// Copyright 2018 The Grin Developers
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

pub mod common;

use self::core::core::hash::Hashed;
use self::core::core::verifier_cache::LruVerifierCache;
use self::core::core::{Block, BlockHeader, Transaction};
use self::core::libtx;
use self::core::pow::Difficulty;
use self::keychain::{ExtKeychain, Keychain};
use self::util::RwLock;
use crate::common::*;
use grin_core as core;
use grin_keychain as keychain;
use grin_util as util;
use std::sync::Arc;

#[test]
fn test_transaction_pool_block_building() {
	util::init_test_logger();
	let keychain: ExtKeychain = Keychain::from_random_seed().unwrap();

	let db_root = ".grin_block_building".to_string();
	clean_output_dir(db_root.clone());
	let mut chain = ChainAdapter::init(db_root.clone()).unwrap();

	let verifier_cache = Arc::new(RwLock::new(LruVerifierCache::new()));

	// Initialize the chain/txhashset with an initial block
	// so we have a non-empty UTXO set.
	let add_block = |prev_header: BlockHeader, txs: Vec<Transaction>, chain: &mut ChainAdapter| {
		let height = prev_header.height + 1;
		let key_id = ExtKeychain::derive_key_id(1, height as u32, 0, 0, 0);
		let fee = txs.iter().map(|x| x.fee()).sum();
		let reward = libtx::reward::output(&keychain, &key_id, fee).unwrap();
		let mut block = Block::new(&prev_header, txs, Difficulty::min(), reward).unwrap();

		// Set the prev_root to the prev hash for testing purposes (no MMR to obtain a root from).
		block.header.prev_root = prev_header.hash();

		chain.update_db_for_block(&block);
		block
	};

	let block = add_block(BlockHeader::default(), vec![], &mut chain);
	let header = block.header;

	// Now create tx to spend that first coinbase (now matured).
	// Provides us with some useful outputs to test with.
	let initial_tx = test_transaction_spending_coinbase(&keychain, &header, vec![10, 20, 30, 40]);

	// Mine that initial tx so we can spend it with multiple txs
	let block = add_block(header, vec![initial_tx], &mut chain);
	let header = block.header;

	// Initialize a new pool with our chain adapter.
	let pool = RwLock::new(test_setup(Arc::new(chain.clone()), verifier_cache));

	let root_tx_1 = test_transaction(&keychain, vec![10, 20], vec![24]);
	let root_tx_2 = test_transaction(&keychain, vec![30], vec![28]);
	let root_tx_3 = test_transaction(&keychain, vec![40], vec![38]);

	let child_tx_1 = test_transaction(&keychain, vec![24], vec![22]);
	let child_tx_2 = test_transaction(&keychain, vec![38], vec![32]);

	{
		let mut write_pool = pool.write();

		// Add the three root txs to the pool.
		write_pool
			.add_to_pool(test_source(), root_tx_1, false, &header)
			.unwrap();
		write_pool
			.add_to_pool(test_source(), root_tx_2, false, &header)
			.unwrap();
		write_pool
			.add_to_pool(test_source(), root_tx_3, false, &header)
			.unwrap();

		// Now add the two child txs to the pool.
		write_pool
			.add_to_pool(test_source(), child_tx_1.clone(), false, &header)
			.unwrap();
		write_pool
			.add_to_pool(test_source(), child_tx_2.clone(), false, &header)
			.unwrap();

		assert_eq!(write_pool.total_size(), 5);
	}

	let txs = {
		let read_pool = pool.read();
		read_pool.prepare_mineable_transactions().unwrap()
	};
	// children should have been aggregated into parents
	assert_eq!(txs.len(), 3);

	let block = add_block(header, txs, &mut chain);

	// Now reconcile the transaction pool with the new block
	// and check the resulting contents of the pool are what we expect.
	{
		let mut write_pool = pool.write();
		write_pool.reconcile_block(&block).unwrap();

		assert_eq!(write_pool.total_size(), 0);
	}
}
