/**
 * This file is part of Haketilo.
 *
 * Function: Miscellaneous operations refactored to a separate file.
 *
 * Copyright (C) 2021 Wojtek Kosior
 * Copyright (C) 2021 jahoti
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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.
 *
 * As additional permission under GNU GPL version 3 section 7, you
 * may distribute forms of that code without the copy of the GNU
 * GPL normally required by section 4, provided you include this
 * license notice and, in case of non-source distribution, a URL
 * through which recipients can access the Corresponding Source.
 * If you modify file(s) with this exception, you may extend this
 * exception to your version of the file(s), but you are not
 * obligated to do so. If you do not wish to do so, delete this
 * exception statement from your version.
 *
 * As a special exception to the GPL, any HTML file which merely
 * makes function calls to this code, and for that purpose
 * includes it by reference shall be deemed a separate work for
 * copyright law purposes. If you modify this code, you may extend
 * this exception to your version of the code, but you are not
 * obligated to do so. If you do not wish to do so, delete this
 * exception statement from your version.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 *
 * I, Wojtek Kosior, thereby promise not to sue for violation of this file's
 * license. Although I request that you do not make use of this code in a
 * proprietary program, I am not going to enforce this in court.
 */

/*
 * uint8_to_hex is a separate function used in cryptographic functions and when
 * dealing with binary data.
 */
const uint8_to_hex =
      array => [...array].map(b => ("0" + b.toString(16)).slice(-2)).join("");
#EXPORT uint8_to_hex

/*
 * Asynchronously compute hex string representation of a sha256 digest of a
 * UTF-8 string.
 */
async function sha256_async(string) {
    const input_ab = new TextEncoder("utf-8").encode(string);
    const digest_ab = await crypto.subtle.digest("SHA-256", input_ab);
    return uint8_to_hex(new Uint8Array(digest_ab));
}
#EXPORT sha256_async

/*
 * Generate a unique value that can be computed synchronously and is impossible
 * to guess for a malicious website.
 */
function gen_nonce(length=16) {
    const random_data = new Uint8Array(length);
    crypto.getRandomValues(random_data);
    return uint8_to_hex(random_data);
}
#EXPORT gen_nonce

/* Check if some HTTP header might define CSP rules. */
const csp_header_regex =
      /^\s*(content-security-policy|x-webkit-csp|x-content-security-policy)\s*$/i;
#EXPORT csp_header_regex

/*
 * Check if url corresponds to a browser's special page (or a directory index in
 * case of `file://' protocol).
 */
#IF MOZILLA
const priv_reg = /^moz-extension:\/\/|^about:|^view-source:|^file:\/\/[^?#]*\/([?#]|$)/;
#ELIF CHROMIUM
const priv_reg = /^chrome(-extension)?:\/\/|^about:|^view-source:|^file:\/\/[^?#]*\/([?#]|$)/;
#ENDIF
#EXPORT  url => priv_reg.test(url)  AS is_privileged_url

/* Make it possible to serialize en Error object. */
function error_data_jsonifiable(error) {
    const jsonifiable = {};
    for (const property of ["name", "message", "fileName", "lineNumber"])
	jsonifiable[property] = error[property];

    return jsonifiable;
}
#EXPORT error_data_jsonifiable