#! /usr/bin/perl -w
#
# Add the GPL to the top of a source file
# the programmer's name is in the "copyright" subroutine.

use strict;
use File::Copy;
use Getopt::Std;
use vars qw($opt_h $opt_C $opt_s $opt_p);

sub usage {
    print <<GROVER_MY_FRIEND;
usage
    $0 [-h]
    $0 {-p "program"} [-C | -s] file_one [ file_two ... ]

	-h		see this help
	-p		The name of the program and what it does
	-C		comment the GPL with C-style comments
	-s		comment it with script-style hashes ('#')
e.g.
    $0 -p "Disk_bigger: a program to enlarge disks" -C ~/src/c/*.c
    $0 -p "beepoften: a script for beeps" -s ~/src/perl/beepoften.pl
GROVER_MY_FRIEND
}
sub help_exit {
    &usage;
    exit;
}

sub copyright {
    #------------get the first line of the copyright, e.g.,
    #------------"Meat_grinder -- a program to grind meat!"
    my $str = shift; 
    $str .= "\n";
    my $date = shift;
    my $programmer = "Ed Cashin";
    $str .= <<GROVER_MY_FRIEND;
Copyright (C) $date $programmer

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

GROVER_MY_FRIEND
    return $str;
}

getopts('hCsp:f:');
if ($opt_h || (!$opt_p)) {	&help_exit; }
my $GPL;
#------------get the year from time
my @timefields = localtime(time);
my $year = splice(@timefields, 5, 1);
#------------make the two-digit year into a four-digit year
$year	+= 1900;
#------------C style comment
if ($opt_C) {
    $GPL = "/*\n";
} 
$GPL .= &copyright($opt_p, $year);
#------------comment it with hashes for scripts
if ($opt_s) {	$GPL =~ s/^/\# /gm; }
#------------C style comment
if ($opt_C) {	$GPL .= "*/\n"; }

foreach (@ARGV) {
    unless ( -f $_ && -r $_ && -w $_ ) {
	warn "Skipping $_.  Check its permissions.\n";
    }
    #---------make the backup
    unless(copy($_, "$_.bkp")) {
	warn "Skipping $_ after failed attempt to back it up.\n$!\n";
	next;
    }
    open INFILE, $_ or die "Couldn't read from $_:  $!\n";
    my @lines = <INFILE>;
    close INFILE;

    open OUTFILE, ">$_" or die "Can't write to $_: $!\n";
    #---------the point at which to insert the GPL:
    my $point = 0;
    #---------skip the shebang line if it's there
    if ($lines[0] =~ m/^\#!/) {	++$point; }
    #---------insert the GPL at $point
    splice(@lines, $point, 0, ($GPL));
    print OUTFILE @lines;
}