pet dehydrated fish to make him nice to you (#14709)

* petting fish to make him nice to you

* fix fishe, refactor a bit

* fishe

* pro

* feedback, for now

* refactor

* pro

---------

Co-authored-by: deltanedas <@deltanedas:kde.org>

Content.Server/NPC/Components/FactionExceptionComponent.cs

@@ -0,0 +1,17 @@
+using Content.Server.NPC.Systems;
+
+namespace Content.Server.NPC.Components;
+
+/// <summary>
+/// Prevents an NPC from attacking ignored entities from enemy factions.
+/// Can be added to if pettable, see PettableFriendComponent.
+/// </summary>
+[RegisterComponent, Access(typeof(FactionExceptionSystem))]
+public sealed class FactionExceptionComponent : Component
+{
+    /// <summary>
+    /// List of entities that this NPC will refuse to attack
+    /// </summary>
+    [DataField("ignored")]
+    public HashSet<EntityUid> Ignored = new();
+}

Content.Server/NPC/HTN/PrimitiveTasks/Operators/NPCCombatOperator.cs

@@ -1,6 +1,7 @@
 using System.Threading;
 using System.Threading.Tasks;
 using Content.Server.Interaction;
+using Content.Server.NPC.Components;
 using Content.Server.NPC.Pathfinding;
 using Content.Server.NPC.Systems;
 using Content.Shared.Examine;
@@ -8,6 +9,7 @@ using Content.Shared.Interaction;
 using Content.Shared.Mobs;
 using Content.Shared.Mobs.Components;
 using Robust.Shared.Map;
+//using Robust.Shared.Prototypes;
 
 namespace Content.Server.NPC.HTN.PrimitiveTasks.Operators;
 
@@ -15,6 +17,7 @@ public abstract class NPCCombatOperator : HTNOperator
 {
     [Dependency] protected readonly IEntityManager EntManager = default!;
     private FactionSystem _factions = default!;
+    private FactionExceptionSystem _factionException = default!;
     protected InteractionSystem Interaction = default!;
     private PathfindingSystem _pathfinding = default!;
 
@@ -38,6 +41,7 @@ public abstract class NPCCombatOperator : HTNOperator
         base.Initialize(sysManager);
         sysManager.GetEntitySystem<ExamineSystemShared>();
         _factions = sysManager.GetEntitySystem<FactionSystem>();
+        _factionException = sysManager.GetEntitySystem<FactionExceptionSystem>();
         Interaction = sysManager.GetEntitySystem<InteractionSystem>();
         _pathfinding = sysManager.GetEntitySystem<PathfindingSystem>();
     }
@@ -85,6 +89,8 @@ public abstract class NPCCombatOperator : HTNOperator
             paths.Add(UpdateTarget(owner, existingTarget, existingTarget, ownerCoordinates, blackboard, radius, canMove, xformQuery, targets));
         }
 
+        EntManager.TryGetComponent<FactionExceptionComponent>(owner, out var factionException);
+
         // TODO: Need a perception system instead
         // TODO: This will be expensive so will be good to optimise and cut corners.
         foreach (var target in _factions
@@ -93,7 +99,8 @@ public abstract class NPCCombatOperator : HTNOperator
             if (mobQuery.TryGetComponent(target, out var mobState) &&
                 mobState.CurrentState > MobState.Alive ||
                 target == existingTarget ||
-                target == owner)
+                target == owner ||
+                (factionException != null && _factionException.IsIgnored(factionException, target)))
             {
                 continue;
             }

Content.Server/NPC/Systems/FactionExceptionSystem.cs

@@ -0,0 +1,33 @@
+using Content.Server.NPC.Components;
+
+namespace Content.Server.NPC.Systems;
+
+/// <summary>
+/// Prevents an NPC from attacking some entities from an enemy faction.
+/// </summary>
+public sealed class FactionExceptionSystem : EntitySystem
+{
+    /// <summary>
+    /// Returns whether the entity from an enemy faction won't be attacked
+    /// </summary>
+    public bool IsIgnored(FactionExceptionComponent comp, EntityUid target)
+    {
+        return comp.Ignored.Contains(target);
+    }
+
+    /// <summary>
+    /// Prevents an entity from an enemy faction from being attacked
+    /// </summary>
+    public void IgnoreEntity(FactionExceptionComponent comp, EntityUid target)
+    {
+        comp.Ignored.Add(target);
+    }
+
+    /// <summary>
+    /// Prevents a list of entities from an enemy faction from being attacked
+    /// </summary>
+    public void IgnoreEntities(FactionExceptionComponent comp, IEnumerable<EntityUid> ignored)
+    {
+        comp.Ignored.UnionWith(ignored);
+    }
+}