package unittest

import (
	"fmt"
	"os/exec"
	"path/filepath"
	"testing"
	"time"

	"github.com/btcsuite/btcd/chaincfg"
	"github.com/btcsuite/btcd/integration/rpctest"
	"github.com/btcsuite/btcwallet/chain"
	"github.com/btcsuite/btcwallet/walletdb"
	"github.com/lightninglabs/neutrino"
	"github.com/lightningnetwork/lnd/kvdb"
	"github.com/lightningnetwork/lnd/lntest/port"
	"github.com/lightningnetwork/lnd/lntest/wait"
	"github.com/stretchr/testify/require"
)

var (
	// TrickleInterval is the interval at which the miner should trickle
	// transactions to its peers. We'll set it small to ensure the miner
	// propagates transactions quickly in the tests.
	TrickleInterval = 10 * time.Millisecond
)

var (
	// NetParams are the default network parameters for the tests.
	NetParams = &chaincfg.RegressionNetParams
)

// NewMiner spawns testing harness backed by a btcd node that can serve as a
// miner.
func NewMiner(t *testing.T, netParams *chaincfg.Params, extraArgs []string,
	createChain bool, spendableOutputs uint32) *rpctest.Harness {

	t.Helper()

	// Add the trickle interval argument to the extra args.
	trickle := fmt.Sprintf("--trickleinterval=%v", TrickleInterval)
	extraArgs = append(extraArgs, trickle)

	node, err := rpctest.New(netParams, nil, extraArgs, "")
	require.NoError(t, err, "unable to create backend node")
	t.Cleanup(func() {
		require.NoError(t, node.TearDown())
	})

	// We want to overwrite some of the connection settings to make the
	// tests more robust. We might need to restart the backend while there
	// are already blocks present, which will take a bit longer than the
	// 1 second the default settings amount to. Doubling both values will
	// give us retries up to 4 seconds.
	node.MaxConnRetries = rpctest.DefaultMaxConnectionRetries * 2
	node.ConnectionRetryTimeout = rpctest.DefaultConnectionRetryTimeout * 2

	if err := node.SetUp(createChain, spendableOutputs); err != nil {
		t.Fatalf("unable to set up backend node: %v", err)
	}

	// Next mine enough blocks in order for segwit and the CSV package
	// soft-fork to activate.
	numBlocks := netParams.MinerConfirmationWindow*2 + 17
	_, err = node.Client.Generate(numBlocks)
	require.NoError(t, err, "failed to generate blocks")

	return node
}

// NewBitcoindBackend spawns a new bitcoind node that connects to a miner at the
// specified address. The txindex boolean can be set to determine whether the
// backend node should maintain a transaction index. The rpcpolling boolean
// can be set to determine whether bitcoind's RPC polling interface should be
// used for block and tx notifications or if its ZMQ interface should be used.
// A connection to the newly spawned bitcoind node is returned.
func NewBitcoindBackend(t *testing.T, netParams *chaincfg.Params,
	minerAddr string, txindex, rpcpolling bool) *chain.BitcoindConn {

	t.Helper()

	tempBitcoindDir := t.TempDir()

	rpcPort := port.NextAvailablePort()
	zmqBlockPort := port.NextAvailablePort()
	zmqTxPort := port.NextAvailablePort()
	zmqBlockHost := fmt.Sprintf("tcp://127.0.0.1:%d", zmqBlockPort)
	zmqTxHost := fmt.Sprintf("tcp://127.0.0.1:%d", zmqTxPort)

	args := []string{
		"-connect=" + minerAddr,
		"-datadir=" + tempBitcoindDir,
		"-regtest",
		"-rpcauth=weks:469e9bb14ab2360f8e226efed5ca6fd$507c670e800a95" +
			"284294edb5773b05544b220110063096c221be9933c82d38e1",
		fmt.Sprintf("-rpcport=%d", rpcPort),
		"-disablewallet",
		"-zmqpubrawblock=" + zmqBlockHost,
		"-zmqpubrawtx=" + zmqTxHost,
	}
	if txindex {
		args = append(args, "-txindex")
	}

	bitcoind := exec.Command("bitcoind", args...)
	if err := bitcoind.Start(); err != nil {
		t.Fatalf("unable to start bitcoind: %v", err)
	}
	t.Cleanup(func() {
		_ = bitcoind.Process.Kill()
		_ = bitcoind.Wait()
	})

	// Wait for the bitcoind instance to start up.
	time.Sleep(time.Second)

	host := fmt.Sprintf("127.0.0.1:%d", rpcPort)
	cfg := &chain.BitcoindConfig{
		ChainParams: netParams,
		Host:        host,
		User:        "weks",
		Pass:        "weks",
		// Fields only required for pruned nodes, not needed for these
		// tests.
		Dialer:             nil,
		PrunedModeMaxPeers: 0,
	}

	if rpcpolling {
		cfg.PollingConfig = &chain.PollingConfig{
			BlockPollingInterval: time.Millisecond * 20,
			TxPollingInterval:    time.Millisecond * 20,
		}
	} else {
		cfg.ZMQConfig = &chain.ZMQConfig{
			ZMQBlockHost:    zmqBlockHost,
			ZMQTxHost:       zmqTxHost,
			ZMQReadDeadline: 5 * time.Second,
		}
	}

	var conn *chain.BitcoindConn
	err := wait.NoError(func() error {
		var err error
		conn, err = chain.NewBitcoindConn(cfg)
		if err != nil {
			return err
		}

		return conn.Start()
	}, 10*time.Second)
	if err != nil {
		t.Fatalf("unable to establish connection to bitcoind at %v: "+
			"%v", tempBitcoindDir, err)
	}
	t.Cleanup(conn.Stop)

	return conn
}

// NewNeutrinoBackend spawns a new neutrino node that connects to a miner at
// the specified address.
func NewNeutrinoBackend(t *testing.T, netParams *chaincfg.Params,
	minerAddr string) *neutrino.ChainService {

	t.Helper()

	spvDir := t.TempDir()

	dbName := filepath.Join(spvDir, "neutrino.db")
	spvDatabase, err := walletdb.Create(
		"bdb", dbName, true, kvdb.DefaultDBTimeout,
	)
	if err != nil {
		t.Fatalf("unable to create walletdb: %v", err)
	}
	t.Cleanup(func() {
		spvDatabase.Close()
	})

	// Create an instance of neutrino connected to the running btcd
	// instance.
	spvConfig := neutrino.Config{
		DataDir:      spvDir,
		Database:     spvDatabase,
		ChainParams:  *netParams,
		ConnectPeers: []string{minerAddr},
	}
	spvNode, err := neutrino.NewChainService(spvConfig)
	if err != nil {
		t.Fatalf("unable to create neutrino: %v", err)
	}

	// We'll also wait for the instance to sync up fully to the chain
	// generated by the btcd instance.
	_ = spvNode.Start()
	for !spvNode.IsCurrent() {
		time.Sleep(time.Millisecond * 100)
	}
	t.Cleanup(func() {
		_ = spvNode.Stop()
	})

	return spvNode
}

func init() {
	// Before we start any node, we need to make sure that any btcd or
	// bitcoind node that is started through the RPC harness uses a unique
	// port as well to avoid any port collisions.
	rpctest.ListenAddressGenerator =
		port.GenerateSystemUniqueListenerAddresses
}