/**
* Convert number to word
* http://www.karlrixon.co.uk/writing/convert-numbers-to-words-with-php/ (originally convert_number_to_words)
*
* Examples:
* echo Numbers::toWord(123456789);
* one hundred and twenty-three million, four hundred and fifty-six thousand, seven hundred and eighty-nine
*
* echo Numbers::toWord(123456789.123);
* one hundred and twenty-three million, four hundred and fifty-six thousand, seven hundred and eighty-nine point one two three
*
* echo Numbers::toWord(-1922685.477);
* negative one million, nine hundred and twenty-two thousand, six hundred and eighty-five point four seven seven
*
* float rounding can be avoided by passing the number as a string
* echo Numbers::toWord(123456789123.12345); // rounds the fractional part
* one hundred and twenty-three billion, four hundred and fifty-six million, seven hundred and eighty-nine thousand, one hundred and twenty-three point one two
*
* echo Numbers::toWord('123456789123.12345'); // does not round
* one hundred and twenty-three billion, four hundred and fifty-six million, seven hundred and eighty-nine thousand, one hundred and twenty-three point one two three four five
*
* @param $number
* @return bool|mixed|null|string
* @throws \Exception
*/
public static function toWord($number)
{
$hyphen = '-';
$conjunction = ' and ';
$separator = ', ';
$negative = 'negative ';
$decimal = ' point ';
$dictionary = self::toWordDictionary();
if (!is_numeric($number)) {
return false;
}
if ($number >= 0 && (int) $number < 0 || (int) $number < 0 - PHP_INT_MAX) {
throw new \Exception(__METHOD__ . ' only accepts numbers between -' . PHP_INT_MAX . ' and ' . PHP_INT_MAX);
}
if ($number < 0) {
return $negative . Numbers::toWord(abs($number));
}
$string = $fraction = null;
if (strpos($number, '.') !== false) {
list($number, $fraction) = explode('.', $number);
}
switch (true) {
case $number < 21:
$string = $dictionary[$number];
break;
case $number < 100:
$tens = (int) ($number / 10) * 10;
$units = $number % 10;
$string = $dictionary[$tens];
if ($units) {
$string .= $hyphen . $dictionary[$units];
}
break;
case $number < 1000:
$hundreds = $number / 100;
$remainder = $number % 100;
$string = $dictionary[$hundreds] . ' ' . $dictionary[100];
if ($remainder) {
$string .= $conjunction . Numbers::toWord($remainder);
}
break;
default:
$baseUnit = pow(1000, floor(log($number, 1000)));
$numBaseUnits = (int) ($number / $baseUnit);
$remainder = $number % $baseUnit;
$string = Numbers::toWord($numBaseUnits) . ' ' . $dictionary[$baseUnit];
if ($remainder) {
$string .= $remainder < 100 ? $conjunction : $separator;
$string .= Numbers::toWord($remainder);
}
break;
}
if (null !== $fraction && is_numeric($fraction)) {
$string .= $decimal;
$words = array();
foreach (str_split((string) $fraction) as $number) {
$words[] = $dictionary[$number];
}
$string .= implode(' ', $words);
}
return $string;
}