package TrigCalc;

use warnings;
use strict;

# use Data::Dump qw(dd pp);  # for debug

use parent 'Exporter';

our $VERSION = '0.1.0';

our @EXPORT    = qw();  # default exports: (none for now)
our @EXPORT_OK =        # optional exports
    qw(reduce)
    ;

use constant SECS_PER_DEGREE => 3600;
use constant SECS_PER_MINUTE =>   60;

# exported subroutines #############################################

sub reduce {

    # reduce from rightmost end of argument list.
    return secs_2_dms(dms_2_secs((reverse @_)[ 0 .. 2 ]));

    }

# non-exported (utility) subroutines ###############################

sub dms_2_secs {

    my ($secs,  # seconds
        $mins,  # minutes
        $degs,  # degrees
        ) = @_;

    $secs ||= 0;  # init as zero if undefined (or false: redundant)
    $mins ||= 0;
    $degs ||= 0;

    return $degs * SECS_PER_DEGREE + $mins * SECS_PER_MINUTE + $secs;

    }

sub secs_2_dms {

    use integer;

    my ($secs,  # seconds
        ) = @_;

    $secs ||= 0;  # init as zero if undefined (or false: redundant)

    my $degs = $secs / SECS_PER_DEGREE;   $secs %= SECS_PER_DEGREE;
    my $mins = $secs / SECS_PER_MINUTE;   $secs %= SECS_PER_MINUTE;

    return $degs, $mins, $secs;

    }

1;