#!/usr/bin/perl
#
# This file is part of GNU Stow.
#
# GNU Stow is free software: you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# GNU Stow is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see https://www.gnu.org/licenses/.

use strict;
use warnings;

require 5.006_001;

use File::Find;
use Getopt::Long;

my $DEFAULT_TARGET = $ENV{STOW_DIR} || '/usr/local/';

our $Wanted   = \&bad_links;
our %Package  = ();
our $Stow_dir = '';
our $Target   = $DEFAULT_TARGET;

# put the main loop into a block so that tests can load this as a module
if ( not caller() ) {
    if (@ARGV == 0) {
        usage();
    }
    process_options();
    #check_stow($Target, $Wanted);
    check_stow();
}

sub process_options {
    GetOptions(
	'b|badlinks' => sub { $Wanted = \&bad_links },
	'a|aliens'   => sub { $Wanted = \&aliens    },
	'l|list'     => sub { $Wanted = \&list      },
	't|target=s' => \$Target,
	) or usage();
    return;
}

sub usage {
    print <<"EOT";
USAGE: chkstow [options]

Options:
    -t DIR, --target=DIR  Set the target directory to DIR
                          (default is $DEFAULT_TARGET)
    -b, --badlinks        Report symlinks that point to non-existent files
    -a, --aliens          Report non-symlinks in the target directory
    -l, --list            List packages in the target directory

--badlinks is the default mode.
EOT
    exit(0);
}

sub check_stow {
    #my ($Target, $Wanted) = @_;

    my (%options) = (
        wanted     => $Wanted,
        preprocess => \&skip_dirs,
    );

    find(\%options, $Target);

    if ($Wanted == \&list) {
        delete $Package{''};
        delete $Package{'..'};

        if (keys %Package) {
            print map "$_\n", sort(keys %Package);
        }
    }
    return;
}

sub skip_dirs {
    # skip stow source and unstowed targets
    if (-e ".stow" || -e ".notstowed" ) {
        warn "skipping $File::Find::dir\n";
        return ();
    }
    else {
        return @_;
    }
}

# checking for files that do not link to anything
sub bad_links {
    -l && !-e && print "Bogus link: $File::Find::name\n";
}

# checking for files that are not owned by stow
sub aliens  {
    !-l && !-d && print "Unstowed file: $File::Find::name\n";
}

# just list the packages in the target directory
# FIXME: what if the stow dir is not called 'stow'?
sub list {
    if (-l) {
        $_ = readlink;
        s{\A(?:\.\./)+stow/}{}g;
        s{/.*}{}g;
        $Package{$_} = 1;
    }
}

1; # Hey, it's a module!

# Local variables:
# mode: perl
# cperl-indent-level: 4
# End:
# vim: ft=perl