package Text::Upmake::Bakefile0;

use Exporter qw(import);
our @EXPORT = qw(update_bakefile_0);

=head1 NAME

Text::Upmake::Bakefile0 - Update bakefile-0.x files list.

=head1 SYNOPSIS

This is used exclusively to update wxWidgets C<files.bkl> and is probably not
useful outside of wxWidgets project.

    use Text::Upmake::Bakefile0;
    Text::Upmake::upmake('bakefiles/files.bkl', \&update_bakefile_0, $vars);

=head1 SEE ALSO

Text::Upmake

=head1 AUTHOR

Vadim Zeitlin

=cut

# Update file with variable definitions in bakefile-0 format with the data
# from the hash ref containing all the file lists.
#
# Takes the (open) file handles of the files to read and to write and the file
# lists hash ref as arguments.
#
# Returns 1 if any changes were made.
#
# The caller must take care of actually renaming the second file to the first
# one.
sub update_bakefile_0
{
    my ($in, $out, $vars) = @_;

    # Variable whose contents is being currently replaced.
    my $var;

    # Hash with files defined for the specified variable as keys and 0 or 1
    # depending on whether we have seen them in the input file as values.
    my %files;

    # Set to 1 if we made any changes.
    my $changed = 0;
    while (<$in>) {
        chomp;

        if (/<set var="(\w+)" hints="files">/ && exists $vars->{$1}) {
            $var = $1;
            %files = map { $_ => 0 } @{$vars->{$var}};
        } elsif (defined $var) {
            local $_ = $_;
            s/<!-- .* -->//;
            s/^\s+//;
            s/\s+$//;
            if (m{</set>}) {
                # Check if we have any new files.
                #
                # TODO Insert them in alphabetical order.
                while (my ($file, $seen) = each(%files)) {
                    if (!$seen) {
                        # This file was wasn't present in the input, add it.
                        # TODO Use proper indentation.
                        print $out "    $file\n";

                        $changed = 1;
                    }
                }

                undef $var;
            } elsif ($_) {
                if (not exists $files{$_}) {
                    # This file was removed.
                    $changed = 1;
                    next;
                }

                if ($files{$_}) {
                    warn qq{Duplicate file "$_" in the definition of the } .
                         qq{variable "$var" at line $.\n}
                } else {
                    $files{$_} = 1;
                }
            }
        }

        print $out "$_\n";
    }

    $changed
}