//! Имитатор термометра

use rand::prelude::*;
use std::io::Read;
use std::net::{IpAddr, SocketAddr};
use std::str::FromStr;
use std::sync::Arc;
use std::time::Duration;

struct Params {
    addr: SocketAddr,
    interval: Duration,
}

const CONFIG_FILE: &str = "thermometer_mock.cfg";

fn read_parameters_from_file() -> Result<Params, std::io::Error> {
    let mut file = std::fs::File::open(CONFIG_FILE)?;
    let mut content = String::new();
    file.read_to_string(&mut content)?;
    let lines = content.split("\n").collect::<Vec<&str>>();
    let addr = lines
        .first()
        .map(|v| SocketAddr::from_str(v))
        .ok_or(std::io::Error::other("no address found in config file"))?
        .map_err(std::io::Error::other)?;
    let interval = lines
        .get(1)
        .map(|v| v.parse::<u64>())
        .ok_or(std::io::Error::other("no interval found in config file"))?
        .map(Duration::from_millis)
        .map_err(std::io::Error::other)?;
    Ok(Params { addr, interval })
}

fn generate_temperature() -> f32 {
    rand::rng().random_range(18.0..23.0)
}

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let params = read_parameters_from_file()?;
    let rt = tokio::runtime::Builder::new_current_thread().enable_all().build()?;
    rt.block_on(async move {
        let socket = Arc::new(tokio::net::UdpSocket::bind(SocketAddr::new(IpAddr::from([127, 0, 0, 1]), 10003)).await?);
        let mut interval = tokio::time::interval(params.interval);
        loop {
            interval.tick().await;
            let new_temperature = generate_temperature();
            let data = new_temperature.to_le_bytes();
            socket.send_to(&data, &params.addr).await?;
        }
    })
}