space-game/apps/backend/Ships/AI/ShipController.cs

namespace SpaceGame.Api.Ships.AI;

// ─── Planning State ────────────────────────────────────────────────────────────

public sealed class ShipPlanningState
{
  public string ShipKind { get; set; } = string.Empty;
  public bool HasMiningCapability { get; set; }
  public bool FactionWantsOre { get; set; }
  public bool FactionWantsExpansion { get; set; }
  public bool FactionWantsCombat { get; set; }
  public bool FactionNeedsShipyard { get; set; }
  public string? TargetEnemySystemId { get; set; }
  public string? TargetEnemyEntityId { get; set; }
  public string? TradeItemId { get; set; }
  public string? TradeSourceStationId { get; set; }
  public string? TradeDestinationStationId { get; set; }
  public string? CurrentObjective { get; set; }

  public ShipPlanningState Clone() => (ShipPlanningState)MemberwiseClone();
}

// ─── Goals ─────────────────────────────────────────────────────────────────────

// A ship should always have an assigned objective. The planner picks the best one.
public sealed class AssignObjectiveGoal : GoapGoal<ShipPlanningState>
{
  public override string Name => "assign-objective";

  public override bool IsSatisfied(ShipPlanningState state) => state.CurrentObjective is not null;

  public override float ComputePriority(ShipPlanningState state, SimulationWorld world, CommanderRuntime commander) =>
      100f;
}

// ─── Actions ───────────────────────────────────────────────────────────────────

public sealed class SetMiningObjectiveAction : GoapAction<ShipPlanningState>
{
  public override string Name => "set-mining-objective";
  public override float Cost => 1f;

  public override bool CheckPreconditions(ShipPlanningState state) =>
      state.HasMiningCapability && state.FactionWantsOre;

  public override ShipPlanningState ApplyEffects(ShipPlanningState state)
  {
    state.CurrentObjective = "auto-mine";
    return state;
  }

  public override void Execute(SimulationEngine engine, SimulationWorld world, CommanderRuntime commander)
  {
    var ship = world.Ships.FirstOrDefault(s => s.Id == commander.ControlledEntityId);
    if (ship is null || string.Equals(ship.DefaultBehavior.Kind, "auto-mine", StringComparison.Ordinal))
    {
      return;
    }

    ship.DefaultBehavior.Kind = "auto-mine";
    ship.DefaultBehavior.Phase = null;
    ship.DefaultBehavior.NodeId = null;
  }
}

public sealed class SetPatrolObjectiveAction : GoapAction<ShipPlanningState>
{
  public override string Name => "set-patrol-objective";
  public override float Cost => 2f;

  public override bool CheckPreconditions(ShipPlanningState state) =>
      string.Equals(state.ShipKind, "military", StringComparison.Ordinal);

  public override ShipPlanningState ApplyEffects(ShipPlanningState state)
  {
    state.CurrentObjective = "patrol";
    return state;
  }

  public override void Execute(SimulationEngine engine, SimulationWorld world, CommanderRuntime commander)
  {
    var ship = world.Ships.FirstOrDefault(s => s.Id == commander.ControlledEntityId);
    if (ship is null || string.Equals(ship.DefaultBehavior.Kind, "patrol", StringComparison.Ordinal))
    {
      return;
    }

    if (ship.DefaultBehavior.PatrolPoints.Count == 0)
    {
      var station = world.Stations.FirstOrDefault(s =>
          s.FactionId == ship.FactionId &&
          string.Equals(s.SystemId, ship.SystemId, StringComparison.Ordinal));

      if (station is not null)
      {
        var radius = station.Radius + 90f;
        ship.DefaultBehavior.PatrolPoints.AddRange(
        [
          new Vector3(station.Position.X + radius, station.Position.Y, station.Position.Z),
          new Vector3(station.Position.X, station.Position.Y, station.Position.Z + radius),
          new Vector3(station.Position.X - radius, station.Position.Y, station.Position.Z),
          new Vector3(station.Position.X, station.Position.Y, station.Position.Z - radius),
        ]);
      }
    }

    ship.DefaultBehavior.Kind = "patrol";
  }
}

public sealed class SetAttackObjectiveAction : GoapAction<ShipPlanningState>
{
  public override string Name => "set-attack-objective";
  public override float Cost => 1f;

  public override bool CheckPreconditions(ShipPlanningState state) =>
      string.Equals(state.ShipKind, "military", StringComparison.Ordinal)
      && state.FactionWantsCombat
      && state.TargetEnemyEntityId is not null;

  public override ShipPlanningState ApplyEffects(ShipPlanningState state)
  {
    state.CurrentObjective = "attack-target";
    return state;
  }

  public override void Execute(SimulationEngine engine, SimulationWorld world, CommanderRuntime commander)
  {
    var ship = world.Ships.FirstOrDefault(s => s.Id == commander.ControlledEntityId);
    if (ship is null)
    {
      return;
    }

    ship.DefaultBehavior.Kind = "attack-target";
    ship.DefaultBehavior.AreaSystemId = commander.ActiveBehavior?.AreaSystemId ?? ship.DefaultBehavior.AreaSystemId;
    ship.DefaultBehavior.TargetEntityId = commander.ActiveBehavior?.TargetEntityId ?? ship.DefaultBehavior.TargetEntityId;
    ship.DefaultBehavior.Phase = null;
  }
}

public sealed class SetConstructionObjectiveAction : GoapAction<ShipPlanningState>
{
  public override string Name => "set-construction-objective";
  public override float Cost => 1f;

  public override bool CheckPreconditions(ShipPlanningState state) =>
      string.Equals(state.ShipKind, "construction", StringComparison.Ordinal)
      && (state.FactionWantsExpansion || state.FactionNeedsShipyard);

  public override ShipPlanningState ApplyEffects(ShipPlanningState state)
  {
    state.CurrentObjective = "construct-station";
    return state;
  }

  public override void Execute(SimulationEngine engine, SimulationWorld world, CommanderRuntime commander)
  {
    var ship = world.Ships.FirstOrDefault(s => s.Id == commander.ControlledEntityId);
    if (ship is null || string.Equals(ship.DefaultBehavior.Kind, "construct-station", StringComparison.Ordinal))
    {
      return;
    }

    ship.DefaultBehavior.Kind = "construct-station";
    ship.DefaultBehavior.Phase = null;
  }
}

public sealed class SetTradeObjectiveAction : GoapAction<ShipPlanningState>
{
  public override string Name => "set-trade-objective";
  public override float Cost => 1f;

  public override bool CheckPreconditions(ShipPlanningState state) =>
      string.Equals(state.ShipKind, "transport", StringComparison.Ordinal)
      && state.TradeItemId is not null
      && state.TradeSourceStationId is not null
      && state.TradeDestinationStationId is not null;

  public override ShipPlanningState ApplyEffects(ShipPlanningState state)
  {
    state.CurrentObjective = "trade-haul";
    return state;
  }

  public override void Execute(SimulationEngine engine, SimulationWorld world, CommanderRuntime commander)
  {
    var ship = world.Ships.FirstOrDefault(s => s.Id == commander.ControlledEntityId);
    if (ship is null || commander.ActiveBehavior is null)
    {
      return;
    }

    ship.DefaultBehavior.Kind = "trade-haul";
    ship.DefaultBehavior.ItemId = commander.ActiveBehavior.ItemId;
    ship.DefaultBehavior.StationId = commander.ActiveBehavior.StationId;
    ship.DefaultBehavior.TargetEntityId = commander.ActiveBehavior.TargetEntityId;
    ship.DefaultBehavior.Phase ??= "travel-to-source";
  }
}

public sealed class SetIdleObjectiveAction : GoapAction<ShipPlanningState>
{
  public override string Name => "set-idle-objective";
  public override float Cost => 10f;

  public override bool CheckPreconditions(ShipPlanningState state) => true;

  public override ShipPlanningState ApplyEffects(ShipPlanningState state)
  {
    state.CurrentObjective = "idle";
    return state;
  }

  public override void Execute(SimulationEngine engine, SimulationWorld world, CommanderRuntime commander)
  {
    var ship = world.Ships.FirstOrDefault(s => s.Id == commander.ControlledEntityId);
    if (ship is null || string.Equals(ship.DefaultBehavior.Kind, "idle", StringComparison.Ordinal))
    {
      return;
    }

    ship.DefaultBehavior.Kind = "idle";
  }
}