import * as childProcess from 'child_process';

/**
 * open a file or uri using the default application for the file type.
 *
 * @return {ChildProcess} - the child process object.
 * @param {string} target - the file/uri to open.
 * @param {string} appName - (optional) the application to be used to open the
 *      file (for example, "chrome", "firefox")
 * @param {function(Error)} callback - called with null on success, or
 *      an error object that contains a property 'code' with the exit
 *      code of the process.
 */

export default function (target: string, appName: string | Function, callback?: Function) {
	let opener: string;

	if (typeof appName === 'function') {
		callback = appName;
		appName = null;
	}

	switch (process.platform) {
		case 'darwin':
			if (typeof appName === 'string') {
				opener = 'open -a "' + escape(appName) + '"';
			} else {
				opener = 'open';
			}
			break;
		case 'win32':
			// if the first parameter to start is quoted, it uses that as the title
			// so we pass a blank title so we can quote the file we are opening
			if (typeof appName === 'string') {
				opener = 'start "" "' + escape(appName) + '"';
			} else {
				opener = 'start ""';
			}
			break;
		default:
			if (typeof appName === 'string') {
				opener = escape(appName);
			} else {
				// use system installed Portlands xdg-open everywhere else
				opener = 'xdg-open';
			}
			break;
	}

	if (process.env.SUDO_USER) {
		opener = 'sudo -u ' + process.env.SUDO_USER + ' ' + opener;
	}
	console.log('open ' + opener + ' "' + escape(target) + '"');
	return childProcess.exec(opener + ' "' + escape(target) + '"');
}

function escape(s: string) {
	return s.replace(/"/g, '\\\"');
}