using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using Tango.Logging;

namespace Tango.Logging
{
    public class ApplicationLogFileParser : ILogFileParser<LogItemBase>
    {
        public List<LogFile> GetLogFiles()
        {
            List<LogFile> logFiles = new List<LogFile>();

            FileLogger logger = LogManager.Default.RegisteredLoggers.FirstOrDefault(x => x.GetType() == typeof(FileLogger)) as FileLogger;
            HashSet<string> dateStrings = new HashSet<string>();
            foreach (var file in Directory.GetFiles(FileLogger.DefaultLogsFolder, "*.log").Where(x => (Path.GetFileName(x).StartsWith(logger.Tag) && x != logger.LogFile)))
            {
                try
                {
                    String dateString = Path.GetFileNameWithoutExtension(file).Replace($"{logger.Tag}-", "");
                    int indexPos = dateString.IndexOf(FileLogger.FILE_SET_EXTENSION);
                    int indexOfFile = 0;
                    if (indexPos > 0)
                    {
                        string fileNameIndex = dateString.Substring(indexPos + FileLogger.FILE_SET_EXTENSION.Length);
                        int.TryParse(fileNameIndex, out indexOfFile);
                        dateString = dateString.Substring(0, indexPos);
                    }
                    if (!dateStrings.Contains(dateString))
                    {
                        dateStrings.Add(dateString);
                        DateTime date = DateTime.ParseExact(dateString, "dd-MM-yyyy_HH-mm-ss", CultureInfo.InvariantCulture);
                        logFiles.Add(new LogFile() { DateTime = date, File = file, PartOfSet = indexOfFile > 0, });
                    }
                }
                catch (Exception ex)
                {
                    LogManager.Default.Log(ex, $"Could not load application log file {Path.GetFileName(file)}");
                }
            }

            return logFiles;
        }

        public List<LogItemBase> Parse(LogFile logFile)
        {
            List<LogItemBase> logItems = new List<LogItemBase>();
            List<LogFile> logFiles = new List<LogFile>();
            FileLogger logger = LogManager.Default.RegisteredLoggers.FirstOrDefault(x => x.GetType() == typeof(FileLogger)) as FileLogger;
            if (logFile.PartOfSet)
            {
                string fileName = Path.GetFileNameWithoutExtension(logFile.File);
                string extension = Path.GetExtension(logFile.File);
                int indexPos = fileName.IndexOf(FileLogger.FILE_SET_EXTENSION);
                if (indexPos > 0)
                {
                    fileName = fileName.Substring(0, indexPos);
                }
                string[] fileEntries = Directory.GetFiles(FileLogger.DefaultLogsFolder, $"{fileName}*{extension}").Where(x => Path.GetFileName(x).StartsWith(logger.Tag) && x != logger.LogFile).OrderBy(x => x).ToArray();
                foreach (var file in fileEntries)
                {
                    Parse(file, logFile.DateTime, ref logItems);
                }
            }
            else
            {
                Parse(logFile.File, logFile.DateTime, ref logItems);
            }

            return logItems;
        }

        public List<LogItemBase> Parse(String file, DateTime fileDate)
        {
            List<LogItemBase> logs = new List<LogItemBase>();
            Parse(file, fileDate, ref logs);
            return logs;
        }

        private void Parse(string file, DateTime datetime, ref List<LogItemBase> logItems)
        {
            if(File.Exists(file))
            {
                String text = File.ReadAllText(file);
                var logs = Regex.Split(text, @"(\[\d{2}:\d{2}:\d{2}.\d{2}\])");

                for (int i = 1; i < logs.Length; i += 2)
                {
                    try
                    {
                        DateTime date = DateTime.ParseExact(logs[i].Replace("[", "").Replace("]", ""), "HH:mm:ss.ff", CultureInfo.InvariantCulture);
                        String rest = logs[i + 1];

                        var matches = Regex.Matches(rest, @"(?<=\[)(.*?)(?=\])");

                        MessageLogItem item = new MessageLogItem();
                        item.TimeStamp = new DateTime(datetime.Year, datetime.Month, datetime.Day, date.Hour, date.Minute, date.Second, date.Millisecond);
                        item.Category = (LogCategory)Enum.Parse(typeof(LogCategory), matches[0].ToString());
                        item.CallerFile = matches[1].ToString();
                        item.CallerMethodName = matches[2].ToString();
                        item.CallerLineNumber = int.Parse(matches[3].ToString());

                        int messageStartIndex = matches[3].Index + matches[3].Length + 2;
                        item.Message = rest.Substring(messageStartIndex, rest.Length - messageStartIndex);
                        logItems.Add(item);
                    }
                    catch (Exception ex)
                    {
                        LogManager.Default.Log(ex, "Could not parse log line: " + logs[i]);
                    }
                }
            }
        }
    }
}