use std::io::Result as IoResult;
use std::process::Command;
use std::process::Output;

pub trait CommandRunner {
  fn run_with_args(&self, program: &str, args: &[&str]) -> IoResult<Output>;
}

#[derive(Debug)]
pub struct StdCommandRunner;

impl CommandRunner for StdCommandRunner {
  fn run_with_args(&self, program: &str, args: &[&str]) -> IoResult<Output> {
    // FIXME: logger
    println!("{} {:?}", program, args);
    let res = Command::new(program).args(args).output();
    println!("{:?}", res);
    res
  }
}

#[derive(Debug)]
pub struct UserCommandRunner<'a, C> where C: 'a + CommandRunner {
  command_runner: &'a C,
  user_name: &'a str
}

impl<'a, C> UserCommandRunner<'a, C> where C: 'a + CommandRunner {
  pub fn new(user_name: &'a str, command_runner: &'a C) -> UserCommandRunner<'a, C> {
    UserCommandRunner {
      command_runner: command_runner,
      user_name: user_name
    }
  }
}

impl<'a, C> CommandRunner for UserCommandRunner<'a, C> where C: 'a + CommandRunner {
  fn run_with_args(&self, program: &str, args: &[&str]) -> IoResult<Output> {
    let mut new_args = vec![self.user_name, "-s", "/usr/bin/env", "--", program];
    new_args.extend_from_slice(args);
    self.command_runner.run_with_args("su", &new_args)
  }
}

#[cfg(test)]
mod test {
}