#!/usr/bin/perl

# JKF 2009-08-26 Replace the functionality of lines like this:
# MTA=`perl -n -e 'print "$_" if chomp && s/^\s*MTA\s*=\s*([a-zA-Z]+).*$/$1/ && ($_=lc($_))' /etc/MailScanner/MailScanner.conf`
# with lines like this:
# MTA=`/usr/sbin/ms-peek MTA /etc/MailScanner/MailScanner.conf`
# using a Perl script so that we process 'include' files too.

use FileHandle;
use strict;

# Command-line syntax is this:
if ($ARGV[0] =~ /^-+h(elp)?/) {
  print STDERR "Usage: $0 'Key name' full-path-of-MailScanner-conf-file\n\n";
  exit 1;
}

my %QPConfFilesSeen = ();
my %PercentVars = ();

my $target = shift;
my $filename = shift;

$target =~ s/\s+//g; # Remove all whitespace from conf setting name

print QuickPeek($filename, $target) . "\n";
exit 0;

sub QuickPeek {
  my($filename, $target) = @_;

  my($fh, $key, $value, $targetfound, $targetvalue, $savedline);

  $target = lc($target);        
  $target =~ s/[^%a-z0-9]//g; # Leave % vars intact

  $fh = new FileHandle;
  $fh->open("<$filename") or die "Cannot open config file $filename, $!";

  while(<$fh>) {
    chomp;
    s/#.*$//;
    s/^\s*//g;
    s/\s*$//g;
    next if /^$/;
    $savedline = $_;

    # Implement "include" files
    if ($savedline =~ /^include\s+([^=]*)$/i) {
      my $wildcard = $1;
      my @newfiles = glob($wildcard);
      if (@newfiles) {
        # Go through each of the @newfiles reading conf from them.
        for my $newfile (sort @newfiles) {
          # Have we seen it before?
          #print STDERR "Checking $newfile\n";
          unless ($QPConfFilesSeen{$newfile}) {
            # No, so read it.
            my $ret = QuickPeek($newfile, $target);
            if (defined $ret) {
              $targetfound = 1;
              $targetvalue = $ret;
            }
          }
        }
      }
      # And don't do any more processing on the "include" line.
      next;
    }

    $_ = $savedline;
    $key = undef;   # Don't carry over values from previous iteration
    $value = undef;
    /^(.*?)\s*=\s*(.*)$/;
    ($key,$value) = ($1,$2);

    # Allow %var% = value lines with $VAR in value
    $value =~ s/\%([^%]+)\%/$PercentVars{lc($1)}/g;
    $value =~ s/\$\{?(\w+)\}?/$ENV{$1}/g;
    $value =~ s/\\n/\n/g;
    if ($key =~ /^\%([^%]+)\%$/) {
      # 20090826 Always use the most recent value of %variable%
      #$PercentVars{lc($1)} = $value unless exists $PercentVars{lc($1)};
      $PercentVars{lc($1)} = $value;
      #next; -- Store the percentvars in the key{value} hash as well.
    }

    $key = lc($key);
    $key =~ s/[^%a-z0-9]//g; # Leave numbers and letters only -- leave % vars
    if ($key =~ /^$target$/i) {
      $targetfound = 1;
      $targetvalue = $value;
    }
  }

  $fh->close();

  return $targetvalue;
}