<?php

/* Copyright (c) 2019 Geert Bergman (geert@scrivo.nl), highlight.php
 *
 * 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. Neither the name of "highlight.js", "highlight.php", nor the names of its
 *    contributors may be used to endorse or promote products derived from this
 *    software without specific prior written permission.
 *
 * 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 HOLDER 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.
 */

namespace Highlight;

/**
 * @internal
 *
 * @since 9.16.0.0
 */
abstract class RegExUtils
{
    /**
     * @param string $value
     * @param bool   $global
     * @param bool   $case_insensitive
     *
     * @return RegEx
     */
    public static function langRe($value, $global, $case_insensitive)
    {
        // PCRE allows us to change the definition of "new line." The
        // `(*ANYCRLF)` matches `\r`, `\n`, and `\r\n` for `$`
        //
        //   https://www.pcre.org/original/doc/html/pcrepattern.html

        // PCRE requires us to tell it the string can be UTF-8, so the 'u' modifier
        // is required. The `u` flag for PCRE is different from JS' unicode flag.

        $escaped = preg_replace('#(?<!\\\)/#um', '\\/', $value);
        $regex = "/(*ANYCRLF){$escaped}/um" . ($case_insensitive ? "i" : "");

        return new RegEx($regex);
    }
}
