add kick system

scripts/Enemy.gd

@@ -18,6 +18,7 @@ var chain_factor: float = 0.65
 var stun_time: float = 0.5
 var base_scale: float = 1.0
 var wave_num: int = 1
+var damage_modifier: float = 0.75
 
 var state: State = State.CHASING
 var fly_vel: Vector3 = Vector3.ZERO
@@ -140,14 +141,18 @@ func _fly(delta: float) -> void:
 			hit_wall = true
 			break
 		elif col3d.is_in_group("enemies") and col3d != self:
-			var other: Node = col3d		
-			if speed_now >= 3.0 and other.get("enemy_level") == enemy_level and other.get("is_upgrading") == false and is_upgrading == false:
-				_start_merge(other)
-			else:
+			var merged := KickSystem.resolve(self, col3d, fly_vel)
+			if not merged and is_instance_valid(col3d):
 				var chain_dir := col3d.global_position - global_position
 				chain_dir.y = 0.0
 				if chain_dir.length() > 0.01:
 					col3d.call("receive_kick", chain_dir.normalized(), speed_now * chain_factor)
+		elif col3d.is_in_group("rocks"):
+			KickSystem.resolve(self, col3d, fly_vel)
+			var rock_dir := col3d.global_position - global_position
+			rock_dir.y = 0.0
+			if rock_dir.length() > 0.01:
+				col3d.call("receive_kick", rock_dir.normalized(), speed_now * 0.5)
 		elif col3d.is_in_group("player"):
 			col3d.call("take_damage", int(speed_now * 0.6))
 
@@ -166,6 +171,19 @@ func _stun_tick(delta: float) -> void:
 	if stun_timer <= 0.0:
 		_enter_chase()
 
+func can_merge_with(other: Node3D, collision_speed: float) -> bool:
+	return (collision_speed >= 3.0
+		and other.get("enemy_type") == enemy_type
+		and other.get("enemy_level") == enemy_level
+		and not is_upgrading
+		and not other.get("is_upgrading"))
+
+func do_merge_with(other: Node3D) -> void:
+	_start_merge(other)
+
+func apply_collision_damage(dmg: float) -> void:
+	_take_hit(int(dmg))
+
 func receive_kick(direction: Vector3, force: float) -> void:
 	if state == State.DEAD:
 		return