const unzip = require("unzip-stream");

/**
 * Convert a snake-cased string to a camel-cased one.
 * @param {string} str Original string.
 * @returns {string} Transformed string.
 */
const snakeToCamelCase = str => str.replace(/([-_][a-z])/gu, group =>
    group.toUpperCase().replace("-", "").replace("_", ""));

exports.snakeToCamelCase = snakeToCamelCase;

/**
 * Check if a value is a JS object.
 * @param {*} value Value to check.
 * @returns {boolean} Whether `value` is a JS object.
 */
const isObject = value => value !== null && typeof value === "object";

exports.isObject = isObject;

/**
 * Check if two arrays are equal in a shallow manner.
 * @param {Array} array1 First array.
 * @param {Array} array2 Second array.
 * @returns {boolean} Whether the two arrays are equal.
 */
const arraysEqual = (array1, array2) => (
    array1.length === array2.length &&
    array1.every((elt1, index) => elt1 === array2[index])
);

exports.arraysEqual = arraysEqual;

/**
 * Find a file in a zipped stream and unzip it.
 * @param {stream.Readable} data Input zipped stream.
 * @param {string} fileName Name of the file to find.
 * @returns {Promise.<stream.Readable>} Stream of the unzipped file.
 */
const unzipFile = (data, fileName) => new Promise((res, rej) => {
    // eslint-disable-next-line new-cap
    const stream = data.pipe(unzip.Parse());
    let found = false;

    stream.on("entry", entry => {
        if (entry.type !== "File" || entry.path !== fileName) {
            entry.autodrain();
            return;
        }

        found = true;
        res(entry);
    });

    stream.on("end", () => {
        if (!found) {
            rej(new Error(`File ${fileName} not found in archive`));
        }
    });

    stream.on("error", err => rej(err));
});

exports.unzipFile = unzipFile;