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: AsRef<Path>> {
  path: D,
}

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

impl<D: AsRef<Path>> Symbol for Dir<D> {
  fn target_reached(&self) -> Result<bool, Box<dyn Error>> {
    if !self.path.as_ref().exists() {
      return Ok(false);
    }
    let metadata = fs::metadata(self.path.as_ref())?;
    if !metadata.is_dir() {
      return Err(Box::new(io::Error::new(
        io::ErrorKind::AlreadyExists,
        "Could not create a directory, non-directory file exists",
      )));
    }
    Ok(true)
  }

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

  fn get_prerequisites(&self) -> Vec<Resource> {
    if let Some(parent) = self.path.as_ref().parent() {
      vec![Resource::new("dir", parent.to_str().unwrap())]
    } else {
      vec![]
    }
  }

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

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

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

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