// Copyright 2015, 2016 Ethcore (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/>.

#![warn(missing_docs)]
#![cfg_attr(feature="dev", feature(plugin))]
#![cfg_attr(feature="dev", plugin(clippy))]
// Keeps consistency (all lines with `.clone()`) and helpful when changing ref to non-ref.
#![cfg_attr(feature="dev", allow(clone_on_copy))]
// In most cases it expresses function flow better
#![cfg_attr(feature="dev", allow(if_not_else))]

//! Blockchain sync module
//! Implements ethereum protocol version 63 as specified here:
//! https://github.com/ethereum/wiki/wiki/Ethereum-Wire-Protocol
//!
//! Usage example:
//!
//! ```rust
//! extern crate ethcore_util as util;
//! extern crate ethcore;
//! extern crate ethsync;
//! use std::env;
//! use std::sync::Arc;
//! use util::network::{NetworkService, NetworkConfiguration};
//! use ethcore::client::{Client, ClientConfig};
//! use ethsync::{EthSync, SyncConfig};
//! use ethcore::ethereum;
//! use ethcore::miner::{GasPricer, Miner};
//!
//! fn main() {
//! 	let mut service = NetworkService::new(NetworkConfiguration::new()).unwrap();
//! 	service.start().unwrap();
//! 	let dir = env::temp_dir();
//! 	let miner = Miner::new(
//! 		Default::default(),
//! 		GasPricer::new_fixed(20_000_000_000u64.into()),
//! 		ethereum::new_frontier(),
//! 		None
//! 	);
//! 	let client = Client::new(
//!			ClientConfig::default(),
//!			ethereum::new_frontier(),
//!			&dir,
//!			miner,
//!			service.io().channel()
//!		).unwrap();
//! 	let sync = EthSync::new(SyncConfig::default(), client);
//! 	EthSync::register(&mut service, sync);
//! }
//! ```

#[macro_use]
extern crate log;
#[macro_use]
extern crate ethcore_util as util;
extern crate ethcore;
extern crate env_logger;
extern crate time;
extern crate rand;
#[macro_use]
extern crate heapsize;

use std::ops::*;
use std::sync::*;
use util::network::{NetworkProtocolHandler, NetworkService, NetworkContext, PeerId};
use util::{TimerToken, U256, RwLockable};
use ethcore::client::Client;
use ethcore::service::{SyncMessage, NetSyncMessage};
use io::NetSyncIo;
use util::io::IoChannel;
use util::{NetworkIoMessage, NetworkError};
use chain::ChainSync;

mod chain;
mod blocks;
mod io;

#[cfg(test)]
mod tests;

/// Sync configuration
pub struct SyncConfig {
	/// Max blocks to download ahead
	pub max_download_ahead_blocks: usize,
	/// Network ID
	pub network_id: U256,
}

impl Default for SyncConfig {
	fn default() -> SyncConfig {
		SyncConfig {
			max_download_ahead_blocks: 20000,
			network_id: U256::from(1),
		}
	}
}

/// Current sync status
pub trait SyncProvider: Send + Sync {
	/// Get sync status
	fn status(&self) -> SyncStatus;
	/// Start the network
	fn start_network(&self);
	/// Stop the network
	fn stop_network(&self);
}

/// Ethereum network protocol handler
pub struct EthSync {
	/// Shared blockchain client. TODO: this should evetually become an IPC endpoint
	chain: Arc<Client>,
	/// Sync strategy
	sync: RwLock<ChainSync>,
	/// IO communication chnnel.
	io_channel: RwLock<IoChannel<NetSyncMessage>>,
}

pub use self::chain::{SyncStatus, SyncState};

impl EthSync {
	/// Creates and register protocol with the network service
	pub fn new(config: SyncConfig, chain: Arc<Client>) -> Arc<EthSync> {
		let sync = ChainSync::new(config, chain.deref());
		Arc::new(EthSync {
			chain: chain,
			sync: RwLock::new(sync),
			io_channel: RwLock::new(IoChannel::disconnected()),
		})
	}

	/// Register protocol with the network service
	pub fn register(service: &NetworkService<SyncMessage>, sync: Arc<EthSync>) -> Result<(), NetworkError> {
		service.register_protocol(sync.clone(), "eth", &[62u8, 63u8])
	}

	/// Stop sync
	pub fn stop(&mut self, io: &mut NetworkContext<SyncMessage>) {
		self.sync.unwrapped_write().abort(&mut NetSyncIo::new(io, self.chain.deref()));
	}

	/// Restart sync
	pub fn restart(&mut self, io: &mut NetworkContext<SyncMessage>) {
		self.sync.unwrapped_write().restart(&mut NetSyncIo::new(io, self.chain.deref()));
	}
}

impl SyncProvider for EthSync {
	/// Get sync status
	fn status(&self) -> SyncStatus {
		self.sync.unwrapped_read().status()
	}

	fn start_network(&self) {
		self.io_channel.unwrapped_read().send(NetworkIoMessage::User(SyncMessage::StartNetwork))
			.unwrap_or_else(|e| warn!("Error sending IO notification: {:?}", e));
	}

	fn stop_network(&self) {
		self.io_channel.unwrapped_read().send(NetworkIoMessage::User(SyncMessage::StopNetwork))
			.unwrap_or_else(|e| warn!("Error sending IO notification: {:?}", e));
	}
}

impl NetworkProtocolHandler<SyncMessage> for EthSync {
	fn initialize(&self, io: &NetworkContext<SyncMessage>) {
		io.register_timer(0, 1000).expect("Error registering sync timer");
		*self.io_channel.unwrapped_write() = io.io_channel();
	}

	fn read(&self, io: &NetworkContext<SyncMessage>, peer: &PeerId, packet_id: u8, data: &[u8]) {
		ChainSync::dispatch_packet(&self.sync, &mut NetSyncIo::new(io, self.chain.deref()) , *peer, packet_id, data);
	}

	fn connected(&self, io: &NetworkContext<SyncMessage>, peer: &PeerId) {
		self.sync.unwrapped_write().on_peer_connected(&mut NetSyncIo::new(io, self.chain.deref()), *peer);
	}

	fn disconnected(&self, io: &NetworkContext<SyncMessage>, peer: &PeerId) {
		self.sync.unwrapped_write().on_peer_aborting(&mut NetSyncIo::new(io, self.chain.deref()), *peer);
	}

	fn timeout(&self, io: &NetworkContext<SyncMessage>, _timer: TimerToken) {
		self.sync.unwrapped_write().maintain_peers(&mut NetSyncIo::new(io, self.chain.deref()));
		self.sync.unwrapped_write().maintain_sync(&mut NetSyncIo::new(io, self.chain.deref()));
	}

	#[cfg_attr(feature="dev", allow(single_match))]
	fn message(&self, io: &NetworkContext<SyncMessage>, message: &SyncMessage) {
		match *message {
			SyncMessage::NewChainBlocks { ref imported, ref invalid, ref enacted, ref retracted, ref sealed } => {
				let mut sync_io = NetSyncIo::new(io, self.chain.deref());
				self.sync.unwrapped_write().chain_new_blocks(&mut sync_io, imported, invalid, enacted, retracted, sealed);
			},
			_ => {/* Ignore other messages */},
		}
	}
}