use clap::{Arg, Command, ArgAction};
use std::io;
use super::Cmd;

#[derive(Debug)]
pub struct Nproc {
    name: &'static str,
    path: Option<crate::Path>,
}

impl Default for Nproc {
    fn default() -> Self {
        Self {
            name: "nproc",
            path: Some(crate::Path::UsrBin),
        }
    }
}

impl Cmd for Nproc {
    fn name(&self) -> &str {
        self.name
    }

    fn cli(&self) -> clap::Command {
        Command::new(self.name)
            .author("Nathan Fisher")
            .about("Print the number of processing units available")
            .arg(
                Arg::new("ALL")
                    .help("Print the number of installed processors")
                    .short('a')
                    .long("all")
                    .action(ArgAction::SetTrue),
            )
    }

    fn run(&self, matches: Option<&clap::ArgMatches>) -> Result<(), Box<dyn std::error::Error>> {
        let Some(matches) = matches else {
            return Err(Box::new(io::Error::new(io::ErrorKind::Other, "no input")));
        };
        if matches.get_flag("ALL") {
            println!("{}", num_cpus::get());
        } else {
            println!("{}", num_cpus::get_physical());
        }
        Ok(())
    }

    fn path(&self) -> Option<crate::Path> {
        self.path
    }
}