<?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.phpdoctrine.com>.
 */
/**
 * Doctrine_Hydrate_Alias
 * This class handles the creation of aliases for components in DQL query
 *
 * @package     Doctrine
 * @license     http://www.opensource.org/licenses/lgpl-license.php LGPL
 * @category    Object Relational Mapping
 * @link        www.phpdoctrine.com
 * @since       1.0
 * @version     $Revision$
 * @author      Konsta Vesterinen <kvesteri@cc.hut.fi>
 */
class Doctrine_Hydrate_Alias
{

    protected $shortAliases      = array();

    protected $shortAliasIndexes = array();

    public function clear()
    {
        $this->shortAliases = array();
        $this->shortAliasIndexes = array();
    }

    public function generateNewAlias($alias)
    {
        if (isset($this->shortAliases[$alias])) {
            // generate a new alias
            $name = substr($alias, 0, 1);
            $i    = ((int) substr($alias, 1));

            if ($i == 0) {
                $i = 1;
            }

            $newIndex  = ($this->shortAliasIndexes[$name] + $i);

            return $name . $newIndex;
        }

        return $alias;
    }

    public function hasAliasFor($tableName)
    {
        return (isset($this->shortAliases[$tableName]));
    }
    
    public function getComponentAlias($tableAlias)
    {
        if ( ! isset($this->shortAliases[$tableAlias])) {
            throw new Doctrine_Hydrate_Exception('Unknown table alias ' . $tableAlias);
        }
        return $this->shortAliases[$tableAlias];
    }

    public function getShortAliasIndex($alias)
    {
        if ( ! isset($this->shortAliasIndexes[$alias])) {
            return 0;
        }
        return $this->shortAliasIndexes[$alias];
    }
    public function generateShortAlias($componentAlias, $tableName)
    {
        $char   = strtolower(substr($tableName, 0, 1));

        $alias  = $char;

        if ( ! isset($this->shortAliasIndexes[$alias])) {
            $this->shortAliasIndexes[$alias] = 1;
        }
        while (isset($this->shortAliases[$alias])) {
            $alias = $char . ++$this->shortAliasIndexes[$alias];
        }

        $this->shortAliases[$alias] = $componentAlias;

        return $alias;
    }
    /**
     * getShortAlias
     * some database such as Oracle need the identifier lengths to be < ~30 chars
     * hence Doctrine creates as short identifier aliases as possible
     *
     * this method is used for the creation of short table aliases, its also
     * smart enough to check if an alias already exists for given component (componentAlias)
     *
     * @param string $componentAlias    the alias for the query component to search table alias for
     * @param string $tableName         the table name from which the table alias is being created
     * @return string                   the generated / fetched short alias
     */
    public function getShortAlias($componentAlias, $tableName = null)
    {
        $alias = array_search($componentAlias, $this->shortAliases);

        if ($alias !== false) {
            return $alias;
        }

        if ($tableName === null) {
            throw new Doctrine_Hydrate_Exception("Couldn't get short alias for " . $componentAlias);
        }

        return $this->generateShortAlias($componentAlias, $tableName);
    }
}