// Uses the txid of the target funding transaction and asks blockchain.info's
// api for information (in json) relaated to that transaction.
func lookupTxid(hash *wire.ShaHash) *blockChainInfoTx {

	url := "https://blockchain.info/rawtx/" + hash.String()
	resp, err := http.Get(url)
	if err != nil {
		log.Fatal(fmt.Errorf("Tx Lookup failed: %v", err))
	}

	b, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		log.Fatal(fmt.Errorf("TxInfo read failed: %s", err))
	}

	//fmt.Printf("%s\n", b)
	txinfo := &blockChainInfoTx{}
	err = json.Unmarshal(b, txinfo)
	if err != nil {
		log.Fatal(err)
	}

	if txinfo.Ver != 1 {
		log.Fatal(fmt.Errorf("Blockchain.info's response seems bad: %v", txinfo))
	}

	return txinfo
}

// 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 []wire.ShaHash, err error) {
	db.dbLock.Lock()
	defer db.dbLock.Unlock()

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

	shalist := make([]wire.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 wire.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
}

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

// 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 *wire.ShaHash) FutureGetBlockResult {
	hash := ""
	if blockHash != nil {
		hash = blockHash.String()
	}

	cmd := btcjson.NewGetBlockCmd(hash, btcjson.Bool(false), nil)
	return c.sendCmd(cmd)
}

// 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 *wire.ShaHash) FutureGetRawTransactionResult {
	hash := ""
	if txHash != nil {
		hash = txHash.String()
	}

	cmd := btcjson.NewGetRawTransactionCmd(hash, btcjson.Int(0))
	return c.sendCmd(cmd)
}

// GetTxOutAsync 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 GetTxOut for the blocking version and more details.
func (c *Client) GetTxOutAsync(txHash *wire.ShaHash, index uint32, mempool bool) FutureGetTxOutResult {
	hash := ""
	if txHash != nil {
		hash = txHash.String()
	}

	cmd := btcjson.NewGetTxOutCmd(hash, index, &mempool)
	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 *wire.ShaHash, verboseTx bool) FutureGetBlockVerboseResult {
	hash := ""
	if blockHash != nil {
		hash = blockHash.String()
	}

	cmd := btcjson.NewGetBlockCmd(hash, btcjson.Bool(true), &verboseTx)
	return c.sendCmd(cmd)
}

// add txid of interest
func (t *TxStore) AddTxid(txid *wire.ShaHash, height int32) error {
	if txid == nil {
		return fmt.Errorf("tried to add nil txid")
	}
	log.Printf("added %s to OKTxids at height %d\n", txid.String(), height)
	t.OKMutex.Lock()
	t.OKTxids[*txid] = height
	t.OKMutex.Unlock()
	return nil
}

// ShaHashToBig converts a wire.ShaHash into a big.Int that can be used to
// perform math comparisons.
func ShaHashToBig(hash *wire.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)
}

func assertAddrIndexTipIsUpdated(db database.Db, t *testing.T, newestSha *wire.ShaHash, newestBlockIdx int32) {
	// Safe to ignore error, since height will be < 0 in "error" case.
	sha, height, _ := db.FetchAddrIndexTip()
	if newestBlockIdx != height {
		t.Fatalf("Height of address index tip failed to update, "+
			"expected %v, got %v", newestBlockIdx, height)
	}
	if !bytes.Equal(newestSha.Bytes(), sha.Bytes()) {
		t.Fatalf("Sha of address index tip failed to update, "+
			"expected %v, got %v", newestSha, sha)
	}
}

// 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 aid in the generation of a merkle tree.
func HashMerkleBranches(left *wire.ShaHash, right *wire.ShaHash) *wire.ShaHash {
	// Concatenate the left and right nodes.
	var sha [wire.HashSize * 2]byte
	copy(sha[:wire.HashSize], left.Bytes())
	copy(sha[wire.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, _ := wire.NewShaHash(wire.DoubleSha256(sha[:]))
	return newSha
}

// fetchBlockShaByHeight returns a block hash based on its height in the
// block chain.
func (db *LevelDb) fetchBlockShaByHeight(height int64) (rsha *wire.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 wire.ShaHash
	sha.SetBytes(blkVal[0:32])

	return &sha, nil
}

// blockExists determines whether a block with the given hash exists either in
// the main chain or any side chains.
func (b *BlockChain) blockExists(hash *wire.ShaHash) (bool, error) {
	// Check memory chain first (could be main chain or side chain blocks).
	if _, ok := b.index[*hash]; ok {
		return true, nil
	}

	// Check if it's the latest checkpoint block
	if hash.IsEqual(b.chainParams.Checkpoints[len(b.chainParams.Checkpoints)-1].Hash) {
		return true, nil
	}

	// Check in database (rest of main chain not in memory).
	return b.db.ExistsSha(hash)
}

func (db *LevelDb) setBlk(sha *wire.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)
}

// fetchAddrIndexTip returns the last block height and block sha to be indexed.
// Meta-data about the address tip is currently cached in memory, and will be
// updated accordingly by functions that modify the state. This function is
// used on start up to load the info into memory. Callers will use the public
// version of this function below, which returns our cached copy.
func (db *LevelDb) fetchAddrIndexTip() (*wire.ShaHash, int64, error) {
	db.dbLock.Lock()
	defer db.dbLock.Unlock()

	data, err := db.lDb.Get(addrIndexMetaDataKey, db.ro)
	if err != nil {
		return &wire.ShaHash{}, -1, database.ErrAddrIndexDoesNotExist
	}

	var blkSha wire.ShaHash
	blkSha.SetBytes(data[0:32])

	blkHeight := binary.LittleEndian.Uint64(data[32:])

	return &blkSha, int64(blkHeight), nil
}

// newDummyCredit creates a new credit with the given hash and outpointIdx,
// locked to the votingpool address identified by the given
// series/index/branch.
func newDummyCredit(t *testing.T, pool *Pool, series uint32, index Index, branch Branch,
	txSha []byte, outpointIdx uint32) credit {
	var hash wire.ShaHash
	if err := hash.SetBytes(txSha); err != nil {
		t.Fatal(err)
	}
	// Ensure the address defined by the given series/branch/index is present on
	// the set of used addresses as that's a requirement of WithdrawalAddress.
	TstEnsureUsedAddr(t, pool, series, branch, index)
	addr := TstNewWithdrawalAddress(t, pool, series, branch, index)
	c := wtxmgr.Credit{
		OutPoint: wire.OutPoint{
			Hash:  hash,
			Index: outpointIdx,
		},
	}
	return newCredit(c, *addr)
}

// GetTx takes a txid and returns the transaction.  If we have it.
func (ts *TxStore) GetTx(txid *wire.ShaHash) (*wire.MsgTx, error) {
	rtx := wire.NewMsgTx()

	err := ts.StateDB.View(func(btx *bolt.Tx) error {
		txns := btx.Bucket(BKTTxns)
		if txns == nil {
			return fmt.Errorf("no transactions in db")
		}
		txbytes := txns.Get(txid.Bytes())
		if txbytes == nil {
			return fmt.Errorf("tx %x not in db", txid.String())
		}
		buf := bytes.NewBuffer(txbytes)
		return rtx.Deserialize(buf)
	})
	if err != nil {
		return nil, err
	}
	return rtx, nil
}

func (db *LevelDb) getBlkByHeight(blkHeight int64) (rsha *wire.ShaHash, rbuf []byte, err error) {
	var blkVal []byte

	key := int64ToKey(blkHeight)

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

	var sha wire.ShaHash

	sha.SetBytes(blkVal[0:32])

	blockdata := make([]byte, len(blkVal[32:]))
	copy(blockdata[:], blkVal[32:])

	return &sha, blockdata, nil
}

// 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 *wire.ShaHash,
	addresses []btcutil.Address, outpoints []*wire.OutPoint,
	endBlock *wire.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([]btcjson.OutPoint, 0, len(outpoints))
	for _, op := range outpoints {
		ops = append(ops, newOutPointFromWire(op))
	}

	cmd := btcjson.NewRescanCmd(startBlockShaStr, addrs, ops,
		&endBlockShaStr)
	return c.sendCmd(cmd)
}

func (db *LevelDb) getBlkLoc(sha *wire.ShaHash) (int32, error) {
	key := shaBlkToKey(sha)

	checkpointSha, _ := wire.NewShaHashFromStr("00000000000000000a8dc6ed5b133d0eb2fd6af56203e4159789b092defd8ab2")
	if sha.IsEqual(checkpointSha) {
		return 382320, nil
	}

	data, err := db.lDb.Get(key, db.ro)
	if err != nil {

		if err == leveldb.ErrNotFound {
			err = database.ErrBlockShaMissing
		}
		return 0, err
	}

	// deserialize
	blkHeight := binary.LittleEndian.Uint64(data)

	return int32(blkHeight), nil
}