<?php
  
  namespace Sabre\VObject;
  
  /**
   * VCALENDAR/VCARD reader
   *
   * This class reads the vobject file, and returns a full element tree.
   *
   * TODO: this class currently completely works 'statically'. This is pointless,
   * and defeats OOP principals. Needs refactoring in a future version.
   *

   * @copyright Copyright (C) 2007-2013 fruux GmbH (https://fruux.com/).
   * @author Evert Pot (http://evertpot.com/)

   * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License
   */
  class Reader {
  
      /**
       * If this option is passed to the reader, it will be less strict about the
       * validity of the lines.
       *
       * Currently using this option just means, that it will accept underscores
       * in property names.
       */
      const OPTION_FORGIVING = 1;
  
      /**
       * If this option is turned on, any lines we cannot parse will be ignored
       * by the reader.
       */
      const OPTION_IGNORE_INVALID_LINES = 2;
  
      /**
       * Parses the file and returns the top component
       *
       * The options argument is a bitfield. Pass any of the OPTIONS constant to
       * alter the parsers' behaviour.
       *
       * @param string $data
       * @param int $options
       * @return Node
       */
      static function read($data, $options = 0) {
  
          // Normalizing newlines
          $data = str_replace(array("\r","
  
  "), array("
  ","
  "), $data);
  
          $lines = explode("
  ", $data);
  
          // Unfolding lines
          $lines2 = array();
          foreach($lines as $line) {
  
              // Skipping empty lines
              if (!$line) continue;
  
              if ($line[0]===" " || $line[0]==="\t") {
                  $lines2[count($lines2)-1].=substr($line,1);
              } else {
                  $lines2[] = $line;
              }
  
          }
  
          unset($lines);
  
          reset($lines2);
  
          return self::readLine($lines2, $options);
  
      }
  
      /**
       * Reads and parses a single line.
       *
       * This method receives the full array of lines. The array pointer is used
       * to traverse.
       *
       * This method returns null if an invalid line was encountered, and the
       * IGNORE_INVALID_LINES option was turned on.
       *
       * @param array $lines
       * @param int $options See the OPTIONS constants.
       * @return Node
       */
      static private function readLine(&$lines, $options = 0) {
  
          $line = current($lines);
          $lineNr = key($lines);
          next($lines);
  
          // Components
          if (strtoupper(substr($line,0,6)) === "BEGIN:") {
  
              $componentName = strtoupper(substr($line,6));
              $obj = Component::create($componentName);
  
              $nextLine = current($lines);
  
              while(strtoupper(substr($nextLine,0,4))!=="END:") {
  
                  $parsedLine = self::readLine($lines, $options);
                  $nextLine = current($lines);
  
                  if (is_null($parsedLine)) {
                      continue;
                  }
                  $obj->add($parsedLine);
  
                  if ($nextLine===false)
                      throw new ParseException('Invalid VObject. Document ended prematurely.');
  
              }
  
              // Checking component name of the 'END:' line.
              if (substr($nextLine,4)!==$obj->name) {
                  throw new ParseException('Invalid VObject, expected: "END:' . $obj->name . '" got: "' . $nextLine . '"');
              }
              next($lines);
  
              return $obj;
  
          }
  
          // Properties
          //$result = preg_match('/(?P<name>[A-Z0-9-]+)(?:;(?P<parameters>^(?<!:):))(.*)$/',$line,$matches);
  
          if ($options & self::OPTION_FORGIVING) {
              $token = '[A-Z0-9-\._]+';
          } else {
              $token = '[A-Z0-9-\.]+';
          }
          $parameters = "(?:;(?P<parameters>([^:^\"]|\"([^\"]*)\")*))?";
          $regex = "/^(?P<name>$token)$parameters:(?P<value>.*)$/i";
  
          $result = preg_match($regex,$line,$matches);
  
          if (!$result) {
              if ($options & self::OPTION_IGNORE_INVALID_LINES) {
                  return null;
              } else {
                  throw new ParseException('Invalid VObject, line ' . ($lineNr+1) . ' did not follow the icalendar/vcard format');
              }
          }
  
          $propertyName = strtoupper($matches['name']);
          $propertyValue = preg_replace_callback('#(\\\\(\\\\|N|n))#',function($matches) {
              if ($matches[2]==='n' || $matches[2]==='N') {
                  return "
  ";
              } else {
                  return $matches[2];
              }
          }, $matches['value']);
  
          $obj = Property::create($propertyName, $propertyValue);
  
          if ($matches['parameters']) {
  
              foreach(self::readParameters($matches['parameters']) as $param) {
                  $obj->add($param);
              }
  
          }
  
          return $obj;
  
  
      }
  
      /**
       * Reads a parameter list from a property
       *
       * This method returns an array of Parameter
       *
       * @param string $parameters
       * @return array
       */
      static private function readParameters($parameters) {
  
          $token = '[A-Z0-9-]+';
  
          $paramValue = '(?P<paramValue>[^\"^;]*|"[^"]*")';
  
          $regex = "/(?<=^|;)(?P<paramName>$token)(=$paramValue(?=$|;))?/i";
          preg_match_all($regex, $parameters, $matches,  PREG_SET_ORDER);
  
          $params = array();
          foreach($matches as $match) {

              if (!isset($match['paramValue'])) {
  
                  $value = null;

              } else {

                  $value = $match['paramValue'];
  
                  if (isset($value[0]) && $value[0]==='"') {
                      // Stripping quotes, if needed
                      $value = substr($value,1,strlen($value)-2);

                  }

  
                  $value = preg_replace_callback('#(\\\\(\\\\|N|n|;|,))#',function($matches) {
                      if ($matches[2]==='n' || $matches[2]==='N') {
                          return "
  ";
                      } else {
                          return $matches[2];
                      }
                  }, $value);
  
              }

  
              $params[] = new Parameter($match['paramName'], $value);
  
          }
  
          return $params;
  
      }
  
  
  }