#!/usr/bin/perl

# make track db  BTREE "trackdb"
# companion to mk-photo-index5.pl
# Andrew Daviel 1998-2006 advax@triumf.ca

# reads Garmin GPS track data saved as GPX XML
# and creates location database


$file = shift or die "need GPX filename" ;
$level = 0 ;
use XML::LibXML;
use DB_File ;
use Time::Local ;

sub compare { my ($k1,$k2) = @_ ; $k1 <=> $k2 ; }

$b = new DB_File::BTREEINFO ;
$DB_BTREE->{'compare'} = \&compare ;
$b->{'compare'} = \&compare ;

$trackh = tie %track, "DB_File", "trackdb", O_RDWR|O_CREAT, 0666, $b
               or die "Cannot open file trackdb: $!\n" ;

$brkt = shift ;

$parser = XML::LibXML->new();
$doc = $parser->parse_file($file) ;

@trkpt = $doc->getElementsByLocalName('trkpt') ;

foreach $trkpt (@trkpt) {
  undef(%value) ; undef($ndg) ; undef($time2) ;
  if ($trkpt->hasAttributes) {
    foreach $attribute ($trkpt->attributes) {
      $aname = $attribute->name ; $avalue = $attribute->value ;
      $value{$aname} = $avalue ;
    }
  }
  if ($trkpt->hasChildNodes) {
    foreach $child ($trkpt->childNodes) {
      $name = $child->nodeName ;
      unless ($name eq 'ele' or $name eq 'time') { next ; }
      $value = $child->textContent;
      $value{$name} = $value ;
    }
  }
  print "$value{'lat'} $value{'lon'} $value{'ele'} $value{'time'}\n" ;

  $ndg = $value{'lat'} ; $edg = $value{'lon'} ;

  if ($value{'time'} =~ /([\d]+)-([\d]+)-([\d]+)T([\d]+):([\d]+):([\d]+)Z/) {
    $year = $1 ; $mon = $2 ; $mon-- ; $year -= 1900 ;
    $time2 = timegm($6,$5,$4,$3,$mon,$year) ;
    $time3 = localtime($time2) ;
  } else {
    print "garbled time $value{'time'}\n" ;
  }

  if ($time2) {
    if ($time2 == $brkt) { &brk ; }
    print "$time $time2 $time3 $ndg,$edg\n" ;
    if ($ndg > 0 and $time2) { $track{$time2} = "$ndg,$edg" ; }
  }
}
if ($brkt) {
  print STDERR "$track{$brkt}\n" ;
}
untie (%track) or die ;
$trackh = tie %track, "DB_File", "trackdb", O_RDWR|O_CREAT, 0666, $DB_BTREE
               or die "Cannot open file trackdb: $!\n" ;
#foreach (keys %track) {
#  $time = localtime($_) ;
#  print "$_ $time $track{$_}\n" ;
#}

if ($brkt) {
  print STDERR "$track{$brkt}\n" ;
}
untie (%track) or die ;

sub brk { return ; }