<?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_Search_Lucene
 * @subpackage Search
 * @copyright  Copyright (c) 2006 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */


/**
 * @category   Zend
 * @package    Zend_Search_Lucene
 * @subpackage Search
 * @copyright  Copyright (c) 2006 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
abstract class Zend_Search_Lucene_Search_Query
{

    /**
     * query boost factor
     *
     * @var float
     */
    private $_boost = 1;

    /**
     * Query weight
     *
     * @var Zend_Search_Lucene_Search_Weight
     */
    protected $_weight = null;


    /**
     * Gets the boost for this clause.  Documents matching
     * this clause will (in addition to the normal weightings) have their score
     * multiplied by boost.   The boost is 1.0 by default.
     *
     * @return float
     */
    public function getBoost()
    {
        return $this->_boost;
    }

    /**
     * Sets the boost for this query clause to $boost.
     *
     * @param float $boost
     */
    public function setBoost($boost)
    {
        $this->_boost = $boost;
    }

    /**
     * Score specified document
     *
     * @param integer $docId
     * @param Zend_Search_Lucene $reader
     * @return float
     */
    abstract public function score($docId, $reader);

    /**
     * Constructs an appropriate Weight implementation for this query.
     *
     * @param Zend_Search_Lucene $reader
     * @return Zend_Search_Lucene_Search_Weight
     */
    abstract public function createWeight($reader);

    /**
     * Constructs an initializes a Weight for a _top-level_query_.
     *
     * @param Zend_Search_Lucene $reader
     */
    protected function _initWeight($reader)
    {
        // Check, that it's a top-level query and query weight is not initialized yet.
        if ($this->_weight !== null) {
            return $this->_weight;
        }

        $this->createWeight($reader);
        $sum = $this->_weight->sumOfSquaredWeights();
        $queryNorm = $reader->getSimilarity()->queryNorm($sum);
        $this->_weight->normalize($queryNorm);
    }

    /**
     * Bind query to the index
     *
     * @param Zend_Search_Lucene $index
     * @return Zend_Search_Lucene_Search_Query
     */
    abstract public function rewrite(Zend_Search_Lucene $index);

    /**
     * Optimize query
     *
     * Do nothing by default
     *
     * @param Zend_Search_Lucene $index
     * @return Zend_Search_Lucene_Search_Query
     */
    public function optimize(Zend_Search_Lucene $index)
    {
        return $this;
    }

    /**
     * Reset query, so it can be reused within other queries or
     * with other indeces
     */
    public function reset()
    {
        $this->_weight = null;
    }


    /**
     * Print a query
     *
     * @return string
     */
    abstract public function __toString();
}

