using System;
using System.IO;
using System.Text;

namespace Flyinsono.Client.Test
{
    public class DefaultLogEngine : LogEngine
    {
        private const string InfoTag = "I ; ";
        private const string DebguTag = "D ; ";
        private const string WarnTag = "W ; ";
        private const string ErrorTag = "E ; ";
        private const string VerboseTag = "V ; ";
        private const string UserOperationTag = "U ; ";

        private StreamWriter _logWriter;

        private readonly object _mutex = new object();
        public static string DataFolder;
        private DateTime _date;
        private bool _disposed;
       
        public DefaultLogEngine()
        {            
        }

        ~DefaultLogEngine()
        {
            //Dispose the StreamWriter when dispose.
            DoDispose();
        }

        private void DoDispose()
        {
            if (!_disposed)
            {
                _disposed = true;
            }
        }

        protected void InitializeLogger()
        {
            var logDirectory = Path.Combine(DataFolder, "Logs");
            if (!Directory.Exists(logDirectory))
            {
                Directory.CreateDirectory(logDirectory);
            }
            var now = DateTime.Now;
            var logTag = $"{now:yyyyMMddHHmmss}_{now.Millisecond:d3}";
            var logFileName = $"Log_{logTag}.log";
            var logFilePath = Path.Combine(logDirectory, logFileName);
            if (!File.Exists(logFilePath))
            {
                _logWriter?.Close();
                var logFileStream = new FileStream(logFilePath,FileMode.Create,FileAccess.ReadWrite,FileShare.ReadWrite);
                _logWriter = new StreamWriter(logFileStream);
            }
            else
            {
                _logWriter?.Close();
                var logFileStream = new FileStream(logFilePath, FileMode.Open, FileAccess.ReadWrite, FileShare.ReadWrite);
                logFileStream.Position = logFileStream.Length;
                _logWriter = new StreamWriter(logFileStream);
            }
        }

        public override void Write(LogLevel level, string msg)
        {
            lock (_mutex)
            {
                if (DateTime.Today != _date)
                {
                    InitializeLogger();
                    _date = DateTime.Today;
                }
                try
                {
                    var message = RecombinateMessage(level, msg);
                    WriteMessage(message);
                }
                catch (Exception)
                {
                    // There is exception during writing log, so just ignore
                }
            }
        }

        protected void WriteMessage(string message)
        {
            _logWriter.WriteLine(message);
            _logWriter.Flush();
        }

        protected string RecombinateMessage(LogLevel level, string msg)
        {
            var now = DateTime.Now;
            StringBuilder sb = new StringBuilder();
            sb.Append(
                $"[{now:yyyyMMddHHmmss},{now.Millisecond:d3}]-");
            string message = msg;
            if (level == LogLevel.Error)
            {
                sb.Append(ErrorTag);
            }
            else if (level == LogLevel.Warn)
            {
                sb.Append(WarnTag);
            }
            else if (level == LogLevel.Info)
            {
                sb.Append(InfoTag);
            }
            else if (level == LogLevel.Verbose)
            {
                sb.Append(VerboseTag);
            }
            else if (level == LogLevel.Debug)
            {
                sb.Append(DebguTag);
            }
            else if (level == LogLevel.UserOperation)
            {
                sb.Append(UserOperationTag);
            }
            sb.Append(message);

            return sb.ToString();
        }
        public override void Dispose()
        {
            DoDispose();
            GC.SuppressFinalize(this);
        }
    }
}