package GPS;

use strict;
use warnings;
use POSIX ();
use IO::Socket::INET;

our $VERSION = 0.01;



sub new {
   my ($class, %arg) = @_;
   $arg{port} ||= 2947;
   $arg{host} ||= 'localhost';

   print "$class\n";
   my $m = $class =~ /Raw$/ ? 'Coro::Socket' : 'IO::Socket::INET';
   my $sock = new $m PeerHost => $arg{host}, PeerPort => $arg{port}

         or die 'GPSD ($arg{host}:$arg{port}): $!';
   print $sock "HELO\n";
   <$sock> =~ /GPSD/ or die 'no GPSD';
   if($class =~/Raw$/) {
       print $sock "R\n";
       <$sock> =~ /GPSD,R=1/ or die "can't enable raw-mode";
   }
   
   bless {
      fh => $sock,
      minpoll => $arg{minpoll} || 1,
      last    => 0,
      data    => {},
   }, $class;
}

sub poll {
   my $self = shift;

   print {$self->{fh}} "dpva\n";

   if (readline ($self->{fh}) =~ m%GPSD,D=(\d\d)/(\d\d)/(\d\d\d\d) (\d\d):(\d\d):(\d\d),P=([\-0-9.]+) ([\-0-9.]+),V=([0-9.]+),A=([\-0-9.]+)%) {
      local $ENV{TZ} = "+0000";
      $self->{data} = {
         time => (POSIX::mktime $6,$5,$4,$2,$1-1,$3-1900,0,0),
         lat  => $7,
         long => $8,
         v    => $9,
         alt  => $10,
      };
      $self->{last} = time;
   }
}

sub data {
   $_[0]->poll if time - $_[0]{last} >= $_[0]{minpoll};
   $_[0]{data};
}

package GPS::Raw;
our @ISA = qw(GPS);
use strict;
use warnings;
use POSIX qw(modf);
use Coro::Socket;
use Coro::Event;
use Coro;

sub PI { 3.14159265 } # not used :)

sub latlon($$) {
   my ($t1,$t2) = modf($_[0] / 100);
   $t2 = $t2 + $t1*100 / 60;
   $t2 *= -1 if $_[1] =~ /[SW]/i;
   $t2
}

our %cbs = ( 'GPGLL' => sub { my ($res, @a) = @_;
      			      $res->{Plain}{Latitude} = $a[0];
                              $res->{lat} = latlon $a[0], $a[1];
                              $res->{Plain}{NS} = $a[1];
                              $res->{Plain}{Longitude} = $a[2];
                              $res->{long} = latlon $a[2], $a[3];
                              $res->{Plain}{WE} = $a[3];
                              $res->{Plain}{UTC} = $a[4];
                             },
             'PGRMZ' => sub { my ($res, @a) = @_;
             		      $res->{Plain}{Altitude} = $a[0];
                              $res->{alt} = $a[0] / 3.2808399; # foot -> meters
                            },
             'GPRMC' => sub { my ($res, @a) = @_;
             		      $res->{Plain}{Speed} = $a[6];
                              $res->{v} = $a[6] * 1.852; # knoten :)
             		      $res->{Plain}{Course} = $a[7];
                              $res->{course} = $a[7];
                            },
	     'GPRMB' => sub { my ($res, @a) = @_;
                	      $res->{WP}{origin} = $a[2];
                	      $res->{WP}{destination} = $a[3];
                	      $res->{WP}{destination} = $a[4];
                	      $res->{WP}{desLat} = latlon $a[5], $a[6];
                	      $res->{WP}{desLong} = latlon $a[7], $a[8];
                	      $res->{WP}{distance} = $a[9]* 1.852; #seemeilen -> km
                	      $res->{WP}{bearing} = $a[10];
                	      $res->{WP}{speed} = $a[11] *1852; #knoten->km/h

                            },
           );


sub _chksum($) {
	my ($line,$cs) = (shift,0);
        $line =~ m/\$([^\*]+)\*([0-9A-F]{2})$/ or do {
          warn "illegal line \"$line\"";
          return 0;
        };
        my ($str, $pcs) = ($1, $2);
	map {$cs ^= $_} unpack ("C*", $str);
        return 1 if $cs == hex($pcs);
        warn "illegal checksum. packet=$pcs computed=$cs";
        return 0;
}

sub get_line($) {
   my $sock = $_[0]{fh};
cserr:
   my $l =  readline $sock;
   $l =~ s/[\015\012\0]*//g;
   _chksum($l) or goto cserr;
   warn "unknown line \"$l\"" unless $l =~ /^\$([^,]+),([^\*]+)\*[A-F0-9]{2}$/;
   my ($cmd, $arg) = ($1,$2);
   ($l, $cmd, $arg);
}

sub daemon($) {
   my $self = shift;
   async {
        my $self = shift;
        my $res = $self->{data};
        use Data::Dumper;
        $res->{lines} = 0;
   	while(1) {
      		my($line, $cmd, $arg) = $self->get_line;
                $res->{lines}++;
                $res->{Raw}{$cmd} = $arg;
      		&{$cbs{$cmd}}($res, split /,/, $arg) if exists $cbs{$cmd};
   	}
   } $self;
}

sub data {
   cede;
   $_[0]{data};
}

1;