#!/usr/local/bin/perl -w

if (@ARGV == 0) {
    die "usage: update_copyrights <copyright_text>";
}
@copyright_text = ();
open(COPYRIGHT, "<$ARGV[0]") || die "can't open $ARGV[0]: $!";
@copyright_text = <>;
close(COPYRIGHT);

while (<>) {
    ($file, $years_list) = split(/\s+/);
    @years = split(/,/, $years_list);

    if ( ! -f $file ) {
	print "$file: missing\n";
    }
    if ($years_list eq "SKIP") {
	print "$file: SKIP\n";
	next;
    }

    if ($file =~ /\.[chy]$/) {
	$c_comment = 1;
    } else {
	die "only C comments are supported right now";
    }
    open(SOURCE, "<$file") || die "can't open $file: $!";
    $_ = <SOURCE>;
    if (/^\/\*/) {
	$_ = <SOURCE>;
	if ($_ !~ /[Cc]opyright/) {
	    print "$file: non-copyright comment\n";
	    close(SOURCE);
	    next;
	}
	if ($_ !~ /\*\//) {
	    while (<SOURCE>) {
		if ($_ =~ /\*\//) {
		    last;
		}
	    }
	}
	$first = "";
    } else {
	$first = $_;
    }
    open(TARGET, ">$file.new") || die "can't open $file.new: $!";
    if ($c_comment) {
	print TARGET "/*\n";
	$prefix = " * ";
    }
    print TARGET "${prefix}Copyright (C) ";
    $first_year = 1;
    foreach $year (@years) {
	if (! $first_year) {
	    print TARGET ", ";
	}
	print TARGET "$year";
	$first_year = 0;
    }
    print TARGET "  Internet Software Consortium.\n";
    print TARGET "$prefix\n";
    foreach $_ (@copyright_text) {
	print TARGET "${prefix}$_";
    }
    if ($c_comment) {
	print TARGET " */\n";
    }
    if ($first ne "") {
	print TARGET $first;
    }
    while (<SOURCE>) {
	print TARGET $_;
    }
    close(TARGET);
    close(SOURCE);
    rename("$file", "$file.bak") || die "rename($file, $file.bak): $!";
    rename("$file.new", "$file") || die "rename($file.new, $file): $!";
}