//
//#region Imports ...
const os = require('os');
const process = require('process');
const { exec } = require("child_process");
const XFileTools = require('../tools/x-file.tools');
//#endregion

//
//#region Constants ...
//
const OS = {
    Aix: 'aix',
    Darwin: 'darwin',
    FreeBSD: 'freebsd',
    Linux: 'linux',
    OpenBSD: 'openbsd',
    SnOS: 'sunos',
    Windows: 'win32'
}

//
const isWindows = process.platform === OS.Windows;
//#endregion

//
//#region Actions ...
//
//#region Pure shell commands ...
/**
 * execute a command using NodeJS on shell ...
 * 
 * @param {string} cmd command to execute ...
 * @param {string} cwd working directory ...
 * 
 * @returns Promise<any, errr> instance ...
 */
function execute(cmd, cwd) {
    return new Promise((resolve, reject) => {
        //
        if (!cmd || cmd.toString().length === 0 || (cwd && !XFileTools.isDirectoryExists(cwd))) {
            reject('invalid args ...');
            return;
        }

        //
        exec(cmd, { cwd }, (err, result, stdError) => {
            //
            if (err) {
                reject(err);
                return;
            }

            //
            if (stdError) {
                //
                // reject(stdError);
                // return;
            }

            //
            resolve(result);
        });
    });
};

/**
 * determines a command exists on host or not ...
 * 
 * @param {string} name specific command name ...
 * 
 * @returns boolean Promise ...
 */
function checkCommandExists(name) {
    return new Promise(resolve => {
        //
        if (!name) {
            resolve(false);
            return;
        }

        //
        const cmd = isWindows ? `${name} >nul 2>&1` : `type ${name} >/dev/null 2>&1`;
        execute(cmd).then(result => {
            resolve(true);
        })
            .catch(err => {
                resolve(false);
            });
    });
}
//#endregion

//
//#region required commands state ...
/**
 * check al required commands exists or not ...
 * 
 * @returns 
 */
async function isRequiredCommandsExists() {
    //
    let result = false;

    //
    // const isTarExists = await isTarCommandExists();
    // const isCatExists = await isCatCommandExists();
    // const isGrepExists = await isGrepCommandExists();
    // const isSedExists = await isSedCommandExists();
    // const isNpmExists = await isNpmCommandExists();
    const isNgExists = await isNgCommandExists();
    const isIonicExists = await isIonicCommandExists();
    const isCordovaExists = await isCordovaCommandExists();

    //
    result = isNgExists &&
        isIonicExists &&
        isCordovaExists;

    //
    return result;
}

/**
 * retrieve required commands state object ...
 * 
 * @returns 
 */
async function getRequiredCommandsStates() {
    //
    const result = {};

    //
    // const isTarExists = await isTarCommandExists();
    // const isCatExists = await isCatCommandExists();
    // const isGrepExists = await isGrepCommandExists();
    // const isSedExists = await isSedCommandExists();
    // const isNpmExists = await isNpmCommandExists();
    const isNgExists = await isNgCommandExists();
    const isIonicExists = await isIonicCommandExists();
    const isCordovaExists = await isCordovaCommandExists();

    //
    result['ng'] = isNgExists;
    result['ionic'] = isIonicExists;
    result['cordova'] = isCordovaExists;

    //
    return result;
}
//#endregion

//
//#region Commonly used Command Checkers ...
/**
 * determines ng command exists or not ...
 * 
 * @returns 
 */
function isNgCommandExists() {
    return checkCommandExists('ng');
}

/**
 * determines ionic command exists or not ...
 * 
 * @returns 
 */
function isIonicCommandExists() {
    return checkCommandExists('ionic');
}

/**
 * determines cordova command exists or not ...
 * 
 * @returns 
 */
function isCordovaCommandExists() {
    return checkCommandExists('cordova');
}
//#endregion
//#endregion

//
// Module Exports ...
module.exports = {
    //
    execute,
    checkCommandExists,
    isRequiredCommandsExists,
    getRequiredCommandsStates,

    //
    // isFxCommandExists,
    // isTarCommandExists,
    // isCatCommandExists,
    // isSedCommandExists,
    // isNpmCommandExists,
    // isGrepCommandExists,
    isNgCommandExists,
    isIonicCommandExists,
    isCordovaCommandExists,
}