<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Service_Amazon
 * @subpackage Authentication
 * @copyright  Copyright (c) 2005-2011 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */

/**
 * @see Zend_Service_Amazon_Authentication
 */
require_once 'Zend/Service/Amazon/Authentication.php';

/**
 * @see Zend_Crypt_Hmac
 */
require_once 'Zend/Crypt/Hmac.php';

/**
 * @category   Zend
 * @package    Zend_Service_Amazon
 * @subpackage Authentication
 * @copyright  Copyright (c) 2005-2011 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_Service_Amazon_Authentication_V2 extends Zend_Service_Amazon_Authentication
{
    /**
     * Signature Version
     */
    protected $_signatureVersion = '2';

    /**
     * Signature Encoding Method
     */
    protected $_signatureMethod = 'HmacSHA256';

    /**
     * Type of http request
     * @var string
     */
    protected $_httpMethod = "POST";

    /**
     * Generate the required attributes for the signature
     * @param string $url
     * @param array $parameters
     * @return string
     */
    public function generateSignature($url, array &$parameters)
    {
        $parameters['AWSAccessKeyId']   = $this->_accessKey;
        $parameters['SignatureVersion'] = $this->_signatureVersion;
        $parameters['Version']          = $this->_apiVersion;
        $parameters['SignatureMethod']  = $this->_signatureMethod;
        if(!isset($parameters['Timestamp'])) {
            $parameters['Timestamp']    = gmdate('Y-m-d\TH:i:s\Z', time()+10);
        }

        $data = $this->_signParameters($url, $parameters);

        return $data;
    }

    /**
     * Set http request type to POST or GET
     * @param string $method
     */
    public function setHttpMethod($method = "POST") {
        $this->_httpMethod = strtoupper($method);
    }

    /**
     * Get the current http request type
     * @return string
     */
    public function getHttpMethod()
    {
        return $this->_httpMethod;
    }

    /**
     * Computes the RFC 2104-compliant HMAC signature for request parameters
     *
     * This implements the Amazon Web Services signature, as per the following
     * specification:
     *
     * 1. Sort all request parameters (including <tt>SignatureVersion</tt> and
     *    excluding <tt>Signature</tt>, the value of which is being created),
     *    ignoring case.
     *
     * 2. Iterate over the sorted list and append the parameter name (in its
     *    original case) and then its value. Do not URL-encode the parameter
     *    values before constructing this string. Do not use any separator
     *    characters when appending strings.
     *
     * @param  string $queue_url  Queue URL
     * @param  array  $parameters the parameters for which to get the signature.
     *
     * @return string the signed data.
     */
    protected function _signParameters($url, array &$paramaters)
    {
        $data = $this->_httpMethod . "\n";
        $data .= parse_url($url, PHP_URL_HOST) . "\n";
        $data .= ('' == $path = parse_url($url, PHP_URL_PATH)) ? '/' : $path;
        $data .= "\n";

        uksort($paramaters, 'strcmp');
        unset($paramaters['Signature']);

        $arrData = array();
        foreach($paramaters as $key => $value) {
            $arrData[] = $key . '=' . str_replace('%7E', '~', rawurlencode($value));
        }

        $data .= implode('&', $arrData);

        $hmac = Zend_Crypt_Hmac::compute($this->_secretKey, 'SHA256', $data, Zend_Crypt_Hmac::BINARY);

        $paramaters['Signature'] = base64_encode($hmac);

        return $data;
    }
}