'use strict';
const path = require('path');
const childProcess = require('child_process');
const tasklist = require('tasklist');
const pify = require('pify');

const TEN_MEGABYTE = 1000 * 1000 * 10;

function win() {
	return tasklist().then(data => {
		return data.map(x => {
			return {
				pid: x.pid,
				name: x.imageName,
				cmd: x.imageName
			};
		});
	});
}

function def(opts) {
	opts = opts || {};

	const ret = {};
	const flags = (opts.all === false ? '' : 'a') + 'wwxo';

	return Promise.all(['comm', 'args', '%cpu', '%mem'].map(cmd => {
		return pify(childProcess.execFile)('ps', [flags, `pid,${cmd}`], {
			maxBuffer: TEN_MEGABYTE
		}).then(stdout => {
			for (let line of stdout.trim().split('\n').slice(1)) {
				line = line.trim();
				const pid = line.split(' ', 1)[0];
				const val = line.slice(pid.length + 1).trim();

				if (ret[pid] === undefined) {
					ret[pid] = {};
				}

				ret[pid][cmd] = val;
			}
		});
	})).then(() => {
		// Filter out inconsistencies as there might be race
		// issues due to differences in `ps` between the spawns
		return Object.keys(ret).filter(x => ret[x].comm && ret[x].args).map(x => {
			return {
				pid: parseInt(x, 10),
				name: path.basename(ret[x].comm),
				cmd: ret[x].args,
				cpu: ret[x]['%cpu'],
				memory: ret[x]['%mem']
			};
		});
	});
}

module.exports = process.platform === 'win32' ? win : def;