<?php

/*

 * This file is part of SwiftMailer.

 * (c) 2004-2009 Chris Corbyn

 *

 * For the full copyright and license information, please view the LICENSE

 * file that was distributed with this source code.

 */

/**

 * An abstract base MIME Header.

 * @package Swift

 * @subpackage Mime

 * @author Chris Corbyn

 */

abstract class Swift_Mime_Headers_AbstractHeader implements Swift_Mime_Header

{

  /**

   * The name of this Header.

   * @var string

   * @access private

   */

  private $_name;

  /**

   * The Grammar used for this Header.

   * @var Swift_Mime_Grammar

   * @access private

   */

  private $_grammar;

  /**

   * The Encoder used to encode this Header.

   * @var Swift_Encoder

   * @access private

   */

  private $_encoder;

  /**

   * The maximum length of a line in the header.

   * @var int

   * @access private

   */

  private $_lineLength = 78;

  /**

   * The language used in this Header.

   * @var string

   */

  private $_lang;

  /**

   * The character set of the text in this Header.

   * @var string

   * @access private

   */

  private $_charset = 'utf-8';

  /**

   * The value of this Header, cached.

   * @var string

   * @access private

   */

  private $_cachedValue = null;

  /**

   * Creates a new Header.

   * @param Swift_Mime_Grammar $grammar

   */ 

  public function __construct(Swift_Mime_Grammar $grammar)

  {

    $this->setGrammar($grammar);

  }

  /**

   * Set the character set used in this Header.

   * @param string $charset

   */

  public function setCharset($charset)

  {

    $this->clearCachedValueIf($charset != $this->_charset);

    $this->_charset = $charset;

    if (isset($this->_encoder))

    {

      $this->_encoder->charsetChanged($charset);

    }

  }

  /**

   * Get the character set used in this Header.

   * @return string

   */

  public function getCharset()

  {

    return $this->_charset;

  }

  /**

   * Set the language used in this Header.

   * For example, for US English, 'en-us'.

   * This can be unspecified.

   * @param string $lang

   */

  public function setLanguage($lang)

  {

    $this->clearCachedValueIf($this->_lang != $lang);

    $this->_lang = $lang;

  }

  /**

   * Get the language used in this Header.

   * @return string

   */

  public function getLanguage()

  {

    return $this->_lang;

  }

  /**

   * Set the encoder used for encoding the header.

   * @param Swift_Mime_HeaderEncoder $encoder

   */

  public function setEncoder(Swift_Mime_HeaderEncoder $encoder)

  {

    $this->_encoder = $encoder;

    $this->setCachedValue(null);

  }

  /**

   * Get the encoder used for encoding this Header.

   * @return Swift_Mime_HeaderEncoder

   */

  public function getEncoder()

  {

    return $this->_encoder;

  }

  /**

   * Set the grammar used for the header.

   * @param Swift_Mime_Grammar $grammar

   */

  public function setGrammar(Swift_Mime_Grammar $grammar)

  {

    $this->_grammar = $grammar;

    $this->setCachedValue(null);

  }

  /**

   * Get the grammar used for this Header.

   * @return Swift_Mime_Grammar

   */

  public function getGrammar()

  {

    return $this->_grammar;

  }

  /**

   * Get the name of this header (e.g. charset).

   * @return string

   */

  public function getFieldName()

  {

    return $this->_name;

  }

  /**

   * Set the maximum length of lines in the header (excluding EOL).

   * @param int $lineLength

   */

  public function setMaxLineLength($lineLength)

  {

    $this->clearCachedValueIf($this->_lineLength != $lineLength);

    $this->_lineLength = $lineLength;

  }

  /**

   * Get the maximum permitted length of lines in this Header.

   * @return int

   */

  public function getMaxLineLength()

  {

    return $this->_lineLength;

  }

  /**

   * Get this Header rendered as a RFC 2822 compliant string.

   * @return string

   * @throws Swift_RfcComplianceException

   */

  public function toString()

  {

    return $this->_tokensToString($this->toTokens());

  }

  /**

   * Returns a string representation of this object.

   *

   * @return string

   *

   * @see toString()

   */

  public function __toString()

  {

    return $this->toString();

  }

  // -- Points of extension

  /**

   * Set the name of this Header field.

   * @param string $name

   * @access protected

   */

  protected function setFieldName($name)

  {

    $this->_name = $name;

  }

  /**

   * Produces a compliant, formatted RFC 2822 'phrase' based on the string given.

   * @param Swift_Mime_Header $header

   * @param string $string as displayed

   * @param string $charset of the text

   * @param Swift_Mime_HeaderEncoder $encoder

   * @param boolean $shorten the first line to make remove for header name

   * @return string

   */

  protected function createPhrase(Swift_Mime_Header $header, $string, $charset,

    Swift_Mime_HeaderEncoder $encoder = null, $shorten = false)

  {

    //Treat token as exactly what was given

    $phraseStr = $string;

    //If it's not valid

    if (!preg_match('/^' . $this->getGrammar()->getDefinition('phrase') . '$/D', $phraseStr))

    {

      // .. but it is just ascii text, try escaping some characters

      // and make it a quoted-string

      if (preg_match('/^' . $this->getGrammar()->getDefinition('text') . '*$/D', $phraseStr))

      {

        $phraseStr = $this->getGrammar()->escapeSpecials(

          $phraseStr, array('"'), $this->getGrammar()->getSpecials()

          );

        $phraseStr = '"' . $phraseStr . '"';

      }

      else // ... otherwise it needs encoding

      {

        //Determine space remaining on line if first line

        if ($shorten)

        {

          $usedLength = strlen($header->getFieldName() . ': ');

        }

        else

        {

          $usedLength = 0;

        }

        $phraseStr = $this->encodeWords($header, $string, $usedLength);

      }

    }

    return $phraseStr;

  }

  /**

   * Encode needed word tokens within a string of input.

   * @param string $input

   * @param string $usedLength, optional

   * @return string

   */

  protected function encodeWords(Swift_Mime_Header $header, $input,

    $usedLength = -1)

  {

    $value = '';

    $tokens = $this->getEncodableWordTokens($input);

    foreach ($tokens as $token)

    {

      //See RFC 2822, Sect 2.2 (really 2.2 ??)

      if ($this->tokenNeedsEncoding($token))

      {

        //Don't encode starting WSP

        $firstChar = substr($token, 0, 1);

        switch($firstChar)

        {

          case ' ':

          case "\t":

            $value .= $firstChar;

            $token = substr($token, 1);

        }

        if (-1 == $usedLength)

        {

          $usedLength = strlen($header->getFieldName() . ': ') + strlen($value);

        }

        $value .= $this->getTokenAsEncodedWord($token, $usedLength);

        $header->setMaxLineLength(76); //Forefully override

      }

      else

      {

        $value .= $token;

      }

    }

    return $value;

  }

  /**

   * Test if a token needs to be encoded or not.

   * @param string $token

   * @return boolean

   */

  protected function tokenNeedsEncoding($token)

  {

    return preg_match('~[\x00-\x08\x10-\x19\x7F-\xFF\r\n]~', $token);

  }

  /**

   * Splits a string into tokens in blocks of words which can be encoded quickly.

   * @param string $string

   * @return string[]

   */

  protected function getEncodableWordTokens($string)

  {

    $tokens = array();

    $encodedToken = '';

    //Split at all whitespace boundaries

    foreach (preg_split('~(?=[\t ])~', $string) as $token)

    {

      if ($this->tokenNeedsEncoding($token))

      {

        $encodedToken .= $token;

      }

      else

      {

        if (strlen($encodedToken) > 0)

        {

          $tokens[] = $encodedToken;

          $encodedToken = '';

        }

        $tokens[] = $token;

      }

    }

    if (strlen($encodedToken))

    {

      $tokens[] = $encodedToken;

    }

    return $tokens;

  }

  /**

   * Get a token as an encoded word for safe insertion into headers.

   * @param string $token to encode

   * @param int $firstLineOffset, optional

   * @return string

   */

  protected function getTokenAsEncodedWord($token, $firstLineOffset = 0)

  {

    //Adjust $firstLineOffset to account for space needed for syntax

    $charsetDecl = $this->_charset;

    if (isset($this->_lang))

    {

      $charsetDecl .= '*' . $this->_lang;

    }

    $encodingWrapperLength = strlen(

      '=?' . $charsetDecl . '?' . $this->_encoder->getName() . '??='

      );

    if ($firstLineOffset >= 75) //Does this logic need to be here?

    {

      $firstLineOffset = 0;

    }

    $encodedTextLines = explode("\r\n",

      $this->_encoder->encodeString(

        $token, $firstLineOffset, 75 - $encodingWrapperLength

        )

      );

    foreach ($encodedTextLines as $lineNum => $line)

    {

      $encodedTextLines[$lineNum] = '=?' . $charsetDecl .

        '?' . $this->_encoder->getName() .

        '?' . $line . '?=';

    }

    return implode("\r\n ", $encodedTextLines);

  }

  /**

   * Generates tokens from the given string which include CRLF as individual tokens.

   * @param string $token

   * @return string[]

   * @access protected

   */

  protected function generateTokenLines($token)

  {

    return preg_split('~(\r\n)~', $token, -1, PREG_SPLIT_DELIM_CAPTURE);

  }

  /**

   * Set a value into the cache.

   * @param string $value

   * @access protected

   */

  protected function setCachedValue($value)

  {

    $this->_cachedValue = $value;

  }

  /**

   * Get the value in the cache.

   * @return string

   * @access protected

   */

  protected function getCachedValue()

  {

    return $this->_cachedValue;

  }

  /**

   * Clear the cached value if $condition is met.

   * @param boolean $condition

   * @access protected

   */

  protected function clearCachedValueIf($condition)

  {

    if ($condition)

    {

      $this->setCachedValue(null);

    }

  }

  // -- Private methods

  /**

   * Generate a list of all tokens in the final header.

   * @param string $string input, optional

   * @return string[]

   * @access private

   */

  protected function toTokens($string = null)

  {

    if (is_null($string))

    {

      $string = $this->getFieldBody();

    }

    $tokens = array();

    //Generate atoms; split at all invisible boundaries followed by WSP

    foreach (preg_split('~(?=[ \t])~', $string) as $token)