using System;
using System.IO;
using System.Linq;
using System.Text;
using Vinno.FIS.Sonopost.Common;
using Vinno.IUS.Common.Log;

namespace Vinno.FIS.Sonopost.Helpers
{
    public class SonopostLogEngine : LogEngine
    {
        private const string InfoTag = "I ; ";
        private const string DebugTag = "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();

        private DateTime _date;
        private bool _disposed;

        public SonopostLogEngine()
        {
            var freeSpace = SystemHelper.GetHardDiskFreeSpace(AppDomain.CurrentDomain.BaseDirectory);
            if (freeSpace <= 10)//小于10个G
            {
                string[] logsType =
                {
                    "Logs",
                    "SmartLogs",
                    "TRTCClientLogs",
                    "TRTCLogs"
                };
                foreach (var type in logsType)
                {
                    var logDirectory = Path.Combine(SonopostConstants.DataFolder, type);
                    RemoveOldLogs(logDirectory);
                }
            }
        }

        ~SonopostLogEngine()
        {
            DoDispose();
        }

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

        private void InitializeLogger()
        {
            var today = DateTime.Today;

            var parentLogDirectory = Path.Combine(SonopostConstants.DataFolder, "Logs");

            var logDirectory = Path.Combine(parentLogDirectory, today.Year.ToString(), today.Month.ToString("D2"), today.Day.ToString("D2"));
            DirectoryHelper.CreateDirectory(logDirectory);
            var now = DateTime.Now;
            var logTag = $"{now:yyyyMMddHH}";
            var logFileName = $"Log_{logTag}.log";
            var logFilePath = Path.Combine(logDirectory, logFileName);
            if (!File.Exists(logFilePath))
            {
                _logWriter?.Dispose();
                var logFileStream = new FileStream(logFilePath, FileMode.Create, FileAccess.ReadWrite, FileShare.ReadWrite);
                _logWriter = new StreamWriter(logFileStream);
            }
            else
            {
                _logWriter?.Dispose();
                var logFileStream = new FileStream(logFilePath, FileMode.Open, FileAccess.ReadWrite, FileShare.ReadWrite);
                logFileStream.Position = logFileStream.Length;
                _logWriter = new StreamWriter(logFileStream);
            }
        }

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

        private 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(DebugTag);
            }
            else if (level == LogLevel.UserOperation)
            {
                sb.Append(UserOperationTag);
            }
            sb.Append(message);

            return sb.ToString();
        }

        private void RemoveOldLogs(string logDirectory)
        {
            if (Directory.Exists(logDirectory))
            {
                var folders = Directory.GetDirectories(logDirectory);
                foreach (var folder in folders)
                {
                    RemoveOldLogs(folder);
                }
                //删除超过7天的日志
                var files = Directory.GetFiles(logDirectory).Select(m => new FileInfo(m))
                   .Where(t => t.Exists && DateTime.Now - t.CreationTime >= TimeSpan.FromDays(7));
                foreach (var file in files)
                {
                    file.Delete();
                }
                if (Directory.GetFiles(logDirectory).Count() == 0 && Directory.GetDirectories(logDirectory).Count() == 0)
                {
                    Directory.Delete(logDirectory);
                }
            }
        }

        private void DoDispose()
        {
            if (!_disposed)
            {
                _logWriter?.Dispose();
                _disposed = true;
            }
        }

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