#!/usr/bin/perl

$filename ="reklama.dat";
$MAXLINES=2; # number of lines of ad content
$MAXCHAR =35; # numbers of characters per a line of ads 

# This program is written by M. Verbitsky under GNU Public License
# version 1.01, August 2000
# usage: <!--#include virtual="/cgi/reklama2.cgi?3"-->
# (for 3 lines of slogans)



$maxlines = $ENV{'QUERY_STRING'};

if ($maxlines>0) {$MAXLINES=$maxlines;}


########################################
open(REKLAMA, "< $filename") 
                   || die ("couldn't open $filename: $!\n");
@filecontents =<REKLAMA>;
close(REKLAMA);

# format reklamy:
# URL
# slogan
# [optional] coefficient (naskol'ko chasto ego puskat')
# slogan
# [optional] coefficient 
# slogan...
# [optional] coefficient 
# URL
# (etc.)


$wnumber=0; # weighted number (with coefficients)
$cont_slogan=();
$cont_url=();
$cont_coeff=();
$url="http://imperium.lenin.ru";

# parsing the ads list
while (@filecontents>1)
	{    
		comments_remove();
		$mightbe_url = ($filecontents[0]);
		$test = substr ($mightbe_url, 0, 7);
	        if ("$test" eq "http://")
			{
				$url=$mightbe_url;
				shift(@filecontents);
				comments_remove();
			} 
		$slogan=shift(@filecontents);
		comments_remove();
	        $mightbe_coeff=$filecontents[0];
	        if ($mightbe_coeff != 0) 	# esli ehto ne stroka, a nomer 
			{
				$coeff=$mightbe_coeff;
	                        shift(@filecontents);
			}  else {$coeff =1;}
# modify the global parameters
		$wnumber += $coeff;
#creating contents list
		push(@cont_slogan, $slogan);
		push(@cont_url, $url);
		push(@cont_coeff, $coeff);
	} 
# we constructed three lists of ad contents

# printing the results of parsing -- commented below
# print @cont_slogan; print @cont_url; print @cont_coeff;
#$number=@cont_slogan; print "\n\nthe number of slogans is $number\n";
#$number=@cont_url; print "the number of urls is $number\n";
#$number=@cont_coeff; print "the number of coeff is $number\n"; 
#print "all three numbers should be equal!\n";
#print "the total coefficient is $wnumber\n";

@reklama=();
$numlines =0;
while ($numlines < $MAXLINES && @cont_slogan>0)
   { 
        my $line;
# print "running oneline";
	$line=oneline();
# print "$line";
	push(@reklama, $line);
	++$numlines;
   }


print "Content-type:text/html; charset=koi8-r\n\n";
print @reklama;


###########################
#####  	ROUTINES  #########

# creating just one line of adverts, returning this line

sub oneline()
{
	$line ="";
	$razdelitel ="";
	$current_line_length =0;
        while (@cont_slogan && $current_line_length<$MAXCHAR) 
         {
	   choose();
# now removing the trailing whitespace
	   $url =~ s/ +$//g; $slogan =~ s/ +$//g;
	   $current_line_length += length($slogan);
	   $line = $line.$razdelitel."<A HREF=".$url.">".$slogan."</a>";
	   $razdelitel=" | \n";
         } 
	$line = $line."<br>\n";
	return($line);
}




# function choose determines the number 
# of the ad and removes the corr. listing from the three lists
# it writes its results in $url and $slogan

sub choose ()
{ 
	$rnd = rand($wnumber);
	$choice =0;
	$test=0;
	@coeff_list= @cont_coeff;
	while ($test+@cont_coeff[$choice] < $rnd && defined(@cont_coeff[$choice])) 
		{ 
			$test+= @cont_coeff[$choice];
#print "test is $test, choice is $choice\n";
			++$choice;
		}
	if (!defined(@cont_coeff[$choice])) {$choice=@cont_coeff;} # sanity check
	$wnumber -= @cont_coeff[$choice]; #total coefficient is decreased
	$slogan=splice(@cont_slogan, $choice, 1);
	$url=splice(@cont_url, $choice, 1 );
	splice(@cont_coeff, $choice, 1);
#$huj =@cont_coeff;
#print "wnumber =$wnumber, rnd is $rnd, choice is $choice, test is $test, cont_coeff is $huj long\n";
#print "slogan is $slogan url is $url\n";
}

sub comments_remove ()
{                       
			while  (($filecontents[0] =  		
                            substr ($filecontents[0], 0,
                            index($filecontents[0],"\#"))) =~m/\S/==0)
			   
			{ 
				shift(@filecontents); 
				if (@filecontents==0) {return;}
			} 
			$filecontents[0]= $filecontents[0]." "; 
					#this is a cludge
}	
# removing the comments and all the empty strings
# now $filecontents[0] is non-empty and has all comments removed