Trait Modify Factions (#955)

# Description

Made by request from Nuclear14, while also adding a trait that was
present both in Parkstation, as well as something N14 would like to
have. This PR extends the TraitSystem so that it can now also add or
remove Factions from a character. It also adds in the Animal Friend
trait from Parkstation/Fallout: New Vegas.

# Changelog

:cl:
- add: The Animal Friend trait has been added to the game. Characters
with this trait are not attacked by animals.

---------

Signed-off-by: VMSolidus <[email protected]>
Co-authored-by: DEATHB4DEFEAT <[email protected]>

Content.Server/Traits/TraitSystem.cs

@@ -14,6 +14,7 @@
 using Content.Shared.Psionics;
 using Content.Server.Language;
 using Content.Shared.Mood;
+using Content.Server.NPC.Systems;
 
 namespace Content.Server.Traits;
 
@@ -28,6 +29,7 @@ public sealed class TraitSystem : EntitySystem
     [Dependency] private readonly PsionicAbilitiesSystem _psionicAbilities = default!;
     [Dependency] private readonly IComponentFactory _componentFactory = default!;
     [Dependency] private readonly LanguageSystem _languageSystem = default!;
+    [Dependency] private readonly NpcFactionSystem _factionSystem = default!;
 
     public override void Initialize()
     {
@@ -71,6 +73,8 @@ public void AddTrait(EntityUid uid, TraitPrototype traitPrototype)
         AddTraitLanguage(uid, traitPrototype);
         RemoveTraitLanguage(uid, traitPrototype);
         AddTraitMoodlets(uid, traitPrototype);
+        RemoveTraitFactions(uid, traitPrototype);
+        AddTraitFactions(uid, traitPrototype);
     }
 
     /// <summary>
@@ -225,4 +229,28 @@ public void AddTraitMoodlets(EntityUid uid, TraitPrototype traitPrototype)
             if (_prototype.TryIndex(moodProto, out var moodlet))
                 RaiseLocalEvent(uid, new MoodEffectEvent(moodlet.ID));
     }
+
+    /// <summary>
+    ///     If a trait includes any faction removals, this removes the faction from the receiving entity.
+    /// </summary>
+    public void RemoveTraitFactions(EntityUid uid, TraitPrototype traitPrototype)
+    {
+        if (traitPrototype.RemoveFactions is null)
+            return;
+
+        foreach (var faction in traitPrototype.RemoveFactions)
+            _factionSystem.RemoveFaction(uid, faction);
+    }
+
+    /// <summary>
+    ///     If a trait includes any factions to add, this adds the factions to the receiving entity.
+    /// </summary>
+    public void AddTraitFactions(EntityUid uid, TraitPrototype traitPrototype)
+    {
+        if (traitPrototype.AddFactions is null)
+            return;
+
+        foreach (var faction in traitPrototype.AddFactions)
+            _factionSystem.AddFaction(uid, faction);
+    }
 }

Content.Shared/Traits/Prototypes/TraitPrototype.cs

@@ -87,4 +87,22 @@ public sealed partial class TraitPrototype : IPrototype
     /// </summary>
     [DataField]
     public List<ProtoId<MoodEffectPrototype>>? MoodEffects { get; private set; } = default!;
+
+    /// <summary>
+    ///     The list of all Factions that this trait removes.
+    /// </summary>
+    /// <remarks>
+    ///     I can't actually Validate these because the proto lives in Shared.
+    /// </remarks>
+    [DataField]
+    public List<string>? RemoveFactions { get; private set; } = default!;
+
+    /// <summary>
+    ///     The list of all Factions that this trait adds.
+    /// </summary>
+    /// <remarks>
+    ///     I can't actually Validate these because the proto lives in Shared.
+    /// </remarks>
+    [DataField]
+    public List<string>? AddFactions { get; private set; } = default!;
 }

Resources/Locale/en-US/traits/traits.ftl

@@ -318,6 +318,10 @@ trait-name-AddictionNicotine = Nicotine Addiction
 trait-description-AddictionNicotine =
     You have an addiction to Nicotine, and will require frequent smoke breaks to keep your mood in check.
 
+trait-name-AnimalFriend = Animal Friend
+trait-description-AnimalFriend =
+    You have a way with animals. You will never be attacked by animals, unless you attack them first.
+    
 trait-name-Liar = Pathological liar
 trait-description-Liar = You can hardly bring yourself to tell the truth. Sometimes you lie anyway.
 

Resources/Prototypes/Traits/skills.yml

@@ -297,8 +297,13 @@
   componentRemovals:
     - PsionicInsulation
   requirements:
-    - !type:CharacterLogicOrRequirement
-      requirements:
-        - !type:CharacterSpeciesRequirement
-          species:
-            - IPC
+    - !type:CharacterSpeciesRequirement
+      species:
+        - IPC
+
+- type: trait
+  id: AnimalFriend
+  category: Mental
+  points: -4
+  addFactions:
+    - AnimalFriend

Resources/Prototypes/ai_factions.yml

@@ -35,6 +35,8 @@
 
 - type: npcFaction
   id: SimpleHostile
+  friendly:
+  - AnimalFriend
   hostile:
   - NanoTrasen
   - Syndicate
@@ -86,6 +88,8 @@
 
 - type: npcFaction
   id: Pibble
+  friendly:
+  - AnimalFriend
   hostile:
   - Cat
   - Birb
@@ -99,3 +103,6 @@
 
 - type: npcFaction
   id: Birb
+
+- type: npcFaction
+  id: AnimalFriend