#!/usr/bin/perl

# http://www.kh-gps.de/nmea-faq.htm

use strict;

while(<STDIN>)
{
  chomp;
  chomp;

  # $GPGSA,A,3,27,28,08,10,13,19,,,,,,,2.6,1.3,2.3*39
  if(/^\$GPGSA,([^,]*),([^,]*),(.*),([^,]*),([^,]*),([^,]*)$/){
#    if($1 eq "A"){ print "Automatic"; }
#    elsif($1 eq "M"){ print "Manual"; }
#    else { print "Unknown"; }
#    print " mode ";
#
#    if($2 eq "1") { print "no"; }
#    elsif($2 eq "2") { print "2D"; }
#    elsif($2 eq "3") { print "3D"; }
#    else { print "unknown"; }
#    print " lock on SVs $3 with PDOP = $4 HDOP = $5 VDOP = $6\n";
  }
  # TODO: this is skipping message three, as there aren't a full set of SVs in it
  elsif(/^\$GPGSV,([^,]*),([^,]*),([^,]*),([^,]*),([^,]*),([^,]*),([^,]*),([^,]*),([^,]*),([^,]*),([^,]*),([^,]*),([^,]*),([^,]*),([^,]*)(.*)$/){
#    print "Message $2 of $1: $3 SVs in view\n";
#    print "	$4 SV PRN $5 deg elevation $6 deg azimuth from true north $7 signal to noise ratio\n";
#    print "	$8 SV PRN $9 deg elevation $10 deg azimuth from true north $11 signal to noise ratio\n";
#    print "	$12 SV PRN $13 deg elevation $14 deg azimuth from true north $15 signal to noise ratio\n";
  }
  elsif(/^\$GPRMC,([0-9][0-9])([0-9][0-9])([0-9][0-9])(\.[0-9]*),([^,]*),([^,]*),([^,]*),([^,]*),([^,]*),([^,]*),([^,]*),([0-9][0-9])([0-9][0-9])([0-9][0-9]),([^,]*),([^,]*)(.*)$/){
    print "RMC $1:$2:$3$4 $12/$13/$14 UTC $6 $7 $8 $9 at $10 knots (".($10 * 1.85200)." kmh) heading $11 true\n";
  }
  elsif(/^\$GPGGA,([0-9][0-9])([0-9][0-9])([0-9][0-9])(\.[0-9]*),([^,]*),([^,]*),([^,]*),([^,]*),([^,]*),([^,]*),([^,]*),([^,]*),([^,]*)(.*)$/){
    print "GGA $1:$2:$3$4 UTC $5 $6 $7 $8 ";

    if($9 eq "0") { print "invalid"; }
    elsif($9 eq "1") { print "gps"; }
    elsif($9 eq "2") { print "differential gps"; }
    else { print "unknown"; }
    print " fix to $10 SVs with $11 horizontal dilution altitude $12 $13\n";
  } 
  elsif(/^\$GPGSV.*$/){
  }

  else{
    print "		SKIPPED: $_\n";
  }
}