/*
 * Copyright (C) 2023-2025  Yomitan Authors
 * Copyright (C) 2021-2022  Yomichan Authors
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

/**
 * Decodes the contents of an ArrayBuffer using UTF8.
 * @param {ArrayBuffer} arrayBuffer The input ArrayBuffer.
 * @returns {string} A UTF8-decoded string.
 */
export function arrayBufferUtf8Decode(arrayBuffer) {
    try {
        return new TextDecoder('utf-8').decode(arrayBuffer);
    } catch (e) {
        return decodeURIComponent(escape(arrayBufferToBinaryString(arrayBuffer)));
    }
}

/**
 * Converts the contents of an ArrayBuffer to a base64 string.
 * @param {ArrayBuffer} arrayBuffer The input ArrayBuffer.
 * @returns {string} A base64 string representing the binary content.
 */
export function arrayBufferToBase64(arrayBuffer) {
    return btoa(arrayBufferToBinaryString(arrayBuffer));
}

/**
 * Converts the contents of an ArrayBuffer to a binary string.
 * @param {ArrayBuffer} arrayBuffer The input ArrayBuffer.
 * @returns {string} A string representing the binary content.
 */
export function arrayBufferToBinaryString(arrayBuffer) {
    const bytes = new Uint8Array(arrayBuffer);
    try {
        return String.fromCharCode(...bytes);
    } catch (e) {
        let binary = '';
        for (let i = 0, ii = bytes.byteLength; i < ii; ++i) {
            binary += String.fromCharCode(bytes[i]);
        }
        return binary;
    }
}

/**
 * Converts a base64 string to an ArrayBuffer.
 * @param {string} content The binary content string encoded in base64.
 * @returns {ArrayBuffer} A new `ArrayBuffer` object corresponding to the specified content.
 */
export function base64ToArrayBuffer(content) {
    const binaryContent = atob(content);
    const length = binaryContent.length;
    const array = new Uint8Array(length);
    for (let i = 0; i < length; ++i) {
        array[i] = binaryContent.charCodeAt(i);
    }
    return array.buffer;
}
