#!/usr/bin/perl -w

# sbofixinfo - fix common errors in SBo .info files.
# companion piece to sbolint.

$VERSION="0.1";

=pod

=head1 NAME

sbofixinfo - fix common errors in SlackBuilds.org .info files

=head1 SYNOPSIS

B<sbofixinfo> I<file-or-dir> [I<file-or-dir> I<...>]

=head1 DESCRIPTION

B<sbofixinfo> attempts to fix common errors in SlackBuilds.org .info
files. Each argument must be an .info file or a directory containing
an .info file. With no arguments, the .info file in the current
directory is checked.

B<sbofixinfo> attempts to fix the following errors in SBo .info files:

=over 4

=item -

Out-of-order keys will be reordered to match the order in the template.

=item -

Extraneous keys will be removed.

=item -

Blank lines will be removed.

=item -

Extra whitespace will be removed. This doesn't include indentation for
the 2nd and further lines of a multi-line value.

=item -

Missing \ (backslash) continuation characters will be added.

=item -

Missing " (double-quote) characters around key values will be added.

=item -

Values quoted with single-quotes will be quoted with double-quotes.

=item -

Multi-valued keys (e.g. DOWNLOAD with two URLs) will be split up into
multiple lines, if they're not already. Any missing line-continuation
backslashes will be added. Continuation lines will be correctly
indented.

=item -

Any capitalized hex digits in MD5SUM or MD5SUM_x86_64 will be lowercased.

=item -

Lowercase key names (e.g. md5sum or download) will be uppercased.

=back

B<sbofixinfo> doesn't attempt to detect any other errors or dubious
constructs. Use B<sbolint> before and after running B<sbofixinfo> for
comprehensive checking.

The file is modified 'in-place', in the same way as the B<-i> option
to B<sed>(1).

B<sbofixinfo> keeps a backup of the original file with the
extension I<.bak> appended to the filename. If the backup file already
exists, it will be silently overwritten. After the new file is generated,
B<diff>(1) (with its B<-u> and B<--color> options) is run on the backup and modified
files, and the backup is deleted if the new file is identical. The diff
output also goes to stdout, so the user can see what changes were made.

=head1 EXIT STATUS

Will be 0 for success. If any errors reading or writing any of the .info
files occur, the exit status will be the error count.

=head1 BUGS

Misspelled key names (e.g. MD5USM or DOWNLAOD) will be discarded. Not
a true bug (it's by design), but it violates the principle of least
surprise a bit.

B<sbofixinfo> can't automatically fix every issue B<sbolint> reports.
In particular, missing or extra values (for valid keys) can't
automatically be fixed. This isn't really a bug, as B<sbofixinfo>
can't know what to do in these situations. In other words, B<sbofixinfo>
operates only at the syntactic level, and knows nothing of semantics.

=head1 AUTHOR

B. Watson (yalhcru at slackware.uk, or Urchlay on Libera IRC)

=head1 SEE ALSO

B<sbolint>(1), B<sbopkglint>(1)

=cut

($SELF = $0) =~ s,.*/,,;

@keyorder = qw{
	PRGNAM
	VERSION
	HOMEPAGE
	DOWNLOAD
	MD5SUM
	DOWNLOAD_x86_64
	MD5SUM_x86_64
	REQUIRES
	MAINTAINER
	EMAIL
};

$arg0 = @ARGV ? $ARGV[0] : undef;
for($arg0) {
	defined || last;
	/^--?(?:v|ver)$/ && do {
		print "$SELF $VERSION\n";
		exit 0;
	};
	/^--?(?:h|help|doc)$/ && do {
		exec("perldoc $0") || die "$SELF: can't exec perldoc\n";
	};
	/^--?(?:m|man)$/ && do {
		exec("pod2man --stderr -s1 -csbo-maintainer-tools -r$VERSION $0") ||
			die "$SELF: can't exec pod2man\n";
	};
}

push @ARGV, "." unless @ARGV;

$errcnt = 0;
fix_info($_) for @ARGV;
exit $errcnt;

sub fix_key {
	my $key = shift;
	$key =~ tr/-a-wyz/_A-WYZ/; # leave "x" lowercase!
	return $key;
}

sub fix_info {
	my $file = shift;
	if(-d $file) {
		my $dir = `realpath $file`;
		chomp $dir;
		(my $name = $dir) =~ s,.*/,,;
		$file = "$dir/$name.info";
	}
	open my $fh, "<$file" or do {
		warn "$SELF: can't read $file: $!\n";
		$errcnt++;
		return;
	};

	my $key = 'INVALID_STUFF';
	my %info;

	# read through the whole file, extracting the values of all the
	# keys, stash them in a hashtable. Multi-valued keys will be stored
	# with carriage returns as a delimiter (they're otherwise not allowed).
	# Quotes, backslashes, etc aren't stored (only the actual values).
	while(<$fh>) {
		chomp;
		s/\r//g; # no DOS line endings
		next if /^\s*$/; # ignore blank lines entirely

		s/(?:^\s+|\s+$)//g; # remove leading/trailing spaces
		s/^(\w+)\s*=\s*/$1=/; # remove spaces around =

		if(/^(\w+)=(.*)$/) {
			$key = $1;
			$val = $2;
			$val =~ s,(?:^['"]|['"]$),,g; # remove quotes around value
			$val =~ s,[\s\\]*$,,; # remove any line-continuation backslash

			$key = fix_key($key);

			if($key =~ /^MD5SUM/) {
				$val =~ tr/A-Z/a-z/;
			}

			# multiple valued keys all on the same line get split up into
			# multi-line values. This only applies to download and md5sum
			# values (which can't contain spaces anyway).
			if($key =~ /^(?:DOWNLOAD|MD5SUM)/) {
				$val =~ s/\s+/\r/g;
			}

			$info{$key} = $val;
		} else {
			s,[\s\\\"]*$,,;
			$info{$key} .= "\r$_";
		}
	}
	close $fh;

	system("mv $file $file.bak");

	open $fh, ">$file" or do {
		warn "$SELF: can't write $file: $!\n";
		$errcnt++;
		return;
	};

	# Reconstitute info file from the values, with correct indentation and
	# quoting, backslashes, etc.
	for $key (@keyorder) {
		$info{$key} ||= ""; # avoid unitialized value on missing key
		my @values = split /\r/, $info{$key};
		if(@values == 0) {
			print $fh "$key=\"\"\n";
		} elsif(@values == 1) {
			print $fh "$key=\"$values[0]\"\n";
		} else {
			my $indent = " " x (length($key) + 2);
			my $first = shift @values;
			my $last = pop @values;
			print $fh "$key=\"$first \\\n";
			print $fh "$indent$_ \\\n" for @values;
			print $fh "$indent$last\"\n";
		}
	}

	my $result = system("diff -u --color $file.bak $file");
	if($result == 0) {
		system("rm $file.bak");
		warn "$SELF: no changes to $file\n";
	}
}