tbd-station-14/Content.Server/Animals/Systems/UdderSystem.cs

using Content.Server.Animals.Components;
using Content.Server.Chemistry.Components.SolutionManager;
using Content.Server.Chemistry.EntitySystems;
using Content.Server.DoAfter;
using Content.Server.Nutrition.Components;
using Content.Server.Popups;
using Content.Shared.Chemistry.Components;
using Content.Shared.DoAfter;
using Content.Shared.IdentityManagement;
using Content.Shared.Nutrition.Components;
using Content.Shared.Nutrition.EntitySystems;
using Content.Shared.Popups;
using Content.Shared.Udder;
using Content.Shared.Verbs;

namespace Content.Server.Animals.Systems
{
    /// <summary>
    ///     Gives ability to living beings with acceptable hunger level to produce milkable reagents.
    /// </summary>
    internal sealed class UdderSystem : EntitySystem
    {
        [Dependency] private readonly SolutionContainerSystem _solutionContainerSystem = default!;
        [Dependency] private readonly HungerSystem _hunger = default!;
        [Dependency] private readonly SharedDoAfterSystem _doAfterSystem = default!;
        [Dependency] private readonly PopupSystem _popupSystem = default!;

        public override void Initialize()
        {
            base.Initialize();

            SubscribeLocalEvent<UdderComponent, GetVerbsEvent<AlternativeVerb>>(AddMilkVerb);
            SubscribeLocalEvent<UdderComponent, MilkingDoAfterEvent>(OnDoAfter);
        }
        public override void Update(float frameTime)
        {
            foreach (var udder in EntityManager.EntityQuery<UdderComponent>(false))
            {
                udder.AccumulatedFrameTime += frameTime;

                while (udder.AccumulatedFrameTime > udder.UpdateRate)
                {
                    udder.AccumulatedFrameTime -= udder.UpdateRate;

                    // Actually there is food digestion so no problem with instant reagent generation "OnFeed"
                    if (EntityManager.TryGetComponent(udder.Owner, out HungerComponent? hunger))
                    {
                        // Is there enough nutrition to produce reagent?
                        if (_hunger.GetHungerThreshold(hunger) < HungerThreshold.Peckish)
                            continue;
                    }

                    if (!_solutionContainerSystem.TryGetSolution(udder.Owner, udder.TargetSolutionName,
                            out var solution))
                        continue;

                    //TODO: toxins from bloodstream !?
                    _solutionContainerSystem.TryAddReagent(udder.Owner, solution, udder.ReagentId,
                        udder.QuantityPerUpdate, out var accepted);
                }
            }
        }

        private void AttemptMilk(EntityUid uid, EntityUid userUid, EntityUid containerUid, UdderComponent? udder = null)
        {
            if (!Resolve(uid, ref udder))
                return;

            var doargs = new DoAfterArgs(EntityManager, userUid, 5, new MilkingDoAfterEvent(), uid, uid, used: containerUid)
            {
                BreakOnUserMove = true,
                BreakOnDamage = true,
                BreakOnTargetMove = true,
                MovementThreshold = 1.0f,
            };

            _doAfterSystem.TryStartDoAfter(doargs);
        }

        private void OnDoAfter(EntityUid uid, UdderComponent component, MilkingDoAfterEvent args)
        {
            if (args.Cancelled || args.Handled || args.Args.Used == null)
                return;

            if (!_solutionContainerSystem.TryGetSolution(uid, component.TargetSolutionName, out var solution))
                return;

            if (!_solutionContainerSystem.TryGetRefillableSolution(args.Args.Used.Value, out var targetSolution))
                return;

            args.Handled = true;
            var quantity = solution.Volume;
            if(quantity == 0)
            {
                _popupSystem.PopupEntity(Loc.GetString("udder-system-dry"), uid, args.Args.User);
                return;
            }

            if (quantity > targetSolution.AvailableVolume)
                quantity = targetSolution.AvailableVolume;

            var split = _solutionContainerSystem.SplitSolution(uid, solution, quantity);
            _solutionContainerSystem.TryAddSolution(args.Args.Used.Value, targetSolution, split);

            _popupSystem.PopupEntity(Loc.GetString("udder-system-success", ("amount", quantity), ("target", Identity.Entity(args.Args.Used.Value, EntityManager))), uid,
                args.Args.User, PopupType.Medium);
        }

        private void AddMilkVerb(EntityUid uid, UdderComponent component, GetVerbsEvent<AlternativeVerb> args)
        {
            if (args.Using == null ||
                 !args.CanInteract ||
                 !EntityManager.HasComponent<RefillableSolutionComponent>(args.Using.Value))
                return;

            AlternativeVerb verb = new()
            {
                Act = () =>
                {
                    AttemptMilk(uid, args.User, args.Using.Value, component);
                },
                Text = Loc.GetString("udder-system-verb-milk"),
                Priority = 2
            };
            args.Verbs.Add(verb);
        }
    }
}