// Copyright 2017-2019 Parity Technologies (UK) Ltd.
// This file is part of Substrate.

// Substrate 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.

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

//! Chain utilities.

use crate::error;
use chain_spec::{ChainSpec, RuntimeGenesis, Extension};

/// Defines the logic for an operation exporting blocks within a range.
#[macro_export]
/// Export blocks
macro_rules! export_blocks {
($client:ident, $exit:ident, $output:ident, $from:ident, $to:ident, $json:ident) => {{
	let mut block = $from;

	let last = match $to {
		Some(v) if v.is_zero() => One::one(),
		Some(v) => v,
		None => $client.info().chain.best_number,
	};

	if last < block {
		return Err("Invalid block range specified".into());
	}

	let (exit_send, exit_recv) = std::sync::mpsc::channel();
	std::thread::spawn(move || {
		let _ = $exit.wait();
		let _ = exit_send.send(());
	});
	info!("Exporting blocks from #{} to #{}", block, last);
	if !$json {
		let last_: u64 = last.saturated_into::<u64>();
		let block_: u64 = block.saturated_into::<u64>();
		let len: u64 = last_ - block_ + 1;
		$output.write_all(&len.encode())?;
	}

	loop {
		if exit_recv.try_recv().is_ok() {
			break;
		}
		match $client.block(&BlockId::number(block))? {
			Some(block) => {
				if $json {
					serde_json::to_writer(&mut $output, &block)
						.map_err(|e| format!("Error writing JSON: {}", e))?;
				} else {
					$output.write_all(&block.encode())?;
				}
			},
			None => break,
		}
		if (block % 10000.into()).is_zero() {
			info!("#{}", block);
		}
		if block == last {
			break;
		}
		block += One::one();
	}
	Ok(())
}}
}

/// Defines the logic for an operation importing blocks from some known import.
#[macro_export]
/// Import blocks
macro_rules! import_blocks {
($block:ty, $client:ident, $queue:ident, $exit:ident, $input:ident) => {{
	use consensus_common::import_queue::{IncomingBlock, Link, BlockImportError, BlockImportResult};
	use consensus_common::BlockOrigin;
	use network::message;
	use sr_primitives::generic::SignedBlock;
	use sr_primitives::traits::Block;
	use futures03::TryFutureExt as _;

	struct WaitLink {
		imported_blocks: u64,
		has_error: bool,
	}

	impl WaitLink {
		fn new() -> WaitLink {
			WaitLink {
				imported_blocks: 0,
				has_error: false,
			}
		}
	}

	impl<B: Block> Link<B> for WaitLink {
		fn blocks_processed(
			&mut self,
			imported: usize,
			_count: usize,
			results: Vec<(Result<BlockImportResult<NumberFor<B>>, BlockImportError>, B::Hash)>
		) {
			self.imported_blocks += imported as u64;

			for result in results {
				if let (Err(err), hash) = result {
					warn!("There was an error importing block with hash {:?}: {:?}", hash, err);
					self.has_error = true;
					break;
				}
			}
		}
	}

	let (exit_send, exit_recv) = std::sync::mpsc::channel();
	std::thread::spawn(move || {
		let _ = $exit.wait();
		let _ = exit_send.send(());
	});

	let mut io_reader_input = IoReader($input);
	let count: u64 = Decode::decode(&mut io_reader_input)
		.map_err(|e| format!("Error reading file: {}", e))?;
	info!("Importing {} blocks", count);
	let mut block_count = 0;
	for b in 0 .. count {
		if exit_recv.try_recv().is_ok() {
			break;
		}
		match SignedBlock::<$block>::decode(&mut io_reader_input) {
			Ok(signed) => {
				let (header, extrinsics) = signed.block.deconstruct();
				let hash = header.hash();
				let block  = message::BlockData::<$block> {
					hash,
					justification: signed.justification,
					header: Some(header),
					body: Some(extrinsics),
					receipt: None,
					message_queue: None
				};
				// import queue handles verification and importing it into the client
				$queue.import_blocks(BlockOrigin::File, vec![
					IncomingBlock::<$block> {
						hash: block.hash,
						header: block.header,
						body: block.body,
						justification: block.justification,
						origin: None,
					}
				]);
			}
			Err(e) => {
				warn!("Error reading block data at {}: {}", b, e);
				break;
			}
		}

		block_count = b;
		if b % 1000 == 0 && b != 0 {
			info!("#{} blocks were added to the queue", b);
		}
	}

	let mut link = WaitLink::new();
	Ok(futures::future::poll_fn(move || {
		if exit_recv.try_recv().is_ok() {
			return Ok(Async::Ready(()));
		}

		let blocks_before = link.imported_blocks;
		let _ = futures03::future::poll_fn(|cx| {
			$queue.poll_actions(cx, &mut link);
			std::task::Poll::Pending::<Result<(), ()>>
		}).compat().poll();
		if link.has_error {
			info!(
				"Stopping after #{} blocks because of an error",
				link.imported_blocks,
			);
			return Ok(Async::Ready(()));
		}
		if link.imported_blocks / 1000 != blocks_before / 1000 {
			info!(
				"#{} blocks were imported (#{} left)",
				link.imported_blocks,
				count - link.imported_blocks
			);
		}
		if link.imported_blocks >= count {
			info!("Imported {} blocks. Best: #{}", block_count, $client.info().chain.best_number);
			Ok(Async::Ready(()))
		} else {
			Ok(Async::NotReady)
		}
	}))
}}
}

/// Revert the chain some number of blocks.
#[macro_export]
macro_rules! revert_chain {
($client:ident, $blocks:ident) => {{
	let reverted = $client.revert($blocks)?;
	let info = $client.info().chain;

	if reverted.is_zero() {
		info!("There aren't any non-finalized blocks to revert.");
	} else {
		info!("Reverted {} blocks. Best: #{} ({})", reverted, info.best_number, info.best_hash);
	}
	Ok(())
}}
}

/// Build a chain spec json
pub fn build_spec<G, E>(spec: ChainSpec<G, E>, raw: bool) -> error::Result<String> where
	G: RuntimeGenesis,
	E: Extension,
{
	Ok(spec.to_json(raw)?)
}