Fix example. Update README

README.md

@@ -9,40 +9,22 @@ Contains the zcash signing algorithm and some protocol configuration. Forked fro
 * [Overwinter](https://z.cash/upgrade/overwinter.html) network upgrade for Zcash. Not support joinsplits.
 * [Sapling](https://z.cash/upgrade/sapling/) network upgrade for Zcash.
 
-## Example
-
-```go
-zecTx := &zecutil.MsgTx{
-    MsgTx:        newTx,
-    ExpiryHeight: 215039,
-}
-
-lookupKey := func(a btcutil.Address) (*btcec.PrivateKey, bool, error) {
-    return privKey, wif.CompressPubKey, nil
-}
-sigScript, err := zecutil.SignTxOutput(
-    &params,
-    zecTx,
-    i,
-    prevTxScript,
-    txscript.SigHashAll,
-    txscript.KeyClosure(lookupKey),
-    nil,
-    nil,
-    amount,
-)
-if err != nil {
-    return err
-}
-
-txIn.SignatureScript = sigScript
-
-var buf bytes.Buffer
-if err = zecTx.BtcEncode(&buf, 0, wire.BaseEncoding); err != nil {
-    return err
-}
-
-fmt.Printf("Tx hex: %x\n", buf.Bytes())
-fmt.Printf("Tx Hash: %s\n", zecTx.TxHash().String())
+## How to use
+- First install the dependencies
 
+```bash
+go get github.com/iqoption/zecutil
+go get github.com/btcsuite/btcd
+go get github.com/btcsuite/btcutil
 ```
+
+- Open [example.go](./example.go) and update your wallet details. You can use `http://zcashnetwork.info/api/addr/<your_address>/utxo` to get the list of UTXOs
+
+- Build and run the binary
+
+```bash
+go build example.go
+./example
+```
+
+- You can broadcast your transaction using [this form](http://zcashnetwork.info/tx/send)

example.go

@@ -0,0 +1,132 @@
+package main
+
+import (
+	"bytes"
+	"encoding/hex"
+	"fmt"
+
+	"github.com/btcsuite/btcd/btcec"
+	"github.com/btcsuite/btcd/chaincfg"
+	"github.com/btcsuite/btcd/chaincfg/chainhash"
+	"github.com/btcsuite/btcd/txscript"
+	"github.com/btcsuite/btcd/wire"
+	"github.com/btcsuite/btcutil"
+	"github.com/btcsuite/btcutil/base58"
+	"github.com/iqoption/zecutil"
+)
+
+// Input represents UTXO
+type Input struct {
+	Amount        int64
+	Confirmations uint64
+	Script        string
+	Txid          string
+	Txindex       uint32
+}
+
+// Output represents receiver's address and the amount to be sent
+type Output struct {
+	Address string
+	Amount  int64
+}
+
+func main() {
+	// 5235736f9a7cac938d870f870f3e66c787107b9f4986336d736f0b03c9eb59ae
+
+	netParams := &chaincfg.MainNetParams
+	txVersion := 4
+
+	inputs := []Input{
+		{
+			Amount:        380000,
+			Confirmations: 1,
+			Script:        "76a914b4092afd05b0d3f8cf5836067f8e53d8bc4034c888ac",
+			Txid:          "5606cd664ad26f3643c7041fca5ddac47fffe7e9675e87b8e7d4b84d562ae215",
+			Txindex:       0,
+		},
+		{
+			Amount:        3980000,
+			Confirmations: 13,
+			Script:        "76a914b4092afd05b0d3f8cf5836067f8e53d8bc4034c888ac",
+			Txid:          "ea1d3dc7ac16f93f90e6b8030222471e36f0d0a27e3385ccfbbc6e3513126de6",
+			Txindex:       0,
+		},
+	}
+	outputs := []Output{
+		{
+			Address: "t1TDusBKXRgyruL9wHgQt9vQUW1PwdWAAZo",
+			Amount:  4350000,
+		},
+	}
+	pkey := "L247RjuxKEFpkj3FmfgRGQsioLVkMoVvJk2B7nFhxTyrrm56N2RL"
+
+	var (
+		privateKey *btcutil.WIF
+		err        error
+	)
+
+	if privateKey, err = btcutil.DecodeWIF(pkey); err != nil {
+		panic("can't parse wif")
+	}
+	newTx := wire.NewMsgTx(int32(txVersion))
+
+	for _, receiver := range outputs {
+		decoded := base58.Decode(receiver.Address)
+		var addr *btcutil.AddressPubKeyHash
+		if addr, err = btcutil.NewAddressPubKeyHash(decoded[2:len(decoded)-4], netParams); err != nil {
+			panic(err)
+		}
+
+		receiverPkScript, err := txscript.PayToAddrScript(addr)
+		if err != nil {
+			panic(err)
+		}
+		txOut := wire.NewTxOut(receiver.Amount, receiverPkScript)
+		newTx.AddTxOut(txOut)
+
+	}
+	for _, in := range inputs {
+		var ph *chainhash.Hash
+		if ph, err = chainhash.NewHashFromStr(in.Txid); err != nil {
+			panic(err)
+		}
+		txIn := wire.NewTxIn(wire.NewOutPoint(ph, in.Txindex), nil, nil)
+		newTx.AddTxIn(txIn)
+	}
+
+	zecTx := &zecutil.MsgTx{
+		MsgTx: newTx,
+		// https://github.com/zcash/zcash/blob/0f091f228cdb1793a10ea59f82b7c7f0b93edb7a/src/consensus/consensus.h#L31
+		ExpiryHeight: 500000000 - 1,
+	}
+
+	for idx, in := range inputs {
+		var prevTxScript []byte
+		if prevTxScript, err = hex.DecodeString(in.Script); err != nil {
+			panic(err)
+		}
+		sigScript, err := zecutil.SignTxOutput(
+			netParams,
+			zecTx,
+			idx,
+			prevTxScript,
+			txscript.SigHashAll,
+			txscript.KeyClosure(func(a btcutil.Address) (*btcec.PrivateKey, bool, error) {
+				return privateKey.PrivKey, privateKey.CompressPubKey, nil
+			}),
+			nil,
+			nil,
+			in.Amount)
+		if err != nil {
+			panic(err)
+		}
+		newTx.TxIn[idx].SignatureScript = sigScript
+	}
+
+	var buf bytes.Buffer
+	if err = zecTx.ZecEncode(&buf, 0, wire.BaseEncoding); err != nil {
+		panic(err)
+	}
+	fmt.Printf("Tx raw: %x\n\n", buf.Bytes())
+	fmt.Printf("Tx Hash: %s\n", zecTx.TxHash().String())
+}