package main;
use strict;
use warnings;
# ABSTRACT: tab completion for global variables

use mop;

use Package::Stash;

use Reply::Util qw($fq_ident_rx $fq_varname_rx);

=head1 SYNOPSIS

  ; .replyrc
  [ReadLine]
  [Autocomplete::Globals]

=head1 DESCRIPTION

This plugin registers a tab key handler to autocomplete global variables in
Perl code.

=cut

class Reply::Plugin::Autocomplete::Globals extends Reply::Plugin {
    method tab_handler ($line) {
        my ($maybe_var) = $line =~ /($fq_varname_rx)$/;
        return unless $maybe_var;
        $maybe_var =~ s/\s+//g;

        my ($sigil, $rest) = $maybe_var =~ /(.)(.*)/;

        my @parts = split '::', $rest, -1;
        return if grep { /:/ } @parts;
        return if @parts && $parts[0] =~ /^[0-9]/;

        my $var_prefix = pop @parts;
        $var_prefix = '' unless defined $var_prefix;

        my $stash_name = join('::', @parts);
        my $stash = eval {
            Package::Stash->new(@parts ? $stash_name : 'main')
        };
        return unless $stash;

        my @symbols = map { s/^(.)main::/$1/; $_ } _recursive_symbols($stash);

        my $prefix = $stash_name
            ? $stash_name . '::' . $var_prefix
            : $var_prefix;

        my @results;
        for my $global (@symbols) {
            my ($global_sigil, $global_name) = $global =~ /(.)(.*)/;
            next unless index($global_name, $prefix) == 0;

            # this is weird, not sure why % gets stripped but not $ or @
            if ($sigil eq $global_sigil) {
                push @results, $sigil eq '%' ? $global : $global_name;
            }
            elsif ($global_sigil eq '@' && $sigil eq '$') {
                push @results, "$global_name\[";
            }
            elsif ($global_sigil eq '%') {
                push @results, "$global_name\{";
            }
        }

        return @results;
    }
}

sub _recursive_symbols {
    my ($stash) = @_;

    my $stash_name = $stash->name;

    my @symbols;
    for my $name ($stash->list_all_symbols) {
        # main can have things in it like "_<reader Foo::bar (defined at ...)"
        # which aren't real variables - don't complete them, because we only
        # care about things that can be used as literal variable names. be sure
        # to not also block out punctuation variables.
        # XXX fix for unicode
        # XXX fix for variables like ${^GLOBAL_PHASE}
        next unless $name =~ /^$fq_ident_rx(?:::)?$/ || length($name) == 1;

        if ($name =~ s/::$//) {
            my $next = Package::Stash->new(join('::', $stash_name, $name));
            next if $next->namespace == $stash->namespace;
            push @symbols, _recursive_symbols($next);
        }
        else {
            push @symbols, "\$${stash_name}::$name"
                if $stash->has_symbol("\$$name");
            push @symbols, "\@${stash_name}::$name"
                if $stash->has_symbol("\@$name");
            push @symbols, "\%${stash_name}::$name"
                if $stash->has_symbol("\%$name");
            push @symbols, "\&${stash_name}::$name"
                if $stash->has_symbol("\&$name");
            push @symbols, "\*${stash_name}::$name"
                if $stash->has_symbol($name);
        }
    }

    return @symbols;
}

1;