// CalcPriority returns a transaction priority given a transaction and the sum
// of each of its input values multiplied by their age (# of confirmations).
// Thus, the final formula for the priority is:
// sum(inputValue * inputAge) / adjustedTxSize
func CalcPriority(tx *wire.MsgTx, utxoView *blockchain.UtxoViewpoint, nextBlockHeight int32) float64 {
	// In order to encourage spending multiple old unspent transaction
	// outputs thereby reducing the total set, don't count the constant
	// overhead for each input as well as enough bytes of the signature
	// script to cover a pay-to-script-hash redemption with a compressed
	// pubkey.  This makes additional inputs free by boosting the priority
	// of the transaction accordingly.  No more incentive is given to avoid
	// encouraging gaming future transactions through the use of junk
	// outputs.  This is the same logic used in the reference
	// implementation.
	//
	// The constant overhead for a txin is 41 bytes since the previous
	// outpoint is 36 bytes + 4 bytes for the sequence + 1 byte the
	// signature script length.
	//
	// A compressed pubkey pay-to-script-hash redemption with a maximum len
	// signature is of the form:
	// [OP_DATA_73 <73-byte sig> + OP_DATA_35 + {OP_DATA_33
	// <33 byte compresed pubkey> + OP_CHECKSIG}]
	//
	// Thus 1 + 73 + 1 + 1 + 33 + 1 = 110
	overhead := 0
	for _, txIn := range tx.TxIn {
		// Max inputs + size can't possibly overflow here.
		overhead += 41 + minInt(110, len(txIn.SignatureScript))
	}

	serializedTxSize := tx.SerializeSize()
	if overhead >= serializedTxSize {
		return 0.0
	}

	inputValueAge := calcInputValueAge(tx, utxoView, nextBlockHeight)
	return inputValueAge / float64(serializedTxSize-overhead)
}

// GetDoubleSpends takes a transaction and compares it with
// all transactions in the db.  It returns a slice of all txids in the db
// which are double spent by the received tx.
func CheckDoubleSpends(
	argTx *wire.MsgTx, txs []*wire.MsgTx) ([]*wire.ShaHash, error) {

	var dubs []*wire.ShaHash // slice of all double-spent txs
	argTxid := argTx.TxSha()

	for _, compTx := range txs {
		compTxid := compTx.TxSha()
		// check if entire tx is dup
		if argTxid.IsEqual(&compTxid) {
			return nil, fmt.Errorf("tx %s is dup", argTxid.String())
		}
		// not dup, iterate through inputs of argTx
		for _, argIn := range argTx.TxIn {
			// iterate through inputs of compTx
			for _, compIn := range compTx.TxIn {
				if OutPointsEqual(
					argIn.PreviousOutPoint, compIn.PreviousOutPoint) {
					// found double spend
					dubs = append(dubs, &compTxid)
					break // back to argIn loop
				}
			}
		}
	}
	return dubs, nil
}

// fetchTxDataByLoc returns several pieces of data regarding the given tx
// located by the block/offset/size location
func (db *LevelDb) fetchTxDataByLoc(blkHeight int32, txOff int, txLen int, txspent []byte) (rtx *wire.MsgTx, rblksha *wire.ShaHash, rheight int32, rtxspent []byte, err error) {
	var blksha *wire.ShaHash
	var blkbuf []byte

	blksha, blkbuf, err = db.getBlkByHeight(blkHeight)
	if err != nil {
		if err == leveldb.ErrNotFound {
			err = database.ErrTxShaMissing
		}
		return
	}

	//log.Trace("transaction %v is at block %v %v txoff %v, txlen %v\n",
	//	txsha, blksha, blkHeight, txOff, txLen)

	if len(blkbuf) < txOff+txLen {
		err = database.ErrTxShaMissing
		return
	}
	rbuf := bytes.NewReader(blkbuf[txOff : txOff+txLen])

	var tx wire.MsgTx
	err = tx.Deserialize(rbuf)
	if err != nil {
		log.Warnf("unable to decode tx block %v %v txoff %v txlen %v",
			blkHeight, blksha, txOff, txLen)
		return
	}

	return &tx, blksha, blkHeight, txspent, nil
}

// broadcastTx tries to send the transaction using an api that will broadcast
// a submitted transaction on behalf of the user.
//
// The transaction is broadcast to the bitcoin network using this API:
//    https://github.com/bitpay/insight-api
//
func broadcastTx(tx *wire.MsgTx) {
	buf := bytes.NewBuffer(make([]byte, 0, tx.SerializeSize()))
	tx.Serialize(buf)
	hexstr := hex.EncodeToString(buf.Bytes())

	url := "https://insight.bitpay.com/api/tx/send"
	contentType := "application/json"

	fmt.Printf("Sending transaction to: %s\n", url)
	sendTxJson := &sendTxJson{RawTx: hexstr}
	j, err := json.Marshal(sendTxJson)
	if err != nil {
		log.Fatal(fmt.Errorf("Broadcasting the tx failed: %v", err))
	}
	buf = bytes.NewBuffer(j)
	resp, err := http.Post(url, contentType, buf)
	if err != nil {
		log.Fatal(fmt.Errorf("Broadcasting the tx failed: %v", err))
	}

	b, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		log.Fatal(err)
	}

	fmt.Printf("The sending api responded with:\n%s\n", b)
}

// AbsorbTx absorbs money into wallet from a tx
func (t *TxStore) AbsorbTx(tx *wire.MsgTx) error {
	if tx == nil {
		return fmt.Errorf("Tried to add nil tx")
	}
	var hits uint32
	var acq int64
	// check if any of the tx's outputs match my adrs
	for i, out := range tx.TxOut { // in each output of tx
		for _, a := range t.Adrs { // compare to each adr we have
			// more correct would be to check for full script
			// contains could have false positive? (p2sh/p2pkh same hash ..?)
			if bytes.Contains(out.PkScript, a.ScriptAddress()) { // hit
				hits++
				acq += out.Value
				var newu Utxo
				newu.KeyIdx = a.KeyIdx
				newu.Txo = *out

				var newop wire.OutPoint
				newop.Hash = tx.TxSha()
				newop.Index = uint32(i)
				newu.Op = newop

				t.Utxos = append(t.Utxos, newu)
				break
			}
		}
	}
	log.Printf("%d hits, acquired %d", hits, acq)
	t.Sum += acq
	return nil
}

// dbFetchTx looks up the passed transaction hash in the transaction index and
// loads it from the database.
func dbFetchTx(dbTx database.Tx, hash *wire.ShaHash) (*wire.MsgTx, error) {
	// Look up the location of the transaction.
	blockRegion, err := dbFetchTxIndexEntry(dbTx, hash)
	if err != nil {
		return nil, err
	}
	if blockRegion == nil {
		return nil, fmt.Errorf("transaction %v not found", hash)
	}

	// Load the raw transaction bytes from the database.
	txBytes, err := dbTx.FetchBlockRegion(blockRegion)
	if err != nil {
		return nil, err
	}

	// Deserialize the transaction.
	var msgTx wire.MsgTx
	err = msgTx.Deserialize(bytes.NewReader(txBytes))
	if err != nil {
		return nil, err
	}

	return &msgTx, nil
}

// dumpHex dumps the raw bytes of a Bitcoin transaction to stdout. This is the
// format that Bitcoin wire's protocol accepts, so you could connect to a node,
// send them these bytes, and if the tx was valid, the node would forward the
// tx through the network.
func dumpHex(tx *wire.MsgTx) {
	buf := bytes.NewBuffer(make([]byte, 0, tx.SerializeSize()))
	tx.Serialize(buf)
	hexstr := hex.EncodeToString(buf.Bytes())
	fmt.Println("Here is your raw bitcoin transaction:")
	fmt.Println(hexstr)
}

// Receive waits for the response promised by the future and returns the
// found raw transactions.
func (r FutureSearchRawTransactionsResult) Receive() ([]*wire.MsgTx, error) {
	res, err := receiveFuture(r)
	if err != nil {
		return nil, err
	}

	// Unmarshal as an array of strings.
	var searchRawTxnsResult []string
	err = json.Unmarshal(res, &searchRawTxnsResult)
	if err != nil {
		return nil, err
	}

	// Decode and deserialize each transaction.
	msgTxns := make([]*wire.MsgTx, 0, len(searchRawTxnsResult))
	for _, hexTx := range searchRawTxnsResult {
		// Decode the serialized transaction hex to raw bytes.
		serializedTx, err := hex.DecodeString(hexTx)
		if err != nil {
			return nil, err
		}

		// Deserialize the transaction and add it to the result slice.
		var msgTx wire.MsgTx
		err = msgTx.Deserialize(bytes.NewReader(serializedTx))
		if err != nil {
			return nil, err
		}
		msgTxns = append(msgTxns, &msgTx)
	}

	return msgTxns, nil
}

// TestTxSerialize tests MsgTx serialize and deserialize.
func TestTxSerialize(t *testing.T) {
	noTx := wire.NewMsgTx()
	noTx.Version = 1
	noTxEncoded := []byte{
		0x01, 0x00, 0x00, 0x00, // Version
		0x00,                   // Varint for number of input transactions
		0x00,                   // Varint for number of output transactions
		0x00, 0x00, 0x00, 0x00, // Lock time
	}

	tests := []struct {
		in  *wire.MsgTx // Message to encode
		out *wire.MsgTx // Expected decoded message
		buf []byte      // Serialized data
	}{
		// No transactions.
		{
			noTx,
			noTx,
			noTxEncoded,
		},

		// Multiple transactions.
		{
			multiTx,
			multiTx,
			multiTxEncoded,
		},
	}

	t.Logf("Running %d tests", len(tests))
	for i, test := range tests {
		// Serialize the transaction.
		var buf bytes.Buffer
		err := test.in.Serialize(&buf)
		if err != nil {
			t.Errorf("Serialize #%d error %v", i, err)
			continue
		}
		if !bytes.Equal(buf.Bytes(), test.buf) {
			t.Errorf("Serialize #%d\n got: %s want: %s", i,
				spew.Sdump(buf.Bytes()), spew.Sdump(test.buf))
			continue
		}

		// Deserialize the transaction.
		var tx wire.MsgTx
		rbuf := bytes.NewReader(test.buf)
		err = tx.Deserialize(rbuf)
		if err != nil {
			t.Errorf("Deserialize #%d error %v", i, err)
			continue
		}
		if !reflect.DeepEqual(&tx, test.out) {
			t.Errorf("Deserialize #%d\n got: %s want: %s", i,
				spew.Sdump(&tx), spew.Sdump(test.out))
			continue
		}
	}
}

// TestTxSerializeErrors performs negative tests against wire encode and decode
// of MsgTx to confirm error paths work correctly.
func TestTxSerializeErrors(t *testing.T) {
	tests := []struct {
		in       *wire.MsgTx // Value to encode
		buf      []byte      // Serialized data
		max      int         // Max size of fixed buffer to induce errors
		writeErr error       // Expected write error
		readErr  error       // Expected read error
	}{
		// Force error in version.
		{multiTx, multiTxEncoded, 0, io.ErrShortWrite, io.EOF},
		// Force error in number of transaction inputs.
		{multiTx, multiTxEncoded, 4, io.ErrShortWrite, io.EOF},
		// Force error in transaction input previous block hash.
		{multiTx, multiTxEncoded, 5, io.ErrShortWrite, io.EOF},
		// Force error in transaction input previous block hash.
		{multiTx, multiTxEncoded, 5, io.ErrShortWrite, io.EOF},
		// Force error in transaction input previous block output index.
		{multiTx, multiTxEncoded, 37, io.ErrShortWrite, io.EOF},
		// Force error in transaction input signature script length.
		{multiTx, multiTxEncoded, 41, io.ErrShortWrite, io.EOF},
		// Force error in transaction input signature script.
		{multiTx, multiTxEncoded, 42, io.ErrShortWrite, io.EOF},
		// Force error in transaction input sequence.
		{multiTx, multiTxEncoded, 49, io.ErrShortWrite, io.EOF},
		// Force error in number of transaction outputs.
		{multiTx, multiTxEncoded, 53, io.ErrShortWrite, io.EOF},
		// Force error in transaction output value.
		{multiTx, multiTxEncoded, 54, io.ErrShortWrite, io.EOF},
		// Force error in transaction output pk script length.
		{multiTx, multiTxEncoded, 62, io.ErrShortWrite, io.EOF},
		// Force error in transaction output pk script.
		{multiTx, multiTxEncoded, 63, io.ErrShortWrite, io.EOF},
		// Force error in transaction output lock time.
		{multiTx, multiTxEncoded, 130, io.ErrShortWrite, io.EOF},
	}

	t.Logf("Running %d tests", len(tests))
	for i, test := range tests {
		// Serialize the transaction.
		w := newFixedWriter(test.max)
		err := test.in.Serialize(w)
		if err != test.writeErr {
			t.Errorf("Serialize #%d wrong error got: %v, want: %v",
				i, err, test.writeErr)
			continue
		}

		// Deserialize the transaction.
		var tx wire.MsgTx
		r := newFixedReader(test.max, test.buf)
		err = tx.Deserialize(r)
		if err != test.readErr {
			t.Errorf("Deserialize #%d wrong error got: %v, want: %v",
				i, err, test.readErr)
			continue
		}
	}
}

// TestCalcSignatureHash runs the Bitcoin Core signature hash calculation tests
// in sighash.json.
// https://github.com/bitcoin/bitcoin/blob/master/src/test/data/sighash.json
func TestCalcSignatureHash(t *testing.T) {
	file, err := ioutil.ReadFile("data/sighash.json")
	if err != nil {
		t.Errorf("TestCalcSignatureHash: %v\n", err)
		return
	}

	var tests [][]interface{}
	err = json.Unmarshal(file, &tests)
	if err != nil {
		t.Errorf("TestCalcSignatureHash couldn't Unmarshal: %v\n",
			err)
		return
	}

	for i, test := range tests {
		if i == 0 {
			// Skip first line -- contains comments only.
			continue
		}
		if len(test) != 5 {
			t.Fatalf("TestCalcSignatureHash: Test #%d has "+
				"wrong length.", i)
		}
		var tx wire.MsgTx
		rawTx, _ := hex.DecodeString(test[0].(string))
		err := tx.Deserialize(bytes.NewReader(rawTx))
		if err != nil {
			t.Errorf("TestCalcSignatureHash failed test #%d: "+
				"Failed to parse transaction: %v", i, err)
			continue
		}

		subScript, _ := hex.DecodeString(test[1].(string))
		parsedScript, err := parseScript(subScript)
		if err != nil {
			t.Errorf("TestCalcSignatureHash failed test #%d: "+
				"Failed to parse sub-script: %v", i, err)
			continue
		}

		hashType := SigHashType(testVecF64ToUint32(test[3].(float64)))
		hash := calcSignatureHash(parsedScript, hashType, &tx,
			int(test[2].(float64)))

		expectedHash, _ := chainhash.NewHashFromStr(test[4].(string))
		if !bytes.Equal(hash, expectedHash[:]) {
			t.Errorf("TestCalcSignatureHash failed test #%d: "+
				"Signature hash mismatch.", i)
		}
	}
}

func newCoinBase(outputValues ...int64) *wire.MsgTx {
	tx := wire.MsgTx{
		TxIn: []*wire.TxIn{
			&wire.TxIn{
				PreviousOutPoint: wire.OutPoint{Index: ^uint32(0)},
			},
		},
	}
	for _, val := range outputValues {
		tx.TxOut = append(tx.TxOut, &wire.TxOut{Value: val})
	}
	return &tx
}

func spendOutput(txHash *chainhash.Hash, index uint32, outputValues ...int64) *wire.MsgTx {
	tx := wire.MsgTx{
		TxIn: []*wire.TxIn{
			&wire.TxIn{
				PreviousOutPoint: wire.OutPoint{Hash: *txHash, Index: index},
			},
		},
	}
	for _, val := range outputValues {
		tx.TxOut = append(tx.TxOut, &wire.TxOut{Value: val})
	}
	return &tx
}

// addChange adds a new output with the given amount and address, and
// randomizes the index (and returns it) of the newly added output.
func addChange(msgtx *wire.MsgTx, change btcutil.Amount, changeAddr btcutil.Address) (int, error) {
	pkScript, err := txscript.PayToAddrScript(changeAddr)
	if err != nil {
		return 0, fmt.Errorf("cannot create txout script: %s", err)
	}
	msgtx.AddTxOut(wire.NewTxOut(int64(change), pkScript))

	// Randomize index of the change output.
	rng := badrand.New(badrand.NewSource(time.Now().UnixNano()))
	r := rng.Int31n(int32(len(msgtx.TxOut))) // random index
	c := len(msgtx.TxOut) - 1                // change index
	msgtx.TxOut[r], msgtx.TxOut[c] = msgtx.TxOut[c], msgtx.TxOut[r]
	return int(r), nil
}

// NewTxFromReader returns a new instance of a bitcoin transaction given a
// Reader to deserialize the transaction.  See Tx.
func NewTxFromReader(r io.Reader) (*Tx, error) {
	// Deserialize the bytes into a MsgTx.
	var msgTx wire.MsgTx
	err := msgTx.Deserialize(r)
	if err != nil {
		return nil, err
	}

	t := Tx{
		msgTx:   &msgTx,
		txIndex: TxIndexUnknown,
	}
	return &t, nil
}

// SendRawTransactionAsync returns an instance of a type that can be used to get
// the result of the RPC at some future time by invoking the Receive function on
// the returned instance.
//
// See SendRawTransaction for the blocking version and more details.
func (c *Client) SendRawTransactionAsync(tx *wire.MsgTx, allowHighFees bool) FutureSendRawTransactionResult {
	txHex := ""
	if tx != nil {
		// Serialize the transaction and convert to hex string.
		buf := bytes.NewBuffer(make([]byte, 0, tx.SerializeSize()))
		if err := tx.Serialize(buf); err != nil {
			return newFutureError(err)
		}
		txHex = hex.EncodeToString(buf.Bytes())
	}

	cmd := btcjson.NewSendRawTransactionCmd(txHex, &allowHighFees)
	return c.sendCmd(cmd)
}

// SignRawTransaction2Async returns an instance of a type that can be used to
// get the result of the RPC at some future time by invoking the Receive
// function on the returned instance.
//
// See SignRawTransaction2 for the blocking version and more details.
func (c *Client) SignRawTransaction2Async(tx *wire.MsgTx, inputs []btcjson.RawTxInput) FutureSignRawTransactionResult {
	txHex := ""
	if tx != nil {
		// Serialize the transaction and convert to hex string.
		buf := bytes.NewBuffer(make([]byte, 0, tx.SerializeSize()))
		if err := tx.Serialize(buf); err != nil {
			return newFutureError(err)
		}
		txHex = hex.EncodeToString(buf.Bytes())
	}

	cmd := btcjson.NewSignRawTransactionCmd(txHex, &inputs, nil, nil)
	return c.sendCmd(cmd)
}

func NewTransactionRecord(msg *wire.MsgTx, ra *net.TCPAddr,
	la *net.TCPAddr) *TransactionRecord {
	record := &TransactionRecord{
		Record: Record{
			stamp: time.Now(),
			ra:    ra,
			la:    la,
			cmd:   msg.Command(),
		},

		details: NewDetailsRecord(msg),
	}

	return record
}

// NewTxRecordFromMsgTx creates a new transaction record that may be inserted
// into the store.
func NewTxRecordFromMsgTx(msgTx *wire.MsgTx, received time.Time) (*TxRecord, error) {
	buf := bytes.NewBuffer(make([]byte, 0, msgTx.SerializeSize()))
	err := msgTx.Serialize(buf)
	if err != nil {
		str := "failed to serialize transaction"
		return nil, storeError(ErrInput, str, err)
	}
	rec := &TxRecord{
		MsgTx:        *msgTx,
		Received:     received,
		SerializedTx: buf.Bytes(),
	}
	copy(rec.Hash[:], wire.DoubleSha256(rec.SerializedTx))
	return rec, nil
}

// addHTLC...
// NOTE: This MUST be called with stateMtx held.
func (lc *LightningChannel) addHTLC(ourCommitTx, theirCommitTx *wire.MsgTx,
	paymentDesc *PaymentDescriptor) error {

	// If the HTLC is going to us, then we're the sender, otherwise they
	// are.
	var senderKey, receiverKey *btcec.PublicKey
	var senderRevocation, receiverRevocation []byte
	if paymentDesc.PayToUs {
		receiverKey = lc.channelState.OurCommitKey.PubKey()
		receiverRevocation = paymentDesc.OurRevocation[:]
		senderKey = lc.channelState.TheirCommitKey
		senderRevocation = paymentDesc.TheirRevocation[:]
	} else {
		senderKey = lc.channelState.OurCommitKey.PubKey()
		senderRevocation = paymentDesc.OurRevocation[:]
		receiverKey = lc.channelState.TheirCommitKey
		receiverRevocation = paymentDesc.TheirRevocation[:]
	}

	// Generate the proper redeem scripts for the HTLC output for both the
	// sender and the receiver.
	timeout := paymentDesc.Timeout
	rHash := paymentDesc.RHash
	delay := lc.channelState.CsvDelay
	senderPKScript, err := senderHTLCScript(timeout, delay, senderKey,
		receiverKey, senderRevocation[:], rHash[:])
	if err != nil {
		return nil
	}
	receiverPKScript, err := receiverHTLCScript(timeout, delay, senderKey,
		receiverKey, receiverRevocation[:], rHash[:])
	if err != nil {
		return nil
	}

	// Now that we have the redeem scripts, create the P2SH public key
	// script for each.
	senderP2SH, err := scriptHashPkScript(senderPKScript)
	if err != nil {
		return nil
	}
	receiverP2SH, err := scriptHashPkScript(receiverPKScript)
	if err != nil {
		return nil
	}

	// Add the new HTLC outputs to the respective commitment transactions.
	amountPending := int64(paymentDesc.Value)
	if paymentDesc.PayToUs {
		ourCommitTx.AddTxOut(wire.NewTxOut(amountPending, receiverP2SH))
		theirCommitTx.AddTxOut(wire.NewTxOut(amountPending, senderP2SH))
	} else {
		ourCommitTx.AddTxOut(wire.NewTxOut(amountPending, senderP2SH))
		theirCommitTx.AddTxOut(wire.NewTxOut(amountPending, receiverP2SH))
	}

	return nil
}