use std::borrow::Cow;
use std::error::Error;
use std::fmt;

use command_runner::CommandRunner;
use resources::Resource;
use symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};

pub struct MariaDBUser<'a, C: 'a + CommandRunner> {
  user_name: Cow<'a, str>,
  command_runner: &'a C
}

impl<'a, C: CommandRunner> MariaDBUser<'a, C> {
  pub fn new(user_name: Cow<'a, str>, command_runner: &'a C) -> Self {
    MariaDBUser { user_name, command_runner }
  }

  fn run_sql(&self, sql: &str) -> Result<String, Box<dyn Error>> {
    let b = try!(self.command_runner.get_output("mariadb", &["--skip-column-names", "-B", "-e", sql]));
    Ok(try!(String::from_utf8(b)))
  }
}

impl<'a, C: CommandRunner> fmt::Display for MariaDBUser<'a, C> {
  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
    write!(f, "MariaDB User {}", self.user_name)
  }
}

impl<'a, C: CommandRunner> Symbol for MariaDBUser<'a, C> {
  fn target_reached(&self) -> Result<bool, Box<dyn Error>> {
    Ok(try!(self.run_sql(&format!("SELECT User FROM mysql.user WHERE User = '{}' AND plugin = 'unix_socket'", self.user_name))).trim_end() == self.user_name)
  }

  fn execute(&self) -> Result<(), Box<dyn Error>> {
    try!(self.run_sql(&format!("GRANT ALL ON {0}.* TO {0} IDENTIFIED VIA unix_socket", self.user_name)));
    Ok(())
  }

  fn get_prerequisites(&self) -> Vec<Resource> {
    vec![ Resource::new("user", self.user_name.to_string()) ]
  }

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

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

#[cfg(test)]
mod test {
}