#!/usr/bin/perl

#
# These variables can be edited by the user to change the generated
# configuration files.
#
$name      = darwin;           # base hostname
$subnet    = "10.0.0";         # subnet for hosts (must be in format
"XXX.XXX.XXX")
$node      = 77;                  # starting node number
$dest      = "config_files";   # destination directory for generated files
$sn_prefix = "QP";             # prefix for serial numbers, may be left
blank
$sn_suffix = "PMX";            # suffix for serial numbers, may be left
blank

#
# END OF USER CONFIGURABLE OPTIONS
#

$subnet .= '.';

#
# replace "." with "\." so "." is treated literally in the pattern
#
($subnet_pattern = $subnet) =~ s/\./\\\./g;

# 
# This is a list of IP address on the subnet that we should not replace with
# the host IP address since we do a general search and replace on the string
# "$subnet.*".  Here we exclude the router and NTP server IP addresses.
#
@exclude_ips = ( "254", "106" );

foreach ( @exclude_ips ) {
    $_ = "$subnet_pattern$_";
}

$exclude_pattern = join( "|", @exclude_ips );

#
# read in the template
#
@template;
$file = "template.plist";
open( TEMPLATE, "<$file" ) or die "Failed to open $file: $!";

while ( <TEMPLATE> ) {
    push( @template, $_ );
}
close( TEMPLATE );

#
# read in the serial numbers
#
@serials;
$file = "serial_numbers";
open( SERIALS, "<$file" ) or die "Failed to open $file: $!";

while ( <SERIALS> ) {
    chomp;
    push( @serials, $_ );
}
close( SERIALS );

$n_serials = $#serials + 1;
print "Loaded $n_serials serial numbers\n";

if ( ! -d "config_files" ) {
    printf "Creating destination directory $dest\n";
    mkdir( "$dest", 0777 ) or die "Failed to mkdir() for $dest: $!";
}

#
# create the configuration files, one for each serial number we read
# in starting with the node number specified above
#
foreach ( @serials ) {
    $hostname = sprintf( "$name%03d", $node );
    $address  = "$subnet$node";
    $file     = "$dest/$sn_prefix$_.plist";

    if ( -f $file ) {
        print "Updating configuration $hostname ($sn_prefix$_$sn_suffix)\n";
    } else {
        print "Generating configuration $hostname
($sn_prefix$_$sn_suffix)\n";
    }

    open( CONFIG, ">$file" ) or die "Failed to open $file: $!";
    select( CONFIG );

    foreach ( @template ) {
        s/$name[0-9]{3}/$hostname/o;
        s/$subnet_pattern[0-9]{1,3}/$address/o unless /$exclude_pattern/o;
        print $_;
    }
    close( CONFIG );
    select( STDOUT );

    ++$node;
}