species restriction for uplink listings (#11185)

Content.Server/Store/Conditions/BuyerSpeciesCondition.cs

@@ -0,0 +1,47 @@
+using Content.Shared.Store;
+using Content.Shared.Species;
+using Content.Shared.CharacterAppearance.Components;
+using Robust.Shared.Serialization.TypeSerializers.Implementations.Custom.Prototype.Set;
+
+namespace Content.Server.Store.Conditions;
+
+/// <summary>
+/// Allows a store entry to be filtered out based on the user's species.
+/// Supports both blacklists and whitelists.
+/// </summary>
+public sealed class BuyerSpeciesCondition : ListingCondition
+{
+    /// <summary>
+    /// A whitelist of species that can purchase this listing.
+    /// </summary>
+    [DataField("whitelist", customTypeSerializer: typeof(PrototypeIdHashSetSerializer<SpeciesPrototype>))]
+    public HashSet<string>? Whitelist;
+
+    /// <summary>
+    /// A blacklist of species that cannot purchase this listing.
+    /// </summary>
+    [DataField("blacklist", customTypeSerializer: typeof(PrototypeIdHashSetSerializer<SpeciesPrototype>))]
+    public HashSet<string>? Blacklist;
+
+    public override bool Condition(ListingConditionArgs args)
+    {
+        var ent = args.EntityManager;
+
+        if (!ent.TryGetComponent<HumanoidAppearanceComponent>(args.Buyer, out var appearance) || appearance.Species == null)
+            return true; // inanimate or non-humanoid entities should be handled elsewhere, main example being surplus crates
+
+        if (Blacklist != null)
+        {
+            if (Blacklist.Contains(appearance.Species))
+                return false;
+        }
+
+        if (Whitelist != null)
+        {
+            if (!Whitelist.Contains(appearance.Species))
+                return false;
+        }
+
+        return true;
+    }
+}