&Generate_Userid

=head2 Generate_Userid

    my $newuid = Generate_Userid($borrowernumber, $firstname, $surname);

    Generate a userid using the $surname and the $firstname (if there is a value in $firstname).

    $borrowernumber is optional (i.e. it can contain a blank value). A value is passed when generating a new userid for an existing borrower. When a new userid is created for a new borrower, a blank value is passed to this sub.

    return :

        new userid ($firstname.$surname if there is a $firstname, or $surname if there is no value in $firstname) plus offset (0 if the $newuid is unique, or a higher numeric value if not unique).

=cut

sub Generate_Userid {

  my ($borrowernumber, $firstname, $surname) = @_;

  my $newuid;

  my $offset = 0;

  my $patron = Koha::Patron->new;

  #The script will "do" the following code and increment the $offset until the generated userid is unique

  do {

    $firstname =~ s/[[:digit:][:space:][:blank:][:punct:][:cntrl:]]//g;

    $surname =~ s/[[:digit:][:space:][:blank:][:punct:][:cntrl:]]//g;

    $newuid = lc(($firstname)? "$firstname.$surname" : $surname);

    $newuid = unac_string('utf-8',$newuid);

    $newuid .= $offset unless $offset == 0;

    $patron->userid( $newuid );

    $offset++;

   } while (! $patron->has_valid_userid );

   return $newuid;

}

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