use std::error::Error;
use std::fmt;
use std::fs;
use std::os::unix::fs::MetadataExt;

use users::get_user_by_name;

use symbols::Symbol;
use command_runner::CommandRunner;


pub struct Owner<'a, D> where D: AsRef<str> + fmt::Display {
  path: D,
  user_name: &'a str,
  command_runner: &'a CommandRunner
}

impl<'a, D> Owner<'a, D> where D: AsRef<str> + fmt::Display {
  pub fn new(path: D, user_name: &'a str, command_runner: &'a CommandRunner) -> Self {
    Owner { path: path, user_name: user_name, command_runner: command_runner }
  }
}

impl<'a, D> Symbol for Owner<'a, D> where D: AsRef<str> + fmt::Display {
  fn target_reached(&self) -> Result<bool, Box<Error>> {
    let actual_uid = fs::metadata(self.path.as_ref()).unwrap().uid();
    let target_uid = get_user_by_name(self.user_name).unwrap().uid();
    Ok(actual_uid == target_uid)
  }

  fn execute(&self) -> Result<(), Box<Error>> {
    try!(self.command_runner.run_with_args("chown", &[self.user_name, self.path.as_ref()]));
    Ok(())
  }
}

impl<'a, D> fmt::Display for Owner<'a, D> where D: AsRef<str> + fmt::Display {
  fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error>{
    write!(f, "Owner {} for {}", self.user_name, self.path)
  }
}