CatStation/Content.Shared/Disposal/Mailing/SharedMailingUnitSystem.cs

using Content.Shared.Configurable;
using Content.Shared.DeviceNetwork.Components;
using Content.Shared.DeviceNetwork.Events;
using Content.Shared.DeviceNetwork.Systems;
using Content.Shared.Disposal.Components;
using Content.Shared.Disposal.Unit;
using Content.Shared.Interaction;
using Robust.Shared.Player;

namespace Content.Shared.Disposal.Mailing;

public abstract partial class SharedMailingUnitSystem : EntitySystem
{
    [Dependency] private SharedDeviceNetworkSystem _deviceNetwork = default!;
    [Dependency] private SharedUserInterfaceSystem _userInterface = default!;

    private const string MailTag = "mail";
    private const string TagConfigurationKey = "tag";

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

        SubscribeLocalEvent<MailingUnitComponent, ComponentInit>(OnComponentInit);
        SubscribeLocalEvent<MailingUnitComponent, BeforeDisposalFlushEvent>(OnBeforeFlush);
        SubscribeLocalEvent<MailingUnitComponent, ConfigurationUpdatedEvent>(OnConfigurationUpdated);
        SubscribeLocalEvent<MailingUnitComponent, ActivateInWorldEvent>(HandleActivate, before: new[] { typeof(SharedDisposalUnitSystem) });
        SubscribeLocalEvent<MailingUnitComponent, TargetSelectedMessage>(OnTargetSelected);
    }

    private void OnComponentInit(Entity<MailingUnitComponent> ent, ref ComponentInit args)
    {
        UpdateTargetList(ent);
    }

    [SubscribeLocalEvent]
    private void OnRequestTag(Entity<MailingUnitComponent> ent, ref DeviceNetworkPacketEvent<MailRequestTagPayload> args)
    {
        if (ent.Comp.Tag == null)
            return;

        var tagPayload = new MailTagPayload
        {
            Tag = ent.Comp.Tag,
        };

        _deviceNetwork.SendPacket(ent.Owner, args.SenderAddress, ref tagPayload, args.Frequency);
    }

    [SubscribeLocalEvent]
    private void OnTag(Entity<MailingUnitComponent> ent, ref DeviceNetworkPacketEvent<MailTagPayload> args)
    {
        ent.Comp.TargetList.Add(args.Data.Tag);
        Dirty(ent);
    }

    /// <summary>
    /// Prevents the unit from flushing if no target is selected
    /// </summary>
    private void OnBeforeFlush(Entity<MailingUnitComponent> ent, ref BeforeDisposalFlushEvent args)
    {
        if (string.IsNullOrEmpty(ent.Comp.Target))
        {
            args.Cancel();
            return;
        }

        Dirty(ent);
        args.Tags.Add(MailTag);
        args.Tags.Add(ent.Comp.Target);

        BroadcastSentMessage(ent);
    }

    /// <summary>
    /// Broadcast that a mail was sent including the src and target tags
    /// </summary>
    private void BroadcastSentMessage(Entity<MailingUnitComponent> ent, DeviceNetworkComponent? device = null)
    {
        if (string.IsNullOrEmpty(ent.Comp.Tag) || string.IsNullOrEmpty(ent.Comp.Target) || !Resolve(ent, ref device))
            return;

        var payload = new MailSendPayload
        {
            Tag = ent.Comp.Tag,
            Target = ent.Comp.Target,
        };

        _deviceNetwork.SendPacket((ent.Owner, device), null, ref payload);
    }

    /// <summary>
    /// Clears the units target list and broadcasts a <see cref="MailRequestTagPayload"/>.
    /// The target list will then get populated with <see cref="MailTagPayload"/> responses from all active mailing units on the same grid
    /// </summary>
    private void UpdateTargetList(Entity<MailingUnitComponent> ent, DeviceNetworkComponent? device = null)
    {
        if (!Resolve(ent, ref device, false))
            return;

        var payload = new MailRequestTagPayload();
        ent.Comp.TargetList.Clear();
        _deviceNetwork.SendPacket((ent.Owner, device), null, ref payload);
    }

    /// <summary>
    /// Gets called when the units tag got updated
    /// </summary>
    private void OnConfigurationUpdated(Entity<MailingUnitComponent> ent, ref ConfigurationUpdatedEvent args)
    {
        var configuration = args.Configuration.Config;
        if (!configuration.ContainsKey(TagConfigurationKey) || configuration[TagConfigurationKey] == string.Empty)
        {
            ent.Comp.Tag = null;
            return;
        }

        ent.Comp.Tag = configuration[TagConfigurationKey];
        Dirty(ent);
    }

    private void HandleActivate(Entity<MailingUnitComponent> ent, ref ActivateInWorldEvent args)
    {
        if (args.Handled || !args.Complex)
            return;

        if (!TryComp(args.User, out ActorComponent? actor))
            return;

        args.Handled = true;
        UpdateTargetList(ent);

        _userInterface.OpenUi(ent.Owner, MailingUnitUiKey.Key, actor.PlayerSession);
    }

    private void OnTargetSelected(Entity<MailingUnitComponent> ent, ref TargetSelectedMessage args)
    {
        ent.Comp.Target = args.Target;
        Dirty(ent);

        if (_userInterface.TryGetOpenUi(ent.Owner, MailingUnitUiKey.Key, out var bui))
        {
            bui.Update<MailingUnitBoundUserInterfaceState>();
        }
    }
}