sub callbacks_for_today {

    my $username = shift or confess 'must supply username';

    ["
SELECT
  *
FROM
  call_schedule
  INNER JOIN person ON (user_people_id=people.id)
WHERE
  DATE_FORMAT( `callback_time` , '%Y-%m-%d' ) = DATE_FORMAT( NOW( ) , '%Y-%m-%d' ) -- date_clause
  AND staff_people_id = users.people_id
  AND username =", \$username,
"
ORDER BY
  callback_time DESC
    "]

}


##</code><code>##

sub swap_sql {
    my ($sql_fragment, $sub_hint, $sub_expr) = @_;

    $sub_hint = "^.+-- $sub_hint";

    # return data structures as is
    ref $sql_fragment and return $sql_fragment;

    $sql_fragment =~ s/$sub_hint/$sub_expr/m ;
    $sql_fragment;
}


##</code><code>##


sub callbacks_for_tomorrow {

    my $username = shift or confess 'must supply username';

    my $today_sql = callbacks_for_today($username);
    my $tomorrow_date_str = "DATE_FORMAT( `callback_time` , '%Y-%m-%d' ) = DATE_FORMAT( DATE_ADD(NOW( ), INTERVAL 1 DAY) , '%Y-%m-%d' ) -- date_clause";

    my @tomorrow_sql = map (swap_sql($_, 'date_clause', $tomorrow_date_str), @$today_sql);

     \@tomorrow_sql;
}