/*
 * This file is part of Adblock Plus <https://adblockplus.org/>,
 * Copyright (C) 2006-2017 eyeo GmbH
 *
 * Adblock Plus is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 3 as
 * published by the Free Software Foundation.
 *
 * Adblock Plus is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
 */

// We are currently limited to ECMAScript 5 in this file, because it is being
// used in the browser tests. See https://issues.adblockplus.org/ticket/4796

/**
 * Converts filter text into regular expression string
 * @param {string} text as in Filter()
 * @return {string} regular expression representation of filter text
 */
function filterToRegExp(text)
{
  return text
    // remove multiple wildcards
    .replace(/\*+/g, "*")
    // remove anchors following separator placeholder
    .replace(/\^\|$/, "^")
    // escape special symbols
    .replace(/\W/g, "\\$&")
    // replace wildcards by .*
    .replace(/\\\*/g, ".*")
    // process separator placeholders (all ANSI characters but alphanumeric
    // characters and _%.-)
    .replace(/\\\^/g, "(?:[\\x00-\\x24\\x26-\\x2C\\x2F\\x3A-\\x40\\x5B-\\x5E\\x60\\x7B-\\x7F]|$)")
    // process extended anchor at expression start
    .replace(/^\\\|\\\|/, "^[\\w\\-]+:\\/+(?!\\/)(?:[^\\/]+\\.)?")
    // process anchor at expression start
    .replace(/^\\\|/, "^")
    // process anchor at expression end
    .replace(/\\\|$/, "$")
    // remove leading wildcards
    .replace(/^(\.\*)/, "")
    // remove trailing wildcards
    .replace(/(\.\*)$/, "");
}

if (typeof exports != "undefined")
  exports.filterToRegExp = filterToRegExp;