<?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.
 */

//@require 'Swift/KeyCache.php';
//@require 'Swift/KeyCacheInputStream.php';
//@require 'Swift/InputByteStream.php';
//@require 'Swift/OutputByteStrean.php';
//@require 'Swift/SwiftException.php';

/**
 * A basic KeyCache backed by an array.
 * @package Swift
 * @subpackage KeyCache
 * @author Chris Corbyn
 */
class Swift_KeyCache_ArrayKeyCache implements Swift_KeyCache
{

  /**
   * Cache contents.
   * @var array
   * @access private
   */
  private $_contents = array();

  /**
   * An InputStream for cloning.
   * @var Swift_KeyCache_KeyCacheInputStream
   * @access private
   */
  private $_stream;

  /**
   * Create a new ArrayKeyCache with the given $stream for cloning to make
   * InputByteStreams.
   * @param Swift_KeyCache_KeyCacheInputStream $stream
   */
  public function __construct(Swift_KeyCache_KeyCacheInputStream $stream)
  {
    $this->_stream = $stream;
  }

  /**
   * Set a string into the cache under $itemKey for the namespace $nsKey.
   * @param string $nsKey
   * @param string $itemKey
   * @param string $string
   * @param int $mode
   * @see MODE_WRITE, MODE_APPEND
   */
  public function setString($nsKey, $itemKey, $string, $mode)
  {
    $this->_prepareCache($nsKey);
    switch ($mode)
    {
      case self::MODE_WRITE:
        $this->_contents[$nsKey][$itemKey] = $string;
        break;
      case self::MODE_APPEND:
        if (!$this->hasKey($nsKey, $itemKey))
        {
          $this->_contents[$nsKey][$itemKey] = '';
        }
        $this->_contents[$nsKey][$itemKey] .= $string;
        break;
      default:
        throw new Swift_SwiftException(
          'Invalid mode [' . $mode . '] used to set nsKey='.
          $nsKey . ', itemKey=' . $itemKey
          );
    }
  }

  /**
   * Set a ByteStream into the cache under $itemKey for the namespace $nsKey.
   * @param string $nsKey
   * @param string $itemKey
   * @param Swift_OutputByteStream $os
   * @param int $mode
   * @see MODE_WRITE, MODE_APPEND
   */
  public function importFromByteStream($nsKey, $itemKey, Swift_OutputByteStream $os,
    $mode)
  {
    $this->_prepareCache($nsKey);
    switch ($mode)
    {
      case self::MODE_WRITE:
        $this->clearKey($nsKey, $itemKey);
      case self::MODE_APPEND:
        if (!$this->hasKey($nsKey, $itemKey))
        {
          $this->_contents[$nsKey][$itemKey] = '';
        }
        while (false !== $bytes = $os->read(8192))
        {
          $this->_contents[$nsKey][$itemKey] .= $bytes;
        }
        break;
      default:
        throw new Swift_SwiftException(
          'Invalid mode [' . $mode . '] used to set nsKey='.
          $nsKey . ', itemKey=' . $itemKey
          );
    }
  }

  /**
   * Provides a ByteStream which when written to, writes data to $itemKey.
   * NOTE: The stream will always write in append mode.
   * @param string $nsKey
   * @param string $itemKey
   * @return Swift_InputByteStream
   */
  public function getInputByteStream($nsKey, $itemKey,
    Swift_InputByteStream $writeThrough = null)
  {
    $is = clone $this->_stream;
    $is->setKeyCache($this);
    $is->setNsKey($nsKey);
    $is->setItemKey($itemKey);
    if (isset($writeThrough))
    {
      $is->setWriteThroughStream($writeThrough);
    }
    return $is;
  }

  /**
   * Get data back out of the cache as a string.
   * @param string $nsKey
   * @param string $itemKey
   * @return string
   */
  public function getString($nsKey, $itemKey)
  {
    $this->_prepareCache($nsKey);
    if ($this->hasKey($nsKey, $itemKey))
    {
      return $this->_contents[$nsKey][$itemKey];
    }
  }

  /**
   * Get data back out of the cache as a ByteStream.
   * @param string $nsKey
   * @param string $itemKey
   * @param Swift_InputByteStream $is to write the data to
   */
  public function exportToByteStream($nsKey, $itemKey, Swift_InputByteStream $is)
  {
    $this->_prepareCache($nsKey);
    $is->write($this->getString($nsKey, $itemKey));
  }

  /**
   * Check if the given $itemKey exists in the namespace $nsKey.
   * @param string $nsKey
   * @param string $itemKey
   * @return boolean
   */
  public function hasKey($nsKey, $itemKey)
  {
    $this->_prepareCache($nsKey);
    return array_key_exists($itemKey, $this->_contents[$nsKey]);
  }

  /**
   * Clear data for $itemKey in the namespace $nsKey if it exists.
   * @param string $nsKey
   * @param string $itemKey
   */
  public function clearKey($nsKey, $itemKey)
  {
    unset($this->_contents[$nsKey][$itemKey]);
  }

  /**
   * Clear all data in the namespace $nsKey if it exists.
   * @param string $nsKey
   */
  public function clearAll($nsKey)
  {
    unset($this->_contents[$nsKey]);
  }

  // -- Private methods

  /**
   * Initialize the namespace of $nsKey if needed.
   * @param string $nsKey
   * @access private
   */
  private function _prepareCache($nsKey)
  {
    if (!array_key_exists($nsKey, $this->_contents))
    {
      $this->_contents[$nsKey] = array();
    }
  }

}
