#!/usr/bin/perl -s
use strict;
use POSIX;

use Text::Ngram qw(ngram_counts);
use Text::ExtractWords qw(words_count words_list);
use Text::Affixes;

my $version = '0.03';

our $NR_SAMPLES = 50;

our ($v,$h,$d,$u,$verbose,$locale);

if ($locale) {
    if ($u && $locale !~ /utf/i) {
        verbose("setting locale: $locale.UTF-8");
        POSIX::setlocale( &POSIX::LC_CTYPE, "$locale.UTF-8" );
    } else {
        verbose("setting locale: $locale");
        POSIX::setlocale( &POSIX::LC_CTYPE, $locale );
    }
    use locale;
}


our $utf8 = undef;
$utf8 = 1 if $u;

show_help()        if $h;
show_version()     if $v;

unless (-d || @ARGV) {
    $d = 1;
}

if ($d) {
    my @languages = @ARGV || <*-*>;
    for (@languages) {
        /(.+)-(.+)/ ||
          die "Can't figure out the language tag and name out of '$_'\n";
        make_module($1, $2, <$_/*>);
    }
}
else {
    my $tag      = shift || die "You must provide a language tag.\n";
    my $language = shift || die "You must provide a language name.\n";
    @ARGV                || die "You must provide at least one file.\n";
    verbose("Creating module for $tag for $language language");
    make_module(lc($tag), lc($language), @ARGV);
}

###############
# subroutines #
###############

sub verbose {
    print STDERR $_[0], "\n" if $verbose;
}

###

sub show_help {
    die "Usage: make-lingua-identify-language tag language file1 file2
 or:   make-lingua-identify-language -d directory1 directory2
make-lingua-identify-language: creates Lingua::Identify language modules

Examples:
  make-lingua-identify-language en english file1
  make-lingua-identify-language -d en-english/ pt-portuguese/
  make-lingua-identify-language

Options:
  -d         directory mode
  -h         displays this messages and exit
  -v         show version and exit
  -verbose   verbose mode
  -u         unicode
"
}

###

sub show_version { 
    die "make-lingua-identify-language version $version\n";
}

###

sub make_module {
    my ($tag, $name, @files) = @_;

    verbose("Studying $name ($tag)");

    # read all files in its directory
    my $text;

    my $meta = {
                'language_name' => $name,
                'sets'          => [],
               };
    $tag =~ /^..$/  and $meta->{'two_letter_code'}   = $tag;
    $tag =~ /^...$/ and $meta->{'three_letter_code'} = $tag;

    for (@files) {
        if ($utf8) {
            open( STDINO, '<:utf8', $_ ) || die $!;
        } else {
            open( STDINO, $_ ) || die $!;
        }
        if ($_ eq 'META.yml') {
            verbose("\tfound META.yml");
            while (<STDINO>) { # META.yml is processed here
                if (/^(\w+):\s*(\w+)$/) {
                    $meta->{$1} = $2;
                    verbose("\tassigned $1 to $2");
                }
                elsif (/^(\w+):\s*$/) {
                    my $id = $1;
                    while (<STDINO>) {
                        last if /^\s*$/;
                        if (/^\s*(\w*)\s*$/) {
                            push @{$meta->{$id}}, $1;
                            verbose("\tpushed $1 into $id");
                        }
                    }
                }
            }
        }
        else {
            if ($locale) {
                $text .= join "\n", map { lc } <STDINO>;
            } else {
                $text .= join "\n", <STDINO>;
            }
        }
        close STDINO;
    }

    # write some headers
    if ($utf8) {
        open( STDOUTO, ">:utf8" , ( uc $tag ) . ".pm" ) || die;
    } else {
        open( STDOUTO, ">" . ( uc $tag ) . ".pm" ) || die;
    }
    my $sets = join ", ", map { "'$_'" } @{$meta->{'sets'}};
    verbose("\t$sets");
    print STDOUTO "use utf8;\n" if $utf8;
    print STDOUTO "use strict;\n",
      "\n\${Lingua::Identify::languages{'_versions'}{'$tag'}} = '$version';\n",
      "\n\${Lingua::Identify::languages{'_names'}{'$tag'}} = '$name';\n",
      "\n\${Lingua::Identify::languages{'_sets'}{'$tag'}} = '$sets';\n";

    # write POD

    my $module_name = uc $tag;
    my $podname = ucfirst $name;

    print STDOUTO pod_unindent("

    =encoding utf8

    =head1 NAME

    Lingua::Identify::$module_name - Meta-information on $podname

    =head1 SYNOPSIS

    Nothing here is meant for public consumption. This module is to be
    loaded by Lingua::Identify.

    =head1 DESCRIPTION

    Automatically generated. Do not change this module yourself unless
    you know what you're doing.

    =head1 SEE ALSO

    Lingua::Identify(3).

    =head1 AUTHOR

    Jose Castro, C<< <cog\@cpan.org> >>

    =head1 COPYRIGHT AND LICENSE

    Copyright (C) 2010-2013 by Alberto Simões

    This library is free software; you can redistribute it and/or modify
    it under the same terms as Perl itself, either Perl version 5.8.4 or,
    at your option, any later version of Perl 5 you may have available.

    =cut
");

    # write prefixes information
    verbose("\tstudying prefixes");

    my $prefixes = get_prefixes( { min => 1, max => 4 }, $text );

    for my $i ( 1 .. 4 ) {
        select STDOUTO;
        print "\n\${Lingua::Identify::languages{'prefixes$i'}{'$tag'}} = {\n";
        my $total;
        for ( values %{ $$prefixes{$i} } ) { $total += $_; }
        for (
             (
              sort { $$prefixes{$i}{$b} <=> $$prefixes{$i}{$a} }
              keys %{ $$prefixes{$i} }
             )[ 0 .. $NR_SAMPLES - 1 ]
            )
          {
              print "  '$_'\t=> ", $$prefixes{$i}{$_} / $total, ",\n";
          }
        print "};\n";
    }

    # write suffixes information
    verbose("\tstudying suffixes");

    my $suffixes = get_suffixes( { min => 1, max => 4 }, $text );
    for my $i ( 1 .. 4 ) {
        select STDOUTO;
        print "\n\${Lingua::Identify::languages{'suffixes$i'}{'$tag'}} = {\n";
        my $total;
        for ( values %{ $$suffixes{$i} } ) { $total += $_; }
        for (
             (
              sort { $$suffixes{$i}{$b} <=> $$suffixes{$i}{$a} }
              keys %{ $$suffixes{$i} }
             )[ 0 .. $NR_SAMPLES - 1 ]
            )
          {
              print "  '$_'\t=> ", $$suffixes{$i}{$_} / $total, ",\n";
          }
        print "};\n";
    }

    # write words information
    verbose("\tstudying words");

    my $hash_w;
    if ($utf8) {
        $hash_w = my_words_count($text);
    } else {
        my %hash;
        words_count(\%hash, $text);
        $hash_w = \%hash;
    }
    my $total;
    for ( values %$hash_w ) { $total += $_; }
    print "\n\${Lingua::Identify::languages{'smallwords'}{'$tag'}} = {\n";
    for (( sort { $hash_w->{$b} <=> $hash_w->{$a} }
           grep { !/(?:[_'",;:.«»0-9\(\)\[\]\{\}\/\\\!\?%]|^-|-$)/ } keys %$hash_w )
         [ 0 .. $NR_SAMPLES - 1 ] )
      {
          print "  '$_'\t=> ", $hash_w->{$_} / $total, ",\n";
      }
    print "};\n";

    # write ngrams information
    my $f = sub { ngram_counts( {spaces => 0}, $_[0], $_[1]) };
    get_ngrams($tag, 'ngrams', 2, 4, $f, $text );

    get_letters($tag, 'letters', $f, $text);

    # close the file
    close(STDOUT);

}

###############################

sub get_letters {
    my ($tag, $what, $function, $text) = @_;

    verbose("\tstudying $what");

    my $hash = &{$function}($text, 1);

    my $total;
    for ( values %$hash ) {
        $total += $_;
    }

    print "\n\${Lingua::Identify::languages{'$what'}{'$tag'}} = {\n";

    for (sort { $$hash{$b} <=> $$hash{$a} } keys %$hash ) {
        print "  '$_' => ", $$hash{$_} / $total, ",\n";
    }

    print "};\n";

}

###############################

sub get_ngrams {
    my ($tag, $what, $min, $max, $function, $text) = @_;

    for my $gram ( $min .. $max ) {

        verbose("\tstudying $what $gram");

        #my $hash_r = ngram_counts( $text, $gram );
        my $hash = &{$function}($text, $gram);

        my $total;
        for ( values %$hash ) {
            $total += $_;
        }

        print "\n\${Lingua::Identify::languages{'$what$gram'}{'$tag'}} = {\n";

        for ((sort { $$hash{$b} <=> $$hash{$a} } keys %$hash )[ 0 .. $NR_SAMPLES - 1 ]) {
            print "  '$_' => ", $$hash{$_} / $total, ",\n";
        }

        print "};\n";

    }

}

###

sub pod_unindent { ( local $_ = shift ) =~ s/^ +//mg; $_ }

sub my_words_count {
    my $text = shift;
    my $count;
    for my $word (split /[\n\s]+/, $text) {
        $count->{$word}++;
    }
    return $count;
}

__END__

=encoding UTF-8

=head1 NAME

make-lingua-identify-language - creates language modules for Lingua::Identify

=head1 SYNOPSIS

  make-lingua-identify-language Language-Tag Language-Name file1 [file2 ...]

or

  make-lingua-identify-language -d TAG1-LANGUAGE1/ [TAG2-LANGUAGE2/ ...]

or

  make-lingua-identify

=head1 DESCRIPTION

Creates language modules to be used by Lingua::Identify.

After creating the modules, you still have to install them.

Please note that this script is still at an early stage. Please do not even
look at the code...

Without parameters, make-lingua-identify-language assumes mode -d and goes
through all the directories in the current one. This is useful to be used in a
directory where you something like this:

  .
  |-- en-english
  |   `-- english.txt
  |-- fr-french
  |   `-- french1.txt
  |   `-- french2.txt
  `-- pt-portuguese
      `-- portuguese.txt

=head2 OPTIONS

=head2 -d

Directory mode. Each parameter passed should be a directory whose name
must be of the form tag-name (e.g., en-english/ ). Each of the
directories passed should contain text files that can be used to train
Lingua::Identify.

=head2 -D

Debug mode. Only for development.

=head2 -h

Display help and exit.

=head2 -v

Show version and exit.

=head2 -verbose

Verbose mode.

=head2 -locale=C<< <locale> >>

Set a specific locale. This way your text will be all lowercased before analysed.

=head1 META.yml

C<META.yml> files are not parsed as other files, they are ignored.

In directory mode (C<-d> switch), C<META.yml> files are checked for
info on languages codes and sets.

Here's a simple C<META.yml> for you to put in your directories:

  two_letter_code:   pt
  three_letter_code: por
  sets:
    spoken_in_portugal

With that, the language will be identified with the two letter code
"pt" or the three letter code "por"; it will also be in the set
":spoken_in_portugal".

=head1 CONTRIBUTING WITH NEW LANGUAGES

Please do not contribute with modules you made yourself. It's easier
to contribute with unprocessed text, because that allows for new
versions of Lingua::Identify not having to drop languages down in case
I can't contact you by that time.

Use I<make-lingua-identify-language> to create a new module for your
own personal use, if you must, but try to contribute with unprocessed
text rather than those modules.

=head1 SEE ALSO

Lingua::Identify(3), langident(1)

=head1 AUTHOR

Alberto Simões C<< <ambs@cpan.org> >>

José Alves de Castro C<< <cog@cpan.org> >>

=head1 COPYRIGHT AND LICENSE

Copyright 2004-2005 by Jose Alves de Castro

Copyright 2006-2013 by Alberto Simões

This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself. 

=cut