<?php
/*
  Pluralize or Singularize a verb/noun

  Thanks to:
  - http://www.eval.ca/articles/php-pluralize (MIT license)
  - http://dev.rubyonrails.org/browser/trunk/activesupport/lib/active_support/inflections.rb (MIT license)
  - http://www.fortunecity.com/bally/durrus/153/gramch13.html
  - http://www2.gsu.edu/~wwwesl/egw/crump.htm
*/

class Inflector {
  static $plural = array(
    '/(quiz)$/i'               => "$1zes",
    '/^(ox)$/i'                => "$1en",
    '/([m|l])ouse$/i'          => "$1ice",
    '/(matr|vert|ind)ix|ex$/i' => "$1ices",
    '/(x|ch|ss|sh)$/i'         => "$1es",
    '/([^aeiouy]|qu)y$/i'      => "$1ies",
    '/(hive)$/i'               => "$1s",
    '/(?:([^f])fe|([lr])f)$/i' => "$1$2ves",
    '/(shea|lea|loa|thie)f$/i' => "$1ves",
    '/sis$/i'                  => "ses",
    '/([ti])um$/i'             => "$1a",
    '/(tomat|potat|ech|her|vet)o$/i'=> "$1oes",
    '/(bu)s$/i'                => "$1ses",
    '/(alias)$/i'              => "$1es",
    '/(octop)us$/i'            => "$1i",
    '/(ax|test)is$/i'          => "$1es",
    '/(us)$/i'                 => "$1es",
    '/s$/i'                    => "s",
    '/$/'                      => "s"
  );
  
  static $singular = array(
    '/(quiz)zes$/i'             => "$1",
    '/(matr)ices$/i'            => "$1ix",
    '/(vert|ind)ices$/i'        => "$1ex",
    '/^(ox)en$/i'               => "$1",
    '/(alias)es$/i'             => "$1",
    '/(octop|vir)i$/i'          => "$1us",
    '/(cris|ax|test)es$/i'      => "$1is",
    '/(shoe)s$/i'               => "$1",
    '/(o)es$/i'                 => "$1",
    '/(bus)es$/i'               => "$1",
    '/([m|l])ice$/i'            => "$1ouse",
    '/(x|ch|ss|sh)es$/i'        => "$1",
    '/(m)ovies$/i'              => "$1ovie",
    '/(s)eries$/i'              => "$1eries",
    '/([^aeiouy]|qu)ies$/i'     => "$1y",
    '/([lr])ves$/i'             => "$1f",
    '/(tive)s$/i'               => "$1",
    '/(hive)s$/i'               => "$1",
    '/(li|wi|kni)ves$/i'        => "$1fe",
    '/(shea|loa|lea|thie)ves$/i'=> "$1f",
    '/(^analy)ses$/i'           => "$1sis",
    '/((a)naly|(b)a|(d)iagno|(p)arenthe|(p)rogno|(s)ynop|(t)he)ses$/i'  => "$1$2sis",        
    '/([ti])a$/i'               => "$1um",
    '/(n)ews$/i'                => "$1ews",
    '/(h|bl)ouses$/i'           => "$1ouse",
    '/(corpse)s$/i'             => "$1",
    '/(us)es$/i'                => "$1",
    '/s$/i'                     => ""
  );
  
  static $irregular = array(
    "move"   => "moves",
    "foot"   => "feet",
    "goose"  => "geese",
    "sex"    => "sexes",
    "child"  => "children",
    "man"    => "men",
    "tooth"  => "teeth",
    "person" => "people"
  );
  
  static $uncountable = array( 
    "sheep", 
    "fish",
    "deer",
    "series",
    "species",
    "money",
    "rice",
    "information",
    "equipment"
  );
  
  public static function pluralize( $string ) {
    // save some time in the case that singular and plural are the same
    if ( in_array( strtolower( $string ), self::$uncountable ) ) {
      return $string;
    }

    // check for irregular singular forms
    foreach ( self::$irregular as $pattern => $result ) {
      $pattern = "/" . $pattern . "$/i";
        
      if ( preg_match( $pattern, $string ) ) {
        return preg_replace( $pattern, $result, $string);
      }
    }

    // check for matches using regular expressions
    foreach ( self::$plural as $pattern => $result ) {
      if ( preg_match( $pattern, $string ) ) {
        return preg_replace( $pattern, $result, $string );
      }
    }
    
    return $string;
  }
  
  public static function singularize( $string ) {
    // save some time in the case that singular and plural are the same
    if ( in_array( strtolower( $string ), self::$uncountable ) ) {
      return $string;
    }

    // check for irregular plural forms
    foreach ( self::$irregular as $result => $pattern ) {
      $pattern = "/" . $pattern . "$/i";
      
      if ( preg_match( $pattern, $string ) ) {
        return preg_replace( $pattern, $result, $string);
      }
    }
    
    // check for matches using regular expressions
    foreach ( self::$singular as $pattern => $result ) {
      if ( preg_match( $pattern, $string ) ) {
        return preg_replace( $pattern, $result, $string );
      }
    }
    return $string;
  }
  
  public static function pluralize_if($count, $string) {
    if ($count == 1) {
      return "1 $string";
    } else {
      return $count . " " . self::pluralize($string);
    }
  }
}