// queueTx will queue an unknown transaction
func (self *TxPool) queueTx(hash common.Hash, tx *types.Transaction) {
	from, _ := tx.From() // already validated
	if self.queue[from] == nil {
		self.queue[from] = make(map[common.Hash]*types.Transaction)
	}
	self.queue[from][hash] = tx
}

// sign is a helper function that signs a transaction with the private key of the given address.
func (s *PublicTransactionPoolAPI) sign(address common.Address, tx *types.Transaction) (*types.Transaction, error) {
	acc := accounts.Account{address}
	signature, err := s.am.Sign(acc, tx.SigHash().Bytes())
	if err != nil {
		return nil, err
	}
	return tx.WithSignature(signature)
}

// AddTx adds a transaction to the generated block. If no coinbase has
// been set, the block's coinbase is set to the zero address.
//
// AddTx panics if the transaction cannot be executed. In addition to
// the protocol-imposed limitations (gas limit, etc.), there are some
// further limitations on the content of transactions that can be
// added. Notably, contract code relying on the BLOCKHASH instruction
// will panic during execution.
func (b *BlockGen) AddTx(tx *types.Transaction) {
	if b.gasPool == nil {
		b.SetCoinbase(common.Address{})
	}
	b.statedb.StartRecord(tx.Hash(), common.Hash{}, len(b.txs))
	receipt, _, _, err := ApplyTransaction(nil, b.gasPool, b.statedb, b.header, tx, b.header.GasUsed)
	if err != nil {
		panic(err)
	}
	b.txs = append(b.txs, tx)
	b.receipts = append(b.receipts, receipt)
}

// SendTransaction will create a transaction for the given transaction argument, sign it and submit it to the
// transaction pool.
func (s *PublicTransactionPoolAPI) SendTransaction(args SendTxArgs) (common.Hash, error) {
	if args.Gas == nil {
		args.Gas = rpc.NewHexNumber(defaultGas)
	}
	if args.GasPrice == nil {
		args.GasPrice = rpc.NewHexNumber(defaultGasPrice)
	}
	if args.Value == nil {
		args.Value = rpc.NewHexNumber(0)
	}

	s.txMu.Lock()
	defer s.txMu.Unlock()

	if args.Nonce == nil {
		args.Nonce = rpc.NewHexNumber(s.txPool.State().GetNonce(args.From))
	}

	var tx *types.Transaction
	contractCreation := (args.To == common.Address{})

	if contractCreation {
		tx = types.NewContractCreation(args.Nonce.Uint64(), args.Value.BigInt(), args.Gas.BigInt(), args.GasPrice.BigInt(), common.FromHex(args.Data))
	} else {
		tx = types.NewTransaction(args.Nonce.Uint64(), args.To, args.Value.BigInt(), args.Gas.BigInt(), args.GasPrice.BigInt(), common.FromHex(args.Data))
	}

	signedTx, err := s.sign(args.From, tx)
	if err != nil {
		return common.Hash{}, err
	}

	s.txPool.SetLocal(signedTx)
	if err := s.txPool.Add(signedTx); err != nil {
		return common.Hash{}, nil
	}

	if contractCreation {
		addr := crypto.CreateAddress(args.From, args.Nonce.Uint64())
		glog.V(logger.Info).Infof("Tx(%s) created: %s\n", signedTx.Hash().Hex(), addr.Hex())
	} else {
		glog.V(logger.Info).Infof("Tx(%s) to: %s\n", signedTx.Hash().Hex(), tx.To().Hex())
	}

	return signedTx.Hash(), nil
}

// addTx will add a transaction to the pending (processable queue) list of transactions
func (pool *TxPool) addTx(hash common.Hash, addr common.Address, tx *types.Transaction) {
	// init delayed since tx pool could have been started before any state sync
	if pool.pendingState == nil {
		pool.resetState()
	}

	if _, ok := pool.pending[hash]; !ok {
		pool.pending[hash] = tx

		// Increment the nonce on the pending state. This can only happen if
		// the nonce is +1 to the previous one.
		pool.pendingState.SetNonce(addr, tx.Nonce()+1)
		// Notify the subscribers. This event is posted in a goroutine
		// because it's possible that somewhere during the post "Remove transaction"
		// gets called which will then wait for the global tx pool lock and deadlock.
		go pool.eventMux.Post(TxPreEvent{tx})
	}
}

// validate and queue transactions.
func (self *TxPool) add(tx *types.Transaction) error {
	hash := tx.Hash()

	if self.pending[hash] != nil {
		return fmt.Errorf("Known transaction (%x)", hash[:4])
	}
	err := self.validateTx(tx)
	if err != nil {
		return err
	}
	self.queueTx(hash, tx)

	if glog.V(logger.Debug) {
		var toname string
		if to := tx.To(); to != nil {
			toname = common.Bytes2Hex(to[:4])
		} else {
			toname = "[NEW_CONTRACT]"
		}
		// we can ignore the error here because From is
		// verified in ValidateTransaction.
		f, _ := tx.From()
		from := common.Bytes2Hex(f[:4])
		glog.Infof("(t) %x => %s (%v) %x\n", from, toname, tx.Value, hash)
	}

	return nil
}

// ApplyTransaction attemps to apply a transaction to the given state database
// and uses the input parameters for its environment.
//
// ApplyTransactions returns the generated receipts and vm logs during the
// execution of the state transition phase.
func ApplyTransaction(bc *BlockChain, gp *GasPool, statedb *state.StateDB, header *types.Header, tx *types.Transaction, usedGas *big.Int) (*types.Receipt, vm.Logs, *big.Int, error) {
	_, gas, err := ApplyMessage(NewEnv(statedb, bc, tx, header), tx, gp)
	if err != nil {
		return nil, nil, nil, err
	}

	// Update the state with pending changes
	usedGas.Add(usedGas, gas)
	receipt := types.NewReceipt(statedb.IntermediateRoot().Bytes(), usedGas)
	receipt.TxHash = tx.Hash()
	receipt.GasUsed = new(big.Int).Set(gas)
	if MessageCreatesContract(tx) {
		from, _ := tx.From()
		receipt.ContractAddress = crypto.CreateAddress(from, tx.Nonce())
	}

	logs := statedb.GetLogs(tx.Hash())
	receipt.Logs = logs
	receipt.Bloom = types.CreateBloom(types.Receipts{receipt})

	glog.V(logger.Debug).Infoln(receipt)

	return receipt, logs, gas, err
}

// validateTx checks whether a transaction is valid according
// to the consensus rules.
func (pool *TxPool) validateTx(tx *types.Transaction) error {
	// Validate sender
	var (
		from common.Address
		err  error
	)

	local := pool.localTx.contains(tx.Hash())
	// Drop transactions under our own minimal accepted gas price
	if !local && pool.minGasPrice.Cmp(tx.GasPrice()) > 0 {
		return ErrCheap
	}

	// Validate the transaction sender and it's sig. Throw
	// if the from fields is invalid.
	if from, err = tx.From(); err != nil {
		return ErrInvalidSender
	}

	// Make sure the account exist. Non existent accounts
	// haven't got funds and well therefor never pass.
	currentState, err := pool.currentState()
	if err != nil {
		return err
	}
	if !currentState.HasAccount(from) {
		return ErrNonExistentAccount
	}

	// Last but not least check for nonce errors
	if currentState.GetNonce(from) > tx.Nonce() {
		return ErrNonce
	}

	// Check the transaction doesn't exceed the current
	// block limit gas.
	if pool.gasLimit().Cmp(tx.Gas()) < 0 {
		return ErrGasLimit
	}

	// Transactions can't be negative. This may never happen
	// using RLP decoded transactions but may occur if you create
	// a transaction using the RPC for example.
	if tx.Value().Cmp(common.Big0) < 0 {
		return ErrNegativeValue
	}

	// Transactor should have enough funds to cover the costs
	// cost == V + GP * GL
	if currentState.GetBalance(from).Cmp(tx.Cost()) < 0 {
		return ErrInsufficientFunds
	}

	// Should supply enough intrinsic gas
	if tx.Gas().Cmp(IntrinsicGas(tx.Data())) < 0 {
		return ErrIntrinsicGas
	}

	return nil
}

// SetLocal marks a transaction as local, skipping gas price
//  check against local miner minimum in the future
func (pool *TxPool) SetLocal(tx *types.Transaction) {
	pool.mu.Lock()
	defer pool.mu.Unlock()
	pool.localTx.add(tx.Hash())
}

// Transact forms a transaction from the given arguments and submits it to the
// transactio pool for execution.
func (be *registryAPIBackend) Transact(fromStr, toStr, nonceStr, valueStr, gasStr, gasPriceStr, codeStr string) (string, error) {
	if len(toStr) > 0 && toStr != "0x" && !common.IsHexAddress(toStr) {
		return "", errors.New("invalid address")
	}

	var (
		from             = common.HexToAddress(fromStr)
		to               = common.HexToAddress(toStr)
		value            = common.Big(valueStr)
		gas              *big.Int
		price            *big.Int
		data             []byte
		contractCreation bool
	)

	if len(gasStr) == 0 {
		gas = big.NewInt(90000)
	} else {
		gas = common.Big(gasStr)
	}

	if len(gasPriceStr) == 0 {
		price = big.NewInt(10000000000000)
	} else {
		price = common.Big(gasPriceStr)
	}

	data = common.FromHex(codeStr)
	if len(toStr) == 0 {
		contractCreation = true
	}

	nonce := be.txPool.State().GetNonce(from)
	if len(nonceStr) != 0 {
		nonce = common.Big(nonceStr).Uint64()
	}

	var tx *types.Transaction
	if contractCreation {
		tx = types.NewContractCreation(nonce, value, gas, price, data)
	} else {
		tx = types.NewTransaction(nonce, to, value, gas, price, data)
	}

	acc := accounts.Account{from}
	signature, err := be.am.Sign(acc, tx.SigHash().Bytes())
	if err != nil {
		return "", err
	}
	signedTx, err := tx.WithSignature(signature)
	if err != nil {
		return "", err
	}

	be.txPool.SetLocal(signedTx)
	if err := be.txPool.Add(signedTx); err != nil {
		return "", nil
	}

	if contractCreation {
		addr := crypto.CreateAddress(from, nonce)
		glog.V(logger.Info).Infof("Tx(%s) created: %s\n", signedTx.Hash().Hex(), addr.Hex())
	} else {
		glog.V(logger.Info).Infof("Tx(%s) to: %s\n", signedTx.Hash().Hex(), tx.To().Hex())
	}

	return signedTx.Hash().Hex(), nil
}

// SendRawTransaction will add the signed transaction to the transaction pool.
// The sender is responsible for signing the transaction and using the correct nonce.
func (s *PublicTransactionPoolAPI) SendRawTransaction(encodedTx string) (string, error) {
	tx := new(types.Transaction)
	if err := rlp.DecodeBytes(common.FromHex(encodedTx), tx); err != nil {
		return "", err
	}

	s.txPool.SetLocal(tx)
	if err := s.txPool.Add(tx); err != nil {
		return "", err
	}

	if tx.To() == nil {
		from, err := tx.From()
		if err != nil {
			return "", err
		}
		addr := crypto.CreateAddress(from, tx.Nonce())
		glog.V(logger.Info).Infof("Tx(%x) created: %x\n", tx.Hash(), addr)
	} else {
		glog.V(logger.Info).Infof("Tx(%x) to: %x\n", tx.Hash(), tx.To())
	}

	return tx.Hash().Hex(), nil
}

// newRPCPendingTransaction returns a pending transaction that will serialize to the RPC representation
func newRPCPendingTransaction(tx *types.Transaction) *RPCTransaction {
	from, _ := tx.From()

	return &RPCTransaction{
		From:     from,
		Gas:      rpc.NewHexNumber(tx.Gas()),
		GasPrice: rpc.NewHexNumber(tx.GasPrice()),
		Hash:     tx.Hash(),
		Input:    fmt.Sprintf("0x%x", tx.Data()),
		Nonce:    rpc.NewHexNumber(tx.Nonce()),
		To:       tx.To(),
		Value:    rpc.NewHexNumber(tx.Value()),
	}
}

func newTx(t *types.Transaction) *Tx {
	from, _ := t.From()
	return &Tx{
		tx:       t,
		To:       t.To(),
		From:     from,
		Value:    rpc.NewHexNumber(t.Value()),
		Nonce:    rpc.NewHexNumber(t.Nonce()),
		Data:     "0x" + common.Bytes2Hex(t.Data()),
		GasLimit: rpc.NewHexNumber(t.Gas()),
		GasPrice: rpc.NewHexNumber(t.GasPrice()),
		Hash:     t.Hash(),
	}
}