// 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/>.

//! Test client.

use util::*;
use transaction::{Transaction, LocalizedTransaction, Action};
use blockchain::TreeRoute;
use client::{BlockChainClient, BlockChainInfo, BlockStatus, BlockId, TransactionId};
use header::{Header as BlockHeader, BlockNumber};
use filter::Filter;
use log_entry::LocalizedLogEntry;
use receipt::Receipt;
use error::{ImportResult, Error};
use block_queue::BlockQueueInfo;
use block::ClosedBlock;

/// Test client.
pub struct TestBlockChainClient {
	/// Blocks.
	pub blocks: RwLock<HashMap<H256, Bytes>>,
	/// Mapping of numbers to hashes.
 	pub numbers: RwLock<HashMap<usize, H256>>,
	/// Genesis block hash.
	pub genesis_hash: H256,
	/// Last block hash.
	pub last_hash: RwLock<H256>,
	/// Difficulty.
	pub difficulty: RwLock<U256>,
}

#[derive(Clone)]
/// Used for generating test client blocks.
pub enum EachBlockWith {
	/// Plain block.
	Nothing,
	/// Block with an uncle.
	Uncle,
	/// Block with a transaction.
	Transaction,
	/// Block with an uncle and transaction.
	UncleAndTransaction
}

impl TestBlockChainClient {
	/// Creates new test client.
	pub fn new() -> TestBlockChainClient {

		let mut client = TestBlockChainClient {
			blocks: RwLock::new(HashMap::new()),
			numbers: RwLock::new(HashMap::new()),
			genesis_hash: H256::new(),
			last_hash: RwLock::new(H256::new()),
			difficulty: RwLock::new(From::from(0)),
		};
		client.add_blocks(1, EachBlockWith::Nothing); // add genesis block
		client.genesis_hash = client.last_hash.read().unwrap().clone();
		client
	}

	/// Add blocks to test client.
	pub fn add_blocks(&mut self, count: usize, with: EachBlockWith) {
		let len = self.numbers.read().unwrap().len();
		for n in len..(len + count) {
			let mut header = BlockHeader::new();
			header.difficulty = From::from(n);
			header.parent_hash = self.last_hash.read().unwrap().clone();
			header.number = n as BlockNumber;
			let uncles = match with {
				EachBlockWith::Uncle | EachBlockWith::UncleAndTransaction => {
					let mut uncles = RlpStream::new_list(1);
					let mut uncle_header = BlockHeader::new();
					uncle_header.difficulty = From::from(n);
					uncle_header.parent_hash = self.last_hash.read().unwrap().clone();
					uncle_header.number = n as BlockNumber;
					uncles.append(&uncle_header);
					header.uncles_hash = uncles.as_raw().sha3();
					uncles
				},
				_ => RlpStream::new_list(0)
			};
			let txs = match with {
				EachBlockWith::Transaction | EachBlockWith::UncleAndTransaction => {
					let mut txs = RlpStream::new_list(1);
					let keypair = KeyPair::create().unwrap();
					let tx = Transaction {
						action: Action::Create,
						value: U256::from(100),
						data: "3331600055".from_hex().unwrap(),
						gas: U256::from(100_000),
						gas_price: U256::one(),
						nonce: U256::zero()
					};
					let signed_tx = tx.sign(&keypair.secret());
					txs.append(&signed_tx);
					txs.out()
				},
				_ => rlp::NULL_RLP.to_vec()
			};

			let mut rlp = RlpStream::new_list(3);
			rlp.append(&header);
			rlp.append_raw(&txs, 1);
			rlp.append_raw(uncles.as_raw(), 1);
			self.import_block(rlp.as_raw().to_vec()).unwrap();
		}
	}

	/// TODO:
	pub fn corrupt_block(&mut self, n: BlockNumber) {
		let hash = self.block_hash(BlockId::Number(n)).unwrap();
		let mut header: BlockHeader = decode(&self.block_header(BlockId::Number(n)).unwrap());
		header.parent_hash = H256::new();
		let mut rlp = RlpStream::new_list(3);
		rlp.append(&header);
		rlp.append_raw(&rlp::NULL_RLP, 1);
		rlp.append_raw(&rlp::NULL_RLP, 1);
		self.blocks.write().unwrap().insert(hash, rlp.out());
	}

	/// TODO:
	pub fn block_hash_delta_minus(&mut self, delta: usize) -> H256 {
		let blocks_read = self.numbers.read().unwrap();
		let index = blocks_read.len() - delta;
		blocks_read[&index].clone()
	}

	fn block_hash(&self, id: BlockId) -> Option<H256> {
		match id {
			BlockId::Hash(hash) => Some(hash),
			BlockId::Number(n) => self.numbers.read().unwrap().get(&(n as usize)).cloned(),
			BlockId::Earliest => self.numbers.read().unwrap().get(&0).cloned(),
			BlockId::Latest => self.numbers.read().unwrap().get(&(self.numbers.read().unwrap().len() - 1)).cloned()
		}
	}
}

impl BlockChainClient for TestBlockChainClient {
	fn block_total_difficulty(&self, _id: BlockId) -> Option<U256> {
		Some(U256::zero())
	}

	fn block_hash(&self, _id: BlockId) -> Option<H256> {
		unimplemented!();
	}

	fn nonce(&self, _address: &Address) -> U256 {
		U256::zero()
	}

	fn code(&self, _address: &Address) -> Option<Bytes> {
		unimplemented!();
	}

	fn transaction(&self, _id: TransactionId) -> Option<LocalizedTransaction> {
		unimplemented!();
	}

	fn blocks_with_bloom(&self, _bloom: &H2048, _from_block: BlockId, _to_block: BlockId) -> Option<Vec<BlockNumber>> {
		unimplemented!();
	}

	fn logs(&self, _filter: Filter) -> Vec<LocalizedLogEntry> {
		unimplemented!();
	}

	fn sealing_block(&self) -> &Mutex<Option<ClosedBlock>> {
		unimplemented!();
	}

	fn submit_seal(&self, _pow_hash: H256, _seal: Vec<Bytes>) -> Result<(), Error> {
		unimplemented!();
	}

	fn block_header(&self, id: BlockId) -> Option<Bytes> {
		self.block_hash(id).and_then(|hash| self.blocks.read().unwrap().get(&hash).map(|r| Rlp::new(r).at(0).as_raw().to_vec()))
	}

	fn block_body(&self, id: BlockId) -> Option<Bytes> {
		self.block_hash(id).and_then(|hash| self.blocks.read().unwrap().get(&hash).map(|r| {
			let mut stream = RlpStream::new_list(2);
			stream.append_raw(Rlp::new(&r).at(1).as_raw(), 1);
			stream.append_raw(Rlp::new(&r).at(2).as_raw(), 1);
			stream.out()
		}))
	}

	fn block(&self, id: BlockId) -> Option<Bytes> {
		self.block_hash(id).and_then(|hash| self.blocks.read().unwrap().get(&hash).cloned())
	}

	fn block_status(&self, id: BlockId) -> BlockStatus {
		match id {
			BlockId::Number(number) if (number as usize) < self.blocks.read().unwrap().len() => BlockStatus::InChain,
			BlockId::Hash(ref hash) if self.blocks.read().unwrap().get(hash).is_some() => BlockStatus::InChain,
			_ => BlockStatus::Unknown
		}
	}

	// works only if blocks are one after another 1 -> 2 -> 3
	fn tree_route(&self, from: &H256, to: &H256) -> Option<TreeRoute> {
		Some(TreeRoute {
			ancestor: H256::new(),
			index: 0,
			blocks: {
				let numbers_read = self.numbers.read().unwrap();
				let mut adding = false;

				let mut blocks = Vec::new();
				for (_, hash) in numbers_read.iter().sort_by(|tuple1, tuple2| tuple1.0.cmp(tuple2.0)) {
					if hash == to {
						if adding {
							blocks.push(hash.clone());
						}
						adding = false;
						break;
					}
					if hash == from {
						adding = true;
					}
					if adding {
						blocks.push(hash.clone());
					}
				}
				if adding { Vec::new() } else { blocks }
			}
		})
	}

	// TODO: returns just hashes instead of node state rlp(?)
	fn state_data(&self, hash: &H256) -> Option<Bytes> {
		// starts with 'f' ?
		if *hash > H256::from("f000000000000000000000000000000000000000000000000000000000000000") {
			let mut rlp = RlpStream::new();
			rlp.append(&hash.clone());
			return Some(rlp.out());
		}
		None
	}

	fn block_receipts(&self, hash: &H256) -> Option<Bytes> {
		// starts with 'f' ?
		if *hash > H256::from("f000000000000000000000000000000000000000000000000000000000000000") {
			let receipt = Receipt::new(
				H256::zero(),
				U256::zero(),
				vec![]);
			let mut rlp = RlpStream::new();
			rlp.append(&receipt);
			return Some(rlp.out());
		}
		None
	}

	fn import_block(&self, b: Bytes) -> ImportResult {
		let header = Rlp::new(&b).val_at::<BlockHeader>(0);
		let h = header.hash();
		let number: usize = header.number as usize;
		if number > self.blocks.read().unwrap().len() {
			panic!("Unexpected block number. Expected {}, got {}", self.blocks.read().unwrap().len(), number);
		}
		if number > 0 {
			match self.blocks.read().unwrap().get(&header.parent_hash) {
				Some(parent) => {
					let parent = Rlp::new(parent).val_at::<BlockHeader>(0);
					if parent.number != (header.number - 1) {
						panic!("Unexpected block parent");
					}
				},
				None => {
					panic!("Unknown block parent {:?} for block {}", header.parent_hash, number);
				}
			}
		}
		let len = self.numbers.read().unwrap().len();
		if number == len {
			{
				let mut difficulty = self.difficulty.write().unwrap();
				*difficulty.deref_mut() = *difficulty.deref() + header.difficulty;
			}
			mem::replace(self.last_hash.write().unwrap().deref_mut(), h.clone());
			self.blocks.write().unwrap().insert(h.clone(), b);
			self.numbers.write().unwrap().insert(number, h.clone());
			let mut parent_hash = header.parent_hash;
			if number > 0 {
				let mut n = number - 1;
				while n > 0 && self.numbers.read().unwrap()[&n] != parent_hash {
					*self.numbers.write().unwrap().get_mut(&n).unwrap() = parent_hash.clone();
					n -= 1;
					parent_hash = Rlp::new(&self.blocks.read().unwrap()[&parent_hash]).val_at::<BlockHeader>(0).parent_hash;
				}
			}
		}
		else {
			self.blocks.write().unwrap().insert(h.clone(), b.to_vec());
		}
		Ok(h)
	}

	fn queue_info(&self) -> BlockQueueInfo {
		BlockQueueInfo {
			verified_queue_size: 0,
			unverified_queue_size: 0,
			verifying_queue_size: 0,
			max_queue_size: 0,
			max_mem_use: 0,
			mem_used: 0,
		}
	}

	fn clear_queue(&self) {
	}

	fn chain_info(&self) -> BlockChainInfo {
		BlockChainInfo {
			total_difficulty: *self.difficulty.read().unwrap(),
			pending_total_difficulty: *self.difficulty.read().unwrap(),
			genesis_hash: self.genesis_hash.clone(),
			best_block_hash: self.last_hash.read().unwrap().clone(),
			best_block_number: self.blocks.read().unwrap().len() as BlockNumber - 1,
		}
	}
}