servicepoint-tanks/TanksServer/GameLogic/MapEntityManager.cs

namespace TanksServer.GameLogic;

internal sealed class MapEntityManager(
    ILogger<MapEntityManager> logger,
    MapService map
)
{
    private readonly HashSet<Bullet> _bullets = [];
    private readonly HashSet<Tank> _tanks = [];
    private readonly HashSet<PowerUp> _powerUps = [];

    public IEnumerable<Bullet> Bullets => _bullets;
    public IEnumerable<Tank> Tanks => _tanks;
    public IEnumerable<PowerUp> PowerUps => _powerUps;

    public IEnumerable<IMapEntity> AllEntities => Bullets
        .Cast<IMapEntity>()
        .Concat(Tanks)
        .Concat(PowerUps);

    public void SpawnBullet(Player tankOwner, FloatPosition position, double rotation, bool isExplosive)
        => _bullets.Add(new Bullet(tankOwner, position, rotation, isExplosive));

    public void RemoveBulletsWhere(Predicate<Bullet> predicate) => _bullets.RemoveWhere(predicate);

    public void SpawnTank(Player player)
    {
        _tanks.Add(new Tank(player, ChooseSpawnPosition())
        {
            Rotation = Random.Shared.NextDouble()
        });
        logger.LogInformation("Tank added for player {}", player.Id);
    }

    public void SpawnPowerUp() => _powerUps.Add(new PowerUp(ChooseSpawnPosition()));

    public void RemoveWhere(Predicate<PowerUp> predicate) => _powerUps.RemoveWhere(predicate);

    public void Remove(Tank tank)
    {
        logger.LogInformation("Tank removed for player {}", tank.Owner.Id);
        _tanks.Remove(tank);
    }

    public FloatPosition ChooseSpawnPosition()
    {
        Dictionary<TilePosition, double> candidates = [];

        for (ushort x = 1; x < MapService.TilesPerRow - 1; x++)
        for (ushort y = 1; y < MapService.TilesPerColumn - 1; y++)
        {
            var tile = new TilePosition(x, y);
            if (map.Current.IsWall(tile))
                continue;

            var tilePixelCenter = tile.ToPixelPosition().GetPixelRelative(4, 4).ToFloatPosition();

            var minDistance = AllEntities
                .Select(entity => entity.Position.Distance(tilePixelCenter))
                .Aggregate(double.MaxValue, Math.Min);

            candidates.Add(tile, minDistance);
        }

        var min = candidates.MaxBy(pair => pair.Value).Key;
        return min.ToPixelPosition().GetPixelRelative(4, 4).ToFloatPosition();
    }
}