space-game/apps/backend/Simulation/SimulationEngine.cs

using SpaceGame.Simulation.Api.Data;
using SpaceGame.Simulation.Api.Contracts;

namespace SpaceGame.Simulation.Api.Simulation;

public sealed class SimulationEngine
{
  private const float ShipFuelToEnergyRatio = 12f;
  private const float StationFuelToEnergyRatio = 18f;
  private const float CapacitorEnergyPerModule = 120f;
  private const float StationEnergyPerPowerCore = 480f;
  private const float ShipFuelPerReactor = 100f;
  private const float StationFuelPerTank = 500f;
  private const float WaterConsumptionPerWorkerPerSecond = 0.004f;
  private const float PopulationGrowthPerSecond = 0.012f;
  private const float PopulationAttritionPerSecond = 0.018f;

  public WorldDelta Tick(SimulationWorld world, float deltaSeconds, long sequence)
  {
    var events = new List<SimulationEventRecord>();
    var nowUtc = DateTimeOffset.UtcNow;

    UpdateOrbitalState(world, nowUtc);

    UpdateClaims(world, events);
    UpdateConstructionSites(world, events);
    UpdateStationPower(world, deltaSeconds, events);
    UpdateStations(world, deltaSeconds, events);

    foreach (var ship in world.Ships)
    {
      var previousPosition = ship.Position;
      var previousState = ship.State;
      var previousBehavior = ship.DefaultBehavior.Kind;
      var previousTask = ship.ControllerTask.Kind;

      UpdateShipPower(ship, world, deltaSeconds, events);
      RefreshControlLayers(ship, world);
      PlanControllerTask(ship, world);
      var controllerEvent = UpdateControllerTask(ship, world, deltaSeconds);
      AdvanceControlState(ship, world, controllerEvent);
      ship.Velocity = ship.Position.Subtract(previousPosition).Divide(deltaSeconds);
      TrackHistory(ship);

      EmitShipStateEvents(ship, previousState, previousBehavior, previousTask, controllerEvent, events);
    }

    SyncSpatialState(world);
    world.GeneratedAtUtc = nowUtc;

    return new WorldDelta(
      sequence,
      world.TickIntervalMs,
      world.GeneratedAtUtc,
      false,
      events,
      BuildSpatialNodeDeltas(world),
      BuildLocalBubbleDeltas(world),
      BuildNodeDeltas(world),
      BuildStationDeltas(world),
      BuildClaimDeltas(world),
      BuildConstructionSiteDeltas(world),
      BuildMarketOrderDeltas(world),
      BuildPolicyDeltas(world),
      BuildShipDeltas(world),
      BuildFactionDeltas(world));
  }

  public WorldSnapshot BuildSnapshot(SimulationWorld world, long sequence)
  {
    PrimeDeltaBaseline(world);

    return new WorldSnapshot(
      world.Label,
      world.Seed,
      sequence,
      world.TickIntervalMs,
      world.GeneratedAtUtc,
      world.Systems.Select((system) => new SystemSnapshot(
        system.Definition.Id,
        system.Definition.Label,
        ToDto(system.Position),
        system.Definition.StarKind,
        system.Definition.StarCount,
        system.Definition.StarColor,
        system.Definition.StarSize,
        system.Definition.Planets.Select((planet) => new PlanetSnapshot(
          planet.Label,
          planet.PlanetType,
          planet.Shape,
          planet.MoonCount,
          planet.OrbitRadius,
          planet.OrbitSpeed,
          planet.OrbitEccentricity,
          planet.OrbitInclination,
          planet.OrbitLongitudeOfAscendingNode,
          planet.OrbitArgumentOfPeriapsis,
          planet.OrbitPhaseAtEpoch,
          planet.Size,
          planet.Color,
          planet.HasRing)).ToList())).ToList(),
      world.SpatialNodes.Select(ToSpatialNodeDelta).Select((node) => new SpatialNodeSnapshot(
        node.Id,
        node.SystemId,
        node.Kind,
        node.LocalPosition,
        node.BubbleId,
        node.ParentNodeId,
        node.OccupyingStructureId,
        node.OrbitReferenceId)).ToList(),
      world.LocalBubbles.Select(ToLocalBubbleDelta).Select((bubble) => new LocalBubbleSnapshot(
        bubble.Id,
        bubble.NodeId,
        bubble.SystemId,
        bubble.Radius,
        bubble.OccupantShipIds,
        bubble.OccupantStationIds,
        bubble.OccupantClaimIds,
        bubble.OccupantConstructionSiteIds)).ToList(),
      world.Nodes.Select(ToNodeDelta).Select((node) => new ResourceNodeSnapshot(
        node.Id,
        node.SystemId,
        node.LocalPosition,
        node.SourceKind,
        node.OreRemaining,
        node.MaxOre,
        node.ItemId)).ToList(),
      world.Stations.Select(ToStationDelta).Select((station) => new StationSnapshot(
        station.Id,
        station.Label,
        station.Category,
        station.SystemId,
        station.LocalPosition,
        station.NodeId,
        station.BubbleId,
        station.AnchorNodeId,
        station.Color,
        station.DockedShips,
        station.DockingPads,
        station.EnergyStored,
        station.Inventory,
        station.FactionId,
        station.CommanderId,
        station.PolicySetId,
        station.Population,
        station.PopulationCapacity,
        station.WorkforceRequired,
        station.WorkforceEffectiveRatio,
        station.InstalledModules,
        station.MarketOrderIds)).ToList(),
      world.Claims.Select(ToClaimDelta).Select((claim) => new ClaimSnapshot(
        claim.Id,
        claim.FactionId,
        claim.SystemId,
        claim.NodeId,
        claim.BubbleId,
        claim.State,
        claim.Health,
        claim.PlacedAtUtc,
        claim.ActivatesAtUtc)).ToList(),
      world.ConstructionSites.Select(ToConstructionSiteDelta).Select((site) => new ConstructionSiteSnapshot(
        site.Id,
        site.FactionId,
        site.SystemId,
        site.NodeId,
        site.BubbleId,
        site.TargetKind,
        site.TargetDefinitionId,
        site.BlueprintId,
        site.ClaimId,
        site.StationId,
        site.State,
        site.Progress,
        site.Inventory,
        site.RequiredItems,
        site.DeliveredItems,
        site.AssignedConstructorShipIds,
        site.MarketOrderIds)).ToList(),
      world.MarketOrders.Select(ToMarketOrderDelta).Select((order) => new MarketOrderSnapshot(
        order.Id,
        order.FactionId,
        order.StationId,
        order.ConstructionSiteId,
        order.Kind,
        order.ItemId,
        order.Amount,
        order.RemainingAmount,
        order.Valuation,
        order.ReserveThreshold,
        order.PolicySetId,
        order.State)).ToList(),
      world.Policies.Select(ToPolicySetDelta).Select((policy) => new PolicySetSnapshot(
        policy.Id,
        policy.OwnerKind,
        policy.OwnerId,
        policy.TradeAccessPolicy,
        policy.DockingAccessPolicy,
        policy.ConstructionAccessPolicy,
        policy.OperationalRangePolicy)).ToList(),
      world.Ships.Select(ToShipDelta).Select((ship) => new ShipSnapshot(
        ship.Id,
        ship.Label,
        ship.Role,
        ship.ShipClass,
        ship.SystemId,
        ship.LocalPosition,
        ship.LocalVelocity,
        ship.TargetLocalPosition,
        ship.State,
        ship.OrderKind,
        ship.DefaultBehaviorKind,
        ship.ControllerTaskKind,
        ship.NodeId,
        ship.BubbleId,
        ship.DockedStationId,
        ship.CommanderId,
        ship.PolicySetId,
        ship.CargoCapacity,
        ship.WorkerPopulation,
        ship.EnergyStored,
        ship.Inventory,
        ship.FactionId,
        ship.Health,
        ship.History,
        ship.SpatialState)).ToList(),
      world.Factions.Select(ToFactionDelta).Select((faction) => new FactionSnapshot(
        faction.Id,
        faction.Label,
        faction.Color,
        faction.Credits,
        faction.PopulationTotal,
        faction.OreMined,
        faction.GoodsProduced,
        faction.ShipsBuilt,
        faction.ShipsLost,
        faction.DefaultPolicySetId)).ToList());
  }

  public void PrimeDeltaBaseline(SimulationWorld world)
  {
    foreach (var node in world.Nodes)
    {
      node.LastDeltaSignature = BuildNodeSignature(node);
    }

    foreach (var node in world.SpatialNodes)
    {
      node.LastDeltaSignature = BuildSpatialNodeSignature(node);
    }

    foreach (var bubble in world.LocalBubbles)
    {
      bubble.LastDeltaSignature = BuildLocalBubbleSignature(bubble);
    }

    foreach (var station in world.Stations)
    {
      station.LastDeltaSignature = BuildStationSignature(station);
    }

    foreach (var claim in world.Claims)
    {
      claim.LastDeltaSignature = BuildClaimSignature(claim);
    }

    foreach (var site in world.ConstructionSites)
    {
      site.LastDeltaSignature = BuildConstructionSiteSignature(site);
    }

    foreach (var order in world.MarketOrders)
    {
      order.LastDeltaSignature = BuildMarketOrderSignature(order);
    }

    foreach (var policy in world.Policies)
    {
      policy.LastDeltaSignature = BuildPolicySignature(policy);
    }

    foreach (var ship in world.Ships)
    {
      ship.LastDeltaSignature = BuildShipSignature(ship);
    }

    foreach (var faction in world.Factions)
    {
      faction.LastDeltaSignature = BuildFactionSignature(faction);
    }
  }

  private static IReadOnlyList<ResourceNodeDelta> BuildNodeDeltas(SimulationWorld world)
  {
    var deltas = new List<ResourceNodeDelta>();
    foreach (var node in world.Nodes)
    {
      var signature = BuildNodeSignature(node);
      if (signature == node.LastDeltaSignature)
      {
        continue;
      }

      node.LastDeltaSignature = signature;
      deltas.Add(ToNodeDelta(node));
    }

    return deltas;
  }

  private static IReadOnlyList<SpatialNodeDelta> BuildSpatialNodeDeltas(SimulationWorld world)
  {
    var deltas = new List<SpatialNodeDelta>();
    foreach (var node in world.SpatialNodes)
    {
      var signature = BuildSpatialNodeSignature(node);
      if (signature == node.LastDeltaSignature)
      {
        continue;
      }

      node.LastDeltaSignature = signature;
      deltas.Add(ToSpatialNodeDelta(node));
    }

    return deltas;
  }

  private static IReadOnlyList<LocalBubbleDelta> BuildLocalBubbleDeltas(SimulationWorld world)
  {
    var deltas = new List<LocalBubbleDelta>();
    foreach (var bubble in world.LocalBubbles)
    {
      var signature = BuildLocalBubbleSignature(bubble);
      if (signature == bubble.LastDeltaSignature)
      {
        continue;
      }

      bubble.LastDeltaSignature = signature;
      deltas.Add(ToLocalBubbleDelta(bubble));
    }

    return deltas;
  }

  private static IReadOnlyList<StationDelta> BuildStationDeltas(SimulationWorld world)
  {
    var deltas = new List<StationDelta>();
    foreach (var station in world.Stations)
    {
      var signature = BuildStationSignature(station);
      if (signature == station.LastDeltaSignature)
      {
        continue;
      }

      station.LastDeltaSignature = signature;
      deltas.Add(ToStationDelta(station));
    }

    return deltas;
  }

  private static IReadOnlyList<ClaimDelta> BuildClaimDeltas(SimulationWorld world)
  {
    var deltas = new List<ClaimDelta>();
    foreach (var claim in world.Claims)
    {
      var signature = BuildClaimSignature(claim);
      if (signature == claim.LastDeltaSignature)
      {
        continue;
      }

      claim.LastDeltaSignature = signature;
      deltas.Add(ToClaimDelta(claim));
    }

    return deltas;
  }

  private static IReadOnlyList<ConstructionSiteDelta> BuildConstructionSiteDeltas(SimulationWorld world)
  {
    var deltas = new List<ConstructionSiteDelta>();
    foreach (var site in world.ConstructionSites)
    {
      var signature = BuildConstructionSiteSignature(site);
      if (signature == site.LastDeltaSignature)
      {
        continue;
      }

      site.LastDeltaSignature = signature;
      deltas.Add(ToConstructionSiteDelta(site));
    }

    return deltas;
  }

  private static IReadOnlyList<MarketOrderDelta> BuildMarketOrderDeltas(SimulationWorld world)
  {
    var deltas = new List<MarketOrderDelta>();
    foreach (var order in world.MarketOrders)
    {
      var signature = BuildMarketOrderSignature(order);
      if (signature == order.LastDeltaSignature)
      {
        continue;
      }

      order.LastDeltaSignature = signature;
      deltas.Add(ToMarketOrderDelta(order));
    }

    return deltas;
  }

  private static IReadOnlyList<PolicySetDelta> BuildPolicyDeltas(SimulationWorld world)
  {
    var deltas = new List<PolicySetDelta>();
    foreach (var policy in world.Policies)
    {
      var signature = BuildPolicySignature(policy);
      if (signature == policy.LastDeltaSignature)
      {
        continue;
      }

      policy.LastDeltaSignature = signature;
      deltas.Add(ToPolicySetDelta(policy));
    }

    return deltas;
  }

  private static IReadOnlyList<ShipDelta> BuildShipDeltas(SimulationWorld world)
  {
    var deltas = new List<ShipDelta>();
    foreach (var ship in world.Ships)
    {
      var signature = BuildShipSignature(ship);
      if (signature == ship.LastDeltaSignature)
      {
        continue;
      }

      ship.LastDeltaSignature = signature;
      deltas.Add(ToShipDelta(ship));
    }

    return deltas;
  }

  private static IReadOnlyList<FactionDelta> BuildFactionDeltas(SimulationWorld world)
  {
    var deltas = new List<FactionDelta>();
    foreach (var faction in world.Factions)
    {
      var signature = BuildFactionSignature(faction);
      if (signature == faction.LastDeltaSignature)
      {
        continue;
      }

      faction.LastDeltaSignature = signature;
      deltas.Add(ToFactionDelta(faction));
    }

    return deltas;
  }

  private static string BuildNodeSignature(ResourceNodeRuntime node) =>
    $"{node.SystemId}|{node.OreRemaining:0.###}";

  private static string BuildSpatialNodeSignature(NodeRuntime node) =>
    $"{node.SystemId}|{node.Kind}|{node.Position.X:0.###}|{node.Position.Y:0.###}|{node.Position.Z:0.###}|{node.BubbleId}|{node.ParentNodeId}|{node.OccupyingStructureId}|{node.OrbitReferenceId}";

  private static string BuildLocalBubbleSignature(LocalBubbleRuntime bubble) =>
    $"{bubble.SystemId}|{bubble.NodeId}|{bubble.Radius:0.###}|{string.Join(",", bubble.OccupantShipIds.OrderBy((id) => id, StringComparer.Ordinal))}|{string.Join(",", bubble.OccupantStationIds.OrderBy((id) => id, StringComparer.Ordinal))}|{string.Join(",", bubble.OccupantClaimIds.OrderBy((id) => id, StringComparer.Ordinal))}|{string.Join(",", bubble.OccupantConstructionSiteIds.OrderBy((id) => id, StringComparer.Ordinal))}";

  private static Vector3 ComputePlanetPosition(PlanetDefinition planet, float timeSeconds)
  {
    var eccentricity = Math.Clamp(planet.OrbitEccentricity, 0f, 0.85f);
    var meanAnomaly = DegreesToRadians(planet.OrbitPhaseAtEpoch) + (timeSeconds * planet.OrbitSpeed);
    var eccentricAnomaly = meanAnomaly
      + (eccentricity * MathF.Sin(meanAnomaly))
      + (0.5f * eccentricity * eccentricity * MathF.Sin(2f * meanAnomaly));
    var semiMajorAxis = planet.OrbitRadius;
    var semiMinorAxis = semiMajorAxis * MathF.Sqrt(MathF.Max(1f - (eccentricity * eccentricity), 0.05f));
    var local = new Vector3(
      semiMajorAxis * (MathF.Cos(eccentricAnomaly) - eccentricity),
      0f,
      semiMinorAxis * MathF.Sin(eccentricAnomaly));

    local = RotateAroundY(local, DegreesToRadians(planet.OrbitArgumentOfPeriapsis));
    local = RotateAroundX(local, DegreesToRadians(planet.OrbitInclination));
    local = RotateAroundY(local, DegreesToRadians(planet.OrbitLongitudeOfAscendingNode));
    return local;
  }

  private static Vector3 ComputeMoonOffset(PlanetDefinition planet, int moonIndex, float timeSeconds)
  {
    var orbitRadius = ComputeMoonOrbitRadius(planet, moonIndex);
    var speed = ComputeMoonOrbitSpeed(planet, moonIndex);
    var phase = HashUnit($"{planet.Label}:{moonIndex}:phase") * MathF.PI * 2f;
    var inclination = DegreesToRadians((HashUnit($"{planet.Label}:{moonIndex}:inclination") - 0.5f) * 28f);
    var ascendingNode = DegreesToRadians(HashUnit($"{planet.Label}:{moonIndex}:node") * 360f);
    var angle = phase + (timeSeconds * speed);

    var local = new Vector3(
      MathF.Cos(angle) * orbitRadius,
      0f,
      MathF.Sin(angle) * orbitRadius);
    local = RotateAroundX(local, inclination);
    local = RotateAroundY(local, ascendingNode);
    return local;
  }

  private static float ComputeMoonOrbitRadius(PlanetDefinition planet, int moonIndex)
  {
    var spacing = planet.Size * 1.4f;
    var variance = HashUnit($"{planet.Label}:{moonIndex}:radius") * planet.Size * 0.9f;
    return (planet.Size * 1.8f) + (moonIndex * spacing) + variance;
  }

  private static float ComputeMoonOrbitSpeed(PlanetDefinition planet, int moonIndex)
  {
    var radius = ComputeMoonOrbitRadius(planet, moonIndex);
    return 0.9f / MathF.Sqrt(MathF.Max(radius, 1f)) + (moonIndex * 0.003f);
  }

  private static IEnumerable<LagrangePointPlacement> EnumeratePlanetLagrangePoints(Vector3 planetPosition, float orbitRadius, int planetIndex)
  {
    var radial = NormalizeOrFallback(planetPosition, new Vector3(1f, 0f, 0f));
    var tangential = new Vector3(-radial.Z, 0f, radial.X);
    var offset = MathF.Max(orbitRadius * 0.18f, 72f + (planetIndex * 6f));
    var triangularAngle = MathF.PI / 3f;

    yield return new LagrangePointPlacement("L1", Add(planetPosition, Scale(radial, -offset)));
    yield return new LagrangePointPlacement("L2", Add(planetPosition, Scale(radial, offset)));
    yield return new LagrangePointPlacement("L3", Scale(radial, -orbitRadius));
    yield return new LagrangePointPlacement(
      "L4",
      Add(Scale(radial, orbitRadius * MathF.Cos(triangularAngle)), Scale(tangential, orbitRadius * MathF.Sin(triangularAngle))));
    yield return new LagrangePointPlacement(
      "L5",
      Add(Scale(radial, orbitRadius * MathF.Cos(triangularAngle)), Scale(tangential, -orbitRadius * MathF.Sin(triangularAngle))));
  }

  private static Vector3 NormalizeOrFallback(Vector3 value, Vector3 fallback)
  {
    var length = MathF.Sqrt(value.LengthSquared());
    if (length <= 0.0001f)
    {
      return fallback;
    }

    return value.Divide(length);
  }

  private static Vector3 RotateAroundX(Vector3 value, float angle)
  {
    var cos = MathF.Cos(angle);
    var sin = MathF.Sin(angle);
    return new Vector3(
      value.X,
      (value.Y * cos) - (value.Z * sin),
      (value.Y * sin) + (value.Z * cos));
  }

  private static Vector3 RotateAroundY(Vector3 value, float angle)
  {
    var cos = MathF.Cos(angle);
    var sin = MathF.Sin(angle);
    return new Vector3(
      (value.X * cos) + (value.Z * sin),
      value.Y,
      (-value.X * sin) + (value.Z * cos));
  }

  private static Vector3 Add(Vector3 left, Vector3 right) => new(left.X + right.X, left.Y + right.Y, left.Z + right.Z);

  private static Vector3 Scale(Vector3 value, float scalar) => new(value.X * scalar, value.Y * scalar, value.Z * scalar);

  private static float DegreesToRadians(float degrees) => degrees * (MathF.PI / 180f);

  private static float HashUnit(string input)
  {
    unchecked
    {
      var hash = 2166136261u;
      foreach (var character in input)
      {
        hash ^= character;
        hash *= 16777619u;
      }

      return (hash & 0x00FFFFFF) / (float)0x01000000;
    }
  }

  private static void UpdateOrbitalState(SimulationWorld world, DateTimeOffset nowUtc)
  {
    var worldTimeSeconds = (float)(nowUtc.ToUnixTimeMilliseconds() / 1000d) + (world.Seed * 97f);
    var spatialNodesById = world.SpatialNodes.ToDictionary((node) => node.Id, StringComparer.Ordinal);

    foreach (var system in world.Systems)
    {
      var starNodeId = $"node-{system.Definition.Id}-star";
      if (spatialNodesById.TryGetValue(starNodeId, out var starNode))
      {
        starNode.Position = Vector3.Zero;
      }

      for (var planetIndex = 0; planetIndex < system.Definition.Planets.Count; planetIndex += 1)
      {
        var planet = system.Definition.Planets[planetIndex];
        var planetNodeId = $"node-{system.Definition.Id}-planet-{planetIndex + 1}";
        if (!spatialNodesById.TryGetValue(planetNodeId, out var planetNode))
        {
          continue;
        }

        var planetPosition = ComputePlanetPosition(planet, worldTimeSeconds);
        planetNode.Position = planetPosition;

        foreach (var lagrange in EnumeratePlanetLagrangePoints(planetPosition, planet.OrbitRadius, planetIndex))
        {
          var lagrangeId = $"node-{system.Definition.Id}-planet-{planetIndex + 1}-{lagrange.Designation.ToLowerInvariant()}";
          if (spatialNodesById.TryGetValue(lagrangeId, out var lagrangeNode))
          {
            lagrangeNode.Position = lagrange.Position;
          }
        }

        var moonCount = planet.MoonCount;
        for (var moonIndex = 0; moonIndex < moonCount; moonIndex += 1)
        {
          var moonId = $"node-{system.Definition.Id}-planet-{planetIndex + 1}-moon-{moonIndex + 1}";
          if (!spatialNodesById.TryGetValue(moonId, out var moonNode))
          {
            continue;
          }

          moonNode.Position = Add(planetPosition, ComputeMoonOffset(planet, moonIndex, worldTimeSeconds));
        }
      }
    }

    foreach (var station in world.Stations)
    {
      if (station.AnchorNodeId is null || !spatialNodesById.TryGetValue(station.AnchorNodeId, out var anchorNode))
      {
        continue;
      }

      station.Position = anchorNode.Position;
      if (station.NodeId is not null && spatialNodesById.TryGetValue(station.NodeId, out var stationNode))
      {
        stationNode.Position = station.Position;
      }
    }

    foreach (var ship in world.Ships)
    {
      if (ship.DockedStationId is null)
      {
        continue;
      }

      var station = world.Stations.FirstOrDefault((candidate) => candidate.Id == ship.DockedStationId);
      if (station is null)
      {
        continue;
      }

      var dockedPosition = GetShipDockedPosition(ship, station);
      ship.Position = dockedPosition;
      ship.TargetPosition = dockedPosition;
    }
  }

  private static void SyncSpatialState(SimulationWorld world)
  {
    foreach (var bubble in world.LocalBubbles)
    {
      bubble.OccupantShipIds.Clear();
    }

    foreach (var ship in world.Ships)
    {
      ship.SpatialState.CurrentSystemId = ship.SystemId;
      ship.SpatialState.LocalPosition = ship.Position;
      ship.SpatialState.SystemPosition = ship.Position;
      if (ship.SpatialState.Transit is not null)
      {
        ship.SpatialState.CurrentNodeId = null;
        ship.SpatialState.CurrentBubbleId = null;
        continue;
      }

      ship.SpatialState.SpaceLayer = SpaceLayerKinds.LocalSpace;
      ship.SpatialState.MovementRegime = MovementRegimeKinds.LocalFlight;
      var nearestNode = world.SpatialNodes
        .Where((candidate) => candidate.SystemId == ship.SystemId)
        .OrderBy((candidate) => candidate.Position.DistanceTo(ship.Position))
        .FirstOrDefault();
      ship.SpatialState.CurrentNodeId = nearestNode?.Id;
      ship.SpatialState.CurrentBubbleId = nearestNode?.BubbleId;

      if (nearestNode is not null)
      {
        var nearestBubble = world.LocalBubbles.FirstOrDefault((candidate) => candidate.Id == nearestNode.BubbleId);
        nearestBubble?.OccupantShipIds.Add(ship.Id);
      }

      if (ship.DockedStationId is null)
      {
        continue;
      }

      var station = world.Stations.FirstOrDefault((candidate) => candidate.Id == ship.DockedStationId);
      if (station?.BubbleId is null)
      {
        continue;
      }

      ship.SpatialState.CurrentNodeId = station.NodeId;
      ship.SpatialState.CurrentBubbleId = station.BubbleId;
      var bubble = world.LocalBubbles.FirstOrDefault((candidate) => candidate.Id == station.BubbleId);
      bubble?.OccupantShipIds.Add(ship.Id);
    }
  }

  private static string BuildStationSignature(StationRuntime station) =>
    $"{station.SystemId}|{station.NodeId}|{station.BubbleId}|{station.AnchorNodeId}|{station.CommanderId}|{station.PolicySetId}|{BuildInventorySignature(station.Inventory)}|{station.EnergyStored:0.###}|{station.DockedShipIds.Count}|{station.DockingPadAssignments.Count}|{station.Population:0.###}|{station.PopulationCapacity:0.###}|{station.WorkforceRequired:0.###}|{station.WorkforceEffectiveRatio:0.###}|{string.Join(",", station.InstalledModules.OrderBy((moduleId) => moduleId, StringComparer.Ordinal))}|{string.Join(",", station.MarketOrderIds.OrderBy((orderId) => orderId, StringComparer.Ordinal))}|{station.ActiveConstruction?.ModuleId ?? "none"}|{station.ActiveConstruction?.ProgressSeconds.ToString("0.###") ?? "0"}";

  private static string BuildClaimSignature(ClaimRuntime claim) =>
    $"{claim.FactionId}|{claim.SystemId}|{claim.NodeId}|{claim.BubbleId}|{claim.State}|{claim.Health:0.###}|{claim.ActivatesAtUtc:O}";

  private static string BuildConstructionSiteSignature(ConstructionSiteRuntime site) =>
    $"{site.FactionId}|{site.SystemId}|{site.NodeId}|{site.BubbleId}|{site.TargetKind}|{site.TargetDefinitionId}|{site.BlueprintId}|{site.ClaimId}|{site.StationId}|{site.State}|{site.Progress:0.###}|{BuildInventorySignature(site.Inventory)}|{BuildInventorySignature(site.RequiredItems)}|{BuildInventorySignature(site.DeliveredItems)}|{string.Join(",", site.AssignedConstructorShipIds.OrderBy((id) => id, StringComparer.Ordinal))}|{string.Join(",", site.MarketOrderIds.OrderBy((id) => id, StringComparer.Ordinal))}";

  private static string BuildMarketOrderSignature(MarketOrderRuntime order) =>
    $"{order.FactionId}|{order.StationId}|{order.ConstructionSiteId}|{order.Kind}|{order.ItemId}|{order.Amount:0.###}|{order.RemainingAmount:0.###}|{order.Valuation:0.###}|{order.ReserveThreshold?.ToString("0.###") ?? "none"}|{order.PolicySetId}|{order.State}";

  private static string BuildPolicySignature(PolicySetRuntime policy) =>
    $"{policy.OwnerKind}|{policy.OwnerId}|{policy.TradeAccessPolicy}|{policy.DockingAccessPolicy}|{policy.ConstructionAccessPolicy}|{policy.OperationalRangePolicy}";

  private static string BuildShipSignature(ShipRuntime ship) =>
    string.Join("|",
      ship.SystemId,
      ship.Position.X.ToString("0.###"),
      ship.Position.Y.ToString("0.###"),
      ship.Position.Z.ToString("0.###"),
      ship.Velocity.X.ToString("0.###"),
      ship.Velocity.Y.ToString("0.###"),
      ship.Velocity.Z.ToString("0.###"),
      ship.TargetPosition.X.ToString("0.###"),
      ship.TargetPosition.Y.ToString("0.###"),
      ship.TargetPosition.Z.ToString("0.###"),
      ship.State,
      ship.Order?.Kind ?? "none",
      ship.DefaultBehavior.Kind,
      ship.ControllerTask.Kind,
      ship.SpatialState.CurrentNodeId ?? "none",
      ship.SpatialState.CurrentBubbleId ?? "none",
      ship.DockedStationId ?? "none",
      ship.CommanderId ?? "none",
      ship.PolicySetId ?? "none",
      ship.WorkerPopulation.ToString("0.###"),
      ship.SpatialState.SpaceLayer,
      ship.SpatialState.CurrentNodeId ?? "none",
      ship.SpatialState.CurrentBubbleId ?? "none",
      ship.SpatialState.MovementRegime,
      ship.SpatialState.DestinationNodeId ?? "none",
      ship.SpatialState.Transit?.Regime ?? "none",
      ship.SpatialState.Transit?.OriginNodeId ?? "none",
      ship.SpatialState.Transit?.DestinationNodeId ?? "none",
      ship.SpatialState.Transit?.Progress.ToString("0.###") ?? "0",
      GetShipCargoAmount(ship).ToString("0.###"),
      GetInventoryAmount(ship.Inventory, "fuel").ToString("0.###"),
      ship.EnergyStored.ToString("0.###"),
      ship.Health.ToString("0.###"));

  private static string BuildInventorySignature(IReadOnlyDictionary<string, float> inventory) =>
    string.Join(",",
      inventory
        .Where((entry) => entry.Value > 0.001f)
        .OrderBy((entry) => entry.Key, StringComparer.Ordinal)
        .Select((entry) => $"{entry.Key}:{entry.Value:0.###}"));

  private static string BuildFactionSignature(FactionRuntime faction) =>
    $"{faction.Credits:0.###}|{faction.PopulationTotal:0.###}|{faction.OreMined:0.###}|{faction.GoodsProduced:0.###}|{faction.ShipsBuilt}|{faction.ShipsLost}|{faction.DefaultPolicySetId}";

  private static ResourceNodeDelta ToNodeDelta(ResourceNodeRuntime node) => new(
    node.Id,
    node.SystemId,
    ToDto(node.Position),
    node.SourceKind,
    node.OreRemaining,
    node.MaxOre,
    node.ItemId);

  private static SpatialNodeDelta ToSpatialNodeDelta(NodeRuntime node) => new(
    node.Id,
    node.SystemId,
    node.Kind,
    ToDto(node.Position),
    node.BubbleId,
    node.ParentNodeId,
    node.OccupyingStructureId,
    node.OrbitReferenceId);

  private static LocalBubbleDelta ToLocalBubbleDelta(LocalBubbleRuntime bubble) => new(
    bubble.Id,
    bubble.NodeId,
    bubble.SystemId,
    bubble.Radius,
    bubble.OccupantShipIds.OrderBy((id) => id, StringComparer.Ordinal).ToList(),
    bubble.OccupantStationIds.OrderBy((id) => id, StringComparer.Ordinal).ToList(),
    bubble.OccupantClaimIds.OrderBy((id) => id, StringComparer.Ordinal).ToList(),
    bubble.OccupantConstructionSiteIds.OrderBy((id) => id, StringComparer.Ordinal).ToList());

  private static StationDelta ToStationDelta(StationRuntime station) => new(
    station.Id,
    station.Definition.Label,
    station.Definition.Category,
    station.SystemId,
    ToDto(station.Position),
    station.NodeId,
    station.BubbleId,
    station.AnchorNodeId,
    station.Definition.Color,
    station.DockedShipIds.Count,
    GetDockingPadCount(station),
    station.EnergyStored,
    ToInventoryEntries(station.Inventory),
    station.FactionId,
    station.CommanderId,
    station.PolicySetId,
    station.Population,
    station.PopulationCapacity,
    station.WorkforceRequired,
    station.WorkforceEffectiveRatio,
    station.InstalledModules.OrderBy((moduleId) => moduleId, StringComparer.Ordinal).ToList(),
    station.MarketOrderIds.OrderBy((orderId) => orderId, StringComparer.Ordinal).ToList());

  private static ClaimDelta ToClaimDelta(ClaimRuntime claim) => new(
    claim.Id,
    claim.FactionId,
    claim.SystemId,
    claim.NodeId,
    claim.BubbleId,
    claim.State,
    claim.Health,
    claim.PlacedAtUtc,
    claim.ActivatesAtUtc);

  private static ConstructionSiteDelta ToConstructionSiteDelta(ConstructionSiteRuntime site) => new(
    site.Id,
    site.FactionId,
    site.SystemId,
    site.NodeId,
    site.BubbleId,
    site.TargetKind,
    site.TargetDefinitionId,
    site.BlueprintId,
    site.ClaimId,
    site.StationId,
    site.State,
    site.Progress,
    ToInventoryEntries(site.Inventory),
    ToInventoryEntries(site.RequiredItems),
    ToInventoryEntries(site.DeliveredItems),
    site.AssignedConstructorShipIds.OrderBy((id) => id, StringComparer.Ordinal).ToList(),
    site.MarketOrderIds.OrderBy((id) => id, StringComparer.Ordinal).ToList());

  private static MarketOrderDelta ToMarketOrderDelta(MarketOrderRuntime order) => new(
    order.Id,
    order.FactionId,
    order.StationId,
    order.ConstructionSiteId,
    order.Kind,
    order.ItemId,
    order.Amount,
    order.RemainingAmount,
    order.Valuation,
    order.ReserveThreshold,
    order.PolicySetId,
    order.State);

  private static PolicySetDelta ToPolicySetDelta(PolicySetRuntime policy) => new(
    policy.Id,
    policy.OwnerKind,
    policy.OwnerId,
    policy.TradeAccessPolicy,
    policy.DockingAccessPolicy,
    policy.ConstructionAccessPolicy,
    policy.OperationalRangePolicy);

  private static ShipDelta ToShipDelta(ShipRuntime ship) => new(
    ship.Id,
    ship.Definition.Label,
    ship.Definition.Role,
    ship.Definition.ShipClass,
    ship.SystemId,
    ToDto(ship.Position),
    ToDto(ship.Velocity),
    ToDto(ship.TargetPosition),
    ship.State,
    ship.Order?.Kind,
    ship.DefaultBehavior.Kind,
    ship.ControllerTask.Kind,
    ship.SpatialState.CurrentNodeId,
    ship.SpatialState.CurrentBubbleId,
    ship.DockedStationId,
    ship.CommanderId,
    ship.PolicySetId,
    ship.Definition.CargoCapacity,
    ship.WorkerPopulation,
    ship.EnergyStored,
    ToInventoryEntries(ship.Inventory),
    ship.FactionId,
    ship.Health,
    ship.History.ToList(),
    ToShipSpatialStateSnapshot(ship.SpatialState));

  private static IReadOnlyList<InventoryEntry> ToInventoryEntries(IReadOnlyDictionary<string, float> inventory) =>
    inventory
      .Where((entry) => entry.Value > 0.001f)
      .OrderBy((entry) => entry.Key, StringComparer.Ordinal)
      .Select((entry) => new InventoryEntry(entry.Key, entry.Value))
      .ToList();

  private static FactionDelta ToFactionDelta(FactionRuntime faction) => new(
    faction.Id,
    faction.Label,
    faction.Color,
    faction.Credits,
    faction.PopulationTotal,
    faction.OreMined,
    faction.GoodsProduced,
    faction.ShipsBuilt,
    faction.ShipsLost,
    faction.DefaultPolicySetId);

  private static ShipSpatialStateSnapshot ToShipSpatialStateSnapshot(ShipSpatialStateRuntime state) => new(
    state.SpaceLayer,
    state.CurrentSystemId,
    state.CurrentNodeId,
    state.CurrentBubbleId,
    state.LocalPosition is null ? null : ToDto(state.LocalPosition.Value),
    state.SystemPosition is null ? null : ToDto(state.SystemPosition.Value),
    state.MovementRegime,
    state.DestinationNodeId,
    state.Transit is null ? null : new ShipTransitSnapshot(
      state.Transit.Regime,
      state.Transit.OriginNodeId,
      state.Transit.DestinationNodeId,
      state.Transit.StartedAtUtc,
      state.Transit.ArrivalDueAtUtc,
      state.Transit.Progress));

  private static void EmitShipStateEvents(
    ShipRuntime ship,
    string previousState,
    string previousBehavior,
    string previousTask,
    string controllerEvent,
    ICollection<SimulationEventRecord> events)
  {
    var occurredAtUtc = DateTimeOffset.UtcNow;

    if (previousState != ship.State)
    {
      events.Add(new SimulationEventRecord("ship", ship.Id, "state-changed", $"{ship.Definition.Label} {previousState} -> {ship.State}", occurredAtUtc));
    }

    if (previousBehavior != ship.DefaultBehavior.Kind)
    {
      events.Add(new SimulationEventRecord("ship", ship.Id, "behavior-changed", $"{ship.Definition.Label} behavior {previousBehavior} -> {ship.DefaultBehavior.Kind}", occurredAtUtc));
    }

    if (previousTask != ship.ControllerTask.Kind)
    {
      events.Add(new SimulationEventRecord("ship", ship.Id, "task-changed", $"{ship.Definition.Label} task {previousTask} -> {ship.ControllerTask.Kind}", occurredAtUtc));
    }

    if (controllerEvent != "none")
    {
      events.Add(new SimulationEventRecord("ship", ship.Id, controllerEvent, $"{ship.Definition.Label} {controllerEvent}", occurredAtUtc));
    }
  }

  private void UpdateStations(SimulationWorld world, float deltaSeconds, ICollection<SimulationEventRecord> events)
  {
    var factionPopulation = new Dictionary<string, float>(StringComparer.Ordinal);
    foreach (var station in world.Stations)
    {
      UpdateStationPopulation(station, deltaSeconds, events);
      ReviewStationMarketOrders(world, station);
      RunStationProduction(world, station, deltaSeconds, events);
      factionPopulation[station.FactionId] = GetInventoryAmount(factionPopulation, station.FactionId) + station.Population;
    }

    foreach (var faction in world.Factions)
    {
      faction.PopulationTotal = GetInventoryAmount(factionPopulation, faction.Id);
    }
  }

  private void UpdateStationPopulation(StationRuntime station, float deltaSeconds, ICollection<SimulationEventRecord> events)
  {
    station.WorkforceRequired = MathF.Max(12f, station.InstalledModules.Count * 14f);

    var requiredWater = station.Population * WaterConsumptionPerWorkerPerSecond * deltaSeconds;
    var consumedWater = RemoveInventory(station.Inventory, "water", requiredWater);
    var waterSatisfied = requiredWater <= 0.01f || consumedWater + 0.001f >= requiredWater;
    var hasPower = station.EnergyStored > 0.01f;
    var habitatModules = CountModules(station.InstalledModules, "habitat-ring");
    station.PopulationCapacity = 40f + (habitatModules * 220f);

    if (waterSatisfied && hasPower)
    {
      if (habitatModules > 0 && station.Population < station.PopulationCapacity)
      {
        station.Population = MathF.Min(station.PopulationCapacity, station.Population + (PopulationGrowthPerSecond * deltaSeconds));
      }
    }
    else if (station.Population > 0f)
    {
      var previous = station.Population;
      station.Population = MathF.Max(0f, station.Population - (PopulationAttritionPerSecond * deltaSeconds));
      if (MathF.Floor(previous) > MathF.Floor(station.Population))
      {
        events.Add(new SimulationEventRecord("station", station.Id, "population-loss", $"{station.Definition.Label} lost population due to support shortages.", DateTimeOffset.UtcNow));
      }
    }

    station.WorkforceEffectiveRatio = ComputeWorkforceRatio(station.Population, station.WorkforceRequired);
  }

  private void ReviewStationMarketOrders(SimulationWorld world, StationRuntime station)
  {
    if (station.CommanderId is null)
    {
      return;
    }

    var desiredOrders = new List<DesiredMarketOrder>();
    var fuelReserve = MathF.Max(80f, CountModules(station.InstalledModules, "power-core") * 140f);
    var waterReserve = MathF.Max(30f, station.Population * 3f);
    var refinedReserve = HasStationModules(station, "fabricator-array") ? 140f : 40f;
    var oreReserve = HasRefineryCapability(station) ? 180f : 0f;
    var gasReserve = CanProcessFuel(station) ? 120f : 0f;

    AddDemandOrder(desiredOrders, station, "fuel", fuelReserve, valuationBase: 1.2f);
    AddDemandOrder(desiredOrders, station, "water", waterReserve, valuationBase: 1.1f);
    AddDemandOrder(desiredOrders, station, "ore", oreReserve, valuationBase: 1.0f);
    AddDemandOrder(desiredOrders, station, "gas", gasReserve, valuationBase: 0.95f);
    AddDemandOrder(desiredOrders, station, "refined-metals", refinedReserve, valuationBase: 1.15f);

    AddSupplyOrder(desiredOrders, station, "fuel", fuelReserve * 1.5f, reserveFloor: fuelReserve, valuationBase: 0.8f);
    AddSupplyOrder(desiredOrders, station, "water", waterReserve * 1.5f, reserveFloor: waterReserve, valuationBase: 0.65f);
    AddSupplyOrder(desiredOrders, station, "ore", oreReserve * 1.4f, reserveFloor: oreReserve, valuationBase: 0.7f);
    AddSupplyOrder(desiredOrders, station, "gas", gasReserve * 1.4f, reserveFloor: gasReserve, valuationBase: 0.72f);
    AddSupplyOrder(desiredOrders, station, "refined-metals", refinedReserve * 1.4f, reserveFloor: refinedReserve, valuationBase: 0.95f);

    ReconcileStationMarketOrders(world, station, desiredOrders);
  }

  private void RunStationProduction(SimulationWorld world, StationRuntime station, float deltaSeconds, ICollection<SimulationEventRecord> events)
  {
    var recipe = SelectProductionRecipe(world, station);
    if (recipe is null || station.EnergyStored <= 0.01f)
    {
      station.ProcessTimer = 0f;
      return;
    }

    if (!TryConsumeStationEnergy(station, world.Balance.Energy.MoveDrain * deltaSeconds))
    {
      station.ProcessTimer = 0f;
      return;
    }

    station.ProcessTimer += deltaSeconds * station.WorkforceEffectiveRatio;
    if (station.ProcessTimer < recipe.Duration)
    {
      return;
    }

    station.ProcessTimer = 0f;
    foreach (var input in recipe.Inputs)
    {
      RemoveInventory(station.Inventory, input.ItemId, input.Amount);
    }

    var produced = 0f;
    foreach (var output in recipe.Outputs)
    {
      produced += TryAddStationInventory(world, station, output.ItemId, output.Amount);
    }

    if (produced <= 0.01f)
    {
      return;
    }

    events.Add(new SimulationEventRecord("station", station.Id, "production-complete", $"{station.Definition.Label} completed {recipe.Label}.", DateTimeOffset.UtcNow));
    var faction = world.Factions.FirstOrDefault((candidate) => candidate.Id == station.FactionId);
    if (faction is not null)
    {
      faction.GoodsProduced += produced;
    }
  }

  private static RecipeDefinition? SelectProductionRecipe(SimulationWorld world, StationRuntime station)
  {
    return world.Recipes.Values
      .Where((recipe) => RecipeAppliesToStation(station, recipe))
      .OrderByDescending((recipe) => recipe.Priority)
      .FirstOrDefault((recipe) => CanRunRecipe(world, station, recipe));
  }

  private static bool RecipeAppliesToStation(StationRuntime station, RecipeDefinition recipe)
  {
    var categoryMatch = string.Equals(station.Definition.Category, recipe.FacilityCategory, StringComparison.Ordinal)
      || (string.Equals(recipe.FacilityCategory, "station", StringComparison.Ordinal)
        && station.Definition.Category is "station" or "shipyard" or "defense" or "gate");
    return categoryMatch && recipe.RequiredModules.All((moduleId) => station.InstalledModules.Contains(moduleId, StringComparer.Ordinal));
  }

  private static bool CanRunRecipe(SimulationWorld world, StationRuntime station, RecipeDefinition recipe)
  {
    if (recipe.Inputs.Any((input) => GetInventoryAmount(station.Inventory, input.ItemId) + 0.001f < input.Amount))
    {
      return false;
    }

    return recipe.Outputs.All((output) => CanAcceptStationInventory(world, station, output.ItemId, output.Amount));
  }

  private static bool CanAcceptStationInventory(SimulationWorld world, StationRuntime station, string itemId, float amount)
  {
    if (amount <= 0f || !world.ItemDefinitions.TryGetValue(itemId, out var itemDefinition))
    {
      return false;
    }

    var requiredModule = GetStorageRequirement(itemDefinition.Storage);
    if (requiredModule is not null && !station.InstalledModules.Contains(requiredModule, StringComparer.Ordinal))
    {
      return false;
    }

    if (!station.Definition.Storage.TryGetValue(itemDefinition.Storage, out var capacity))
    {
      return false;
    }

    var used = station.Inventory
      .Where((entry) => world.ItemDefinitions.TryGetValue(entry.Key, out var definition) && definition.Storage == itemDefinition.Storage)
      .Sum((entry) => entry.Value);
    return used + amount <= capacity + 0.001f;
  }

  private static void AddDemandOrder(ICollection<DesiredMarketOrder> desiredOrders, StationRuntime station, string itemId, float targetAmount, float valuationBase)
  {
    var current = GetInventoryAmount(station.Inventory, itemId);
    if (current >= targetAmount - 0.01f)
    {
      return;
    }

    var deficit = targetAmount - current;
    var scarcity = targetAmount <= 0.01f ? 1f : MathF.Min(1f, deficit / targetAmount);
    desiredOrders.Add(new DesiredMarketOrder(MarketOrderKinds.Buy, itemId, deficit, valuationBase + scarcity, null));
  }

  private static void AddSupplyOrder(ICollection<DesiredMarketOrder> desiredOrders, StationRuntime station, string itemId, float triggerAmount, float reserveFloor, float valuationBase)
  {
    var current = GetInventoryAmount(station.Inventory, itemId);
    if (current <= triggerAmount + 0.01f)
    {
      return;
    }

    var surplus = current - reserveFloor;
    if (surplus <= 0.01f)
    {
      return;
    }

    desiredOrders.Add(new DesiredMarketOrder(MarketOrderKinds.Sell, itemId, surplus, valuationBase, reserveFloor));
  }

  private static void ReconcileStationMarketOrders(SimulationWorld world, StationRuntime station, IReadOnlyCollection<DesiredMarketOrder> desiredOrders)
  {
    var existingOrders = world.MarketOrders
      .Where((order) => order.StationId == station.Id && order.ConstructionSiteId is null)
      .ToList();

    foreach (var desired in desiredOrders)
    {
      var order = existingOrders.FirstOrDefault((candidate) =>
        candidate.Kind == desired.Kind &&
        candidate.ItemId == desired.ItemId &&
        candidate.ConstructionSiteId is null);

      if (order is null)
      {
        order = new MarketOrderRuntime
        {
          Id = $"market-order-{station.Id}-{desired.Kind}-{desired.ItemId}",
          FactionId = station.FactionId,
          StationId = station.Id,
          Kind = desired.Kind,
          ItemId = desired.ItemId,
          Amount = desired.Amount,
          RemainingAmount = desired.Amount,
          Valuation = desired.Valuation,
          ReserveThreshold = desired.ReserveThreshold,
          State = MarketOrderStateKinds.Open,
        };
        world.MarketOrders.Add(order);
        station.MarketOrderIds.Add(order.Id);
        existingOrders.Add(order);
        continue;
      }

      order.RemainingAmount = desired.Amount;
      order.Valuation = desired.Valuation;
      order.ReserveThreshold = desired.ReserveThreshold;
      order.State = desired.Amount <= 0.01f ? MarketOrderStateKinds.Cancelled : MarketOrderStateKinds.Open;
    }

    foreach (var order in existingOrders)
    {
      if (desiredOrders.Any((desired) => desired.Kind == order.Kind && desired.ItemId == order.ItemId))
      {
        continue;
      }

      order.RemainingAmount = 0f;
      order.State = MarketOrderStateKinds.Cancelled;
    }
  }

  private static bool HasRefineryCapability(StationRuntime station) =>
    HasStationModules(station, "refinery-stack", "power-core", "bulk-bay");

  private static bool CanProcessFuel(StationRuntime station) =>
    HasStationModules(station, "fuel-processor", "power-core", "gas-tank", "liquid-tank");

  private static bool HasShipModules(ShipDefinition definition, params string[] modules) =>
    modules.All((moduleId) => definition.Modules.Contains(moduleId, StringComparer.Ordinal));

  private static bool CanTransportWorkers(ShipRuntime ship) =>
    CountModules(ship.Definition.Modules, "habitat-ring") > 0;

  private static float GetWorkerTransportCapacity(ShipRuntime ship) =>
    CountModules(ship.Definition.Modules, "habitat-ring") * 120f;

  private static void UpdateStationPower(
    SimulationWorld world,
    float deltaSeconds,
    ICollection<SimulationEventRecord> events)
  {
    foreach (var station in world.Stations)
    {
      var previousEnergy = station.EnergyStored;
      GenerateStationEnergy(station, deltaSeconds);

      if (previousEnergy > 0.01f && station.EnergyStored <= 0.01f && GetInventoryAmount(station.Inventory, "fuel") <= 0.01f)
      {
        events.Add(new SimulationEventRecord("station", station.Id, "power-lost", $"{station.Definition.Label} ran out of fuel and power", DateTimeOffset.UtcNow));
      }
    }
  }

  private static void UpdateShipPower(
    ShipRuntime ship,
    SimulationWorld world,
    float deltaSeconds,
    ICollection<SimulationEventRecord> events)
  {
    var previousEnergy = ship.EnergyStored;
    GenerateShipEnergy(ship, world, deltaSeconds);

    if (previousEnergy > 0.01f && ship.EnergyStored <= 0.01f && GetInventoryAmount(ship.Inventory, "fuel") <= 0.01f)
    {
      events.Add(new SimulationEventRecord("ship", ship.Id, "power-lost", $"{ship.Definition.Label} ran out of fuel and power", DateTimeOffset.UtcNow));
    }
  }

  private static void GenerateStationEnergy(StationRuntime station, float deltaSeconds)
  {
    var powerCores = CountModules(station.InstalledModules, "power-core");
    var tanks = CountModules(station.InstalledModules, "liquid-tank");
    if (powerCores <= 0 || tanks <= 0)
    {
      station.EnergyStored = 0f;
      station.Inventory.Remove("fuel");
      return;
    }

    var energyCapacity = powerCores * StationEnergyPerPowerCore;
    var fuelStored = GetInventoryAmount(station.Inventory, "fuel");
    var desiredEnergy = MathF.Max(0f, energyCapacity - station.EnergyStored);
    if (desiredEnergy <= 0.01f || fuelStored <= 0.01f)
    {
      station.EnergyStored = MathF.Min(station.EnergyStored, energyCapacity);
      station.Inventory["fuel"] = MathF.Min(fuelStored, tanks * StationFuelPerTank);
      return;
    }

    var generated = MathF.Min(desiredEnergy, powerCores * 24f * deltaSeconds);
    var requiredFuel = generated / StationFuelToEnergyRatio;
    var consumedFuel = MathF.Min(requiredFuel, fuelStored);
    var actualGenerated = consumedFuel * StationFuelToEnergyRatio;

    RemoveInventory(station.Inventory, "fuel", consumedFuel);
    station.EnergyStored = MathF.Min(energyCapacity, station.EnergyStored + actualGenerated);
  }

  private static void GenerateShipEnergy(ShipRuntime ship, SimulationWorld world, float deltaSeconds)
  {
    var reactors = CountModules(ship.Definition.Modules, "reactor-core");
    var capacitors = CountModules(ship.Definition.Modules, "capacitor-bank");
    if (reactors <= 0 || capacitors <= 0)
    {
      ship.EnergyStored = 0f;
      ship.Inventory.Remove("fuel");
      return;
    }

    var energyCapacity = capacitors * CapacitorEnergyPerModule;
    var fuelCapacity = reactors * ShipFuelPerReactor;
    var fuelStored = GetInventoryAmount(ship.Inventory, "fuel");
    var desiredEnergy = MathF.Max(0f, energyCapacity - ship.EnergyStored);
    if (desiredEnergy <= 0.01f || fuelStored <= 0.01f)
    {
      ship.EnergyStored = MathF.Min(ship.EnergyStored, energyCapacity);
      ship.Inventory["fuel"] = MathF.Min(fuelStored, fuelCapacity);
      return;
    }

    var generated = MathF.Min(desiredEnergy, world.Balance.Energy.ShipRechargeRate * reactors * deltaSeconds);
    var requiredFuel = generated / ShipFuelToEnergyRatio;
    var consumedFuel = MathF.Min(requiredFuel, fuelStored);
    var actualGenerated = consumedFuel * ShipFuelToEnergyRatio;

    RemoveInventory(ship.Inventory, "fuel", consumedFuel);
    ship.EnergyStored = MathF.Min(energyCapacity, ship.EnergyStored + actualGenerated);
  }

  private static bool TryConsumeShipEnergy(ShipRuntime ship, float amount)
  {
    if (ship.EnergyStored + 0.0001f < amount)
    {
      return false;
    }

    ship.EnergyStored = MathF.Max(0f, ship.EnergyStored - amount);
    return true;
  }

  private static bool TryConsumeStationEnergy(StationRuntime station, float amount)
  {
    if (station.EnergyStored + 0.0001f < amount)
    {
      return false;
    }

    station.EnergyStored = MathF.Max(0f, station.EnergyStored - amount);
    return true;
  }

  private static int CountModules(IEnumerable<string> modules, string moduleId) =>
    modules.Count((candidate) => string.Equals(candidate, moduleId, StringComparison.Ordinal));

  private static float GetInventoryAmount(IReadOnlyDictionary<string, float> inventory, string itemId) =>
    inventory.TryGetValue(itemId, out var amount) ? amount : 0f;

  private static void AddInventory(IDictionary<string, float> inventory, string itemId, float amount)
  {
    if (amount <= 0f)
    {
      return;
    }

    inventory[itemId] = GetInventoryAmount((IReadOnlyDictionary<string, float>)inventory, itemId) + amount;
  }

  private static float RemoveInventory(IDictionary<string, float> inventory, string itemId, float amount)
  {
    var current = GetInventoryAmount((IReadOnlyDictionary<string, float>)inventory, itemId);
    var removed = MathF.Min(current, amount);
    var remaining = current - removed;
    if (remaining <= 0.001f)
    {
      inventory.Remove(itemId);
    }
    else
    {
      inventory[itemId] = remaining;
    }

    return removed;
  }

  private static bool HasStationModules(StationRuntime station, params string[] modules) =>
    modules.All((moduleId) => station.InstalledModules.Contains(moduleId, StringComparer.Ordinal));

  private static bool CanExtractNode(ShipRuntime ship, ResourceNodeRuntime node) =>
    node.ItemId switch
    {
      "ore" => HasShipModules(ship.Definition, "reactor-core", "capacitor-bank", "mining-turret"),
      "gas" => HasShipModules(ship.Definition, "reactor-core", "capacitor-bank", "gas-extractor"),
      _ => false,
    };

  private static float GetShipFuelCapacity(ShipRuntime ship) =>
    CountModules(ship.Definition.Modules, "reactor-core") * ShipFuelPerReactor;

  private static bool NeedsRefuel(ShipRuntime ship) =>
    GetInventoryAmount(ship.Inventory, "fuel") < (GetShipFuelCapacity(ship) * 0.7f);

  private static float ComputeWorkforceRatio(float population, float workforceRequired)
  {
    if (workforceRequired <= 0.01f)
    {
      return 1f;
    }

    var staffedRatio = MathF.Min(1f, population / workforceRequired);
    return 0.1f + (0.9f * staffedRatio);
  }

  private static string? GetStorageRequirement(string storageClass) =>
    storageClass switch
    {
      "bulk-solid" => "bulk-bay",
      "bulk-liquid" => "liquid-tank",
      "bulk-gas" => "gas-tank",
      _ => null,
    };

  private static float TryAddStationInventory(SimulationWorld world, StationRuntime station, string itemId, float amount)
  {
    if (amount <= 0f || !world.ItemDefinitions.TryGetValue(itemId, out var itemDefinition))
    {
      return 0f;
    }

    var storageClass = itemDefinition.Storage;
    var requiredModule = GetStorageRequirement(storageClass);
    if (requiredModule is not null && !station.InstalledModules.Contains(requiredModule, StringComparer.Ordinal))
    {
      return 0f;
    }

    if (!station.Definition.Storage.TryGetValue(storageClass, out var capacity))
    {
      return 0f;
    }

    var used = station.Inventory
      .Where((entry) => world.ItemDefinitions.TryGetValue(entry.Key, out var definition) && definition.Storage == storageClass)
      .Sum((entry) => entry.Value);
    var accepted = MathF.Min(amount, MathF.Max(0f, capacity - used));
    if (accepted <= 0.01f)
    {
      return 0f;
    }

    AddInventory(station.Inventory, itemId, accepted);
    return accepted;
  }

  private static bool CanStartModuleConstruction(StationRuntime station, ModuleRecipeDefinition recipe) =>
    recipe.Inputs.All((input) => GetInventoryAmount(station.Inventory, input.ItemId) + 0.001f >= input.Amount);

  private static ConstructionSiteRuntime? GetConstructionSiteForStation(SimulationWorld world, string stationId) =>
    world.ConstructionSites.FirstOrDefault((site) =>
      string.Equals(site.StationId, stationId, StringComparison.Ordinal)
      && site.State is not ConstructionSiteStateKinds.Completed and not ConstructionSiteStateKinds.Destroyed);

  private static bool IsConstructionSiteReady(ConstructionSiteRuntime site) =>
    site.RequiredItems.All((entry) => GetInventoryAmount(site.DeliveredItems, entry.Key) + 0.001f >= entry.Value);

  private static void UpdateClaims(SimulationWorld world, ICollection<SimulationEventRecord> events)
  {
    foreach (var claim in world.Claims)
    {
      if (claim.State == ClaimStateKinds.Destroyed || claim.Health <= 0f)
      {
        if (claim.State != ClaimStateKinds.Destroyed)
        {
          claim.State = ClaimStateKinds.Destroyed;
          events.Add(new SimulationEventRecord("claim", claim.Id, "claim-destroyed", $"Claim {claim.Id} was destroyed.", world.GeneratedAtUtc));
        }

        foreach (var site in world.ConstructionSites.Where((candidate) => candidate.ClaimId == claim.Id))
        {
          site.State = ConstructionSiteStateKinds.Destroyed;
        }

        continue;
      }

      if (claim.State == ClaimStateKinds.Activating && world.GeneratedAtUtc >= claim.ActivatesAtUtc)
      {
        claim.State = ClaimStateKinds.Active;
        events.Add(new SimulationEventRecord("claim", claim.Id, "claim-activated", $"Claim {claim.Id} is now active.", world.GeneratedAtUtc));
      }
    }
  }

  private static void UpdateConstructionSites(SimulationWorld world, ICollection<SimulationEventRecord> events)
  {
    foreach (var site in world.ConstructionSites)
    {
      if (site.State == ConstructionSiteStateKinds.Destroyed)
      {
        continue;
      }

      var claim = site.ClaimId is null
        ? null
        : world.Claims.FirstOrDefault((candidate) => candidate.Id == site.ClaimId);
      if (claim?.State == ClaimStateKinds.Destroyed)
      {
        site.State = ConstructionSiteStateKinds.Destroyed;
        continue;
      }

      if (claim?.State == ClaimStateKinds.Active && site.State == ConstructionSiteStateKinds.Planned)
      {
        site.State = ConstructionSiteStateKinds.Active;
        events.Add(new SimulationEventRecord("construction-site", site.Id, "site-active", $"Construction site {site.Id} is active.", world.GeneratedAtUtc));
      }

      foreach (var orderId in site.MarketOrderIds)
      {
        var order = world.MarketOrders.FirstOrDefault((candidate) => candidate.Id == orderId);
        if (order is null || !site.RequiredItems.TryGetValue(order.ItemId, out var required))
        {
          continue;
        }

        var remaining = MathF.Max(0f, required - GetInventoryAmount(site.DeliveredItems, order.ItemId));
        order.RemainingAmount = remaining;
        order.State = remaining <= 0.01f
          ? MarketOrderStateKinds.Filled
          : remaining < order.Amount
            ? MarketOrderStateKinds.PartiallyFilled
            : MarketOrderStateKinds.Open;
      }
    }
  }

  private static bool TryEnsureModuleConstructionStarted(StationRuntime station, ModuleRecipeDefinition recipe, string shipId)
  {
    if (station.InstalledModules.Contains(recipe.ModuleId, StringComparer.Ordinal))
    {
      return true;
    }

    if (station.ActiveConstruction is not null)
    {
      return string.Equals(station.ActiveConstruction.ModuleId, recipe.ModuleId, StringComparison.Ordinal)
        && string.Equals(station.ActiveConstruction.AssignedConstructorShipId, shipId, StringComparison.Ordinal);
    }

    if (!CanStartModuleConstruction(station, recipe))
    {
      return false;
    }

    foreach (var input in recipe.Inputs)
    {
      RemoveInventory(station.Inventory, input.ItemId, input.Amount);
    }

    station.ActiveConstruction = new ModuleConstructionRuntime
    {
      ModuleId = recipe.ModuleId,
      RequiredSeconds = recipe.Duration,
      AssignedConstructorShipId = shipId,
    };

    return true;
  }

  private static string? GetNextStationModuleToBuild(StationRuntime station, SimulationWorld world)
  {
    foreach (var moduleId in new[] { "gas-tank", "fuel-processor", "refinery-stack", "dock-bay-small" })
    {
      if (!station.InstalledModules.Contains(moduleId, StringComparer.Ordinal)
        && world.ModuleRecipes.ContainsKey(moduleId))
      {
        return moduleId;
      }
    }

    return null;
  }

  private static void PrepareNextConstructionSiteStep(
    SimulationWorld world,
    StationRuntime station,
    ConstructionSiteRuntime site)
  {
    var nextModuleId = GetNextStationModuleToBuild(station, world);
    foreach (var orderId in site.MarketOrderIds)
    {
      var order = world.MarketOrders.FirstOrDefault((candidate) => candidate.Id == orderId);
      if (order is not null)
      {
        order.State = MarketOrderStateKinds.Cancelled;
        order.RemainingAmount = 0f;
      }
    }

    site.MarketOrderIds.Clear();
    site.Inventory.Clear();
    site.DeliveredItems.Clear();
    site.RequiredItems.Clear();
    site.AssignedConstructorShipIds.Clear();
    site.Progress = 0f;

    if (nextModuleId is null || !world.ModuleRecipes.TryGetValue(nextModuleId, out var recipe))
    {
      site.State = ConstructionSiteStateKinds.Completed;
      site.BlueprintId = null;
      return;
    }

    site.BlueprintId = nextModuleId;
    site.State = ConstructionSiteStateKinds.Active;
    foreach (var input in recipe.Inputs)
    {
      site.RequiredItems[input.ItemId] = input.Amount;
      site.DeliveredItems[input.ItemId] = 0f;
      var orderId = $"market-order-{station.Id}-{nextModuleId}-{input.ItemId}";
      site.MarketOrderIds.Add(orderId);
      station.MarketOrderIds.Add(orderId);
      world.MarketOrders.Add(new MarketOrderRuntime
      {
        Id = orderId,
        FactionId = station.FactionId,
        StationId = station.Id,
        ConstructionSiteId = site.Id,
        Kind = MarketOrderKinds.Buy,
        ItemId = input.ItemId,
        Amount = input.Amount,
        RemainingAmount = input.Amount,
        Valuation = 1f,
        State = MarketOrderStateKinds.Open,
      });
    }
  }

  private static int GetDockingPadCount(StationRuntime station) =>
    CountModules(station.InstalledModules, "dock-bay-small") * 2;

  private static int? ReserveDockingPad(StationRuntime station, string shipId)
  {
    if (station.DockingPadAssignments.FirstOrDefault((entry) => string.Equals(entry.Value, shipId, StringComparison.Ordinal)) is var existing
      && !string.IsNullOrEmpty(existing.Value))
    {
      return existing.Key;
    }

    var padCount = GetDockingPadCount(station);
    for (var padIndex = 0; padIndex < padCount; padIndex += 1)
    {
      if (station.DockingPadAssignments.ContainsKey(padIndex))
      {
        continue;
      }

      station.DockingPadAssignments[padIndex] = shipId;
      return padIndex;
    }

    return null;
  }

  private static void ReleaseDockingPad(StationRuntime station, string shipId)
  {
    var assignment = station.DockingPadAssignments.FirstOrDefault((entry) => string.Equals(entry.Value, shipId, StringComparison.Ordinal));
    if (!string.IsNullOrEmpty(assignment.Value))
    {
      station.DockingPadAssignments.Remove(assignment.Key);
    }
  }

  private static Vector3 GetDockingPadPosition(StationRuntime station, int padIndex)
  {
    var padCount = Math.Max(1, GetDockingPadCount(station));
    var angle = ((MathF.PI * 2f) / padCount) * padIndex;
    var radius = station.Definition.Radius + 14f;
    return new Vector3(
      station.Position.X + (MathF.Cos(angle) * radius),
      station.Position.Y,
      station.Position.Z + (MathF.Sin(angle) * radius));
  }

  private static Vector3 GetDockingHoldPosition(StationRuntime station, string shipId)
  {
    var hash = Math.Abs(shipId.GetHashCode(StringComparison.Ordinal));
    var angle = (hash % 360) * (MathF.PI / 180f);
    var radius = station.Definition.Radius + 34f;
    return new Vector3(
      station.Position.X + (MathF.Cos(angle) * radius),
      station.Position.Y,
      station.Position.Z + (MathF.Sin(angle) * radius));
  }

  private static Vector3 GetUndockTargetPosition(StationRuntime station, int? padIndex, float distance)
  {
    if (padIndex is null)
    {
      return new Vector3(station.Position.X + distance, station.Position.Y, station.Position.Z);
    }

    var pad = GetDockingPadPosition(station, padIndex.Value);
    var dx = pad.X - station.Position.X;
    var dz = pad.Z - station.Position.Z;
    var length = MathF.Sqrt((dx * dx) + (dz * dz));
    if (length <= 0.001f)
    {
      return new Vector3(station.Position.X + distance, station.Position.Y, station.Position.Z);
    }

    var scale = distance / length;
    return new Vector3(
      pad.X + (dx * scale),
      station.Position.Y,
      pad.Z + (dz * scale));
  }

  private static Vector3 GetShipDockedPosition(ShipRuntime ship, StationRuntime station) =>
    ship.AssignedDockingPadIndex is int padIndex
      ? GetDockingPadPosition(station, padIndex)
      : station.Position;

  private static bool AdvanceTimedAction(ShipRuntime ship, float deltaSeconds, float requiredSeconds)
  {
    ship.ActionTimer += deltaSeconds;
    if (ship.ActionTimer < requiredSeconds)
    {
      return false;
    }

    ship.ActionTimer = 0f;
    return true;
  }

  private static float GetShipCargoAmount(ShipRuntime ship)
  {
    var cargoItemId = ship.Definition.CargoItemId;
    return cargoItemId is null ? 0f : GetInventoryAmount(ship.Inventory, cargoItemId);
  }

  private static CommanderRuntime? GetShipCommander(SimulationWorld world, ShipRuntime ship) =>
    ship.CommanderId is null
      ? null
      : world.Commanders.FirstOrDefault((candidate) => candidate.Id == ship.CommanderId && candidate.Kind == CommanderKind.Ship);

  private static void SyncCommanderToShip(ShipRuntime ship, CommanderRuntime commander)
  {
    if (commander.ActiveBehavior is not null)
    {
      ship.DefaultBehavior.Kind = commander.ActiveBehavior.Kind;
      ship.DefaultBehavior.AreaSystemId = commander.ActiveBehavior.AreaSystemId;
      ship.DefaultBehavior.ModuleId = commander.ActiveBehavior.ModuleId;
      ship.DefaultBehavior.NodeId = commander.ActiveBehavior.NodeId;
      ship.DefaultBehavior.Phase = commander.ActiveBehavior.Phase;
      ship.DefaultBehavior.PatrolIndex = commander.ActiveBehavior.PatrolIndex;
      ship.DefaultBehavior.StationId = commander.ActiveBehavior.StationId;
    }

    if (commander.ActiveOrder is null)
    {
      ship.Order = null;
    }
    else
    {
      ship.Order = new ShipOrderRuntime
      {
        Kind = commander.ActiveOrder.Kind,
        Status = commander.ActiveOrder.Status,
        DestinationSystemId = commander.ActiveOrder.DestinationSystemId,
        DestinationPosition = commander.ActiveOrder.DestinationPosition,
      };
    }

    if (commander.ActiveTask is not null)
    {
      ship.ControllerTask = new ControllerTaskRuntime
      {
        Kind = commander.ActiveTask.Kind,
        Status = commander.ActiveTask.Status,
        CommanderId = commander.Id,
        TargetEntityId = commander.ActiveTask.TargetEntityId,
        TargetNodeId = commander.ActiveTask.TargetNodeId,
        TargetPosition = commander.ActiveTask.TargetPosition,
        TargetSystemId = commander.ActiveTask.TargetSystemId,
        Threshold = commander.ActiveTask.Threshold,
      };
    }
  }

  private static void SyncShipToCommander(ShipRuntime ship, CommanderRuntime commander)
  {
    commander.ActiveBehavior ??= new CommanderBehaviorRuntime { Kind = ship.DefaultBehavior.Kind };
    commander.ActiveBehavior.Kind = ship.DefaultBehavior.Kind;
    commander.ActiveBehavior.AreaSystemId = ship.DefaultBehavior.AreaSystemId;
    commander.ActiveBehavior.ModuleId = ship.DefaultBehavior.ModuleId;
    commander.ActiveBehavior.NodeId = ship.DefaultBehavior.NodeId;
    commander.ActiveBehavior.Phase = ship.DefaultBehavior.Phase;
    commander.ActiveBehavior.PatrolIndex = ship.DefaultBehavior.PatrolIndex;
    commander.ActiveBehavior.StationId = ship.DefaultBehavior.StationId;

    if (ship.Order is null)
    {
      commander.ActiveOrder = null;
    }
    else
    {
      commander.ActiveOrder ??= new CommanderOrderRuntime
      {
        Kind = ship.Order.Kind,
        DestinationSystemId = ship.Order.DestinationSystemId,
        DestinationPosition = ship.Order.DestinationPosition,
      };
      commander.ActiveOrder.Status = ship.Order.Status;
      commander.ActiveOrder.TargetEntityId = ship.ControllerTask.TargetEntityId;
      commander.ActiveOrder.DestinationNodeId = ship.ControllerTask.TargetNodeId ?? ship.SpatialState.DestinationNodeId;
    }

    commander.ActiveTask ??= new CommanderTaskRuntime { Kind = ship.ControllerTask.Kind };
    commander.ActiveTask.Kind = ship.ControllerTask.Kind;
    commander.ActiveTask.Status = ship.ControllerTask.Status;
    commander.ActiveTask.TargetEntityId = ship.ControllerTask.TargetEntityId;
    commander.ActiveTask.TargetNodeId = ship.ControllerTask.TargetNodeId;
    commander.ActiveTask.TargetPosition = ship.ControllerTask.TargetPosition;
    commander.ActiveTask.TargetSystemId = ship.ControllerTask.TargetSystemId;
    commander.ActiveTask.Threshold = ship.ControllerTask.Threshold;
  }

  private void RefreshControlLayers(ShipRuntime ship, SimulationWorld world)
  {
    var commander = GetShipCommander(world, ship);
    if (commander is not null)
    {
      SyncCommanderToShip(ship, commander);
    }

    if (ship.Order is not null && ship.Order.Status == "queued")
    {
      ship.Order.Status = "accepted";
      if (commander?.ActiveOrder is not null)
      {
        commander.ActiveOrder.Status = ship.Order.Status;
      }
    }

    if (commander is not null)
    {
      SyncShipToCommander(ship, commander);
    }
  }

  private void PlanControllerTask(ShipRuntime ship, SimulationWorld world)
  {
    var commander = GetShipCommander(world, ship);
    if (ship.Order is not null)
    {
      var plannedTask = new ControllerTaskRuntime
      {
        Kind = "travel",
        Status = "active",
        CommanderId = commander?.Id,
        TargetEntityId = null,
        TargetSystemId = ship.Order.DestinationSystemId,
        TargetNodeId = ship.SpatialState.DestinationNodeId,
        TargetPosition = ship.Order.DestinationPosition,
        Threshold = world.Balance.ArrivalThreshold,
      };
      ship.ControllerTask = plannedTask;
      if (commander is not null)
      {
        commander.ActiveTask = new CommanderTaskRuntime
        {
          Kind = plannedTask.Kind,
          Status = plannedTask.Status,
          TargetEntityId = plannedTask.TargetEntityId,
          TargetNodeId = plannedTask.TargetNodeId,
          TargetPosition = plannedTask.TargetPosition,
          TargetSystemId = plannedTask.TargetSystemId,
          Threshold = plannedTask.Threshold,
        };
      }
      return;
    }

    if (ship.DefaultBehavior.Kind == "auto-mine")
    {
      PlanResourceHarvest(ship, world, "ore", "mining-turret");
      return;
    }

    if (ship.DefaultBehavior.Kind == "auto-harvest-gas")
    {
      PlanResourceHarvest(ship, world, "gas", "gas-extractor");
      return;
    }

    if (ship.DefaultBehavior.Kind == "construct-station")
    {
      PlanStationConstruction(ship, world);
      return;
    }

    if (ship.DefaultBehavior.Kind == "patrol" && ship.DefaultBehavior.PatrolPoints.Count > 0)
    {
      ship.ControllerTask = new ControllerTaskRuntime
      {
        Kind = "travel",
        TargetPosition = ship.DefaultBehavior.PatrolPoints[ship.DefaultBehavior.PatrolIndex],
        TargetSystemId = ship.SystemId,
        Threshold = 18f,
      };
      return;
    }

    ship.ControllerTask = new ControllerTaskRuntime
    {
      Kind = "idle",
      Threshold = world.Balance.ArrivalThreshold,
    };
  }

  private void PlanResourceHarvest(ShipRuntime ship, SimulationWorld world, string resourceItemId, string requiredModule)
  {
    var behavior = ship.DefaultBehavior;
    var refinery = SelectBestBuyStation(world, ship, resourceItemId, behavior.StationId);
    behavior.StationId = refinery?.Id;
    var node = behavior.NodeId is null
      ? world.Nodes
        .Where((candidate) => (behavior.AreaSystemId is null || candidate.SystemId == behavior.AreaSystemId) && candidate.ItemId == resourceItemId)
        .OrderByDescending((candidate) => candidate.OreRemaining)
        .FirstOrDefault()
      : world.Nodes.FirstOrDefault((candidate) => candidate.Id == behavior.NodeId);

    if (refinery is null || node is null || !HasShipModules(ship.Definition, "reactor-core", "capacitor-bank", requiredModule))
    {
      behavior.Kind = "idle";
      ship.ControllerTask = new ControllerTaskRuntime { Kind = "idle", Threshold = world.Balance.ArrivalThreshold };
      return;
    }

    behavior.NodeId ??= node.Id;
    if (ship.DockedStationId == refinery.Id)
    {
      if (GetShipCargoAmount(ship) > 0.01f)
      {
        behavior.Phase = "unload";
      }
      else if (NeedsRefuel(ship))
      {
        behavior.Phase = "refuel";
      }
      else if (behavior.Phase is "dock" or "unload" or "refuel")
      {
        behavior.Phase = "undock";
      }
    }
    else if (NeedsRefuel(ship) && behavior.Phase is not "travel-to-station" and not "dock")
    {
      behavior.Phase = "travel-to-station";
    }

    switch (behavior.Phase)
    {
      case "extract":
        ship.ControllerTask = new ControllerTaskRuntime
        {
          Kind = "extract",
          TargetEntityId = node.Id,
          TargetSystemId = node.SystemId,
          TargetPosition = node.Position,
          Threshold = 14f,
        };
        break;
      case "travel-to-station":
        ship.ControllerTask = new ControllerTaskRuntime
        {
          Kind = "travel",
          TargetEntityId = refinery.Id,
          TargetSystemId = refinery.SystemId,
          TargetPosition = refinery.Position,
          Threshold = refinery.Definition.Radius + 8f,
        };
        break;
      case "dock":
        ship.ControllerTask = new ControllerTaskRuntime
        {
          Kind = "dock",
          TargetEntityId = refinery.Id,
          TargetSystemId = refinery.SystemId,
          TargetPosition = refinery.Position,
          Threshold = refinery.Definition.Radius + 4f,
        };
        break;
      case "unload":
        ship.ControllerTask = new ControllerTaskRuntime
        {
          Kind = "unload",
          TargetEntityId = refinery.Id,
          TargetSystemId = refinery.SystemId,
          TargetPosition = refinery.Position,
          Threshold = 0f,
        };
        break;
      case "refuel":
        ship.ControllerTask = new ControllerTaskRuntime
        {
          Kind = "refuel",
          TargetEntityId = refinery.Id,
          TargetSystemId = refinery.SystemId,
          TargetPosition = refinery.Position,
          Threshold = 0f,
        };
        break;
      case "undock":
        ship.ControllerTask = new ControllerTaskRuntime
        {
          Kind = "undock",
          TargetEntityId = refinery.Id,
          TargetSystemId = refinery.SystemId,
          TargetPosition = new Vector3(refinery.Position.X + world.Balance.UndockDistance, refinery.Position.Y, refinery.Position.Z),
          Threshold = 8f,
        };
        break;
      default:
        ship.ControllerTask = new ControllerTaskRuntime
        {
          Kind = "travel",
          TargetEntityId = node.Id,
          TargetSystemId = node.SystemId,
          TargetPosition = node.Position,
          Threshold = 18f,
        };
        behavior.Phase = "travel-to-node";
        break;
    }
  }

  private static StationRuntime? SelectBestBuyStation(SimulationWorld world, ShipRuntime ship, string itemId, string? preferredStationId)
  {
    var preferred = preferredStationId is null
      ? null
      : world.Stations.FirstOrDefault((station) => station.Id == preferredStationId);

    var bestOrder = world.MarketOrders
      .Where((order) =>
        order.Kind == MarketOrderKinds.Buy &&
        order.ConstructionSiteId is null &&
        order.State != MarketOrderStateKinds.Cancelled &&
        order.ItemId == itemId &&
        order.RemainingAmount > 0.01f)
      .Select((order) => (Order: order, Station: world.Stations.FirstOrDefault((station) => station.Id == order.StationId)))
      .Where((entry) => entry.Station is not null)
      .OrderByDescending((entry) =>
      {
        var distancePenalty = entry.Station!.SystemId == ship.SystemId ? 0f : 0.2f;
        return entry.Order.Valuation - distancePenalty;
      })
      .FirstOrDefault();

    return bestOrder.Station ?? preferred;
  }

  private void PlanStationConstruction(ShipRuntime ship, SimulationWorld world)
  {
    var behavior = ship.DefaultBehavior;
    var station = world.Stations.FirstOrDefault((candidate) => candidate.Id == behavior.StationId);
    var site = station is null ? null : GetConstructionSiteForStation(world, station.Id);
    if (station is null)
    {
      behavior.Kind = "idle";
      ship.ControllerTask = new ControllerTaskRuntime { Kind = "idle", Threshold = world.Balance.ArrivalThreshold };
      return;
    }

    var moduleId = site?.BlueprintId ?? GetNextStationModuleToBuild(station, world);
    behavior.ModuleId = moduleId;
    if (moduleId is null)
    {
      ship.ControllerTask = new ControllerTaskRuntime { Kind = "idle", Threshold = world.Balance.ArrivalThreshold };
      return;
    }

    if (ship.DockedStationId == station.Id)
    {
      if (NeedsRefuel(ship))
      {
        behavior.Phase = "refuel";
      }
      else if (site is not null && site.State == ConstructionSiteStateKinds.Active && !IsConstructionSiteReady(site))
      {
        behavior.Phase = "deliver-to-site";
      }
      else if (site is not null && site.State == ConstructionSiteStateKinds.Active && IsConstructionSiteReady(site))
      {
        behavior.Phase = "build-site";
      }
      else if (site is not null)
      {
        behavior.Phase = "wait-for-materials";
      }
      else if (CanStartModuleConstruction(station, world.ModuleRecipes[moduleId]))
      {
        behavior.Phase = "construct-module";
      }
      else
      {
        behavior.Phase = "wait-for-materials";
      }
    }
    else if (behavior.Phase is not "travel-to-station" and not "dock")
    {
      behavior.Phase = "travel-to-station";
    }

    switch (behavior.Phase)
    {
      case "dock":
        ship.ControllerTask = new ControllerTaskRuntime
        {
          Kind = "dock",
          TargetEntityId = station.Id,
          TargetSystemId = station.SystemId,
          TargetPosition = station.Position,
          Threshold = station.Definition.Radius + 4f,
        };
        break;
      case "refuel":
        ship.ControllerTask = new ControllerTaskRuntime
        {
          Kind = "refuel",
          TargetEntityId = station.Id,
          TargetSystemId = station.SystemId,
          TargetPosition = station.Position,
          Threshold = 0f,
        };
        break;
      case "construct-module":
        ship.ControllerTask = new ControllerTaskRuntime
        {
          Kind = "construct-module",
          TargetEntityId = station.Id,
          TargetSystemId = station.SystemId,
          TargetPosition = station.Position,
          Threshold = 0f,
        };
        break;
      case "deliver-to-site":
        ship.ControllerTask = new ControllerTaskRuntime
        {
          Kind = "deliver-construction",
          TargetEntityId = site?.Id,
          TargetSystemId = station.SystemId,
          TargetPosition = station.Position,
          Threshold = 0f,
        };
        break;
      case "build-site":
        ship.ControllerTask = new ControllerTaskRuntime
        {
          Kind = "build-construction-site",
          TargetEntityId = site?.Id,
          TargetSystemId = station.SystemId,
          TargetPosition = station.Position,
          Threshold = 0f,
        };
        break;
      case "wait-for-materials":
        ship.ControllerTask = new ControllerTaskRuntime
        {
          Kind = "idle",
          TargetEntityId = station.Id,
          TargetSystemId = station.SystemId,
          TargetPosition = station.Position,
          Threshold = 0f,
        };
        break;
      default:
        ship.ControllerTask = new ControllerTaskRuntime
        {
          Kind = "travel",
          TargetEntityId = station.Id,
          TargetSystemId = station.SystemId,
          TargetPosition = station.Position,
          Threshold = station.Definition.Radius + 8f,
        };
        behavior.Phase = "travel-to-station";
        break;
    }
  }

  private string UpdateControllerTask(ShipRuntime ship, SimulationWorld world, float deltaSeconds)
  {
    var task = ship.ControllerTask;
    switch (task.Kind)
    {
      case "idle":
        TryConsumeShipEnergy(ship, world.Balance.Energy.IdleDrain * deltaSeconds);
        ship.State = "idle";
        ship.TargetPosition = ship.Position;
        return "none";
      case "travel":
        return UpdateTravel(ship, world, deltaSeconds);
      case "extract":
        return UpdateExtract(ship, world, deltaSeconds);
      case "dock":
        return UpdateDock(ship, world, deltaSeconds);
      case "unload":
        return UpdateUnload(ship, world, deltaSeconds);
      case "refuel":
        return UpdateRefuel(ship, world, deltaSeconds);
      case "deliver-construction":
        return UpdateDeliverConstruction(ship, world, deltaSeconds);
      case "build-construction-site":
        return UpdateBuildConstructionSite(ship, world, deltaSeconds);
      case "load-workers":
        return UpdateLoadWorkers(ship, world, deltaSeconds);
      case "unload-workers":
        return UpdateUnloadWorkers(ship, world, deltaSeconds);
      case "construct-module":
        return UpdateConstructModule(ship, world, deltaSeconds);
      case "undock":
        return UpdateUndock(ship, world, deltaSeconds);
      default:
        ship.State = "idle";
        ship.TargetPosition = ship.Position;
        return "none";
    }
  }

  private string UpdateTravel(ShipRuntime ship, SimulationWorld world, float deltaSeconds)
  {
    var task = ship.ControllerTask;
    if (task.TargetPosition is null || task.TargetSystemId is null)
    {
      ship.State = "idle";
      ship.TargetPosition = ship.Position;
      return "none";
    }

    var targetPosition = task.TargetPosition.Value;
    var targetNode = ResolveTravelTargetNode(world, task, targetPosition);
    ship.TargetPosition = targetPosition;

    if (ship.SystemId != task.TargetSystemId)
    {
      return UpdateFtlTransit(ship, world, deltaSeconds, task.TargetSystemId, targetPosition, targetNode);
    }

    var currentNode = ResolveCurrentNode(world, ship);
    if (targetNode is not null && currentNode is not null && !string.Equals(currentNode.Id, targetNode.Id, StringComparison.Ordinal))
    {
      return UpdateWarpTransit(ship, world, deltaSeconds, targetPosition, targetNode);
    }

    return UpdateLocalTravel(ship, world, deltaSeconds, task.TargetSystemId, targetPosition, targetNode, task.Threshold);
  }

  private static NodeRuntime? ResolveTravelTargetNode(SimulationWorld world, ControllerTaskRuntime task, Vector3 targetPosition)
  {
    if (!string.IsNullOrWhiteSpace(task.TargetEntityId))
    {
      var station = world.Stations.FirstOrDefault((candidate) => candidate.Id == task.TargetEntityId);
      if (station?.NodeId is not null)
      {
        return world.SpatialNodes.FirstOrDefault((candidate) => candidate.Id == station.NodeId);
      }

      var node = world.SpatialNodes.FirstOrDefault((candidate) => candidate.Id == task.TargetEntityId);
      if (node is not null)
      {
        return node;
      }
    }

    return world.SpatialNodes
      .Where((candidate) => task.TargetSystemId is null || candidate.SystemId == task.TargetSystemId)
      .OrderBy((candidate) => candidate.Position.DistanceTo(targetPosition))
      .FirstOrDefault();
  }

  private static NodeRuntime? ResolveCurrentNode(SimulationWorld world, ShipRuntime ship)
  {
    if (ship.SpatialState.CurrentNodeId is not null)
    {
      return world.SpatialNodes.FirstOrDefault((candidate) => candidate.Id == ship.SpatialState.CurrentNodeId);
    }

    return world.SpatialNodes
      .Where((candidate) => candidate.SystemId == ship.SystemId)
      .OrderBy((candidate) => candidate.Position.DistanceTo(ship.Position))
      .FirstOrDefault();
  }

  private string UpdateLocalTravel(
    ShipRuntime ship,
    SimulationWorld world,
    float deltaSeconds,
    string targetSystemId,
    Vector3 targetPosition,
    NodeRuntime? targetNode,
    float threshold)
  {
    var distance = ship.Position.DistanceTo(targetPosition);
    ship.SpatialState.SpaceLayer = SpaceLayerKinds.LocalSpace;
    ship.SpatialState.MovementRegime = MovementRegimeKinds.LocalFlight;
    ship.SpatialState.Transit = null;
    ship.SpatialState.DestinationNodeId = targetNode?.Id;

    if (distance <= threshold)
    {
      ship.ActionTimer = 0f;
      TryConsumeShipEnergy(ship, world.Balance.Energy.IdleDrain * deltaSeconds);
      ship.Position = targetPosition;
      ship.TargetPosition = ship.Position;
      ship.SystemId = targetSystemId;
      ship.SpatialState.CurrentNodeId = targetNode?.Id;
      ship.SpatialState.CurrentBubbleId = targetNode?.BubbleId;
      ship.State = "arriving";
      return "arrived";
    }

    if (!TryConsumeShipEnergy(ship, world.Balance.Energy.MoveDrain * deltaSeconds))
    {
      ship.State = "power-starved";
      ship.TargetPosition = ship.Position;
      return "none";
    }

    ship.ActionTimer = 0f;
    ship.State = "local-flight";
    ship.Position = ship.Position.MoveToward(targetPosition, ship.Definition.Speed * deltaSeconds);
    return "none";
  }

  private string UpdateWarpTransit(
    ShipRuntime ship,
    SimulationWorld world,
    float deltaSeconds,
    Vector3 targetPosition,
    NodeRuntime targetNode)
  {
    var transit = ship.SpatialState.Transit;
    if (transit is null || transit.Regime != MovementRegimeKinds.Warp || transit.DestinationNodeId != targetNode.Id)
    {
      transit = new ShipTransitRuntime
      {
        Regime = MovementRegimeKinds.Warp,
        OriginNodeId = ship.SpatialState.CurrentNodeId,
        DestinationNodeId = targetNode.Id,
        StartedAtUtc = world.GeneratedAtUtc,
      };
      ship.SpatialState.Transit = transit;
    }

    ship.SpatialState.SpaceLayer = SpaceLayerKinds.SystemSpace;
    ship.SpatialState.MovementRegime = MovementRegimeKinds.Warp;
    ship.SpatialState.CurrentNodeId = null;
    ship.SpatialState.CurrentBubbleId = null;
    ship.SpatialState.DestinationNodeId = targetNode.Id;

    var spoolDuration = MathF.Max(0.4f, ship.Definition.SpoolTime * 0.5f);
    if (ship.State != "warping")
    {
      if (ship.State != "spooling-warp")
      {
        ship.ActionTimer = 0f;
      }

      if (!TryConsumeShipEnergy(ship, world.Balance.Energy.IdleDrain * deltaSeconds))
      {
        ship.State = "power-starved";
        ship.TargetPosition = ship.Position;
        return "none";
      }

      ship.State = "spooling-warp";
      if (!AdvanceTimedAction(ship, deltaSeconds, spoolDuration))
      {
        return "none";
      }

      ship.State = "warping";
    }

    if (!TryConsumeShipEnergy(ship, world.Balance.Energy.WarpDrain * deltaSeconds))
    {
      ship.State = "power-starved";
      ship.TargetPosition = ship.Position;
      return "none";
    }

    var totalDistance = MathF.Max(0.001f, transit.OriginNodeId is null
      ? ship.Position.DistanceTo(targetPosition)
      : (world.SpatialNodes.FirstOrDefault((candidate) => candidate.Id == transit.OriginNodeId)?.Position.DistanceTo(targetPosition) ?? ship.Position.DistanceTo(targetPosition)));
    ship.Position = ship.Position.MoveToward(targetPosition, ship.Definition.Speed * deltaSeconds);
    transit.Progress = MathF.Min(1f, 1f - (ship.Position.DistanceTo(targetPosition) / totalDistance));
    return ship.Position.DistanceTo(targetPosition) <= 18f
      ? CompleteTransitArrival(ship, targetNode.SystemId, targetPosition, targetNode)
      : "none";
  }

  private string UpdateFtlTransit(
    ShipRuntime ship,
    SimulationWorld world,
    float deltaSeconds,
    string targetSystemId,
    Vector3 targetPosition,
    NodeRuntime? targetNode)
  {
    var destinationNodeId = targetNode?.Id;
    var transit = ship.SpatialState.Transit;
    if (transit is null || transit.Regime != MovementRegimeKinds.FtlTransit || transit.DestinationNodeId != destinationNodeId)
    {
      transit = new ShipTransitRuntime
      {
        Regime = MovementRegimeKinds.FtlTransit,
        OriginNodeId = ship.SpatialState.CurrentNodeId,
        DestinationNodeId = destinationNodeId,
        StartedAtUtc = world.GeneratedAtUtc,
      };
      ship.SpatialState.Transit = transit;
    }

    ship.SpatialState.SpaceLayer = SpaceLayerKinds.GalaxySpace;
    ship.SpatialState.MovementRegime = MovementRegimeKinds.FtlTransit;
    ship.SpatialState.CurrentNodeId = null;
    ship.SpatialState.CurrentBubbleId = null;
    ship.SpatialState.DestinationNodeId = destinationNodeId;

    if (ship.State != "ftl")
    {
      if (ship.State != "spooling-ftl")
      {
        ship.ActionTimer = 0f;
      }

      if (!TryConsumeShipEnergy(ship, world.Balance.Energy.IdleDrain * deltaSeconds))
      {
        ship.State = "power-starved";
        ship.TargetPosition = ship.Position;
        return "none";
      }

      ship.State = "spooling-ftl";
      if (!AdvanceTimedAction(ship, deltaSeconds, ship.Definition.SpoolTime))
      {
        return "none";
      }

      ship.State = "ftl";
    }

    if (!TryConsumeShipEnergy(ship, world.Balance.Energy.WarpDrain * deltaSeconds))
    {
      ship.State = "power-starved";
      ship.TargetPosition = ship.Position;
      return "none";
    }

    var totalDistance = MathF.Max(0.001f, ship.Position.DistanceTo(targetPosition));
    ship.Position = ship.Position.MoveToward(targetPosition, ship.Definition.FtlSpeed * deltaSeconds);
    transit.Progress = MathF.Min(1f, 1f - (ship.Position.DistanceTo(targetPosition) / totalDistance));
    return ship.Position.DistanceTo(targetPosition) <= 24f
      ? CompleteTransitArrival(ship, targetSystemId, targetPosition, targetNode)
      : "none";
  }

  private static string CompleteTransitArrival(ShipRuntime ship, string targetSystemId, Vector3 targetPosition, NodeRuntime? targetNode)
  {
    ship.ActionTimer = 0f;
    ship.Position = targetPosition;
    ship.TargetPosition = targetPosition;
    ship.SystemId = targetSystemId;
    ship.SpatialState.Transit = null;
    ship.SpatialState.SpaceLayer = SpaceLayerKinds.LocalSpace;
    ship.SpatialState.MovementRegime = MovementRegimeKinds.LocalFlight;
    ship.SpatialState.CurrentNodeId = targetNode?.Id;
    ship.SpatialState.CurrentBubbleId = targetNode?.BubbleId;
    ship.SpatialState.DestinationNodeId = targetNode?.Id;
    ship.State = "arriving";
    return "arrived";
  }

  private string UpdateExtract(ShipRuntime ship, SimulationWorld world, float deltaSeconds)
  {
    var task = ship.ControllerTask;
    var node = world.Nodes.FirstOrDefault((candidate) => candidate.Id == task.TargetEntityId);
    if (node is null || task.TargetPosition is null || !CanExtractNode(ship, node))
    {
      ship.State = "idle";
      ship.TargetPosition = ship.Position;
      return "none";
    }

    ship.TargetPosition = task.TargetPosition.Value;
    var distance = ship.Position.DistanceTo(task.TargetPosition.Value);
    if (distance > task.Threshold)
    {
      ship.ActionTimer = 0f;
      if (!TryConsumeShipEnergy(ship, world.Balance.Energy.MoveDrain * deltaSeconds))
      {
        ship.State = "power-starved";
        ship.TargetPosition = ship.Position;
        return "none";
      }

      ship.State = "mining-approach";
      ship.Position = ship.Position.MoveToward(task.TargetPosition.Value, ship.Definition.Speed * deltaSeconds);
      return "none";
    }

    if (!TryConsumeShipEnergy(ship, world.Balance.Energy.MoveDrain * deltaSeconds))
    {
      ship.State = "power-starved";
      ship.TargetPosition = ship.Position;
      return "none";
    }

    ship.State = "mining";
    if (!AdvanceTimedAction(ship, deltaSeconds, world.Balance.MiningCycleSeconds))
    {
      return "none";
    }

    var cargoAmount = GetShipCargoAmount(ship);
    var mined = MathF.Min(world.Balance.MiningRate, ship.Definition.CargoCapacity - cargoAmount);
    mined = MathF.Min(mined, node.OreRemaining);
    if (ship.Definition.CargoItemId is not null)
    {
      AddInventory(ship.Inventory, ship.Definition.CargoItemId, mined);
    }
    node.OreRemaining -= mined;
    if (node.OreRemaining <= 0f)
    {
      node.OreRemaining = node.MaxOre;
    }

    return GetShipCargoAmount(ship) >= ship.Definition.CargoCapacity ? "cargo-full" : "none";
  }

  private string UpdateDock(ShipRuntime ship, SimulationWorld world, float deltaSeconds)
  {
    var task = ship.ControllerTask;
    var station = world.Stations.FirstOrDefault((candidate) => candidate.Id == task.TargetEntityId);
    if (station is null || task.TargetPosition is null)
    {
      ship.State = "idle";
      ship.TargetPosition = ship.Position;
      return "none";
    }

    var padIndex = ship.AssignedDockingPadIndex ?? ReserveDockingPad(station, ship.Id);
    if (padIndex is null)
    {
      ship.ActionTimer = 0f;
      ship.State = "awaiting-dock";
      ship.TargetPosition = GetDockingHoldPosition(station, ship.Id);
      var waitDistance = ship.Position.DistanceTo(ship.TargetPosition);
      if (waitDistance > 4f && TryConsumeShipEnergy(ship, world.Balance.Energy.MoveDrain * deltaSeconds))
      {
        ship.Position = ship.Position.MoveToward(ship.TargetPosition, ship.Definition.Speed * deltaSeconds);
      }

      return "none";
    }

    ship.AssignedDockingPadIndex = padIndex;
    var padPosition = GetDockingPadPosition(station, padIndex.Value);
    ship.TargetPosition = padPosition;
    var distance = ship.Position.DistanceTo(padPosition);
    if (distance > 4f)
    {
      ship.ActionTimer = 0f;
      if (!TryConsumeShipEnergy(ship, world.Balance.Energy.MoveDrain * deltaSeconds))
      {
        ship.State = "power-starved";
        ship.TargetPosition = ship.Position;
        return "none";
      }

      ship.State = "docking-approach";
      ship.Position = ship.Position.MoveToward(padPosition, ship.Definition.Speed * deltaSeconds);
      return "none";
    }

    if (!TryConsumeShipEnergy(ship, world.Balance.Energy.MoveDrain * deltaSeconds))
    {
      ship.State = "power-starved";
      ship.TargetPosition = ship.Position;
      return "none";
    }

    if (!TryConsumeStationEnergy(station, world.Balance.Energy.IdleDrain * deltaSeconds))
    {
      ship.State = "power-starved";
      ship.TargetPosition = ship.Position;
      return "none";
    }

    ship.State = "docking";
    if (!AdvanceTimedAction(ship, deltaSeconds, world.Balance.DockingDuration))
    {
      return "none";
    }

    ship.State = "docked";
    ship.DockedStationId = station.Id;
    station.DockedShipIds.Add(ship.Id);
    ship.Position = padPosition;
    ship.TargetPosition = padPosition;
    return "docked";
  }

  private string UpdateUnload(ShipRuntime ship, SimulationWorld world, float deltaSeconds)
  {
    if (ship.DockedStationId is null)
    {
      ship.State = "idle";
      ship.TargetPosition = ship.Position;
      return "none";
    }

    var station = world.Stations.FirstOrDefault((candidate) => candidate.Id == ship.DockedStationId);
    if (station is null)
    {
      ship.DockedStationId = null;
      ship.AssignedDockingPadIndex = null;
      ship.State = "idle";
      ship.TargetPosition = ship.Position;
      return "none";
    }

    if (!TryConsumeShipEnergy(ship, world.Balance.Energy.IdleDrain * deltaSeconds)
      || !TryConsumeStationEnergy(station, world.Balance.Energy.IdleDrain * deltaSeconds))
    {
      ship.State = "power-starved";
      ship.TargetPosition = ship.Position;
      return "none";
    }

    ship.TargetPosition = GetShipDockedPosition(ship, station);
    ship.Position = ship.TargetPosition;
    ship.ActionTimer = 0f;
    ship.State = "transferring";
    var cargoItemId = ship.Definition.CargoItemId;
    var moved = cargoItemId is null ? 0f : MathF.Min(GetInventoryAmount(ship.Inventory, cargoItemId), world.Balance.TransferRate * deltaSeconds);
    if (cargoItemId is not null)
    {
      var accepted = TryAddStationInventory(world, station, cargoItemId, moved);
      RemoveInventory(ship.Inventory, cargoItemId, accepted);
      moved = accepted;
    }
    var faction = world.Factions.FirstOrDefault((candidate) => candidate.Id == ship.FactionId);
    if (faction is not null && cargoItemId == "ore")
    {
      faction.OreMined += moved;
      faction.Credits += moved * 0.4f;
    }

    return cargoItemId is null || GetInventoryAmount(ship.Inventory, cargoItemId) <= 0.01f ? "unloaded" : "none";
  }

  private string UpdateRefuel(ShipRuntime ship, SimulationWorld world, float deltaSeconds)
  {
    if (ship.DockedStationId is null)
    {
      ship.State = "idle";
      ship.TargetPosition = ship.Position;
      return "none";
    }

    var station = world.Stations.FirstOrDefault((candidate) => candidate.Id == ship.DockedStationId);
    if (station is null)
    {
      ship.DockedStationId = null;
      ship.AssignedDockingPadIndex = null;
      ship.State = "idle";
      ship.TargetPosition = ship.Position;
      return "none";
    }

    if (!TryConsumeShipEnergy(ship, world.Balance.Energy.IdleDrain * deltaSeconds)
      || !TryConsumeStationEnergy(station, world.Balance.Energy.IdleDrain * deltaSeconds))
    {
      ship.State = "power-starved";
      ship.TargetPosition = ship.Position;
      return "none";
    }

    ship.TargetPosition = GetShipDockedPosition(ship, station);
    ship.Position = ship.TargetPosition;
    ship.ActionTimer = 0f;
    ship.State = "refueling";
    var transfer = MathF.Min(world.Balance.TransferRate * deltaSeconds, GetShipFuelCapacity(ship) - GetInventoryAmount(ship.Inventory, "fuel"));
    var moved = MathF.Min(transfer, GetInventoryAmount(station.Inventory, "fuel"));
    if (moved > 0.01f)
    {
      RemoveInventory(station.Inventory, "fuel", moved);
      AddInventory(ship.Inventory, "fuel", moved);
    }

    return !NeedsRefuel(ship) ? "refueled" : "none";
  }

  private string UpdateConstructModule(ShipRuntime ship, SimulationWorld world, float deltaSeconds)
  {
    if (ship.DockedStationId is null || ship.DefaultBehavior.ModuleId is null)
    {
      ship.State = "idle";
      ship.TargetPosition = ship.Position;
      return "none";
    }

    var station = world.Stations.FirstOrDefault((candidate) => candidate.Id == ship.DockedStationId);
    if (station is null || !world.ModuleRecipes.TryGetValue(ship.DefaultBehavior.ModuleId, out var recipe))
    {
      ship.AssignedDockingPadIndex = null;
      ship.State = "idle";
      ship.TargetPosition = ship.Position;
      return "none";
    }

    if (!TryConsumeShipEnergy(ship, world.Balance.Energy.IdleDrain * deltaSeconds)
      || !TryConsumeStationEnergy(station, world.Balance.Energy.MoveDrain * deltaSeconds))
    {
      ship.State = "power-starved";
      ship.TargetPosition = ship.Position;
      return "none";
    }

    if (!TryEnsureModuleConstructionStarted(station, recipe, ship.Id))
    {
      ship.ActionTimer = 0f;
      ship.State = "waiting-materials";
      ship.TargetPosition = GetShipDockedPosition(ship, station);
      return "none";
    }

    if (station.ActiveConstruction?.AssignedConstructorShipId != ship.Id)
    {
      ship.State = "construction-blocked";
      ship.TargetPosition = GetShipDockedPosition(ship, station);
      return "none";
    }

    ship.TargetPosition = GetShipDockedPosition(ship, station);
    ship.Position = ship.TargetPosition;
    ship.ActionTimer = 0f;
    ship.State = "constructing";
    station.ActiveConstruction.ProgressSeconds += deltaSeconds;
    if (station.ActiveConstruction.ProgressSeconds < station.ActiveConstruction.RequiredSeconds)
    {
      return "none";
    }

    station.InstalledModules.Add(station.ActiveConstruction.ModuleId);
    station.ActiveConstruction = null;
    return "module-constructed";
  }

  private string UpdateDeliverConstruction(ShipRuntime ship, SimulationWorld world, float deltaSeconds)
  {
    if (ship.DockedStationId is null)
    {
      ship.State = "idle";
      ship.TargetPosition = ship.Position;
      return "none";
    }

    var station = world.Stations.FirstOrDefault((candidate) => candidate.Id == ship.DockedStationId);
    var site = world.ConstructionSites.FirstOrDefault((candidate) => candidate.Id == ship.ControllerTask.TargetEntityId);
    if (station is null || site is null || site.State != ConstructionSiteStateKinds.Active)
    {
      ship.State = "idle";
      ship.TargetPosition = ship.Position;
      return "none";
    }

    if (!TryConsumeShipEnergy(ship, world.Balance.Energy.IdleDrain * deltaSeconds)
      || !TryConsumeStationEnergy(station, world.Balance.Energy.IdleDrain * deltaSeconds))
    {
      ship.State = "power-starved";
      ship.TargetPosition = ship.Position;
      return "none";
    }

    ship.TargetPosition = GetShipDockedPosition(ship, station);
    ship.Position = ship.TargetPosition;
    ship.ActionTimer = 0f;
    ship.State = "delivering-construction";

    foreach (var required in site.RequiredItems)
    {
      var delivered = GetInventoryAmount(site.DeliveredItems, required.Key);
      var remaining = MathF.Max(0f, required.Value - delivered);
      if (remaining <= 0.01f)
      {
        continue;
      }

      var moved = MathF.Min(remaining, world.Balance.TransferRate * deltaSeconds);
      moved = MathF.Min(moved, GetInventoryAmount(station.Inventory, required.Key));
      if (moved <= 0.01f)
      {
        continue;
      }

      RemoveInventory(station.Inventory, required.Key, moved);
      AddInventory(site.Inventory, required.Key, moved);
      AddInventory(site.DeliveredItems, required.Key, moved);
      return IsConstructionSiteReady(site) ? "construction-delivered" : "none";
    }

    return IsConstructionSiteReady(site) ? "construction-delivered" : "none";
  }

  private string UpdateBuildConstructionSite(ShipRuntime ship, SimulationWorld world, float deltaSeconds)
  {
    if (ship.DockedStationId is null)
    {
      ship.State = "idle";
      ship.TargetPosition = ship.Position;
      return "none";
    }

    var station = world.Stations.FirstOrDefault((candidate) => candidate.Id == ship.DockedStationId);
    var site = world.ConstructionSites.FirstOrDefault((candidate) => candidate.Id == ship.ControllerTask.TargetEntityId);
    if (station is null || site is null || site.BlueprintId is null || site.State != ConstructionSiteStateKinds.Active)
    {
      ship.State = "idle";
      ship.TargetPosition = ship.Position;
      return "none";
    }

    if (!IsConstructionSiteReady(site) || !world.ModuleRecipes.TryGetValue(site.BlueprintId, out var recipe))
    {
      ship.State = "waiting-materials";
      ship.TargetPosition = GetShipDockedPosition(ship, station);
      return "none";
    }

    if (!TryConsumeShipEnergy(ship, world.Balance.Energy.IdleDrain * deltaSeconds)
      || !TryConsumeStationEnergy(station, world.Balance.Energy.MoveDrain * deltaSeconds))
    {
      ship.State = "power-starved";
      ship.TargetPosition = ship.Position;
      return "none";
    }

    ship.TargetPosition = GetShipDockedPosition(ship, station);
    ship.Position = ship.TargetPosition;
    ship.ActionTimer = 0f;
    ship.State = "constructing";
    site.AssignedConstructorShipIds.Add(ship.Id);
    site.Progress += deltaSeconds;
    if (site.Progress < recipe.Duration)
    {
      return "none";
    }

    station.InstalledModules.Add(site.BlueprintId);
    PrepareNextConstructionSiteStep(world, station, site);
    return "site-constructed";
  }

  private string UpdateLoadWorkers(ShipRuntime ship, SimulationWorld world, float deltaSeconds)
  {
    if (ship.DockedStationId is null || !CanTransportWorkers(ship))
    {
      ship.State = "blocked";
      return "failed";
    }

    var station = world.Stations.FirstOrDefault((candidate) => candidate.Id == ship.DockedStationId);
    if (station is null || station.Population <= 0.01f)
    {
      ship.State = "idle";
      return "none";
    }

    var transfer = MathF.Min(station.Population, GetWorkerTransportCapacity(ship) - ship.WorkerPopulation);
    transfer = MathF.Min(transfer, 4f * deltaSeconds);
    if (transfer <= 0.01f)
    {
      return "none";
    }

    station.Population = MathF.Max(0f, station.Population - transfer);
    ship.WorkerPopulation += transfer;
    ship.State = "loading";
    return ship.WorkerPopulation >= GetWorkerTransportCapacity(ship) - 0.01f ? "workers-loaded" : "none";
  }

  private string UpdateUnloadWorkers(ShipRuntime ship, SimulationWorld world, float deltaSeconds)
  {
    if (ship.DockedStationId is null || !CanTransportWorkers(ship))
    {
      ship.State = "blocked";
      return "failed";
    }

    var station = world.Stations.FirstOrDefault((candidate) => candidate.Id == ship.DockedStationId);
    if (station is null || ship.WorkerPopulation <= 0.01f)
    {
      ship.State = "idle";
      return "none";
    }

    var transfer = MathF.Min(ship.WorkerPopulation, MathF.Max(0f, station.PopulationCapacity - station.Population));
    transfer = MathF.Min(transfer, 4f * deltaSeconds);
    if (transfer <= 0.01f)
    {
      return "none";
    }

    ship.WorkerPopulation = MathF.Max(0f, ship.WorkerPopulation - transfer);
    station.Population = MathF.Min(station.PopulationCapacity, station.Population + transfer);
    ship.State = "unloading";
    return ship.WorkerPopulation <= 0.01f ? "workers-unloaded" : "none";
  }

  private string UpdateUndock(ShipRuntime ship, SimulationWorld world, float deltaSeconds)
  {
    var task = ship.ControllerTask;
    if (ship.DockedStationId is null || task.TargetPosition is null)
    {
      ship.State = "idle";
      ship.TargetPosition = ship.Position;
      return "none";
    }

    var station = world.Stations.FirstOrDefault((candidate) => candidate.Id == ship.DockedStationId);
    var undockTarget = station is null
      ? task.TargetPosition.Value
      : GetUndockTargetPosition(station, ship.AssignedDockingPadIndex, world.Balance.UndockDistance);
    ship.TargetPosition = undockTarget;
    if (!TryConsumeShipEnergy(ship, world.Balance.Energy.MoveDrain * deltaSeconds))
    {
      ship.State = "power-starved";
      ship.TargetPosition = ship.Position;
      return "none";
    }

    if (station is not null && !TryConsumeStationEnergy(station, world.Balance.Energy.IdleDrain * deltaSeconds))
    {
      ship.State = "power-starved";
      ship.TargetPosition = ship.Position;
      return "none";
    }

    ship.State = "undocking";
    if (!AdvanceTimedAction(ship, deltaSeconds, world.Balance.UndockingDuration))
    {
      if (station is not null)
      {
        ship.Position = GetShipDockedPosition(ship, station);
      }
      return "none";
    }

    ship.Position = ship.Position.MoveToward(undockTarget, world.Balance.UndockDistance);
    if (ship.Position.DistanceTo(undockTarget) > task.Threshold)
    {
      return "none";
    }

    if (station is not null)
    {
      station.DockedShipIds.Remove(ship.Id);
      ReleaseDockingPad(station, ship.Id);
    }

    ship.DockedStationId = null;
    ship.AssignedDockingPadIndex = null;
    return "undocked";
  }

  private void AdvanceControlState(ShipRuntime ship, SimulationWorld world, string controllerEvent)
  {
    var commander = GetShipCommander(world, ship);
    if (ship.Order is not null && controllerEvent == "arrived")
    {
      ship.Order = null;
      ship.ControllerTask.Kind = "idle";
      if (commander is not null)
      {
        commander.ActiveOrder = null;
        commander.ActiveTask = new CommanderTaskRuntime
        {
          Kind = ShipTaskKinds.Idle,
          Status = "completed",
          TargetSystemId = ship.SystemId,
          Threshold = 0f,
        };
      }
      return;
    }

    if (ship.DefaultBehavior.Kind == "auto-mine")
    {
      switch (ship.DefaultBehavior.Phase, controllerEvent)
      {
        case ("travel-to-node", "arrived"):
          ship.DefaultBehavior.Phase = GetShipCargoAmount(ship) >= ship.Definition.CargoCapacity ? "travel-to-station" : "extract";
          break;
        case ("extract", "cargo-full"):
          ship.DefaultBehavior.Phase = "travel-to-station";
          break;
        case ("travel-to-station", "arrived"):
          ship.DefaultBehavior.Phase = "dock";
          break;
        case ("dock", "docked"):
          ship.DefaultBehavior.Phase = GetShipCargoAmount(ship) > 0.01f ? "unload" : "refuel";
          break;
        case ("unload", "unloaded"):
          ship.DefaultBehavior.Phase = "refuel";
          break;
        case ("refuel", "refueled"):
          ship.DefaultBehavior.Phase = "undock";
          break;
        case ("undock", "undocked"):
          ship.DefaultBehavior.Phase = "travel-to-node";
          ship.DefaultBehavior.NodeId = null;
          break;
      }
    }

    if (ship.DefaultBehavior.Kind == "auto-harvest-gas")
    {
      switch (ship.DefaultBehavior.Phase, controllerEvent)
      {
        case ("travel-to-node", "arrived"):
          ship.DefaultBehavior.Phase = GetShipCargoAmount(ship) >= ship.Definition.CargoCapacity ? "travel-to-station" : "extract";
          break;
        case ("extract", "cargo-full"):
          ship.DefaultBehavior.Phase = "travel-to-station";
          break;
        case ("travel-to-station", "arrived"):
          ship.DefaultBehavior.Phase = "dock";
          break;
        case ("dock", "docked"):
          ship.DefaultBehavior.Phase = GetShipCargoAmount(ship) > 0.01f ? "unload" : "refuel";
          break;
        case ("unload", "unloaded"):
          ship.DefaultBehavior.Phase = "refuel";
          break;
        case ("refuel", "refueled"):
          ship.DefaultBehavior.Phase = "undock";
          break;
        case ("undock", "undocked"):
          ship.DefaultBehavior.Phase = "travel-to-node";
          ship.DefaultBehavior.NodeId = null;
          break;
      }
    }

    if (ship.DefaultBehavior.Kind == "construct-station")
    {
      switch (ship.DefaultBehavior.Phase, controllerEvent)
      {
        case ("travel-to-station", "arrived"):
          ship.DefaultBehavior.Phase = "dock";
          break;
        case ("dock", "docked"):
          ship.DefaultBehavior.Phase = NeedsRefuel(ship) ? "refuel" : "deliver-to-site";
          break;
        case ("refuel", "refueled"):
          ship.DefaultBehavior.Phase = "deliver-to-site";
          break;
        case ("deliver-to-site", "construction-delivered"):
          ship.DefaultBehavior.Phase = "build-site";
          break;
        case ("construct-module", "module-constructed"):
        case ("build-site", "site-constructed"):
          ship.DefaultBehavior.Phase = "travel-to-station";
          ship.DefaultBehavior.ModuleId = null;
          break;
      }
    }

    if (ship.DefaultBehavior.Kind == "patrol" && controllerEvent == "arrived" && ship.DefaultBehavior.PatrolPoints.Count > 0)
    {
      ship.DefaultBehavior.PatrolIndex = (ship.DefaultBehavior.PatrolIndex + 1) % ship.DefaultBehavior.PatrolPoints.Count;
    }

    if (commander is not null)
    {
      SyncShipToCommander(ship, commander);
      if (commander.ActiveTask is not null)
      {
        commander.ActiveTask.Status = controllerEvent == "none" ? "active" : "completed";
      }
    }
  }

  private static void TrackHistory(ShipRuntime ship)
  {
    var signature = $"{ship.State}|{ship.DefaultBehavior.Kind}|{ship.ControllerTask.Kind}|{GetShipCargoAmount(ship):0.0}";
    if (signature == ship.LastSignature)
    {
      return;
    }

    ship.LastSignature = signature;
    ship.History.Add($"{DateTimeOffset.UtcNow:HH:mm:ss}  state={ship.State} behavior={ship.DefaultBehavior.Kind} task={ship.ControllerTask.Kind} cargo={GetShipCargoAmount(ship):0.#}");
    if (ship.History.Count > 18)
    {
      ship.History.RemoveAt(0);
    }
  }

  private static Vector3Dto ToDto(Vector3 value) => new(value.X, value.Y, value.Z);

  private sealed record DesiredMarketOrder(string Kind, string ItemId, float Amount, float Valuation, float? ReserveThreshold);
  private readonly record struct LagrangePointPlacement(string Designation, Vector3 Position);
}