use std::io::{self, Read, Write};
use std::time::Duration;

use clap::{App, AppSettings, Arg};

use serialport5::SerialPort;

fn main() {
    let matches = App::new("Serialport Example - Receive Data")
        .about("Reads data from a serial port and echoes it to stdout")
        .setting(AppSettings::DisableVersionFlag)
        .arg(
            Arg::new("port")
                .help("The device path to a serial port")
                .use_delimiter(false)
                .required(true),
        )
        .arg(
            Arg::new("baud")
                .help("The baud rate to connect at")
                .use_delimiter(false)
                .required(true)
                .validator(valid_baud),
        )
        .get_matches();
    let port_name = matches.value_of("port").unwrap();
    let baud_rate = matches.value_of("baud").unwrap().parse::<u32>().unwrap();

    let port = SerialPort::builder()
        .baud_rate(baud_rate)
        .read_timeout(Some(Duration::from_millis(10)))
        .write_timeout(Some(Duration::from_millis(10)))
        .open(port_name);

    match port {
        Ok(mut port) => {
            let mut serial_buf: Vec<u8> = vec![0; 1000];
            println!("Receiving data on {} at {} baud:", &port_name, &baud_rate);
            loop {
                match port.read(serial_buf.as_mut_slice()) {
                    Ok(t) => io::stdout().write_all(&serial_buf[..t]).unwrap(),
                    Err(ref e) if e.kind() == io::ErrorKind::TimedOut => (),
                    Err(e) => eprintln!("{:?}", e),
                }
            }
        }
        Err(e) => {
            eprintln!("Failed to open \"{}\". Error: {}", port_name, e);
            ::std::process::exit(1);
        }
    }
}

fn valid_baud(val: &str) -> Result<(), String> {
    val.parse::<u32>()
        .map(|_| ())
        .map_err(|_| format!("Invalid baud rate '{}' specified", val))
}