using System;
using System.Configuration;
using System.IO;
using System.Threading;

namespace Plane.Logging
{
    public class LocalFileLogger : Logger
    {
        private string _logDirPath = Path.Combine(
            Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData),
            "Plane",
            ConfigurationManager.AppSettings["LogEntry"] ?? AppDomain.CurrentDomain.FriendlyName,
            "Logs"
        );

        private object _logLock = new object();

        public LocalFileLogger()
        {
        }

        public LocalFileLogger(ILogger loggerToDecorate) : base(loggerToDecorate)
        {
        }

        private string LogDirPath
        {
            get
            {
                if (!Directory.Exists(_logDirPath))
                {
                    Directory.CreateDirectory(_logDirPath);
                }
                return _logDirPath;
            }
        }

        private string LogFilePath
        {
            get
            {
                return Path.Combine(LogDirPath, DateTime.Today.ToString("yyyyMMdd") + ".log");
            }
        }

        public override string ReadLog()
        {
            string text = "";
            if (File.Exists(LogFilePath))
                text = File.ReadAllText(LogFilePath);
            return text;
        }

        protected override void LogCore(string message, Category category, Priority priority)
        {
            lock (_logLock)
            {
                // TODO: 林俊清，20150605，应改为不使用 AppendAllText，提高性能。
                for (int i = 0; i < 5; i++)
                {
                    try
                    {
                        File.AppendAllText(LogFilePath,
                            BuildStandardLogEntry(message, category, priority));
                        break;
                    }
                    catch (IOException)
                    {
                        Thread.Sleep(100);
                    }
                }
            }
        }
    }
}