<?php
/*
 *  $Id$
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * This software consists of voluntary contributions made by many individuals
 * and is licensed under the LGPL. For more information, see
 * <http://www.doctrine-project.org>.
 */

namespace Doctrine\ORM;

use Doctrine\ORM\Query\Parser,
    Doctrine\ORM\Query\QueryException;

/**
 * A Query object represents a DQL query.
 *
 * @license     http://www.opensource.org/licenses/lgpl-license.php LGPL
 * @link        www.doctrine-project.org
 * @since       1.0
 * @version     $Revision: 3938 $
 * @author      Guilherme Blanco <guilhermeblanco@hotmail.com>
 * @author      Konsta Vesterinen <kvesteri@cc.hut.fi>
 * @author      Roman Borschel <roman@code-factory.org>
 */
final class Query extends AbstractQuery
{
    /* Query STATES */
    /**
     * A query object is in CLEAN state when it has NO unparsed/unprocessed DQL parts.
     */
    const STATE_CLEAN  = 1;
    /**
     * A query object is in state DIRTY when it has DQL parts that have not yet been
     * parsed/processed. This is automatically defined as DIRTY when addDqlQueryPart
     * is called.
     */
    const STATE_DIRTY = 2;
    
    /* Query HINTS */
    /**
     * The refresh hint turns any query into a refresh query with the result that
     * any local changes in entities are overridden with the fetched values.
     * 
     * @var string
     */
    const HINT_REFRESH = 'doctrine.refresh';
    /**
     * The forcePartialLoad query hint forces a particular query to return
     * partial objects when partial objects in general are disallowed in the
     * configuration.
     * 
     * @var string
     */
    const HINT_FORCE_PARTIAL_LOAD = 'doctrine.forcePartialLoad';
    /**
     * The includeMetaColumns query hint causes meta columns like foreign keys and
     * discriminator columns to be selected and returned as part of the query result.
     * 
     * This hint does only apply to non-object queries.
     * 
     * @var string
     */
    const HINT_INCLUDE_META_COLUMNS = 'doctrine.includeMetaColumns';
    
    const HINT_CUSTOM_TREE_WALKERS = 'doctrine.customTreeWalkers';
    //const HINT_READ_ONLY = 'doctrine.readOnly';

    /**
     * @var integer $_state   The current state of this query.
     */
    private $_state = self::STATE_CLEAN;

    /**
     * @var string $_dql Cached DQL query.
     */
    private $_dql = null;

    /**
     * @var Doctrine\ORM\Query\ParserResult  The parser result that holds DQL => SQL information.
     */
    private $_parserResult;
    
    /**
     * @var integer The first result to return (the "offset").
     */
    private $_firstResult = null;
    
    /**
     * @var integer The maximum number of results to return (the "limit").
     */
    private $_maxResults = null;

    /**
     * @var CacheDriver  The cache driver used for caching queries.
     */
    private $_queryCache;

    /**
     * @var boolean Boolean value that indicates whether or not expire the query cache.
     */
    private $_expireQueryCache = false;

    /**
     * @var int Query Cache lifetime.
     */
    private $_queryCacheTTL;

    // End of Caching Stuff

    /**
     * Initializes a new Query instance.
     *
     * @param Doctrine\ORM\EntityManager $entityManager
     */
    public function __construct(EntityManager $entityManager)
    {
        parent::__construct($entityManager);
    }

    /**
     * Gets the SQL query/queries that correspond to this DQL query.
     *
     * @return mixed The built sql query or an array of all sql queries.
     * @override
     */
    public function getSql()
    {
        return $this->_parse()->getSqlExecutor()->getSqlStatements();
    }

    /**
     * Parses the DQL query, if necessary, and stores the parser result.
     * 
     * Note: Populates $this->_parserResult as a side-effect.
     *
     * @return Doctrine\ORM\Query\ParserResult
     */
    private function _parse()
    {
        if ($this->_state === self::STATE_DIRTY) {
            $parser = new Parser($this);
            $this->_parserResult = $parser->parse();
            $this->_state = self::STATE_CLEAN;
        }
        return $this->_parserResult;
    }

    /**
     * {@inheritdoc}
     *
     * @param array $params
     * @return Statement The resulting Statement.
     * @override
     */
    protected function _doExecute(array $params)
    {
        // Check query cache
        if ($queryCache = $this->getQueryCacheDriver()) {
            // Calculate hash for dql query.
            // TODO: Probably need to include query hints in hash calculation, because query hints
            //       can have influence on the SQL.
            $hash = md5($this->getDql() . 'DOCTRINE_QUERY_CACHE_SALT');
            $cached = ($this->_expireQueryCache) ? false : $queryCache->fetch($hash);

            if ($cached === false) {
                // Cache miss.
                $executor = $this->_parse()->getSqlExecutor();
                $queryCache->save($hash, $this->_parserResult, null);
            } else {
                // Cache hit.
                $this->_parserResult = $cached;
                $executor = $this->_parserResult->getSqlExecutor();
            }
        } else {
            $executor = $this->_parse()->getSqlExecutor();
        }

        $params = $this->_prepareParams($params);

        if ( ! $this->_resultSetMapping) {
            $this->_resultSetMapping = $this->_parserResult->getResultSetMapping();
        }

        return $executor->execute($this->_em->getConnection(), $params);
    }
    
    /**
     * {@inheritdoc}
     *
     * @override
     */
    protected function _prepareParams(array $params)
    {
        $sqlParams = array();
        
        $paramMappings = $this->_parserResult->getParameterMappings();
        foreach ($params as $key => $value) {
            if (is_object($value)) {
                $values = $this->_em->getClassMetadata(get_class($value))->getIdentifierValues($value);
                $sqlPositions = $paramMappings[$key];
                $sqlParams = array_merge($sqlParams, array_combine((array)$sqlPositions, (array)$values));
            } else if (is_bool($value)) {
                $boolValue = $this->_em->getConnection()->getDatabasePlatform()->convertBooleans($value);
                foreach ($paramMappings[$key] as $position) {
                    $sqlParams[$position] = $boolValue;
                }
            } else {
                foreach ($paramMappings[$key] as $position) {
                    $sqlParams[$position] = $value;
                }
            }
        }
        ksort($sqlParams);
        
        return array_values($sqlParams);
    }

    /**
     * Defines a cache driver to be used for caching queries.
     *
     * @param Doctrine_Cache_Interface|null $driver Cache driver
     * @return Query This query instance.
     */
    public function setQueryCacheDriver($queryCache)
    {
        $this->_queryCache = $queryCache;
        return $this;
    }

    /**
     * Returns the cache driver used for query caching.
     *
     * @return CacheDriver The cache driver used for query caching or NULL, if this
     * 					   Query does not use query caching.
     */
    public function getQueryCacheDriver()
    {
        if ($this->_queryCache) {
            return $this->_queryCache;
        } else {
            return $this->_em->getConfiguration()->getQueryCacheImpl();
        }
    }

    /**
     * Defines how long the query cache will be active before expire.
     *
     * @param integer $timeToLive How long the cache entry is valid
     * @return Query This query instance.
     */
    public function setQueryCacheLifetime($timeToLive)
    {
        if ($timeToLive !== null) {
            $timeToLive = (int) $timeToLive;
        }
        $this->_queryCacheTTL = $timeToLive;

        return $this;
    }

    /**
     * Retrieves the lifetime of resultset cache.
     *
     * @return int
     */
    public function getQueryCacheLifetime()
    {
        return $this->_queryCacheTTL;
    }

    /**
     * Defines if the query cache is active or not.
     *
     * @param boolean $expire Whether or not to force query cache expiration.
     * @return Query This query instance.
     */
    public function setExpireQueryCache($expire = true)
    {
        $this->_expireQueryCache = $expire;

        return $this;
    }

    /**
     * Retrieves if the query cache is active or not.
     *
     * @return bool
     */
    public function getExpireQueryCache()
    {
        return $this->_expireQueryCache;
    }

    /**
     * @override
     */
    public function free()
    {
        parent::free();
        $this->_dql = null;
        $this->_state = self::STATE_CLEAN;
    }

    /**
     * Sets a DQL query string.
     *
     * @param string $dqlQuery DQL Query
     */
    public function setDql($dqlQuery)
    {
        if ($dqlQuery !== null) {
            $this->_dql = $dqlQuery;
            $this->_state = self::STATE_DIRTY;
        }
    }

    /**
     * Returns the DQL query that is represented by this query object.
     *
     * @return string DQL query
     */
    public function getDql()
    {
        return $this->_dql;
    }

    /**
     * Returns the state of this query object
     * By default the type is Doctrine_ORM_Query_Abstract::STATE_CLEAN but if it appears any unprocessed DQL
     * part, it is switched to Doctrine_ORM_Query_Abstract::STATE_DIRTY.
     *
     * @see AbstractQuery::STATE_CLEAN
     * @see AbstractQuery::STATE_DIRTY
     *
     * @return integer Return the query state
     */
    public function getState()
    {
        return $this->_state;
    }

    /**
     * Method to check if an arbitrary piece of DQL exists
     *
     * @param string $dql Arbitrary piece of DQL to check for
     * @return boolean
     */
    public function contains($dql)
    {
        return stripos($this->getDql(), $dql) === false ? false : true;
    }
    
    /**
     * Sets the position of the first result to retrieve (the "offset").
     *
     * @param integer $firstResult The first result to return.
     * @return Query This query object.
     */
    public function setFirstResult($firstResult)
    {
        $this->_firstResult = $firstResult;
        return $this;
    }
    
    /**
     * Gets the position of the first result the query object was set to retrieve (the "offset").
     * Returns NULL if {@link setFirstResult} was not applied to this query.
     * 
     * @return integer The position of the first result.
     */
    public function getFirstResult()
    {
        return $this->_firstResult;
    }
    
    /**
     * Sets the maximum number of results to retrieve (the "limit").
     * 
     * @param integer $maxResults
     * @return Query This query object.
     */
    public function setMaxResults($maxResults)
    {
        $this->_maxResults = $maxResults;
        return $this;
    }
    
    /**
     * Gets the maximum number of results the query object was set to retrieve (the "limit").
     * Returns NULL if {@link setMaxResults} was not applied to this query.
     * 
     * @return integer Maximum number of results.
     */
    public function getMaxResults()
    {
        return $this->_maxResults;
    }
}