<?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\DBAL\Query\Expression;

/**
 * Composite expression is responsible to build a group of similar expression.
 *
 * @license     http://www.opensource.org/licenses/lgpl-license.php LGPL
 * @link        www.doctrine-project.org
 * @since       2.1
 * @author      Guilherme Blanco <guilhermeblanco@hotmail.com>
 * @author      Benjamin Eberlei <kontakt@beberlei.de>
 */
class CompositeExpression implements \Countable
{
    /**
     * Constant that represents an AND composite expression
     */
    const TYPE_AND = 'AND';
    
    /**
     * Constant that represents an OR composite expression
     */
    const TYPE_OR  = 'OR';
    
    /**
     * @var string Holds the instance type of composite expression
     */
    private $type;
    
    /**
     * @var array Each expression part of the composite expression
     */
    private $parts = array();
    
    /**
     * Constructor.
     * 
     * @param string $type Instance type of composite expression
     * @param array $parts Composition of expressions to be joined on composite expression
     */
    public function __construct($type, array $parts = array())
    {
        $this->type = $type;
        
        $this->addMultiple($parts);
    }
    
    /**
     * Adds multiple parts to composite expression.
     * 
     * @param array $args
     * 
     * @return CompositeExpression
     */
    public function addMultiple(array $parts = array())
    {
        foreach ((array) $parts as $part) {
            $this->add($part);
        }
        
        return $this;
    }
    
    /**
     * Adds an expression to composite expression.
     * 
     * @param mixed $part
     * @return CompositeExpression 
     */
    public function add($part)
    {
        if ( ! empty($part) || ($part instanceof self && $part->count() > 0)) {
            $this->parts[] = $part;
        }
        
        return $this;
    }
    
    /**
     * Retrieves the amount of expressions on composite expression.
     * 
     * @return integer 
     */
    public function count()
    {
        return count($this->parts);
    }
    
    /**
     * Retrieve the string representation of this composite expression.
     * 
     * @return string
     */
    public function __toString()
    {
        if (count($this->parts) === 1) {
            return (string) $this->parts[0];
        }
        
        return '(' . implode(') ' . $this->type . ' (', $this->parts) . ')';
    }
    
    /**
     * Return type of this composite expression (AND/OR)
     * 
     * @return string
     */
    public function getType()
    {
        return $this->type;
    }
}