<?php

/*
 +-----------------------------------------------------------------------+
 | program/include/rcube_string_replacer.php                             |
 |                                                                       |
 | This file is part of the Roundcube Webmail client                     |
 | Copyright (C) 2009, The Roundcube Dev Team                            |
 | Licensed under the GNU GPL                                            |
 |                                                                       |
 | PURPOSE:                                                              |
 |   Handle string replacements based on preg_replace_callback           |
 |                                                                       |
 +-----------------------------------------------------------------------+
 | Author: Thomas Bruederli <roundcube@gmail.com>                        |
 +-----------------------------------------------------------------------+

 $Id: rcube_string_replacer.php 5203 2011-09-12 06:44:56Z alec $

*/


/**
 * Helper class for string replacements based on preg_replace_callback
 *
 * @package Core
 */
class rcube_string_replacer
{
  public static $pattern = '/##str_replacement\[([0-9]+)\]##/';
  public $mailto_pattern;
  public $link_pattern;
  private $values = array();


  function __construct()
  {
    // Simplified domain expression for UTF8 characters handling
    // Support unicode/punycode in top-level domain part
    $utf_domain = '[^?&@"\'\\/()\s\r\t\n]+\\.([^\\x00-\\x2f\\x3b-\\x40\\x5b-\\x60\\x7b-\\x7f]{2,}|xn--[a-z0-9]{2,})';
    $url1 = '.:;,';
    $url2 = 'a-z0-9%=#@+?&\\/_~\\[\\]-';

    $this->link_pattern = "/([\w]+:\/\/|\Wwww\.)($utf_domain([$url1]?[$url2]+)*)/i";
    $this->mailto_pattern = "/("
        ."[-\w!\#\$%&\'*+~\/^`|{}=]+(?:\.[-\w!\#\$%&\'*+~\/^`|{}=]+)*"  // local-part
        ."@$utf_domain"                                                 // domain-part
        ."(\?[$url1$url2]+)?"                                           // e.g. ?subject=test...
        .")/i";
  }

  /**
   * Add a string to the internal list
   *
   * @param string String value 
   * @return int Index of value for retrieval
   */
  public function add($str)
  {
    $i = count($this->values);
    $this->values[$i] = $str;
    return $i;
  }

  /**
   * Build replacement string
   */
  public function get_replacement($i)
  {
    return '##str_replacement['.$i.']##';
  }

  /**
   * Callback function used to build HTML links around URL strings
   *
   * @param array Matches result from preg_replace_callback
   * @return int Index of saved string value
   */
  public function link_callback($matches)
  {
    $i = -1;
    $scheme = strtolower($matches[1]);

    if (preg_match('!^(http|ftp|file)s?://!', $scheme)) {
      $url = $matches[1] . $matches[2];
    }
    else if (preg_match('/^(\W)www\.$/', $matches[1], $m)) {
      $url        = 'www.' . $matches[2];
      $url_prefix = 'http://';
      $prefix     = $m[1];
    }

    if ($url) {
      $suffix = $this->parse_url_brackets($url);
      $i = $this->add($prefix . html::a(array(
          'href' => $url_prefix . $url,
          'target' => '_blank'
        ), Q($url)) . $suffix);
    }

    // Return valid link for recognized schemes, otherwise, return the unmodified string for unrecognized schemes.
    return $i >= 0 ? $this->get_replacement($i) : $matches[0];
  }

  /**
   * Callback function used to build mailto: links around e-mail strings
   *
   * @param array Matches result from preg_replace_callback
   * @return int Index of saved string value
   */
  public function mailto_callback($matches)
  {
    $href   = $matches[1];
    $suffix = $this->parse_url_brackets($href);

    $i = $this->add(html::a(array(
        'href' => 'mailto:' . $href,
        'onclick' => "return ".JS_OBJECT_NAME.".command('compose','".JQ($href)."',this)",
      ), Q($href)) . $suffix);

    return $i >= 0 ? $this->get_replacement($i) : '';
  }

  /**
   * Look up the index from the preg_replace matches array
   * and return the substitution value.
   *
   * @param array Matches result from preg_replace_callback
   * @return string Value at index $matches[1]
   */
  public function replace_callback($matches)
  {
    return $this->values[$matches[1]];
  }

  /**
   * Replace substituted strings with original values
   */
  public function resolve($str)
  {
    return preg_replace_callback(self::$pattern, array($this, 'replace_callback'), $str);
  }

  /**
   * Fixes bracket characters in URL handling
   */
  public static function parse_url_brackets(&$url)
  {
    // #1487672: special handling of square brackets,
    // URL regexp allows [] characters in URL, for example:
    // "http://example.com/?a[b]=c". However we need to handle
    // properly situation when a bracket is placed at the end
    // of the link e.g. "[http://example.com]"
    if (preg_match('/(\\[|\\])/', $url)) {
      $in = false;
      for ($i=0, $len=strlen($url); $i<$len; $i++) {
        if ($url[$i] == '[') {
          if ($in)
            break;
          $in = true;
        }
        else if ($url[$i] == ']') {
          if (!$in)
            break;
          $in = false;
        }
      }

      if ($i<$len) {
        $suffix = substr($url, $i);
        $url    = substr($url, 0, $i);
      }
    }

    return $suffix;
  }

}
