// Copyright 2015-2020 Parity Technologies (UK) Ltd.
// This file is part of OpenEthereum.

// OpenEthereum 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.

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

//! Block and transaction verification functions
//!
//! Block verification is done in 3 steps
//! 1. Quick verification upon adding to the block queue
//! 2. Signatures verification done in the queue.
//! 3. Final verification against the blockchain done before enactment.

use std::{
    collections::HashSet,
    time::{Duration, SystemTime, UNIX_EPOCH},
};

use bytes::Bytes;
use hash::keccak;
use heapsize::HeapSizeOf;
use rlp::Rlp;
use triehash::ordered_trie_root;
use unexpected::{Mismatch, OutOfBounds};

use blockchain::*;
use call_contract::CallContract;
use client::BlockInfo;
use engines::{EthEngine, MAX_UNCLE_AGE};
use error::{BlockError, Error};
use types::{header::Header, transaction::SignedTransaction, BlockNumber};
use verification::queue::kind::blocks::Unverified;

use time_utils::CheckedSystemTime;

/// Preprocessed block data gathered in `verify_block_unordered` call
pub struct PreverifiedBlock {
    /// Populated block header
    pub header: Header,
    /// Populated block transactions
    pub transactions: Vec<SignedTransaction>,
    /// Populated block uncles
    pub uncles: Vec<Header>,
    /// Block bytes
    pub bytes: Bytes,
}

impl HeapSizeOf for PreverifiedBlock {
    fn heap_size_of_children(&self) -> usize {
        self.header.heap_size_of_children()
            + self.transactions.heap_size_of_children()
            + self.bytes.heap_size_of_children()
    }
}

// t_nb 4.0 Phase 1 quick block verification. Only does checks that are cheap. Operates on a single block
pub fn verify_block_basic(
    block: &Unverified,
    engine: &dyn EthEngine,
    check_seal: bool,
) -> Result<(), Error> {
    // t_nb 4.1  verify header params
    verify_header_params(&block.header, engine, true, check_seal)?;
    // t_nb 4.2 verify header time (addded in new OE version)
    // t_nb 4.3 verify block integrity
    verify_block_integrity(block)?;

    if check_seal {
        // t_nb 4.4 Check block seal. It calls engine to verify block basic
        engine.verify_block_basic(&block.header)?;
    }

    // t_nb 4.5 for all uncled verify header and call engine to verify block basic
    for uncle in &block.uncles {
        // t_nb 4.5.1
        verify_header_params(uncle, engine, false, check_seal)?;
        if check_seal {
            // t_nb 4.5.2
            engine.verify_block_basic(uncle)?;
        }
    }

    // t_nb 4.6 call engine.gas_limit_override (Used only by Aura) TODO added in new version

    // t_nb 4.7 for every transaction call engine.verify_transaction_basic
    for t in &block.transactions {
        engine.verify_transaction_basic(t, &block.header)?;
    }

    Ok(())
}

// t_nb 5.0 Phase 2 verification. Perform costly checks such as transaction signatures and block nonce for ethash.
/// Still operates on a individual block
/// Returns a `PreverifiedBlock` structure populated with transactions
pub fn verify_block_unordered(
    block: Unverified,
    engine: &dyn EthEngine,
    check_seal: bool,
) -> Result<PreverifiedBlock, Error> {
    let header = block.header;
    if check_seal {
        // t_nb 5.1
        engine.verify_block_unordered(&header)?;
        for uncle in &block.uncles {
            // t_nb 5.2
            engine.verify_block_unordered(uncle)?;
        }
    }
    // Verify transactions.
    let nonce_cap = if header.number() >= engine.params().dust_protection_transition {
        Some((engine.params().nonce_cap_increment * header.number()).into())
    } else {
        None
    };

    // t_nb 5.3 iterate over all transactions
    let transactions = block
        .transactions
        .into_iter()
        .map(|t| {
            // t_nb 5.3.1 call verify_unordered. Check signatures and calculate address
            let t = engine.verify_transaction_unordered(t, &header)?;
            // t_nb 5.3.2 check if nonce is more then max nonce (EIP-168 and EIP169)
            if let Some(max_nonce) = nonce_cap {
                if t.nonce >= max_nonce {
                    return Err(BlockError::TooManyTransactions(t.sender()).into());
                }
            }
            Ok(t)
        })
        .collect::<Result<Vec<_>, Error>>()?;

    Ok(PreverifiedBlock {
        header,
        transactions,
        uncles: block.uncles,
        bytes: block.bytes,
    })
}

/// Parameters for full verification of block family
pub struct FullFamilyParams<'a, C: BlockInfo + CallContract + 'a> {
    /// Preverified block
    pub block: &'a PreverifiedBlock,

    /// Block provider to use during verification
    pub block_provider: &'a dyn BlockProvider,

    /// Engine client to use during verification
    pub client: &'a C,
}

// t_nb 6.3 Phase 3 verification. Check block information against parent and uncles.
pub fn verify_block_family<C: BlockInfo + CallContract>(
    header: &Header,
    parent: &Header,
    engine: &dyn EthEngine,
    do_full: Option<FullFamilyParams<C>>,
) -> Result<(), Error> {
    // TODO: verify timestamp
    // t_nb 6.3.1 verify parent
    verify_parent(&header, &parent, engine)?;
    engine.verify_block_family(&header, &parent)?;

    let params = match do_full {
        Some(x) => x,
        None => return Ok(()),
    };

    // t_nb 6.3.2 verify uncles
    verify_uncles(params.block, params.block_provider, engine)?;

    // t_nb 6.3.3 verify all transactions
    for tx in &params.block.transactions {
        // transactions are verified against the parent header since the current
        // state wasn't available when the tx was created
        engine
            .machine()
            .verify_transaction(tx, parent, params.client)?;
    }

    Ok(())
}

fn verify_uncles(
    block: &PreverifiedBlock,
    bc: &dyn BlockProvider,
    engine: &dyn EthEngine,
) -> Result<(), Error> {
    let header = &block.header;
    let num_uncles = block.uncles.len();
    let max_uncles = engine.maximum_uncle_count(header.number());
    if num_uncles != 0 {
        if num_uncles > max_uncles {
            return Err(From::from(BlockError::TooManyUncles(OutOfBounds {
                min: None,
                max: Some(max_uncles),
                found: num_uncles,
            })));
        }

        let mut excluded = HashSet::new();
        excluded.insert(header.hash());
        let mut hash = header.parent_hash().clone();
        excluded.insert(hash.clone());
        for _ in 0..MAX_UNCLE_AGE {
            match bc.block_details(&hash) {
                Some(details) => {
                    excluded.insert(details.parent);
                    let b = bc
                        .block(&hash)
                        .expect("parent already known to be stored; qed");
                    excluded.extend(b.uncle_hashes());
                    hash = details.parent;
                }
                None => break,
            }
        }

        let mut verified = HashSet::new();
        for uncle in &block.uncles {
            if excluded.contains(&uncle.hash()) {
                return Err(From::from(BlockError::UncleInChain(uncle.hash())));
            }

            if verified.contains(&uncle.hash()) {
                return Err(From::from(BlockError::DuplicateUncle(uncle.hash())));
            }

            // m_currentBlock.number() - uncle.number()		m_cB.n - uP.n()
            // 1											2
            // 2
            // 3
            // 4
            // 5
            // 6											7
            //												(8 Invalid)

            let depth = if header.number() > uncle.number() {
                header.number() - uncle.number()
            } else {
                0
            };
            if depth > MAX_UNCLE_AGE as u64 {
                return Err(From::from(BlockError::UncleTooOld(OutOfBounds {
                    min: Some(header.number() - depth),
                    max: Some(header.number() - 1),
                    found: uncle.number(),
                })));
            } else if depth < 1 {
                return Err(From::from(BlockError::UncleIsBrother(OutOfBounds {
                    min: Some(header.number() - depth),
                    max: Some(header.number() - 1),
                    found: uncle.number(),
                })));
            }

            // cB
            // cB.p^1	    1 depth, valid uncle
            // cB.p^2	---/  2
            // cB.p^3	-----/  3
            // cB.p^4	-------/  4
            // cB.p^5	---------/  5
            // cB.p^6	-----------/  6
            // cB.p^7	-------------/
            // cB.p^8
            let mut expected_uncle_parent = header.parent_hash().clone();
            let uncle_parent = bc.block_header_data(&uncle.parent_hash()).ok_or_else(|| {
                Error::from(BlockError::UnknownUncleParent(uncle.parent_hash().clone()))
            })?;
            for _ in 0..depth {
                match bc.block_details(&expected_uncle_parent) {
                    Some(details) => {
                        expected_uncle_parent = details.parent;
                    }
                    None => break,
                }
            }
            if expected_uncle_parent != uncle_parent.hash() {
                return Err(From::from(BlockError::UncleParentNotInChain(
                    uncle_parent.hash(),
                )));
            }

            let uncle_parent = uncle_parent.decode()?;
            verify_parent(&uncle, &uncle_parent, engine)?;
            engine.verify_block_family(&uncle, &uncle_parent)?;
            verified.insert(uncle.hash());
        }
    }

    Ok(())
}

/// Phase 4 verification. Check block information against transaction enactment results,
pub fn verify_block_final(expected: &Header, got: &Header) -> Result<(), Error> {
    if expected.state_root() != got.state_root() {
        return Err(From::from(BlockError::InvalidStateRoot(Mismatch {
            expected: *expected.state_root(),
            found: *got.state_root(),
        })));
    }
    if expected.gas_used() != got.gas_used() {
        return Err(From::from(BlockError::InvalidGasUsed(Mismatch {
            expected: *expected.gas_used(),
            found: *got.gas_used(),
        })));
    }
    if expected.log_bloom() != got.log_bloom() {
        return Err(From::from(BlockError::InvalidLogBloom(Box::new(
            Mismatch {
                expected: *expected.log_bloom(),
                found: *got.log_bloom(),
            },
        ))));
    }
    if expected.receipts_root() != got.receipts_root() {
        return Err(From::from(BlockError::InvalidReceiptsRoot(Mismatch {
            expected: *expected.receipts_root(),
            found: *got.receipts_root(),
        })));
    }
    Ok(())
}

/// Check basic header parameters.
pub fn verify_header_params(
    header: &Header,
    engine: &dyn EthEngine,
    is_full: bool,
    check_seal: bool,
) -> Result<(), Error> {
    if check_seal {
        let expected_seal_fields = engine.seal_fields(header);
        if header.seal().len() != expected_seal_fields {
            return Err(From::from(BlockError::InvalidSealArity(Mismatch {
                expected: expected_seal_fields,
                found: header.seal().len(),
            })));
        }
    }

    if header.number() >= From::from(BlockNumber::max_value()) {
        return Err(From::from(BlockError::RidiculousNumber(OutOfBounds {
            max: Some(From::from(BlockNumber::max_value())),
            min: None,
            found: header.number(),
        })));
    }
    if header.gas_used() > header.gas_limit() {
        return Err(From::from(BlockError::TooMuchGasUsed(OutOfBounds {
            max: Some(*header.gas_limit()),
            min: None,
            found: *header.gas_used(),
        })));
    }
    let min_gas_limit = engine.params().min_gas_limit;
    if header.gas_limit() < &min_gas_limit {
        return Err(From::from(BlockError::InvalidGasLimit(OutOfBounds {
            min: Some(min_gas_limit),
            max: None,
            found: *header.gas_limit(),
        })));
    }
    if let Some(limit) = engine.maximum_gas_limit() {
        if header.gas_limit() > &limit {
            return Err(From::from(::error::BlockError::InvalidGasLimit(
                OutOfBounds {
                    min: None,
                    max: Some(limit),
                    found: *header.gas_limit(),
                },
            )));
        }
    }
    let maximum_extra_data_size = engine.maximum_extra_data_size();
    if header.number() != 0 && header.extra_data().len() > maximum_extra_data_size {
        return Err(From::from(BlockError::ExtraDataOutOfBounds(OutOfBounds {
            min: None,
            max: Some(maximum_extra_data_size),
            found: header.extra_data().len(),
        })));
    }

    if let Some(ref ext) = engine.machine().ethash_extensions() {
        if header.number() >= ext.dao_hardfork_transition
            && header.number() <= ext.dao_hardfork_transition + 9
            && header.extra_data()[..] != b"dao-hard-fork"[..]
        {
            return Err(From::from(BlockError::ExtraDataOutOfBounds(OutOfBounds {
                min: None,
                max: None,
                found: 0,
            })));
        }
    }

    if is_full {
        const ACCEPTABLE_DRIFT: Duration = Duration::from_secs(15);
        // this will resist overflow until `year 2037`
        let max_time = SystemTime::now() + ACCEPTABLE_DRIFT;
        let invalid_threshold = max_time + ACCEPTABLE_DRIFT * 9;
        let timestamp =
            CheckedSystemTime::checked_add(UNIX_EPOCH, Duration::from_secs(header.timestamp()))
                .ok_or(BlockError::TimestampOverflow)?;

        if timestamp > invalid_threshold {
            return Err(From::from(BlockError::InvalidTimestamp(OutOfBounds {
                max: Some(max_time),
                min: None,
                found: timestamp,
            })));
        }

        if timestamp > max_time {
            return Err(From::from(BlockError::TemporarilyInvalid(OutOfBounds {
                max: Some(max_time),
                min: None,
                found: timestamp,
            })));
        }
    }

    Ok(())
}

/// Check header parameters agains parent header.
fn verify_parent(header: &Header, parent: &Header, engine: &dyn EthEngine) -> Result<(), Error> {
    assert!(
        header.parent_hash().is_zero() || &parent.hash() == header.parent_hash(),
        "Parent hash should already have been verified; qed"
    );

    let gas_limit_divisor = engine.params().gas_limit_bound_divisor;

    if !engine.is_timestamp_valid(header.timestamp(), parent.timestamp()) {
        let now = SystemTime::now();
        let min = CheckedSystemTime::checked_add(
            now,
            Duration::from_secs(parent.timestamp().saturating_add(1)),
        )
        .ok_or(BlockError::TimestampOverflow)?;
        let found = CheckedSystemTime::checked_add(now, Duration::from_secs(header.timestamp()))
            .ok_or(BlockError::TimestampOverflow)?;
        return Err(From::from(BlockError::InvalidTimestamp(OutOfBounds {
            max: None,
            min: Some(min),
            found,
        })));
    }
    if header.number() != parent.number() + 1 {
        return Err(From::from(BlockError::InvalidNumber(Mismatch {
            expected: parent.number() + 1,
            found: header.number(),
        })));
    }

    if header.number() == 0 {
        return Err(BlockError::RidiculousNumber(OutOfBounds {
            min: Some(1),
            max: None,
            found: header.number(),
        })
        .into());
    }

    let parent_gas_limit = *parent.gas_limit();
    let min_gas = parent_gas_limit - parent_gas_limit / gas_limit_divisor;
    let max_gas = parent_gas_limit + parent_gas_limit / gas_limit_divisor;
    if header.gas_limit() <= &min_gas || header.gas_limit() >= &max_gas {
        return Err(From::from(BlockError::InvalidGasLimit(OutOfBounds {
            min: Some(min_gas),
            max: Some(max_gas),
            found: *header.gas_limit(),
        })));
    }

    Ok(())
}

/// Verify block data against header: transactions root and uncles hash.
fn verify_block_integrity(block: &Unverified) -> Result<(), Error> {
    let block_rlp = Rlp::new(&block.bytes);
    let tx = block_rlp.at(1)?;
    let expected_root = ordered_trie_root(tx.iter().map(|r| r.as_raw()));
    if &expected_root != block.header.transactions_root() {
        bail!(BlockError::InvalidTransactionsRoot(Mismatch {
            expected: expected_root,
            found: *block.header.transactions_root(),
        }));
    }
    let expected_uncles = keccak(block_rlp.at(2)?.as_raw());
    if &expected_uncles != block.header.uncles_hash() {
        bail!(BlockError::InvalidUnclesHash(Mismatch {
            expected: expected_uncles,
            found: *block.header.uncles_hash(),
        }));
    }
    Ok(())
}

#[cfg(test)]
mod tests {
    use super::*;

    use blockchain::{BlockDetails, BlockReceipts, TransactionAddress};
    use engines::EthEngine;
    use error::{BlockError::*, ErrorKind};
    use ethereum_types::{BloomRef, H256, U256};
    use ethkey::{Generator, Random};
    use hash::keccak;
    use rlp;
    use spec::{CommonParams, Spec};
    use std::{
        collections::{BTreeMap, HashMap},
        time::{SystemTime, UNIX_EPOCH},
    };
    use test_helpers::{create_test_block, create_test_block_with_data};
    use triehash::ordered_trie_root;
    use types::{
        encoded,
        log_entry::{LocalizedLogEntry, LogEntry},
        transaction::{Action, SignedTransaction, Transaction, UnverifiedTransaction},
    };

    fn check_ok(result: Result<(), Error>) {
        result.unwrap_or_else(|e| panic!("Block verification failed: {:?}", e));
    }

    fn check_fail(result: Result<(), Error>, e: BlockError) {
        match result {
            Err(Error(ErrorKind::Block(ref error), _)) if *error == e => (),
            Err(other) => panic!(
                "Block verification failed.\nExpected: {:?}\nGot: {:?}",
                e, other
            ),
            Ok(_) => panic!("Block verification failed.\nExpected: {:?}\nGot: Ok", e),
        }
    }

    fn check_fail_timestamp(result: Result<(), Error>, temp: bool) {
        let name = if temp {
            "TemporarilyInvalid"
        } else {
            "InvalidTimestamp"
        };
        match result {
            Err(Error(ErrorKind::Block(BlockError::InvalidTimestamp(_)), _)) if !temp => (),
            Err(Error(ErrorKind::Block(BlockError::TemporarilyInvalid(_)), _)) if temp => (),
            Err(other) => panic!(
                "Block verification failed.\nExpected: {}\nGot: {:?}",
                name, other
            ),
            Ok(_) => panic!("Block verification failed.\nExpected: {}\nGot: Ok", name),
        }
    }

    struct TestBlockChain {
        blocks: HashMap<H256, Bytes>,
        numbers: HashMap<BlockNumber, H256>,
    }

    impl Default for TestBlockChain {
        fn default() -> Self {
            TestBlockChain::new()
        }
    }

    impl TestBlockChain {
        pub fn new() -> Self {
            TestBlockChain {
                blocks: HashMap::new(),
                numbers: HashMap::new(),
            }
        }

        pub fn insert(&mut self, bytes: Bytes) {
            let header = Unverified::from_rlp(bytes.clone()).unwrap().header;
            let hash = header.hash();
            self.blocks.insert(hash, bytes);
            self.numbers.insert(header.number(), hash);
        }
    }

    impl BlockProvider for TestBlockChain {
        fn is_known(&self, hash: &H256) -> bool {
            self.blocks.contains_key(hash)
        }

        fn first_block(&self) -> Option<H256> {
            unimplemented!()
        }

        /// Get raw block data
        fn block(&self, hash: &H256) -> Option<encoded::Block> {
            self.blocks.get(hash).cloned().map(encoded::Block::new)
        }

        fn block_header_data(&self, hash: &H256) -> Option<encoded::Header> {
            self.block(hash)
                .map(|b| b.header_view().rlp().as_raw().to_vec())
                .map(encoded::Header::new)
        }

        fn block_body(&self, hash: &H256) -> Option<encoded::Body> {
            self.block(hash)
                .map(|b| BlockChain::block_to_body(&b.into_inner()))
                .map(encoded::Body::new)
        }

        fn best_ancient_block(&self) -> Option<H256> {
            None
        }

        /// Get the familial details concerning a block.
        fn block_details(&self, hash: &H256) -> Option<BlockDetails> {
            self.blocks.get(hash).map(|bytes| {
                let header = Unverified::from_rlp(bytes.to_vec()).unwrap().header;
                BlockDetails {
                    number: header.number(),
                    total_difficulty: *header.difficulty(),
                    parent: *header.parent_hash(),
                    children: Vec::new(),
                    is_finalized: false,
                }
            })
        }

        fn transaction_address(&self, _hash: &H256) -> Option<TransactionAddress> {
            unimplemented!()
        }

        /// Get the hash of given block's number.
        fn block_hash(&self, index: BlockNumber) -> Option<H256> {
            self.numbers.get(&index).cloned()
        }

        fn block_receipts(&self, _hash: &H256) -> Option<BlockReceipts> {
            unimplemented!()
        }

        fn blocks_with_bloom<'a, B, I, II>(
            &self,
            _blooms: II,
            _from_block: BlockNumber,
            _to_block: BlockNumber,
        ) -> Vec<BlockNumber>
        where
            BloomRef<'a>: From<B>,
            II: IntoIterator<Item = B, IntoIter = I> + Copy,
            I: Iterator<Item = B>,
            Self: Sized,
        {
            unimplemented!()
        }

        fn logs<F>(
            &self,
            _blocks: Vec<H256>,
            _matches: F,
            _limit: Option<usize>,
        ) -> Vec<LocalizedLogEntry>
        where
            F: Fn(&LogEntry) -> bool,
            Self: Sized,
        {
            unimplemented!()
        }
    }

    fn basic_test(bytes: &[u8], engine: &dyn EthEngine) -> Result<(), Error> {
        let unverified = Unverified::from_rlp(bytes.to_vec())?;
        verify_block_basic(&unverified, engine, true)
    }

    fn family_test<BC>(bytes: &[u8], engine: &dyn EthEngine, bc: &BC) -> Result<(), Error>
    where
        BC: BlockProvider,
    {
        let block = Unverified::from_rlp(bytes.to_vec()).unwrap();
        let header = block.header;
        let transactions: Vec<_> = block
            .transactions
            .into_iter()
            .map(SignedTransaction::new)
            .collect::<Result<_, _>>()?;

        // TODO: client is really meant to be used for state query here by machine
        // additions that need access to state (tx filter in specific)
        // no existing tests need access to test, so having this not function
        // is fine.
        let client = ::client::TestBlockChainClient::default();
        let parent = bc
            .block_header_data(header.parent_hash())
            .ok_or(BlockError::UnknownParent(*header.parent_hash()))?
            .decode()?;

        let block = PreverifiedBlock {
            header,
            transactions,
            uncles: block.uncles,
            bytes: bytes.to_vec(),
        };

        let full_params = FullFamilyParams {
            block: &block,
            block_provider: bc as &dyn BlockProvider,
            client: &client,
        };
        verify_block_family(&block.header, &parent, engine, Some(full_params))
    }

    fn unordered_test(bytes: &[u8], engine: &dyn EthEngine) -> Result<(), Error> {
        let un = Unverified::from_rlp(bytes.to_vec())?;
        verify_block_unordered(un, engine, false)?;
        Ok(())
    }

    #[test]
    fn test_verify_block_basic_with_invalid_transactions() {
        let spec = Spec::new_test();
        let engine = &*spec.engine;

        let block = {
            let mut rlp = rlp::RlpStream::new_list(3);
            let mut header = Header::default();
            // that's an invalid transaction list rlp
            let invalid_transactions = vec![vec![0u8]];
            header.set_transactions_root(ordered_trie_root(&invalid_transactions));
            header.set_gas_limit(engine.params().min_gas_limit);
            rlp.append(&header);
            rlp.append_list::<Vec<u8>, _>(&invalid_transactions);
            rlp.append_raw(&rlp::EMPTY_LIST_RLP, 1);
            rlp.out()
        };

        assert!(basic_test(&block, engine).is_err());
    }

    #[test]
    fn test_verify_block() {
        use rlp::RlpStream;

        // Test against morden
        let mut good = Header::new();
        let spec = Spec::new_test();
        let engine = &*spec.engine;

        let min_gas_limit = engine.params().min_gas_limit;
        good.set_gas_limit(min_gas_limit);
        good.set_timestamp(40);
        good.set_number(10);

        let keypair = Random.generate().unwrap();

        let tr1 = Transaction {
            action: Action::Create,
            value: U256::from(0),
            data: Bytes::new(),
            gas: U256::from(30_000),
            gas_price: U256::from(40_000),
            nonce: U256::one(),
        }
        .sign(keypair.secret(), None);

        let tr2 = Transaction {
            action: Action::Create,
            value: U256::from(0),
            data: Bytes::new(),
            gas: U256::from(30_000),
            gas_price: U256::from(40_000),
            nonce: U256::from(2),
        }
        .sign(keypair.secret(), None);

        let tr3 = Transaction {
            action: Action::Call(0x0.into()),
            value: U256::from(0),
            data: Bytes::new(),
            gas: U256::from(30_000),
            gas_price: U256::from(0),
            nonce: U256::zero(),
        }
        .null_sign(0);

        let good_transactions = [tr1.clone(), tr2.clone()];
        let eip86_transactions = [tr3.clone()];

        let diff_inc = U256::from(0x40);

        let mut parent6 = good.clone();
        parent6.set_number(6);
        let mut parent7 = good.clone();
        parent7.set_number(7);
        parent7.set_parent_hash(parent6.hash());
        parent7.set_difficulty(parent6.difficulty().clone() + diff_inc);
        parent7.set_timestamp(parent6.timestamp() + 10);
        let mut parent8 = good.clone();
        parent8.set_number(8);
        parent8.set_parent_hash(parent7.hash());
        parent8.set_difficulty(parent7.difficulty().clone() + diff_inc);
        parent8.set_timestamp(parent7.timestamp() + 10);

        let mut good_uncle1 = good.clone();
        good_uncle1.set_number(9);
        good_uncle1.set_parent_hash(parent8.hash());
        good_uncle1.set_difficulty(parent8.difficulty().clone() + diff_inc);
        good_uncle1.set_timestamp(parent8.timestamp() + 10);
        let mut ex = good_uncle1.extra_data().to_vec();
        ex.push(1u8);
        good_uncle1.set_extra_data(ex);

        let mut good_uncle2 = good.clone();
        good_uncle2.set_number(8);
        good_uncle2.set_parent_hash(parent7.hash());
        good_uncle2.set_difficulty(parent7.difficulty().clone() + diff_inc);
        good_uncle2.set_timestamp(parent7.timestamp() + 10);
        let mut ex = good_uncle2.extra_data().to_vec();
        ex.push(2u8);
        good_uncle2.set_extra_data(ex);

        let good_uncles = vec![good_uncle1.clone(), good_uncle2.clone()];
        let mut uncles_rlp = RlpStream::new();
        uncles_rlp.append_list(&good_uncles);
        let good_uncles_hash = keccak(uncles_rlp.as_raw());
        let good_transactions_root = ordered_trie_root(
            good_transactions
                .iter()
                .map(|t| ::rlp::encode::<UnverifiedTransaction>(t)),
        );
        let eip86_transactions_root = ordered_trie_root(
            eip86_transactions
                .iter()
                .map(|t| ::rlp::encode::<UnverifiedTransaction>(t)),
        );

        let mut parent = good.clone();
        parent.set_number(9);
        parent.set_timestamp(parent8.timestamp() + 10);
        parent.set_parent_hash(parent8.hash());
        parent.set_difficulty(parent8.difficulty().clone() + diff_inc);

        good.set_parent_hash(parent.hash());
        good.set_difficulty(parent.difficulty().clone() + diff_inc);
        good.set_timestamp(parent.timestamp() + 10);

        let mut bc = TestBlockChain::new();
        bc.insert(create_test_block(&good));
        bc.insert(create_test_block(&parent));
        bc.insert(create_test_block(&parent6));
        bc.insert(create_test_block(&parent7));
        bc.insert(create_test_block(&parent8));

        check_ok(basic_test(&create_test_block(&good), engine));

        let mut bad_header = good.clone();
        bad_header.set_transactions_root(eip86_transactions_root.clone());
        bad_header.set_uncles_hash(good_uncles_hash.clone());
        match basic_test(&create_test_block_with_data(&bad_header, &eip86_transactions, &good_uncles), engine) {
			Err(Error(ErrorKind::Transaction(ref e), _)) if e == &::ethkey::Error::InvalidSignature.into() => (),
			e => panic!("Block verification failed.\nExpected: Transaction Error (Invalid Signature)\nGot: {:?}", e),
		}

        let mut header = good.clone();
        header.set_transactions_root(good_transactions_root.clone());
        header.set_uncles_hash(good_uncles_hash.clone());
        check_ok(basic_test(
            &create_test_block_with_data(&header, &good_transactions, &good_uncles),
            engine,
        ));

        header.set_gas_limit(min_gas_limit - 1);
        check_fail(
            basic_test(&create_test_block(&header), engine),
            InvalidGasLimit(OutOfBounds {
                min: Some(min_gas_limit),
                max: None,
                found: header.gas_limit().clone(),
            }),
        );

        header = good.clone();
        header.set_number(BlockNumber::max_value());
        check_fail(
            basic_test(&create_test_block(&header), engine),
            RidiculousNumber(OutOfBounds {
                max: Some(BlockNumber::max_value()),
                min: None,
                found: header.number(),
            }),
        );

        header = good.clone();
        let gas_used = header.gas_limit().clone() + 1;
        header.set_gas_used(gas_used);
        check_fail(
            basic_test(&create_test_block(&header), engine),
            TooMuchGasUsed(OutOfBounds {
                max: Some(header.gas_limit().clone()),
                min: None,
                found: header.gas_used().clone(),
            }),
        );

        header = good.clone();
        let mut ex = header.extra_data().to_vec();
        ex.resize(engine.maximum_extra_data_size() + 1, 0u8);
        header.set_extra_data(ex);
        check_fail(
            basic_test(&create_test_block(&header), engine),
            ExtraDataOutOfBounds(OutOfBounds {
                max: Some(engine.maximum_extra_data_size()),
                min: None,
                found: header.extra_data().len(),
            }),
        );

        header = good.clone();
        let mut ex = header.extra_data().to_vec();
        ex.resize(engine.maximum_extra_data_size() + 1, 0u8);
        header.set_extra_data(ex);
        check_fail(
            basic_test(&create_test_block(&header), engine),
            ExtraDataOutOfBounds(OutOfBounds {
                max: Some(engine.maximum_extra_data_size()),
                min: None,
                found: header.extra_data().len(),
            }),
        );

        header = good.clone();
        header.set_uncles_hash(good_uncles_hash.clone());
        check_fail(
            basic_test(
                &create_test_block_with_data(&header, &good_transactions, &good_uncles),
                engine,
            ),
            InvalidTransactionsRoot(Mismatch {
                expected: good_transactions_root.clone(),
                found: header.transactions_root().clone(),
            }),
        );

        header = good.clone();
        header.set_transactions_root(good_transactions_root.clone());
        check_fail(
            basic_test(
                &create_test_block_with_data(&header, &good_transactions, &good_uncles),
                engine,
            ),
            InvalidUnclesHash(Mismatch {
                expected: good_uncles_hash.clone(),
                found: header.uncles_hash().clone(),
            }),
        );

        check_ok(family_test(&create_test_block(&good), engine, &bc));
        check_ok(family_test(
            &create_test_block_with_data(&good, &good_transactions, &good_uncles),
            engine,
            &bc,
        ));

        header = good.clone();
        header.set_parent_hash(H256::random());
        check_fail(
            family_test(
                &create_test_block_with_data(&header, &good_transactions, &good_uncles),
                engine,
                &bc,
            ),
            UnknownParent(header.parent_hash().clone()),
        );

        header = good.clone();
        header.set_timestamp(10);
        check_fail_timestamp(
            family_test(
                &create_test_block_with_data(&header, &good_transactions, &good_uncles),
                engine,
                &bc,
            ),
            false,
        );

        header = good.clone();
        // will return `BlockError::TimestampOverflow` when timestamp > `i32::max_value()`
        header.set_timestamp(i32::max_value() as u64);
        check_fail_timestamp(
            basic_test(
                &create_test_block_with_data(&header, &good_transactions, &good_uncles),
                engine,
            ),
            false,
        );

        header = good.clone();
        header.set_timestamp(
            SystemTime::now()
                .duration_since(UNIX_EPOCH)
                .unwrap()
                .as_secs()
                + 20,
        );
        check_fail_timestamp(
            basic_test(
                &create_test_block_with_data(&header, &good_transactions, &good_uncles),
                engine,
            ),
            true,
        );

        header = good.clone();
        header.set_timestamp(
            SystemTime::now()
                .duration_since(UNIX_EPOCH)
                .unwrap()
                .as_secs()
                + 10,
        );
        header.set_uncles_hash(good_uncles_hash.clone());
        header.set_transactions_root(good_transactions_root.clone());
        check_ok(basic_test(
            &create_test_block_with_data(&header, &good_transactions, &good_uncles),
            engine,
        ));

        header = good.clone();
        header.set_number(9);
        check_fail(
            family_test(
                &create_test_block_with_data(&header, &good_transactions, &good_uncles),
                engine,
                &bc,
            ),
            InvalidNumber(Mismatch {
                expected: parent.number() + 1,
                found: header.number(),
            }),
        );

        header = good.clone();
        let mut bad_uncles = good_uncles.clone();
        bad_uncles.push(good_uncle1.clone());
        check_fail(
            family_test(
                &create_test_block_with_data(&header, &good_transactions, &bad_uncles),
                engine,
                &bc,
            ),
            TooManyUncles(OutOfBounds {
                max: Some(engine.maximum_uncle_count(header.number())),
                min: None,
                found: bad_uncles.len(),
            }),
        );

        header = good.clone();
        bad_uncles = vec![good_uncle1.clone(), good_uncle1.clone()];
        check_fail(
            family_test(
                &create_test_block_with_data(&header, &good_transactions, &bad_uncles),
                engine,
                &bc,
            ),
            DuplicateUncle(good_uncle1.hash()),
        );

        header = good.clone();
        header.set_gas_limit(0.into());
        header.set_difficulty(
            "0000000000000000000000000000000000000000000000000000000000020000"
                .parse::<U256>()
                .unwrap(),
        );
        match family_test(&create_test_block(&header), engine, &bc) {
            Err(Error(ErrorKind::Block(InvalidGasLimit(_)), _)) => {}
            Err(_) => {
                panic!("should be invalid difficulty fail");
            }
            _ => {
                panic!("Should be error, got Ok");
            }
        }

        // TODO: some additional uncle checks
    }

    #[test]
    fn dust_protection() {
        use engines::NullEngine;
        use ethkey::{Generator, Random};
        use machine::EthereumMachine;
        use types::transaction::{Action, Transaction};

        let mut params = CommonParams::default();
        params.dust_protection_transition = 0;
        params.nonce_cap_increment = 2;

        let mut header = Header::default();
        header.set_number(1);

        let keypair = Random.generate().unwrap();
        let bad_transactions: Vec<_> = (0..3)
            .map(|i| {
                Transaction {
                    action: Action::Create,
                    value: U256::zero(),
                    data: Vec::new(),
                    gas: 0.into(),
                    gas_price: U256::zero(),
                    nonce: i.into(),
                }
                .sign(keypair.secret(), None)
            })
            .collect();

        let good_transactions = [bad_transactions[0].clone(), bad_transactions[1].clone()];

        let machine = EthereumMachine::regular(params, BTreeMap::new());
        let engine = NullEngine::new(Default::default(), machine);
        check_fail(
            unordered_test(
                &create_test_block_with_data(&header, &bad_transactions, &[]),
                &engine,
            ),
            TooManyTransactions(keypair.address()),
        );
        unordered_test(
            &create_test_block_with_data(&header, &good_transactions, &[]),
            &engine,
        )
        .unwrap();
    }
}