#!/bin/perl


$fp_bool = open(FPW, ">2.vhd"); #vlog
if( $fp_bool == 0 ) {
  print ("by PK open fail file is 2.vhd\n");#vlog
  exit(1);
} 
select(FPW);

$fp_bool = open(FPR, $ARGV[0]);
if( $fp_bool == 0 )
{
  print ("open fail $ARGV[0]\n");
}

$ind_cnt=0;     #indent counter - current
$ind_cntW=0;    #indent counter - current *2
$ind_cntWadj=0; #same as above adjusted to special cases
#buffer that stores words that cause an indent increment.
@ind_inc=
split(/ /, "entity ENTITY BEGIN begin THEN then component COMPONENT case CASE package PACKAGE loop LOOP");
#buffer that stores words that cause an indent decrement.
@ind_dec=
split(/ /, "end END ELSIF elsif");

$cnt_p=0;

$line=<FPR>;
while( eof(FPR) != 1 ) { 
  #update the indent counter
  do ind_cnt_update($ind_cnt);
  $ind_cntW=2*$ind_cnt;

  #remove leading spaces and tabs
  do rm_l_spaces();

  #print the line
  do adj_special_cases($ind_cntW, $ind_cntWadj);
  prt_spaces($ind_cntWadj);
  
# print("($ind_cntW)$line");
# print("($cnt_p $ind_cntW)$line");
  print("$line");

  $line=<FPR>;
}# end while 

sub prt_spaces {
  my($i)="";

  for($i=0; $i<$_[0]; $i++) {
    print(" ");
  }#of for
}

#Works on the the global line: file line buffer.
#Removes leading spaces and tabs.
sub rm_l_spaces {
  while($line =~ /^\t/) {$line =~ s/^\t//g;}
  while($line =~ /^ / ) {$line =~ s/^ //g;}
  #To make sure we get cases with mixed leading space and TAB characters.
  while($line =~ /^\t/) {$line =~ s/^\t//g;}
  while($line =~ /^ / ) {$line =~ s/^ //g;}
}

sub ind_cnt_update {
  my($wd)="";
  my($cnt)="";
  my($line_c)=""; #copy of original line
  my(@line_a)="";
  my($cnt_braces)="";

  #remove remark
  $line_c=$line; #save original
  @line_a=split(/--/, $line);
  $line  =$line_a[0];
# if($line =~ /--/) {die("dbg $line_a[0]-=$line");}

  #count braces 
  do match_braces($cnt_braces);

  #increment
  $cnt=0;
  foreach $wd (@ind_inc) {
    do match_wd_in_line($wd, $cnt);
  }#of foreach
  $_[0] += $cnt_p; #delay one line the increment value.
  if($cnt_braces > 0) {$cnt += $cnt_braces;}
  $cnt_p = $cnt;
  #print("dbg+ $cnt\n");#dbg

  #decrement
  $cnt=0;
  foreach $wd (@ind_dec) {
    do match_wd_in_line($wd, $cnt);
  }#of foreach
  $_[0] -= $cnt; 
  if($cnt_braces < 0) {
    $_[0] += $cnt_braces;
  }
  #print("dbg- $cnt\n");#dbg

  #restore line original value
  $line=$line_c; #save original
}
#Gets a word to look for in the global buffer line.
sub match_wd_in_line {
  my(@a)="";
  my($line_c)=""; #copy of original line

  #We miss cases where a char under search is right at the end for instance
  #consider:"(\n".
  $line_c=$line; #save original
  chomp($line); $line=$line . " \n";
  #The following two are mainly for braces at if/elsif statements.
  $line =~ s/\(/ \( /i;
  $line =~ s/\)/ \) /i;
  $line =~ s/;/ ;/; #This is to help find cases like this "END;".

  #Remove tabs - instead use one space.
  $line =~ s/\t/ /g;

  #component is used to an increment, therefor an "end component" statement
  #causes a bug.
  if($line =~ /(^.*end\s*)(component)(.*)/i) {
    $line = $1 . $3;
  }
  #Same as above with end case.
  if($line =~ /(^.*end\s*)(case)(.*)/i) {
    $line = $1 . $3;
  }
  #Same as above with end loop.
  if($line =~ /(^.*end\s*)(loop)(.*)/i) {
    $line = $1 . $3;
  }

  @a=split(/ /, $line);
  foreach $wd_line (@a) {
    if($_[0] eq $wd_line) {$_[1]+=1;}
  }#of foreach

  $line=$line_c; #restore original
}
sub match_braces {
  my($l)="";
  my($i)="";
  my($ch)="";#char
  my($cnti)="";
  my($cntd)="";

  #count number of ( - number of )
  $l=length($line);
  $c=0;
  for($i=0; $i<=$l; $i++) {
    $ch=substr($line, $i, 1);
    if   ($ch eq "(") {$cnti++;}
    elsif($ch eq ")") {$cntd++;}
  }#of for
  $_[0] = $cnti - $cntd;

}

#In regular indent number
#Out adjusted indent number according to special cases
sub adj_special_cases {
  $_[1]=$_[0]; #default operation
  #else
  if   ($line =~ /^\s*else\s*$/)          {$_[1]=$_[0]-2;}
  elsif($line =~ /^.*\sthen\s.*end\s*if/) {$_[1]=$_[0]+2;}
}