use std::borrow::{Borrow, Cow};
use std::error::Error;
use std::fmt;
use std::fs;
use std::io;
use std::path::Path;
use std::str::FromStr;

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

#[derive(Debug, PartialEq)]
pub enum StorageDirection { Load, Save }

pub struct StoredDirectory<'a, S> where S: Storage {
  path: Cow<'a, str>,
  storage: S,
  dir: StorageDirection,
  command_runner: &'a CommandRunner
}

impl<'a, S> StoredDirectory<'a, S> where S: Storage {
  pub fn new(path: Cow<'a, str>, storage: S, dir: StorageDirection, command_runner: &'a CommandRunner) -> Self {
    StoredDirectory {
      path: path,
      storage: storage,
      dir: dir,
      command_runner: command_runner
    }
  }
}

impl<'a, S> fmt::Display for StoredDirectory<'a, S> where S: Storage {
  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
    write!(f, "Stored directory {} ({:?})", self.path, self.dir)
  }
}

impl<'a, S> Symbol for StoredDirectory<'a, S> where S: Storage {
  fn target_reached(&self) -> Result<bool, Box<Error>> {
    let metadata = fs::metadata(self.path.as_ref());
    // Check if dir exists
    if let Err(e) = metadata {
      return if e.kind() == io::ErrorKind::NotFound {
        Ok(self.dir == StorageDirection::Save)
      } else {
        Err(Box::new(e))
      };
    }
    if !metadata.unwrap().is_dir() {
      return Err(Box::new(io::Error::new(io::ErrorKind::AlreadyExists, "Could not create a directory, non-directory file exists")));
    }

    let dump_date = try!(self.storage.recent_date());
    let output = try!(self.command_runner.get_output("sh", &["-c", &format!("find {} -printf '%T@\\n' | sort -r | head -n1 | grep '^[0-9]\\+' -o", self.path)]));
    let modified_date = try!(u64::from_str(try!(String::from_utf8(output)).trim_right()));
    if if self.dir == StorageDirection::Save { modified_date > dump_date } else { dump_date > modified_date } {
      let output = try!(self.command_runner.run_with_args("diff", &["-rq", &try!(self.storage.read_filename()), self.path.borrow()]));
      match output.status.code() {
        Some(0) => Ok(true),
        Some(1) => Ok(false),
        _ => Err(try!(String::from_utf8(output.stderr)).into())
      }
    } else { Ok(true) }
  }

  fn execute(&self) -> Result<(), Box<Error>> {
    if self.dir == StorageDirection::Load {
      try!(self.command_runner.run_successfully("rm", &["-rf", self.path.borrow()]));
      self.command_runner.run_successfully("cp", &["-a", &try!(self.storage.read_filename()), self.path.borrow()])
    } else {
      self.command_runner.run_successfully("cp", &["-a", self.path.borrow(), &self.storage.write_filename()])
    }
  }

  fn get_prerequisites(&self) -> Vec<Resource> {
    if self.dir == StorageDirection::Save { return vec![]; }
    if let Some(parent) = Path::new(self.path.as_ref()).parent() {
      vec![ Resource::new("dir", parent.to_string_lossy()) ]
    } else {
      vec![]
    }
  }

  fn provides(&self) -> Option<Vec<Resource>> {
    if self.dir == StorageDirection::Load {
      Some(vec![ Resource::new("dir", self.path.to_string()) ])
    } else {
      None
    }
  }

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

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

#[cfg(test)]
mod test {
}