// PushGetBlocksMsg sends a getblocks message for the provided block locator
// and stop hash.  It will ignore back-to-back duplicate requests.
func (p *peer) PushGetBlocksMsg(locator btcchain.BlockLocator, stopHash *btcwire.ShaHash) error {
	// Extract the begin hash from the block locator, if one was specified,
	// to use for filtering duplicate getblocks requests.
	// request.
	var beginHash *btcwire.ShaHash
	if len(locator) > 0 {
		beginHash = locator[0]
	}

	// Filter duplicate getblocks requests.
	if p.prevGetBlocksStop != nil && p.prevGetBlocksBegin != nil &&
		beginHash != nil && stopHash.IsEqual(p.prevGetBlocksStop) &&
		beginHash.IsEqual(p.prevGetBlocksBegin) {

		log.Tracef("PEER: Filtering duplicate [getblocks] with begin "+
			"hash %v, stop hash %v", beginHash, stopHash)
		return nil
	}

	// Construct the getblocks request and queue it to be sent.
	msg := btcwire.NewMsgGetBlocks(stopHash)
	for _, hash := range locator {
		err := msg.AddBlockLocatorHash(hash)
		if err != nil {
			return err
		}
	}
	p.QueueMessage(msg, nil)

	// Update the previous getblocks request information for filtering
	// duplicates.
	p.prevGetBlocksBegin = beginHash
	p.prevGetBlocksStop = stopHash
	return nil
}

// FetchTxUsedBySha returns the used/spent buffer for a given transaction.
func (db *SqliteDb) FetchTxUsedBySha(txsha *btcwire.ShaHash) (spentbuf []byte, err error) {
	var row *sql.Row
	db.dbLock.Lock()
	defer db.dbLock.Unlock()

	rowBytes := txsha.String()
	txop := db.txop(txFetchUsedByShaStmt)
	row = txop.QueryRow(rowBytes)

	var databytes []byte
	err = row.Scan(&databytes)
	if err == sql.ErrNoRows {
		txop := db.txop(txtmpFetchUsedByShaStmt)
		row = txop.QueryRow(rowBytes)

		err = row.Scan(&databytes)
		if err == sql.ErrNoRows {
			err = btcdb.TxShaMissing
			return
		}
		if err != nil {
			log.Warnf("txtmp FetchLocationBySha: fail %v",
				err)
			return
		}
	}

	if err != nil {
		log.Warnf("FetchUsedBySha: fail %v", err)
		return
	}
	spentbuf = databytes
	return
}

// fetchLocationBySha look up the Tx sha information by name.
// Must be called with db lock held.
func (db *SqliteDb) fetchLocationBySha(txsha *btcwire.ShaHash) (blockidx int64, txoff int, txlen int, err error) {
	var row *sql.Row
	var blockid int64
	var ttxoff int
	var ttxlen int

	rowBytes := txsha.String()
	txop := db.txop(txFetchLocationByShaStmt)
	row = txop.QueryRow(rowBytes)

	err = row.Scan(&blockid, &ttxoff, &ttxlen)
	if err == sql.ErrNoRows {
		txop = db.txop(txtmpFetchLocationByShaStmt)
		row = txop.QueryRow(rowBytes)

		err = row.Scan(&blockid, &ttxoff, &ttxlen)
		if err == sql.ErrNoRows {
			err = btcdb.TxShaMissing
			return
		}
		if err != nil {
			log.Warnf("txtmp FetchLocationBySha: fail %v",
				err)
			return
		}
	}
	if err != nil {
		log.Warnf("FetchLocationBySha: fail %v", err)
		return
	}
	blockidx = blockid - 1
	txoff = ttxoff
	txlen = ttxlen
	return
}

// FetchHeightRange looks up a range of blocks by the start and ending
// heights.  Fetch is inclusive of the start height and exclusive of the
// ending height. To fetch all hashes from the start height until no
// more are present, use the special id `AllShas'.
func (db *LevelDb) FetchHeightRange(startHeight, endHeight int64) (rshalist []btcwire.ShaHash, err error) {
	db.dbLock.Lock()
	defer db.dbLock.Unlock()

	var endidx int64
	if endHeight == btcdb.AllShas {
		endidx = startHeight + 500
	} else {
		endidx = endHeight
	}

	shalist := make([]btcwire.ShaHash, 0, endidx-startHeight)
	for height := startHeight; height < endidx; height++ {
		// TODO(drahn) fix blkFile from height

		key := int64ToKey(height)
		blkVal, lerr := db.lDb.Get(key, db.ro)
		if lerr != nil {
			break
		}

		var sha btcwire.ShaHash
		sha.SetBytes(blkVal[0:32])
		shalist = append(shalist, sha)
	}

	if err != nil {
		return
	}
	//log.Tracef("FetchIdxRange idx %v %v returned %v shas err %v", startHeight, endHeight, len(shalist), err)

	return shalist, nil
}

// RecordMinedTx searches through each account's TxStore, searching for a
// sent transaction with the same txid as from a txmined notification.  If
// the transaction IDs match, the record in the TxStore is updated with
// the full information about the newly-mined tx, and the TxStore is
// scheduled to be written to disk..
func (am *AccountManager) RecordMinedTx(txid *btcwire.ShaHash,
	blkhash *btcwire.ShaHash, blkheight int32, blkindex int,
	blktime int64) error {

	for _, a := range am.AllAccounts() {
		// Search in reverse order.  Since more recently-created
		// transactions are appended to the end of the store, it's
		// more likely to find it when searching from the end.
		for i := len(a.TxStore) - 1; i >= 0; i-- {
			sendtx, ok := a.TxStore[i].(*tx.SendTx)
			if ok {
				if bytes.Equal(txid.Bytes(), sendtx.TxID[:]) {
					copy(sendtx.BlockHash[:], blkhash.Bytes())
					sendtx.BlockHeight = blkheight
					sendtx.BlockIndex = int32(blkindex)
					sendtx.BlockTime = blktime

					am.ds.ScheduleTxStoreWrite(a)

					return nil
				}
			}
		}
	}

	return errors.New("txid does not match any recorded sent transaction")
}

func parsesha(argstr string) (argtype int, height int64, psha *btcwire.ShaHash, err error) {
	var sha btcwire.ShaHash

	var hashbuf string

	switch len(argstr) {
	case 64:
		hashbuf = argstr
	case 66:
		if argstr[0:2] != "0x" {
			log.Infof("prefix is %v", argstr[0:2])
			err = ErrBadShaPrefix
			return
		}
		hashbuf = argstr[2:]
	default:
		if len(argstr) <= 16 {
			// assume value is height
			argtype = ArgHeight
			var h int
			h, err = strconv.Atoi(argstr)
			if err == nil {
				height = int64(h)
				return
			}
			log.Infof("Unable to parse height %v, err %v", height, err)
		}
		err = ErrBadShaLen
		return
	}

	var buf [32]byte
	for idx, ch := range hashbuf {
		var val rune

		switch {
		case ch >= '0' && ch <= '9':
			val = ch - '0'
		case ch >= 'a' && ch <= 'f':
			val = ch - 'a' + rune(10)
		case ch >= 'A' && ch <= 'F':
			val = ch - 'A' + rune(10)
		default:
			err = ErrBadShaChar
			return
		}
		b := buf[31-idx/2]
		if idx&1 == 1 {
			b |= byte(val)
		} else {
			b |= (byte(val) << 4)
		}
		buf[31-idx/2] = b
	}
	sha.SetBytes(buf[0:32])
	psha = &sha
	return
}

// Row returns row data for block iterator.
func (bi *SqliteBlockIterator) Row() (key *btcwire.ShaHash, pver uint32,
	buf []byte, err error) {
	var keybytes []byte

	err = bi.rows.Scan(&keybytes, &pver, &buf)
	if err == nil {
		var retkey btcwire.ShaHash
		retkey.SetBytes(keybytes)
		key = &retkey
	}
	return
}

// ShaHashToBig converts a btcwire.ShaHash into a big.Int that can be used to
// perform math comparisons.
func ShaHashToBig(hash *btcwire.ShaHash) *big.Int {
	// A ShaHash is in little-endian, but the big package wants the bytes
	// in big-endian.  Reverse them.  ShaHash.Bytes makes a copy, so it
	// is safe to modify the returned buffer.
	buf := hash.Bytes()
	blen := len(buf)
	for i := 0; i < blen/2; i++ {
		buf[i], buf[blen-1-i] = buf[blen-1-i], buf[i]
	}

	return new(big.Int).SetBytes(buf)
}

// VerboseGetRawTransaction sends the verbose version of a getrawtransaction
// request to receive details about a transaction.
func VerboseGetRawTransaction(rpc ServerConn, txsha *btcwire.ShaHash) (*btcjson.TxRawResult, *btcjson.Error) {
	// NewGetRawTransactionCmd cannot fail with a single optarg.
	cmd, _ := btcjson.NewGetRawTransactionCmd(<-NewJSONID, txsha.String(), 1)
	response := <-rpc.SendRequest(NewServerRequest(cmd))

	var resultData btcjson.TxRawResult
	_, jsonErr := response.FinishUnmarshal(&resultData)
	if jsonErr != nil {
		return nil, jsonErr
	}
	return &resultData, nil
}

// hashMerkleBranches takes two hashes, treated as the left and right tree
// nodes, and returns the hash of their concatenation.  This is a helper
// function used to during generatation of a merkle tree.
func hashMerkleBranches(left *btcwire.ShaHash, right *btcwire.ShaHash) *btcwire.ShaHash {
	// Concatenate the left and right nodes.
	var sha [btcwire.HashSize * 2]byte
	copy(sha[:btcwire.HashSize], left.Bytes())
	copy(sha[btcwire.HashSize:], right.Bytes())

	// Create a new sha hash from the double sha 256.  Ignore the error
	// here since SetBytes can't fail here due to the fact DoubleSha256
	// always returns a []byte of the right size regardless of input.
	newSha, _ := btcwire.NewShaHash(btcwire.DoubleSha256(sha[:]))
	return newSha
}

func notifySpentData(n ntfnChan, txhash *btcwire.ShaHash, index uint32,
	spender *btcutil.Tx) {

	var buf bytes.Buffer
	// Ignore Serialize's error, as writing to a bytes.buffer
	// cannot fail.
	spender.MsgTx().Serialize(&buf)
	txStr := hex.EncodeToString(buf.Bytes())

	ntfn := btcws.NewTxSpentNtfn(txhash.String(), int(index), txStr)
	n <- ntfn
}

// GetBlockAsync 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 GetBlock for the blocking version and more details.
func (c *Client) GetBlockAsync(blockHash *btcwire.ShaHash) FutureGetBlockResult {
	hash := ""
	if blockHash != nil {
		hash = blockHash.String()
	}

	id := c.NextID()
	cmd, err := btcjson.NewGetBlockCmd(id, hash, false)
	if err != nil {
		return newFutureError(err)
	}

	return c.sendCmd(cmd)
}

// GetBlockVerboseAsync 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 GetBlockVerbose for the blocking version and more details.
func (c *Client) GetBlockVerboseAsync(blockHash *btcwire.ShaHash, verboseTx bool) FutureGetBlockVerboseResult {
	hash := ""
	if blockHash != nil {
		hash = blockHash.String()
	}

	id := c.NextID()
	cmd, err := btcjson.NewGetBlockCmd(id, hash, true, verboseTx)
	if err != nil {
		return newFutureError(err)
	}

	return c.sendCmd(cmd)
}

// fetchBlockShaByHeight returns a block hash based on its height in the
// block chain.
func (db *LevelDb) fetchBlockShaByHeight(height int64) (rsha *btcwire.ShaHash, err error) {
	key := int64ToKey(height)

	blkVal, err := db.lDb.Get(key, db.ro)
	if err != nil {
		log.Tracef("failed to find height %v", height)
		return // exists ???
	}

	var sha btcwire.ShaHash
	sha.SetBytes(blkVal[0:32])

	return &sha, nil
}

func notifySpentData(wallet walletChan, txhash *btcwire.ShaHash, index uint32,
	spender *btcutil.Tx) {

	var buf bytes.Buffer
	// Ignore Serialize's error, as writing to a bytes.buffer
	// cannot fail.
	spender.MsgTx().Serialize(&buf)
	txStr := hex.EncodeToString(buf.Bytes())

	// TODO(jrick): create a new notification in btcws and use that.
	ntfn := btcws.NewTxSpentNtfn(txhash.String(), int(index), txStr)
	mntfn, _ := ntfn.MarshalJSON()
	wallet <- mntfn
}

// GetRawTransactionAsync 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 GetRawTransaction for the blocking version and more details.
func (c *Client) GetRawTransactionAsync(txHash *btcwire.ShaHash) FutureGetRawTransactionResult {
	hash := ""
	if txHash != nil {
		hash = txHash.String()
	}

	id := c.NextID()
	cmd, err := btcjson.NewGetRawTransactionCmd(id, hash, 0)
	if err != nil {
		return newFutureError(err)
	}

	return c.sendCmd(cmd)
}

// insertTx inserts a tx hash and its associated data into the database.
// Must be called with db lock held.
func (db *SqliteDb) insertTx(txsha *btcwire.ShaHash, blockidx int64, txoff int, txlen int, usedbuf []byte) (err error) {

	tx := &db.txState
	if tx.tx == nil {
		err = db.startTx()
		if err != nil {
			return
		}
	}
	blockid := blockidx + 1
	txd := tTxInsertData{txsha: txsha, blockid: blockid, txoff: txoff, txlen: txlen, usedbuf: usedbuf}

	log.Tracef("inserting tx %v for block %v off %v len %v",
		txsha, blockid, txoff, txlen)

	rowBytes := txsha.String()

	var op int // which table to insert data into.
	if db.UseTempTX {
		var tblockid int64
		var ttxoff int
		var ttxlen int
		txop := db.txop(txFetchLocationByShaStmt)
		row := txop.QueryRow(rowBytes)
		err = row.Scan(&tblockid, &ttxoff, &ttxlen)
		if err != sql.ErrNoRows {
			// sha already present
			err = btcdb.DuplicateSha
			return
		}
		op = txtmpInsertStmt
	} else {
		op = txInsertStmt
	}

	txop := db.txop(op)
	_, err = txop.Exec(rowBytes, blockid, txoff, txlen, usedbuf)
	if err != nil {
		log.Warnf("failed to insert %v %v %v", txsha, blockid, err)
		return
	}
	if db.UseTempTX {
		db.TempTblSz++
	}

	// put in insert list for replay
	tx.txInsertList = append(tx.txInsertList, txd)

	return
}

func (db *LevelDb) setBlk(sha *btcwire.ShaHash, blkHeight int64, buf []byte) {
	// serialize
	var lw [8]byte
	binary.LittleEndian.PutUint64(lw[0:8], uint64(blkHeight))

	shaKey := shaBlkToKey(sha)
	blkKey := int64ToKey(blkHeight)

	shaB := sha.Bytes()
	blkVal := make([]byte, len(shaB)+len(buf))
	copy(blkVal[0:], shaB)
	copy(blkVal[len(shaB):], buf)

	db.lBatch().Put(shaKey, lw[:])
	db.lBatch().Put(blkKey, blkVal)
}

// blkExistsSha looks up the given block hash
// returns true if it is present in the database.
// CALLED WITH LOCK HELD
func (db *SqliteDb) blkExistsSha(sha *btcwire.ShaHash) bool {
	var pver uint32

	row := db.blkStmts[blkExistsSha].QueryRow(sha.Bytes())
	err := row.Scan(&pver)

	if err == sql.ErrNoRows {
		return false
	}

	if err != nil {
		// ignore real errors?
		log.Warnf("blkExistsSha: fail %v", err)
		return false
	}
	return true
}

// RescanEndBlockAsync 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 RescanEndBlock for the blocking version and more details.
//
// NOTE: This is a btcd extension and requires a websocket connection.
func (c *Client) RescanEndBlockAsync(startBlock *btcwire.ShaHash,
	addresses []btcutil.Address, outpoints []*btcwire.OutPoint,
	endBlock *btcwire.ShaHash) FutureRescanResult {

	// Not supported in HTTP POST mode.
	if c.config.HttpPostMode {
		return newFutureError(ErrNotificationsNotSupported)
	}

	// Ignore the notification if the client is not interested in
	// notifications.
	if c.ntfnHandlers == nil {
		return newNilFutureResult()
	}

	// Convert block hashes to strings.
	var startBlockShaStr, endBlockShaStr string
	if startBlock != nil {
		startBlockShaStr = startBlock.String()
	}
	if endBlock != nil {
		endBlockShaStr = endBlock.String()
	}

	// Convert addresses to strings.
	addrs := make([]string, 0, len(addresses))
	for _, addr := range addresses {
		addrs = append(addrs, addr.String())
	}

	// Convert outpoints.
	ops := make([]btcws.OutPoint, 0, len(outpoints))
	for _, op := range outpoints {
		ops = append(ops, *btcws.NewOutPointFromWire(op))
	}

	id := c.NextID()
	cmd, err := btcws.NewRescanCmd(id, startBlockShaStr, addrs, ops,
		endBlockShaStr)
	if err != nil {
		return newFutureError(err)
	}

	return c.sendCmd(cmd)
}