#!/usr/bin/perl -w
#
# phone number formatter

use strict;

my @numbers = ('0208 477 1376', '080 080 080 0', '0845 07 98 666', 
               '0796 87 28 601', '01787 278545'); 
# need 01x1 and 011x test cases, and more 08 test cases

foreach my $phone (@numbers) {
    $phone =~ s/ //g; # remove the idiotic pre-formatting
    
    my ($code, $local_code, $local_number);
    if ($phone =~ m/(02\d)(\d+)/) {
        # london/cardiff/new location numbers: 3 4 4, 3 3 4
        # note that I count 0 as part of the code here
        $code = $1;
        ($local_code, $local_number) = nice_split($2);
    } elsif ($phone =~ m/(0[38]\d\d|01\d1|011\d)(\d+)/) {
        # newish location numbers with three digit codes starting 1, and
        # 08/03 non geographic numbers: 4 3 3, 4 3 4, 4 4 4
        $code = $1;
        ($local_code, $local_number) = nice_split($2);
    } else {
        $phone =~ m/(0\d{4})(\d+)/;
        # everything else, like mobile numbers
        # 5 3 3 or 5 3 4
        $code = $1;
        ($local_code, $local_number) = nice_split($2);
    }
    
    print "$phone  -> ($code) $local_code $local_number\n";
}

sub nice_split {
    my $number = shift;                
    my $split_at_char = int(length($number)/2);
    $number =~ m/(\d{$split_at_char})(\d+)/;
    return ($1, $2);
}