<?php

/**

 * 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_Cloud

 * @subpackage DocumentService

 * @copyright  Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)

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

 */

require_once 'Zend/Cloud/DocumentService/QueryAdapter.php';

/**

 * Generic query object

 *

 * Aggregates operations in an array of clauses, where the first element 

 * describes the clause type, and the next element describes the criteria.

 *

 * @category   Zend

 * @package    Zend_Cloud

 * @subpackage DocumentService

 * @copyright  Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)

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

 */

class Zend_Cloud_DocumentService_Query

    implements Zend_Cloud_DocumentService_QueryAdapter

{

    /**

     * Known query types

     */

    const QUERY_SELECT  = 'select';

    const QUERY_FROM    = 'from';

    const QUERY_WHERE   = 'where';

    const QUERY_WHEREID = 'whereid'; // request element by ID

    const QUERY_LIMIT   = 'limit';

    const QUERY_ORDER   = 'order';

    /**

     * Clause list

     * 

     * @var array

     */

    protected $_clauses = array();

    /**

     * Generic clause

     * 

     * You can use any clause by doing $query->foo('bar')

     * but concrete adapters should be able to recognise it

     * 

     * The call will be iterpreted as clause 'foo' with argument 'bar' 

     * 

     * @param  string $name Clause/method name

     * @param  mixed $args

     * @return Zend_Cloud_DocumentService_Query

     */

    public function __call($name, $args) 

    {

        $this->_clauses[] = array(strtolower($name), $args);

        return $this;

    }

    /**

     * SELECT clause (fields to be selected)

     * 

     * @param  null|string|array $select 

     * @return Zend_Cloud_DocumentService_Query

     */

    public function select($select)

    {

        if (empty($select)) {

            return $this;

        }

        if (!is_string($select) && !is_array($select)) {

            require_once 'Zend/Cloud/DocumentService/Exception.php';           

            throw new Zend_Cloud_DocumentService_Exception("SELECT argument must be a string or an array of strings");

        }

        $this->_clauses[] = array(self::QUERY_SELECT, $select);

        return $this;

    }

    /**

     * FROM clause

     * 

     * @param string $name Field names  

     * @return Zend_Cloud_DocumentService_Query

     */

    public function from($name)

    {

        if(!is_string($name)) {

            require_once 'Zend/Cloud/DocumentService/Exception.php';           

            throw new Zend_Cloud_DocumentService_Exception("FROM argument must be a string");

        }

        $this->_clauses[] = array(self::QUERY_FROM, $name);

        return $this;

    }

    /**

     * WHERE query

     * 

     * @param string $cond Condition

     * @param array $args Arguments to substitute instead of ?'s in condition

     * @param string $op relation to other clauses - and/or

     * @return Zend_Cloud_DocumentService_Query

     */

    public function where($cond, $value = null, $op = 'and')

    {

        if (!is_string($cond)) {

            require_once 'Zend/Cloud/DocumentService/Exception.php';           

            throw new Zend_Cloud_DocumentService_Exception("WHERE argument must be a string");

        }

        $this->_clauses[] = array(self::QUERY_WHERE, array($cond, $value, $op));

        return $this;

    }

    /**

     * Select record or fields by ID

     * 

     * @param  string|int $value Identifier to select by

     * @return Zend_Cloud_DocumentService_Query

     */

    public function whereId($value)

    {

        if (!is_scalar($value)) {

            require_once 'Zend/Cloud/DocumentService/Exception.php';           

            throw new Zend_Cloud_DocumentService_Exception("WHEREID argument must be a scalar");

        }

        $this->_clauses[] = array(self::QUERY_WHEREID, $value);

        return $this;

    }

    /**

     * LIMIT clause (how many items to return)

     * 

     * @param  int $limit 

     * @return Zend_Cloud_DocumentService_Query

     */

    public function limit($limit)

    {

        if ($limit != (int) $limit) {

            require_once 'Zend/Cloud/DocumentService/Exception.php';           

            throw new Zend_Cloud_DocumentService_Exception("LIMIT argument must be an integer");

        }

        $this->_clauses[] = array(self::QUERY_LIMIT, $limit);

        return $this;

    }

    /**

     * ORDER clause; field or fields to sort by, and direction to sort

     * 

     * @param  string|int|array $sort 

     * @param  string $direction 

     * @return Zend_Cloud_DocumentService_Query

     */

    public function order($sort, $direction = 'asc')

    {

        $this->_clauses[] = array(self::QUERY_ORDER, array($sort, $direction));

        return $this;

    }

    /**

     * "Assemble" the query

     *

     * Simply returns the clauses present.

     * 

     * @return array

     */

    public function assemble()

    {

        return $this->getClauses();

    }

    /**

     * Return query clauses as an array

     * 

     * @return array Clauses in the query

     */

    public function getClauses()

    {

         return $this->_clauses;   

    }

}