?using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Collections;
using System.Collections.Specialized;
using System.Threading;
using System.Text;
/// <summary>
/// ChatEngine 的摘要說明
/// </summary>
namespace UChat.ChatEngine
{
    public class ChatEngine:IChatEngine
    {
        const string msg = "<li class=\"{0}\">{1}</li>\r\n";
        const string userlistfmt = "<li>{0}</li>\r\n";

        const string serverstyle = "servermsg";
        const string userstyle = "usermsg";
        const string actionstyle = "actionmsg";

        const string timeoutfmt = "User {0} timed out";
        const string textlimitfmt = "{0}, your message was {1} characters long.  The limit is {2} characters.";
        const string nickinusefmt = "{0} a user with this nick already exists";
        const string joinedfmt = "User {0} has joined";
        const string nickfmt = "{0} is now known as {1}";
        const string killfmt = "<strong>User {0} has been terminated!</strong>";
        const string clearfmt = "<strong>User {0} has cleared all chat log!</strong>";
        const string unknowcmdfmt = "<strong>User {0} : Unknow command</strong>";
        const string mefmt = "{0} {1}";
        const string txtfmt = "{0}: {1}";

        const long timerdelay = 300000;
        const int maxbuffer = 20;
        const int textlimit = 100;

        Timer timer;
        Hashtable users;
        StringCollection chat;
        StringCollection pings;

        object syncRoot = new object();
        public ChatEngine()
        {
            //
            // TODO: 在此處添加構造函數邏輯
            //
            users = new Hashtable();
            chat = new StringCollection();
            pings = new StringCollection();

            TimerCallback OnTimerTick = new TimerCallback(TimerTick);
            timer = new Timer(OnTimerTick, null, timerdelay, timerdelay);
        }
        private void TimerTick(object state)
        {
            lock (syncRoot) 
            {
                string[] current = new string[users.Keys.Count];
                users.Keys.CopyTo(current, 0);
                foreach (string guid in current)
                {
                    if (!pings.Contains(guid)) 
                    {
                        chat.Add(this.MakeServerMessage(string.Format(timeoutfmt, users[guid].ToString())));
                        users.Remove(guid);
                    }
                }
                pings.Clear();
            }
        }
        public string[] Users
        {
            get 
            {
                string[] nicks = new string[users.Count];
                users.Values.CopyTo(nicks, 0);
                return nicks;
            }
        }
        public string UserList
        {
            get
            {
                StringBuilder sb = new StringBuilder();
                string[] nicks = new string[users.Count];
                users.Values.CopyTo(nicks, 0);
                foreach (string user in nicks)
                {
                    sb.Append(String.Format(userlistfmt, user));
                }
                return sb.ToString();
            }
        }
        public string BufferText
        {
            get 
            {
                StringBuilder sb = new StringBuilder();
                foreach (string line in chat)
                {
                    sb.Append(line);
                }
                return sb.ToString();
            }
        }
        public bool GuidExists(string guid)
        {
            return users.ContainsKey(guid);
        }
        public bool UserExists(string user)
        {
            return users.ContainsValue(user);
        }
        public void Ping(string guid)
        {
            lock (syncRoot) {
                pings.Add(guid);
            }
        }
        public void AddText(string guid, string text)
        {
            if (text.Trim().Length == 0) 
            {
                return;
            }
            if (text.Length > textlimit) 
            {
                chat.Add(MakeServerMessage(string.Format(textlimitfmt, users[guid].ToString(), text.Length, textlimit)));
                return;
            }
            while (chat.Count > maxbuffer)
            {
                chat.RemoveAt(0);
            }
            if (pings.Contains(guid)) { pings.Add(guid); }
            chat.Add(ParseText(users[guid].ToString(), text));
        }
        private string ParseText(string user, string text)
        {
            if (text.StartsWith("/me"))
            { 
                return MakeActionMessage(string.Format(mefmt,user,text.Replace("/me",string.Empty)));
                if(text.StartsWith("/admin"))
                {
                    string command =text.Replace("/admin",string.Empty).Trim();
                    string result = string.Empty;
                    switch(command)
                    {
                        case "clear":
                            chat.Clear();
                            result =MakeServerMessage(string.Format(clearfmt,user));
                            break;
                        default:
                            result = MakeServerMessage(string.Format(unknowcmdfmt, user));
                            break;
                    }
                    return result;
                }
                if (text.StartsWith("/nick"))
                {
                    string newnick = text.Replace("/nick", string.Empty).Trim();
                    if (UserExists(newnick))
                    {
                        return MakeServerMessage(string.Format(nickinusefmt, user));
                    }
                    string[] keys = new string[users.Count];
                    users.Keys.CopyTo(keys, 0);
                    foreach (string key in keys)
                    {
                        if (users[key].ToString() == user) 
                        {
                            users[key] = newnick;
                            return MakeServerMessage(string.Format(nickfmt, user, newnick));
                        }
                    }
                }
               
                
            }
            return MakeUserMessage(string.Format(txtfmt, user, text));
        }
        private string MakeUserMessage(string text)
        {
            return string.Format(msg, userstyle, text);
        }
        private string MakeActionMessage(string text)
        {
            return string.Format(msg, actionstyle, text);
        }
        private string MakeServerMessage(string text)
        {
            return string.Format(msg, serverstyle, text);
        }
        public void AddUser(string id, string user)
        {
            lock (syncRoot)
            {
                if (!UserExists(user))
                {
                    users.Add(id, user);
                    pings.Add(id);
                    chat.Add(this.MakeServerMessage(string.Format(joinedfmt, user)));
                }
            }
        }
        public void Remove(string user, string password)
        {
            if (password != "Add password here!")
            {
                return;
            }
            if (this.UserExists(user)) 
            {
                string[] keys = new string[users.Count];
                foreach (DictionaryEntry e in users)
                {
                    if (e.Value.ToString() == user)
                    {
                        chat.Add(this.MakeServerMessage(string.Format(killfmt, user)));
                        users.Remove(e.Key);
                        return;
                    }
                }
            }
            if (pings.Contains(user)) pings.Remove(user);
        }
    }
}