add an event to prevent gun shooting (#17104)

Co-authored-by: deltanedas <@deltanedas:kde.org>

Content.Shared/Weapons/Melee/SharedMeleeWeaponSystem.cs

@@ -16,6 +16,7 @@ using Content.Shared.Popups;
 using Content.Shared.Weapons.Melee.Components;
 using Content.Shared.Weapons.Melee.Events;
 using Content.Shared.Weapons.Ranged.Components;
+using Content.Shared.Weapons.Ranged.Events;
 using Content.Shared.Weapons.Ranged.Systems;
 using Robust.Shared.Audio;
 using Robust.Shared.GameStates;
@@ -71,6 +72,7 @@ public abstract class SharedMeleeWeaponSystem : EntitySystem
         SubscribeLocalEvent<MeleeWeaponComponent, ComponentHandleState>(OnHandleState);
         SubscribeLocalEvent<MeleeWeaponComponent, HandDeselectedEvent>(OnMeleeDropped);
         SubscribeLocalEvent<MeleeWeaponComponent, HandSelectedEvent>(OnMeleeSelected);
+        SubscribeLocalEvent<MeleeWeaponComponent, ShotAttemptedEvent>(OnMeleeShotAttempted);
         SubscribeLocalEvent<MeleeWeaponComponent, GunShotEvent>(OnMeleeShot);
         SubscribeLocalEvent<BonusMeleeDamageComponent, GetMeleeDamageEvent>(OnGetBonusMeleeDamage);
         SubscribeLocalEvent<BonusMeleeDamageComponent, GetHeavyDamageModifierEvent>(OnGetBonusHeavyDamageModifier);
@@ -95,6 +97,12 @@ public abstract class SharedMeleeWeaponSystem : EntitySystem
 #endif
     }
 
+    private void OnMeleeShotAttempted(EntityUid uid, MeleeWeaponComponent comp, ref ShotAttemptedEvent args)
+    {
+        if (comp.NextAttack > Timing.CurTime)
+            args.Cancel();
+    }
+
     private void OnMeleeShot(EntityUid uid, MeleeWeaponComponent component, ref GunShotEvent args)
     {
         if (!TryComp<GunComponent>(uid, out var gun))

Content.Shared/Weapons/Ranged/Events/ShotAttemptedEvent.cs

@@ -0,0 +1,32 @@
+namespace Content.Shared.Weapons.Ranged.Events;
+
+/// <summary>
+/// Raised on a gun when someone is attempting to shoot it.
+/// Cancel this event to prevent it from shooting.
+/// </summary>
+[ByRefEvent]
+public record struct ShotAttemptedEvent
+{
+    /// <summary>
+    /// The user attempting to shoot the gun.
+    /// </summary>
+    public EntityUid User;
+
+    public bool Cancelled { get; private set; }
+
+    /// </summary>
+    /// Prevent the gun from shooting
+    /// </summary>
+    public void Cancel()
+    {
+        Cancelled = true;
+    }
+
+    /// </summary>
+    /// Allow the gun to shoot again, only use if you know what you are doing
+    /// </summary>
+    public void Uncancel()
+    {
+        Cancelled = false;
+    }
+}

Content.Shared/Weapons/Ranged/Systems/SharedGunSystem.cs

@@ -221,8 +221,13 @@ public abstract partial class SharedGunSystem : EntitySystem
 
         var curTime = Timing.CurTime;
 
-        // Maybe Raise an event for this? CanAttack doesn't seem appropriate.
-        if (TryComp<MeleeWeaponComponent>(gunUid, out var melee) && melee.NextAttack > curTime)
+        // check if anything wants to prevent shooting
+        var prevention = new ShotAttemptedEvent
+        {
+            User = user
+        };
+        RaiseLocalEvent(gunUid, ref prevention);
+        if (prevention.Cancelled)
             return;
 
         // Need to do this to play the clicking sound for empty automatic weapons