use std::{
    env,
    fs::File,
    io::{BufRead as _, BufReader},
    path::PathBuf,
    time::Duration,
};

use eyre::ContextCompat as _;

pub(crate) struct Config {
    pub(crate) netdev: Option<String>,
    pub(crate) interval: Duration,
}

impl Config {
    const CONFIG_FILE: &'static str = ".config/pfs/linkspeed";

    pub(crate) fn from_file() -> eyre::Result<Self> {
        let config_file = PathBuf::from(env::var("HOME")?).join(Self::CONFIG_FILE);

        let mut config = Self::default();

        if let Ok(file) = File::open(&config_file) {
            let file = BufReader::new(file);

            for line in file.lines() {
                let line = line?;

                match &line {
                    line if line.starts_with("netdev") => {
                        config.netdev = Some(Self::read_config_value(line)?.to_string());
                    }
                    line if line.starts_with("interval") => {
                        let interval = Self::read_config_value(line)?.parse::<f64>()?;
                        config.interval = Duration::from_secs_f64(interval);
                    }
                    _ => {}
                }
            }
        }

        Ok(config)
    }

    fn read_config_value(line: &str) -> eyre::Result<&str> {
        let val = line
            .split('=')
            .nth(1)
            .wrap_err("failed to parse value".to_string())?
            .trim();

        Ok(val)
    }
}

impl Default for Config {
    fn default() -> Self {
        Config {
            netdev: None,
            interval: Duration::from_secs(1),
        }
    }
}