#! /usr/bin/perl5


# file : current_parser.pl 
# 
# parses current.conf file
# basically def file for parse function...
# usage : parse_conf(config_file, hash_reference)
#
# Jeff Bloom
# WRD Austin
# jabloom@usgs.gov
#

# &parse_conf("./current.conf");

sub parse_conf {    

  my($config_file) = @_;

  my $key, $value, $multiline_string_flag, $rval, $string_flag; # local vars

  my(%ENV) = %ENV;

  sub true  {1};
  sub false {0};

  if (! open(CONF, $config_file)){

    print STDERR "Unable to open configuration file:\n".
      "\t$config_file\n";

    exit(255);
  }

  $em = '^#';
  while (<CONF>){

    $store_line = $_;

    ++$LINE_NUMBER;

    chomp;

    # we are not in the midst of a quotation ...

    if (! $multiline_string_flag) { 

      next if (/^\s*$/);

      next if (/$em/o); 

      # strip out any comments that dont start lines
		 
      s/^([$em]*)#.*$/$1/o;
	  
      next if (/^\s*$/);

      $rval = ($key, $value) = split('=');

      # not key/value pair ...
      if ($rval != 2) {
	print STDERR 
	  "Unable to parse configuration file line number $LINE_NUMBER:\n".
	    "$store_line\n";

	exit(255);
      }
	    
      $key =~ s/\s+$//; # strip trailing whitespace
	    
      if (exists $ENV{$key}){

	print STDERR "Replacing previously defined variable: $key\n";
      }

      $value =~ s/^\s+//; # strip leading whitespace

      if ($value =~ /^\"/){ # " is this a string definition?

	$string_flag = true;

	$START_STRING_LINE_NUMBER = $LINE_NUMBER;

	if ($value =~ s/^\"([^\"]*)\"(.*)$/$1/) { #"

	  if ($2 =~ /[^\s]+/) {

	    print STDERR "Unrecognized text after close quote on line $LINE_NUMBER\n".
	      "$store_line\n";
	    exit(255);	
	  }
	  $value =~ s/^\s+//;
	} 
	else { # multiline string... 
	  $string_flag = true;
	  $multiline_string_flag = true; 
	  $value =~ s/^\"//; # " strip lead quote mark...
	  $value =~ s/\s+$//; # and trailing whitespace
	  $value .= "\n"; # and append a newline
	  next;
	}
      }
	    
      $value =~ s/\s+$//; # remove trailing whitespace
	   	    
      if (! $string_flag && $value =~ /\s+/){
	print STDERR "spaces found in unquoted string, line number $LINE_NUMBER:\n".
	  "$store_line\n";
	exit;
      }
	    
      while ($value =~ /\[([^\s^\[^\]]*)\]/){

	if (! exists($ENV{$1})){

	  print STDERR 
	    "Undefined variable used in '[variable]' construct,".
	      " line $LINE_NUMBER\n".
		"$store_line\n";
	  exit(255);
	}
	$value =~ s/\[([^\s^\[^\]]*)\]/$ENV{$1}/; 
      }
      
      if ($value =~ /\[|\]/){

	print STDERR "Incomplete bracket pair used on line $LINE_NUMBER\n".
	    "$store_line\n";
	
	exit(255);
      }

      $string_flag = false;

    } 
    # if we are in the midst of a string, look for the end of the string
    else { 

      if (s/([^\"]*)\"(.*)$/$1/){ # "

	if ($2 =~ /[^\s]+/){

	  print STDERR "Unrecognized text after close quote on line $LINE_NUMBER\n".
	      "$store_line\n";
	  exit(255);	
	}

	$value .= $1;

	# Sub in variablename
	while ($value =~ /\[([^\s^\[^\]]*)\]/){

	  if (! exists($ENV{$1})){

	    print STDERR "Undefined variable used in '[variable]' construct,".
	      " line $LINE_NUMBER\n".
		"$store_line\n";
	    
	    exit(255);
	  }
	  $value =~ s/\[([^\s^\[^\]]*)\]/$ENV{$1}/; 
	}

	if ($value =~ /\[|\]/){

	  print STDERR "Incomplete bracket pair used on line $LINE_NUMBER\n".
	    "$store_line\n";
	  
	  exit(255);
	}

	$string_flag = false;
	$multiline_string_flag = false;
      } 
      # if the end is not found, just add this segment to the value.
      else {
	$value .= "$_\n";
	next;
      }

    }

    # Assign the variable
    $$key = $value;
    
    $ENV{$key} = $value;
    
    # print STDOUT "\$$key = \'$value\'\n";


  } 

  ########################################

  if ($multiline_string_flag){

    print STDERR "Incomplete string found in file, ".
      "possibly starting on line $START_STRING_LINE_NUMBER\n";
    exit(255);
  }
 
  return true;

}

1;

__END__