#!/usr/bin/perl
#
use strict;
use warnings;
use Text::CSV;

$ARGV[0] or die "Usage: $0 <filename> [<filename>] ...";

my ( $template_file_name, $templateText, %hash ) = '';

my $csv = Text::CSV_XS->new ({ binary => 1, auto_diag => 2, })
  or die "Cannot use CSV: " . Text::CSV->error_diag();

for my $csvFile (@ARGV) {
	print "\nProcesing file $csvFile ...\n";
	open my $csvfh, '<', $csvFile or die "Unable to open $csvFile: $!";

	# Ignore column names in first line
	my $columnNames = $csv->getline($csvfh);

	# Get vars from second line
	my @vars = @{ $csv->getline($csvfh) };

	# Process each csv line
	while ( my $row = $csv->getline($csvfh) ) {
        next unless @$row;
        my $templateFN = pop @$row;

		if ( $template_file_name ne $templateFN ) {
			$template_file_name = $templateFN;
			undef $templateText;
		}
		
		# keys: fields from second line; values: fields from csv line
		@hash{@vars} = @$row;

		$templateText //= getTemplateText($template_file_name);
		my $templateTextCopy = $templateText;

		$templateTextCopy =~ s/$_/$hash{$_}/g for keys %hash;

		my $ofile_name = $hash{'##rtrname##'} . '.txt';

		print "Writing to file: $ofile_name\n";
		open my $fh, '>', $ofile_name or die "$ofile_name: $!";
		print $fh $templateTextCopy;
		close $fh;
	}

	close $csvfh;
}

print "\nDone!\n";

sub getTemplateText {
	my ($template_file_name) = @_;

	local $/;
	open my $fh, '<', $template_file_name or die "$template_file_name: $!";
	$templateText = <$fh>;
	close $fh;

	return $templateText;
}


##</code><code>##

Location,Router Name,Loopback IP,OSPF Process ID,OSPF Area,Network,Mask,GIG0/0 IP Address,0/0 Subnet Mask,Template
##location##,##rtrname##,##loop0-ip##,##ospf-id##,##ospf-area##,##ospf-network##,##ospf-mask##,##eth00-ip##,##eth00-sm##,
Sydney,SYD-RTR-001,192.168.15.1,99,0,172.25.16.0,0.0.0.255,172.25.16.6,255.255.255.0,router