Delta-v/Content.Server/NodeContainer/NodeGroups/PipeNet.cs

using System.Linq;
using Content.Server.Atmos.EntitySystems;
using Content.Server.NodeContainer.Nodes;
using Content.Shared.Atmos;
using Content.Shared.NodeContainer;
using Content.Shared.NodeContainer.NodeGroups;

namespace Content.Server.NodeContainer.NodeGroups;

[NodeGroup(NodeGroupID.Pipe)]
public sealed class PipeNet : BaseNodeGroup, IPipeNet
{
    [ViewVariables] public GasMixture Air { get; set; } = new() {Temperature = Atmospherics.T20C};

    [ViewVariables] private AtmosphereSystem? _atmosphereSystem;

    public EntityUid? Grid { get; private set; }

    public override void Initialize(Node sourceNode, IEntityManager entMan)
    {
        base.Initialize(sourceNode, entMan);

        Grid = entMan.GetComponent<TransformComponent>(sourceNode.Owner).GridUid;

        if (Grid == null)
        {
            // This is probably due to a canister or something like that being spawned in space.
            return;
        }

        _atmosphereSystem = entMan.EntitySysManager.GetEntitySystem<AtmosphereSystem>();
        _atmosphereSystem.AddPipeNet(Grid.Value, this);
    }

    public void Update()
    {
        _atmosphereSystem?.React(Air, this);
    }

    public override void LoadNodes(List<Node> groupNodes)
    {
        base.LoadNodes(groupNodes);

        foreach (var node in groupNodes)
        {
            var pipeNode = (PipeNode) node;
            Air.Volume += pipeNode.Volume;
        }
    }

    public override void RemoveNode(Node node)
    {
        base.RemoveNode(node);

        // if the node is simply being removed into a separate group, we do nothing, as gas redistribution will be
        // handled by AfterRemake(). But if it is being deleted, we actually want to remove the gas stored in this node.
        if (!node.Deleting || node is not PipeNode pipe)
            return;

        Air.Multiply(1f - pipe.Volume / Air.Volume);
        Air.Volume -= pipe.Volume;
    }

    public override void AfterRemake(IEnumerable<IGrouping<INodeGroup?, Node>> newGroups)
    {
        RemoveFromGridAtmos();

        var newAir = new List<GasMixture>(newGroups.Count());
        foreach (var newGroup in newGroups)
        {
            if (newGroup.Key is IPipeNet newPipeNet)
                newAir.Add(newPipeNet.Air);
        }

        _atmosphereSystem?.DivideInto(Air, newAir);
    }

    private void RemoveFromGridAtmos()
    {
        if (Grid == null)
            return;

        _atmosphereSystem?.RemovePipeNet(Grid.Value, this);
    }

    public override string GetDebugData()
    {
        return @$"Pressure: { Air.Pressure:G3}
Temperature: {Air.Temperature:G3}
Volume: {Air.Volume:G3}";
    }
}