NPC refactor (#10122)

Co-authored-by: metalgearsloth <metalgearsloth@gmail.com>

Content.Server/NPC/HTN/Preconditions/TargetInLOSPrecondition.cs

@@ -0,0 +1,32 @@
+using Content.Server.Interaction;
+
+namespace Content.Server.NPC.HTN.Preconditions;
+
+public sealed class TargetInLOSPrecondition : HTNPrecondition
+{
+    private InteractionSystem _interaction = default!;
+
+    [ViewVariables, DataField("targetKey")]
+    public string TargetKey = "CombatTarget";
+
+    [ViewVariables, DataField("rangeKey")]
+    public string RangeKey = "RangeKey";
+
+    public override void Initialize(IEntitySystemManager sysManager)
+    {
+        base.Initialize(sysManager);
+        _interaction = sysManager.GetEntitySystem<InteractionSystem>();
+    }
+
+    public override bool IsMet(NPCBlackboard blackboard)
+    {
+        var owner = blackboard.GetValue<EntityUid>(NPCBlackboard.Owner);
+
+        if (!blackboard.TryGetValue<EntityUid>(TargetKey, out var target))
+            return false;
+
+        var range = blackboard.GetValueOrDefault<float>(RangeKey);
+
+        return _interaction.InRangeUnobstructed(owner, target, range);
+    }
+}