Core/Scripts: unified scripted gossip/quest api

Port From (https://github.com/TrinityCore/TrinityCore/commit/6604849716bc73d82a4cdbf8c66bb188086ceae4)

Source/Game/AI/CoreAI/UnitAI.cs

@@ -378,15 +378,39 @@ namespace Game.AI
         public virtual void HealDone(Unit to, uint addhealth) { }
         public virtual void SpellInterrupted(uint spellId, uint unTimeMs) {}
 
-        public virtual void GossipHello(Player player) { }
-        public virtual void GossipSelect(Player player, uint menuId, uint gossipListId) { }
-        public virtual void GossipSelectCode(Player player, uint menuId, uint gossipListId, string code) { }
+        /// <summary>
+        /// Called when a player opens a gossip dialog with the creature.
+        /// </summary>
+        public virtual bool GossipHello(Player player) { return false; }
+
+        /// <summary>
+        /// Called when a player selects a gossip item in the creature's gossip menu.
+        /// </summary>
+        public virtual bool GossipSelect(Player player, uint menuId, uint gossipListId) { return false; }
+
+        /// <summary>
+        /// Called when a player selects a gossip with a code in the creature's gossip menu.
+        /// </summary>
+        public virtual bool GossipSelectCode(Player player, uint menuId, uint gossipListId, string code) { return false; }
+
+        /// <summary>
+        /// Called when a player accepts a quest from the creature.
+        /// </summary>
         public virtual void QuestAccept(Player player, Quest quest) { }
-        public virtual void QuestSelect(Player player, Quest quest) { }
-        public virtual void QuestComplete(Player player, Quest quest) { }
+
+        /// <summary>
+        /// Called when a player completes a quest and is rewarded, opt is the selected item's index or 0
+        /// </summary>
         public virtual void QuestReward(Player player, Quest quest, uint opt) { }
+
+        /// <summary>
+        /// Called when a game event starts or ends
+        /// </summary>
         public virtual void OnGameEvent(bool start, ushort eventId) { }
 
+        // Called when the dialog status between a player and the creature is requested.
+        public virtual QuestGiverStatus GetDialogStatus(Player player) { return QuestGiverStatus.ScriptedNoStatus; }
+
         public static AISpellInfoType[] AISpellInfo;
 
         protected Unit me { get; private set; }