#!/usr/bin/env perl

# use LWP::Simple;

$ATA100_data_filename = "../raw_data/FAA/ATA-100/current.zip";

use DB_File;

main: {
        #tie %APT,'DB_File',"./apt", O_RDWR, 0644 || die;

	open(PSV, ">apt.psv") || die;
	#$pattern = &get_pattern('subscr~2/apt_rf.txt');
	#$pattern = &get_pattern('Subscriber File Formats/Apt_rf.txt');
	#$pattern = &get_pattern('File Formats/Subscriber File Formats/Apt_rf.txt');
	#$pattern = &get_pattern('subscrib/apt_rf.txt');
	#$pattern = &get_pattern('formats/apt_rf.txt');
	#$pattern = &get_pattern('Formats/Apt_rf.txt');
	$pattern = &get_pattern('Subscriber_File_Formats/Apt_rf.txt');

	print STDERR "pattern=$pattern\n";

	print STDERR "getting airport data...\n";
	#&get_airport_data('APT.txt');
	#&get_airport_data('apt.txt');
	#&get_airport_data('APT.TXT');
	#&get_airport_data('APT.txt');
	#&get_airport_data('APT.TXT');
	&get_airport_data('APT.txt');

	dbmclose(%APT);
}

sub get_pattern {
	local($path) = @_;
	
	my $end = 1;
	my $count = 0;
	my $pattern = '';

	open(DESC, "unzip -C -p '$ATA100_data_filename' '$path' |") || die;
	while (<DESC>) {
		if (/^([LR] .*)$/) {
			($just, $type, $length, $start, $element, $desc) =
				unpack('A2A3A5A7A8A60', $_);
	
			printf(STDERR "%d: %s\n", $count, $desc);
			$field_index{$desc} = $count++;
	
			if ($start != $end) {
				#print PSV "pattern=$pattern\n";
				print "pattern=$pattern\n";
				last;
			}
	
	
			$end = $start + $length;
	
			$pattern .= sprintf('A%d', $length);
		}
	}
	close(DESC);

	return($pattern);
}


sub get_airport_data {
	local($path) = @_;


	open(APT, "unzip -C -p '$ATA100_data_filename' '$path' |") || die;
	while (<APT>) {
		chop;

		$line = $_;
		#print "callback($line)\n";

		@fields = unpack($pattern, $line);

		next if ($fields[0] ne 'APT');
		#print STDERR "$fields[3]\n";

		$id = $fields[$field_index{'LOCATION IDENTIFIER'}];
		print PSV "$id|";

		$data_string = '';

		foreach $field (
			$field_index{'OFFICIAL FACILITY NAME'},
			$field_index{'ASSOCIATED CITY NAME'},
			$field_index{'ASSOCIATED STATE POST OFFICE CODE'},
			$field_index{'LANDING FACILITY TYPE'},
			$field_index{'FACILITY USE'},
		) {
			print PSV $fields[$field] . '|';

			$data_string .= $fields[$field] . '|';
		}

		print PSV &sec_to_deg($fields[24]) . '|';
		$data_string .= &sec_to_deg($fields[24]) . '|';
		print PSV &sec_to_deg($fields[26]);
		$data_string .= &sec_to_deg($fields[26]);
		print PSV "\n";

		$APT{$id} = $data_string;
	}
	close(APT);
}

sub sec_to_deg {
    local($sec) = @_;
    my $deg;

    if ($sec =~ /^([0-9\.]+)([NSEW])$/) {
        $deg = $1 / 3600;
        $deg *= -1 if ($2 eq 'S');
        $deg *= -1 if ($2 eq 'W');
    }

    return($deg);
}