NPC refactor (#10122)

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

Content.Server/NPC/Components/NPCMeleeCombatComponent.cs

@@ -0,0 +1,47 @@
+namespace Content.Server.NPC.Components;
+
+/// <summary>
+/// Added to NPCs whenever they're in melee combat so they can be handled by the dedicated system.
+/// </summary>
+[RegisterComponent]
+public sealed class NPCMeleeCombatComponent : Component
+{
+    /// <summary>
+    /// Weapon we're using to attack the target. Can also be ourselves.
+    /// </summary>
+    [ViewVariables] public EntityUid Weapon;
+
+    [ViewVariables]
+    public EntityUid Target;
+
+    [ViewVariables]
+    public CombatStatus Status = CombatStatus.Normal;
+}
+
+public enum CombatStatus : byte
+{
+    /// <summary>
+    /// The target isn't in LOS anymore.
+    /// </summary>
+    NotInSight,
+
+    /// <summary>
+    /// Due to some generic reason we are unable to attack the target.
+    /// </summary>
+    Unspecified,
+
+    /// <summary>
+    /// Set if we can't reach the target for whatever reason.
+    /// </summary>
+    TargetUnreachable,
+
+    /// <summary>
+    /// Set if the weapon we were assigned is no longer valid.
+    /// </summary>
+    NoWeapon,
+
+    /// <summary>
+    /// No dramas.
+    /// </summary>
+    Normal,
+}