'use strict';

const assert = require('assert'),
    BoxError = require('./boxerror.js'),
    child_process = require('child_process'),
    debug = require('debug')('box:shell'),
    once = require('./once.js'),
    util = require('util');

exports = module.exports = {
    sudo,

    promises: {
        exec: util.promisify(exec),
        execArgs: util.promisify(execArgs),
        sudo: util.promisify(sudo)
    }
};

const SUDO = '/usr/bin/sudo';

// default encoding utf8, no shell, separate args
function execArgs(tag, file, args, options, callback) {
    assert.strictEqual(typeof tag, 'string');
    assert.strictEqual(typeof file, 'string');
    assert(Array.isArray(args));
    assert.strictEqual(typeof options, 'object');
    assert.strictEqual(typeof callback, 'function');

    debug(`${tag} exec: ${file}`);

    const execOptions = Object.assign({ encoding: 'utf8', shell: false }, options);

    // https://github.com/nodejs/node/issues/25231
    const cp = child_process.execFile(file, args, execOptions, function (error, stdout, stderr) {
        let e = null;
        if (error) {
            e = new BoxError(BoxError.SHELL_ERROR, `${tag} errored with code ${error.code} message ${error.message}`);
            e.stdout = stdout; // when promisified, this is the way to get stdout
            e.stderr = stderr; // when promisified, this is the way to get stderr

            debug(`${tag}: ${file} with args ${args.join(' ')} errored`, error);
        }

        callback(e, stdout);
    });

    if (options.input) {
        cp.stdin.write(options.input);
        cp.stdin.end();
    }
}

// default encoding utf8, shell, handles input, full command
function exec(tag, cmd, options, callback) {
    assert.strictEqual(typeof tag, 'string');
    assert.strictEqual(typeof cmd, 'string');
    assert.strictEqual(typeof options, 'object');
    assert.strictEqual(typeof callback, 'function');

    const [file, ...args] = cmd.split(' ');
    execArgs(tag, file, args, options, callback);
}

// use this when you are afraid of how arguments will split up
function spawn(tag, file, args, options, callback) {
    assert.strictEqual(typeof tag, 'string');
    assert.strictEqual(typeof file, 'string');
    assert(Array.isArray(args));
    assert.strictEqual(typeof options, 'object');
    assert.strictEqual(typeof callback, 'function');

    callback = once(callback); // exit may or may not be called after an 'error'

    if (options.ipc) options.stdio = ['pipe', 'pipe', 'pipe', 'ipc'];

    debug(tag + ' spawn: %s %s', file, args.join(' ').replace(/\n/g, '\\n'));
    const cp = child_process.spawn(file, args, options);
    let stdoutResult = '';

    cp.stdout.on('data', function (data) {
        debug(tag + ' (stdout): %s', data.toString('utf8'));
        stdoutResult += data.toString('utf8');
    });

    cp.stderr.on('data', function (data) {
        debug(tag + ' (stderr): %s', data.toString('utf8'));
    });

    cp.on('exit', function (code, signal) {
        if (code || signal) debug(tag + ' code: %s, signal: %s', code, signal);
        if (code === 0) return callback(null, stdoutResult);

        let e = new BoxError(BoxError.SHELL_ERROR, `${tag} exited with code ${code} signal ${signal}`);
        e.code = code;
        e.signal = signal;
        callback(e);
    });

    cp.on('error', function (error) {
        debug(tag + ' code: %s, signal: %s', error.code, error.signal);
        let e = new BoxError(BoxError.SHELL_ERROR, `${tag} errored with code ${error.code} message ${error.message}`);
        callback(e);
    });

    return cp;
}

function sudo(tag, args, options, callback) {
    assert.strictEqual(typeof tag, 'string');
    assert(Array.isArray(args));
    assert.strictEqual(typeof options, 'object');
    assert.strictEqual(typeof callback, 'function');

    let sudoArgs = [ '-S' ]; // -S makes sudo read stdin for password
    if (options.preserveEnv) sudoArgs.push('-E'); // -E preserves environment
    if (options.ipc) sudoArgs.push('--close-from=4'); // keep the ipc open. requires closefrom_override in sudoers file

    const cp = spawn(tag, SUDO, sudoArgs.concat(args), options, callback);
    cp.stdin.end();
    if (options.onMessage) cp.on('message', options.onMessage);
    return cp;
}