use tokio::{
    io::{AsyncBufReadExt, AsyncWriteExt, BufReader},
    net::TcpListener,
    sync::broadcast,
};

#[tokio::main]
async fn main() {
    // Set up a TCP listenner to listen for incoming tcp requests
    let listener = TcpListener::bind("127.0.0.1:8080").await.unwrap();

    // Setting up broadcast channel: A channel that will accept messages and broadcast them to everyone connected to the TCP server
    // the channel accepts an i32 that is the maximum number of messages the channel can retain at any given time
    let (sender, _receiver) = broadcast::channel(10);

    // First loop accept all the tcp client requests
    loop {
        // prevent the compiler error when we try to access something in a loop when it was initialized outside of the loop
        let sender = sender.clone();

        let mut receiver = sender.subscribe();

        // accept the requests
        let (mut socket, addr) = listener.accept().await.unwrap();

        tokio::spawn(async move {
            // Splitting the TCP socket into read/write halves
            let (reader, mut writer) = socket.split();

            let mut buffer_reader = BufReader::new(reader);

            let mut line: String = String::new();

            // second loop keeps receving input from that one client going
            loop {
                tokio::select! {
                    result = buffer_reader.read_line(&mut line) => {
                        if result.unwrap() == 0{
                            break;
                        }
                        // send items to the broadcast channel
                        sender.send((line.clone(), addr)).unwrap();
                        // clear the input buffer
                        line.clear();
                    }

                    result = receiver.recv() => {
                        let (msg, other_addr) = result.unwrap();

                        if addr != other_addr {
                            writer.write_all(msg.as_bytes()).await.unwrap();
                        }
                    }
                }
            }
        });
    }
}