import { isArray, isString, replace } from 'lodash';
import { relative } from 'path';

export function firstOf(aValue: string | string[] | null | undefined): string | null | undefined {
    // test
    if (isString(aValue)) {
        return aValue;
    }
    if (isArray(aValue)) {
        // extract the first element
        const array: any[] = aValue;
        if (array.length > 0) {
            return firstOf(array[0]);
        }
        // nothing
        return undefined;
    }
    // nothing
    return aValue;
}

export function arrayOf(aValue: string | string[] | null | undefined): string[] | null | undefined {
    // test
    if (isString(aValue)) {
        return [aValue];
    }
    // default fallback
    return aValue;
}

export function relativePath(aSrc: string, aDst: string): string {
    return replace(relative(aSrc, aDst), /\\/g, '/');
}