extern crate simple_munin_plugin;

mod load {
    use std::io::Read;
    use std::fs::File;
    use simple_munin_plugin::*;


    const FIELD: &'static str = "load";

    pub struct LoadPlugin;

    impl LoadPlugin {
        pub fn new() -> LoadPlugin {
            LoadPlugin
        }

        pub fn parse(s: &str) -> Option<&str> {
            s.split_whitespace().nth(1)
        }
    }

    impl MuninNodePlugin for LoadPlugin {
        fn config(&self) {
            println!(r#"graph_title Load average
graph_args --base 1000 -l 0
graph_vlabel load
graph_scale no
graph_category system
graph_info Load average (written in Rust)
{0}.label load
{0}.info 5 minutes average"#, FIELD);
            Self::print_if_env(Level::Warning, FIELD);
            Self::print_if_env(Level::Critical, FIELD);
        }

        fn run(&self) {
            let mut file = File::open("/proc/loadavg").expect("couldn't open file");
            let mut content = String::new();
            file.read_to_string(&mut content).expect("couldn't read content");
            //    println!("content: {}\n", content);
            println!("{}.value {}", FIELD, Self::parse(&content).expect("couldn't parse content"));
        }
    }
}

use simple_munin_plugin::*;

fn main() {
    let plugin = load::LoadPlugin::new();
    std::process::exit(plugin.start());
}


#[cfg(test)]
mod tests {
    use super::*;


    #[test]
    fn test_parse() {
        assert_eq!(Some("1.02"), LoadPlugin::parse("0.01 1.02 3.02 1/183 9236\n"));
        assert_eq!(None, LoadPlugin::parse(""));
    }

}