using System;
using System.Collections.Generic;
using System.Text;
using System.Globalization;
using System.IO;

namespace DaoCommon
{
    public enum LogfileType
    {
        LogTransactions,
        LogEvents,
        LogDiscarded
    }



    public class Logfile : IDisposable
    {
        // Flag: Has Dispose already been called? 
        bool disposed = false; //IDisposable

        private LogfileType type;
        private string name;
        private String logDirectory;
        private LinkedList<string> logEntries = new LinkedList<string>();

        StreamWriter realLogFile = null;

        public Logfile(LogfileType type, string logname, string logDirectory)
        {
            this.type = type;
            this.logDirectory = logDirectory;
            this.name = logname;
        }

        public static string getNowString()
        {
            DateTime now = DateTime.Now;

            return now.ToString("s");
        }


        public string getLogFilename()
        {
            return getLogFilename(type, logDirectory, name);
        }

        public static string getLogFilename(LogfileType type, string logDirectory, string name)
        {

            DateTime now = DateTime.Now;
            string filename = logDirectory + "\\";

            //Find uge nr
            DateTimeFormatInfo dfi = DateTimeFormatInfo.CurrentInfo;
            Calendar myCal = CultureInfo.InvariantCulture.Calendar;//System.Globalization
            int week = myCal.GetWeekOfYear(now, dfi.CalendarWeekRule, dfi.FirstDayOfWeek);

            switch (type)
            {
                case LogfileType.LogEvents:
                    filename += "eventlog_";
                    break;

                case LogfileType.LogTransactions:
                    filename += "transactionlog_";
                    break;

                case LogfileType.LogDiscarded:
                    filename += "discardedlog_";
                    break;
            }


            filename += name + "_" + now.Year.ToString("D4") + "_W" + week.ToString("D2") + ".log";

            return filename;
        }

        private void checkAndOpenfile()
        {
            if (realLogFile != null)
                return;

            string filename = getLogFilename();

            realLogFile = new StreamWriter(filename, true);
        }

        public void writeLogEntry(string msg) 
        {
            checkAndOpenfile();

            realLogFile.WriteLine(getNowString() + " " + msg);
            realLogFile.Flush();
        }


        public void addSingleLogEntry(string msg)
        {
            msg = Logfile.getNowString() + " " + msg;
            lock (logEntries)
            {
                logEntries.AddFirst(msg);

                if (logEntries.Count > 20)
                {
                    logEntries.RemoveLast();
                }
            }

            string filename = getLogFilename();
            using (StreamWriter eventlog = new StreamWriter(filename, true))
            {
                eventlog.WriteLine(msg);
            }

            Console.WriteLine(msg);
        }

        public string[] getLog()
        {
            lock (logEntries)
            {
                List<string> tmpEntries = new List<string>();
                foreach (string s in logEntries)
                {
                    tmpEntries.Add(s);
                }
                return tmpEntries.ToArray();
            }
        }

        public void Dispose()
        {
            if (disposed)
                return;

            try
            {
                if (realLogFile != null)
                {
                    realLogFile.Close();
                    realLogFile.Dispose();
                }
            }
            catch (Exception e)
            {
                Console.WriteLine("Error disposing logfile : ", e.Message);
            }


            // Free any unmanaged objects here. 
            //
            disposed = true;
        }



    }
}