use strict;
use warnings;

my( $area_code, $extension ) = ( 333, 321 );

while (<DATA>) {
    my ($number) = $_ =~ /\s([0-9()-]+)/;
    $number =~ s/\D//g;

    if (length( $number ) == 4) {
        $number = $area_code . $extension . $number;
    } elsif (length( $number ) == 7) {
        $number = $area_code . $number;
    } elsif (length( $number ) == 10) {
        # do nothing
    } else {
        warn "could not parse $number\n";
        next;
    }

    $number =~ s/(\d{3})(\d{3})(\d{4})/($1)-$2-$3/;
    $_ =~ s/([0-9()-]+)/$number/;
    print;
}

__DATA__
Black, Joe 0987
Smith, Sue 0534
Brown, Andy 587-0986
Smith, Pam (615)-895-1010