#!/usr/bin/perl
# newentryatom.pl: for each line in diff output beginning with ">", create 
# a new atom entry announcing the creation of a new feed in rss directory. 
# If there are less then $entryCount entries, pad it with older entries
# from $outFileName.

# For demo purposes only. No warrantee expressed or implied.

my $RSSDir = "/usr/www/users/bobd/rss/";

# This is actually used for input purposes, to get old entries for 
# padding if necessary.
my $outFileName = $RSSDir . "newAtomFeeds.atom.bkp";

# Minimum number of entries to keep in feed file. 
my $entryCount = 8;

# How many entries output so far.
my $sourceItemCount = 0;

# How many entries we'll need from the old file. 
my $oldEntriesToKeep = 0;

my $URLStub = "http://www.snee.com/rss/";

my ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = gmtime();
$year += 1900;
my $dateTime = sprintf("%4d-%02d-%02dT%02d:%02d:%02dZ",$year,$mon,$mday,$hour,$min,$sec);

print "<feed xmlns='http://www.w3.org/2005/Atom'>\n";
print "  <id>$outFileName</id>\n";
print "  <title>New Atom feeds in snee.com/rss</title>\n";
print "  <updated>$dateTime</updated>\n";

while (<>) {

    if (s/^>\s*//) { # If the diff output identified this as a new line
	chop($_);
	my $URL = $URLStub . $_ ;
	print "  <entry>\n    <title>new Atom feed: $URL</title>\n";
	print "    <link rel='alternate' type='text/html' href='$URL'/>\n";
	my $ID = $URL;
	$ID =~ s/\/rss\//\/id\//;
	print "    <id>$ID</id>\n";
	print "    <updated>$dateTime</updated>\n";
	print "   </entry>\n";
	$sourceItemCount++;
    }
}

# If we have output less than $oldEntriesToKeep entries, 
# get more from old file.

$oldEntriesToKeep = $entryCount - $sourceItemCount;

if ($oldEntriesToKeep > 0) {
    my $keep = 0;   # Boolean 
    my $retcode = open(INPUT, $outFileName);
    while(<INPUT>) {
	$keep = 1 if ((/<entry/) && ($oldEntriesToKeep > 0));
	print $_ if $keep;
	$oldEntriesToKeep-- if (/<\/entry>/);
    }
    close(INPUT);
}

print "</feed>\n";