use serial;
use serial::prelude::*;

use utilities::prelude::*;

use std::ffi::OsStr;
use std::time::Duration;

fn main() -> VerboseResult<()> {
    let mut port = open("/dev/ttyACM0")?;

    write(&mut port, "hello world")?;
    let msg = read(&mut port)?;

    println!("{}", msg);

    Ok(())
}

fn open<T: AsRef<OsStr> + ?Sized>(port: &T) -> VerboseResult<impl SerialPort> {
    let mut port = serial::open(port).map_err(|_| "could not open serial port")?;

    port.reconfigure(&|port_settings| {
        port_settings.set_baud_rate(serial::Baud9600)?;

        port_settings.set_char_size(serial::Bits8);
        port_settings.set_parity(serial::ParityNone);
        port_settings.set_stop_bits(serial::Stop1);
        port_settings.set_flow_control(serial::FlowNone);

        Ok(())
    })
    .map_err(|_| "failed configuring serial port")?;

    port.set_timeout(Duration::from_millis(1000))
        .map_err(|_| "failed setting time out for serial port")?;

    Ok(port)
}

fn read<T: SerialPort>(port: &mut T) -> VerboseResult<String> {
    let mut buf: Vec<u8> = (0..255).collect();

    port.read(&mut buf[..])
        .map_err(|_| "failed reading serial port")?;

    Ok(String::from_utf8(buf).map_err(|_| "failed converting utf8 buffer")?)
}

fn write<T: SerialPort>(port: &mut T, msg: &str) -> VerboseResult<()> {
    port.write(msg.as_bytes())
        .map_err(|_| "failed writing to serial port")?;

    Ok(())
}