using Godot;
using System.Collections.Generic;
using System.Linq;

using Rokojori.Extensions;
namespace Rokojori;

[Tool]
[GlobalClass]
public partial class FightManager:Node
{
  [Export]
  public int maxEngaged = 3;

  [Export]
  public int maxAttacking = 1;

  List<FightSlot> _slots = new List<FightSlot>();
  Dictionary<FightSlot,double> _lastAttackTime = new Dictionary<FightSlot,double>();

  ulong _cachedFrame = ulong.MaxValue;
  List<FightSlot> _cachedEngaged = new List<FightSlot>();
  List<FightSlot> _cachedAttackers = new List<FightSlot>();

  public static FightManager Get()
  {
    return Unique<FightManager>.Get();
  }

  public int registeredCount => _slots.Count;
  public int engagedCount => EngagedSlots().Count;
  public int attackingCount => AttackingSlots().Count;

  public void Register( FightSlot slot )
  {
    if ( slot == null || _slots.Contains( slot ) )
    {
      return;
    }

    _slots.Add( slot );
  }

  public void Unregister( FightSlot slot )
  {
    _slots.Remove( slot );
    _lastAttackTime.Remove( slot );
  }

  List<FightSlot> EngagedSlots()
  {
    RefreshFrameCache();
    return _cachedEngaged;
  }

  List<FightSlot> AttackingSlots()
  {
    RefreshFrameCache();
    return _cachedAttackers;
  }

  void RefreshFrameCache()
  {
    var frame = Engine.GetPhysicsFrames();

    if ( frame == _cachedFrame )
    {
      return;
    }

    _cachedFrame = frame;

    _cachedEngaged = _slots
      .OrderByDescending( s => s.priority )
      .Take( Mathf.Max( 0, maxEngaged ) )
      .ToList();

    var now = Time.GetTicksMsec() / 1000.0;

    _cachedAttackers = _cachedEngaged
      .OrderByDescending( s => s.priority )
      .ThenBy( s => _lastAttackTime.TryGetValue( s, out var t ) ? t : -1 )
      .Take( Mathf.Max( 0, maxAttacking ) )
      .ToList();

    _cachedAttackers.ForEach( s => _lastAttackTime[ s ] = now );
  }

  public bool IsEngaged( FightSlot slot )
  {
    return slot != null && EngagedSlots().Contains( slot );
  }

  public bool HasAttackPermission( FightSlot slot )
  {
    return slot != null && AttackingSlots().Contains( slot );
  }

  public bool IsAnyOtherAttacking( FightSlot self )
  {
    return AttackingSlots().Any( s => s != self );
  }
}