#!/usr/bin/perl
###############################################################################
#
# name:       txtSub.pl
#
# usage:      txtSub.pl -th <str1> <str2> <insert file> <file1>
#                       [<file2> ...<fileN>]
#
# decription: substitute text in list of files.
#             the text contained in <insert file> will be inserted in all 
#             files, in the place of the text included between the first line
#             that contains <str1> and the first line that contains <str2>. 
#
# author:     paolo guiducci
#
# Disclaimer: You are free to use this code, being understood that I decline
#             any responsibility, direct or implied, for damages or 
#             inconveniences that its use or impossibility of use may cause
#             (directly or indirectly). If your local law does not allow a full
#             decline of responsibility by the author of a software that you
#             use, then you are not allowed to use this code or any part of it. 
#
# web:        http://pguiducci.com
###############################################################################

use Getopt::Std;

getopts("th") or usage();

if ($opt_h || @ARGV < 4) {usage()};

my $str1 = shift(@ARGV);
my $str2 = shift(@ARGV);
my @fileIn=();
my @fileOut=();

$textFile = shift @ARGV;
my $rFileIns=loadText();

confirm();

print "\n\n";

foreach $fileArg (@ARGV) {
   if (!-w $fileArg) {
      print "warning: $fileArg doesn't exist or not writable\n";
      next;
   }
   
   open(IN, "$fileArg") || print "can't open file $fileArg\n";
   @fileIn = <IN>;
   close IN;

   $indMax = @fileIn;
   @fileOut = ();
   $ind = 0;
   
   ### Firt part loop
   until ($ind >= $indMax || $fileIn[$ind] =~ /$str1/) {
      push(@fileOut, $fileIn[$ind]);
      $ind++;
   }

   if ($ind >= $indMax) {
      print "$fileArg --> skipped, 1st string not found!\n";
      next;
   }
   
   ### Insert text
   push(@fileOut, @$rFileIns);
   
   ### Skip lines loop
   until ($ind >= $indMax || $fileIn[$ind] =~ /$str2/) {
      $ind++;
   }
 
   if ($ind >= $indMax) {
      print "$fileArg --> changed, 2nd string not found!\n";
      next;
   }

   $ind++;

   ### Last part loop
   until ($ind >= $indMax) {   
      push(@fileOut, $fileIn[$ind]);
      $ind++
   }
   
   if ($opt_t) {
      print "test updated file: $fileArg\n";
      print 
   } else {
      open (OUT, "> $fileArg") or die "unable to open $fileArg in output mode";
      print OUT @fileOut;
      close OUT;
      print "updated file: $fileArg\n";
   }
}

print "\n";


###################
### Subroutines ###
###################

sub loadText {
   open(F_TEXT, "$textFile" ) || die "can't open file $textFile" ;
   my @file = <F_TEXT>;
   close F_TEXT;
   return \@file;
}

sub confirm {
   print "\nlist of files to be changed:\n\n";
   foreach $ln (@ARGV) {
      print "   $ln\n"
   }

   print "\nfrom string: $str1\n";
   print "to string:   $str2\n";

   print "\ntext to be inserted:\n\n";
   foreach $ln (@$rFileIns) {
      print "   $ln"
   }

  print "\n";   
   do {
      if (!$opt_t) {
         print "\nreal mode!";
      }
      else {
         print "\ntest mode";
      }
      print ", confirm? ";
      chomp ($conf = <STDIN>);
   } until ($conf =~ /[yn]/);
   if ($conf ne "y") {
      exit;
   }
}

sub usage {
   print "usage txtSub.pl -th <str1> <str2> <insert file> <file1> [<file2> ... <fileN>]\n";
   exit;
}