#!/usr/bin/env perl

use strict;
use warnings;
use autodie;

use constant BASE_DIR => '/home/ken/tmp/pm_11143050';
use constant {
    LEN_BASE_DIR => length BASE_DIR,
    FS_DIR => BASE_DIR . '/fs',
};

use Cwd 'abs_path';
use Data::Dump;

my %fs_map;
walk_fs(FS_DIR, \%fs_map);
dd \%fs_map;

sub walk_fs {
    my ($path, $fs_map) = @_;

    opendir(my $dh, $path);

    while (readdir $dh) {
        next if /^\.{1,2}$/;
        my $entry = "$path/$_";
        my $fs_path = fs_path($entry);

        if (-f $entry) {
            $fs_map->{$fs_path} = [file => []];
        }
        elsif (-l $entry) {
            $fs_map->{$fs_path} = [link => [canon_path($entry)]];
        }
        elsif (-d $entry) {
            if (exists $fs_map->{fs_path($path)}) {
                push @{$fs_map->{fs_path($path)}[1]}, canon_path($entry);
            }

            $fs_map->{$fs_path} =  [dir => []];

            walk_fs($entry, $fs_map);
        }
        else {
            warn "IGNORED '$entry': not a plain file, link or directory.\n";
        }
    }

    closedir $dh;

    return;
}

sub fs_path {
    return substr $_[0], LEN_BASE_DIR;
}

sub canon_path {
    return substr abs_path($_[0]), LEN_BASE_DIR;
}