smoke grenades (#20996)

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

Content.Server/Explosion/Components/OnTrigger/SmokeOnTriggerComponent.cs

@@ -0,0 +1,41 @@
+using Content.Server.Explosion.EntitySystems;
+using Content.Shared.Chemistry.Components;
+using Robust.Shared.Prototypes;
+
+namespace Content.Server.Explosion.Components;
+
+/// <summary>
+/// Creates a smoke cloud when triggered, with an optional solution to include in it.
+/// No sound is played incase a grenade is stealthy, use <see cref="SoundOnTriggerComponent"/> if you want a sound.
+/// </summary>
+[RegisterComponent, Access(typeof(SmokeOnTriggerSystem))]
+public sealed partial class SmokeOnTriggerComponent : Component
+{
+    /// <summary>
+    /// How long the smoke stays for, after it has spread.
+    /// </summary>
+    [DataField, ViewVariables(VVAccess.ReadWrite)]
+    public float Duration = 10;
+
+    /// <summary>
+    /// How much the smoke will spread.
+    /// </summary>
+    [DataField(required: true), ViewVariables(VVAccess.ReadWrite)]
+    public int SpreadAmount;
+
+    /// <summary>
+    /// Smoke entity to spawn.
+    /// Defaults to smoke but you can use foam if you want.
+    /// </summary>
+    [DataField, ViewVariables(VVAccess.ReadWrite)]
+    public ProtoId<EntityPrototype> SmokePrototype = "Smoke";
+
+    /// <summary>
+    /// Solution to add to each smoke cloud.
+    /// </summary>
+    /// <remarks>
+    /// When using repeating trigger this essentially gets multiplied so dont do anything crazy like omnizine or lexorin.
+    /// </remarks>
+    [DataField, ViewVariables(VVAccess.ReadWrite)]
+    public Solution Solution = new();
+}

Content.Server/Explosion/EntitySystems/SmokeOnTriggerSystem.cs

@@ -0,0 +1,46 @@
+using Content.Server.Explosion.Components;
+using Content.Server.Fluids.EntitySystems;
+using Content.Shared.Chemistry.Components;
+using Content.Shared.Coordinates.Helpers;
+using Content.Shared.Maps;
+using Robust.Shared.Map;
+
+namespace Content.Server.Explosion.EntitySystems;
+
+/// <summary>
+/// Handles creating smoke when <see cref="SmokeOnTriggerComponent"/> is triggered.
+/// </summary>
+public sealed class SmokeOnTriggerSystem : EntitySystem
+{
+    [Dependency] private readonly IMapManager _mapMan = default!;
+    [Dependency] private readonly SmokeSystem _smoke = default!;
+
+    public override void Initialize()
+    {
+        base.Initialize();
+
+        SubscribeLocalEvent<SmokeOnTriggerComponent, TriggerEvent>(OnTrigger);
+    }
+
+    private void OnTrigger(EntityUid uid, SmokeOnTriggerComponent comp, TriggerEvent args)
+    {
+        var xform = Transform(uid);
+        if (!_mapMan.TryFindGridAt(xform.MapPosition, out _, out var grid) ||
+            !grid.TryGetTileRef(xform.Coordinates, out var tileRef) ||
+            tileRef.Tile.IsSpace())
+        {
+            return;
+        }
+
+        var coords = grid.MapToGrid(xform.MapPosition);
+        var ent = Spawn(comp.SmokePrototype, coords.SnapToGrid());
+        if (!TryComp<SmokeComponent>(ent, out var smoke))
+        {
+            Logger.Error($"Smoke prototype {comp.SmokePrototype} was missing SmokeComponent");
+            Del(ent);
+            return;
+        }
+
+        _smoke.StartSmoke(ent, comp.Solution, comp.Duration, comp.SpreadAmount, smoke);
+    }
+}