// Make sure to call with the mutex locked
func (db *BlockDB) addToCache(h *btc.Uint256, bl []byte, str *btc.Block) (crec *BlckCachRec) {
	if db.cache == nil {
		return
	}
	crec = db.cache[h.BIdx()]
	if crec != nil {
		crec.Data = bl
		if str != nil {
			crec.Block = str
		}
		crec.LastUsed = time.Now()
		return
	}
	if len(db.cache) >= db.max_cached_blocks {
		var oldest_t time.Time
		var oldest_k [btc.Uint256IdxLen]byte
		for k, v := range db.cache {
			if oldest_t.IsZero() || v.LastUsed.Before(oldest_t) {
				oldest_t = v.LastUsed
				oldest_k = k
			}
		}
		delete(db.cache, oldest_k)
	}
	crec = &BlckCachRec{LastUsed: time.Now(), Data: bl, Block: str}
	db.cache[h.BIdx()] = crec
	return
}

// Download raw transaction from blockr.io
func GetTxFromBlockrIo(txid *btc.Uint256) (raw []byte) {
	url := "http://btc.blockr.io/api/v1/tx/raw/" + txid.String()
	r, er := http.Get(url)
	if er == nil {
		if r.StatusCode == 200 {
			defer r.Body.Close()
			c, _ := ioutil.ReadAll(r.Body)
			var txx struct {
				Status string
				Data   struct {
					Tx struct {
						Hex string
					}
				}
			}
			er = json.Unmarshal(c[:], &txx)
			if er == nil {
				raw, _ = hex.DecodeString(txx.Data.Tx.Hex)
			}
		} else {
			fmt.Println("btc.blockr.io StatusCode=", r.StatusCode)
		}
	}
	if er != nil {
		fmt.Println("btc.blockr.io:", er.Error())
	}
	return
}

func (c *OneConnection) SendCmpctBlk(hash *btc.Uint256) {
	crec := GetchBlockForBIP152(hash)
	if crec == nil {
		fmt.Println(c.ConnID, "cmpctblock not sent for", hash.String())
		return
	}

	k0 := binary.LittleEndian.Uint64(crec.BIP152[8:16])
	k1 := binary.LittleEndian.Uint64(crec.BIP152[16:24])

	msg := new(bytes.Buffer)
	msg.Write(crec.Data[:80])
	msg.Write(crec.BIP152[:8])
	btc.WriteVlen(msg, uint64(len(crec.Block.Txs)-1)) // all except coinbase
	for i := 1; i < len(crec.Block.Txs); i++ {
		var lsb [8]byte
		var hasz *btc.Uint256
		if c.Node.SendCmpctVer == 2 {
			hasz = crec.Block.Txs[i].WTxID()
		} else {
			hasz = crec.Block.Txs[i].Hash
		}
		binary.LittleEndian.PutUint64(lsb[:], siphash.Hash(k0, k1, hasz.Hash[:]))
		msg.Write(lsb[:6])
	}
	msg.Write([]byte{1}) // one preffiled tx
	msg.Write([]byte{0}) // coinbase - index 0
	if c.Node.SendCmpctVer == 2 {
		msg.Write(crec.Block.Txs[0].Raw) // coinbase - index 0
	} else {
		crec.Block.Txs[0].WriteSerialized(msg) // coinbase - index 0
	}
	c.SendRawMsg("cmpctblock", msg.Bytes())
}

// Adds a transaction to the rejected list or not, it it has been mined already
// Make sure to call it with locked TxMutex.
// Returns the OneTxRejected or nil if it has not been added.
func RejectTx(id *btc.Uint256, size int, why byte) *OneTxRejected {
	rec := new(OneTxRejected)
	rec.Id = id
	rec.Time = time.Now()
	rec.Size = uint32(size)
	rec.Reason = why
	TransactionsRejected[id.BIdx()] = rec
	return rec
}

// Download raw transaction from webbtc.com
func GetTxFromWebBTC(txid *btc.Uint256) (raw []byte) {
	url := "http://webbtc.com/tx/" + txid.String() + ".bin"
	r, er := http.Get(url)
	if er == nil && r.StatusCode == 200 {
		raw, _ = ioutil.ReadAll(r.Body)
		r.Body.Close()
	}
	return
}

func txChecker(h *btc.Uint256) bool {
	TxMutex.Lock()
	rec, ok := TransactionsToSend[h.BIdx()]
	TxMutex.Unlock()
	if ok && rec.Own != 0 {
		return false // Assume own txs as non-trusted
	}
	if ok {
		common.CountSafe("TxScrBoosted")
	} else {
		common.CountSafe("TxScrMissed")
	}
	return ok
}

// Download raw transaction from a web server (try one after another)
func GetTxFromWeb(txid *btc.Uint256) (raw []byte) {
	raw = GetTxFromExplorer(txid)
	if raw != nil && txid.Equal(btc.NewSha2Hash(raw)) {
		println("GetTxFromExplorer - OK")
		return
	}

	raw = GetTxFromWebBTC(txid)
	if raw != nil && txid.Equal(btc.NewSha2Hash(raw)) {
		println("GetTxFromWebBTC - OK")
		return
	}

	raw = GetTxFromBlockrIo(txid)
	if raw != nil && txid.Equal(btc.NewSha2Hash(raw)) {
		println("GetTxFromBlockrIo - OK")
		return
	}

	raw = GetTxFromBlockchainInfo(txid)
	if raw != nil && txid.Equal(btc.NewSha2Hash(raw)) {
		println("GetTxFromBlockchainInfo - OK")
		return
	}

	return
}

func (db *BlockDB) BlockGetExt(hash *btc.Uint256) (cacherec *BlckCachRec, trusted bool, e error) {
	db.mutex.Lock()
	rec, ok := db.blockIndex[hash.BIdx()]
	if !ok {
		db.mutex.Unlock()
		e = errors.New("btc.Block not in the index")
		return
	}

	trusted = rec.trusted
	if db.cache != nil {
		if crec, hit := db.cache[hash.BIdx()]; hit {
			cacherec = crec
			crec.LastUsed = time.Now()
			db.mutex.Unlock()
			return
		}
	}
	db.mutex.Unlock()

	bl := make([]byte, rec.blen)

	// we will re-open the data file, to not spoil the writting pointer
	f, e := os.Open(db.dirname + "blockchain.dat")
	if e != nil {
		return
	}

	_, e = f.Seek(int64(rec.fpos), os.SEEK_SET)
	if e == nil {
		_, e = f.Read(bl[:])
	}
	f.Close()

	if rec.compressed {
		if rec.snappied {
			bl, _ = snappy.Decode(nil, bl)
		} else {
			gz, _ := gzip.NewReader(bytes.NewReader(bl))
			bl, _ = ioutil.ReadAll(gz)
			gz.Close()
		}
	}

	db.mutex.Lock()
	cacherec = db.addToCache(hash, bl, nil)
	db.mutex.Unlock()

	return
}

// This function is called from the main thread (or from an UI)
func NetRouteInvExt(typ uint32, h *btc.Uint256, fromConn *OneConnection, fee_spkb uint64) (cnt uint) {
	common.CountSafe(fmt.Sprint("NetRouteInv", typ))

	// Prepare the inv
	inv := new([36]byte)
	binary.LittleEndian.PutUint32(inv[0:4], typ)
	copy(inv[4:36], h.Bytes())

	// Append it to PendingInvs in each open connection
	Mutex_net.Lock()
	for _, v := range OpenCons {
		if v != fromConn { // except the one that this inv came from
			send_inv := true
			v.Mutex.Lock()
			if typ == MSG_TX {
				if v.Node.DoNotRelayTxs {
					send_inv = false
					common.CountSafe("SendInvNoTxNode")
				} else if v.X.MinFeeSPKB > 0 && uint64(v.X.MinFeeSPKB) > fee_spkb {
					send_inv = false
					common.CountSafe("SendInvFeeTooLow")
				}

				/* This is to prevent sending own txs to "spying" peers:
				else if fromConn==nil && v.X.InvsRecieved==0 {
					send_inv = false
					common.CountSafe("SendInvOwnBlocked")
				}
				*/
			}
			if send_inv {
				if len(v.PendingInvs) < 500 {
					if typ, ok := v.InvDone.Map[hash2invid(inv[4:36])]; ok {
						common.CountSafe(fmt.Sprint("SendInvSame-", typ))
					} else {
						v.PendingInvs = append(v.PendingInvs, inv)
						cnt++
					}
				} else {
					common.CountSafe("SendInvFull")
				}
			}
			v.Mutex.Unlock()
		}
	}
	Mutex_net.Unlock()
	return
}

// Download raw transaction from webbtc.com
func GetTxFromWebBTC(txid *btc.Uint256) (raw []byte) {
	url := "https://webbtc.com/tx/" + txid.String() + ".bin"
	r, er := http.Get(url)
	if er == nil {
		if r.StatusCode == 200 {
			raw, _ = ioutil.ReadAll(r.Body)
			r.Body.Close()
		} else {
			fmt.Println("webbtc.com StatusCode=", r.StatusCode)
		}
	}
	if er != nil {
		fmt.Println("webbtc.com:", er.Error())
	}
	return
}

// Download (and re-assemble) raw transaction from blockexplorer.com
func GetTxFromBlockchainInfo(txid *btc.Uint256) (rawtx []byte) {
	url := "https://blockchain.info/tx/" + txid.String() + "?format=hex"
	r, er := http.Get(url)
	if er == nil {
		if r.StatusCode == 200 {
			defer r.Body.Close()
			rawhex, _ := ioutil.ReadAll(r.Body)
			rawtx, er = hex.DecodeString(string(rawhex))
		} else {
			fmt.Println("blockchain.info StatusCode=", r.StatusCode)
		}
	}
	if er != nil {
		fmt.Println("blockexplorer.com:", er.Error())
	}
	return
}

func (db *BlockDB) addToCache(h *btc.Uint256, bl []byte) {
	if rec, ok := db.cache[h.BIdx()]; ok {
		rec.used = time.Now()
		return
	}
	if uint(len(db.cache)) >= MaxCachedBlocks {
		var oldest_t time.Time
		var oldest_k [btc.Uint256IdxLen]byte
		for k, v := range db.cache {
			if oldest_t.IsZero() || v.used.Before(oldest_t) {
				oldest_t = v.used
				oldest_k = k
			}
		}
		delete(db.cache, oldest_k)
	}
	db.cache[h.BIdx()] = &cacheRecord{used: time.Now(), data: bl}
}

// Get tx with given id from the balance folder, of from cache
func tx_from_balance(txid *btc.Uint256, error_is_fatal bool) (tx *btc.Tx) {
	if tx = loadedTxs[txid.Hash]; tx != nil {
		return // we have it in cache already
	}
	fn := "balance/" + txid.String() + ".tx"
	buf, er := ioutil.ReadFile(fn)
	if er == nil && buf != nil {
		var th [32]byte
		btc.ShaHash(buf, th[:])
		if txid.Hash == th {
			tx, _ = btc.NewTx(buf)
			if error_is_fatal && tx == nil {
				println("Transaction is corrupt:", txid.String())
				cleanExit(1)
			}
		} else if error_is_fatal {
			println("Transaction file is corrupt:", txid.String())
			cleanExit(1)
		}
	} else if error_is_fatal {
		println("Error reading transaction file:", fn)
		if er != nil {
			println(er.Error())
		}
		cleanExit(1)
	}
	loadedTxs[txid.Hash] = tx // store it in the cache
	return
}

func GetchBlockForBIP152(hash *btc.Uint256) (crec *chain.BlckCachRec) {
	crec, _, _ = common.BlockChain.Blocks.BlockGetExt(hash)

	if crec == nil {
		fmt.Println("BlockGetExt failed for", hash.String())
		return
	}

	if crec.Block == nil {
		crec.Block, _ = btc.NewBlock(crec.Data)
		if crec.Block == nil {
			fmt.Println("SendCmpctBlk: btc.NewBlock() failed for", hash.String())
			return
		}
	}

	if len(crec.Block.Txs) == 0 {
		if crec.Block.BuildTxList() != nil {
			fmt.Println("SendCmpctBlk: bl.BuildTxList() failed for", hash.String())
			return
		}
	}

	if len(crec.BIP152) != 24 {
		crec.BIP152 = make([]byte, 24)
		copy(crec.BIP152[:8], crec.Data[48:56]) // set the nonce to 8 middle-bytes of block's merkle_root
		sha := sha256.New()
		sha.Write(crec.Data[:80])
		sha.Write(crec.BIP152[:8])
		copy(crec.BIP152[8:24], sha.Sum(nil)[0:16])
	}

	return
}

// Download (and re-assemble) raw transaction from blockexplorer.com
func GetTxFromExplorer(txid *btc.Uint256) (rawtx []byte) {
	url := "http://blockexplorer.com/api/rawtx/" + txid.String()
	r, er := http.Get(url)
	if er == nil {
		if r.StatusCode == 200 {
			defer r.Body.Close()
			c, _ := ioutil.ReadAll(r.Body)
			var txx struct {
				Raw string `json:"rawtx"`
			}
			er = json.Unmarshal(c[:], &txx)
			if er == nil {
				rawtx, er = hex.DecodeString(txx.Raw)
			}
		} else {
			fmt.Println("blockexplorer.com StatusCode=", r.StatusCode)
		}
	}
	if er != nil {
		fmt.Println("blockexplorer.com:", er.Error())
	}
	return
}

func SendInvToRandomPeer(typ uint32, h *btc.Uint256) {
	common.CountSafe(fmt.Sprint("NetSendOneInv", typ))

	// Prepare the inv
	inv := new([36]byte)
	binary.LittleEndian.PutUint32(inv[0:4], typ)
	copy(inv[4:36], h.Bytes())

	// Append it to PendingInvs in a random connection
	network.Mutex_net.Lock()
	idx := rand.Intn(len(network.OpenCons))
	var cnt int
	for _, v := range network.OpenCons {
		if idx == cnt {
			v.Mutex.Lock()
			v.PendingInvs = append(v.PendingInvs, inv)
			v.Mutex.Unlock()
			break
		}
		cnt++
	}
	network.Mutex_net.Unlock()
	return
}

// This function is called from the main thread (or from an UI)
func NetRouteInv(typ uint32, h *btc.Uint256, fromConn *OneConnection) (cnt uint) {
	common.CountSafe(fmt.Sprint("NetRouteInv", typ))

	// Prepare the inv
	inv := new([36]byte)
	binary.LittleEndian.PutUint32(inv[0:4], typ)
	copy(inv[4:36], h.Bytes())

	// Append it to PendingInvs in each open connection
	Mutex_net.Lock()
	for _, v := range OpenCons {
		if v != fromConn { // except the one that this inv came from
			v.Mutex.Lock()
			if v.Node.DoNotRelayTxs && typ == 1 {
				// This node does not want tx inv (it came with its version message)
				common.CountSafe("SendInvNoTxNode")
			} else {
				if fromConn == nil && v.InvsRecieved == 0 {
					// Do not broadcast own txs to nodes that never sent any invs to us
					common.CountSafe("SendInvOwnBlocked")
				} else if len(v.PendingInvs) < 500 {
					v.PendingInvs = append(v.PendingInvs, inv)
					cnt++
				} else {
					common.CountSafe("SendInvIgnored")
				}
			}
			v.Mutex.Unlock()
		}
	}
	Mutex_net.Unlock()
	if cnt == 0 {
		NetAlerts <- "WARNING: your tx has not been broadcasted to any peer"
	}
	return
}

// Return false if we do not want to receive a data for this tx
func NeedThisTx(id *btc.Uint256, cb func()) (res bool) {
	TxMutex.Lock()
	if _, present := TransactionsToSend[id.BIdx()]; present {
		//res = false
	} else if _, present := TransactionsRejected[id.BIdx()]; present {
		//res = false
	} else if _, present := TransactionsPending[id.BIdx()]; present {
		//res = false
	} else if txo, _ := common.BlockChain.Unspent.UnspentGet(&btc.TxPrevOut{Hash: id.Hash}); txo != nil {
		// This assumes that tx's out #0 has not been spent yet, which may not always be the case, but well...
		common.CountSafe("TxMinedRejected")
	} else {
		res = true
		if cb != nil {
			cb()
		}
	}
	TxMutex.Unlock()
	return
}

func main() {
	if len(os.Args) < 2 {
		fmt.Println("Specify a path to folder containig blockchain.dat and blockchain.new")
		fmt.Println("Output bootstrap.dat file will be written in the current folder.")
		return
	}

	blks := chain.NewBlockDB(os.Args[1])
	if blks == nil {
		return
	}
	fmt.Println("Loading block index...")
	bidx = make(map[[32]byte]*chain.BlockTreeNode, 300e3)
	blks.LoadBlockIndex(nil, walk)

	var tail, nd *chain.BlockTreeNode
	var genesis_block_hash *btc.Uint256
	for _, v := range bidx {
		if v == tail {
			// skip root block (should be only one)
			continue
		}

		par_hash := btc.NewUint256(v.BlockHeader[4:36])
		par, ok := bidx[par_hash.Hash]
		if !ok {
			genesis_block_hash = par_hash
		} else {
			v.Parent = par
			if tail == nil || v.Height > tail.Height {
				tail = v
			}
		}
	}

	if genesis_block_hash == nil {
		println("genesis_block_hash not found")
		return
	}

	var magic []byte

	gen_bin, _ := hex.DecodeString(GenesisBitcoin)
	tmp := btc.NewSha2Hash(gen_bin[:80])
	if genesis_block_hash.Equal(tmp) {
		println("Bitcoin genesis block")
		magic = []byte{0xF9, 0xBE, 0xB4, 0xD9}
	}

	if magic == nil {
		gen_bin, _ := hex.DecodeString(GenesisTestnet)
		tmp = btc.NewSha2Hash(gen_bin[:80])
		if genesis_block_hash.Equal(tmp) {
			println("Testnet3 genesis block")
			magic = []byte{0x0B, 0x11, 0x09, 0x07}
		}
	}

	if magic == nil {
		println("Unknow genesis block", genesis_block_hash.String())
		println("Aborting since cannot figure out the magic bytes")
		return
	}

	var total_data, curr_data int64

	for nd = tail; nd.Parent != nil; {
		nd.Parent.Childs = []*chain.BlockTreeNode{nd}
		total_data += int64(nd.BlockSize)
		nd = nd.Parent
	}
	fmt.Println("Writting bootstrap.dat, height", tail.Height, "  magic", hex.EncodeToString(magic))
	f, _ := os.Create("bootstrap.dat")
	f.Write(magic)
	binary.Write(f, binary.LittleEndian, uint32(len(gen_bin)))
	f.Write(gen_bin)
	for {
		bl, _, _ := blks.BlockGet(nd.BlockHash)
		f.Write(magic)
		binary.Write(f, binary.LittleEndian, uint32(len(bl)))
		f.Write(bl)
		curr_data += int64(nd.BlockSize)
		if (nd.Height & 0xfff) == 0 {
			fmt.Printf("\r%.1f%%...", 100*float64(curr_data)/float64(total_data))
		}
		if len(nd.Childs) == 0 {
			break
		}
		nd = nd.Childs[0]
	}
	fmt.Println("\rDone           ")
}

// Download (and re-assemble) raw transaction from blockexplorer.com
func GetTxFromExplorer(txid *btc.Uint256) ([]byte, []byte) {
	url := "http://blockexplorer.com/rawtx/" + txid.String()
	r, er := http.Get(url)
	if er == nil && r.StatusCode == 200 {
		defer r.Body.Close()
		c, _ := ioutil.ReadAll(r.Body)
		var txx onetx
		er = json.Unmarshal(c[:], &txx)
		if er == nil {
			// This part looks weird, but this is how I solved seq=FFFFFFFF, if the field not present:
			for i := range txx.In {
				txx.In[i].Sequence = 0xffffffff
			}
			json.Unmarshal(c[:], &txx)
			// ... end of the weird solution

			tx := new(btc.Tx)
			tx.Version = txx.Ver
			tx.TxIn = make([]*btc.TxIn, len(txx.In))
			for i := range txx.In {
				tx.TxIn[i] = new(btc.TxIn)
				tx.TxIn[i].Input.Hash = btc.NewUint256FromString(txx.In[i].Prev_out.Hash).Hash
				tx.TxIn[i].Input.Vout = txx.In[i].Prev_out.N
				if txx.In[i].Prev_out.N == 0xffffffff &&
					txx.In[i].Prev_out.Hash == "0000000000000000000000000000000000000000000000000000000000000000" {
					tx.TxIn[i].ScriptSig, _ = hex.DecodeString(txx.In[i].Coinbase)
				} else {
					tx.TxIn[i].ScriptSig, _ = btc.DecodeScript(txx.In[i].ScriptSig)
				}
				tx.TxIn[i].Sequence = txx.In[i].Sequence
			}
			tx.TxOut = make([]*btc.TxOut, len(txx.Out))
			for i := range txx.Out {
				am, er := btc.StringToSatoshis(txx.Out[i].Value)
				if er != nil {
					fmt.Println("Incorrect BTC amount", txx.Out[i].Value, er.Error())
					return nil, nil
				}
				tx.TxOut[i] = new(btc.TxOut)
				tx.TxOut[i].Value = am
				tx.TxOut[i].Pk_script, _ = btc.DecodeScript(txx.Out[i].ScriptPubKey)
			}
			tx.Lock_time = txx.Lock_time
			rawtx := tx.Serialize()
			if txx.Size != uint(len(rawtx)) {
				fmt.Printf("Transaction size mismatch: %d expexted, %d decoded\n", txx.Size, len(rawtx))
				return nil, rawtx
			}
			curid := btc.NewSha2Hash(rawtx)
			if !curid.Equal(txid) {
				fmt.Println("The downloaded transaction does not match its ID.", txid.String())
				return nil, rawtx
			}
			return rawtx, rawtx
		} else {
			fmt.Println("json.Unmarshal:", er.Error())
		}
	} else {
		if er != nil {
			fmt.Println("http.Get:", er.Error())
		} else {
			fmt.Println("StatusCode=", r.StatusCode)
		}
	}
	return nil, nil
}