/**
  * Converts HF broadcast station data file HF_BCD.txt to required data files
  * @author Robert J Morton YE572246C
  * @version 22 November 2001 */

// This program uses the Java 1.1.8 API.

import java.io.*;

class hfbdp {
  public static void main(String args[]) throws IOException {

    BufferedReader r = new BufferedReader(
      new InputStreamReader(new FileInputStream("hfbsn.txt"))
    );
    Writer stations = new FileWriter("stations.txt");

    // create frequencies file for first station
    Writer frequencies  = new FileWriter("freqs000.txt");

    // create duplicates file
    Writer dups  = new FileWriter("duplicates.txt");

    String old_frequency = "";  // for capturing duplicates
    String old_station = "";    // for capturing duplicates

    String STATION = "";  // name of station currently being dealt with
    int sn = 0;           //  number of station within the list
    String s;             //to hold the current input line

    while((s = r.readLine()) != null) {  // read in the next line of text

      // find position of tab that separates freq from station name
      int x = s.indexOf('\t');

      String frequency = (s.substring(0, x));  // get the new frequency

      // get the new name and strip possible rogue spaces from it
      String station = (s.substring(x + 1, s.length())).trim();

      // If a duplicate entry is found, write it to the duplicates file.
      if(frequency.equals(old_frequency) && station.equals(old_station))
        dups.write(frequency + '\t' + station + "\n");
      old_frequency = frequency;
      old_station = station;

      /* If we are still dealing with the same station,
      write the next frequency for this station. */

      if(STATION.compareTo(station) == 0) {
        frequencies.write(frequency + "\n");

      } else {  // else it is a new station, so

        /* Make this station's name the current station
        name and write it to the stations file. */

        STATION = station;
        stations.write(station + "\n");

        /* If there are no stations within the list,
        close the station's frequencies file. */

        if(sn > 0)
          frequencies.close();

        String SN = "" + sn;  // form string version of station number

        /* If there are less than 10 stations in the list, pad the
        number of stations with two leading zeros; else if there are
        less than a hundred, pad it out with just one leading zero. */

        if(sn < 10)
          SN = "00" + SN;
        else if(sn < 100)
          SN = "0" + SN;

        // create a new frequencies file for this station
        frequencies = new FileWriter("freqs" + SN + ".txt");

        /* Write the first frequency for this station and increment the
        station number ready for the next pass. */

        frequencies.write(frequency + "\n"); sn++;
      }
    }
    dups.close(); stations.close(); frequencies.close(); r.close();
  }
}