Packet: QuantityDeltaUpdateMessage (#57)

common/src/main/scala/net/psforever/packet/GamePacketOpcode.scala

@@ -553,7 +553,7 @@ object GamePacketOpcode extends Enumeration {
       case VanuModuleUpdateMessage => noDecoder(opcode)
       case FacilityBenefitShieldChargeRequestMessage => noDecoder(opcode)
       case ProximityTerminalUseMessage => noDecoder(opcode)
-      case QuantityDeltaUpdateMessage => noDecoder(opcode)
+      case QuantityDeltaUpdateMessage => game.QuantityDeltaUpdateMessage.decode
       case ChainLashMessage => noDecoder(opcode)
       case ZoneInfoMessage => noDecoder(opcode)
       case LongRangeProjectileInfoMessage => noDecoder(opcode)

common/src/main/scala/net/psforever/packet/game/QuantityDeltaUpdateMessage.scala

@@ -0,0 +1,29 @@
+// Copyright (c) 2016 PSForever.net to present
+package net.psforever.packet.game
+
+import net.psforever.packet.{GamePacketOpcode, Marshallable, PacketHelpers, PlanetSideGamePacket}
+import scodec.Codec
+import scodec.codecs._
+
+/**
+  * Instructs client to update the quantity of an item based on a delta when sent server to client.
+  *
+  * See also [[QuantityUpdateMessage]]
+  *
+  * @param item_guid the item to update
+  * @param quantity_delta the change in quantity of the item
+  */
+final case class QuantityDeltaUpdateMessage(item_guid : PlanetSideGUID,
+                                            quantity_delta : Int)
+  extends PlanetSideGamePacket {
+  type Packet = QuantityDeltaUpdateMessage
+  def opcode = GamePacketOpcode.QuantityDeltaUpdateMessage
+  def encode = QuantityDeltaUpdateMessage.encode(this)
+}
+
+object QuantityDeltaUpdateMessage extends Marshallable[QuantityDeltaUpdateMessage] {
+  implicit val codec : Codec[QuantityDeltaUpdateMessage] = (
+      ("item_guid" | PlanetSideGUID.codec) ::
+        ("quantity_delta" | int32L)
+    ).as[QuantityDeltaUpdateMessage]
+}

common/src/test/scala/GamePacketTest.scala

@@ -858,6 +858,27 @@ class GamePacketTest extends Specification {
       }
     }
 
+    "QuantityDeltaUpdateMessage" should {
+      val string = hex"C4 5300 FBFFFFFF"
+
+      "decode" in {
+        PacketCoding.DecodePacket(string).require match {
+          case QuantityDeltaUpdateMessage(item_guid, quantity) =>
+            item_guid mustEqual PlanetSideGUID(83)
+            quantity mustEqual -5
+          case default =>
+            ko
+        }
+      }
+
+      "encode" in {
+        val msg = QuantityDeltaUpdateMessage(PlanetSideGUID(83), -5)
+        val pkt = PacketCoding.EncodePacket(msg).require.toByteVector
+
+        pkt mustEqual string
+      }
+    }
+
     "PingMsg" should  {
       val packet = hex"1a 00000000 b0360000"