<?php
namespace Deefour;

/*
 * This file is part of the SpellSuggest utility of the Deefour Package.
 *
 * (c) Jason Daly <hide@address.com>
 *
 * This source file is subject to the MIT license that is bundled
 * with this source code in the file LICENSE.
 */
 
/**
 * The SpellSuggest class, part of Deefour's library of utilities.
 * 
 * See README.md or http://github.com/deefour/SpellCheck for more information
 * 
 * @method string  getOriginalText()  Returns the current $_originalText value
 * @method string  getCorrectedText() Returns the current $_correctedText value
 * @method boolean getHasProcessed()  Returns the current $_hasProcessed value
 * 
 * @author Jason 'Deefour' Daly
 * @package Deefour
 * @subpackage SpellSuggest
 * @version 1.0
 */
class SpellCheck{

  /**
   * Stores the original text to later be transformed
   * 
   * @access private
   * @var string
   */
  private $_originalText;

  /**
   * Stores the corrected text; the text transformed by the
   * `SpellSuggest::process()` method.
   * 
   * @access private
   * @var string
   */
  private $_correctedText;

  /**
   * Stores whether or not the current originalText has been processed
   * or not
   * 
   * @access private
   * @var boolean
   */
  private $_hasProcessed = false;

  /**
   * Constructor; optionally sets the originalText value if passed
   * 
   * @param string $string [optional] the text to spellcheck
   * 
   * @return sfDeefourUtilsSpellSuggest instance of $this
   */
  public function __construct($string = null){
    if ($string !== null && is_string($string)) {
      $this->setText($string);
    }
    
    return $this;
  }
  
  /**
   * Sets the original text for this instance
   * 
   * @param string $string the text to spellcheck
   * 
   * @return sfDeefourUtilsSpellSuggest instance of $this
   */
  public function setText($string){
    $this->_hasProcessed = false;
    $this->_correctedText = null;
    $this->_originalText = $string;
    
    return $this;
  }
  
  /**
   * Processes the translation of the originalString into the correctedString,
   * making changes based on the best suggestions for each word returned by the
   * Google Toolbar SpellCheck XML response
   * 
   * @throws 
   * 
   * @return sfDeefourUtilsSpellSuggest instance of $this
   */
  public function process(){
    if ($this->_hasProcessed) {
      return $this->_correctedText;
    } else {
      $this->_correctedText = null;
    }
    
    if ($this->_originalText === null) {
      throw new \BadMethodCallException('There is no original text to spell check.');
    }
  
    $url = 'https://www.google.com/tbproxy/spell?lang=en&hl=en';				
    $request = sprintf('<?xml version="1.0" encoding="utf-8" ?>  
                        <spellrequest textalreadyclipped="0" ignoredups="0" ignoredigits="1" ignoreallcaps="1">  
                          <text>%s</text>  
                        </spellrequest>', $this->_originalText);

    $ch = curl_init($url);
      curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
      curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);
      curl_setopt($ch, CURLOPT_POST, 1);
      curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: text/xml'));
      curl_setopt($ch, CURLOPT_POSTFIELDS, $request);
      curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);

      $output = curl_exec($ch);
    curl_close($ch);
  
    $xml = new \SimpleXMLElement($output);
    $changes = array();
    foreach ($xml->c as $replacements) {
      $start_pos = (int)$replacements['o'];
      $length    = (int)$replacements['l'];
      $replacements = preg_split('/\t/', (string)$replacements);

      $changes[substr($this->_originalText, $start_pos, $length)] = $replacements[0];
    }
  
    $this->_correctedText = strtr($this->_originalText, $changes);
    $this->_hasProcessed = true;
      
    return $this;
  }
  
  /**
   * Boolean test whether or not the corrected version of the text is any different
   * from the original (suggesting a change has been applied). To guarantee the accuracy
   * of the test, `true` will only be returned if the text has actually been spellchecked
   * previously.
   * 
   * @return boolean whether or not the corrected text has changed from the original
   * after the spellcheck has been performed
   */
  public function hasChanged(){
    return strcmp($this->_originalText, $this->_correctedText) !== 0 && $this->_hasProcessed;
  }
  
  /**
   * PHP's magic __toString method...
   * 
   * @return mixed the correctedText string if available, otherwise null
   */
  public function __toString(){
    return (string)$this->_correctedText;
  }
  
  /**
   * PHP's magic __call method; provides functionality of PHP's magic __get()
   * method, with the difference that the user is exepected to request a private
   * variable using a `$instance->getVariableNameHere()` format. The previous
   * example would return some `$_variableNameHere` private variable from the
   * class instance if it existed as a defined property of the class.
   * 
   * @param string $method the method name to transform into the private variable
   * name to check for
   * @param array $arguments [optional] arguments that were passed to the
   * non-existent method
   * 
   * @return mixed the transformed private variable value, otherwise null
   */
  public function __call($method, array $arguments = null){
    $variable = '_' . lcfirst(preg_replace('/^get/', '', $method));

    if (substr($variable, 0, 1) === '_' && strcmp($variable, $method) !== 0 && property_exists($this, $variable)) {
      return $this->$variable;
    }

    throw new \BadMethodCallException('Unknown class method called.');
  }
}