use std::error::Error;
use std::fmt;
use std::str::FromStr;

use command_runner::CommandRunner;
use storage::Storage;
use symbols::{Action, OwnedSymbolAction, Symbol, SymbolAction, SymbolRunner};

pub struct DatabaseDump<'a, N, C, S>
where
  N: 'a + AsRef<str>,
  C: 'a + CommandRunner,
  S: Storage,
{
  db_name: N,
  storage: S,
  command_runner: &'a C,
}

impl<'a, N: AsRef<str>, C: CommandRunner, S: Storage> DatabaseDump<'a, N, C, S> {
  pub fn new(db_name: N, storage: S, command_runner: &'a C) -> Self {
    DatabaseDump {
      db_name,
      storage,
      command_runner,
    }
  }

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

impl<'a, N: AsRef<str>, C: CommandRunner, S: Storage> fmt::Display for DatabaseDump<'a, N, C, S> {
  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
    write!(f, "Dump MariaDB Database {}", self.db_name.as_ref())
  }
}

impl<'a, N: AsRef<str>, C: CommandRunner, S: Storage> Symbol for DatabaseDump<'a, N, C, S> {
  fn target_reached(&self) -> Result<bool, Box<dyn Error>> {
    let dump_date = self.storage.recent_date()?;
    let modified_date = try!(self.run_sql(&format!("select UNIX_TIMESTAMP(MAX(UPDATE_TIME)) from information_schema.tables WHERE table_schema = '{}'", self.db_name.as_ref())));
    if modified_date.trim_end() == "NULL" {
      return Ok(false);
    }
    Ok(u64::from_str(modified_date.trim_end())? <= dump_date)
  }

  fn execute(&self) -> Result<(), Box<dyn Error>> {
    self.command_runner.run_successfully(
      "sh",
      &[
        "-c",
        &format!(
          "mysqldump '{}' > {}",
          self.db_name.as_ref(),
          self.storage.write_filename()
        ),
      ],
    )
  }

  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 {}