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# This is the Alien::Judy module, a way to ensure that users who don't
# natively have libJudy on their system can still get one. It provides
# libJudy.so and Judy.h at the path $Config{sitearch}/Alien/Judy.
package Alien::Judy;
# ABSTRACT: A wrapper for installing the Judy library

use strict;
use warnings;
use vars qw( $VERSION $DEBUG $HANDLE );
use Config ();
use Cwd ();
use File::Spec ();
use DynaLoader ();

# This module allows users to import its three public functions
# inc_dirs(), lib_dirs(), and dl_load_libjudy().
use Sub::Exporter -setup => {
    exports => [qw( inc_dirs lib_dirs dl_load_libjudy )]
};

# The provided functions inc_dirs() and lib_dirs() are currently
# identical. Initially, they weren't.
*lib_dirs = \&inc_dirs;

# TODO: add literate documentation
sub inc_dirs {
    # Find files from ., $sitearch and @INC.
    my @dirs =
        grep { defined() && length() }
            @Config::Config{qw(sitearchexp sitearch)},
            @INC,
            Cwd::getcwd();

    # But first try to find them in $_/Alien/Judy/
    unshift @dirs,
        map { File::Spec->catdir( $_, 'Alien', 'Judy' ) }
        @dirs;

    # Return the unique-ified list
    my %seen;
    return
        grep { ! $seen{$_}++ }
        @dirs;
}

# This module depends on libJudy from
# http://judy.sourceforge.net. Either I can find it as a
# system-installed library:
#
#   apt-get install libjudydebian1  # for libJudy.so
#   apt-get install libjudy-dev     # for Judy.h
#
# Or I can get it by the perl CPAN module Alien::Judy which builds and
# installs Judy.h and libJudy.so into $Config{sitearch}/Alien/Judy.
#
# CPAN testers however won't have actually installed libJudy so I'll
# need to find it in @INC as set by $ENV{PERL5LIB} with a typical
# value of:
#
#   $INC[...] = '/home/josh/.cpan/build/Alien-Judy-0.01/blib/arch'
#
# but the files Judy.h and libJudy.so are a couple levels deeper at:
#
#   $INC[...] = '/home/josh/.cpan/build/Alien-Judy-0.01/blib/arch/Alien/Judy'
#
sub _libjudy_candidates {
    # Get a list of possible libJudy.so files.
    #
    # When writing this module, I found it would occasionally not only
    # find libJudy.so but also blib/arch/Judy/Judy.so which is the
    # Perl XS module. That was when this -lJudy resolving code was
    # directly in the Judy cpan module though which has a lib/Judy.xs
    # file. It's plausible that it's entirely irrelevant now that this
    # is in Alien::Judy.
    #