use std::error::Error;
use std::fmt;

use crate::command_runner::CommandRunner;

use crate::symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};

pub struct Cron<'r, C: AsRef<str>, U: AsRef<str>, R: CommandRunner> {
  user: U,
  content: C,
  command_runner: &'r R,
}

impl<'r, U: AsRef<str>, R: CommandRunner> Cron<'r, String, U, R> {
  pub fn new<C: AsRef<str>>(user: U, content: C, command_runner: &'r R) -> Self {
    Cron {
      user,
      content: String::from(content.as_ref()) + "\n",
      command_runner,
    }
  }
}

impl<C: AsRef<str>, U: AsRef<str>, R: CommandRunner> Symbol for Cron<'_, C, U, R> {
  fn target_reached(&self) -> Result<bool, Box<dyn Error>> {
    let tab = self
      .command_runner
      .get_output("crontab", args!["-l", "-u", self.user.as_ref()])?;
    Ok(tab == self.content.as_ref().as_bytes())
  }

  fn execute(&self) -> Result<(), Box<dyn Error>> {
    let output = self.command_runner.run_with_args_and_stdin(
      "crontab",
      args!["-u", self.user.as_ref(), "-",],
      self.content.as_ref(),
    )?;
    if !output.status.success() {
      return Err(String::from_utf8(output.stderr)?.into());
    }
    Ok(())
  }

  fn as_action<'a>(&'a self, runner: &'a dyn SymbolRunner) -> Box<dyn Action + 'a> {
    Box::new(SymbolAction::new(runner, self))
  }

  fn into_action<'a>(self: Box<Self>, runner: &'a dyn SymbolRunner) -> Box<dyn Action + 'a>
  where
    Self: 'a,
  {
    Box::new(OwnedSymbolAction::new(runner, *self))
  }
}

impl<C: AsRef<str>, U: AsRef<str>, R: CommandRunner> fmt::Display for Cron<'_, C, U, R> {
  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
    write!(f, "Cron {}", self.user.as_ref())
  }
}