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

namespace POSV.Utils
{
    public class ExceptionUtils
    {
        private static ExceptionUtils _current = null;
        public static ExceptionUtils Current
        {
            get
            {
                if (_current == null)
                {
                    System.Threading.Interlocked.CompareExchange(ref _current , new ExceptionUtils() , null);
                }
                return _current;
            }
        }

        public void Handle(Exception e)
        {
            try
            {
                string logFile = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, @"logs\errors");
                if (!Directory.Exists(logFile))
                {
                    Directory.CreateDirectory(logFile);
                }
                string exceptionName = e.GetType().Name;
                string filePath = logFile + @"\" + DateTime.Now.ToString("yyyyMMdd") + ".log";
                if (!File.Exists(logFile))
                {
                    File.Create(filePath);
                }

                using (StreamWriter sw = new StreamWriter(filePath, true, Encoding.Default))
                {
                    //确保线程安全
                    TextWriter tw = TextWriter.Synchronized(sw);
                    tw.Write(GetExceptionInfo(e));
                    tw.Close();
                }
            }
            catch
            {
                
            }
        }
        
        public static string GetExceptionInfo(Exception e)
        {
            string exceptionName = e.GetType().Name;
            StringBuilder sb = new StringBuilder();
            sb.Append(Environment.NewLine);
            sb.Append("---------------------Header-----------------");
            sb.Append(Environment.NewLine);
            sb.Append("<" + exceptionName + ">\n");
            sb.Append(Environment.NewLine);
            sb.Append("<LogDateTime>" + DateTime.Now + "</LogDateTime>\n");
            sb.Append(Environment.NewLine);
            sb.Append("<Message>" + System.Net.WebUtility.HtmlEncode(e.Message) + "</Message>\n");
            sb.Append(Environment.NewLine);
            if (e.Source != null)
            {
                sb.Append("<Source>" + e.Source + "</Source>\n");
                sb.Append(Environment.NewLine);
            }
            if (e.StackTrace != null)
            {
                sb.Append("<StackTrace>" + e.StackTrace + "</StackTrace>\n");
                sb.Append(Environment.NewLine);
            }
            if (e.InnerException != null)
            {
                sb.Append("<InnerException>" + System.Net.WebUtility.HtmlEncode(e.InnerException.ToString()) + "</InnerException>\n");
                sb.Append(Environment.NewLine);
            }
            sb.Append("<TargetSite>" + e.TargetSite + "</TargetSite>\n");
            sb.Append(Environment.NewLine);
            sb.Append("</" + exceptionName + ">\n");
            sb.Append(Environment.NewLine);
            sb.Append("---------------------Footer-----------------");
            sb.Append(Environment.NewLine);

            return sb.ToString();
        }
    }
}