/***************************************************************************
 *                          StandardSaveStrategy.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 System.Threading.Tasks;
using Server.Guilds;

namespace Server
{
  public class StandardSaveStrategy : SaveStrategy
  {
    public enum SaveOption
    {
      Normal,
      Threaded
    }

    // TODO: Move to configuration
    public static SaveOption SaveType => SaveOption.Normal;

    private readonly Queue<Item> _decayQueue;

    public StandardSaveStrategy() => _decayQueue = new Queue<Item>();

    public override string Name => "Standard";

    protected bool PermitBackgroundWrite { get; set; }

    protected bool UseSequentialWriters => SaveType == SaveOption.Normal || !PermitBackgroundWrite;

    public override void Save(bool permitBackgroundWrite)
    {
      PermitBackgroundWrite = permitBackgroundWrite;

#pragma warning disable CA2008 // Do not create tasks without passing a TaskScheduler        *
      Task.WaitAll(Task.Factory.StartNew(SaveMobiles), Task.Factory.StartNew(SaveItems), Task.Factory.StartNew(SaveGuilds));
#pragma warning restore CA2008 // Do not create tasks without passing a TaskScheduler        *

      if (permitBackgroundWrite && UseSequentialWriters) // If we're permitted to write in the background, but we don't anyways, then notify.
        World.NotifyDiskWriteComplete();
    }

    protected void SaveMobiles()
    {
      var mobiles = World.Mobiles;

      IGenericWriter idx;
      IGenericWriter tdb;
      IGenericWriter bin;

      if (UseSequentialWriters)
      {
        idx = new BinaryFileWriter(World.MobileIndexPath, false);
        tdb = new BinaryFileWriter(World.MobileTypesPath, false);
        bin = new BinaryFileWriter(World.MobileDataPath, true);
      }
      else
      {
        idx = new AsyncWriter(World.MobileIndexPath, false);
        tdb = new AsyncWriter(World.MobileTypesPath, false);
        bin = new AsyncWriter(World.MobileDataPath, true);
      }
#pragma warning disable CA2008 // Do not create tasks without passing a TaskScheduler        *
      Task.Factory.StartNew(() =>
      {
        tdb.Write(World.m_MobileTypes.Count);

        for (var i = 0; i < World.m_MobileTypes.Count; ++i)
          tdb.Write(World.m_MobileTypes[i].FullName);

        tdb.Close();
      });
#pragma warning restore CA2008 // Do not create tasks without passing a TaskScheduler        *

      Parallel.ForEach(mobiles.Values, mobile => mobile.Serialize());
#pragma warning disable CA2008 // Do not create tasks without passing a TaskScheduler        *
      Task.Factory.StartNew(() =>
      {
        idx.Write(mobiles.Count);
        foreach (var m in mobiles.Values)
        {
          var start = bin.Position;

          idx.Write(m.TypeRef);
          idx.Write(m.Serial);
          idx.Write(start);
          idx.Write((int)m.SaveBuffer.Position);

          m.SaveBuffer.WriteTo(bin);
          m.FreeCache();
        }

        idx.Close();
        bin.Close();
      });
#pragma warning restore CA2008 // Do not create tasks without passing a TaskScheduler        *
    }

    protected void SaveItems()
    {
      var items = World.Items;

      IGenericWriter idx;
      IGenericWriter tdb;
      IGenericWriter bin;

      if (UseSequentialWriters)
      {
        idx = new BinaryFileWriter(World.ItemIndexPath, false);
        tdb = new BinaryFileWriter(World.ItemTypesPath, false);
        bin = new BinaryFileWriter(World.ItemDataPath, true);
      }
      else
      {
        idx = new AsyncWriter(World.ItemIndexPath, false);
        tdb = new AsyncWriter(World.ItemTypesPath, false);
        bin = new AsyncWriter(World.ItemDataPath, true);
      }

#pragma warning disable CA2008 // Do not create tasks without passing a TaskScheduler        *
      Task.Factory.StartNew(() =>
      {
        tdb.Write(World.m_ItemTypes.Count);

        for (var i = 0; i < World.m_ItemTypes.Count; ++i)
          tdb.Write(World.m_ItemTypes[i].FullName);

        tdb.Close();
      });
#pragma warning restore CA2008 // Do not create tasks without passing a TaskScheduler        *
      Parallel.ForEach(items.Values, item => item.Serialize());

      idx.Write(items.Count);

      var n = DateTime.UtcNow;

#pragma warning disable CA2008 // Do not create tasks without passing a TaskScheduler        *
      Task.Factory.StartNew(() =>
      {
        foreach (var item in items.Values)
        {
          if (item.Decays && item.Parent == null && item.Map != Map.Internal && item.LastMoved + item.DecayTime <= n)
          {
            Console.WriteLine($"Decay Item {item.Name ?? item.DefaultName} ({item.GetType().FullName})");
            _decayQueue.Enqueue(item);
          }

          var start = bin.Position;

          idx.Write(item.TypeRef);
          idx.Write(item.Serial);
          idx.Write(start);
          idx.Write((int)item.SaveBuffer.Position);

          item.SaveBuffer.WriteTo(bin);
          item.FreeCache();
        }

        idx.Close();
        bin.Close();
      });
#pragma warning restore CA2008 // Do not create tasks without passing a TaskScheduler        *
    }

    protected void SaveGuilds()
    {
      IGenericWriter idx;
      IGenericWriter bin;

      if (UseSequentialWriters)
      {
        idx = new BinaryFileWriter(World.GuildIndexPath, false);
        bin = new BinaryFileWriter(World.GuildDataPath, true);
      }
      else
      {
        idx = new AsyncWriter(World.GuildIndexPath, false);
        bin = new AsyncWriter(World.GuildDataPath, true);
      }

      Parallel.ForEach(BaseGuild.List.Values, guild => guild.Serialize());

      idx.Write(BaseGuild.List.Count);
#pragma warning disable CA2008 // Do not create tasks without passing a TaskScheduler        *
      Task.Factory.StartNew(() =>
      {
        foreach (var guild in BaseGuild.List.Values)
        {
          var start = bin.Position;

          idx.Write(0); // guilds have no typeid
          idx.Write(guild.Serial);
          idx.Write(start);
          idx.Write((int)guild.SaveBuffer.Position);

          guild.SaveBuffer.WriteTo(bin);
        }

        idx.Close();
        bin.Close();
      });
#pragma warning restore CA2008 // Do not create tasks without passing a TaskScheduler        *
    }

    public override void ProcessDecay()
    {
      while (_decayQueue.Count > 0)
      {
        var item = _decayQueue.Dequeue();

        if (item.OnDecay())
          item.Delete();
      }
    }
  }
}