#!/usr/bin/perl

=head1 NAME

mr - a Multiple Repository management tool

=head1 SYNOPSIS

B<mr> [options] checkout

B<mr> [options] update

B<mr> [options] status

B<mr> [options] commit [-m "message"]

B<mr> [options] action [params ...]

=head1 DESCRIPTION

B<mr> is a Multiple Repository management tool. It allows you to register a
set of repositories in a .mrconfig file, and then checkout, update, or
perform other actions on all of the repositories at once.

Any mix of revision control systems can be used with B<mr>, and you can
define arbitrary actions for commands like "update", "checkout", or "commit".

The predefined commands should be fairly familiar to users of any revision
control system:

=over 4

=item checkout

Checks out all the registered repositories that are not already checked
out.

=item update

Updates each registered repository from its configured remote repository.

If a repository isn't checked out yet, it will first check it out.

=item status

Displays a status report for each registered repository, showing what
uncommitted changes are present in the repository.

=item commit

Commits changes to each registered repository. (By default, changes
are pushed to the remote repository too, when using distributed systems
like git.)

The optional -m parameter allows specifying a commit message.

=head1 OPTIONS

=over 4

=item -d directory

Specifies the topmost directory that B<mr> should work in. The default is
the current working directory. B<mr> will operate on all registered
repositories at or under the directory.

=item -c mrconfig

Use the specified mrconfig file, instead of looking for on in your home
directory.

=item -v

Be verbose.

=back

=head1 FILES

B<mr> is configured by .mrconfig files. It searches for .mrconfig files in
your home directory, and in the root directory of each repository specified
in a .mrconfig file. So you could have a ~/.mrconfig that registers a
repository ~/src, that itself contains a ~/src/.mrconfig file, that in turn
registers several additional repositories.

The .mrconfig file uses a variant of the INI file format. Lines starting with
"#" are comments. Lines ending with "\" are continued on to the next line.
Sections specify where each repository is located, relative to the
directory that contains the .mrconfig file.

Within a section, each parameter defines a shell command to run to handle a
given action. Note that these shell commands are run in a "set -e" shell
environment, where any additional parameters you pass are available in
"$@". B<mr> cds into the repository directory before running
a command, except for the "checkout" command, which is run in the parent
of the repository directory, since the repository isn't checked out yet.

There are two special parameters. If the "skip" parameter is set and
its command returns nonzero, then B<mr> will skip acting on that repository.

The "default" section allows setting up default handlers for each action,
and is overridden by the contents of other sections. mr contains default
handlers for the "update", "status", and "commit" actions, so normally
you only need to specify what to do for "checkout".

For example:

  [src]
  checkout = svn co svn://svn.example.com/src/trunk src

  [src/linux-2.6]
  # only check this out on kodama
  skip = test $(hostname) != kodama
  checkout = git clone git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git

=head1 AUTHOR

Copyright 2007 Joey Hess <joey@kitenet.net>

Licensed under the GNU GPL version 2 or higher.

http://kitenet.net/~joey/code/mr/

=cut

use warnings;
use strict;
use Getopt::Long;
use Cwd qw(getcwd abs_path);

my $directory=getcwd();
my $config="$ENV{HOME}/.mrconfig";
my $verbose=0;
my %config;

Getopt::Long::Configure("no_permute");
my $result=GetOptions(
	"d=s" => sub { $directory=abs_path($_[1]) },
	"c=s" => \$config,
	"v" => \$verbose,
);
if (! $result || @ARGV < 1) {
	die("Usage: mr [-d directory] action [params ...]\n");
}
my $action=shift @ARGV;

loadconfig(\*DATA);
loadconfig($config);
#use Data::Dumper;
#print Dumper(\%config);

my (@failures, @successes, @skipped);
my $first=1;
foreach my $topdir (sort keys %config) {
	foreach my $subdir (sort keys %{$config{$topdir}}) {
		next if $subdir eq 'default';
		
		my $dir=$topdir.$subdir;

		if (defined $directory &&
		    $dir ne $directory &&
		    $dir !~ /^\Q$directory\E\//) {
			print "mr $action: $dir skipped per -d parameter ($directory)\n" if $verbose;
			push @skipped, $dir;
			next;
		}

		print "\n" unless $first;
		$first=0;

		if (exists $config{$topdir}{$subdir}{skip}) {
			my $ret=system($config{$topdir}{$subdir}{skip});
			if ($ret >> 8 == 0) {
				print "mr $action: $dir skipped per config file\n" if $verbose;
				push @skipped, $dir;
				next;
			}
		}

		action($action, $dir, $topdir, $subdir);

	}
}

sub action {
	my ($action, $dir, $topdir, $subdir) = @_;

	if ($action eq 'checkout') {
		if (-d $dir) {
			print "mr $action: $dir already exists, skipping checkout\n";
			push @skipped, $dir;
			next;
		}
		$dir=~s/^(.*)\/[^\/]+\/?$/$1/;
	}
	if ($action eq 'update') {
		if (! -d $dir) {
			return action("checkout", $dir, $topdir, $subdir);
		}
	}

	if (! chdir($dir)) {
		print STDERR "mr $action: failed to chdir to $dir: $!\n";
		push @skipped, $dir;
	}
	elsif (! exists $config{$topdir}{$subdir}{$action}) {
		print STDERR "mr $action: no defined $action command for $topdir$subdir, skipping\n";
		push @skipped, $dir;
	}
	else {
		print "mr $action: in $dir\n";
		my $command="set -e; my_action(){ $config{$topdir}{$subdir}{$action} ; }; my_action @ARGV";
		my $ret=system($command);
		if ($ret != 0) {
			print STDERR "mr $action: failed to run: $command\n" if $verbose;
			push @failures, $topdir.$subdir;
			if ($ret >> 8 != 0) {
				print STDERR "mr $action: command failed\n";
			}
			elsif ($ret != 0) {
				print STDERR "mr $action: command died ($ret)\n";
			}
		}
		else {
			push @successes, $dir;
		}
	}
}

sub showstat {
	my $count=shift;
	my $singular=shift;
	my $plural=shift;
	if ($count) {
		return "$count ".($count > 1 ? $plural : $singular);
	}
	return;
}
print "\nmr $action: finished (".join("; ",
	showstat($#successes+1, "success", "successes"),
	showstat($#failures+1, "failure", "failures"),
	showstat($#skipped+1, "skipped", "skipped"),
).")\n";
exit @failures ? 1 : 0;

my %loaded;
sub loadconfig {
	my $f=shift;

	my @toload;

	my $in;
	my $dir;
	if (ref $f eq 'GLOB') {
		$in=$f;	
		$dir="";
	}
	else {
		# $f might be a symlink
		my $absf=abs_path($f);
		if ($loaded{$absf}) {
			return;
		}
		$loaded{$absf}=1;

		print "mr: loading config $f\n" if $verbose;
		open($in, "<", $f) || die "mr: open $f: $!\n";
		($dir)=$f=~/^(.*\/)[^\/]+$/;
		if (! defined $dir) {
			$dir=".";
		}
		$dir=abs_path($dir)."/";

		# copy in defaults from first parent
		my $parent=$dir;
		while ($parent=~s/^(.*)\/[^\/]+\/?$/$1/) {
			if (exists $config{$parent} &&
			    exists $config{$parent}{default}) {
				$config{$dir}{default}={ %{$config{$parent}{default}} };
				last;
			}
		}
	}

	my $section;
	while (<$in>) {
		chomp;
		next if /^\s*\#/ || /^\s*$/;
		if (/^\s*\[([^\]]*)\]\s*$/) {
			$section=$1;
			if (length $dir && $section ne "default" &&
			    -e $dir.$section."/.mrconfig") {
				push @toload, $dir.$section."/.mrconfig";
		        }
		}
		elsif (/^\s*(\w+)\s*=\s*(.*)/) {
			my $parameter=$1;
			my $value=$2;

			# continuation line
			while ($value=~/(.*)\\$/) {
				$value=$1.<$in>;
				chomp $value;
			}

			if (! defined $section) {
				die "$f line $.: parameter ($parameter) not in section\n";
			}
			if (! exists $config{$dir}{$section} &&
			      exists $config{$dir}{default}) {
				# copy in defaults
				$config{$dir}{$section}={ %{$config{$dir}{default}} };
			}
			$config{$dir}{$section}{$parameter}=$value;
		}
		else {
				die "$f line $.: parse error\n";
		}
	}
	close $in;

	foreach (@toload) {
		loadconfig($_);
	}
}

__DATA__
# Some useful actions that mr knows about by default.
# These can be overridden in ~/.mrconfig.
[default]
update = \
	if [ -d .svn ]; then \
		svn update; \
	elif [ -d .git ]; then \
		git pull origin master; \
	else \
		echo "mr update: unknown RCS"; \
		exit 1; \
	fi
status = \
	if [ -d .svn ]; then \
		svn status; \
	elif [ -d .git ]; then \
		git status || true; \
	else \
		echo "mr status: unknown RCS"; \
		exit 1; \
	fi
commit = \
	if [ -d .svn ]; then \
		svn commit "$@"; \
	elif [ -d .git ]; then \
		git commit -a "$@"; \
	else \
		echo "mr commit: unknown RCS"; \
		exit 1; \
	fi