const realpath = require('fs').realpath;
const stat = require('fs').stat;

async function fileExists(file) {
    if (file === undefined) {
        throw new Error('can not check the existence of an undefined file');
    }
    let path;
    try {
        path = await resolvePath(file);
    } catch (err) {
        throw err;
    }
    return await new Promise((resolve, reject) => {
        stat(path, (err, stats) => {
            if (err) {
                reject(err);
            }
            resolve({path, stats});
        })
    });
}

async function resolvePath(file) {
    if (file === undefined) {
        throw new Error('can not resolve a path to an undefined file');
    }
    return await new Promise((resolve, reject) => {
        realpath(file, (err, resolvedPath) => {
            if (err) {
                reject(new Error('resolving path \'' + file + '\' encountered an error >>> ' + err));
            }
            resolve(resolvedPath);
        })
    });
}

module.exports = {
    fileExists,
    resolvePath
};