tbd-station-14/Content.Server/Storage/EntitySystems/StorageSystem.cs

using System.Collections.Generic;
using Content.Server.Hands.Components;
using Content.Server.Interaction;
using Content.Server.Storage.Components;
using Content.Shared.Movement;
using JetBrains.Annotations;
using Robust.Server.Player;
using Robust.Shared.Containers;
using Robust.Shared.GameObjects;
using Robust.Shared.IoC;
using Robust.Shared.Timing;

namespace Content.Server.Storage.EntitySystems
{
    [UsedImplicitly]
    internal sealed class StorageSystem : EntitySystem
    {
        [Dependency] private readonly IGameTiming _gameTiming = default!;

        private readonly List<IPlayerSession> _sessionCache = new();

        /// <inheritdoc />
        public override void Initialize()
        {
            base.Initialize();

            SubscribeLocalEvent<EntRemovedFromContainerMessage>(HandleEntityRemovedFromContainer);
            SubscribeLocalEvent<EntInsertedIntoContainerMessage>(HandleEntityInsertedIntoContainer);
            SubscribeLocalEvent<EntityStorageComponent, RelayMovementEntityEvent>(OnRelayMovement);
        }

        private void OnRelayMovement(EntityUid uid, EntityStorageComponent component, RelayMovementEntityEvent args)
        {
            if (EntityManager.HasComponent<HandsComponent>(uid))
            {
                if (_gameTiming.CurTime <
                    component.LastInternalOpenAttempt + EntityStorageComponent.InternalOpenAttemptDelay)
                {
                    return;
                }

                component.LastInternalOpenAttempt = _gameTiming.CurTime;
                component.TryOpenStorage(args.Entity);
            }
        }

        /// <inheritdoc />
        public override void Update(float frameTime)
        {
            foreach (var component in EntityManager.EntityQuery<ServerStorageComponent>(true))
            {
                CheckSubscribedEntities(component);
            }
        }

        private static void HandleEntityRemovedFromContainer(EntRemovedFromContainerMessage message)
        {
            var oldParentEntity = message.Container.Owner;

            if (oldParentEntity.TryGetComponent(out ServerStorageComponent? storageComp))
            {
                storageComp.HandleEntityMaybeRemoved(message);
            }
        }

        private static void HandleEntityInsertedIntoContainer(EntInsertedIntoContainerMessage message)
        {
            var oldParentEntity = message.Container.Owner;

            if (oldParentEntity.TryGetComponent(out ServerStorageComponent? storageComp))
            {
                storageComp.HandleEntityMaybeInserted(message);
            }
        }

        private void CheckSubscribedEntities(ServerStorageComponent storageComp)
        {

            // We have to cache the set of sessions because Unsubscribe modifies the original.
            _sessionCache.Clear();
            _sessionCache.AddRange(storageComp.SubscribedSessions);

            if (_sessionCache.Count == 0)
                return;

            var storagePos = storageComp.Owner.Transform.WorldPosition;
            var storageMap = storageComp.Owner.Transform.MapID;

            foreach (var session in _sessionCache)
            {
                var attachedEntity = session.AttachedEntity;

                // The component manages the set of sessions, so this invalid session should be removed soon.
                if (attachedEntity == null || !attachedEntity.IsValid())
                    continue;

                if (storageMap != attachedEntity.Transform.MapID)
                    continue;

                var distanceSquared = (storagePos - attachedEntity.Transform.WorldPosition).LengthSquared;
                if (distanceSquared > InteractionSystem.InteractionRangeSquared)
                {
                    storageComp.UnsubscribeSession(session);
                }
            }
        }
    }
}