#!/usr/bin/perl
#
#
#
use warnings;
use strict;

my $cust_file = "customer.txt";
my $billing_file = "2010.bill";

my $cust;
open (CUST_DATA, $cust_file) || die "Can't read '$cust_file': $!\n";
while (defined (my $line = <CUST_DATA>)) {

    chomp $line; # Remove trailing newline

    my ($cust_id,$cust_name) = split(/:/,$line);

    $cust->{$cust_id}->{name} = $cust_name;

}
close(CUST_DATA);

my @bill_fields = qw(cust_id x_cust_id2 Device_Code Port Traf_Dir x_start_date x_end_date x_number Data_Usage);

my $bill_line;
my $bill_data;
open(BILL_DATA, $billing_file) || die "Can't read '$billing_file': $!\n";
while (defined (my $line = <BILL_DATA>)) {

    chomp $line;

    @{$bill_line}{@bill_fields} = split(/\s/, $line);

    if ( ! $cust->{ $bill_line->{cust_id} }->{name} ) {
        die "$0: Found unknown customer ID [$bill_line->{cust_id}] on line $. of '$billing_file'\n";
    }
    $bill_data->{ $bill_line->{cust_id} }->{ $bill_line->{Device_Code} }->{ $bill_line->{Port} }->{ $bill_line->{Traf_Dir} } = $bill_line->{Data_Usage};

}
close(BILL_DATA);

sub by_name ($$) {
    return $cust->{$a}->{name} <=> $cust->{$b}->{name};
}

for my $customer ( keys %$cust ) {

    print "CUSTOMER NAME: $cust->{$customer}->{name}\n" .
        "Device_Code Port Traf_Dir Data_Usage\n";

    for my $device ( sort by_name keys %{$bill_data->{$customer}} ) {

        for my $port ( sort keys %{$bill_data->{$customer}->{$device}} ) {

            (my $short_port = $port) =~ s/^FastEthernet/Fa/g;

            for my $direction qw(OUT IN) {

                print "$device $short_port $direction " .
                    $bill_data->{$customer}->{$device}->{$port}->{$direction} . $/;

            }

        }

    }

}