tbd-station-14/Content.Shared/Magic/SharedMagicSystem.cs

using System.Numerics;
using Content.Shared.Actions;
using Content.Shared.Body.Components;
using Content.Shared.Body.Systems;
using Content.Shared.Coordinates.Helpers;
using Content.Shared.Doors.Components;
using Content.Shared.Doors.Systems;
using Content.Shared.Hands.Components;
using Content.Shared.Hands.EntitySystems;
using Content.Shared.Interaction;
using Content.Shared.Inventory;
using Content.Shared.Lock;
using Content.Shared.Magic.Components;
using Content.Shared.Magic.Events;
using Content.Shared.Maps;
using Content.Shared.Physics;
using Content.Shared.Popups;
using Content.Shared.Speech.Muting;
using Content.Shared.Storage;
using Content.Shared.Tag;
using Content.Shared.Weapons.Ranged.Components;
using Content.Shared.Weapons.Ranged.Systems;
using Robust.Shared.Map;
using Robust.Shared.Map.Components;
using Robust.Shared.Network;
using Robust.Shared.Physics.Systems;
using Robust.Shared.Random;
using Robust.Shared.Serialization.Manager;
using Robust.Shared.Spawners;

namespace Content.Shared.Magic;

/// <summary>
/// Handles learning and using spells (actions)
/// </summary>
public abstract class SharedMagicSystem : EntitySystem
{
    [Dependency] private readonly ISerializationManager _seriMan = default!;
    [Dependency] private readonly IComponentFactory _compFact = default!;
    [Dependency] private readonly IMapManager _mapManager = default!;
    [Dependency] private readonly SharedMapSystem _mapSystem = default!;
    [Dependency] private readonly IRobustRandom _random = default!;
    [Dependency] private readonly SharedGunSystem _gunSystem = default!;
    [Dependency] private readonly SharedPhysicsSystem _physics = default!;
    [Dependency] private readonly SharedTransformSystem _transform = default!;
    [Dependency] private readonly INetManager _net = default!;
    [Dependency] private readonly SharedBodySystem _body = default!;
    [Dependency] private readonly EntityLookupSystem _lookup = default!;
    [Dependency] private readonly SharedDoorSystem _door = default!;
    [Dependency] private readonly InventorySystem _inventory = default!;
    [Dependency] private readonly SharedPopupSystem _popup = default!;
    [Dependency] private readonly SharedInteractionSystem _interaction = default!;
    [Dependency] private readonly LockSystem _lock = default!;
    [Dependency] private readonly SharedHandsSystem _hands = default!;
    [Dependency] private readonly TagSystem _tag = default!;

    public override void Initialize()
    {
        base.Initialize();
        SubscribeLocalEvent<MagicComponent, BeforeCastSpellEvent>(OnBeforeCastSpell);

        SubscribeLocalEvent<InstantSpawnSpellEvent>(OnInstantSpawn);
        SubscribeLocalEvent<TeleportSpellEvent>(OnTeleportSpell);
        SubscribeLocalEvent<WorldSpawnSpellEvent>(OnWorldSpawn);
        SubscribeLocalEvent<ProjectileSpellEvent>(OnProjectileSpell);
        SubscribeLocalEvent<ChangeComponentsSpellEvent>(OnChangeComponentsSpell);
        SubscribeLocalEvent<SmiteSpellEvent>(OnSmiteSpell);
        SubscribeLocalEvent<KnockSpellEvent>(OnKnockSpell);
        SubscribeLocalEvent<ChargeSpellEvent>(OnChargeSpell);

        // Spell wishlist
        //  A wishlish of spells that I'd like to implement or planning on implementing in a future PR

        // TODO: InstantDoAfterSpell and WorldDoafterSpell
        //  Both would be an action that take in an event, that passes an event to trigger once the doafter is done
        //  This would be three events:
        //    1 - Event that triggers from the action that starts the doafter
        //    2 - The doafter event itself, which passes the event with it
        //    3 - The event to trigger once the do-after finishes

        // TODO: Inanimate objects to life ECS
        //  AI sentience

        // TODO: Flesh2Stone
        //   Entity Target spell
        //   Synergy with Inanimate object to life (detects player and allows player to move around)

        // TODO: Lightning Spell
        // Should just fire lightning, try to prevent arc back to caster

        // TODO: Magic Missile (homing projectile ecs)
        //   Instant action, target any player (except self) on screen

        // TODO: Random projectile ECS for magic-carp, wand of magic

        // TODO: Recall Spell
        //  mark any item in hand to recall
        //    ItemRecallComponent
        //    Event adds the component if it doesn't exist and the performer isn't stored in the comp
        //    2nd firing of the event checks to see if the recall comp has this uid, and if it does it calls it
        //  if no free hands, summon at feet
        //  if item deleted, clear stored item

        // TODO: Jaunt (should be its own ECS)
        // Instant action
        //   When clicked, disappear/reappear (goes to paused map)
        //   option to restrict to tiles
        //   option for requiring entry/exit (blood jaunt)
        //   speed option

        // TODO: Summon Events
        //  List of wizard events to add into the event pool that frequently activate
        //  floor is lava
        //  change places
        //  ECS that when triggered, will periodically trigger a random GameRule
        //  Would need a controller/controller entity?

        // TODO: Summon Guns
        //  Summon a random gun at peoples feet
        //    Get every alive player (not in cryo, not a simplemob)
        //  TODO: After Antag Rework - Rare chance of giving gun collector status to people

        // TODO: Summon Magic
        //  Summon a random magic wand at peoples feet
        //    Get every alive player (not in cryo, not a simplemob)
        //  TODO: After Antag Rework - Rare chance of giving magic collector status to people

        // TODO: Bottle of Blood
        //  Summons Slaughter Demon
        //  TODO: Slaughter Demon
        //    Also see Jaunt

        // TODO: Field Spells
        //  Should be able to specify a grid of tiles (3x3 for example) that it effects
        //  Timed despawn - so it doesn't last forever
        //  Ignore caster - for spells that shouldn't effect the caster (ie if timestop should effect the caster)

        // TODO: Touch toggle spell
        //  1 - When toggled on, show in hand
        //  2 - Block hand when toggled on
        //      - Require free hand
        //  3 - use spell event when toggled & click
    }

    private void OnBeforeCastSpell(Entity<MagicComponent> ent, ref BeforeCastSpellEvent args)
    {
        var comp = ent.Comp;
        var hasReqs = true;

        if (comp.RequiresClothes)
        {
            var enumerator = _inventory.GetSlotEnumerator(args.Performer, SlotFlags.OUTERCLOTHING | SlotFlags.HEAD);
            while (enumerator.MoveNext(out var containerSlot))
            {
                if (containerSlot.ContainedEntity is { } item)
                    hasReqs = HasComp<WizardClothesComponent>(item);
                else
                    hasReqs = false;

                if (!hasReqs)
                    break;
            }
        }

        if (comp.RequiresSpeech && HasComp<MutedComponent>(args.Performer))
            hasReqs = false;

        if (hasReqs)
            return;

        args.Cancelled = true;
        _popup.PopupClient(Loc.GetString("spell-requirements-failed"), args.Performer, args.Performer);

        // TODO: Pre-cast do after, either here or in SharedActionsSystem
    }

    private bool PassesSpellPrerequisites(EntityUid spell, EntityUid performer)
    {
        var ev = new BeforeCastSpellEvent(performer);
        RaiseLocalEvent(spell, ref ev);
        return !ev.Cancelled;
    }

    #region Spells
    #region Instant Spawn Spells
    /// <summary>
    /// Handles the instant action (i.e. on the caster) attempting to spawn an entity.
    /// </summary>
    private void OnInstantSpawn(InstantSpawnSpellEvent args)
    {
        if (args.Handled || !PassesSpellPrerequisites(args.Action, args.Performer))
            return;

        var transform = Transform(args.Performer);

        foreach (var position in GetInstantSpawnPositions(transform, args.PosData))
        {
            SpawnSpellHelper(args.Prototype, position, args.Performer, preventCollide: args.PreventCollideWithCaster);
        }

        Speak(args);
        args.Handled = true;
    }

        /// <summary>
    ///     Gets spawn positions listed on <see cref="InstantSpawnSpellEvent"/>
    /// </summary>
    /// <exception cref="ArgumentOutOfRangeException"></exception>
    private List<EntityCoordinates> GetInstantSpawnPositions(TransformComponent casterXform, MagicInstantSpawnData data)
    {
        switch (data)
        {
            case TargetCasterPos:
                return new List<EntityCoordinates>(1) {casterXform.Coordinates};
            case TargetInFrontSingle:
            {
                var directionPos = casterXform.Coordinates.Offset(casterXform.LocalRotation.ToWorldVec().Normalized());

                if (!TryComp<MapGridComponent>(casterXform.GridUid, out var mapGrid))
                    return new List<EntityCoordinates>();
                if (!directionPos.TryGetTileRef(out var tileReference, EntityManager, _mapManager))
                    return new List<EntityCoordinates>();

                var tileIndex = tileReference.Value.GridIndices;
                return new List<EntityCoordinates>(1) { _mapSystem.GridTileToLocal(casterXform.GridUid.Value, mapGrid, tileIndex) };
            }
            case TargetInFront:
            {
                var directionPos = casterXform.Coordinates.Offset(casterXform.LocalRotation.ToWorldVec().Normalized());

                if (!TryComp<MapGridComponent>(casterXform.GridUid, out var mapGrid))
                    return new List<EntityCoordinates>();

                if (!directionPos.TryGetTileRef(out var tileReference, EntityManager, _mapManager))
                    return new List<EntityCoordinates>();

                var tileIndex = tileReference.Value.GridIndices;
                var coords = _mapSystem.GridTileToLocal(casterXform.GridUid.Value, mapGrid, tileIndex);
                EntityCoordinates coordsPlus;
                EntityCoordinates coordsMinus;

                var dir = casterXform.LocalRotation.GetCardinalDir();
                switch (dir)
                {
                    case Direction.North:
                    case Direction.South:
                    {
                        coordsPlus = _mapSystem.GridTileToLocal(casterXform.GridUid.Value, mapGrid, tileIndex + (1, 0));
                        coordsMinus = _mapSystem.GridTileToLocal(casterXform.GridUid.Value, mapGrid, tileIndex + (-1, 0));
                        return new List<EntityCoordinates>(3)
                        {
                            coords,
                            coordsPlus,
                            coordsMinus,
                        };
                    }
                    case Direction.East:
                    case Direction.West:
                    {
                        coordsPlus = _mapSystem.GridTileToLocal(casterXform.GridUid.Value, mapGrid, tileIndex + (0, 1));
                        coordsMinus = _mapSystem.GridTileToLocal(casterXform.GridUid.Value, mapGrid, tileIndex + (0, -1));
                        return new List<EntityCoordinates>(3)
                        {
                            coords,
                            coordsPlus,
                            coordsMinus,
                        };
                    }
                }

                return new List<EntityCoordinates>();
            }
            default:
                throw new ArgumentOutOfRangeException();
        }
    }
    // End Instant Spawn Spells
    #endregion
    #region World Spawn Spells
    /// <summary>
    /// Spawns entities from a list within range of click.
    /// </summary>
    /// <remarks>
    /// It will offset entities after the first entity based on the OffsetVector2.
    /// </remarks>
    /// <param name="args"> The Spawn Spell Event args.</param>
    private void OnWorldSpawn(WorldSpawnSpellEvent args)
    {
        if (args.Handled || !PassesSpellPrerequisites(args.Action, args.Performer))
            return;

        var targetMapCoords = args.Target;

        WorldSpawnSpellHelper(args.Prototypes, targetMapCoords, args.Performer, args.Lifetime, args.Offset);
        Speak(args);
        args.Handled = true;
    }

    /// <summary>
    /// Loops through a supplied list of entity prototypes and spawns them
    /// </summary>
    /// <remarks>
    /// If an offset of 0, 0 is supplied then the entities will all spawn on the same tile.
    /// Any other offset will spawn entities starting from the source Map Coordinates and will increment the supplied
    /// offset
    /// </remarks>
    /// <param name="entityEntries"> The list of Entities to spawn in</param>
    /// <param name="entityCoords"> Map Coordinates where the entities will spawn</param>
    /// <param name="lifetime"> Check to see if the entities should self delete</param>
    /// <param name="offsetVector2"> A Vector2 offset that the entities will spawn in</param>
    private void WorldSpawnSpellHelper(List<EntitySpawnEntry> entityEntries, EntityCoordinates entityCoords, EntityUid performer, float? lifetime, Vector2 offsetVector2)
    {
        var getProtos = EntitySpawnCollection.GetSpawns(entityEntries, _random);

        var offsetCoords = entityCoords;
        foreach (var proto in getProtos)
        {
            SpawnSpellHelper(proto, offsetCoords, performer, lifetime);
            offsetCoords = offsetCoords.Offset(offsetVector2);
        }
    }
    // End World Spawn Spells
    #endregion
    #region Projectile Spells
    private void OnProjectileSpell(ProjectileSpellEvent ev)
    {
        if (ev.Handled || !PassesSpellPrerequisites(ev.Action, ev.Performer) || !_net.IsServer)
            return;

        ev.Handled = true;
        Speak(ev);

        var xform = Transform(ev.Performer);
        var fromCoords = xform.Coordinates;
        var toCoords = ev.Target;
        var userVelocity = _physics.GetMapLinearVelocity(ev.Performer);

        // If applicable, this ensures the projectile is parented to grid on spawn, instead of the map.
        var fromMap = fromCoords.ToMap(EntityManager, _transform);
        var spawnCoords = _mapManager.TryFindGridAt(fromMap, out var gridUid, out _)
            ? fromCoords.WithEntityId(gridUid, EntityManager)
            : new(_mapManager.GetMapEntityId(fromMap.MapId), fromMap.Position);

        var ent = Spawn(ev.Prototype, spawnCoords);
        var direction = toCoords.ToMapPos(EntityManager, _transform) -
                        spawnCoords.ToMapPos(EntityManager, _transform);
        _gunSystem.ShootProjectile(ent, direction, userVelocity, ev.Performer, ev.Performer);
    }
    // End Projectile Spells
    #endregion
    #region Change Component Spells
    // staves.yml ActionRGB light
    private void OnChangeComponentsSpell(ChangeComponentsSpellEvent ev)
    {
        if (ev.Handled || !PassesSpellPrerequisites(ev.Action, ev.Performer))
            return;

        ev.Handled = true;
        Speak(ev);

        foreach (var toRemove in ev.ToRemove)
        {
            if (_compFact.TryGetRegistration(toRemove, out var registration))
                RemComp(ev.Target, registration.Type);
        }

        foreach (var (name, data) in ev.ToAdd)
        {
            if (HasComp(ev.Target, data.Component.GetType()))
                continue;

            var component = (Component) _compFact.GetComponent(name);
            component.Owner = ev.Target;
            var temp = (object) component;
            _seriMan.CopyTo(data.Component, ref temp);
            EntityManager.AddComponent(ev.Target, (Component) temp!);
        }
    }
    // End Change Component Spells
    #endregion
    #region Teleport Spells
    // TODO: Rename to teleport clicked spell?
    /// <summary>
    /// Teleports the user to the clicked location
    /// </summary>
    /// <param name="args"></param>
    private void OnTeleportSpell(TeleportSpellEvent args)
    {
        if (args.Handled || !PassesSpellPrerequisites(args.Action, args.Performer))
            return;

        var transform = Transform(args.Performer);

        if (transform.MapID != args.Target.GetMapId(EntityManager) || !_interaction.InRangeUnobstructed(args.Performer, args.Target, range: 1000F, collisionMask: CollisionGroup.Opaque, popup: true))
            return;

        _transform.SetCoordinates(args.Performer, args.Target);
        _transform.AttachToGridOrMap(args.Performer, transform);
        Speak(args);
        args.Handled = true;
    }
    // End Teleport Spells
    #endregion
    #region Spell Helpers
    private void SpawnSpellHelper(string? proto, EntityCoordinates position, EntityUid performer, float? lifetime = null, bool preventCollide = false)
    {
        if (!_net.IsServer)
            return;

        var ent = Spawn(proto, position.SnapToGrid(EntityManager, _mapManager));

        if (lifetime != null)
        {
            var comp = EnsureComp<TimedDespawnComponent>(ent);
            comp.Lifetime = lifetime.Value;
        }

        if (preventCollide)
        {
            var comp = EnsureComp<PreventCollideComponent>(ent);
            comp.Uid = performer;
        }
    }
    // End Spell Helpers
    #endregion
    #region Smite Spells
    private void OnSmiteSpell(SmiteSpellEvent ev)
    {
        if (ev.Handled || !PassesSpellPrerequisites(ev.Action, ev.Performer))
            return;

        ev.Handled = true;
        Speak(ev);

        var direction = _transform.GetMapCoordinates(ev.Target, Transform(ev.Target)).Position - _transform.GetMapCoordinates(ev.Performer, Transform(ev.Performer)).Position;
        var impulseVector = direction * 10000;

        _physics.ApplyLinearImpulse(ev.Target, impulseVector);

        if (!TryComp<BodyComponent>(ev.Target, out var body))
            return;

        _body.GibBody(ev.Target, true, body);
    }
    // End Smite Spells
    #endregion
    #region Knock Spells
    /// <summary>
    /// Opens all doors and locks within range
    /// </summary>
    /// <param name="args"></param>
    private void OnKnockSpell(KnockSpellEvent args)
    {
        if (args.Handled || !PassesSpellPrerequisites(args.Action, args.Performer))
            return;

        args.Handled = true;
        Speak(args);

        var transform = Transform(args.Performer);

        // Look for doors and lockers, and don't open/unlock them if they're already opened/unlocked.
        foreach (var target in _lookup.GetEntitiesInRange(_transform.GetMapCoordinates(args.Performer, transform), args.Range, flags: LookupFlags.Dynamic | LookupFlags.Static))
        {
            if (!_interaction.InRangeUnobstructed(args.Performer, target, range: 0, collisionMask: CollisionGroup.Opaque))
                continue;

            if (TryComp<DoorBoltComponent>(target, out var doorBoltComp) && doorBoltComp.BoltsDown)
                _door.SetBoltsDown((target, doorBoltComp), false, predicted: true);

            if (TryComp<DoorComponent>(target, out var doorComp) && doorComp.State is not DoorState.Open)
                _door.StartOpening(target);

            if (TryComp<LockComponent>(target, out var lockComp) && lockComp.Locked)
                _lock.Unlock(target, args.Performer, lockComp);
        }
    }
    // End Knock Spells
    #endregion
    #region Charge Spells
    // TODO: Future support to charge other items
    private void OnChargeSpell(ChargeSpellEvent ev)
    {
        if (ev.Handled || !PassesSpellPrerequisites(ev.Action, ev.Performer) || !TryComp<HandsComponent>(ev.Performer, out var handsComp))
            return;

        EntityUid? wand = null;
        foreach (var item in _hands.EnumerateHeld(ev.Performer, handsComp))
        {
            if (!_tag.HasTag(item, ev.WandTag))
                continue;

            wand = item;
        }

        ev.Handled = true;
        Speak(ev);

        if (wand == null || !TryComp<BasicEntityAmmoProviderComponent>(wand, out var basicAmmoComp) || basicAmmoComp.Count == null)
            return;

        _gunSystem.UpdateBasicEntityAmmoCount(wand.Value, basicAmmoComp.Count.Value + ev.Charge, basicAmmoComp);
    }
    // End Charge Spells
    #endregion
    // End Spells
    #endregion

    // When any spell is cast it will raise this as an event, so then it can be played in server or something. At least until chat gets moved to shared
    // TODO: Temp until chat is in shared
    private void Speak(BaseActionEvent args)
    {
        if (args is not ISpeakSpell speak || string.IsNullOrWhiteSpace(speak.Speech))
            return;

        var ev = new SpeakSpellEvent(args.Performer, speak.Speech);
        RaiseLocalEvent(ref ev);
    }
}