// paho-mqtt/examples/topic_publish.rs
//
// Example application for Paho MQTT Rust library.
//
//! This is a simple asynchronous publisher that uses a topic object to
//! repeatedly publish messages on the same topic.
//!
//! This sample demonstrates:
//!   - Connecting to an MQTT broker
//!   - Publishing a message asynchronously
//!   - Using a 'Topic' object to publish multiple messages to the same topic.
//!

/*******************************************************************************
 * Copyright (c) 2017-2023 Frank Pagliughi <fpagliughi@mindspring.com>
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v2.0
 * and Eclipse Distribution License v1.0 which accompany this distribution.
 *
 * The Eclipse Public License is available at
 *    http://www.eclipse.org/legal/epl-v20.html
 * and the Eclipse Distribution License is available at
 *   http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *    Frank Pagliughi - initial implementation and documentation
 *******************************************************************************/

use paho_mqtt as mqtt;
use std::{env, process};

const QOS: i32 = 1;

/////////////////////////////////////////////////////////////////////////////

fn main() {
    // Initialize the logger from the environment
    env_logger::init();

    let host = env::args()
        .nth(1)
        .unwrap_or_else(|| "mqtt://localhost:1883".to_string());

    // Create a client & define connect options
    let cli = mqtt::AsyncClient::new(host).unwrap_or_else(|err| {
        println!("Error creating the client: {}", err);
        process::exit(1);
    });

    let conn_opts = mqtt::ConnectOptions::new();

    // Connect and wait for it to complete or fail
    if let Err(e) = cli.connect(conn_opts).wait() {
        println!("Unable to connect: {:?}", e);
        process::exit(1);
    }

    // Create a topic and publish to it
    println!("Publishing messages on the 'test' topic");
    let topic = mqtt::Topic::new(&cli, "test", QOS);
    for _ in 0..5 {
        let tok = topic.publish("Hello there");

        if let Err(e) = tok.wait() {
            println!("Error sending message: {:?}", e);
            break;
        }
    }

    // Disconnect from the broker
    let tok = cli.disconnect(None);
    tok.wait().unwrap();
}