import { BaseEncodingOptions, exists, lstat } from "fs";
import { mkdir, writeFile } from 'fs/promises';
import { type } from "os";
import { promisify } from "util";

const _exists = promisify(exists);
const _lstat = promisify(lstat);

/**
 * Function to create a File
 * @param fileName Read the File.
 * @param content content which should be stored
 * @param options The options to write the file. See original docu: https://nodejs.org/dist/latest-v8.x/docs/api/fs.html#fs_fs_writefile_file_data_options_callback
 */
export async function createFile(fileName: string, content: string, options?: (BaseEncodingOptions & { mode?: string | number; flag?: string | number; }) | "ascii" | "utf8" | "utf-8" | "utf16le" | "ucs2" | "ucs-2" | "base64" | "latin1" | "binary" | "hex") {
    // Based on the OS select the Path Element.
    const SPLITCHAR = type() === 'Linux' ? '/' : '\\';
    // Adapt the File Pathes
    fileName = type() === 'Linux' ? fileName.replace(/\\\\/g, '/') : fileName.replace(/\//g, '\\');

    // Split the Path into different segements.
    const pathParts = fileName.split(SPLITCHAR);

    // Pop the File.
    pathParts.pop();

    // Create the Path / Directories
    await createPath(pathParts.join(SPLITCHAR))

    // Wirte the File.
    await writeFile(fileName, content, options)

    return fileName;
}

/**
 * Function to create a File
 * @param path Read the File.
 * @param content content which should be stored
 * @param options The options to write the file. See original docu: https://nodejs.org/dist/latest-v8.x/docs/api/fs.html#fs_fs_writefile_file_data_options_callback
 */
export async function createPath(path: string) {
    // Based on the OS select the Path Element.
    const SPLITCHAR = type() === 'Linux' ? '/' : '\\';
    // Adapt the File Pathes
    path = type() === 'Linux' ? path.replace(/\\\\/g, '/') : path.replace(/\//g, '\\');

    // Split the Path into different segements.
    const pathParts = path.split('/');

    if (pathParts.length > 0) {
        /** Check if the given Path Ends with a File Name */
        if (pathParts[pathParts.length - 1].indexOf('.') !== -1) {
            pathParts.pop();
        }

        // Reassemble the Segments like that:
        //
        // C:\\Test\\SubFolder\\AnotherFolder
        // Split up:
        // => fileParts = [C: , Test , SubFolder, AnotherFolder]
        //
        // Reassemble:
        // 1) C:
        // 2) C:\\Test
        // 3) C:\\Test\\SubFolder
        // 4) ...
        //
        // Everytime after an assembly Check whether the assembled
        // path exists, otherwise create that folder and go on.       

        for (const [idx, folder] of pathParts.entries()) {
            // Assemble the Path.
            const currentPath = pathParts.slice(0, idx + 1).join(SPLITCHAR);
            // Test and create the Folder
            const urlExists = await _exists(currentPath);
            // Test if the provided Path exists or not.
            if (currentPath && !urlExists) {
                await mkdir(currentPath);
            } else if (currentPath && urlExists && (await _lstat(currentPath)).isFile()) {

                throw Error('Cant create File at the specified path. The given URL contains a File. See "' + currentPath + '"');
            }
        }
    }

    return path;
}