use std::error::Error;
use std::fmt;
use std::fs;
use std::io;
use std::path::Path;

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

pub struct Dir<D> where D: AsRef<str> {
  path: D
}

impl<D> Dir<D> where D: AsRef<str> {
  pub fn new(path: D) -> Self {
    Dir { path }
  }
}

impl<D> Symbol for Dir<D> where D: AsRef<str> {
  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(false)
      } else {
        Err(Box::new(e))
      };
    }
    if metadata.unwrap().is_dir() {
      Ok(true)
    } else {
      Err(Box::new(io::Error::new(io::ErrorKind::AlreadyExists, "Could not create a directory, non-directory file exists")))
    }
  }

  fn execute(&self) -> Result<(), Box<Error>> {
    fs::create_dir(self.path.as_ref()).map_err(|e| Box::new(e) as Box<Error>)
  }

  fn get_prerequisites(&self) -> Vec<Resource> {
    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>> {
    Some(vec![ Resource::new("dir", self.path.as_ref()) ])
  }

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

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

impl<D> fmt::Display for Dir<D> where D: AsRef<str> {
  fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error>{
    write!(f, "Dir {}", self.path.as_ref())
  }
}