#!/usr/bin/perl -w

=head1 NAME

numeros - Convert number into Spanish Text (i.e: 501 =
quinientos uno)

=head1 AUTHOR

zeno

=head1 DESCRIPTION

Converts a number into its Spanish text version.
Accepts input either from STDIN or will prompt the user.

=head1 BUGS

Sure to be some.  More than likely I have messed up
the grammar rules a bit on this (I was careful, but
I'm not a native Spanish speaker).

=head1 TO DO

- Version in Catalan
- Fix something with "use locale" to be able to handle
commas and decimals
- Allow a command line parameter to determine gender
(una peseta, un euro)
- Version using one really big regular expression
(I like pain).

=cut

use strict;

my $number;
if (0 == (scalar @ARGV)) {
	print "Número/Number: ";
	$number = <STDIN>;
} else {
	$number = $ARGV[0];
}

if ($number !~ m/^\d+$/) {
  die "usage: numeros num\nWhere num is made up of " .
      "only numbers\nnum sólo puede contener números," .
      " no caracteres\n";
}
my $trans = look_up($number);
print (($trans eq "") ? "cero\n" : "$trans\n");


sub look_up {
  # gets called recursively
  my ($input_number) = @_;

  my @digits=qw(uno dos tres cuatro cinco seis siete ocho
                nueve diez once doce trece catorce quince                       
                dieciséis diecisiete dieciocho diecinueve
                veinte veintiún veintidós veintitrés
                veinticuatro veinticinco veintiséis
                veintisiete veintiocho veintinueve);
  my @tens=qw(treinta cuarenta cincuenta sesenta setenta
              ochenta noventa);
  my $retval;

  if ($input_number == 0) {
    $retval = "";
  } elsif ($input_number < @digits+1) {
    $retval = $digits[$input_number-1];
  } elsif (int($input_number / 10)-3 < @tens) {
    if (($input_number % 10) == 0) {
      $retval = $tens[int($input_number / 10)-3];
    } else {
      $retval = $tens[int($input_number / 10)-3] 
      	." y ". look_up($input_number % 10);
    }
  } elsif ($input_number < 1000) {
    if ($input_number == 100) {
      $retval = "cien";
    } elsif ($input_number < 199) {
      $retval = "ciento " . look_up($input_number % 100);
    } elsif (int($input_number / 100) == 5) {
      $retval = "quinientos" ." "
        . look_up($input_number % 100); 
    } elsif (int($input_number / 100) == 7) {
      $retval = "setecientos" ." "
        . look_up($input_number % 100); 
    } elsif (int($input_number / 100) == 9) {
      $retval = "novecientos" ." "
        . look_up($input_number % 100); 
    } else {
      $retval = look_up(int($input_number / 100)) 
        . "cientos" ." ". look_up($input_number % 100);
    }
  } elsif ($input_number < 1000000) {
    if ($input_number < 2000) {
      $retval = "mil " . look_up($input_number % 1000);
    } else {
      $retval = look_up(int($input_number / 1000)) 
        . " mil " . look_up($input_number % 1000);
    }
  } elsif ($input_number < 1000000000000) {
    if ($input_number < 2000000) {
      $retval = "un millón " 
        . look_up($input_number % 1000000);
    } else {
      $retval = look_up(int($input_number / 1000000)) 
        . " millones " 
        . look_up($input_number % 1000000);
    }
  } elsif ($input_number < 1000000000000000) {
    if ($input_number < 2E12) {
      $retval = "un billón " 
        . look_up($input_number % 1E12);
    } else {
      $retval = look_up(int($input_number / 1E12)) 
        . " billones " 
        . look_up($input_number % 1E12);
    }
  } else {
    $retval = "Overflow/Demasiado grande"
      . " (limite es 999999999999999)";
  }
  return $retval
}