Add mob retaliation (#19901)

Content.Server/NPC/Systems/NpcFactionSystem.Exception.cs

@@ -0,0 +1,130 @@
+using System.Linq;
+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 partial class NpcFactionSystem
+{
+    private EntityQuery<FactionExceptionComponent> _exceptionQuery;
+    private EntityQuery<FactionExceptionTrackerComponent> _trackerQuery;
+
+    public void InitializeException()
+    {
+        _exceptionQuery = GetEntityQuery<FactionExceptionComponent>();
+        _trackerQuery = GetEntityQuery<FactionExceptionTrackerComponent>();
+
+        SubscribeLocalEvent<FactionExceptionComponent, ComponentShutdown>(OnShutdown);
+        SubscribeLocalEvent<FactionExceptionTrackerComponent, ComponentShutdown>(OnTrackerShutdown);
+    }
+
+    private void OnShutdown(EntityUid uid, FactionExceptionComponent component, ComponentShutdown args)
+    {
+        foreach (var ent in component.Hostiles)
+        {
+            if (!_trackerQuery.TryGetComponent(ent, out var trackerComponent))
+                continue;
+            trackerComponent.Entities.Remove(uid);
+        }
+
+        foreach (var ent in component.Ignored)
+        {
+            if (!_trackerQuery.TryGetComponent(ent, out var trackerComponent))
+                continue;
+            trackerComponent.Entities.Remove(uid);
+        }
+    }
+
+    private void OnTrackerShutdown(EntityUid uid, FactionExceptionTrackerComponent component, ComponentShutdown args)
+    {
+        foreach (var ent in component.Entities)
+        {
+            if (!_exceptionQuery.TryGetComponent(ent, out var exceptionComponent))
+                continue;
+            exceptionComponent.Ignored.Remove(uid);
+            exceptionComponent.Hostiles.Remove(uid);
+        }
+    }
+
+    /// <summary>
+    /// Returns whether the entity from an enemy faction won't be attacked
+    /// </summary>
+    public bool IsIgnored(EntityUid uid, EntityUid target, FactionExceptionComponent? comp = null)
+    {
+        if (!Resolve(uid, ref comp, false))
+            return false;
+
+        return comp.Ignored.Contains(target);
+    }
+
+    /// <summary>
+    /// Returns the specific hostile entities for a given entity.
+    /// </summary>
+    public IEnumerable<EntityUid> GetHostiles(EntityUid uid, FactionExceptionComponent? comp = null)
+    {
+        if (!Resolve(uid, ref comp, false))
+            return Array.Empty<EntityUid>();
+
+        return comp.Hostiles;
+    }
+
+    /// <summary>
+    /// Prevents an entity from an enemy faction from being attacked
+    /// </summary>
+    public void IgnoreEntity(EntityUid uid, EntityUid target, FactionExceptionComponent? comp = null)
+    {
+        comp ??= EnsureComp<FactionExceptionComponent>(uid);
+        comp.Ignored.Add(target);
+        EnsureComp<FactionExceptionTrackerComponent>(target).Entities.Add(uid);
+    }
+
+    /// <summary>
+    /// Prevents a list of entities from an enemy faction from being attacked
+    /// </summary>
+    public void IgnoreEntities(EntityUid uid, IEnumerable<EntityUid> ignored, FactionExceptionComponent? comp = null)
+    {
+        comp ??= EnsureComp<FactionExceptionComponent>(uid);
+        foreach (var ignore in ignored)
+        {
+            IgnoreEntity(uid, ignore, comp);
+        }
+    }
+
+    /// <summary>
+    /// Makes an entity always be considered hostile.
+    /// </summary>
+    public void AggroEntity(EntityUid uid, EntityUid target, FactionExceptionComponent? comp = null)
+    {
+        comp ??= EnsureComp<FactionExceptionComponent>(uid);
+        comp.Hostiles.Add(target);
+        EnsureComp<FactionExceptionTrackerComponent>(target).Entities.Add(uid);
+    }
+
+    /// <summary>
+    /// Makes an entity no longer be considered hostile, if it was.
+    /// Doesn't apply to regular faction hostilities.
+    /// </summary>
+    public void DeAggroEntity(EntityUid uid, EntityUid target, FactionExceptionComponent? comp = null)
+    {
+        if (!Resolve(uid, ref comp, false))
+            return;
+        if (!comp.Hostiles.Remove(target) || !_trackerQuery.TryGetComponent(target, out var tracker))
+            return;
+        tracker.Entities.Remove(uid);
+    }
+
+    /// <summary>
+    /// Makes a list of entities no longer be considered hostile, if it was.
+    /// Doesn't apply to regular faction hostilities.
+    /// </summary>
+    public void AggroEntities(EntityUid uid, IEnumerable<EntityUid> entities, FactionExceptionComponent? comp = null)
+    {
+        comp ??= EnsureComp<FactionExceptionComponent>(uid);
+        foreach (var ent in entities)
+        {
+            AggroEntity(uid, ent, comp);
+        }
+    }
+}