tbd-station-14/Content.Server/GameTicking/Rules/GameRuleSystem.Utility.cs

using System.Diagnostics.CodeAnalysis;
using Content.Server.GameTicking.Components;
using Content.Server.GameTicking.Rules.Components;
using Content.Server.Station.Components;
using Robust.Shared.Collections;
using Robust.Shared.Map;
using Robust.Shared.Map.Components;
using Robust.Shared.Random;

namespace Content.Server.GameTicking.Rules;

public abstract partial class GameRuleSystem<T> where T: IComponent
{
    protected EntityQueryEnumerator<ActiveGameRuleComponent, T, GameRuleComponent> QueryActiveRules()
    {
        return EntityQueryEnumerator<ActiveGameRuleComponent, T, GameRuleComponent>();
    }

    /// <summary>
    ///     Utility function for finding a random event-eligible station entity
    /// </summary>
    protected bool TryGetRandomStation([NotNullWhen(true)] out EntityUid? station, Func<EntityUid, bool>? filter = null)
    {
        var stations = new ValueList<EntityUid>(Count<StationEventEligibleComponent>());

        filter ??= _ => true;
        var query = AllEntityQuery<StationEventEligibleComponent>();

        while (query.MoveNext(out var uid, out _))
        {
            if (!filter(uid))
                continue;

            stations.Add(uid);
        }

        if (stations.Count == 0)
        {
            station = null;
            return false;
        }

        // TODO: Engine PR.
        station = stations[RobustRandom.Next(stations.Count)];
        return true;
    }

    protected bool TryFindRandomTile(out Vector2i tile,
        [NotNullWhen(true)] out EntityUid? targetStation,
        out EntityUid targetGrid,
        out EntityCoordinates targetCoords)
    {
        tile = default;
        targetStation = EntityUid.Invalid;
        targetGrid = EntityUid.Invalid;
        targetCoords = EntityCoordinates.Invalid;
        if (TryGetRandomStation(out targetStation))
        {
            return TryFindRandomTileOnStation((targetStation.Value, Comp<StationDataComponent>(targetStation.Value)),
                out tile,
                out targetGrid,
                out targetCoords);
        }

        return false;
    }

    protected bool TryFindRandomTileOnStation(Entity<StationDataComponent> station,
        out Vector2i tile,
        out EntityUid targetGrid,
        out EntityCoordinates targetCoords)
    {
        tile = default;
        targetCoords = EntityCoordinates.Invalid;
        targetGrid = EntityUid.Invalid;

        var possibleTargets = station.Comp.Grids;
        if (possibleTargets.Count == 0)
        {
            targetGrid = EntityUid.Invalid;
            return false;
        }

        targetGrid = RobustRandom.Pick(possibleTargets);

        if (!TryComp<MapGridComponent>(targetGrid, out var gridComp))
            return false;

        var found = false;
        var aabb = gridComp.LocalAABB;

        for (var i = 0; i < 10; i++)
        {
            var randomX = RobustRandom.Next((int) aabb.Left, (int) aabb.Right);
            var randomY = RobustRandom.Next((int) aabb.Bottom, (int) aabb.Top);

            tile = new Vector2i(randomX, randomY);
            if (_atmosphere.IsTileSpace(targetGrid, Transform(targetGrid).MapUid, tile)
                || _atmosphere.IsTileAirBlocked(targetGrid, tile, mapGridComp: gridComp))
            {
                continue;
            }

            found = true;
            targetCoords = _map.GridTileToLocal(targetGrid, gridComp, tile);
            break;
        }

        return found;
    }

}