#!/usr/bin/perl
# ONO Hiroki onohiroki@cup.com
# http://onohiroki.cycling.jp/comp-google-latitude
# Usage: $ ./latitude_kml2gpx.pl *.kml

use strict;
use warnings;
use Data::Dumper;
use Encode;
use utf8;
use open ":utf8";
binmode STDIN,  ":utf8";
binmode STDOUT, ":utf8";
binmode STDERR, ":utf8";

foreach my $datafile (@ARGV) {
    printf "input: %-40s", $datafile;
    my $filename_str = $datafile;
    $filename_str =~ s/\.kml$//gi;
    #$filename_str =~ s/[^A-Za-z]//gi;
    my $output_filename = $filename_str.".gpx";

    unless (open KMLFILE, "< $datafile") {
        die "Cannot open file:$!";
    }

    unless (open GPXFILE, "> $output_filename") {
        die "Cannot open file:$!";
    }

    print GPXFILE <<'EOS';
<gpx xmlns="http://www.topografix.com/GPX/1/1"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://www.topografix.com/GPX/1/1
 http://www.topografix.com/GPX/1/1/gpx.xsd">
 <trk>
EOS

    my $time = q{};
    my $date = q{};
    while (<KMLFILE>) {
        if (m#<when>(.*)</when>#) {
            $time = $1;
            if ($date eq q{}) {
                $date = $time;
                $date =~ s/T.*$//;
                print GPXFILE "  <name>$date</name>\n";
                print GPXFILE "  <desc>$date</desc>\n";
                print GPXFILE "  <trkseg>\n";
            }
            $time = convert_datetime($time);
        }
        if (m#<gx:coord>(\S+)\s+(\S+)\s+(\S+)</gx:coord>#) {
            print GPXFILE q{   <trkpt lat="}.$2.q{" lon="}.$1.q{">};
            print GPXFILE "\n    <ele>$3</ele>\n    <time>$time</time>\n   </trkpt>\n";
        }
    }
    close KMLFILE;
    print GPXFILE "  </trkseg>\n </trk>\n</gpx>\n";
    close GPXFILE;
    print " output: ", $output_filename;
    print "\n";
}

sub convert_datetime {
    use DateTime::Format::HTTP;
    my $str = shift;
    my $dt = DateTime::Format::HTTP->parse_datetime($str);
    $dt->set_time_zone('+0000');
    return $dt . "Z";
}