import java.io.BufferedReader;
import java.io.InputStreamReader;

import java.security.MessageDigest;

import java.net.URL;

public class ICSParser
{

   public static void parse
   (
      final String url,
      final Group group,
      final boolean lazy,
      final boolean uid_override
   )
   throws Exception
   {
      final BufferedReader reader;
      final StringBuilder sb;

      boolean should_record, has_id, ignore_line;
      String line;
      String class_name;
      String hash_seed;
      int length;
      sb = new StringBuilder();
      reader =
         new BufferedReader(new InputStreamReader((new URL(url)).openStream()));

      class_name = "unknown";
      should_record = false;
      ignore_line = false;

      hash_seed = "";
      has_id = false;

      while ((line = reader.readLine()) != null)
      {
         if (line.startsWith("END:VEVENT"))
         {
            if (!has_id)
            {
               sb.append("UID:noid_");
               sb.append(hash_seed.hashCode());
               sb.append("\r\n");
            }

            sb.append(line);
            sb.append("\r\n");

            should_record = false;

            group.add_ICS_fragment(sb.toString(), class_name, lazy);
            sb.setLength(0);
         }
         else if (line.startsWith("BEGIN:VEVENT"))
         {
            should_record = true;
            has_id = false;
            hash_seed = "";
         }
         else if (line.startsWith("DTSTART:"))
         {
            hash_seed += line;
         }
         else if (line.startsWith("SUMMARY:"))
         {
            class_name = line.substring(8, line.length());
            hash_seed += line;
         }
         else if (line.startsWith("UID"))
         {
            if (uid_override)
            {
               ignore_line = true;
            }
            else
            {
               has_id = true;
            }
         }

         if (line.matches("\\w+:.*") && should_record)
         {
            if (!ignore_line)
            {
               sb.append(line);
               sb.append("\r\n");
            }

            ignore_line = false;
         }
      }

      reader.close();
   }
}