// Copyright 2015-2018 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/>.

extern crate docopt;
extern crate env_logger;
extern crate ethkey;
extern crate panic_hook;
extern crate parity_wordlist;
extern crate rustc_hex;
extern crate serde;
extern crate threadpool;

#[macro_use]
extern crate serde_derive;

use std::num::ParseIntError;
use std::{env, fmt, process, io, sync};

use docopt::Docopt;
use ethkey::{KeyPair, Random, Brain, BrainPrefix, Prefix, Error as EthkeyError, Generator, sign, verify_public, verify_address, brain_recover};
use rustc_hex::{FromHex, FromHexError};

const USAGE: &'static str = r#"
Ethereum keys generator.
  Copyright 2016, 2017 Parity Technologies (UK) Ltd

Usage:
    ethkey info <secret-or-phrase> [options]
    ethkey generate random [options]
    ethkey generate prefix <prefix> [options]
    ethkey sign <secret> <message>
    ethkey verify public <public> <signature> <message>
    ethkey verify address <address> <signature> <message>
    ethkey recover <address> <known-phrase>
    ethkey [-h | --help]

Options:
    -h, --help         Display this message and exit.
    -s, --secret       Display only the secret.
    -p, --public       Display only the public.
    -a, --address      Display only the address.
    -b, --brain        Use parity brain wallet algorithm.

Commands:
    info               Display public and address of the secret.
    generate random    Generates new random ethereum key.
    generate prefix    Random generation, but address must start with a prefix.
    sign               Sign message using secret.
    verify             Verify signer of the signature.
    recover            Try to find brain phrase matching given address from partial phrase.
"#;

#[derive(Debug, Deserialize)]
struct Args {
	cmd_info: bool,
	cmd_generate: bool,
	cmd_random: bool,
	cmd_prefix: bool,
	cmd_sign: bool,
	cmd_verify: bool,
	cmd_public: bool,
	cmd_address: bool,
	cmd_recover: bool,
	arg_prefix: String,
	arg_secret: String,
	arg_secret_or_phrase: String,
	arg_known_phrase: String,
	arg_message: String,
	arg_public: String,
	arg_address: String,
	arg_signature: String,
	flag_secret: bool,
	flag_public: bool,
	flag_address: bool,
	flag_brain: bool,
}

#[derive(Debug)]
enum Error {
	Ethkey(EthkeyError),
	FromHex(FromHexError),
	ParseInt(ParseIntError),
	Docopt(docopt::Error),
	Io(io::Error),
}

impl From<EthkeyError> for Error {
	fn from(err: EthkeyError) -> Self {
		Error::Ethkey(err)
	}
}

impl From<FromHexError> for Error {
	fn from(err: FromHexError) -> Self {
		Error::FromHex(err)
	}
}

impl From<ParseIntError> for Error {
	fn from(err: ParseIntError) -> Self {
		Error::ParseInt(err)
	}
}

impl From<docopt::Error> for Error {
	fn from(err: docopt::Error) -> Self {
		Error::Docopt(err)
	}
}

impl From<io::Error> for Error {
	fn from(err: io::Error) -> Self {
		Error::Io(err)
	}
}

impl fmt::Display for Error {
	fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
		match *self {
			Error::Ethkey(ref e) => write!(f, "{}", e),
			Error::FromHex(ref e) => write!(f, "{}", e),
			Error::ParseInt(ref e) => write!(f, "{}", e),
			Error::Docopt(ref e) => write!(f, "{}", e),
			Error::Io(ref e) => write!(f, "{}", e),
		}
	}
}

enum DisplayMode {
	KeyPair,
	Secret,
	Public,
	Address,
}

impl DisplayMode {
	fn new(args: &Args) -> Self {
		if args.flag_secret {
			DisplayMode::Secret
		} else if args.flag_public {
			DisplayMode::Public
		} else if args.flag_address {
			DisplayMode::Address
		} else {
			DisplayMode::KeyPair
		}
	}
}

fn main() {
	panic_hook::set();
	env_logger::init().expect("Logger initialized only once.");

	match execute(env::args()) {
		Ok(ok) => println!("{}", ok),
		Err(Error::Docopt(ref e)) => e.exit(),
		Err(err) => {
			println!("{}", err);
			process::exit(1);
		}
	}
}

fn display(result: (KeyPair, Option<String>), mode: DisplayMode) -> String {
	let keypair = result.0;
	match mode {
		DisplayMode::KeyPair => match result.1 {
			Some(extra_data) => format!("{}\n{}", extra_data, keypair),
			None => format!("{}", keypair)
		},
		DisplayMode::Secret => format!("{:x}", keypair.secret()),
		DisplayMode::Public => format!("{:x}", keypair.public()),
		DisplayMode::Address => format!("{:x}", keypair.address()),
	}
}

fn execute<S, I>(command: I) -> Result<String, Error> where I: IntoIterator<Item=S>, S: AsRef<str> {
	let args: Args = Docopt::new(USAGE)
		.and_then(|d| d.argv(command).deserialize())?;

	return if args.cmd_info {
		let display_mode = DisplayMode::new(&args);

		let result = if args.flag_brain {
			let phrase = args.arg_secret_or_phrase;
			let phrase_info = validate_phrase(&phrase);
			let keypair = Brain::new(phrase).generate().expect("Brain wallet generator is infallible; qed");
			(keypair, Some(phrase_info))
		} else {
			let secret = args.arg_secret_or_phrase.parse().map_err(|_| EthkeyError::InvalidSecret)?;
			(KeyPair::from_secret(secret)?, None)
		};
		Ok(display(result, display_mode))
	} else if args.cmd_generate {
		let display_mode = DisplayMode::new(&args);
		let result = if args.cmd_random {
			if args.flag_brain {
				let mut brain = BrainPrefix::new(vec![0], usize::max_value(), BRAIN_WORDS);
				let keypair = brain.generate()?;
				let phrase = format!("recovery phrase: {}", brain.phrase());
				(keypair, Some(phrase))
			} else {
				(Random.generate()?, None)
			}
		} else if args.cmd_prefix {
			let prefix = args.arg_prefix.from_hex()?;
			let brain = args.flag_brain;
			in_threads(move || {
				let iterations = 1024;
				let prefix = prefix.clone();
				move || {
					let prefix = prefix.clone();
					let res = if brain {
						let mut brain = BrainPrefix::new(prefix, iterations, BRAIN_WORDS);
						let result = brain.generate();
						let phrase = format!("recovery phrase: {}", brain.phrase());
						result.map(|keypair| (keypair, Some(phrase)))
					} else {
						let result = Prefix::new(prefix, iterations).generate();
						result.map(|res| (res, None))
					};

					Ok(res.map(Some).unwrap_or(None))
				}
			})?
		} else {
			return Ok(format!("{}", USAGE))
		};
		Ok(display(result, display_mode))
	} else if args.cmd_sign {
		let secret = args.arg_secret.parse().map_err(|_| EthkeyError::InvalidSecret)?;
		let message = args.arg_message.parse().map_err(|_| EthkeyError::InvalidMessage)?;
		let signature = sign(&secret, &message)?;
		Ok(format!("{}", signature))
	} else if args.cmd_verify {
		let signature = args.arg_signature.parse().map_err(|_| EthkeyError::InvalidSignature)?;
		let message = args.arg_message.parse().map_err(|_| EthkeyError::InvalidMessage)?;
		let ok = if args.cmd_public {
			let public = args.arg_public.parse().map_err(|_| EthkeyError::InvalidPublic)?;
			verify_public(&public, &signature, &message)?
		} else if args.cmd_address {
			let address = args.arg_address.parse().map_err(|_| EthkeyError::InvalidAddress)?;
			verify_address(&address, &signature, &message)?
		} else {
			return Ok(format!("{}", USAGE))
		};
		Ok(format!("{}", ok))
	} else if args.cmd_recover {
		let display_mode = DisplayMode::new(&args);
		let known_phrase = args.arg_known_phrase;
		let address = args.arg_address.parse().map_err(|_| EthkeyError::InvalidAddress)?;
		let (phrase, keypair) = in_threads(move || {
			let mut it = brain_recover::PhrasesIterator::from_known_phrase(&known_phrase, BRAIN_WORDS);
			move || {
				let mut i = 0;
				while let Some(phrase) = it.next() {
					i += 1;

					let keypair = Brain::new(phrase.clone()).generate().unwrap();
					if keypair.address() == address {
						return Ok(Some((phrase, keypair)))
					}

					if i >= 1024 {
						return Ok(None)
					}
				}

				Err(EthkeyError::Custom("Couldn't find any results.".into()))
			}
		})?;
		Ok(display((keypair, Some(phrase)), display_mode))
	} else {
		Ok(format!("{}", USAGE))
	}
}

const BRAIN_WORDS: usize = 12;

fn validate_phrase(phrase: &str) -> String {
	match Brain::validate_phrase(phrase, BRAIN_WORDS) {
		Ok(()) => format!("The recovery phrase looks correct.\n"),
		Err(err) => format!("The recover phrase was not generated by Parity: {}", err)
	}
}

fn in_threads<F, X, O>(prepare: F) -> Result<O, EthkeyError> where
	O: Send + 'static,
	X: Send + 'static,
	F: Fn() -> X,
	X: FnMut() -> Result<Option<O>, EthkeyError>,
{
	let pool = threadpool::Builder::new().build();

	let (tx, rx) = sync::mpsc::sync_channel(1);
	let is_done = sync::Arc::new(sync::atomic::AtomicBool::default());

	for _ in 0..pool.max_count() {
		let is_done = is_done.clone();
		let tx = tx.clone();
		let mut task = prepare();
		pool.execute(move || {
			loop {
				if is_done.load(sync::atomic::Ordering::SeqCst) {
					return;
				}

				let res = match task() {
					Ok(None) => continue,
					Ok(Some(v)) => Ok(v),
					Err(err) => Err(err),
				};

				// We are interested only in the first response.
				let _ = tx.send(res);
			}
		});
	}

	if let Ok(solution) = rx.recv() {
		is_done.store(true, sync::atomic::Ordering::SeqCst);
		return solution;
	}

	Err(EthkeyError::Custom("No results found.".into()))
}

#[cfg(test)]
mod tests {
	use super::execute;

	#[test]
	fn info() {
		let command = vec!["ethkey", "info", "17d08f5fe8c77af811caa0c9a187e668ce3b74a99acc3f6d976f075fa8e0be55"]
			.into_iter()
			.map(Into::into)
			.collect::<Vec<String>>();

		let expected =
"secret:  17d08f5fe8c77af811caa0c9a187e668ce3b74a99acc3f6d976f075fa8e0be55
public:  689268c0ff57a20cd299fa60d3fb374862aff565b20b5f1767906a99e6e09f3ff04ca2b2a5cd22f62941db103c0356df1a8ed20ce322cab2483db67685afd124
address: 26d1ec50b4e62c1d1a40d16e7cacc6a6580757d5".to_owned();
		assert_eq!(execute(command).unwrap(), expected);
	}

	#[test]
	fn brain() {
		let command = vec!["ethkey", "info", "--brain", "this is sparta"]
			.into_iter()
			.map(Into::into)
			.collect::<Vec<String>>();

		let expected =
"The recover phrase was not generated by Parity: The word 'this' does not come from the dictionary.

secret:  aa22b54c0cb43ee30a014afe5ef3664b1cde299feabca46cd3167a85a57c39f2
public:  c4c5398da6843632c123f543d714d2d2277716c11ff612b2a2f23c6bda4d6f0327c31cd58c55a9572c3cc141dade0c32747a13b7ef34c241b26c84adbb28fcf4
address: 006e27b6a72e1f34c626762f3c4761547aff1421".to_owned();
		assert_eq!(execute(command).unwrap(), expected);
	}

	#[test]
	fn secret() {
		let command = vec!["ethkey", "info", "--brain", "this is sparta", "--secret"]
			.into_iter()
			.map(Into::into)
			.collect::<Vec<String>>();

		let expected = "aa22b54c0cb43ee30a014afe5ef3664b1cde299feabca46cd3167a85a57c39f2".to_owned();
		assert_eq!(execute(command).unwrap(), expected);
	}

	#[test]
	fn public() {
		let command = vec!["ethkey", "info", "--brain", "this is sparta", "--public"]
			.into_iter()
			.map(Into::into)
			.collect::<Vec<String>>();

		let expected = "c4c5398da6843632c123f543d714d2d2277716c11ff612b2a2f23c6bda4d6f0327c31cd58c55a9572c3cc141dade0c32747a13b7ef34c241b26c84adbb28fcf4".to_owned();
		assert_eq!(execute(command).unwrap(), expected);
	}

	#[test]
	fn address() {
		let command = vec!["ethkey", "info", "-b", "this is sparta", "--address"]
			.into_iter()
			.map(Into::into)
			.collect::<Vec<String>>();

		let expected = "006e27b6a72e1f34c626762f3c4761547aff1421".to_owned();
		assert_eq!(execute(command).unwrap(), expected);
	}

	#[test]
	fn sign() {
		let command = vec!["ethkey", "sign", "17d08f5fe8c77af811caa0c9a187e668ce3b74a99acc3f6d976f075fa8e0be55", "bd50b7370c3f96733b31744c6c45079e7ae6c8d299613246d28ebcef507ec987"]
			.into_iter()
			.map(Into::into)
			.collect::<Vec<String>>();

		let expected = "c1878cf60417151c766a712653d26ef350c8c75393458b7a9be715f053215af63dfd3b02c2ae65a8677917a8efa3172acb71cb90196e42106953ea0363c5aaf200".to_owned();
		assert_eq!(execute(command).unwrap(), expected);
	}

	#[test]
	fn verify_valid_public() {
		let command = vec!["ethkey", "verify", "public", "689268c0ff57a20cd299fa60d3fb374862aff565b20b5f1767906a99e6e09f3ff04ca2b2a5cd22f62941db103c0356df1a8ed20ce322cab2483db67685afd124", "c1878cf60417151c766a712653d26ef350c8c75393458b7a9be715f053215af63dfd3b02c2ae65a8677917a8efa3172acb71cb90196e42106953ea0363c5aaf200", "bd50b7370c3f96733b31744c6c45079e7ae6c8d299613246d28ebcef507ec987"]
			.into_iter()
			.map(Into::into)
			.collect::<Vec<String>>();

		let expected = "true".to_owned();
		assert_eq!(execute(command).unwrap(), expected);
	}

	#[test]
	fn verify_valid_address() {
		let command = vec!["ethkey", "verify", "address", "26d1ec50b4e62c1d1a40d16e7cacc6a6580757d5", "c1878cf60417151c766a712653d26ef350c8c75393458b7a9be715f053215af63dfd3b02c2ae65a8677917a8efa3172acb71cb90196e42106953ea0363c5aaf200", "bd50b7370c3f96733b31744c6c45079e7ae6c8d299613246d28ebcef507ec987"]
			.into_iter()
			.map(Into::into)
			.collect::<Vec<String>>();

		let expected = "true".to_owned();
		assert_eq!(execute(command).unwrap(), expected);
	}

	#[test]
	fn verify_invalid() {
		let command = vec!["ethkey", "verify", "public", "689268c0ff57a20cd299fa60d3fb374862aff565b20b5f1767906a99e6e09f3ff04ca2b2a5cd22f62941db103c0356df1a8ed20ce322cab2483db67685afd124", "c1878cf60417151c766a712653d26ef350c8c75393458b7a9be715f053215af63dfd3b02c2ae65a8677917a8efa3172acb71cb90196e42106953ea0363c5aaf200", "bd50b7370c3f96733b31744c6c45079e7ae6c8d299613246d28ebcef507ec986"]
			.into_iter()
			.map(Into::into)
			.collect::<Vec<String>>();

		let expected = "false".to_owned();
		assert_eq!(execute(command).unwrap(), expected);
	}
}