tbd-station-14/Content.Shared/Weapons/Ranged/Systems/SharedGunSystem.Battery.cs

using Content.Shared.Damage;
using Content.Shared.Damage.Events;
using Content.Shared.Examine;
using Content.Shared.Projectiles;
using Content.Shared.Weapons.Hitscan.Components;
using Content.Shared.Weapons.Ranged.Components;
using Content.Shared.Weapons.Ranged.Events;
using Robust.Shared.GameStates;
using Robust.Shared.Map;
using Robust.Shared.Prototypes;
using Robust.Shared.Serialization;

namespace Content.Shared.Weapons.Ranged.Systems;

public abstract partial class SharedGunSystem
{
    protected virtual void InitializeBattery()
    {
        // Trying to dump comp references hence the below
        // Hitscan
        SubscribeLocalEvent<HitscanBatteryAmmoProviderComponent, ComponentGetState>(OnBatteryGetState);
        SubscribeLocalEvent<HitscanBatteryAmmoProviderComponent, ComponentHandleState>(OnBatteryHandleState);
        SubscribeLocalEvent<HitscanBatteryAmmoProviderComponent, TakeAmmoEvent>(OnBatteryTakeAmmo);
        SubscribeLocalEvent<HitscanBatteryAmmoProviderComponent, GetAmmoCountEvent>(OnBatteryAmmoCount);
        SubscribeLocalEvent<HitscanBatteryAmmoProviderComponent, ExaminedEvent>(OnBatteryExamine);
        SubscribeLocalEvent<HitscanBatteryAmmoProviderComponent, DamageExamineEvent>(OnBatteryDamageExamine);

        // Projectile
        SubscribeLocalEvent<ProjectileBatteryAmmoProviderComponent, ComponentGetState>(OnBatteryGetState);
        SubscribeLocalEvent<ProjectileBatteryAmmoProviderComponent, ComponentHandleState>(OnBatteryHandleState);
        SubscribeLocalEvent<ProjectileBatteryAmmoProviderComponent, TakeAmmoEvent>(OnBatteryTakeAmmo);
        SubscribeLocalEvent<ProjectileBatteryAmmoProviderComponent, GetAmmoCountEvent>(OnBatteryAmmoCount);
        SubscribeLocalEvent<ProjectileBatteryAmmoProviderComponent, ExaminedEvent>(OnBatteryExamine);
        SubscribeLocalEvent<ProjectileBatteryAmmoProviderComponent, DamageExamineEvent>(OnBatteryDamageExamine);
    }

    private void OnBatteryHandleState(EntityUid uid, BatteryAmmoProviderComponent component, ref ComponentHandleState args)
    {
        if (args.Current is not BatteryAmmoProviderComponentState state)
            return;

        component.Shots = state.Shots;
        component.Capacity = state.MaxShots;
        component.FireCost = state.FireCost;
        UpdateAmmoCount(uid, prediction: false);
    }

    private void OnBatteryGetState(EntityUid uid, BatteryAmmoProviderComponent component, ref ComponentGetState args)
    {
        args.State = new BatteryAmmoProviderComponentState()
        {
            Shots = component.Shots,
            MaxShots = component.Capacity,
            FireCost = component.FireCost,
        };
    }

    private void OnBatteryExamine(EntityUid uid, BatteryAmmoProviderComponent component, ExaminedEvent args)
    {
        args.PushMarkup(Loc.GetString("gun-battery-examine", ("color", AmmoExamineColor), ("count", component.Shots)));
    }

    private void OnBatteryDamageExamine<T>(Entity<T> entity, ref DamageExamineEvent args) where T : BatteryAmmoProviderComponent
    {
        var damageSpec = GetDamage(entity.Comp);

        if (damageSpec == null)
            return;

        var damageType = entity.Comp switch
        {
            HitscanBatteryAmmoProviderComponent => Loc.GetString("damage-hitscan"),
            ProjectileBatteryAmmoProviderComponent => Loc.GetString("damage-projectile"),
            _ => throw new ArgumentOutOfRangeException(),
        };

        _damageExamine.AddDamageExamine(args.Message, Damageable.ApplyUniversalAllModifiers(damageSpec), damageType);
    }

    private DamageSpecifier? GetDamage(BatteryAmmoProviderComponent component)
    {
        if (component is ProjectileBatteryAmmoProviderComponent battery)
        {
            if (ProtoManager.Index<EntityPrototype>(battery.Prototype).Components
                .TryGetValue(Factory.GetComponentName<ProjectileComponent>(), out var projectile))
            {
                var p = (ProjectileComponent) projectile.Component;

                if (!p.Damage.Empty)
                {
                    return p.Damage * Damageable.UniversalProjectileDamageModifier;
                }
            }

            return null;
        }

        if (component is HitscanBatteryAmmoProviderComponent hitscan)
        {
            var dmg = ProtoManager.Index(hitscan.HitscanEntityProto);
            if (!dmg.TryGetComponent<HitscanBasicDamageComponent>(out var basicDamageComp, Factory))
                return null;

            return basicDamageComp.Damage * Damageable.UniversalHitscanDamageModifier;
        }

        return null;
    }

    private void OnBatteryTakeAmmo(EntityUid uid, BatteryAmmoProviderComponent component, TakeAmmoEvent args)
    {
        var shots = Math.Min(args.Shots, component.Shots);

        // Don't dirty if it's an empty fire.
        if (shots == 0)
            return;

        for (var i = 0; i < shots; i++)
        {
            args.Ammo.Add(GetShootable(component, args.Coordinates));
            component.Shots--;
        }

        TakeCharge((uid, component));
        UpdateBatteryAppearance(uid, component);
        Dirty(uid, component);
    }

    private void OnBatteryAmmoCount(EntityUid uid, BatteryAmmoProviderComponent component, ref GetAmmoCountEvent args)
    {
        args.Count = component.Shots;
        args.Capacity = component.Capacity;
    }

    /// <summary>
    /// Update the battery (server-only) whenever fired.
    /// </summary>
    protected virtual void TakeCharge(Entity<BatteryAmmoProviderComponent> entity)
    {
        UpdateAmmoCount(entity, prediction: false);
    }

    protected void UpdateBatteryAppearance(EntityUid uid, BatteryAmmoProviderComponent component)
    {
        if (!TryComp<AppearanceComponent>(uid, out var appearance))
            return;

        Appearance.SetData(uid, AmmoVisuals.HasAmmo, component.Shots != 0, appearance);
        Appearance.SetData(uid, AmmoVisuals.AmmoCount, component.Shots, appearance);
        Appearance.SetData(uid, AmmoVisuals.AmmoMax, component.Capacity, appearance);
    }

    private (EntityUid? Entity, IShootable) GetShootable(BatteryAmmoProviderComponent component, EntityCoordinates coordinates)
    {
        switch (component)
        {
            case ProjectileBatteryAmmoProviderComponent proj:
                var ent = Spawn(proj.Prototype, coordinates);
                return (ent, EnsureShootable(ent));
            case HitscanBatteryAmmoProviderComponent hitscan:
                var hitscanEnt = Spawn(hitscan.HitscanEntityProto);
                return (hitscanEnt, EnsureShootable(hitscanEnt));
            default:
                throw new ArgumentOutOfRangeException();
        }
    }

    [Serializable, NetSerializable]
    private sealed class BatteryAmmoProviderComponentState : ComponentState
    {
        public int Shots;
        public int MaxShots;
        public float FireCost;
    }
}