const COUCH_NAME_CHARS = 'abcdefghijklmnopqrstuvwxyz';

/**
 * Get a random string which can be used for many things in RxDB.
 * The returned string is guaranteed to be a valid database name or collection name
 * and also to be a valid JavaScript variable name.
 * 
 * @link http://stackoverflow.com/a/1349426/3443137
 */
export function randomToken(length: number = 10): string {
    let text = '';

    for (let i = 0; i < length; i++) {
        text += COUCH_NAME_CHARS.charAt(Math.floor(Math.random() * COUCH_NAME_CHARS.length));
    }

    return text;
}


/**
 * A random string that is never inside of any storage
 */
export const RANDOM_STRING = 'Fz7SZXPmYJujkzjY1rpXWvlWBqoGAfAX';

/**
 * uppercase first char
 */
export function ucfirst(str: string): string {
    str += '';
    const f = str.charAt(0)
        .toUpperCase();
    return f + str.substr(1);
}

/**
 * removes trailing and ending dots from the string
 */
export function trimDots(str: string): string {
    let start = 0;
    let end = str.length;
    // charCode 46 is a dot ('.')
    while (start < end && str.charCodeAt(start) === 46) {
        start++;
    }
    while (end > start && str.charCodeAt(end - 1) === 46) {
        end--;
    }
    if (start === 0 && end === str.length) {
        return str;
    }
    return str.substring(start, end);
}

/**
 * @link https://stackoverflow.com/a/44950500/3443137
 */
export function lastCharOfString(str: string): string {
    return str.charAt(str.length - 1);
}

/**
 * returns true if the given name is likely a folder path
 */
export function isFolderPath(name: string) {
    // do not check, if foldername is given
    if (
        name.includes('/') || // unix
        name.includes('\\') // windows
    ) {
        return true;
    } else {
        return false;
    }
}


/**
 * @link https://gist.github.com/andreburgaud/6f73fd2d690b629346b8
 * @link https://stackoverflow.com/a/76240378/3443137
 */
export function arrayBufferToString(arrayBuffer: Uint8Array<ArrayBuffer>) {
    return new TextDecoder().decode(arrayBuffer);
}

export function stringToArrayBuffer(str: string): Uint8Array<ArrayBuffer> {
    return new TextEncoder().encode(str);
}


export function normalizeString(str: string): string {
    return str.trim().replace(/[\n\s]+/g, '');
}