CatStation/Content.Shared/Changeling/Systems/ChangelingDevourSystem.cs

using Content.Shared.Actions;
using Content.Shared.Administration.Logs;
using Content.Shared.Armor;
using Content.Shared.Atmos.Rotting;
using Content.Shared.Body.Components;
using Content.Shared.Body.Systems;
using Content.Shared.Changeling.Components;
using Content.Shared.Store;
using Content.Shared.Damage.Systems;
using Content.Shared.Database;
using Content.Shared.DoAfter;
using Content.Shared.Fluids;
using Content.Shared.Humanoid;
using Content.Shared.IdentityManagement;
using Content.Shared.Inventory;
using Content.Shared.Mobs.Systems;
using Content.Shared.Popups;
using Content.Shared.Store.Components;
using Content.Shared.Whitelist;
using Content.Shared.Zombies;
using Robust.Shared.Audio.Systems;
using Robust.Shared.Network;

namespace Content.Shared.Changeling.Systems;

public sealed partial class ChangelingDevourSystem : EntitySystem
{
    [Dependency] private BloodstreamSystem _bloodstream = default!;
    [Dependency] private DamageableSystem _damageable = default!;
    [Dependency] private EntityWhitelistSystem _whitelistSystem = default!;
    [Dependency] private INetManager _net = default!;
    [Dependency] private ISharedAdminLogManager _adminLogger = default!;
    [Dependency] private MobStateSystem _mobState = default!;
    [Dependency] private SharedActionsSystem _actionsSystem = default!;
    [Dependency] private SharedAudioSystem _audio = default!;
    [Dependency] private SharedChangelingIdentitySystem _changelingIdentity = default!;
    [Dependency] private SharedDoAfterSystem _doAfterSystem = default!;
    [Dependency] private SharedPopupSystem _popupSystem = default!;
    [Dependency] private SharedStoreSystem _store = default!;
    [Dependency] private SharedPuddleSystem _puddle = default!;

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

        SubscribeLocalEvent<ChangelingDevourComponent, MapInitEvent>(OnMapInit);
        SubscribeLocalEvent<ChangelingDevourComponent, ChangelingDevourActionEvent>(OnDevourAction);
        SubscribeLocalEvent<ChangelingDevourComponent, ChangelingDevourWindupDoAfterEvent>(OnDevourWindup);
        SubscribeLocalEvent<ChangelingDevourComponent, ChangelingDevourConsumeDoAfterEvent>(OnDevourConsume);
        SubscribeLocalEvent<ChangelingDevourComponent, ComponentShutdown>(OnShutdown);
    }

    private void OnMapInit(Entity<ChangelingDevourComponent> ent, ref MapInitEvent args)
    {
        _actionsSystem.AddAction(ent, ref ent.Comp.ChangelingDevourActionEntity, ent.Comp.ChangelingDevourAction);
    }

    private void OnShutdown(Entity<ChangelingDevourComponent> ent, ref ComponentShutdown args)
    {
        if (ent.Comp.ChangelingDevourActionEntity != null)
        {
            _actionsSystem.RemoveAction(ent.Owner, ent.Comp.ChangelingDevourActionEntity);
        }
    }

    // The action was used.
    // Start the first doafter for the windup.
    private void OnDevourAction(Entity<ChangelingDevourComponent> ent, ref ChangelingDevourActionEvent args)
    {
        if (args.Handled
            || _whitelistSystem.IsWhitelistFailOrNull(ent.Comp.Whitelist, args.Target))
            return;

        args.Handled = true;
        var target = args.Target;

        if (!CanDevour(ent.AsNullable(), target))
            return;

        if (_net.IsServer)
        {
            ent.Comp.CurrentDevourSound = _audio.Stop(ent.Comp.CurrentDevourSound);
            ent.Comp.CurrentDevourSound = _audio.PlayPvs(ent.Comp.DevourWindupNoise, ent)?.Entity;
        }

        _adminLogger.Add(LogType.Action, LogImpact.Medium, $"{ent:player} started changeling devour windup against {target:player}");

        _doAfterSystem.TryStartDoAfter(new DoAfterArgs(EntityManager, ent, ent.Comp.DevourWindupTime, new ChangelingDevourWindupDoAfterEvent(), ent, target: target, used: ent)
        {
            BreakOnMove = true,
            CancelDuplicate = true,
            DuplicateCondition = DuplicateConditions.None,
            ExamineText = ent.Comp.WindupExamine == null ? null : Loc.GetString(ent.Comp.WindupExamine, ("user", Identity.Entity(ent, EntityManager)), ("target", Identity.Entity(target, EntityManager)))
        });

        var selfMessage = Loc.GetString("changeling-devour-begin-windup-self", ("user", Identity.Entity(ent.Owner, EntityManager)));
        var othersMessage = Loc.GetString("changeling-devour-begin-windup-others", ("user", Identity.Entity(ent.Owner, EntityManager)));
        _popupSystem.PopupEntity(
            selfMessage,
            othersMessage,
            args.Performer,
            args.Performer,
            PopupType.MediumCaution);
    }

    // First doafter finished.
    // Start the second doafter for the actual consumption and deal a small amount of damage.
    private void OnDevourWindup(Entity<ChangelingDevourComponent> ent, ref ChangelingDevourWindupDoAfterEvent args)
    {
        args.Handled = true;
        ent.Comp.CurrentDevourSound = _audio.Stop(ent.Comp.CurrentDevourSound);

        if (args.Cancelled)
            return;

        if (args.Target is not { } target)
            return;

        _damageable.ChangeDamage(target, ent.Comp.WindupDamage, true, true, ent.Owner);

        var selfMessage = Loc.GetString("changeling-devour-begin-consume-self", ("user", Identity.Entity(ent.Owner, EntityManager)));
        var othersMessage = Loc.GetString("changeling-devour-begin-consume-others", ("user", Identity.Entity(ent.Owner, EntityManager)));
        _popupSystem.PopupEntity(
            selfMessage,
            othersMessage,
            ent.Owner,
            ent.Owner,
            PopupType.LargeCaution);

        if (_net.IsServer)
            ent.Comp.CurrentDevourSound = _audio.PlayPvs(ent.Comp.ConsumeNoise, ent)?.Entity;

        _adminLogger.Add(LogType.Action, LogImpact.Medium, $"{ToPrettyString(ent.Owner):player} began to devour {ToPrettyString(target):player}'s identity");

        _doAfterSystem.TryStartDoAfter(new DoAfterArgs(EntityManager,
            ent,
            ent.Comp.DevourConsumeTime,
            new ChangelingDevourConsumeDoAfterEvent(),
            ent,
            target: target,
            used: ent)
        {
            BreakOnMove = true,
            CancelDuplicate = true,
            DuplicateCondition = DuplicateConditions.None,
            ExamineText = ent.Comp.DevourExamine == null ? null : Loc.GetString(ent.Comp.DevourExamine, ("user", Identity.Entity(ent, EntityManager)), ("target", Identity.Entity(target, EntityManager)))
        });
    }

    // Second doafter finished.
    // Save the identity and deal more damage.
    private void OnDevourConsume(Entity<ChangelingDevourComponent> ent, ref ChangelingDevourConsumeDoAfterEvent args)
    {
        args.Handled = true;
        ent.Comp.CurrentDevourSound = _audio.Stop(ent.Comp.CurrentDevourSound);

        if (args.Cancelled)
            return;

        if (args.Target is not { } target)
            return;

        // Damage first before the CanDevour check to make sure they don't gib in-between and to kill them again in case they somehow revived.
        _damageable.ChangeDamage(target, ent.Comp.DevourDamage, true, true, ent.Owner);

        if (!CanDevour(ent.AsNullable(), target)) // Check again if the conditions are still met.
            return;

        var selfMessage = Loc.GetString("changeling-devour-consume-complete-self", ("user", Identity.Entity(ent.Owner, EntityManager)));
        var othersMessage = Loc.GetString("changeling-devour-consume-complete-others", ("user", Identity.Entity(ent.Owner, EntityManager)));
        _popupSystem.PopupEntity(
            selfMessage,
            othersMessage,
            ent.Owner,
            ent.Owner,
            PopupType.LargeCaution);

        _adminLogger.Add(LogType.Action, LogImpact.Medium, $"{ToPrettyString(ent.Owner):player} successfully devoured {ToPrettyString(target):player}'s identity");

        // A unique identity is separate from whether we have actually devoured this target before.
        var uniqueIdentity = IsUniqueDevour(ent.Owner, target);
        var willGrantDna = WillDevourGrantDna(ent.Owner, target);

        // Even if not unique, target is supposed to give us an identity if it is not currently in our identity list.
        var becomesIdentity = !_changelingIdentity.HasIdentity(ent.Owner, target);

        var ev = new ChangelingDevouredEvent(ent.Owner, target, becomesIdentity, uniqueIdentity, willGrantDna);
        RaiseLocalEvent(ent, ref ev, true); // We broadcast the event to allow relevant objectives to update.

        var devouredEv = new ChangelingGotDevouredEvent(ent.Owner, target, becomesIdentity, uniqueIdentity, willGrantDna);
        RaiseLocalEvent(target, ref devouredEv); // Don't broadcast this one, all neccessary data is in the previous event already. Just use that one if a broadcast is needed.

        EnsureComp<RecentlyDevouredComponent>(target);

        if (ent.Comp.DevourSpill != null)
        {
            // Spilled solution should have the same DNA as the changeling at the time of devouring
            var spill = ent.Comp.DevourSpill.Clone();
            if (TryComp<BloodstreamComponent>(ent, out var bloodstream))
                spill.SetReagentData(_bloodstream.GetEntityBloodData((ent, bloodstream)));

            _puddle.TrySpillAt(target, spill, out _, false);
        }

        // Grants the DNA reward associated with a successful unique devour.
        if (willGrantDna && TryComp<StoreComponent>(ent, out var store))
            _store.TryAddCurrency(ent.Comp.DevourDnaReward, ent.Owner, store);
    }

    /// <summary>
    /// Can the given changeling devour the given victim?
    /// </summary>
    public bool CanDevour(Entity<ChangelingDevourComponent?> changeling, EntityUid victim, bool checkDead = true, bool checkProtected = true, bool showPopup = true)
    {
        if (!Resolve(changeling, ref changeling.Comp))
            return false;

        if (changeling.Owner == victim)
            return false; // Can't devour yourself.

        if (!HasComp<HumanoidProfileComponent>(victim))
        {
            if (showPopup)
                _popupSystem.PopupEntity(Loc.GetString("changeling-devour-attempt-failed-cannot-devour"), changeling.Owner, changeling.Owner, PopupType.Medium);
            return false;
        }

        if (HasComp<RecentlyDevouredComponent>(victim))
        {
            if (showPopup)
                _popupSystem.PopupEntity(Loc.GetString("changeling-devour-attempt-failed-devoured-recently"), changeling.Owner, changeling.Owner, PopupType.Medium);
            return false;
        }

        if (checkDead && !_mobState.IsDead(victim))
        {
            if (showPopup)
                _popupSystem.PopupEntity(Loc.GetString("changeling-devour-attempt-failed-not-dead"), changeling.Owner, changeling.Owner, PopupType.Medium);
            return false;
        }

        if (HasComp<RottingComponent>(victim) || HasComp<ZombieComponent>(victim))
        {
            if (showPopup)
                _popupSystem.PopupEntity(Loc.GetString("changeling-devour-attempt-failed-rotting"), changeling.Owner, changeling.Owner, PopupType.Medium);
            return false;
        }

        if (checkProtected && IsTargetProtected(victim, changeling))
        {
            if (showPopup)
                _popupSystem.PopupEntity(Loc.GetString("changeling-devour-attempt-failed-protected"), changeling.Owner, changeling.Owner, PopupType.Medium);
            return false;
        }

        if (!_changelingIdentity.HasIdentity(changeling.Owner, victim) && !_changelingIdentity.HasFreeDisguiseSlot(changeling.Owner))
        {
            if (showPopup)
                _popupSystem.PopupEntity(Loc.GetString("changeling-devour-attempt-failed-no-space"), changeling.Owner, changeling.Owner, PopupType.Medium);
            return false;
        }

        return true;
    }

    /// <summary>
    /// Checks if the target's outerclothing is beyond a DamageCoefficientThreshold to protect them from being devoured.
    /// </summary>
    /// <param name="target">The Targeted entity</param>
    /// <param name="ent">Changelings Devour Component</param>
    /// <returns>Is the target Protected from the attack</returns>
    public bool IsTargetProtected(EntityUid target, Entity<ChangelingDevourComponent?> ent)
    {
        if (!Resolve(ent, ref ent.Comp, false))
            return false;

        var ev = new CoefficientQueryEvent(SlotFlags.OUTERCLOTHING);

        RaiseLocalEvent(target, ev);

        foreach (var compProtectiveDamageType in ent.Comp.ProtectiveDamageTypes)
        {
            if (!ev.DamageModifiers.Coefficients.TryGetValue(compProtectiveDamageType, out var coefficient))
                continue;
            if (coefficient < 1f - ent.Comp.DevourPreventionPercentageThreshold)
                return true;
        }

        return false;
    }

    /// <summary>
    /// Checks whether devouring this target has never been devoured by the changeling before.
    /// </summary>
    /// <param name="ent">The changeling.</param>
    /// <param name="devoured">The target entity.</param>
    /// <returns>True if the target was never devoured before, otherwise False.</returns>
    public bool IsUniqueDevour(Entity<ChangelingIdentityComponent?> ent, EntityUid devoured)
    {
        if (!Resolve(ent, ref ent.Comp, false))
            return false;

        return !_changelingIdentity.TryGetDataFromOriginal(ent, devoured, out _);
    }

    /// <summary>
    /// Checks whether devouring this entity will grant DNA to the changeling.
    /// </summary>
    /// <param name="ent">The changeling.</param>
    /// <param name="devoured">The target entity.</param>
    /// <returns>True if this target entity has granted the changeling DNA before, False otherwise.</returns>
    public bool WillDevourGrantDna(Entity<ChangelingIdentityComponent?> ent, EntityUid devoured)
    {
        if (!Resolve(ent, ref ent.Comp, false))
            return false;

        // This target was never devoured, so obviously it can grant us DNA.
        if (!_changelingIdentity.TryGetDataFromOriginal(ent, devoured, out var data))
            return true;

        // If the entity was Devoured, it means it already granted DNA, so we return False.
        return !data.GrantedDna;
    }
}