#!/local/perl586/bin/perl

# get-rulemetadata-for-revision -- find out metadata for a given
# rule revision, and store it in the filesystem for later access
# by the ruleqa.cgi web UI.  If the metadata is already in the fsys,
# don't bother re-extracting it, as it's an expensive operation.

# settings are located in $HOME/.corpus

sub usage {
  die qq{
usage: get-rulemetadata-for-revision --rev=NNNNN
        [--outputdir=/path/to/output/dir]
};
}

use strict;
use warnings;
use Getopt::Long;
use File::Path;
use File::Copy;
use Time::ParseDate;
use Cwd;

my $perl = $^X;
my $EARLIEST_REV = 428771;             # before this, mkrules won't work

our ( $opt_outputdir, $opt_rev );
GetOptions(
    "rev=s" => \$opt_rev,
    "outputdir=s" => \$opt_outputdir,
);

$opt_outputdir ||= '.';
$opt_rev or usage();

my $conf_file = "$ENV{HOME}/.corpus";
my $outfile = "$opt_outputdir/rulemetadata.xml";
my %conf;

configure();
if (already_cached()) {
  print "rule metadata already cached: $outfile\n";
  exit;
}

if ($opt_rev < $EARLIEST_REV) {
  print "rule metadata cannot be generated, too early: $outfile\n";
  exit;
}

print "creating rule metadata file: $outfile\n";
my $tmpdir = "/tmp/rulemd.$$";

$SIG{TERM} = $SIG{INT} = sub {
  cleanup_tmpdir(); die "killed";
};

eval {
  svn_and_build();
  copy_md($outfile);
};
if ($@) {
  my $err = $@;
  cleanup_tmpdir();
  die $err;
}

cleanup_tmpdir();
exit;


sub cleanup_tmpdir {
  system ("rm -rf $tmpdir");
}


sub configure {
  # does rough equivalent of source
  open(C, $conf_file) || die "open failed: $conf_file: $!\n";
  my $pwd = getcwd;

  while (<C>) {
    chomp;
    s/#.*//;
    if (/^\s*(.*?)\s*=\s*(.*?)\s*$/) {
      my ($key, $val) = ($1, $2);
      $val =~ s/\$PWD/$pwd/gs;
      $conf{$key} = $val;
    }
  }
  close(C);
}

sub already_cached {
  return (-f $outfile && -s _ > 0);
}

sub svn_and_build {
  mkdir $tmpdir, 0700 or die "cannot mkdir $tmpdir";

  # note: copies .svn dir from the existing SVN checkout;
  # that way, the path and credentials are preserved, just the
  # revision number changes.  In fact, copy the lot; minimize
  # the amount of work that has to be done to "svn up" to the
  # correct revision, hopefully.
  my $cmd;
  $cmd = "cd $tmpdir && ".
        "cp -pr $conf{tree}/. . && ".
        "rm -rf rules rulesrc && ".
        "svn update --non-interactive -r$opt_rev < /dev/null";

  print "[$cmd]\n";
  system $cmd;
  if ($? >> 8 != 0) { die "'$cmd' failed"; }

  $cmd = "cd $tmpdir; ".
        # "$perl Makefile.PL < /dev/null; make; ".
        "$perl build/mkrules --src rulesrc --out rules ".
                "--rulemetadata=rules/rulemetadata.xml";

  print "[$cmd]\n";
  system $cmd;
  if ($? >> 8 != 0) { die "'$cmd' failed"; }
}

sub copy_md {
  my $outfile = shift;
  my $infile = "$tmpdir/rules/rulemetadata.xml";
  if (!-f $infile) {
    die "no $infile!";
  }

  copy ($infile, $outfile) or die "copy $infile $outfile failed";
}