 package xyz.xenondevs.nova.patch.impl.block
 
 import net.minecraft.core.BlockPos
+import net.minecraft.world.level.BlockGetter
 import net.minecraft.world.level.Level
+import net.minecraft.world.level.block.Blocks
 import net.minecraft.world.level.block.TripWireHookBlock
 import net.minecraft.world.level.block.state.BlockState
+import net.minecraft.world.level.material.FlowingFluid
+import net.minecraft.world.level.material.Fluid
 import org.objectweb.asm.Opcodes
+import org.objectweb.asm.tree.LabelNode
 import org.objectweb.asm.tree.MethodInsnNode
+import xyz.xenondevs.bytebase.asm.buildInsnList
 import xyz.xenondevs.bytebase.jvm.VirtualClassPath
 import xyz.xenondevs.bytebase.util.calls
 import xyz.xenondevs.bytebase.util.replaceEvery
 import xyz.xenondevs.nova.patch.MultiTransformer
+import xyz.xenondevs.nova.util.reflection.ReflectionUtils
 import xyz.xenondevs.nova.util.toNovaPos
 import xyz.xenondevs.nova.world.block.DefaultBlocks
 import xyz.xenondevs.nova.world.block.behavior.TripwireBehavior
 import xyz.xenondevs.nova.world.format.WorldDataManager
 
-internal object TripwireLogicPatch : MultiTransformer(TripWireHookBlock::class) {
+private val FLOWING_FLUID_CAN_HOLD_FLUID = ReflectionUtils.getMethod(
+    FlowingFluid::class, 
+    "canHoldFluid",
+    BlockGetter::class, BlockPos::class, BlockState::class, Fluid::class
+)
+
+internal object TripwireLogicPatch : MultiTransformer(TripWireHookBlock::class, FlowingFluid::class) {
 
     override fun transform() {
         VirtualClassPath[TripWireHookBlock::calculateState].replaceEvery(
             0, 0,
             { invokeStatic(::getBlockState) }
         ) {it.opcode == Opcodes.INVOKEVIRTUAL && (it as MethodInsnNode).calls(Level::getBlockState)}
+
+        VirtualClassPath[FLOWING_FLUID_CAN_HOLD_FLUID].instructions.insert(buildInsnList { 
+            addLabel()
+            aLoad(1) // level
+            aLoad(2) // pos
+            aLoad(3) // state
+            invokeStatic(::cannotHoldFluid)
+
+            // if (cannotHoldFluid(level, pos, state)) return false
+            val continueLabel = LabelNode()
+            ifeq(continueLabel)
+            ldc(0)
+            ireturn()
+            add(continueLabel)
+        })
     }
 
     @JvmStatic
@@ -35,4 +63,18 @@ internal object TripwireLogicPatch : MultiTransformer(TripWireHookBlock::class)
         return level.getBlockState(pos)
     }
 
+    @JvmStatic
+    fun cannotHoldFluid(level: BlockGetter, pos: BlockPos, state: BlockState): Boolean {
+        if (level !is Level)
+            return false
+
+        if (state.block == Blocks.TRIPWIRE) {
+            val novaState = WorldDataManager.getBlockState(pos.toNovaPos(level.world))
+            if (novaState != null && novaState.block != DefaultBlocks.TRIPWIRE)
+                return true
+        }
+
+        return false
+    }
+
 }