// Copyright 2017 Parity Technologies (UK) Ltd.
// This file is part of Polkadot.

// Polkadot 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.

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

//! Polkadot CLI library.

#![warn(missing_docs)]
#![warn(unused_extern_crates)]

extern crate futures;
extern crate tokio;

extern crate substrate_cli as cli;
extern crate polkadot_service as service;
extern crate exit_future;

#[macro_use]
extern crate log;

mod chain_spec;

pub use cli::error;

use chain_spec::ChainSpec;

use futures::Future;
use tokio::runtime::Runtime;
pub use service::{Components as ServiceComponents, Service, CustomConfiguration};
pub use cli::{VersionInfo, IntoExit};

fn load_spec(id: &str) -> Result<Option<service::ChainSpec>, String> {
	Ok(match ChainSpec::from(id) {
		Some(spec) => Some(spec.load()?),
		None => None,
	})
}

/// Additional worker making use of the node, to run asynchronously before shutdown.
///
/// This will be invoked with the service and spawn a future that resolves
/// when complete.
pub trait Worker: IntoExit {
	/// A future that resolves when the work is done or the node should exit.
	/// This will be run on a tokio runtime.
	type Work: Future<Item=(),Error=()> + Send + 'static;

	/// Return configuration for the polkadot node.
	// TODO: make this the full configuration, so embedded nodes don't need
	// string CLI args
	fn configuration(&self) -> service::CustomConfiguration { Default::default() }

	/// Do work and schedule exit.
	fn work<C: service::Components>(self, service: &service::Service<C>) -> Self::Work;
}

/// Parse command line arguments into service configuration.
///
/// IANA unassigned port ranges that we could use:
/// 6717-6766		Unassigned
/// 8504-8553		Unassigned
/// 9556-9591		Unassigned
/// 9803-9874		Unassigned
/// 9926-9949		Unassigned
pub fn run<I, T, W>(args: I, worker: W, version: cli::VersionInfo) -> error::Result<()> where
	I: IntoIterator<Item = T>,
	T: Into<std::ffi::OsString> + Clone,
	W: Worker,
{

	match cli::prepare_execution::<service::Factory, _, _, _, _>(args, worker, version, load_spec, "parity-polkadot")? {
		cli::Action::ExecutedInternally => (),
		cli::Action::RunService((mut config, worker)) => {
			info!("Parity ·:· Polkadot");
			info!("  version {}", config.full_version());
			info!("  by Parity Technologies, 2017, 2018");
			info!("Chain specification: {}", config.chain_spec.name());
			info!("Node name: {}", config.name);
			info!("Roles: {:?}", config.roles);
			config.custom = worker.configuration();
			let mut runtime = Runtime::new()?;
			let executor = runtime.executor();
			match config.roles == service::Roles::LIGHT {
				true => run_until_exit(&mut runtime, service::new_light(config, executor)?, worker)?,
				false => run_until_exit(&mut runtime, service::new_full(config, executor)?, worker)?,
			}
			// TODO: hard exit if this stalls?
			runtime.shutdown_on_idle().wait().expect("failed to shut down event loop");
		}
	}
	Ok(())
}
fn run_until_exit<C, W>(
	runtime: &mut Runtime,
	service: service::Service<C>,
	worker: W,
) -> error::Result<()>
	where
		C: service::Components,
		W: Worker,
{
	let (exit_send, exit) = exit_future::signal();

	let executor = runtime.executor();
	cli::informant::start(&service, exit.clone(), executor.clone());

	let _ = runtime.block_on(worker.work(&service));
	exit_send.fire();
	Ok(())
}
