use std::env;
use std::fs;
use std::io::prelude::*;
use std::ffi::OsString;
use std::process::{Command, Stdio, Output};
use regex::Regex;
use users::get_current_username;

fn exit(error: String) {
	eprintln!("error: {}", error);
	std::process::exit(0);
}

fn main() {

	let superuser = OsString::from("root");

	match get_current_username() {
		Some(user) => match user {
			_ if user == superuser => parse_command(),
			_ => exit("Must be run as root.".to_string()),
		}
		None => exit("The current user does not exist.".to_string()),
	}

}

fn parse_command() {

	let args: Vec<String> = env::args().collect();

	match args.get(1) {
		Some(p) => match p {
			_ if p == "setup-user" => setup_user(args[2].to_string(), args[3].to_string()),
			_ if p == "reload-nginx" => reload_nginx(),
			_ if p == "reload-tor" => reload_tor(),
			_ if p == "reload-twins" => reload_twins(),
			_ if p == "gemini-new-certificate" => gemini_new_certificate(args[2].to_string()),
			_ if p == "le-install" => le_install(args[2].to_string()),
			_ if p == "export-tor" => export_tor(args[2].to_string(), args[3].to_string()),
			_ => exit("This subcommand doesn't exists.".to_string()),
		}
		None => exit("You must specify a subcommand.".to_string()),
	}

}

fn gemini_new_certificate(domain: String) {

	let mut common_name: String = "/CN=".to_owned();
	common_name += &domain.to_string();

	let mut key_file: String = "/var/local/twins/tls/".to_owned();
	key_file += &domain.to_string();
	key_file += &".key".to_string().to_owned();

	let mut cert_file: String = "/var/local/twins/tls/".to_owned();
	cert_file += &domain.to_string();
	cert_file += &".crt".to_string().to_owned();

	let output = Command::new("/usr/bin/openssl")
		.arg("req")
		.arg("-subj")
		.arg(common_name)
		.arg("-new")
		.arg("-newkey")
		.arg("ED25519")
		.arg("-days")
		.arg("3650")
		.arg("-nodes")
		.arg("-x509")
		.arg("-keyout")
		.arg(&key_file)
		.arg("-out")
		.arg(&cert_file)
		.output()
		.expect("failed to execute process");
	print_output(output);

	let output = Command::new("/usr/bin/chmod")
		.arg("400")
		.arg(&key_file)
		.output()
		.expect("Failed to change key file mode to 400");
	print_output(output);

	let output = Command::new("/usr/bin/chown")
		.arg("twins:twins")
		.arg(key_file)
		.output()
		.expect("Failed to chown key file to twins:twins");
	print_output(output);

	let output = Command::new("/usr/bin/chmod")
		.arg("400")
		.arg(&cert_file)
		.output()
		.expect("Failed to change key file mode to 400");
	print_output(output);

	let output = Command::new("/usr/bin/chown")
		.arg("twins:twins")
		.arg(cert_file)
		.output()
		.expect("Failed to chown key file to twins:twins");
	print_output(output);
}

fn le_install(domain: String) {

	let output = Command::new("/usr/bin/certbot")
		.arg("certonly")
		.arg("--nginx")
		// Using ECDSA
		//.arg("--key-type")
		//.arg("ecdsa")
		//.arg("--elliptic-curve")
		//.arg("secp384r1")
		// Using RSA
		.arg("--key-type")
		.arg("rsa")
		.arg("--rsa-key-size")
		.arg("3072")
		.arg("-d")
		.arg(&domain)
		.output()
		.expect("failed to execute process");
	print_output(output);
}

fn export_tor(username: String, dir: String) {
	if is_string_lowercase(username.to_string()) {
		if is_string_lowercase(dir.to_string()) {
			let mut src_path: String = "/var/lib/tor-instances/niver/keys/".to_owned();
			src_path += &dir.to_string();
			src_path += &"/hostname".to_string().to_owned();

			let mut dest_path: String = "/srv/ht/".to_owned();
			dest_path += &username.to_string();
			dest_path += &"/ht/".to_string().to_owned();
			dest_path += &dir.to_string();
			dest_path += &"/hostname".to_string().to_owned();

			match fs::copy(src_path, &dest_path) {
				Err(why) => panic!("Error while copying file (fs::copy) : {}", why),
				Ok(process) => process,
			};

			let output = Command::new("/usr/bin/chown")
				.arg("php-niver:ht")
				.arg(&dest_path)
				.output()
				.expect("failed to execute process");

			print_output(output);

			let output = Command::new("/usr/bin/chmod")
				.arg("440")
				.arg(dest_path)
				.output()
				.expect("failed to execute process");

			print_output(output);
		} else {
			exit("The dirname must be composed only of lowercase letters.".to_string());
		}
	} else {
		exit("The username must be composed only of lowercase letters.".to_string());
	}
}

fn reload_tor() {
	let output = Command::new("/usr/bin/systemctl")
		.arg("reload")
		.arg("tor@niver")
		.output()
		.expect("Error while reloading Tor config");
	print_output(output);
}

fn reload_nginx() {
	let output = Command::new("/usr/bin/systemctl")
		.arg("reload")
		.arg("nginx")
		.output()
		.expect("Error while reloading Nginx config");
	print_output(output);
}

fn reload_twins() {
	let output = Command::new("/usr/bin/systemctl")
		.arg("reload")
		.arg("twins")
		.output()
		.expect("Error while reloading Twins");
	print_output(output);
}

fn setup_user(username: String, password: String) {

	if username.chars().count() < 32 {
		if password.chars().count() < 1024 {
			if is_string_lowercase(username.to_string()) {

				let username1 = &username;
				let username2 = &username;
				let username3 = &username;
				let username4 = &username;
				newser(username1.to_string());
				pwd(username2.to_string(), password);
				chown_root(username3.to_string());
				quota(username4.to_string());

			} else {
				exit("The username must be composed only of lowercase letters.".to_string());
			}
		} else {
			exit("The password must be shorter than 1024 characters.".to_string());
		}
	} else {
		exit("The username must be shorter than 32 characters.".to_string());
	}
}

// Creates a new user in the group 'ht', which is available only over SFTP
fn newser(username: String) {
	let output = Command::new("/usr/sbin/useradd")
		.arg(&username)
		.arg("--create-home")
		.arg("--skel")
		.arg("/usr/local/share/niver/skel")
		.arg("--base-dir")
		.arg("/srv/ht")
		.arg("--gid")
		.arg("ht")
		.arg("--shell")
		.arg("/usr/sbin/nologin")

		.output()
		.expect("failed to execute process");
	print_output(output);
}

// Changes password of the newly created user
fn pwd(username: String, password: String) {

	// line must be in the form username:password
	let mut line: String = username.to_string();
	line += &":".to_string().to_owned();
	line += &password.to_owned();

	let process = match Command::new("/usr/sbin/chpasswd")
			.stdin(Stdio::piped())
			.stdout(Stdio::piped())
			.spawn() {
		Err(why) => panic!("couldn't spawn chpasswd: {}", why),
		Ok(process) => process,
	};

	match process.stdin.unwrap().write_all(line.as_bytes()) {
		Err(why) => panic!("couldn't write to chpasswd stdin: {}", why),
		Ok(_) => println!("sent username:password to chpasswd"),
	}

	let mut s = String::new();
	match process.stdout.unwrap().read_to_string(&mut s) {
		Err(why) => panic!("couldn't read chpasswd stdout: {}", why),
		Ok(_) => print!("chpasswd responded with:\n{}", s),
	}
}

// Chown /srv/ht/username to root:root
fn chown_root(username: String) {

	let mut path = "/srv/ht/".to_string();

	path += &username;

	let output = Command::new("/usr/bin/chown")
		.arg("root:root")
		.arg(&path)
		.output()
		.expect("Failed to chown /srv/ht/<username> to root:root");
	print_output(output);

	let output = Command::new("/usr/bin/chmod")
		.arg("755")
		.arg(path)
		.output()
		.expect("Failed to chmod /srv/ht/<username> to 755");
	print_output(output);
}

// Set disk usage limit to the user by copying another user quota
fn quota(username: String) {
	let output = Command::new("/usr/sbin/edquota")
		.arg("-p")
		.arg("niver-quota")
		.arg(&username)
		.output()
		.expect("failed to execute process");
	print_output(output);
}

fn is_string_lowercase(stri: String) -> bool {

	let re = Regex::new("^[[:lower:]]+$").unwrap();
	let matching = re.is_match(&stri);
	if matching {
		return true;
	} else {
		return false;
	}
}

fn print_output(output: Output) {
	println!("status: {}", output.status);
	println!("stdout: {}", String::from_utf8_lossy(&output.stdout));
	println!("stderr: {}", String::from_utf8_lossy(&output.stderr));
	assert!(output.status.success());
}