<?php

/*
 * This file is part of the Doctrine Bundle
 *
 * The code was originally distributed inside the Symfony framework.
 *
 * (c) Fabien Potencier <fabien@symfony.com>
 * (c) Doctrine Project, Benjamin Eberlei <kontakt@beberlei.de>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Doctrine\Bundle\DoctrineBundle\Twig;

/**
 * This class contains the needed functions in order to do the query highlighting
 *
 * @author Florin Patan <florinpatan@gmail.com>
 * @author Christophe Coevoet <stof@notk.org>
 */
class DoctrineExtension extends \Twig_Extension
{
    /**
     * Number of maximum characters that one single line can hold in the interface
     *
     * @var int
     */
    private $maxCharWidth = 100;

    /**
     * Define our functions
     *
     * @return array
     */
    public function getFilters()
    {
        return array(
            new \Twig_SimpleFilter('doctrine_minify_query', array($this, 'minifyQuery')),
            new \Twig_SimpleFilter('doctrine_pretty_query', 'SqlFormatter::format'),
            new \Twig_SimpleFilter('doctrine_replace_query_parameters', array($this, 'replaceQueryParameters')),
        );
    }

    /**
     * Get the possible combinations of elements from the given array
     *
     * @param array   $elements
     * @param integer $combinationsLevel
     *
     * @return array
     */
    private function getPossibleCombinations(array $elements, $combinationsLevel)
    {
        $baseCount = count($elements);
        $result = array();

        if (1 === $combinationsLevel) {
            foreach ($elements as $element) {
                $result[] = array($element);
            }

            return $result;
        }

        $nextLevelElements = $this->getPossibleCombinations($elements, $combinationsLevel - 1);

        foreach ($nextLevelElements as $nextLevelElement) {
            $lastElement = $nextLevelElement[$combinationsLevel - 2];
            $found = false;

            foreach ($elements as $key => $element) {
                if ($element == $lastElement) {
                    $found = true;
                    continue;
                }

                if ($found == true && $key < $baseCount) {
                    $tmp = $nextLevelElement;
                    $newCombination = array_slice($tmp, 0);
                    $newCombination[] = $element;
                    $result[] = array_slice($newCombination, 0);
                }
            }
        }

        return $result;
    }

    /**
     * Shrink the values of parameters from a combination
     *
     * @param array $parameters
     * @param array $combination
     *
     * @return string
     */
    private function shrinkParameters(array $parameters, array $combination)
    {
        array_shift($parameters);
        $result = '';

        $maxLength = $this->maxCharWidth;
        $maxLength -= count($parameters) * 5;
        $maxLength = $maxLength / count($parameters);

        foreach ($parameters as $key => $value) {
            $isLarger = false;

            if (strlen($value) > $maxLength) {
                $value = wordwrap($value, $maxLength, "\n", true);
                $value = explode("\n", $value);
                $value = $value[0];

                $isLarger = true;
            }
            $value = self::escapeFunction($value);

            if (!is_numeric($value)) {
                $value = substr($value, 1, -1);
            }

            if ($isLarger) {
                $value .= ' [...]';
            }

            $result .= ' '.$combination[$key].' '.$value;
        }

        return trim($result);
    }

    /**
     * Attempt to compose the best scenario minified query so that a user could find it without expanding it
     *
     * @param string  $query
     * @param array   $keywords
     * @param integer $required
     *
     * @return string
     */
    private function composeMiniQuery($query, array $keywords, $required)
    {
        // Extract the mandatory keywords and consider the rest as optional keywords
        $mandatoryKeywords = array_splice($keywords, 0, $required);

        $combinations = array();
        $combinationsCount = count($keywords);

        // Compute all the possible combinations of keywords to match the query for
        while ($combinationsCount > 0) {
            $combinations = array_merge($combinations, $this->getPossibleCombinations($keywords, $combinationsCount));
            $combinationsCount--;
        }

        // Try and match the best case query pattern
        foreach ($combinations as $combination) {
            $combination = array_merge($mandatoryKeywords, $combination);

            $regexp = implode('(.*) ', $combination).' (.*)';
            $regexp = '/^'.$regexp.'/is';

            if (preg_match($regexp, $query, $matches)) {
                $result = $this->shrinkParameters($matches, $combination);

                return $result;
            }
        }

        // Try and match the simplest query form that contains only the mandatory keywords
        $regexp = implode(' (.*)', $mandatoryKeywords).' (.*)';
        $regexp = '/^'.$regexp.'/is';

        if (preg_match($regexp, $query, $matches)) {
            $result = $this->shrinkParameters($matches, $mandatoryKeywords);

            return $result;
        }

        // Fallback in case we didn't managed to find any good match (can we actually have that happen?!)
        $result = substr($query, 0, $this->maxCharWidth);

        return $result;
    }

    /**
     * Minify the query
     *
     * @param string $query
     *
     * @return string
     */
    public function minifyQuery($query)
    {
        $result = '';
        $keywords = array();
        $required = 1;

        // Check if we can match the query against any of the major types
        switch (true) {
            case stripos($query, 'SELECT') !== false:
                $keywords = array('SELECT', 'FROM', 'WHERE', 'HAVING', 'ORDER BY', 'LIMIT');
                $required = 2;
                break;

            case stripos($query, 'DELETE') !== false:
                $keywords = array('DELETE', 'FROM', 'WHERE', 'ORDER BY', 'LIMIT');
                $required = 2;
                break;

            case stripos($query, 'UPDATE') !== false:
                $keywords = array('UPDATE', 'SET', 'WHERE', 'ORDER BY', 'LIMIT');
                $required = 2;
                break;

            case stripos($query, 'INSERT') !== false:
                $keywords = array('INSERT', 'INTO', 'VALUE', 'VALUES');
                $required = 2;
                break;

            // If there's no match so far just truncate it to the maximum allowed by the interface
            default:
                $result = substr($query, 0, $this->maxCharWidth);
        }

        // If we had a match then we should minify it
        if ($result == '') {
            $result = $this->composeMiniQuery($query, $keywords, $required);
        }

        // Remove unneeded boilerplate HTML
        $result = str_replace(array("<pre style='background:white;'", "</pre>"), array("<span", "</span>"), $result);

        return $result;
    }

    /**
     * Escape parameters of a SQL query
     * DON'T USE THIS FUNCTION OUTSIDE ITS INTENDED SCOPE
     *
     * @internal
     *
     * @param mixed $parameter
     *
     * @return string
     */
    public static function escapeFunction($parameter)
    {
        $result = $parameter;

        switch (true) {
            case is_string($result):
                $result = "'".addslashes($result)."'";
                break;

            case is_array($result):
                foreach ($result as &$value) {
                    $value = static::escapeFunction($value);
                }

                $result = implode(', ', $result);
                break;

            case is_object($result):
                $result = addslashes((string) $result);
                break;

            case null === $result:
                $result = 'NULL';
                break;

            case is_bool($result):
                $result = $result ? '1' : '0';
                break;
        }

        return $result;
    }

    /**
     * Return a query with the parameters replaced
     *
     * @param string $query
     * @param array  $parameters
     * @param bool   $highlight
     *
     * @return string
     */
    public function replaceQueryParameters($query, array $parameters, $highlight = true)
    {
        $i = 0;

        $result = preg_replace_callback(
            '/\?|((?<!:):[a-z0-9_]+)/i',
            function ($matches) use ($parameters, &$i) {
                $key = substr($matches[0], 1);
                if (!array_key_exists($i, $parameters) && (false === $key || !array_key_exists($key, $parameters))) {
                    return $matches[0];
                }

                $value = array_key_exists($i, $parameters) ? $parameters[$i] : $parameters[$key];
                $result = DoctrineExtension::escapeFunction($value);
                $i++;

                return $result;
            },
            $query
        );

        if ($highlight) {
            $result = \SqlFormatter::highlight($result);
            $result = str_replace(array("<pre ", "</pre>"), array("<span ", "</span>"), $result);
        }

        return $result;
    }

    /**
     * Get the name of the extension
     *
     * @return string
     */
    public function getName()
    {
        return 'doctrine_extension';
    }
}
