// 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/>.

//! PoW block chunker and rebuilder tests.

use devtools::RandomTempPath;
use error::Error;

use blockchain::generator::{ChainGenerator, ChainIterator, BlockFinalizer};
use blockchain::BlockChain;
use snapshot::{chunk_secondary, Error as SnapshotError, Progress, SnapshotComponents};
use snapshot::io::{PackedReader, PackedWriter, SnapshotReader, SnapshotWriter};

use util::{Mutex, snappy};
use util::kvdb::{self, KeyValueDB, DBTransaction};

use std::sync::Arc;
use std::sync::atomic::AtomicBool;

const SNAPSHOT_MODE: ::snapshot::PowSnapshot = ::snapshot::PowSnapshot { blocks: 30000, max_restore_blocks: 30000 };

fn chunk_and_restore(amount: u64) {
	let mut canon_chain = ChainGenerator::default();
	let mut finalizer = BlockFinalizer::default();
	let genesis = canon_chain.generate(&mut finalizer).unwrap();

	let engine = Arc::new(::engines::NullEngine::default());
	let new_path = RandomTempPath::create_dir();
	let mut snapshot_path = new_path.as_path().to_owned();
	snapshot_path.push("SNAP");

	let old_db = Arc::new(kvdb::in_memory(::db::NUM_COLUMNS.unwrap_or(0)));
	let bc = BlockChain::new(Default::default(), &genesis, old_db.clone());

	// build the blockchain.
	let mut batch = DBTransaction::new();
	for _ in 0..amount {
		let block = canon_chain.generate(&mut finalizer).unwrap();
		bc.insert_block(&mut batch, &block, vec![]);
		bc.commit();
	}

	old_db.write(batch).unwrap();

	let best_hash = bc.best_block_hash();

	// snapshot it.
	let writer = Mutex::new(PackedWriter::new(&snapshot_path).unwrap());
	let block_hashes = chunk_secondary(
		Box::new(SNAPSHOT_MODE),
		&bc,
		best_hash,
		&writer,
		&Progress::default()
	).unwrap();

	let manifest = ::snapshot::ManifestData {
		version: 2,
		state_hashes: Vec::new(),
		block_hashes: block_hashes,
		state_root: ::hash::KECCAK_NULL_RLP,
		block_number: amount,
		block_hash: best_hash,
	};

	writer.into_inner().finish(manifest.clone()).unwrap();

	// restore it.
	let new_db = Arc::new(kvdb::in_memory(::db::NUM_COLUMNS.unwrap_or(0)));
	let new_chain = BlockChain::new(Default::default(), &genesis, new_db.clone());
	let mut rebuilder = SNAPSHOT_MODE.rebuilder(new_chain, new_db.clone(), &manifest).unwrap();

	let reader = PackedReader::new(&snapshot_path).unwrap().unwrap();
	let flag = AtomicBool::new(true);
	for chunk_hash in &reader.manifest().block_hashes {
		let compressed = reader.chunk(*chunk_hash).unwrap();
		let chunk = snappy::decompress(&compressed).unwrap();
		rebuilder.feed(&chunk, engine.as_ref(), &flag).unwrap();
	}

	rebuilder.finalize(engine.as_ref()).unwrap();
	drop(rebuilder);

	// and test it.
	let new_chain = BlockChain::new(Default::default(), &genesis, new_db);
	assert_eq!(new_chain.best_block_hash(), best_hash);
}

#[test]
fn chunk_and_restore_500() { chunk_and_restore(500) }

#[test]
fn chunk_and_restore_40k() { chunk_and_restore(40000) }

#[test]
fn checks_flag() {
	use rlp::RlpStream;
	use util::H256;

	let mut stream = RlpStream::new_list(5);

	stream.append(&100u64)
		.append(&H256::default())
		.append(&(!0u64));

	stream.append_empty_data().append_empty_data();

	let genesis = {
		let mut canon_chain = ChainGenerator::default();
		let mut finalizer = BlockFinalizer::default();
		canon_chain.generate(&mut finalizer).unwrap()
	};

	let chunk = stream.out();

	let db = Arc::new(kvdb::in_memory(::db::NUM_COLUMNS.unwrap_or(0)));
	let engine = Arc::new(::engines::NullEngine::default());
	let chain = BlockChain::new(Default::default(), &genesis, db.clone());

	let manifest = ::snapshot::ManifestData {
		version: 2,
		state_hashes: Vec::new(),
		block_hashes: Vec::new(),
		state_root: ::hash::KECCAK_NULL_RLP,
		block_number: 102,
		block_hash: H256::default(),
	};

	let mut rebuilder = SNAPSHOT_MODE.rebuilder(chain, db.clone(), &manifest).unwrap();

	match rebuilder.feed(&chunk, engine.as_ref(), &AtomicBool::new(false)) {
		Err(Error::Snapshot(SnapshotError::RestorationAborted)) => {}
		_ => panic!("Wrong result on abort flag set")
	}
}