# -*- perl -*-

use strict;
use Config;
use File::Spec::Functions;

my %seen;

sub print_modules_real {
my ($base, $dir, $word) = @_;

# return immediately if potential completion doesn't match current word
# a double comparison is used to avoid dealing with string lengths
# (the shorter being the pattern to be used as the regexp)
# word 'Fi', base 'File' -> match 'File' against 'Fi'
# word 'File::Sp', base 'File' -> match 'File::Sp' against 'File'
return if
$base &&
$word &&
$base !~ /^\Q$word/ &&
$word !~ /^\Q$base/;

chdir($dir) or return;

# print each file
foreach my $file (glob('*.{pm,pod}')) {
$file =~ s/\.(?:pm|pod)$//;
my $module = $base . $file;
next if $module !~ /^\Q$word/;
next if $seen{$module}++;
print $module . "\n";
}

# recurse in each subdirectory
foreach my $directory (grep { -d } glob('*')) {
my $subdir = $dir . '/' . $directory;
if ($directory =~ /^(?:[.\d]+|$Config{archname}|auto)$/) {
# exclude subdirectory name from base
print_modules_real(undef, $subdir, $word);
} else {
# add subdirectory name to base
print_modules_real($base . $directory . '::', $subdir, $word);
}
}
}

sub print_modules {
my ($word) = @_;

foreach my $directory (@INC) {
print_modules_real(undef, $directory, $word);
}
}

sub print_functions {
my ($word) = @_;

my $perlfunc;
for ( @INC, undef ) {
return if not defined;
$perlfunc = catfile $_, qw( pod perlfunc.pod );
last if -r $perlfunc;
}

open my $fh, '<', $perlfunc or return;

my $nest_level = -1;
while ( <$fh> ) {
next if 1 .. /^=head2 Alphabetical Listing of Perl Functions$/;
++$nest_level if /^=over/;
--$nest_level if /^=back/;
next if $nest_level;
next unless /^=item (-?\w+)/;
my $function = $1;
next if $function !~ /^\Q$word/;
next if $seen{$function}++;
print $function . "\n";
}

}

my $type = shift;
my $word = shift;

if ($type eq 'functions') {
print_functions($word);
} elsif ($type eq 'modules') {
print_modules($word);
}