// 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/>.

use std::collections::HashMap;
use parking_lot::RwLock;
use itertools::Itertools;
use ethkey::Address;

use {SafeAccount, Error};
use super::KeyDirectory;

#[derive(Default)]
pub struct MemoryDirectory {
	accounts: RwLock<HashMap<Address, Vec<SafeAccount>>>,
}

impl KeyDirectory for MemoryDirectory {
	fn load(&self) -> Result<Vec<SafeAccount>, Error> {
		Ok(self.accounts.read().values().cloned().flatten().collect())
	}

	fn update(&self, account: SafeAccount) -> Result<SafeAccount, Error> {
		let mut lock = self.accounts.write();
		let mut accounts = lock.entry(account.address.clone()).or_insert_with(Vec::new);
		// If the filename is the same we just need to replace the entry
		accounts.retain(|acc| acc.filename != account.filename);
		accounts.push(account.clone());
		Ok(account)
	}

	fn insert(&self, account: SafeAccount) -> Result<SafeAccount, Error> {
		let mut lock = self.accounts.write();
		let mut accounts = lock.entry(account.address.clone()).or_insert_with(Vec::new);
		accounts.push(account.clone());
		Ok(account)
	}

	fn remove(&self, account: &SafeAccount) -> Result<(), Error> {
		let mut accounts = self.accounts.write();
		let is_empty = if let Some(mut accounts) = accounts.get_mut(&account.address) {
			if let Some(position) = accounts.iter().position(|acc| acc == account) {
				accounts.remove(position);
			}
			accounts.is_empty()
		} else {
			false
		};
		if is_empty {
			accounts.remove(&account.address);
		}
		Ok(())
	}

	fn unique_repr(&self) -> Result<u64, Error> {
		let mut val = 0u64;
		let accounts = self.accounts.read();
		for acc in accounts.keys() { val = val ^ ::util::FixedHash::low_u64(acc) }
		Ok(val)
	}
}

