<?php
/**
 * ExplainProcessor.php
 *
 * This file implements the processor for the EXPLAIN statements.
 *
 * PHP version 5
 *
 * LICENSE:
 * Copyright (c) 2010-2014 Justin Swanhart and André Rothe
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 *
 * @copyright 2010-2014 Justin Swanhart and André Rothe
 * @license   http://www.debian.org/misc/bsd.license  BSD License (3 Clause)
 *
 * @version   SVN: $Id$
 */

namespace PHPSQLParser\processors;

use PHPSQLParser\utils\ExpressionType;

/**
 * This class processes the EXPLAIN statements.
 *
 * @license http://www.debian.org/misc/bsd.license  BSD License (3 Clause)
 */
class ExplainProcessor extends AbstractProcessor
{
    protected function isStatement($keys, $needle = 'EXPLAIN')
    {
        $pos = array_search($needle, $keys, true);
        if (isset($keys[$pos + 1])) {
            return in_array($keys[$pos + 1], ['SELECT', 'DELETE', 'INSERT', 'REPLACE', 'UPDATE'], true);
        }

        return false;
    }

    // TODO: refactor that function
    public function process($tokens, $keys = [])
    {
        $base_expr    = '';
        $expr         = [];
        $currCategory = '';

        if ($this->isStatement($keys)) {
            foreach ($tokens as $token) {
                $trim = trim($token);
                $base_expr .= $token;

                if ($trim === '') {
                    continue;
                }

                $upper = strtoupper($trim);

                switch ($upper) {

                case 'EXTENDED':
                case 'PARTITIONS':
                    return ['expr_type' => ExpressionType::RESERVED, 'base_expr' => $token];
                    break;

                case 'FORMAT':
                    if ($currCategory === '') {
                        $currCategory = $upper;
                        $expr[]       = ['expr_type' => ExpressionType::RESERVED, 'base_expr' => $trim];
                    }
                    // else?
                    break;

                case '=':
                    if ($currCategory === 'FORMAT') {
                        $expr[] = ['expr_type' => ExpressionType::OPERATOR, 'base_expr' => $trim];
                    }
                    // else?
                    break;

                case 'TRADITIONAL':
                case 'JSON':
                    if ($currCategory === 'FORMAT') {
                        $expr[] = ['expr_type' => ExpressionType::RESERVED, 'base_expr' => $trim];

                        return ['expr_type' => ExpressionType::EXPRESSION, 'base_expr' => trim($base_expr),
                            'sub_tree'      => $expr, ];
                    }
                    // else?
                    break;

                default:
                // ignore the other stuff
                    break;
                }
            }

            return empty($expr) ? null : $expr;
        }

        foreach ($tokens as $token) {
            $trim = trim($token);

            if ($trim === '') {
                continue;
            }

            switch ($currCategory) {

            case 'TABLENAME':
                $currCategory = 'WILD';
                $expr[]       = ['expr_type' => ExpressionType::COLREF, 'base_expr' => $trim,
                    'no_quotes'              => $this->revokeQuotation($trim), ];
                break;

            case '':
                $currCategory = 'TABLENAME';
                $expr[]       = ['expr_type' => ExpressionType::TABLE, 'table' => $trim,
                    'no_quotes'              => $this->revokeQuotation($trim), 'alias' => false, 'base_expr' => $trim, ];
                break;

            default:
                break;
            }
        }

        return empty($expr) ? null : $expr;
    }
}
