#!/usr/bin/perl -w
use strict;
use Gtk2 '-init';
use Glib qw/TRUE FALSE/;
use GPS::NMEA;
use threads;
use threads::shared;

my $notebook;
my $gps_entry;
my $gps_start:shared = 0;
my $die:shared = 0;
my($ns,$lat,$ew,$lon):shared;
my $gps_current;

###################################################################################################
#start threads
my $thread_gps = threads->new( \&gps);

###################################################################################################
#timeouts
my $timer_gps = Glib::Timeout->add(100, \&gps_position);

###################################################################################################

#create window
my $window = Gtk2::Window->new('toplevel');
$window->signal_connect(delete_event=> sub {$die = 1; $thread_gps->join; Gtk2->main_quit});
$window->set_title("GPS Test");
  
#create notebook
$notebook = Gtk2::Notebook->new;
$notebook->set_tab_pos('top');

my $gps_table = Gtk2::Table->new(3, 2, FALSE);

#GPS Group (for all users)
my $gps_instruction = Gtk2::Label->new();
$gps_instruction->set_markup( '<span size="small">Enter the location of the GPS device (i.e. "COM4" or "/dev/lao")</span>');
my $gps_label = Gtk2::Label->new( 'Location');
$gps_current = Gtk2::Label->new;
$gps_entry = Gtk2::Entry->new();
$gps_entry->set_text("COM4");
my $start_stop = Gtk2::Button->new("Start");
$gps_table->attach_defaults($gps_instruction, 0, 2, 0, 1);
$gps_table->attach_defaults($gps_label, 0, 1, 1, 2);
$gps_table->attach_defaults($gps_entry, 1, 2, 1, 2);
$gps_table->attach_defaults($start_stop, 0, 1, 2, 3);
$gps_table->attach_defaults($gps_current, 1, 2, 2, 3);
#start and stop GPS device
$start_stop->signal_connect('clicked' => sub {if ( $start_stop->get_label eq "Start") {$start_stop->set_label("Stop"); $gps_start = 1;  print "$gps_start\n";} else {$start_stop->set_label("Start"); $gps_start = 0; print "$gps_start\n";}});

$notebook->append_page($gps_table, "GPS");

#add widgets
$window->add($notebook);
 
$window->show_all;
  
Gtk2->main;

####################################################################################################
#GPS Thread
sub gps{
  while (1) {
    #If program ends stop the loop
    goto END if $die == 1;
    
    if ($gps_start == 1) {
      
      #start the GPS Device
      my $gps_device = GPS::NMEA->new(Port => 'COM4', Baud => 4800);
      
      print "$gps_device\n";
      
      #start the loop  
      for (;;) {
        #stops the warnings in the GPS device module
        local $^W = 0;
        
        ($ns,$lat,$ew,$lon) = $gps_device->get_position;
        print "$gps_device\n";
        goto END if $die == 1;
        last if $gps_start == 0;
        sleep 3;
      }
      print "$gps_device\n";
      #undef $gps_device;
    } else {sleep 4}
  }
  END:
}

####################################################################################################

#GPS position timeout
sub gps_position{
  #set the current GPS position
  $gps_current->set_label("$ns $lat, $ew $lon") if $gps_start == 1 and defined($ns);
  $gps_current->set_label("N/A") if $gps_start == 0;
  return 1;
}