// 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/>.

use std::sync::Arc;

use dir::Directories;
use ethereum_types::Address;
use ethkey::Password;

use params::{SpecType, AccountsConfig};

#[cfg(not(feature = "accounts"))]
mod accounts {
	use super::*;

	/// Dummy AccountProvider
	pub struct AccountProvider;

	impl ::ethcore::miner::LocalAccounts for AccountProvider {
		fn is_local(&self, _address: &Address) -> bool {
			false
		}
	}

	pub fn prepare_account_provider(_spec: &SpecType, _dirs: &Directories, _data_dir: &str, _cfg: AccountsConfig, _passwords: &[Password]) -> Result<AccountProvider, String> {
		warn!("Note: Your instance of Parity Ethereum is running without account support. Some CLI options are ignored.");
		Ok(AccountProvider)
	}

	pub fn miner_local_accounts(_: Arc<AccountProvider>) -> AccountProvider {
		AccountProvider
	}

	pub fn miner_author(_spec: &SpecType, _dirs: &Directories, _account_provider: &Arc<AccountProvider>, _engine_signer: Address, _passwords: &[Password]) -> Result<Option<::ethcore::miner::Author>, String> {
		Ok(None)
	}

	pub fn private_tx_signer(_account_provider: Arc<AccountProvider>, _passwords: &[Password]) -> Result<Arc<::ethcore_private_tx::Signer>, String> {
		Ok(Arc::new(::ethcore_private_tx::DummySigner))
	}

	pub fn accounts_list(_account_provider: Arc<AccountProvider>) -> Arc<Fn() -> Vec<Address> + Send + Sync> {
		Arc::new(|| vec![])
	}
}

#[cfg(feature = "accounts")]
mod accounts {
	use super::*;
	use upgrade::upgrade_key_location;
	use ethereum_types::H160;
	use std::str::FromStr;

	pub use accounts::AccountProvider;

	/// Pops along with error messages when a password is missing or invalid.
	const VERIFY_PASSWORD_HINT: &str = "Make sure valid password is present in files passed using `--password` or in the configuration file.";

	/// Initialize account provider
	pub fn prepare_account_provider(spec: &SpecType, dirs: &Directories, data_dir: &str, cfg: AccountsConfig, passwords: &[Password]) -> Result<AccountProvider, String> {
		use ethstore::EthStore;
		use ethstore::accounts_dir::RootDiskDirectory;
		use accounts::AccountProviderSettings;

		let path = dirs.keys_path(data_dir);
		upgrade_key_location(&dirs.legacy_keys_path(cfg.testnet), &path);
		let dir = Box::new(RootDiskDirectory::create(&path).map_err(|e| format!("Could not open keys directory: {}", e))?);
		let account_settings = AccountProviderSettings {
			unlock_keep_secret: cfg.enable_fast_unlock,
			blacklisted_accounts: 	match *spec {
				SpecType::Morden | SpecType::Ropsten | SpecType::Kovan | SpecType::Sokol | SpecType::Dev => vec![],
				_ => vec![
					H160::from_str("00a329c0648769a73afac7f9381e08fb43dbea72").expect("the string is valid hex; qed"),
				],
			},
		};

		let ethstore = EthStore::open_with_iterations(dir, cfg.iterations).map_err(|e| format!("Could not open keys directory: {}", e))?;
		if cfg.refresh_time > 0 {
			ethstore.set_refresh_time(::std::time::Duration::from_secs(cfg.refresh_time));
		}
		let account_provider = AccountProvider::new(
			Box::new(ethstore),
			account_settings,
		);

		// Add development account if running dev chain:
		if let SpecType::Dev = *spec {
			insert_dev_account(&account_provider);
		}

		for a in cfg.unlocked_accounts {
			// Check if the account exists
			if !account_provider.has_account(a) {
				return Err(format!("Account {} not found for the current chain. {}", a, build_create_account_hint(spec, &dirs.keys)));
			}

			// Check if any passwords have been read from the password file(s)
			if passwords.is_empty() {
				return Err(format!("No password found to unlock account {}. {}", a, VERIFY_PASSWORD_HINT));
			}

			if !passwords.iter().any(|p| account_provider.unlock_account_permanently(a, (*p).clone()).is_ok()) {
				return Err(format!("No valid password to unlock account {}. {}", a, VERIFY_PASSWORD_HINT));
			}
		}

		Ok(account_provider)
	}

	pub struct LocalAccounts(Arc<AccountProvider>);
	impl ::ethcore::miner::LocalAccounts for LocalAccounts {
		fn is_local(&self, address: &Address) -> bool {
			self.0.has_account(*address)
		}
	}

	pub fn miner_local_accounts(account_provider: Arc<AccountProvider>) -> LocalAccounts {
		LocalAccounts(account_provider)
	}

	pub fn miner_author(spec: &SpecType, dirs: &Directories, account_provider: &Arc<AccountProvider>, engine_signer: Address, passwords: &[Password]) -> Result<Option<::ethcore::miner::Author>, String> {
		use engine::signer::EngineSigner;

		// Check if engine signer exists
		if !account_provider.has_account(engine_signer) {
			return Err(format!("Consensus signer account not found for the current chain. {}", build_create_account_hint(spec, &dirs.keys)));
		}

		// Check if any passwords have been read from the password file(s)
		if passwords.is_empty() {
			return Err(format!("No password found for the consensus signer {}. {}", engine_signer, VERIFY_PASSWORD_HINT));
		}

		let mut author = None;
		for password in passwords {
			let signer = parity_rpc::signer::EngineSigner::new(
				account_provider.clone(),
				engine_signer,
				password.clone(),
			);
			if signer.sign(Default::default()).is_ok() {
				author = Some(::ethcore::miner::Author::Sealer(Box::new(signer)));
			}
		}
		if author.is_none() {
			return Err(format!("No valid password for the consensus signer {}. {}", engine_signer, VERIFY_PASSWORD_HINT));
		}

		Ok(author)
	}


	mod private_tx {
		use super::*;
		use ethkey::{Signature, Message};
		use ethcore_private_tx::{Error};

		pub struct AccountSigner {
			pub accounts: Arc<AccountProvider>,
			pub passwords: Vec<Password>,
		}

		impl ::ethcore_private_tx::Signer for AccountSigner {
			fn decrypt(&self, account: Address, shared_mac: &[u8], payload: &[u8]) -> Result<Vec<u8>, Error> {
				let password = self.find_account_password(&account);
				Ok(self.accounts.decrypt(account, password, shared_mac, payload).map_err(|e| e.to_string())?)
			}

			fn sign(&self, account: Address, hash: Message) -> Result<Signature, Error> {
				let password = self.find_account_password(&account);
				Ok(self.accounts.sign(account, password, hash).map_err(|e| e.to_string())?)
			}
		}

		impl AccountSigner {
			/// Try to unlock account using stored password, return found password if any
			fn find_account_password(&self, account: &Address) -> Option<Password> {
				for password in &self.passwords {
					if let Ok(true) = self.accounts.test_password(account, password) {
						return Some(password.clone());
					}
				}
				None
			}
		}
	}

	pub fn private_tx_signer(accounts: Arc<AccountProvider>, passwords: &[Password]) -> Result<Arc<dyn (ethcore_private_tx::Signer)>, String> {
		Ok(Arc::new(self::private_tx::AccountSigner {
			accounts,
			passwords: passwords.to_vec(),
		}))
	}

	pub fn accounts_list(account_provider: Arc<AccountProvider>) -> Arc<dyn Fn() -> Vec<Address> + Send + Sync> {
		Arc::new(move || account_provider.accounts().unwrap_or_default())
	}

	fn insert_dev_account(account_provider: &AccountProvider) {
		let secret: ethkey::Secret = "4d5db4107d237df6a3d58ee5f70ae63d73d7658d4026f2eefd2f204c81682cb7".into();
		let dev_account = ethkey::KeyPair::from_secret(secret.clone()).expect("Valid secret produces valid key;qed");
		if !account_provider.has_account(dev_account.address()) {
			match account_provider.insert_account(secret, &Password::from(String::new())) {
				Err(e) => warn!("Unable to add development account: {}", e),
				Ok(address) => {
					let _ = account_provider.set_account_name(address.clone(), "Development Account".into());
					let _ = account_provider.set_account_meta(address, ::serde_json::to_string(&(vec![
						("description", "Never use this account outside of development chain!"),
						("passwordHint","Password is empty string"),
					].into_iter().collect::<::std::collections::HashMap<_,_>>())).expect("Serialization of hashmap does not fail."));
				},
			}
		}
	}

	// Construct an error `String` with an adaptive hint on how to create an account.
	fn build_create_account_hint(spec: &SpecType, keys: &str) -> String {
		format!("You can create an account via RPC, UI or `parity account new --chain {} --keys-path {}`.", spec, keys)
	}
}

pub use self::accounts::{
	AccountProvider,
	prepare_account_provider,
	miner_local_accounts,
	miner_author,
	private_tx_signer,
	accounts_list,
};