// makeCurrent creates a new environment for the current cycle.
func (self *worker) makeCurrent(parent *types.Block, header *types.Header) {
	state := state.New(parent.Root(), self.eth.ChainDb())
	work := &Work{
		state:     state,
		ancestors: set.New(),
		family:    set.New(),
		uncles:    set.New(),
		header:    header,
		coinbase:  state.GetOrNewStateObject(self.coinbase),
		createdAt: time.Now(),
	}

	// when 08 is processed ancestors contain 07 (quick block)
	for _, ancestor := range self.chain.GetBlocksFromHash(parent.Hash(), 7) {
		for _, uncle := range ancestor.Uncles() {
			work.family.Add(uncle.Hash())
		}
		work.family.Add(ancestor.Hash())
		work.ancestors.Add(ancestor.Hash())
	}
	accounts, _ := self.eth.AccountManager().Accounts()

	// Keep track of transactions which return errors so they can be removed
	work.remove = set.New()
	work.tcount = 0
	work.ignoredTransactors = set.New()
	work.lowGasTransactors = set.New()
	work.ownedAccounts = accountAddressesSet(accounts)
	if self.current != nil {
		work.localMinedBlocks = self.current.localMinedBlocks
	}
	self.current = work
}

func (self *Filter) bloomFilter(block *types.Block) bool {
	if len(self.address) > 0 {
		var included bool
		for _, addr := range self.address {
			if types.BloomLookup(block.Bloom(), addr) {
				included = true
				break
			}
		}

		if !included {
			return false
		}
	}

	for _, sub := range self.topics {
		var included bool
		for _, topic := range sub {
			if (topic == common.Hash{}) || types.BloomLookup(block.Bloom(), topic) {
				included = true
				break
			}
		}
		if !included {
			return false
		}
	}

	return true
}

// SendNewBlock propagates an entire block to a remote peer.
func (p *peer) SendNewBlock(block *types.Block, td *big.Int) error {
	propBlockOutPacketsMeter.Mark(1)
	propBlockOutTrafficMeter.Mark(block.Size().Int64())

	p.knownBlocks.Add(block.Hash())
	return p2p.Send(p.rw, NewBlockMsg, []interface{}{block, td})
}

func (self *SQLDB) DeleteBlock(block *types.Block) {
	query := `DELETE FROM blocks WHERE number = ?`
	_, err := self.db.Exec(query, block.Number().Uint64())
	if err != nil {
		glog.V(logger.Error).Infoln("Error creating SQL tables", err, query)
	}
}

func blockRecovery(ctx *cli.Context) {
	utils.CheckLegalese(ctx.GlobalString(utils.DataDirFlag.Name))

	arg := ctx.Args().First()
	if len(ctx.Args()) < 1 && len(arg) > 0 {
		glog.Fatal("recover requires block number or hash")
	}

	cfg := utils.MakeEthConfig(ClientIdentifier, nodeNameVersion, ctx)
	utils.CheckLegalese(cfg.DataDir)

	blockDb, err := ethdb.NewLDBDatabase(filepath.Join(cfg.DataDir, "blockchain"), cfg.DatabaseCache)
	if err != nil {
		glog.Fatalln("could not open db:", err)
	}

	var block *types.Block
	if arg[0] == '#' {
		block = core.GetBlockByNumber(blockDb, common.String2Big(arg[1:]).Uint64())
	} else {
		block = core.GetBlockByHash(blockDb, common.HexToHash(arg))
	}

	if block == nil {
		glog.Fatalln("block not found. Recovery failed")
	}

	err = core.WriteHead(blockDb, block)
	if err != nil {
		glog.Fatalln("block write err", err)
	}
	glog.Infof("Recovery succesful. New HEAD %x\n", block.Hash())
}

func (bc *ChainManager) removeBlock(block *types.Block) {
	if bc.sqlDB != nil {
		bc.sqlDB.DeleteBlock(block)
	}

	bc.chainDb.Delete(append(blockHashPre, block.Hash().Bytes()...))
}

// enqueue schedules a new future import operation, if the block to be imported
// has not yet been seen.
func (f *Fetcher) enqueue(peer string, block *types.Block) {
	hash := block.Hash()

	// Ensure the peer isn't DOSing us
	count := f.queues[peer] + 1
	if count > blockLimit {
		glog.V(logger.Debug).Infof("Peer %s: discarded block #%d [%x], exceeded allowance (%d)", peer, block.NumberU64(), hash.Bytes()[:4], blockLimit)
		return
	}
	// Discard any past or too distant blocks
	if dist := int64(block.NumberU64()) - int64(f.chainHeight()); dist < -maxUncleDist || dist > maxQueueDist {
		glog.V(logger.Debug).Infof("Peer %s: discarded block #%d [%x], distance %d", peer, block.NumberU64(), hash.Bytes()[:4], dist)
		discardMeter.Mark(1)
		return
	}
	// Schedule the block for future importing
	if _, ok := f.queued[hash]; !ok {
		op := &inject{
			origin: peer,
			block:  block,
		}
		f.queues[peer] = count
		f.queued[hash] = op
		f.queue.Push(op, -float32(block.NumberU64()))

		if glog.V(logger.Debug) {
			glog.Infof("Peer %s: queued block #%d [%x], total %v", peer, block.NumberU64(), hash.Bytes()[:4], f.queue.Size())
		}
	}
}

// WriteCanonNumber writes the canonical hash for the given block
func WriteCanonNumber(db common.Database, block *types.Block) error {
	key := append(blockNumPre, block.Number().Bytes()...)
	err := db.Put(key, block.Hash().Bytes())
	if err != nil {
		return err
	}
	return nil
}

// CalcTD computes the total difficulty of block.
func CalcTD(block, parent *types.Block) *big.Int {
	if parent == nil {
		return block.Difficulty()
	}
	d := block.Difficulty()
	d.Add(d, parent.Td)
	return d
}

// GetLogs returns the logs of the given block. This method is using a two step approach
// where it tries to get it from the (updated) method which gets them from the receipts or
// the depricated way by re-processing the block.
func (sm *BlockProcessor) GetLogs(block *types.Block) (logs state.Logs, err error) {
	receipts := GetBlockReceipts(sm.chainDb, block.Hash())
	// coalesce logs
	for _, receipt := range receipts {
		logs = append(logs, receipt.Logs()...)
	}
	return logs, nil
}

func (self *ChainManager) GetUnclesInChain(block *types.Block, length int) (uncles []*types.Header) {
	for i := 0; block != nil && i < length; i++ {
		uncles = append(uncles, block.Uncles()...)
		block = self.GetBlock(block.ParentHash())
	}

	return
}

// WriteHead force writes the current head
func WriteHead(db common.Database, block *types.Block) error {
	err := WriteCanonNumber(db, block)
	if err != nil {
		return err
	}
	err = db.Put([]byte("LastBlock"), block.Hash().Bytes())
	if err != nil {
		return err
	}
	return nil
}

// BroadcastBlock will either propagate a block to a subset of it's peers, or
// will only announce it's availability (depending what's requested).
func (pm *ProtocolManager) BroadcastBlock(block *types.Block, propagate bool) {
	hash := block.Hash()
	peers := pm.peers.PeersWithoutBlock(hash)

	// If propagation is requested, send to a subset of the peer
	if propagate {
		// Calculate the TD of the block (it's not imported yet, so block.Td is not valid)
		var td *big.Int
		if parent := pm.chainman.GetBlock(block.ParentHash()); parent != nil {
			td = new(big.Int).Add(parent.Td, block.Difficulty())
		} else {
			glog.V(logger.Error).Infof("propagating dangling block #%d [%x]", block.NumberU64(), hash[:4])
			return
		}
		// Send the block to a subset of our peers
		transfer := peers[:int(math.Sqrt(float64(len(peers))))]
		for _, peer := range transfer {
			peer.SendNewBlock(block, td)
		}
		glog.V(logger.Detail).Infof("propagated block %x to %d peers in %v", hash[:4], len(transfer), time.Since(block.ReceivedAt))
	}
	// Otherwise if the block is indeed in out own chain, announce it
	if pm.chainman.HasBlock(hash) {
		for _, peer := range peers {
			peer.SendNewBlockHashes([]common.Hash{hash})
		}
		glog.V(logger.Detail).Infof("announced block %x to %d peers in %v", hash[:4], len(peers), time.Since(block.ReceivedAt))
	}
}

// CalcGasLimit computes the gas limit of the next block after parent.
// The result may be modified by the caller.
// This is miner strategy, not consensus protocol.
func CalcGasLimit(parent *types.Block) *big.Int {
	// contrib = (parentGasUsed * 3 / 2) / 1024
	contrib := new(big.Int).Mul(parent.GasUsed(), big.NewInt(3))
	contrib = contrib.Div(contrib, big.NewInt(2))
	contrib = contrib.Div(contrib, params.GasLimitBoundDivisor)

	// decay = parentGasLimit / 1024 -1
	decay := new(big.Int).Div(parent.GasLimit(), params.GasLimitBoundDivisor)
	decay.Sub(decay, big.NewInt(1))

	/*
		strategy: gasLimit of block-to-mine is set based on parent's
		gasUsed value.  if parentGasUsed > parentGasLimit * (2/3) then we
		increase it, otherwise lower it (or leave it unchanged if it's right
		at that usage) the amount increased/decreased depends on how far away
		from parentGasLimit * (2/3) parentGasUsed is.
	*/
	gl := new(big.Int).Sub(parent.GasLimit(), decay)
	gl = gl.Add(gl, contrib)
	gl.Set(common.BigMax(gl, params.MinGasLimit))

	// however, if we're now below the target (GenesisGasLimit) we increase the
	// limit as much as we can (parentGasLimit / 1024 -1)
	if gl.Cmp(params.GenesisGasLimit) < 0 {
		gl.Add(parent.GasLimit(), decay)
		gl.Set(common.BigMin(gl, params.GenesisGasLimit))
	}
	return gl
}

// makeChain creates a chain of n blocks starting at but not including
// parent. the returned hash chain is ordered head->parent.
func makeChain(n int, seed byte, parent *types.Block) ([]common.Hash, map[common.Hash]*types.Block) {
	blocks := core.GenerateChain(parent, testdb, n, func(i int, gen *core.BlockGen) {
		gen.SetCoinbase(common.Address{seed})
	})
	hashes := make([]common.Hash, n+1)
	hashes[len(hashes)-1] = parent.Hash()
	blockm := make(map[common.Hash]*types.Block, n+1)
	blockm[parent.Hash()] = parent
	for i, b := range blocks {
		hashes[len(hashes)-i-2] = b.Hash()
		blockm[b.Hash()] = b
	}
	return hashes, blockm
}

func (self *BlockProcessor) ApplyTransactions(gp GasPool, statedb *state.StateDB, block *types.Block, txs types.Transactions, transientProcess bool) (types.Receipts, error) {
	var (
		receipts      types.Receipts
		totalUsedGas  = big.NewInt(0)
		err           error
		cumulativeSum = new(big.Int)
		header        = block.Header()
	)

	for i, tx := range txs {
		statedb.StartRecord(tx.Hash(), block.Hash(), i)

		receipt, txGas, err := self.ApplyTransaction(gp, statedb, header, tx, totalUsedGas, transientProcess)
		if err != nil {
			return nil, err
		}

		if err != nil {
			glog.V(logger.Core).Infoln("TX err:", err)
		}
		receipts = append(receipts, receipt)

		cumulativeSum.Add(cumulativeSum, new(big.Int).Mul(txGas, tx.GasPrice()))
	}

	if block.GasUsed().Cmp(totalUsedGas) != 0 {
		return nil, ValidationError(fmt.Sprintf("gas used error (%v / %v)", block.GasUsed(), totalUsedGas))
	}

	if transientProcess {
		go self.eventMux.Post(PendingBlockEvent{block, statedb.Logs()})
	}

	return receipts, err
}

func (bc *ChainManager) SetHead(head *types.Block) {
	bc.mu.Lock()
	defer bc.mu.Unlock()

	for block := bc.currentBlock; block != nil && block.Hash() != head.Hash(); block = bc.GetBlock(block.ParentHash()) {
		bc.removeBlock(block)
	}

	bc.cache, _ = lru.New(blockCacheLimit)
	bc.currentBlock = head
	bc.makeCache()

	bc.setTotalDifficulty(head.Td)
	bc.insert(head)
	bc.setLastState()
}

func (self *GasPriceOracle) processBlock(block *types.Block) {
	i := block.NumberU64()
	if i > self.lastProcessed {
		self.lastProcessed = i
	}

	lastBase := self.eth.GpoMinGasPrice
	bpl := self.blocks[i-1]
	if bpl != nil {
		lastBase = bpl.baseGasPrice
	}
	if lastBase == nil {
		return
	}

	var corr int
	lp := self.lowestPrice(block)
	if lp == nil {
		return
	}

	if lastBase.Cmp(lp) < 0 {
		corr = self.eth.GpobaseStepUp
	} else {
		corr = -self.eth.GpobaseStepDown
	}

	crand := int64(corr * (900 + rand.Intn(201)))
	newBase := new(big.Int).Mul(lastBase, big.NewInt(1000000+crand))
	newBase.Div(newBase, big.NewInt(1000000))

	if newBase.Cmp(self.minBase) < 0 {
		newBase = self.minBase
	}

	bpi := self.blocks[i]
	if bpi == nil {
		bpi = &blockPriceInfo{}
		self.blocks[i] = bpi
	}
	bpi.baseGasPrice = newBase
	self.lastBaseMutex.Lock()
	self.lastBase = newBase
	self.lastBaseMutex.Unlock()

	glog.V(logger.Detail).Infof("Processed block #%v, base price is %v\n", block.NumberU64(), newBase.Int64())
}

func makeChainWithDiff(genesis *types.Block, d []int, seed byte) []*types.Block {
	var chain []*types.Block
	for i, difficulty := range d {
		header := &types.Header{
			Coinbase:   common.Address{seed},
			Number:     big.NewInt(int64(i + 1)),
			Difficulty: big.NewInt(int64(difficulty)),
		}
		if i == 0 {
			header.ParentHash = genesis.Hash()
		} else {
			header.ParentHash = chain[i-1].Hash()
		}
		block := types.NewBlockWithHeader(header)
		chain = append(chain, block)
	}
	return chain
}

// PutBlockReceipts stores the block's transactions associated receipts
// and stores them by block hash in a single slice. This is required for
// forks and chain reorgs
func PutBlockReceipts(db common.Database, block *types.Block, receipts types.Receipts) error {
	rs := make([]*types.ReceiptForStorage, len(receipts))
	for i, receipt := range receipts {
		rs[i] = (*types.ReceiptForStorage)(receipt)
	}
	bytes, err := rlp.EncodeToBytes(rs)
	if err != nil {
		return err
	}

	hash := block.Hash()
	err = db.Put(append(blockReceiptsPre, hash[:]...), bytes)
	if err != nil {
		return err
	}

	return nil
}