(mostly) ECS projectiles (#4317)

* (mostly) ECS projectiles

* a

* Actual queue

Content.Server/Projectiles/ProjectileSystem.cs

@@ -1,17 +1,70 @@
+using Content.Server.Camera;
 using Content.Server.Projectiles.Components;
+using Content.Shared.Damage.Components;
 using JetBrains.Annotations;
+using Robust.Shared.Audio;
 using Robust.Shared.GameObjects;
+using Robust.Shared.Physics.Dynamics;
+using Robust.Shared.Player;
 
 namespace Content.Server.Projectiles
 {
     [UsedImplicitly]
     internal sealed class ProjectileSystem : EntitySystem
     {
+        public override void Initialize()
+        {
+            base.Initialize();
+            SubscribeLocalEvent<ProjectileComponent, StartCollideEvent>(HandleCollide);
+        }
+
+        private void HandleCollide(EntityUid uid, ProjectileComponent component, StartCollideEvent args)
+        {
+            // This is so entities that shouldn't get a collision are ignored.
+            if (!args.OtherFixture.Hard || component.DamagedEntity)
+            {
+                return;
+            }
+
+            var coordinates = args.OtherFixture.Body.Owner.Transform.Coordinates;
+            var playerFilter = Filter.Pvs(coordinates);
+            if (args.OtherFixture.Body.Owner.TryGetComponent(out IDamageableComponent? damage) && component.SoundHitSpecies != null)
+            {
+                SoundSystem.Play(playerFilter, component.SoundHitSpecies, coordinates);
+            }
+            else if (component.SoundHit != null)
+            {
+                SoundSystem.Play(playerFilter, component.SoundHit, coordinates);
+            }
+
+            if (damage != null)
+            {
+                EntityManager.TryGetEntity(component.Shooter, out var shooter);
+
+                foreach (var (damageType, amount) in component.Damages)
+                {
+                    damage.ChangeDamage(damageType, amount, false, shooter);
+                }
+
+                component.DamagedEntity = true;
+            }
+
+            // Damaging it can delete it
+            if (!args.OtherFixture.Body.Deleted && args.OtherFixture.Body.Owner.TryGetComponent(out CameraRecoilComponent? recoilComponent))
+            {
+                var direction = args.OurFixture.Body.LinearVelocity.Normalized;
+                recoilComponent.Kick(direction);
+            }
+
+            if (component.DeleteOnCollide)
+                EntityManager.QueueDeleteEntity(uid);
+        }
+
         public override void Update(float frameTime)
         {
             base.Update(frameTime);
 
-            foreach (var component in ComponentManager.EntityQuery<ProjectileComponent>(true))
+            foreach (var component in ComponentManager.EntityQuery<ProjectileComponent>())
             {
                 component.TimeLeft -= frameTime;