<?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

 * @subpackage Amazon

 * @license    http://framework.zend.com/license/new-bsd     New BSD License

 */

/**

 * @see Zend_Rest_Client

 */

require_once 'Zend/Rest/Client.php';

/**

 * @category   Zend

 * @package    Zend_Service

 * @subpackage Amazon

 * @license    http://framework.zend.com/license/new-bsd     New BSD License

 */

class Zend_Service_Amazon

{

    /**

     * Amazon Web Services Access Key ID

     *

     * @var string

     */

    public $appId;

    /**

     * @var string

     */

    protected $_secretKey = null;

    /**

     * @var string

     */

    protected $_baseUri = null;

    /**

     * List of Amazon Web Service base URLs, indexed by country code

     *

     * @var array

     */

    protected $_baseUriList = array('US' => 'http://webservices.amazon.com',

                                    'UK' => 'http://webservices.amazon.co.uk',

                                    'DE' => 'http://webservices.amazon.de',

                                    'JP' => 'http://webservices.amazon.co.jp',

                                    'FR' => 'http://webservices.amazon.fr',

                                    'CA' => 'http://webservices.amazon.ca');

    /**

     * Reference to REST client object

     *

     * @var Zend_Rest_Client

     */

    protected $_rest = null;

    /**

     * Constructs a new Amazon Web Services Client

     *

     * @param  string $appId       Developer's Amazon appid

     * @param  string $countryCode Country code for Amazon service; may be US, UK, DE, JP, FR, CA

     * @throws Zend_Service_Exception

     * @return Zend_Service_Amazon

     */

    public function __construct($appId, $countryCode = 'US', $secretKey = null)

    {

        $this->appId = (string) $appId;

        $this->_secretKey = $secretKey;

        $countryCode = (string) $countryCode;

        if (!isset($this->_baseUriList[$countryCode])) {

            /**

             * @see Zend_Service_Exception

             */

            require_once 'Zend/Service/Exception.php';

            throw new Zend_Service_Exception("Unknown country code: $countryCode");

        }

        $this->_baseUri = $this->_baseUriList[$countryCode];

    }

    /**

     * Search for Items

     *

     * @param  array $options Options to use for the Search Query

     * @throws Zend_Service_Exception

     * @return Zend_Service_Amazon_ResultSet

     */

    public function itemSearch(array $options)

    {

        $client = $this->getRestClient();

        $client->setUri($this->_baseUri);

        $defaultOptions = array('ResponseGroup' => 'Small');

        $options = $this->_prepareOptions('ItemSearch', $options, $defaultOptions);

        $client->getHttpClient()->resetParameters();

        $response = $client->restGet('/onca/xml', $options);

        if ($response->isError()) {

            /**

             * @see Zend_Service_Exception

             */

            require_once 'Zend/Service/Exception.php';

            throw new Zend_Service_Exception('An error occurred sending request. Status code: '

                                           . $response->getStatus());

        }

        $dom = new DOMDocument();

        $dom->loadXML($response->getBody());

        self::_checkErrors($dom);

        /**

         * @see Zend_Service_Amazon_ResultSet

         */

        require_once 'Zend/Service/Amazon/ResultSet.php';

        return new Zend_Service_Amazon_ResultSet($dom);

    }

    /**

     * Look up item(s) by ASIN

     *

     * @param  string $asin    Amazon ASIN ID

     * @param  array  $options Query Options

     * @throws Zend_Service_Exception

     * @return Zend_Service_Amazon_Item|Zend_Service_Amazon_ResultSet

     */

    public function itemLookup($asin, array $options = array())

    {

        $client = $this->getRestClient();

        $client->setUri($this->_baseUri);

        $client->getHttpClient()->resetParameters();

        $defaultOptions = array('ResponseGroup' => 'Small');

        $options['ItemId'] = (string) $asin;

        $options = $this->_prepareOptions('ItemLookup', $options, $defaultOptions);

        $response = $client->restGet('/onca/xml', $options);

        if ($response->isError()) {

            /**

             * @see Zend_Service_Exception

             */

            require_once 'Zend/Service/Exception.php';

            throw new Zend_Service_Exception(

                'An error occurred sending request. Status code: ' . $response->getStatus()

            );

        }

        $dom = new DOMDocument();

        $dom->loadXML($response->getBody());

        self::_checkErrors($dom);

        $xpath = new DOMXPath($dom);

        $items = $xpath->query('//az:Items/az:Item');

        if ($items->length == 1) {

            /**

             * @see Zend_Service_Amazon_Item

             */

            require_once 'Zend/Service/Amazon/Item.php';

            return new Zend_Service_Amazon_Item($items->item(0));

        }

        /**

         * @see Zend_Service_Amazon_ResultSet

         */

        require_once 'Zend/Service/Amazon/ResultSet.php';

        return new Zend_Service_Amazon_ResultSet($dom);

    }

    /**

     * Returns a reference to the REST client

     *

     * @return Zend_Rest_Client

     */

    public function getRestClient()

    {

        if($this->_rest === null) {

            $this->_rest = new Zend_Rest_Client();

        }

        return $this->_rest;

    }

    /**

     * Set REST client

     *

     * @param Zend_Rest_Client

     * @return Zend_Service_Amazon

     */

    public function setRestClient(Zend_Rest_Client $client)

    {

        $this->_rest = $client;

        return $this;

    }

    /**

     * Prepare options for request

     *

     * @param  string $query          Action to perform

     * @param  array  $options        User supplied options

     * @param  array  $defaultOptions Default options

     * @return array

     */

    protected function _prepareOptions($query, array $options, array $defaultOptions)

    {

        $options['AWSAccessKeyId'] = $this->appId;

        $options['Service']        = 'AWSECommerceService';

        $options['Operation']      = (string) $query;

        // de-canonicalize out sort key

        if (isset($options['ResponseGroup'])) {

            $responseGroup = explode(',', $options['ResponseGroup']);

            if (!in_array('Request', $responseGroup)) {

                $responseGroup[] = 'Request';

                $options['ResponseGroup'] = implode(',', $responseGroup);

            }

        }

        $options = array_merge($defaultOptions, $options);

        if($this->_secretKey !== null) {

            $options['Timestamp'] = gmdate("Y-m-d\TH:i:s\Z");;

            ksort($options);

            $options['Signature'] = self::computeSignature($this->_baseUri, $this->_secretKey, $options);

        }

        return $options;

    }

    /**

     * Compute Signature for Authentication with Amazon Product Advertising Webservices

     *

     * @param  string $baseUri

     * @param  string $secretKey

     * @param  array $options

     * @return string

     */

    static public function computeSignature($baseUri, $secretKey, array $options)

    {

        require_once "Zend/Crypt/Hmac.php";

        $signature = self::buildRawSignature($baseUri, $options);

        return base64_encode(

            Zend_Crypt_Hmac::compute($secretKey, 'sha256', $signature, Zend_Crypt_Hmac::BINARY)

        );

    }

    /**

     * Build the Raw Signature Text

     *

     * @param  string $baseUri

     * @param  array $options

     * @return string

     */

    static public function buildRawSignature($baseUri, $options)

    {

        ksort($options);

        $params = array();

        foreach($options AS $k => $v) {

            $params[] = $k."=".rawurlencode($v);

        }

        return sprintf("GET\n%s\n/onca/xml\n%s",

            str_replace('http://', '', $baseUri),

            implode("&", $params)

        );

    }

    /**

     * Check result for errors

     *

     * @param  DOMDocument $dom

     * @throws Zend_Service_Exception

     * @return void

     */

    protected static function _checkErrors(DOMDocument $dom)

    {

        $xpath = new DOMXPath($dom);

        if ($xpath->query('//az:Error')->length >= 1) {

            $code = $xpath->query('//az:Error/az:Code/text()')->item(0)->data;

            $message = $xpath->query('//az:Error/az:Message/text()')->item(0)->data;

            switch($code) {

                case 'AWS.ECommerceService.NoExactMatches':

                    break;

                default:

                    /**

                     * @see Zend_Service_Exception

                     */

                    require_once 'Zend/Service/Exception.php';

                    throw new Zend_Service_Exception("$message ($code)");

            }

        }

    }

}