// Copyright Open Logistics Foundation
//
// Licensed under the Open Logistics Foundation License 1.3.
// For details on the licensing terms, see the LICENSE file.
// SPDX-License-Identifier: OLFL-1.3

//! Simple UDP echo example
//!
//! When running the example, please specify the socket address (ip address + port number) of a UDP
//! echo server in the environment variable `BG77_REMOTE`.
//!
//! This example will print some minimal output over serial uart and RTT.

#![no_std]
#![no_main]

pub use hal::stm32 as pac;
pub use stm32l4xx_hal as hal;

use core::{str::FromStr, time::Duration};

use hal::prelude::*;

use panic_probe as _;

mod boards;
use boards::common;

#[cortex_m_rt::entry]
fn main() -> ! {
    let mut driver = boards::board_setup();

    let bg77 = quectel_bg77::Bg77ClientStack::new(&mut driver);

    // IP address of your TCP echo server: read from environment variable
    let socket_addr_str = core::env!(
        "BG77_REMOTE",
        "Please specify the socket address of your udp echo server, e.g. '192.168.1.1:12345'"
    );
    let socket_addr = match embedded_nal::SocketAddr::from_str(socket_addr_str) {
        Ok(s) => s,
        Err(e) => {
            log::info!("Could not parse socket address: {:?}", e);
            #[allow(clippy::empty_loop)]
            loop {}
        }
    };

    // UDP echo example
    if let Err(e) = udp_client_example(bg77, socket_addr) {
        log::error!("Example failed: {:?}", e);
    } else {
        log::info!("Example successful");
    }

    #[allow(clippy::empty_loop)]
    loop {}
}

fn udp_client_example<E, BG77>(
    mut bg77: BG77,
    socket_addr: embedded_nal::SocketAddr,
) -> Result<(), E>
where
    E: core::fmt::Debug,
    BG77: embedded_nal::UdpClientStack<Error = E>,
{
    // This only fails if all sockets are currently in use
    let mut socket = bg77.socket().unwrap();

    log::info!("Connect socket to {}", socket_addr);
    bg77.connect(&mut socket, socket_addr)?;

    let tx = b"Hello, BG77!\n";
    log::info!("Send message");
    // bg77.send() currently never returns `nb::Error::WouldBlock` so `nb::block!` is not
    // required here but this would be the correct usage of a generic
    // `embedded_nal::UdpClientStack`
    nb::block!(bg77.send(&mut socket, tx))?;
    log::info!("Message sent");

    loop {
        log::info!("Receive");
        let mut rx_buf = [0u8; 100];
        match bg77.receive(&mut socket, &mut rx_buf) {
            Ok((received, _)) => {
                log::info!("Received {} bytes: {:?}", received, &rx_buf[..received]);
                log::info!("Stop");
                // The driver implements `Drop` for the sockets so it is closed automatically. In
                // general, calling `TcpClientStack::close(socket)` would be required.
                return Ok(());
            }
            Err(nb::Error::WouldBlock) => {
                log::info!("Nothing received, retrying in a second");
                let mut timer = common::Timer::new();
                timer.start(Duration::from_secs(1));
                nb::block!(timer.wait()).unwrap();
            }
            Err(nb::Error::Other(e)) => {
                return Err(e);
            }
        }
    }
}