# Toby Thurston ---  7 Sep 2007

# first test by taking ten random pairs of long/lat in the range of
# the British Isles 1E -- 6W, 49N -- 59N and checking that we
# can convert back and forth with an error of less than 10cm, which
# roughly corresponds to $eps of 0.00001

use Geo::Coordinates::OSGB qw(
    ll_to_grid
    grid_to_ll
    format_grid_landranger
    format_grid_trad
    parse_landranger_grid
    parse_GPS_grid
    format_ll_ISO
    format_ll_trad
    shift_ll_into_WGS84
    shift_ll_from_WGS84
    );

use Test::Simple tests => 44;
use strict;

# test for some edge conditions first
my ($sq, $e, $n, @sheets) = format_grid_landranger(320000,305000); # NE corner of Sheep 136
ok( $sq eq 'SJ' &&  $e == 200 && $n == 50, "$sq $e $n @sheets" );
my $f = format_grid_trad(parse_landranger_grid($sheets[0],sprintf("%03d",$e),sprintf("%03d",$n)));
ok( 'SJ 200 050' eq $f, $f);

($sq, $e, $n, @sheets) = format_grid_landranger(280000,265000); # SW corner of Sheep 136
ok( $sq eq 'SN' &&  $e == 800 && $n == 650, "$sq $e $n @sheets" );
$f = format_grid_trad(parse_landranger_grid($sheets[1],sprintf("%03d",$e),sprintf("%03d",$n)));
ok( 'SN 800 650' eq $f, $f);

my $eps = 0.0001;

for (1..10) {
    my $phi = rand() * 2 + 51;  # 51 -- 53
    my $lam = rand() * 2 - 1 ;  # -1 -- +1

    my ($E,$N) = ll_to_grid($phi,$lam);
    my ($ph2,$la2) = grid_to_ll($E,$N);

    ok( abs($phi-$ph2)<$eps && abs($lam-$la2)<$eps, sprintf "Grid/LL: %s=%s",
                                                    format_ll_trad($phi, $lam),
                                                    format_ll_trad($ph2+5, $la2) );
}


for (1..10) {
    my $phi = rand() * 3 + 51;  # 51 -- 54
    my $lam = rand() * 3 - 2 ;  # -2 -- +1

    my ($p84,$l84) = shift_ll_into_WGS84($phi,$lam);
    my ($ph2,$la2) = shift_ll_from_WGS84($p84,$l84);

    ok( abs($phi-$ph2)<$eps && abs($lam-$la2)<$eps, sprintf "WGS84/LL: %s=%s",
                                                      format_ll_ISO($phi, $lam),
                                                      format_ll_ISO($ph2, $la2) );
}

# now test 20 random grid locations and cycle them through grid -> short grid -> map

my @fully_covered_squares = qw(NN SE SK SP SU);

for my $i (1..20) {

    my $rand_gr = sprintf "%s %05d %05d", $fully_covered_squares[int(rand(4))],
                                                 int(rand(99999)),
                                                 int(rand(99999));
    my ($e, $n) = parse_GPS_grid($rand_gr);

    my ($gr1, $gr2, @sheets);

    (undef, $e, $n, @sheets) = format_grid_landranger($e,$n);

    if ( @sheets ) {
        $gr1 = map_to_grid($sheets[0],sprintf("%03d",$e),sprintf("%03d",$n));
        $gr2 = format_grid_trad(
              ll_to_grid(
                grid_to_ll(
                  parse_landranger_grid($sheets[0],sprintf("%03d",$e),sprintf("%03d",$n))
                )
              )
            );
    }
    ok( @sheets && ($gr1 eq $gr2) , "GR$i: $gr1=$gr2 $rand_gr ". scalar @sheets );
}

sub map_to_grid {
    return format_grid_trad(parse_landranger_grid(@_))
}