// 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 crypto::{
    self, pbkdf2,
    publickey::{Address, KeyPair, Secret},
    Keccak256,
};
use ethkey::Password;
use json;
use std::{fs, num::NonZeroU32, path::Path};
use Error;

/// Pre-sale wallet.
pub struct PresaleWallet {
    iv: [u8; 16],
    ciphertext: Vec<u8>,
    address: Address,
}

impl From<json::PresaleWallet> for PresaleWallet {
    fn from(wallet: json::PresaleWallet) -> Self {
        let mut iv = [0u8; 16];
        iv.copy_from_slice(&wallet.encseed[..16]);

        let mut ciphertext = vec![];
        ciphertext.extend_from_slice(&wallet.encseed[16..]);

        PresaleWallet {
            iv: iv,
            ciphertext: ciphertext,
            address: Address::from(wallet.address),
        }
    }
}

impl PresaleWallet {
    /// Open a pre-sale wallet.
    pub fn open<P>(path: P) -> Result<Self, Error>
    where
        P: AsRef<Path>,
    {
        let file = fs::File::open(path)?;
        let presale =
            json::PresaleWallet::load(file).map_err(|e| Error::InvalidKeyFile(format!("{}", e)))?;
        Ok(PresaleWallet::from(presale))
    }

    /// Decrypt the wallet.
    pub fn decrypt(&self, password: &Password) -> Result<KeyPair, Error> {
        let mut derived_key = [0u8; 32];
        let salt = pbkdf2::Salt(password.as_bytes());
        let sec = pbkdf2::Secret(password.as_bytes());
        let iter = NonZeroU32::new(2000).expect("2000 > 0; qed");
        pbkdf2::sha256(iter.get(), salt, sec, &mut derived_key);

        let mut key = vec![0; self.ciphertext.len()];
        let len =
            crypto::aes::decrypt_128_cbc(&derived_key[0..16], &self.iv, &self.ciphertext, &mut key)
                .map_err(|_| Error::InvalidPassword)?;
        let unpadded = &key[..len];

        let secret = Secret::import_key(&unpadded.keccak256())?;
        if let Ok(kp) = KeyPair::from_secret(secret) {
            if kp.address() == self.address {
                return Ok(kp);
            }
        }

        Err(Error::InvalidPassword)
    }
}

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

    #[test]
    fn test() {
        let json = r#"
		{
			"encseed": "137103c28caeebbcea5d7f95edb97a289ded151b72159137cb7b2671f394f54cff8c121589dcb373e267225547b3c71cbdb54f6e48ec85cd549f96cf0dedb3bc0a9ac6c79b9c426c5878ca2c9d06ff42a23cb648312fc32ba83649de0928e066",
			"ethaddr": "ede84640d1a1d3e06902048e67aa7db8d52c2ce1",
			"email": "123@gmail.com",
			"btcaddr": "1JvqEc6WLhg6GnyrLBe2ztPAU28KRfuseH"
		} "#;

        let wallet = json::PresaleWallet::load(json.as_bytes()).unwrap();
        let wallet = PresaleWallet::from(wallet);
        assert!(wallet.decrypt(&"123".into()).is_ok());
        assert!(wallet.decrypt(&"124".into()).is_err());
    }
}