<?php
/*
 * 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.
 *
 * @since   1.0
 * @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.
     * 
     * @var string
     * @todo Rename: HINT_OPTIMIZE
     */
    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';

    /**
     * An array of class names that implement Doctrine\ORM\Query\TreeWalker and
     * are iterated and executed after the DQL has been parsed into an AST.
     *
     * @var string
     */
    const HINT_CUSTOM_TREE_WALKERS = 'doctrine.customTreeWalkers';

    /**
     * A string with a class name that implements Doctrine\ORM\Query\TreeWalker
     * and is used for generating the target SQL from any DQL AST tree.
     *
     * @var string
     */
    const HINT_CUSTOM_OUTPUT_WALKER = 'doctrine.customOutputWalker';

    //const HINT_READ_ONLY = 'doctrine.readOnly';

    /**
     * @var string
     */
    const HINT_INTERNAL_ITERATION = 'doctrine.internal.iteration';

    /**
     * @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;
    
    /**
     * @var boolean Whether to use a query cache, if available. Defaults to TRUE.
     */
    private $_useQueryCache = true;

    // 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();
    }

    /**
     * Returns the corresponding AST for this DQL query.
     *
     * @return Doctrine\ORM\Query\AST\SelectStatement |
     *         Doctrine\ORM\Query\AST\UpdateStatement |
     *         Doctrine\ORM\Query\AST\DeleteStatement
     */
    public function getAST()
    {
        $parser = new Parser($this);
        return $parser->getAST();
    }

    /**
     * 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_CLEAN) {
            return $this->_parserResult;
        }
        
        // Check query cache.
        if ($this->_useQueryCache && ($queryCache = $this->getQueryCacheDriver())) {
            $hash = $this->_getQueryCacheId();
            $cached = $this->_expireQueryCache ? false : $queryCache->fetch($hash);
            if ($cached === false) {
                // Cache miss.
                $parser = new Parser($this);
                $this->_parserResult = $parser->parse();
                $queryCache->save($hash, $this->_parserResult, $this->_queryCacheTTL);
            } else {
                // Cache hit.
                $this->_parserResult = $cached;
            }
        } else {
            $parser = new Parser($this);
            $this->_parserResult = $parser->parse();
        }
        $this->_state = self::STATE_CLEAN;
        
        return $this->_parserResult;
    }

    /**
     * {@inheritdoc}
     */
    protected function _doExecute()
    {
        $executor = $this->_parse()->getSqlExecutor();

        // Prepare parameters
        $paramMappings = $this->_parserResult->getParameterMappings();

        if (count($paramMappings) != count($this->_params)) {
            throw QueryException::invalidParameterNumber();
        }

        $sqlParams = $types = array();

        foreach ($this->_params as $key => $value) {
            if ( ! isset($paramMappings[$key])) {
                throw QueryException::unknownParameter($key);
            }
            if (isset($this->_paramTypes[$key])) {
                foreach ($paramMappings[$key] as $position) {
                    $types[$position] = $this->_paramTypes[$key];
                }
            }

            if (is_object($value) && $this->_em->getMetadataFactory()->hasMetadataFor(get_class($value))) {
                $values = $this->_em->getUnitOfWork()->getEntityIdentifier($value);
                $sqlPositions = $paramMappings[$key];
                $sqlParams = array_merge($sqlParams, array_combine((array)$sqlPositions, $values));
            } else {
                foreach ($paramMappings[$key] as $position) {
                    $sqlParams[$position] = $value;
                }
            }
        }

        if ($sqlParams) {
            ksort($sqlParams);
            $sqlParams = array_values($sqlParams);
        }

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

        return $executor->execute($this->_em->getConnection(), $sqlParams, $types);
    }

    /**
     * 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;
    }
    
    /**
     * Defines whether the query should make use of a query cache, if available.
     * 
     * @param boolean $bool
     * @return @return Query This query instance.
     */
    public function useQueryCache($bool)
    {
        $this->_useQueryCache = $bool;
        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 $expire Whether or not to force query cache expiration.
     * @return Query This query instance.
     */
    public function expireQueryCache($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 $dqlQuery DQL Query
     * @return Doctrine\ORM\AbstractQuery
     */
    public function setDQL($dqlQuery)
    {
        if ($dqlQuery !== null) {
            $this->_dql = $dqlQuery;
            $this->_state = self::STATE_DIRTY;
        }
        return $this;
    }

    /**
     * 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;
        $this->_state = self::STATE_DIRTY;
        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;
        $this->_state = self::STATE_DIRTY;
        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;
    }

    /**
     * Executes the query and returns an IterableResult that can be used to incrementally
     * iterated over the result.
     *
     * @param array $params The query parameters.
     * @param integer $hydrationMode The hydration mode to use.
     * @return IterableResult
     */
    public function iterate(array $params = array(), $hydrationMode = self::HYDRATE_OBJECT)
    {
        $this->setHint(self::HINT_INTERNAL_ITERATION, true);
        return parent::iterate($params, $hydrationMode);
    }
    
    /**
     * {@inheritdoc}
     */
    public function setHint($name, $value)
    {
        $this->_state = self::STATE_DIRTY;
        return parent::setHint($name, $value);
    }
    
    /**
     * {@inheritdoc}
     */
    public function setHydrationMode($hydrationMode)
    {
        $this->_state = self::STATE_DIRTY;
        return parent::setHydrationMode($hydrationMode);
    }

    /**
     * Generate a cache id for the query cache - reusing the Result-Cache-Id generator.
     *
     * The query cache
     *
     * @return string
     */
    protected function _getQueryCacheId()
    {
        ksort($this->_hints);

        return md5(
            $this->getDql() . var_export($this->_hints, true) . 
            '&firstResult=' . $this->_firstResult . '&maxResult=' . $this->_maxResults .
            '&hydrationMode='.$this->_hydrationMode.'DOCTRINE_QUERY_CACHE_SALT'
        );
    }
}