logparser

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Text;

namespace Gorls.Parser
{
    public abstract class LogParser : ILogParser
    {
        EventLogEntryType[] _entryTypes = new EventLogEntryType[] { EventLogEntryType.Error, EventLogEntryType.Information, EventLogEntryType.Warning,
        EventLogEntryType.FailureAudit, EventLogEntryType.SuccessAudit };
        public LogTypeInfo LogInfo { get; set; }
        protected virtual string _parseMessageFromEntry(EventLogEntry entry)
        {
            return entry.Message;
        }
        public IEnumerable<LogData> ParseLogData()
        {
            if (LogInfo is null)
            {
                throw new EntryPointNotFoundException("SecLogParser.LogInfo is null!");
            }
            var entries = new EventLog(LogInfo.LogName).Entries;
            int firstIndex = 0;
            if(LogInfo.InstanceID != -1)
            {
                firstIndex = _parseLastLogId(entries);
            }
            for(var i = firstIndex; i < entries.Count; i++)
            {
                if(i >= entries.Count)
                {
                    break;
                }
                var msg = _parseMessageFromEntry(entries[i]);
                if (string.IsNullOrEmpty(msg))
                {
                    continue;
                }
                var eTypeID = _getEntryTypeID(entries[i].EntryType);
                if(eTypeID == -1)
                {
                    continue;
                }
                var ld = _initNewLogData(msg, entries[i], eTypeID);
                yield return ld;
            }
        }
        private int _getEntryTypeID(EventLogEntryType type)
        {
            for(var i = 0; i < _entryTypes.Length; i++)
            {
                if(type == _entryTypes[i])
                {
                    return i + 1;
                }
            }
            return -1;
        }
        private int _parseLastLogId(EventLogEntryCollection entries)
        {
            //for(var i = entries.Count - 1; i >=0; i--)
            //{
            //    if (_logDataIsLast(entries[i]))
            //    {
            //        return i;
            //    }
            //}
            for (var i = 0; i < entries.Count; i++)
            {
                if (_logDataIsLast(entries[i]))
                {
                    return i;
                }
            }
            return 0;
        }
        private bool _logDataIsLast(EventLogEntry el)
        {
            return el.InstanceId == LogInfo.InstanceID && _parseMessageFromEntry(el) == LogInfo.Message
                && timesAreEqual(el.TimeWritten, LogInfo.TimeWritten) && LogInfo.EntryType == el.EntryType.ToString();
        }
        private bool _logDataIsLast(LogData ld)
        {
            return ld.EntryTypeID == LogInfo.EntryTypeID && ld.LogTypeID == LogInfo.LogTypeID &&
                ld.Message == LogInfo.Message && timesAreEqual(ld.TimeWritten, LogInfo.TimeWritten);
        }
        private bool timesAreEqual(DateTime dt1, DateTime dt2)
        {
            return dt1.Year == dt2.Year && dt1.Month == dt2.Month && dt1.Day == dt2.Day &&
                dt1.Hour == dt2.Hour && dt1.Minute == dt2.Minute && dt1.Second == dt2.Second;
        }
        private LogData _initNewLogData(string message, EventLogEntry entry, int entryTypeID)
        {
            return new LogData
            {
                ID = entry.InstanceId,
                EntryTypeID = entryTypeID,
                LogTypeID = LogInfo.LogTypeID,
                Message = message,
                TimeWritten = entry.TimeWritten
            };
        }
        private string _getTimeString(DateTime dt)
        {
            return ((int)(DateTime.UtcNow - new DateTime(1970, 1, 1)).TotalSeconds).ToString();
            return DateTime.UtcNow.Subtract(dt).TotalSeconds.ToString();
            //return dt.ToString("dd.MM.yyyy HH:mm:ss");
        }
    }
}