<?php
/**
 * Elastica tools
 *
 * @category Xodoa
 * @package Elastica
 * @author Nicolas Ruflin <hide@address.com>
 * @author Thibault Duplessis <hide@address.com>
 * @author Oleg Zinchenko <hide@address.com>
 */
class Elastica_Util
{
    /**
     * Replace the following reserved words: AND OR NOT
     * and
     * escapes the following terms: + - && || ! ( ) { } [ ] ^ " ~ * ? : \
     *
     * @param  string $term Query term to replare and escape
     * @return string Replaced and escaped query term
     * @link http://lucene.apache.org/java/2_4_0/queryparsersyntax.html#Boolean%20operators
     * @link http://lucene.apache.org/java/2_4_0/queryparsersyntax.html#Escaping%20Special%20Characters
     */
    public static function replaceBooleanWordsAndEscapeTerm($term)
    {
        $result = $term;
        $result = self::replaceBooleanWords($result);
        $result = self::escapeTerm($result);

        return $result;
    }

    /**
     * Escapes the following terms (because part of the query language)
     * + - && || ! ( ) { } [ ] ^ " ~ * ? : \
     *
     * @param  string $term Query term to escape
     * @return string Escaped query term
     * @link http://lucene.apache.org/java/2_4_0/queryparsersyntax.html#Escaping%20Special%20Characters
     */
    public static function escapeTerm($term)
    {
        $result = $term;
        // \ escaping has to be first, otherwise escaped later once again
        $chars = array('\\', '+', '-', '&&', '||', '!', '(', ')', '{', '}', '[', ']', '^', '"', '~', '*', '?', ':');

        foreach ($chars as $char) {
            $result = str_replace($char, '\\' . $char, $result);
        }

        return $result;
    }

    /**
     * Replace the following reserved words (because part of the query language)
     * AND OR NOT
     *
     * @param  string $term Query term to replace
     * @return string Replaced query term
     * @link http://lucene.apache.org/java/2_4_0/queryparsersyntax.html#Boolean%20operators
     */
    public static function replaceBooleanWords($term)
    {
        $replacementMap = array('AND'=>'&&', 'OR'=>'||', 'NOT'=>'!');
        $result = strtr($term, $replacementMap);

        return $result;
    }

    /**
     * Converts a snake_case string to CamelCase
     *
     * For example: hello_world to HelloWorld
     *
     * @param  string $string snake_case string
     * @return string CamelCase string
     */
    public static function toCamelCase($string)
    {
        return str_replace(" ", "", ucwords(str_replace("_", " ", $string)));
    }

    /**
     * Converts a CamelCase string to snake_case
     *
     * For Example HelloWorld to hello_world
     *
     * @param  string $string CamelCase String to Convert
     * @return string SnakeCase string
     */
    public static function toSnakeCase($string)
    {
        $string = preg_replace('/([A-Z])/', '_$1', $string);

        return strtolower(substr($string,1));
    }

    /**
     * Converts given time to format: 1995-12-31T23:59:59Z
     *
     * This is the lucene date format
     *
     * @param  int    $date Date input (could be string etc.) -> must be supported by strtotime
     * @return string Converted date string
     */
    public static function convertDate($date)
    {
        if (is_int($date)) {
            $timestamp = $date;
        } else {
            $timestamp = strtotime($date);
        }
        $string =  date('Y-m-d\TH:i:s\Z', $timestamp);

        return $string;
    }
}