package wallet

import (
	"fmt"
	"io/ioutil"
	"os"
	"testing"
	"time"

	"github.com/btcsuite/btcd/btcec"
	"github.com/btcsuite/btcd/txscript"
	"github.com/btcsuite/btcd/wire"
	"github.com/btcsuite/btcutil"
	"github.com/btcsuite/btcwallet/waddrmgr"
	"github.com/btcsuite/btcwallet/wtxmgr"
)

var (
	privPass = []byte("private-test")

	// For simplicity a single priv key controls all of our test outputs.
	testWalletPrivKey = []byte{
		0x2b, 0xd8, 0x06, 0xc9, 0x7f, 0x0e, 0x00, 0xaf,
		0x1a, 0x1f, 0xc3, 0x32, 0x8f, 0xa7, 0x63, 0xa9,
		0x26, 0x97, 0x23, 0xc8, 0xdb, 0x8f, 0xac, 0x4f,
		0x93, 0xaf, 0x71, 0xdb, 0x18, 0x6d, 0x6e, 0x90,
	}

	// We're alice :)
	bobsPrivKey = []byte{
		0x81, 0xb6, 0x37, 0xd8, 0xfc, 0xd2, 0xc6, 0xda,
		0x63, 0x59, 0xe6, 0x96, 0x31, 0x13, 0xa1, 0x17,
		0xd, 0xe7, 0x95, 0xe4, 0xb7, 0x25, 0xb8, 0x4d,
		0x1e, 0xb, 0x4c, 0xfd, 0x9e, 0xc5, 0x8c, 0xe9,
	}

	// Use a hard-coded HD seed in order to avoid derivation.
	testHdSeed = []byte{
		0xb7, 0x94, 0x38, 0x5f, 0x2d, 0x1e, 0xf7, 0xab,
		0x4d, 0x92, 0x73, 0xd1, 0x90, 0x63, 0x81, 0xb4,
		0x4f, 0x2f, 0x6f, 0x25, 0x88, 0xa3, 0xef, 0xb9,
		0x6a, 0x49, 0x18, 0x83, 0x31, 0x98, 0x47, 0x53,
	}
)

// bobNode represents the other party involved as a node within LN. Bob is our
// only "default-route", we have a direct connection with him.
type bobNode struct {
	privKey     *btcec.PrivateKey
	multiSigKey *btcec.PublicKey

	availableOutputs []*wire.TxIn
	changeOutputs    []*wire.TxOut
}

// signFundingTx generates signatures for all the inputs in the funding tx
// belonging to Bob.
func (b *bobNode) signFundingTx(fundingTx *wire.MsgTx) ([][]byte, error) {
	bobSigs := make([][]byte, 0, len(b.availableOutputs))
	bobPkScript := b.changeOutputs[0].PkScript
	for i, _ := range fundingTx.TxIn {
		// Alice has already signed this input
		if fundingTx.TxIn[i].SignatureScript != nil {
			continue
		}

		sigScript, err := txscript.SignatureScript(fundingTx, i,
			bobPkScript, txscript.SigHashAll, b.privKey,
			true)
		if err != nil {
			return nil, err
		}
		bobSigs[i] = sigScript

	}

	return bobSigs, 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, bobAddrScript)

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

	return &bobNode{
		privKey:          privKey,
		multiSigKey:      pubKey,
		availableOutputs: []*wire.TxIn{bobTxIn},
		changeOutputs:    []*wire.TxOut{bobChangeOutput},
	}, nil
}

// addTestTx adds a output spendable by our test wallet, marked as included in
// 'block'.
func addTestTx(w *LightningWallet, rec *wtxmgr.TxRecord, block *wtxmgr.BlockMeta) error {
	err := w.wallet.TxStore.InsertTx(rec, block)
	if err != nil {
		return err
	}

	// Check every output to determine whether it is controlled by a wallet
	// key.  If so, mark the output as a credit.
	for i, output := range rec.MsgTx.TxOut {
		_, addrs, _, err := txscript.ExtractPkScriptAddrs(output.PkScript,
			ActiveNetParams)
		if err != nil {
			// Non-standard outputs are skipped.
			continue
		}
		for _, addr := range addrs {
			ma, err := w.wallet.Manager.Address(addr)
			if err == nil {
				err = w.wallet.TxStore.AddCredit(rec, block, uint32(i),
					ma.Internal())
				if err != nil {
					return err
				}
				err = w.wallet.Manager.MarkUsed(addr)
				if err != nil {
					return err
				}
				continue
			}

			// Missing addresses are skipped.  Other errors should
			// be propagated.
			if !waddrmgr.IsError(err, waddrmgr.ErrAddressNotFound) {
				return err
			}
		}
	}
	return nil
}

func loadTestCredits(w *LightningWallet, numOutputs, btcPerOutput int) error {
	// Import the priv key (converting to WIF) above that controls all our
	// available outputs.
	privKey, _ := btcec.PrivKeyFromBytes(btcec.S256(), testWalletPrivKey)
	fmt.Println("unlocking wallet")
	if err := w.wallet.Unlock(privPass, time.Duration(0)); err != nil {
		return err
	}
	fmt.Println("wallet unlocked")
	bs := &waddrmgr.BlockStamp{Height: 2}
	wif, err := btcutil.NewWIF(privKey, ActiveNetParams, true)
	if err != nil {
		return err
	}
	fmt.Println("importing priv key")
	if _, err := w.wallet.ImportPrivateKey(wif, bs, false); err != nil {
		return nil
	}
	fmt.Println("priv key imported")

	blk := wtxmgr.BlockMeta{wtxmgr.Block{wire.ShaHash{}, 2}, time.Now()}

	// Create a simple P2PKH pubkey script spendable by Alice. For simplicity
	// all of Alice's spendable funds will reside in this output.
	satosihPerOutput := int64(btcPerOutput * 1e8)
	walletAddr, err := btcutil.NewAddressPubKey(privKey.PubKey().SerializeCompressed(),
		ActiveNetParams)
	if err != nil {
		return err
	}
	walletScriptCredit, err := txscript.PayToAddrScript(walletAddr.AddressPubKeyHash())
	if err != nil {
		return err
	}

	// Create numOutputs outputs spendable by our wallet each holding btcPerOutput
	// in satoshis.
	for i := 0; i < numOutputs; i++ {
		tx := wire.NewMsgTx()
		prevOut := wire.NewOutPoint(&wire.ShaHash{}, ^uint32(0))
		txIn := wire.NewTxIn(prevOut, []byte{txscript.OP_0, txscript.OP_0})
		tx.AddTxIn(txIn)
		tx.AddTxOut(wire.NewTxOut(satosihPerOutput, walletScriptCredit))

		txCredit, err := wtxmgr.NewTxRecordFromMsgTx(tx, time.Now())
		if err != nil {
			return err
		}

		if err := addTestTx(w, txCredit, &blk); err != nil {
			return err
		}
	}

	return nil
}

// createTestWallet creates a test LightningWallet will a total of 20BTC
// available for funding channels.
func createTestWallet() (string, *LightningWallet, error) {
	privPass := []byte("private-test")
	tempTestDir, err := ioutil.TempDir("", "lnwallet")
	if err != nil {
		return "", nil, nil
	}

	wallet, err := NewLightningWallet(privPass, nil, testHdSeed, tempTestDir)
	if err != nil {
		return "", nil, err
	}
	fmt.Println("STARTING WALLET")
	wallet.Start()
	fmt.Println("WALLET STARTED")

	// Load our test wallet with 5 outputs each holding 4BTC.
	fmt.Println("loading credits")
	if err := loadTestCredits(wallet, 5, 4); err != nil {
		return "", nil, err
	}
	fmt.Println("credits loaded")

	return tempTestDir, wallet, nil
}

func TestBasicWalletReservationWorkFlow(t *testing.T) {
	// all stages
	// fields on struct properly set
	// funding transaction on disk
}

func TestFundingTransactiontxFees(t *testing.T) {
}

func TestFundingTransactionLockedOutputs(t *testing.T) {
}

func TestFundingTransactionCancellationFreeOutputs(t *testing.T) {
}

func TestFundingReservationInsufficientFunds(t *testing.T) {
}

func TestFundingReservationInvalidCounterpartySigs(t *testing.T) {
}