/***************************************************************************
 *                                 Sector.cs
 *                            -------------------
 *   begin                : May 1, 2002
 *   copyright            : (C) The RunUO Software Team
 *   email                : info@runuo.com
 *
 *   $Id$
 *
 ***************************************************************************/

/***************************************************************************
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 ***************************************************************************/

using System;
using System.Collections.Generic;
using Server.Items;
using Server.Network;

namespace Server
{
  public class RegionRect : IComparable
  {
    private Rectangle3D m_Rect;

    public RegionRect(Region region, Rectangle3D rect)
    {
      Region = region;
      m_Rect = rect;
    }

    public Region Region{ get; }

    public Rectangle3D Rect => m_Rect;

    int IComparable.CompareTo(object obj)
    {
      if (obj == null)
        return 1;

      if (!(obj is RegionRect regRect))
        throw new ArgumentException("obj is not a RegionRect", nameof(obj));

      return ((IComparable)Region).CompareTo(regRect.Region);
    }

    public bool Contains(Point3D loc)
    {
      return m_Rect.Contains(loc);
    }
  }


  public class Sector
  {
    // TODO: Can we avoid this?
    private static List<Mobile> m_DefaultMobileList = new List<Mobile>();
    private static List<Item> m_DefaultItemList = new List<Item>();
    private static List<NetState> m_DefaultClientList = new List<NetState>();
    private static List<BaseMulti> m_DefaultMultiList = new List<BaseMulti>();
    private static List<RegionRect> m_DefaultRectList = new List<RegionRect>();
    private bool m_Active;
    private List<NetState> m_Clients;
    private List<Item> m_Items;
    private List<Mobile> m_Mobiles;
    private List<BaseMulti> m_Multis;
    private List<Mobile> m_Players;
    private List<RegionRect> m_RegionRects;

    public Sector(int x, int y, Map owner)
    {
      X = x;
      Y = y;
      Owner = owner;
      m_Active = false;
    }

    public List<RegionRect> RegionRects
    {
      get
      {
        if (m_RegionRects == null)
          return m_DefaultRectList;

        return m_RegionRects;
      }
    }

    public List<BaseMulti> Multis
    {
      get
      {
        if (m_Multis == null)
          return m_DefaultMultiList;

        return m_Multis;
      }
    }

    public List<Mobile> Mobiles
    {
      get
      {
        if (m_Mobiles == null)
          return m_DefaultMobileList;

        return m_Mobiles;
      }
    }

    public List<Item> Items
    {
      get
      {
        if (m_Items == null)
          return m_DefaultItemList;

        return m_Items;
      }
    }

    public List<NetState> Clients
    {
      get
      {
        if (m_Clients == null)
          return m_DefaultClientList;

        return m_Clients;
      }
    }

    public List<Mobile> Players
    {
      get
      {
        if (m_Players == null)
          return m_DefaultMobileList;

        return m_Players;
      }
    }

    public bool Active => m_Active && Owner != Map.Internal;

    public Map Owner{ get; }

    public int X{ get; }

    public int Y{ get; }

    private void Add<T>(ref List<T> list, T value)
    {
      if (list == null) list = new List<T>();

      list.Add(value);
    }

    private void Remove<T>(ref List<T> list, T value)
    {
      if (list != null)
      {
        list.Remove(value);

        if (list.Count == 0) list = null;
      }
    }

    private void Replace<T>(ref List<T> list, T oldValue, T newValue)
    {
      if (oldValue != null && newValue != null)
      {
        int index = list?.IndexOf(oldValue) ?? -1;

        if (index >= 0)
          list[index] = newValue;
        else
          Add(ref list, newValue);
      }
      else if (oldValue != null)
      {
        Remove(ref list, oldValue);
      }
      else if (newValue != null)
      {
        Add(ref list, newValue);
      }
    }

    public void OnClientChange(NetState oldState, NetState newState)
    {
      Replace(ref m_Clients, oldState, newState);
    }

    public void OnEnter(Item item)
    {
      Add(ref m_Items, item);
    }

    public void OnLeave(Item item)
    {
      Remove(ref m_Items, item);
    }

    public void OnEnter(Mobile mob)
    {
      Add(ref m_Mobiles, mob);

      if (mob.NetState != null) Add(ref m_Clients, mob.NetState);

      if (mob.Player)
      {
        if (m_Players == null) Owner.ActivateSectors(X, Y);

        Add(ref m_Players, mob);
      }
    }

    public void OnLeave(Mobile mob)
    {
      Remove(ref m_Mobiles, mob);

      if (mob.NetState != null) Remove(ref m_Clients, mob.NetState);

      if (mob.Player && m_Players != null)
      {
        Remove(ref m_Players, mob);

        if (m_Players == null) Owner.DeactivateSectors(X, Y);
      }
    }

    public void OnEnter(Region region, Rectangle3D rect)
    {
      Add(ref m_RegionRects, new RegionRect(region, rect));

      m_RegionRects.Sort();

      UpdateMobileRegions();
    }

    public void OnLeave(Region region)
    {
      if (m_RegionRects != null)
      {
        for (int i = m_RegionRects.Count - 1; i >= 0; i--)
        {
          RegionRect regRect = m_RegionRects[i];

          if (regRect.Region == region) m_RegionRects.RemoveAt(i);
        }

        if (m_RegionRects.Count == 0) m_RegionRects = null;
      }

      UpdateMobileRegions();
    }

    private void UpdateMobileRegions()
    {
      if (m_Mobiles != null)
      {
        List<Mobile> sandbox = new List<Mobile>(m_Mobiles);

        foreach (Mobile mob in sandbox) mob.UpdateRegion();
      }
    }

    public void OnMultiEnter(BaseMulti multi)
    {
      Add(ref m_Multis, multi);
    }

    public void OnMultiLeave(BaseMulti multi)
    {
      Remove(ref m_Multis, multi);
    }

    public void Activate()
    {
      if (!Active && Owner != Map.Internal)
      {
        if (m_Items != null)
          foreach (Item item in m_Items)
            item.OnSectorActivate();

        if (m_Mobiles != null)
          foreach (Mobile mob in m_Mobiles)
            mob.OnSectorActivate();

        m_Active = true;
      }
    }

    public void Deactivate()
    {
      if (Active)
      {
        if (m_Items != null)
          foreach (Item item in m_Items)
            item.OnSectorDeactivate();

        if (m_Mobiles != null)
          foreach (Mobile mob in m_Mobiles)
            mob.OnSectorDeactivate();

        m_Active = false;
      }
    }
  }
}