using System;
using Server.Items;
using Server.Network;

namespace Server
{
  public class LightCycle
  {
    public const int DayLevel = 0;
    public const int NightLevel = 12;
    public const int DungeonLevel = 26;
    public const int JailLevel = 9;

    private static int m_LevelOverride = int.MinValue;

    public static int LevelOverride
    {
      get => m_LevelOverride;
      set
      {
        m_LevelOverride = value;

        for (int i = 0; i < TcpServer.Instances.Count; ++i)
        {
          NetState ns = TcpServer.Instances[i];
          Mobile m = ns.Mobile;

          m?.CheckLightLevels(false);
        }
      }
    }

    public static void Initialize()
    {
      new LightCycleTimer().Start();
      EventSink.Login += OnLogin;

      CommandSystem.Register("GlobalLight", AccessLevel.GameMaster, Light_OnCommand);
    }

    [Usage("GlobalLight <value>")]
    [Description("Sets the current global light level.")]
    private static void Light_OnCommand(CommandEventArgs e)
    {
      if (e.Length >= 1)
      {
        LevelOverride = e.GetInt32(0);
        e.Mobile.SendMessage("Global light level override has been changed to {0}.", m_LevelOverride);
      }
      else
      {
        LevelOverride = int.MinValue;
        e.Mobile.SendMessage("Global light level override has been cleared.");
      }
    }

    public static void OnLogin(Mobile m)
    {
      m.CheckLightLevels(true);
    }

    public static int ComputeLevelFor(Mobile from)
    {
      if (m_LevelOverride > int.MinValue)
        return m_LevelOverride;

      Clock.GetTime(from.Map, from.X, from.Y, out int hours, out int minutes);

      /* OSI times:
       *
       * Midnight ->  3:59 AM : Night
       *  4:00 AM -> 11:59 PM : Day
       *
       * RunUO times:
       *
       * 10:00 PM -> 11:59 PM : Scale to night
       * Midnight ->  3:59 AM : Night
       *  4:00 AM ->  5:59 AM : Scale to day
       *  6:00 AM ->  9:59 PM : Day
       */

      if (hours < 4)
        return NightLevel;

      if (hours < 6)
        return NightLevel + ((hours - 4) * 60 + minutes) * (DayLevel - NightLevel) / 120;

      if (hours < 22)
        return DayLevel;

      if (hours < 24)
        return DayLevel + ((hours - 22) * 60 + minutes) * (NightLevel - DayLevel) / 120;

      return NightLevel; // should never be
    }

    private class LightCycleTimer : Timer
    {
      public LightCycleTimer() : base(TimeSpan.FromSeconds(0), TimeSpan.FromSeconds(5.0)) => Priority = TimerPriority.FiveSeconds;

      protected override void OnTick()
      {
        for (int i = 0; i < TcpServer.Instances.Count; ++i)
        {
          NetState ns = TcpServer.Instances[i];
          Mobile m = ns.Mobile;

          m?.CheckLightLevels(false);
        }
      }
    }

    public class NightSightTimer : Timer
    {
      private Mobile m_Owner;

      public NightSightTimer(Mobile owner) : base(TimeSpan.FromMinutes(Utility.Random(15, 25)))
      {
        m_Owner = owner;
        Priority = TimerPriority.OneMinute;
      }

      protected override void OnTick()
      {
        m_Owner.EndAction<LightCycle>();
        m_Owner.LightLevel = 0;
        BuffInfo.RemoveBuff(m_Owner, BuffIcon.NightSight);
      }
    }
  }
}