#!/usr/bin/env perl

use strict;
use warnings;

use Pod::Usage;
use File::Find;
use File::Spec;
use Cwd qw(abs_path);
use Getopt::Long qw(:config no_ignore_case bundling);

our $VERSION = '0.01';

=head1 NAME

gen-stopwords - Generate a .stopwords file for Test::Spelling::Stopwords

=head1 VERSION

Version 0.01

=head1 SYNOPSIS

    gen-stopwords [OPTIONS]

    # Basic usage (scans current directory, writes .stopwords)
    gen-stopwords

    # Specify language and output file
    gen-stopwords --lang en_US --output t/.stopwords

    # Scan specific directories
    gen-stopwords --dir lib --dir bin --dir t

    # Preview without writing
    gen-stopwords --dry-run --verbose

    # Show this help
    gen-stopwords --help

=head1 DESCRIPTION

Scans Perl source files (F<.pm>, F<.pl>, F<.pod>, F<.t>) and uses B<aspell>
to identify words that are not in the standard dictionary.  Those words are
collected into a F<.stopwords> file that your spelling test (e.g.
C<Test::Spelling>) can use to suppress false positives.

The generator:

=over 4

=item * Strips POD formatting codes (C<E<gt>>, C<L<...>>, C<C<...>>, etc.)
before passing lines to aspell, preventing artefacts like C<Egt>.

=item * Uses C<--run-together> so compound identifiers such as C<ResultSet>
and C<PendingChange> are handled correctly.

=item * Optionally seeds the list from your personal aspell wordlist
(F<~/.aspell.en.pws>) so project-specific words already known to you are
included automatically.

=item * Skips build/vendor directories (F<.git>, F<blib>, F<local>, etc.)
to keep the output clean.

=back

=head1 OPTIONS

=over 4

=item B<-l>, B<--lang> I<LANG>

Aspell language code to use. Defaults to C<en_GB>.

=item B<-o>, B<--output> I<FILE>

Path of the stopwords file to write. Defaults to C<.stopwords> in the
current directory.

=item B<-p>, B<--pws> I<FILE>

Path to your personal aspell wordlist. Defaults to
F<~/.aspell.en.pws>.  Use C<--no-global> to skip this entirely.

=item B<-d>, B<--dir> I<DIR>

Directory to scan. May be specified multiple times. Defaults to C<.>
(current directory).

=item B<-m>, B<--min-len> I<N>

Minimum word length to include. Defaults to C<2>.

=item B<-v>, B<--verbose>

Print the name of every file processed and extra detail.

=item B<-q>, B<--quiet>

Suppress all non-error output.

=item B<-n>, B<--dry-run>

Show what would be written without actually creating or modifying the
output file.

=item B<--no-global>

Do not load words from the personal aspell wordlist.

=item B<-V>, B<--version>

Print the version and exit.

=item B<-h>, B<--help>

Print this help message and exit.

=back

=cut

#
#
# CLI Options

my %opt = (
    lang      => 'en_GB',
    output    => '.stopwords',
    pws       => File::Spec->catfile($ENV{HOME} // '.', '.aspell.en.pws'),
    dirs      => [],
    min_len   => 2,
    verbose   => 0,
    quiet     => 0,
    dry_run   => 0,
    no_global => 0,
);

GetOptions(
    'lang|l=s'    => \$opt{lang},
    'output|o=s'  => \$opt{output},
    'pws|p=s'     => \$opt{pws},
    'dir|d=s@'    => \$opt{dirs},
    'min-len|m=i' => \$opt{min_len},
    'verbose|v'   => \$opt{verbose},
    'quiet|q'     => \$opt{quiet},
    'dry-run|n'   => \$opt{dry_run},
    'no-global'   => \$opt{no_global},
    'help|h'      => sub { pod2usage(-exitval => 0, -verbose => 2) },
    'version|V'   => sub { print "gen-stopwords $VERSION\n"; exit 0 },
) or pod2usage(-exitval => 1, -verbose => 1);

# Default to current directory if no --dir given
push @{ $opt{dirs} }, '.' unless @{ $opt{dirs} };

# Directories/patterns to prune during File::Find traversal
my @PRUNE_DIRS = qw(
    .git .build .svn .hg
    blib _build local cover_db extlib
    node_modules vendor
);

my $PRUNE_RE = do {
    my $pat  = join '|', map { quotemeta } @PRUNE_DIRS;
    qr/^(?:$pat)$/;
};

my $SOURCE_RE = qr/\.(pm|pod|pl|t)$/;

#
#
# Helpers

sub info  { print @_, "\n" unless $opt{quiet} }
sub debug { print @_, "\n" if $opt{verbose} && !$opt{quiet} }
sub warn_ { warn  @_, "\n" }

sub check_aspell {
    my $out = `aspell --version 2>&1`;
    die "ERROR: aspell not found or not executable. Please install aspell.\n"
        unless $? == 0 && $out =~ /aspell/i;
}

sub aspell_list {
    my ($line, $lang) = @_;

    (my $escaped = $line) =~ s/'/'\\''/g;
    return `echo '$escaped' | aspell list -l $lang --run-together 2>/dev/null`;
}

#
#
# Load Pod::Wordlist — the shared Perl community vocabulary

sub load_pod_wordlist {
    my $known = shift;

    unless (eval 'require Pod::Wordlist; 1') {
        warn_ "WARNING: Pod::Wordlist not found (cpanm Pod::Wordlist). "
            . "Skipping — .stopwords may contain redundant common Perl terms.";
        return 0;
    }

    # Pod::Wordlist stores its words in %Pod::Wordlist::Wordlist
    my $wordlist = do { no strict 'refs'; \%{ 'Pod::Wordlist::Wordlist' } };

    my $count = 0;
    for my $word (keys %$wordlist) {
        $known->{ lc $word } = 1;
        $count++;
    }

    debug("  Loaded $count word(s) from Pod::Wordlist");
    return $count;
}

#
#
# Load global personal wordlist (.aspell.en.pws)

sub load_global_words {
    my ($path, $list) = @_;

    return unless !$opt{no_global} && -e $path;

    open my $fh, '<', $path
        or do { warn_ "WARNING: Cannot open $path: $!"; return };

    my @lines = <$fh>;
    close $fh;

    shift @lines;    # skip aspell header line

    my $count = 0;
    for (@lines) {
        next unless /\S/;
        s/^\s+|\s+$//g;
        $list->{ lc($_) }++;
        $count++;
    }

    debug("  Loaded $count word(s) from $path");
}

#
#
# Scan source files and collect unrecognised words via aspell

sub scan_project {
    my ($dirs, $lang, $stop_file, $known, $stopwords) = @_;

    my $stop_abs  = eval { abs_path($stop_file) } // $stop_file;
    my $processed = 0;
    my $skipped   = 0;
    my $filtered  = 0;

    find({
        wanted => sub {
            my $name = $_;

            if (-d $name && $name =~ $PRUNE_RE) {
                $File::Find::prune = 1;
                return;
            }

            return unless -f $name && $name =~ $SOURCE_RE;

            my $abs = eval { abs_path($name) } // $name;
            if ($abs eq $stop_abs) {
                $skipped++;
                return;
            }

            debug("  Processing: $File::Find::name");
            $processed++;

            open my $fh, '<', $name
                or do { warn_ "WARNING: Cannot open $File::Find::name: $!"; return };

            while (my $line = <$fh>) {
                # Strip POD formatting codes entirely — prevents 'Egt' artefacts
                $line =~ s/[A-Z]<[^>]+>//g;

                my $result = aspell_list($line, $lang);
                next unless $result;

                for my $word (split /\n/, $result) {
                    $word =~ s/^\s+|\s+$//g;
                    next unless length($word) >= $opt{min_len};

                    my $clean = lc $word;
                    $clean =~ s/'s$//;

                    # Skip if Pod::Wordlist or personal wordlist already covers it
                    if ($known->{$clean}) {
                        $filtered++;
                        debug("    Skipping '$clean' (covered by Pod::Wordlist or personal wordlist)");
                        next;
                    }

                    $stopwords->{$clean}++;
                }
            }

            close $fh;
        },
        no_chdir => 0,
    }, @$dirs);

    # Explicit return ensures we always hand back three defined integers.
    # find() itself returns undef, so we must never let it be the implicit
    # return value of this sub — that is what causes the "uninitialized"
    # warning at the call site when $filtered is assigned from it.
    return ($processed, $skipped, $filtered + 0);
}

#
#
# Write .stopwords

sub write_stopwords {
    my ($path, $lang, $list) = @_;

    if ($opt{dry_run}) {
        info("DRY RUN — would write " . scalar(keys %$list) . " term(s) to $path");
        if ($opt{verbose}) {
            print "  $_\n" for sort keys %$list;
        }
        return;
    }

    open my $fh, '>', $path
        or die "ERROR: Cannot write to $path: $!\n";

    print $fh "# Auto-generated stopwords for $lang\n";
    print $fh "# Generated by gen-stopwords v$VERSION on " . localtime() . "\n";
    print $fh "# Do not edit manually — re-run gen-stopwords to regenerate.\n";
    print $fh join("\n", sort keys %$list), "\n";

    close $fh;
}

#
#
# Main Program

check_aspell();

info("gen-stopwords v$VERSION");
info("Language : $opt{lang}");
info("Output   : $opt{output}");
info("Dirs     : " . join(', ', @{ $opt{dirs} }));

# %known     - words NOT to add (covered by Pod::Wordlist or personal wordlist)
# %stopwords - words to write (project-specific only)
my (%known, %stopwords);

unless ($opt{no_wordlist}) {
    info("Loading Pod::Wordlist...");
    my $n = load_pod_wordlist(\%known);
    info("  $n word(s) loaded — these will be filtered from output.") if $n;
}

load_global_words($opt{pws}, \%known);

info("Scanning source files...");
my ($processed, $skipped, $filtered) = scan_project(
    $opt{dirs}, $opt{lang}, $opt{output}, \%known, \%stopwords
);

write_stopwords($opt{output}, $opt{lang}, \%stopwords);

info(sprintf(
    "Done. Scanned %d file(s), skipped %d, filtered %d already-known term(s).",
    $processed, $skipped, $filtered,
));
info(sprintf(
    "%s %d project-specific term(s) to %s.",
    $opt{dry_run} ? 'Would write' : 'Wrote',
    scalar(keys %stopwords),
    $opt{output},
));

=head1 REQUIREMENTS

=over 4

=item * Perl 5.14+

=item * B<aspell> must be installed and on C<$PATH>.

=back

=head1 EXIT STATUS

Exits C<0> on success, C<1> on usage error, and dies with a descriptive
message on fatal errors (missing aspell, unwritable output, etc.).

=head1 AUTHOR

Mohammad Sajid Anwar, C<< <mohammad.anwar at yahoo.com> >>

=head1 REPOSITORY

L<https://github.com/manwar/Test-Spelling-Stopwords>

=head1 LICENSE AND COPYRIGHT

Copyright (C) 2026 Mohammad Sajid Anwar.

This program  is  free software; you can redistribute it and / or modify it under
the  terms  of the the Artistic License (2.0). You may obtain a  copy of the full
license at:
L<http://www.perlfoundation.org/artistic_license_2_0>
Any  use,  modification, and distribution of the Standard or Modified Versions is
governed by this Artistic License.By using, modifying or distributing the Package,
you accept this license. Do not use, modify, or distribute the Package, if you do
not accept this license.
If your Modified Version has been derived from a Modified Version made by someone
other than you,you are nevertheless required to ensure that your Modified Version
 complies with the requirements of this license.
This  license  does  not grant you the right to use any trademark,  service mark,
tradename, or logo of the Copyright Holder.
This license includes the non-exclusive, worldwide, free-of-charge patent license
to make,  have made, use,  offer to sell, sell, import and otherwise transfer the
Package with respect to any patent claims licensable by the Copyright Holder that
are  necessarily  infringed  by  the  Package. If you institute patent litigation
(including  a  cross-claim  or  counterclaim) against any party alleging that the
Package constitutes direct or contributory patent infringement,then this Artistic
License to you shall terminate on the date that such litigation is filed.
Disclaimer  of  Warranty:  THE  PACKAGE  IS  PROVIDED BY THE COPYRIGHT HOLDER AND
CONTRIBUTORS  "AS IS'  AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES. THE IMPLIED
WARRANTIES    OF   MERCHANTABILITY,   FITNESS   FOR   A   PARTICULAR  PURPOSE, OR
NON-INFRINGEMENT ARE DISCLAIMED TO THE EXTENT PERMITTED BY YOUR LOCAL LAW. UNLESS
REQUIRED BY LAW, NO COPYRIGHT HOLDER OR CONTRIBUTOR WILL BE LIABLE FOR ANY DIRECT,
INDIRECT, INCIDENTAL,  OR CONSEQUENTIAL DAMAGES ARISING IN ANY WAY OUT OF THE USE
OF THE PACKAGE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

=cut
