// Copyright 2015-2020 Parity Technologies (UK) Ltd.
// This file is part of OpenEthereum.

// OpenEthereum 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.

// OpenEthereum 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 OpenEthereum.  If not, see <http://www.gnu.org/licenses/>.

use super::{Generator, KeyPair, Secret};
use keccak::Keccak256;
use parity_wordlist;

/// Simple brainwallet.
pub struct Brain(String);

impl Brain {
    pub fn new(s: String) -> Self {
        Brain(s)
    }

    pub fn validate_phrase(phrase: &str, expected_words: usize) -> Result<(), ::WordlistError> {
        parity_wordlist::validate_phrase(phrase, expected_words)
    }
}

impl Generator for Brain {
    type Error = ::Void;

    fn generate(&mut self) -> Result<KeyPair, Self::Error> {
        let seed = self.0.clone();
        let mut secret = seed.into_bytes().keccak256();

        let mut i = 0;
        loop {
            secret = secret.keccak256();

            match i > 16384 {
                false => i += 1,
                true => {
                    if let Ok(pair) =
                        Secret::from_unsafe_slice(&secret).and_then(KeyPair::from_secret)
                    {
                        if pair.address()[0] == 0 {
                            trace!("Testing: {}, got: {:?}", self.0, pair.address());
                            return Ok(pair);
                        }
                    }
                }
            }
        }
    }
}

#[cfg(test)]
mod tests {
    use Brain;
    use Generator;

    #[test]
    fn test_brain() {
        let words = "this is sparta!".to_owned();
        let first_keypair = Brain::new(words.clone()).generate().unwrap();
        let second_keypair = Brain::new(words.clone()).generate().unwrap();
        assert_eq!(first_keypair.secret(), second_keypair.secret());
    }
}