using System;
using System.Collections;
using System.Collections.Generic;
using Server.Commands;
using Server.Gumps;
using Server.Mobiles;
using Server.Targeting;

namespace Server.Engines.Help
{
  public class SpeechLog : IEnumerable<SpeechLogEntry>
  {
    // Are speech logs enabled?
    public static readonly bool Enabled = true;

    // How long should we maintain each speech entry?
    public static readonly TimeSpan EntryDuration = TimeSpan.FromMinutes(20.0);

    // What is the maximum number of entries a log can contain? (0 -> no limit)
    public static readonly int MaxLength = 0;

    private readonly Queue<SpeechLogEntry> m_Queue;

    public SpeechLog() => m_Queue = new Queue<SpeechLogEntry>();

    public int Count => m_Queue.Count;

    IEnumerator<SpeechLogEntry> IEnumerable<SpeechLogEntry>.GetEnumerator() => m_Queue.GetEnumerator();

    IEnumerator IEnumerable.GetEnumerator() => m_Queue.GetEnumerator();

    public static void Initialize()
    {
      CommandSystem.Register("SpeechLog", AccessLevel.Counselor, SpeechLog_OnCommand);
    }

    [Usage("SpeechLog")]
    [Description("Opens the speech log of a given target.")]
    private static void SpeechLog_OnCommand(CommandEventArgs e)
    {
      Mobile from = e.Mobile;

      from.SendMessage("Target a player to view his speech log.");
      e.Mobile.Target = new SpeechLogTarget();
    }

    public void Add(Mobile from, string speech)
    {
      Add(new SpeechLogEntry(from, speech));
    }

    public void Add(SpeechLogEntry entry)
    {
      if (MaxLength > 0 && m_Queue.Count >= MaxLength)
        m_Queue.Dequeue();

      Clean();

      m_Queue.Enqueue(entry);
    }

    public void Clean()
    {
      while (m_Queue.Count > 0)
      {
        SpeechLogEntry entry = m_Queue.Peek();

        if (DateTime.UtcNow - entry.Created > EntryDuration)
          m_Queue.Dequeue();
        else
          break;
      }
    }

    public void CopyTo(SpeechLogEntry[] array, int index)
    {
      m_Queue.CopyTo(array, index);
    }

    private class SpeechLogTarget : Target
    {
      public SpeechLogTarget() : base(-1, false, TargetFlags.None)
      {
      }

      protected override void OnTarget(Mobile from, object targeted)
      {
        if (!(targeted is PlayerMobile pm))
        {
          from.SendMessage("Speech logs aren't supported on that target.");
        }
        else if (from != targeted && from.AccessLevel <= pm.AccessLevel && from.AccessLevel != AccessLevel.Owner)
        {
          from.SendMessage("You don't have the required access level to view {0} speech log.",
            pm.Female ? "her" : "his");
        }
        else if (pm.SpeechLog == null)
        {
          from.SendMessage("{0} has no speech log.", pm.Female ? "She" : "He");
        }
        else
        {
          CommandLogging.WriteLine(from, "{0} {1} viewing speech log of {2}", from.AccessLevel,
            CommandLogging.Format(from), CommandLogging.Format(targeted));

          Gump gump = new SpeechLogGump(pm, pm.SpeechLog);
          from.SendGump(gump);
        }
      }
    }
  }

  public class SpeechLogEntry
  {
    public SpeechLogEntry(Mobile from, string speech)
    {
      From = from;
      Speech = speech;
      Created = DateTime.UtcNow;
    }

    public Mobile From { get; }

    public string Speech { get; }

    public DateTime Created { get; }
  }
}