mpd_client 0.3.0

use mpd_client::{Client, Command, Frame, Subsystem};

use tokio::net::TcpStream;
use tokio::stream::StreamExt;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    // This could also be a UnixStream
    let connection = TcpStream::connect("localhost:6600").await?;

    // The client is used to issue commands, and state_changes is an async stream of state change
    // notifications
    let (client, mut state_changes) = Client::connect(connection).await?;

    // Get the song playing right as we connect
    let initial = client.command(Command::new("currentsong")).await?;
    print_current_song(initial);

    // Wait for state change notifications being emitted by MPD
    while let Some(subsys) = state_changes.next().await {
        let subsys = subsys?;

        if subsys == Subsystem::Player {
            let current = client.command(Command::new("currentsong")).await?;
            print_current_song(current);
        }
    }

    Ok(())
}

fn print_current_song(response: Frame) {
    let values = response.values_as_map();

    if values.is_empty() {
        println!("(none)");
    } else {
        println!(
            "\"{}\" by \"{}\"",
            display_value(values.get("Title")),
            display_value(values.get("Artist"))
        );
    }
}

fn display_value<'a>(value: Option<&'_ Vec<&'a str>>) -> &'a str {
    value.and_then(|v| v.first()).unwrap_or(&"(empty value)")
}