// This example demonstrates creating a script which pays to a bitcoin address.
// It also prints the created script hex and uses the DisasmString function to
// display the disassembled script.
func ExamplePayToAddrScript() {
	// Parse the address to send the coins to into a btcutil.Address
	// which is useful to ensure the accuracy of the address and determine
	// the address type.  It is also required for the upcoming call to
	// PayToAddrScript.
	addressStr := "12gpXQVcCL2qhTNQgyLVdCFG2Qs2px98nV"
	address, err := btcutil.DecodeAddress(addressStr, &chaincfg.MainNetParams)
	if err != nil {
		fmt.Println(err)
		return
	}

	// Create a public key script that pays to the address.
	script, err := txscript.PayToAddrScript(address)
	if err != nil {
		fmt.Println(err)
		return
	}
	fmt.Printf("Script Hex: %x\n", script)

	disasm, err := txscript.DisasmString(script)
	if err != nil {
		fmt.Println(err)
		return
	}
	fmt.Println("Script Disassembly:", disasm)

	// Output:
	// Script Hex: 76a914128004ff2fcaf13b2b91eb654b1dc2b674f7ec6188ac
	// Script Disassembly: OP_DUP OP_HASH160 128004ff2fcaf13b2b91eb654b1dc2b674f7ec61 OP_EQUALVERIFY OP_CHECKSIG
}

// createCoinbaseTx returns a coinbase transaction paying an appropriate subsidy
// based on the passed block height to the provided address.  When the address
// is nil, the coinbase transaction will instead be redeemable by anyone.
//
// See the comment for NewBlockTemplate for more information about why the nil
// address handling is useful.
func createCoinbaseTx(params *chaincfg.Params, coinbaseScript []byte, nextBlockHeight int32, addr btcutil.Address) (*btcutil.Tx, error) {
	// Create the script to pay to the provided payment address if one was
	// specified.  Otherwise create a script that allows the coinbase to be
	// redeemable by anyone.
	var pkScript []byte
	if addr != nil {
		var err error
		pkScript, err = txscript.PayToAddrScript(addr)
		if err != nil {
			return nil, err
		}
	} else {
		var err error
		scriptBuilder := txscript.NewScriptBuilder()
		pkScript, err = scriptBuilder.AddOp(txscript.OP_TRUE).Script()
		if err != nil {
			return nil, err
		}
	}

	tx := wire.NewMsgTx(wire.TxVersion)
	tx.AddTxIn(&wire.TxIn{
		// Coinbase transactions have no inputs, so previous outpoint is
		// zero hash and max index.
		PreviousOutPoint: *wire.NewOutPoint(&chainhash.Hash{},
			wire.MaxPrevOutIndex),
		SignatureScript: coinbaseScript,
		Sequence:        wire.MaxTxInSequenceNum,
	})
	tx.AddTxOut(&wire.TxOut{
		Value:    blockchain.CalcBlockSubsidy(nextBlockHeight, params),
		PkScript: pkScript,
	})
	return btcutil.NewTx(tx), nil
}

// TstCreateSeriesCredits creates a new credit for every item in the amounts
// slice, locked to the given series' address with branch==1 and index==0.
func TstCreateSeriesCredits(t *testing.T, pool *Pool, seriesID uint32, amounts []int64) []credit {
	addr := TstNewWithdrawalAddress(t, pool, seriesID, Branch(1), Index(0))
	pkScript, err := txscript.PayToAddrScript(addr.addr)
	if err != nil {
		t.Fatal(err)
	}
	msgTx := createMsgTx(pkScript, amounts)
	txHash := msgTx.TxHash()
	credits := make([]credit, len(amounts))
	for i := range msgTx.TxOut {
		c := wtxmgr.Credit{
			OutPoint: wire.OutPoint{
				Hash:  txHash,
				Index: uint32(i),
			},
			BlockMeta: wtxmgr.BlockMeta{
				Block: wtxmgr.Block{Height: TstInputsBlock},
			},
			Amount:   btcutil.Amount(msgTx.TxOut[i].Value),
			PkScript: msgTx.TxOut[i].PkScript,
		}
		credits[i] = newCredit(c, *addr)
	}
	return credits
}

// makeDestinationScriptSource creates a ChangeSource which is used to receive
// all correlated previous input value.  A non-change address is created by this
// function.
func makeDestinationScriptSource(rpcClient *btcrpcclient.Client, accountName string) txauthor.ChangeSource {
	return func() ([]byte, error) {
		destinationAddress, err := rpcClient.GetNewAddress(accountName)
		if err != nil {
			return nil, err
		}
		return txscript.PayToAddrScript(destinationAddress)
	}
}

// createTxOut generates a TxOut that can be added to a transaction.
func createTxOut(outCoins uint64, addr btcutil.Address) *wire.TxOut {
	// Take the address and generate a PubKeyScript out of it
	script, err := txscript.PayToAddrScript(addr)
	if err != nil {
		log.Fatal(err)
	}
	txout := wire.NewTxOut(int64(outCoins), script)
	return txout
}

// createTxOut generates a TxOut that can be added to a transaction.
func createTxOut(inCoin int64, addr btcutil.Address) *wire.TxOut {
	// Pay the minimum network fee so that nodes will broadcast the tx.
	outCoin := inCoin - TX_FEE
	// Take the address and generate a PubKeyScript out of it
	script, err := txscript.PayToAddrScript(addr)
	if err != nil {
		log.Fatal(err)
	}
	txout := wire.NewTxOut(outCoin, script)
	return txout
}

func TestFakeTxs(t *testing.T) {
	// First we need a wallet.
	w, err := keystore.NewStore("banana wallet", "", []byte("banana"),
		wire.MainNet, &keystore.BlockStamp{}, 100)
	if err != nil {
		t.Errorf("Can not create encrypted wallet: %s", err)
		return
	}
	a := &Wallet{
		Wallet:          w,
		lockedOutpoints: map[wire.OutPoint]struct{}{},
	}

	w.Unlock([]byte("banana"))

	// Create and add a fake Utxo so we have some funds to spend.
	//
	// This will pass validation because txcscript is unaware of invalid
	// tx inputs, however, this example would fail in btcd.
	utxo := &tx.Utxo{}
	addr, err := w.NextChainedAddress(&keystore.BlockStamp{}, 100)
	if err != nil {
		t.Errorf("Cannot get next address: %s", err)
		return
	}
	copy(utxo.AddrHash[:], addr.ScriptAddress())
	ophash := (wire.ShaHash)([...]byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,
		12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27,
		28, 29, 30, 31, 32})
	out := wire.NewOutPoint(&ophash, 0)
	utxo.Out = tx.OutPoint(*out)
	ss, err := txscript.PayToAddrScript(addr)
	if err != nil {
		t.Errorf("Could not create utxo PkScript: %s", err)
		return
	}
	utxo.Subscript = tx.PkScript(ss)
	utxo.Amt = 1000000
	utxo.Height = 12345
	a.UtxoStore = append(a.UtxoStore, utxo)

	// Fake our current block height so btcd doesn't need to be queried.
	curBlock.BlockStamp.Height = 12346

	// Create the transaction.
	pairs := map[string]int64{
		"17XhEvq9Nahdj7Xe1nv6oRe1tEmaHUuynH": 5000,
	}
	_, err = a.txToPairs(pairs, 1)
	if err != nil {
		t.Errorf("Tx creation failed: %s", err)
		return
	}
}

func TstCreatePkScript(t *testing.T, p *Pool, seriesID uint32, branch Branch, idx Index) []byte {
	script := TstEnsureUsedAddr(t, p, seriesID, branch, idx)
	addr, err := p.addressFor(script)
	if err != nil {
		t.Fatal(err)
	}
	pkScript, err := txscript.PayToAddrScript(addr)
	if err != nil {
		t.Fatal(err)
	}
	return pkScript
}

// 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
}

// finalizeCurrentTx finalizes the transaction in w.current, moves it to the
// list of finalized transactions and replaces w.current with a new empty
// transaction.
func (w *withdrawal) finalizeCurrentTx() error {
	log.Debug("Finalizing current transaction")
	tx := w.current
	if len(tx.outputs) == 0 {
		log.Debug("Current transaction has no outputs, doing nothing")
		return nil
	}

	pkScript, err := txscript.PayToAddrScript(w.status.nextChangeAddr.addr)
	if err != nil {
		return newError(ErrWithdrawalProcessing, "failed to generate pkScript for change address", err)
	}
	if tx.addChange(pkScript) {
		var err error
		w.status.nextChangeAddr, err = nextChangeAddress(w.status.nextChangeAddr)
		if err != nil {
			return newError(ErrWithdrawalProcessing, "failed to get next change address", err)
		}
	}

	ntxid := tx.ntxid()
	for i, txOut := range tx.outputs {
		outputStatus := w.status.outputs[txOut.request.outBailmentID()]
		outputStatus.addOutpoint(
			OutBailmentOutpoint{ntxid: ntxid, index: uint32(i), amount: txOut.amount})
	}

	// Check that WithdrawalOutput entries with status==success have the sum of
	// their outpoint amounts matching the requested amount.
	for _, txOut := range tx.outputs {
		// Look up the original request we received because txOut.request may
		// represent a split request and thus have a different amount from the
		// original one.
		outputStatus := w.status.outputs[txOut.request.outBailmentID()]
		origRequest := outputStatus.request
		amtFulfilled := btcutil.Amount(0)
		for _, outpoint := range outputStatus.outpoints {
			amtFulfilled += outpoint.amount
		}
		if outputStatus.status == statusSuccess && amtFulfilled != origRequest.Amount {
			msg := fmt.Sprintf("%s was not completely fulfilled; only %v fulfilled", origRequest,
				amtFulfilled)
			return newError(ErrWithdrawalProcessing, msg, nil)
		}
	}

	w.transactions = append(w.transactions, tx)
	w.current = newWithdrawalTx(w.txOptions)
	return nil
}

func TestSignMultiSigUTXOPkScriptNotP2SH(t *testing.T) {
	tearDown, pool, _ := TstCreatePoolAndTxStore(t)
	defer tearDown()

	mgr := pool.Manager()
	tx := createWithdrawalTx(t, pool, []int64{4e6}, []int64{})
	addr, _ := btcutil.DecodeAddress("1MirQ9bwyQcGVJPwKUgapu5ouK2E2Ey4gX", mgr.ChainParams())
	pubKeyHashPkScript, _ := txscript.PayToAddrScript(addr.(*btcutil.AddressPubKeyHash))
	msgtx := tx.toMsgTx()

	err := signMultiSigUTXO(mgr, msgtx, 0, pubKeyHashPkScript, []RawSig{RawSig{}})

	TstCheckError(t, "", err, ErrTxSigning)
}

func TstNewOutputRequest(t *testing.T, transaction uint32, address string, amount btcutil.Amount,
	net *chaincfg.Params) OutputRequest {
	addr, err := btcutil.DecodeAddress(address, net)
	if err != nil {
		t.Fatalf("Unable to decode address %s", address)
	}
	pkScript, err := txscript.PayToAddrScript(addr)
	if err != nil {
		t.Fatalf("Unable to generate pkScript for %v", addr)
	}
	return OutputRequest{
		PkScript:    pkScript,
		Address:     addr,
		Amount:      amount,
		Server:      "server",
		Transaction: transaction,
	}
}

// createTxOut generates a TxOut that can be added to a transaction.
func createTxOut(inCoin int64, addr btcutil.Address) *wire.TxOut {
	// Pay the minimum network fee so that nodes will broadcast the tx.
	outCoin := *amount
	if outCoin == 0 {
		log.Fatal("You probably don't want to transfer 0 satoshis")
	}
	if outCoin > inCoin-TX_FEE {
		log.Fatal("Can't complete transaction--the request amount" +
			" is larger than available funds after transaction fee")
	}
	// Take the address and generate a PubKeyScript out of it
	script, err := txscript.PayToAddrScript(addr)
	if err != nil {
		log.Fatal(err)
	}
	txout := wire.NewTxOut(outCoin, script)
	return txout
}

func (t *TxStore) SignThis(tx *wire.MsgTx) error {
	fmt.Printf("-= SignThis =-\n")

	// sort tx before signing.
	txsort.InPlaceSort(tx)

	sigs := make([][]byte, len(tx.TxIn))
	// first iterate over each input
	for j, in := range tx.TxIn {
		for k := uint32(0); k < uint32(len(t.Adrs)); k++ {
			child, err := t.rootPrivKey.Child(k + hdkeychain.HardenedKeyStart)
			if err != nil {
				return err
			}
			myadr, err := child.Address(t.Param)
			if err != nil {
				return err
			}
			adrScript, err := txscript.PayToAddrScript(myadr)
			if err != nil {
				return err
			}
			if bytes.Equal(adrScript, in.SignatureScript) {
				fmt.Printf("Hit; key %d matches input %d. Signing.\n", k, j)
				priv, err := child.ECPrivKey()
				if err != nil {
					return err
				}
				sigs[j], err = txscript.SignatureScript(
					tx, j, in.SignatureScript, txscript.SigHashAll, priv, true)
				if err != nil {
					return err
				}
				break
			}
		}
	}
	for i, s := range sigs {
		if s != nil {
			tx.TxIn[i].SignatureScript = s
		}
	}
	return nil
}

// newBobNode generates a test "ln node" to interact with Alice (us). For the
// funding transaction, bob has a single output totaling 7BTC. For our basic
// test, he'll fund the channel with 5BTC, leaving 2BTC to the change output.
// TODO(roasbeef): proper handling of change etc.
func newBobNode() (*bobNode, error) {
	// First, parse Bob's priv key in order to obtain a key he'll use for the
	// multi-sig funding transaction.
	privKey, pubKey := btcec.PrivKeyFromBytes(btcec.S256(), bobsPrivKey)

	// Next, generate an output redeemable by bob.
	bobAddr, err := btcutil.NewAddressPubKey(privKey.PubKey().SerializeCompressed(),
		ActiveNetParams)
	if err != nil {
		return nil, err
	}
	bobAddrScript, err := txscript.PayToAddrScript(bobAddr.AddressPubKeyHash())
	if err != nil {
		return nil, err
	}
	prevOut := wire.NewOutPoint(&wire.ShaHash{}, ^uint32(0))
	// TODO(roasbeef): When the chain rpc is hooked in, assert bob's output
	// actually exists and it unspent in the chain.
	bobTxIn := wire.NewTxIn(prevOut, nil)

	// Using bobs priv key above, create a change address he can spend.
	bobChangeOutput := wire.NewTxOut(2*1e8, bobAddrScript)

	// Bob's initial revocation hash is just his private key with the first
	// byte changed...
	var revocation [20]byte
	copy(revocation[:], bobsPrivKey)
	revocation[0] = 0xff

	// His ID is just as creative...
	var id [wire.HashSize]byte
	id[0] = 0xff

	return &bobNode{
		id:               id,
		privKey:          privKey,
		channelKey:       pubKey,
		deliveryAddress:  bobAddr,
		revocation:       revocation,
		delay:            5,
		availableOutputs: []*wire.TxIn{bobTxIn},
		changeOutputs:    []*wire.TxOut{bobChangeOutput},
	}, nil
}

func TestSignMultiSigUTXORedeemScriptNotFound(t *testing.T) {
	tearDown, pool, _ := TstCreatePoolAndTxStore(t)
	defer tearDown()

	mgr := pool.Manager()
	tx := createWithdrawalTx(t, pool, []int64{4e6}, []int64{})
	// This is a P2SH address for which the addr manager doesn't have the redeem
	// script.
	addr, _ := btcutil.DecodeAddress("3Hb4xcebcKg4DiETJfwjh8sF4uDw9rqtVC", mgr.ChainParams())
	if _, err := mgr.Address(addr); err == nil {
		t.Fatalf("Address %s found in manager when it shouldn't", addr)
	}
	msgtx := tx.toMsgTx()

	pkScript, _ := txscript.PayToAddrScript(addr.(*btcutil.AddressScriptHash))
	err := signMultiSigUTXO(mgr, msgtx, 0, pkScript, []RawSig{RawSig{}})

	TstCheckError(t, "", err, ErrTxSigning)
}

func createTxRemainder(inCoin int64) *wire.TxOut {
	remainder := inCoin - *amount - TX_FEE

	// Put the remainder back in our wallet
	pkBytes, err := hex.DecodeString(*privkey)
	if err != nil {
		log.Fatal(err)
	}
	// Get pubkey object
	_, pubkey := btcec.PrivKeyFromBytes(btcec.S256(), pkBytes)

	// Get an address object from WIF string
	changeAddress := generateAddr(pubkey)

	script, err := txscript.PayToAddrScript(changeAddress)
	if err != nil {
		log.Fatal(err)
	}
	remtx := wire.NewTxOut(remainder, script)
	return remtx
}

// addOutputs adds the given address/amount pairs as outputs to msgtx,
// returning their total amount.
func addOutputs(msgtx *wire.MsgTx, pairs map[string]btcutil.Amount, chainParams *chaincfg.Params) (btcutil.Amount, error) {
	var minAmount btcutil.Amount
	for addrStr, amt := range pairs {
		if amt <= 0 {
			return minAmount, ErrNonPositiveAmount
		}
		minAmount += amt
		addr, err := btcutil.DecodeAddress(addrStr, chainParams)
		if err != nil {
			return minAmount, fmt.Errorf("cannot decode address: %s", err)
		}

		// Add output to spend amt to addr.
		pkScript, err := txscript.PayToAddrScript(addr)
		if err != nil {
			return minAmount, fmt.Errorf("cannot create txout script: %s", err)
		}
		txout := wire.NewTxOut(int64(amt), pkScript)
		msgtx.AddTxOut(txout)
	}
	return minAmount, nil
}

func testMemWalletLockedOutputs(r *Harness, t *testing.T) {
	// Obtain the initial balance of the wallet at this point.
	startingBalance := r.ConfirmedBalance()

	// First, create a signed transaction spending some outputs.
	addr, err := r.NewAddress()
	if err != nil {
		t.Fatalf("unable to generate new address: %v", err)
	}
	pkScript, err := txscript.PayToAddrScript(addr)
	if err != nil {
		t.Fatalf("unable to create script: %v", err)
	}
	outputAmt := btcutil.Amount(50 * btcutil.SatoshiPerBitcoin)
	output := wire.NewTxOut(int64(outputAmt), pkScript)
	tx, err := r.CreateTransaction([]*wire.TxOut{output}, 10)
	if err != nil {
		t.Fatalf("unable to create transaction: %v", err)
	}

	// The current wallet balance should now be at least 50 BTC less
	// (accounting for fees) than the period balance
	currentBalance := r.ConfirmedBalance()
	if !(currentBalance <= startingBalance-outputAmt) {
		t.Fatalf("spent outputs not locked: previous balance %v, "+
			"current balance %v", startingBalance, currentBalance)
	}

	// Now unlocked all the spent inputs within the unbroadcast signed
	// transaction. The current balance should now be exactly that of the
	// starting balance.
	r.UnlockOutputs(tx.TxIn)
	currentBalance = r.ConfirmedBalance()
	if currentBalance != startingBalance {
		t.Fatalf("current and starting balance should now match: "+
			"expected %v, got %v", startingBalance, currentBalance)
	}
}

// createCoinbaseTx returns a coinbase transaction paying an appropriate
// subsidy based on the passed block height to the provided address.
func createCoinbaseTx(coinbaseScript []byte, nextBlockHeight int32,
	addr btcutil.Address, net *chaincfg.Params) (*btcutil.Tx, error) {

	// Create the script to pay to the provided payment address.
	pkScript, err := txscript.PayToAddrScript(addr)
	if err != nil {
		return nil, err
	}

	tx := wire.NewMsgTx()
	tx.AddTxIn(&wire.TxIn{
		// Coinbase transactions have no inputs, so previous outpoint is
		// zero hash and max index.
		PreviousOutPoint: *wire.NewOutPoint(&chainhash.Hash{},
			wire.MaxPrevOutIndex),
		SignatureScript: coinbaseScript,
		Sequence:        wire.MaxTxInSequenceNum,
	})
	tx.AddTxOut(&wire.TxOut{
		Value:    blockchain.CalcBlockSubsidy(nextBlockHeight, net),
		PkScript: pkScript,
	})
	return btcutil.NewTx(tx), nil
}