// Copyright 2015-2017 Parity Technologies (UK) Ltd.
// This file is part of Parity.

// Parity is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// Parity is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with Parity.  If not, see <http://www.gnu.org/licenses/>.

//! Random path

use std::path::*;
use std::fs;
use std::env;
use std::ops::{Deref, DerefMut};
use rand::random;

pub struct RandomTempPath {
	path: PathBuf,
	pub panic_on_drop_failure: bool,
}

pub fn random_filename() -> String {
	random_str(8)
}

pub fn random_str(len: usize) -> String {
	(0..len).map(|_| ((random::<f32>() * 26.0) as u8 + 97) as char).collect()
}

impl RandomTempPath {
	pub fn new() -> RandomTempPath {
		let mut dir = env::temp_dir();
		dir.push(random_filename());
		RandomTempPath {
			path: dir.clone(),
			panic_on_drop_failure: true,
		}
	}

	pub fn create_dir() -> RandomTempPath {
		let mut dir = env::temp_dir();
		dir.push(random_filename());
		fs::create_dir_all(dir.as_path()).unwrap();
		RandomTempPath {
			path: dir.clone(),
			panic_on_drop_failure: true,
		}
	}

	pub fn as_path(&self) -> &PathBuf {
		&self.path
	}

	pub fn as_str(&self) -> &str {
		self.path.to_str().unwrap()
	}

	pub fn new_in(&self, name: &str) -> String {
		let mut path = self.path.clone();
		path.push(name);
		path.to_str().unwrap().to_owned()
	}
}

impl AsRef<Path> for RandomTempPath {
	fn as_ref(&self) -> &Path {
		self.as_path()
	}
}
impl Deref for RandomTempPath {
	type Target = Path;
	fn deref(&self) -> &Self::Target {
		self.as_path()
	}
}

impl Drop for RandomTempPath {
	fn drop(&mut self) {
		if let Err(_) = fs::remove_dir_all(&self) {
			if let Err(e) = fs::remove_file(&self) {
				if self.panic_on_drop_failure {
					panic!("Failed to remove temp directory. Here's what prevented this from happening:  ({})", e);
				}
			}
		}
	}
}

pub struct GuardedTempResult<T> {
	pub result: Option<T>,
	pub _temp: RandomTempPath,
}

impl<T> GuardedTempResult<T> {
    pub fn reference(&self) -> &T {
        self.result.as_ref().unwrap()
    }

    pub fn reference_mut(&mut self) -> &mut T {
    	self.result.as_mut().unwrap()
    }

	pub fn take(&mut self) -> T {
		self.result.take().unwrap()
	}
}

impl<T> Deref for GuardedTempResult<T> {
	type Target = T;

	fn deref(&self) -> &T { self.result.as_ref().unwrap() }
}

impl<T> DerefMut for GuardedTempResult<T> {
	fn deref_mut(&mut self) -> &mut T { self.result.as_mut().unwrap() }
}

#[test]
fn creates_dir() {
	let temp = RandomTempPath::create_dir();
	assert!(fs::metadata(temp.as_path()).unwrap().is_dir());
}

#[test]
fn destroys_dir() {
	let path_buf = {
		let temp = RandomTempPath::create_dir();
		assert!(fs::metadata(temp.as_path()).unwrap().is_dir());
		let path_buf = temp.as_path().to_path_buf();
		path_buf
	};

	assert!(fs::metadata(&path_buf).is_err());
}

#[test]
fn provides_random() {
	let temp = RandomTempPath::create_dir();
	assert!(temp.as_path().to_str().is_some());
}