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

use command_runner::CommandRunner;
use resources::Resource;
use symbols::Symbol;

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

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

  fn run_sql(&self, sql: &str) -> Result<String, Box<Error>> {
    let output = try!(self.command_runner.run_with_args("mariadb", &["--skip-column-names", "-e", sql]));
    if output.status.code() != Some(0) {
      return Err(try!(String::from_utf8(output.stderr)).into());
    }
    Ok(try!(String::from_utf8(output.stdout)))
  }
}

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

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

  fn execute(&self) -> Result<(), Box<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()) ]
  }
}

#[cfg(test)]
mod test {
}