using System;
using System.ComponentModel;
using System.Diagnostics;

namespace RSS
{
	/// <summary>
	/// Generates an RSS feed for entries in the event log.
	/// </summary>
	public class EventLogRSS : RSSGenerator
	{
    /// <summary>
    /// Creates a new <see cref="EventLogRSS"/> instance.
    /// </summary>
		public EventLogRSS()
		{
      Title = "Event Log Feed";
      Description = "Feed for the computer's event log";
		}

    /// <summary>
    /// Populates the event log RSS feed.
    /// </summary>
    protected override void PopulateFeed()
    {
      if (log == null)
        throw new Exception("Log property must be set before populating the feed.");

      ClearItems();
      EventLog eventLog = new EventLog();
      eventLog.Log = log;
      foreach (EventLogEntry entry in eventLog.Entries)
      {
        if ((sourceFilter != null) && (sourceFilter.Length > 0))
        {
          if (entry.Source == sourceFilter)
            AddItem(entry);
        }
        else
          AddItem(entry);
      }
    }

    private void AddItem(EventLogEntry entry)
    {
      RSSItem item = AddItem();
      item.Description = entry.Message;
      item.Title = entry.EntryType.ToString() + " - " + entry.Message;
      if (item.Title.Length > 100)
        item.Title = item.Title.Substring(0, 100) + "...";
      item.Date = entry.TimeGenerated;
      item.Author = entry.Source;
    }

    #region properties

    private string sourceFilter;
    /// <summary>
    /// Gets or sets the source which will be used to filter on.
    /// </summary>
    [Description("The event source which will be used to filter on")]
    [Category(RSSCategory)]
    public string SourceFilter
    {
      get { return sourceFilter; }
      set { sourceFilter = value; }
    }

    private string log;
    /// <summary>
    /// Gets or sets the log to read (Application, System etc).
    /// </summary>
    [Description("The log to read (Application, System etc)")]
    [Category(RSSCategory)]
    public string Log
    {
      get { return log; }
      set { log = value; }
    }

    #endregion
	}
}