#!/bin/perl

#Perl script to remove unnecessary intra-residue restraints from a DIANA format list
#removes all intraresiudes restraints that are separated by 3 bonds or less
#and all proline intraresidiues, and all intra-ring restraints for Phe and Tyr
#removes HN, HA, HB to HE or HZ in aromatics
#removes i -> i+3 HN->Hns
#removes HN i -> HA i+1

#command line: diana_filt inputfile [>outfile];

#Melanie Nelson
#5/19/99

#use aromlist to clean up filtering
#it is list of aromatic ring protons; restraints within this group on the
#same ring are filtered out
$aromlist = "-HZ-CG-CZ";

open (FILE, $ARGV[0]) ||
	die "Could not open restraint file $ARGV[0]\n";

while (<FILE>){

#save the linput line for easy printing later
	$inline = $_;
	chomp;

#split the line into an array for filtering steps
	@inline = split;

#extra split step so I can just cut and paste in from Randy's ambihnhx-- will fix this later
#to make it nicer.
	@words = split(' ');
   $rNum1 = $words[0]; $rName1 = $words[1]; $aName1 = $words[2];
   $rNum2 = $words[3]; $rName2 = $words[4]; $aName2 = $words[5];

#do the filtering: print by default (flag = 1)
#set flag to zero if an excluding condition is met
	$flag = 1;

#all excluding conditions are intraresidue
	if ($inline[0] == $inline[3]){

#first do the general case intraresidue exclusions (3 bonds or less separating
#the two protons)
#HGs require long way cuz of the aromatics (CG)
		if ($inline[2] eq 'HN' && $inline[5] =~ 'A'){
			$flag = 0;
		} elsif ($inline[2] =~ 'A'){
			if ($inline[5] eq 'HN' || $inline[5] =~ 'B' || $inline[5] =~ 'A'){
				$flag = 0;
			}
		} elsif ($inline[2] =~ 'B'){
			if ($inline[5] =~ 'A' || $inline[5] =~ 'HG' || $inline[5] =~ 'QG' || $inline[5] =~ 'B'){
				$flag = 0;
			}
		} elsif ($inline[2] =~ 'HG' || $inline[2] =~ 'QG'){
			if ($inline[5] =~ 'B' || $inline[5] =~ 'D' || $inline[5] =~ 'HG' || $inline[5] =~ 'QG'){
				$flag = 0;
			}
		} elsif ($inline[2] =~ 'D'){
			if ($inline[5] =~ 'HG' || $inline[5] =~ 'QG' || $inline[5] =~ 'E' || $inline[5] =~ 'D'){
				$flag = 0;
			}
		} elsif ($inline[2] =~ 'E'){
			if ($inline[5] =~ 'D' || $inline[5] =~ 'E'){
				$flag = 0;
			}
		}


#now intra-ring restraints are filtered out
#also filter out special case non-ring intraresidue: Phe/Tyr HB->ring
#protons
		if ($inline[1] eq 'PRO'){
			$flag = 0;
		} elsif ($inline[1] eq 'PHE' || $inline[1] eq 'TYR'){
			if (($aromlist =~ "-$inline[2]") && ($aromlist =~ "-$inline[5]")){
				$flag = 0;
			}
		}

#now include stuff from Randy's ambihnhx script:
#aromatic betas to HEs (CZ) and HZ
   	$flag = 0 if($rNum1 == $rNum2
             && ($aName1 =~ /HN|HA|QPA|HB|MB|QPB/ && $aName2 =~ /CZ|HZ/));
   	$flag = 0 if($rNum1 == $rNum2
             && ($aName2 =~ /HN|HA|QPA|HB|MB|QPB/ && $aName1 =~ /CZ|HZ/));
	}
	
#rest is not intra-residue

	if ($inline[2] eq 'HN' && $inline[5] eq "HN"){
		if ($inline[0]+3 == $inline[3] || $inline[3]+3 == $inline[0]){
			$flag = 0;
		}
	}


#now filter out HN i -> HA or HB i+1
	if (($inline[0]+1 == $inline[3] && $inline[2] eq 'HN' && ($inline[5] =~ 'A' || $inline[5] =~ 'B') ) ||
		($inline[3]+1 == $inline[0] && $inline[5] eq 'HN' && ($inline[2] =~ 'A' || $inline[5] =~ 'B'))){
		$flag = 0;
	}



	if ($flag == 1){ print $inline }

}