/**
 * Copyright 2025 Angus.Fenying <fenying@litert.org>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

function jsMaskFn(data: Buffer, maskKey: Buffer, offset: number): void {

    const l = data.byteLength;

    for (let i = 0, o = offset; i < l; i++, o++) {

        data[i] ^= maskKey[o & 3];
    }
}

type IMaskFn = (data: Buffer, maskKey: Buffer, offset: number) => void;

export const mask: IMaskFn = ((): IMaskFn => {

    try {

        // eslint-disable-next-line @typescript-eslint/no-require-imports, @typescript-eslint/no-var-requires
        return require('@litert/ws-utils').mask;
    }
    catch {

        return jsMaskFn;
    }
})();