<?php
/**
 * Doctrine ORM
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE. This license can also be viewed
 * at http://hobodave.com/license.txt
 *
 * @category    DoctrineExtensions
 * @package     DoctrineExtensions\Paginate
 * @author      David Abdemoulaie <dave@hobodave.com>
 * @copyright   Copyright (c) 2010 David Abdemoulaie (http://hobodave.com/)
 * @license     http://hobodave.com/license.txt New BSD License
 */
namespace Doctrine\ORM\Tools\Pagination;

use Doctrine\ORM\Query\AST\ArithmeticExpression;
use Doctrine\ORM\Query\AST\SimpleArithmeticExpression;
use Doctrine\ORM\Query\TreeWalkerAdapter;
use Doctrine\ORM\Query\AST\SelectStatement;
use Doctrine\ORM\Query\AST\PathExpression;
use Doctrine\ORM\Query\AST\InExpression;
use Doctrine\ORM\Query\AST\NullComparisonExpression;
use Doctrine\ORM\Query\AST\InputParameter;
use Doctrine\ORM\Query\AST\ConditionalPrimary;
use Doctrine\ORM\Query\AST\ConditionalTerm;
use Doctrine\ORM\Query\AST\ConditionalExpression;
use Doctrine\ORM\Query\AST\ConditionalFactor;
use Doctrine\ORM\Query\AST\WhereClause;

/**
 * Replaces the whereClause of the AST with a WHERE id IN (:foo_1, :foo_2) equivalent.
 *
 * @category DoctrineExtensions
 * @package DoctrineExtensions\Paginate
 * @author David Abdemoulaie <dave@hobodave.com>
 * @copyright Copyright (c) 2010 David Abdemoulaie (http://hobodave.com/)
 * @license http://hobodave.com/license.txt New BSD License
 */
class WhereInWalker extends TreeWalkerAdapter
{

    /**
     * ID Count hint name.
     */
    const HINT_PAGINATOR_ID_COUNT = 'doctrine.id.count';

    /**
     * Primary key alias for query.
     */
    const PAGINATOR_ID_ALIAS = 'dpid';

    /**
     * Replaces the whereClause in the AST.
     *
     * Generates a clause equivalent to WHERE IN (:dpid_1, :dpid_2, ...)
     *
     * The parameter namespace (dpid) is defined by
     * the PAGINATOR_ID_ALIAS
     *
     * The total number of parameters is retrieved from
     * the HINT_PAGINATOR_ID_COUNT query hint.
     *
     * @param SelectStatement $AST
     *
     * @return void
     *
     * @throws \RuntimeException
     */
    public function walkSelectStatement(SelectStatement $AST)
    {
        $queryComponents = $this->_getQueryComponents();
        // Get the root entity and alias from the AST fromClause
        $from = $AST->fromClause->identificationVariableDeclarations;
        
        if (count($from) > 1) {
            throw new \RuntimeException("Cannot count query which selects two FROM components, cannot make distinction");
        }
        
        $fromRoot = reset($from);
        $rootAlias = $fromRoot->rangeVariableDeclaration->aliasIdentificationVariable;
        $rootClass = $queryComponents[$rootAlias]['metadata'];
        $identifierFieldName = $rootClass->getSingleIdentifierFieldName();
        
        $pathType = PathExpression::TYPE_STATE_FIELD;
        if (isset($rootClass->associationMappings[$identifierFieldName])) {
            $pathType = PathExpression::TYPE_SINGLE_VALUED_ASSOCIATION;
        }
        
        $pathExpression = new PathExpression(PathExpression::TYPE_STATE_FIELD | PathExpression::TYPE_SINGLE_VALUED_ASSOCIATION, $rootAlias, $identifierFieldName);
        $pathExpression->type = $pathType;
        
        $count = $this->_getQuery()->getHint(self::HINT_PAGINATOR_ID_COUNT);
        
        if ($count > 0) {
            $arithmeticExpression = new ArithmeticExpression();
            $arithmeticExpression->simpleArithmeticExpression = new SimpleArithmeticExpression(array(
                $pathExpression
            ));
            $expression = new InExpression($arithmeticExpression);
            $expression->literals[] = new InputParameter(":" . self::PAGINATOR_ID_ALIAS);
        } else {
            $expression = new NullComparisonExpression($pathExpression);
            $expression->not = false;
        }
        
        $conditionalPrimary = new ConditionalPrimary();
        $conditionalPrimary->simpleConditionalExpression = $expression;
        if ($AST->whereClause) {
            if ($AST->whereClause->conditionalExpression instanceof ConditionalTerm) {
                $AST->whereClause->conditionalExpression->conditionalFactors[] = $conditionalPrimary;
            } elseif ($AST->whereClause->conditionalExpression instanceof ConditionalPrimary) {
                $AST->whereClause->conditionalExpression = new ConditionalExpression(array(
                    new ConditionalTerm(array(
                        $AST->whereClause->conditionalExpression,
                        $conditionalPrimary
                    ))
                ));
            } elseif ($AST->whereClause->conditionalExpression instanceof ConditionalExpression || $AST->whereClause->conditionalExpression instanceof ConditionalFactor) {
                $tmpPrimary = new ConditionalPrimary();
                $tmpPrimary->conditionalExpression = $AST->whereClause->conditionalExpression;
                $AST->whereClause->conditionalExpression = new ConditionalTerm(array(
                    $tmpPrimary,
                    $conditionalPrimary
                ));
            }
        } else {
            $AST->whereClause = new WhereClause(new ConditionalExpression(array(
                new ConditionalTerm(array(
                    $conditionalPrimary
                ))
            )));
        }
    }
}
