use r2r::*;
use std::thread;
use std::env;
use std::collections::HashMap;

fn main() -> Result<(), ()> {
    let ctx = Context::create()?;
    let mut node = Node::create(ctx, "echo", "")?;

    let args: Vec<String> = env::args().collect();
    let topic = args.get(1).expect("provide a topic!");

    // run for a while to populate the topic list
    let mut count = 0;
    let mut nt = HashMap::new();
    while count < 50 {
        thread::sleep(std::time::Duration::from_millis(10));
        nt = node.get_topic_names_and_types()?;
        if nt.contains_key(topic) { break; }
        count += 1;
    }

    let type_name = nt.get(topic).and_then(|types|types.get(0));
    let type_name = match type_name {
        Some(tn) => tn,
        None => {
            eprintln!("Could not determine the type for the passed topic");
            return Err(());
        },
    };

    println!("topic: {}, type: {}", topic, type_name);

    // create echo topic
    let echo = &format!("{}_echo", topic);
    let echo_pub = node.create_publisher_untyped(echo, type_name)?;

    let cb = move |msg: serde_json::Value | {
        let s = serde_json::to_string_pretty(&msg).unwrap();
        println!("{}\n---\n", &s);
        echo_pub.publish(msg).unwrap();
    };

    let _subref = node.subscribe_untyped(topic, type_name, Box::new(cb))?;

    loop {
        node.spin_once(std::time::Duration::from_millis(100));
    }
}