package itest

import (
	"fmt"
	"testing"

	"github.com/btcsuite/btcd/btcjson"
	"github.com/btcsuite/btcd/btcutil"
	"github.com/btcsuite/btcd/chaincfg/chainhash"
	"github.com/btcsuite/btcd/integration/rpctest"
	"github.com/lightningnetwork/lnd/chainreg"
	"github.com/lightningnetwork/lnd/funding"
	"github.com/lightningnetwork/lnd/lnrpc"
	"github.com/lightningnetwork/lnd/lntest"
	"github.com/lightningnetwork/lnd/lntest/node"
	"github.com/lightningnetwork/lnd/lntest/rpc"
	"github.com/lightningnetwork/lnd/lntest/wait"
	"github.com/stretchr/testify/require"
)

// testOpenChannelAfterReorg tests that in the case where we have an open
// channel where the funding tx gets reorged out, the channel will no
// longer be present in the node's routing table.
func testOpenChannelAfterReorg(ht *lntest.HarnessTest) {
	// Skip test for neutrino, as we cannot disconnect the miner at will.
	// TODO(halseth): remove when either can disconnect at will, or restart
	// node with connection to new miner.
	if ht.IsNeutrinoBackend() {
		ht.Skipf("skipping reorg test for neutrino backend")
	}

	temp := "temp"

	// Set up a new miner that we can use to cause a reorg.
	tempLogDir := ".tempminerlogs"
	logFilename := "output-open_channel_reorg-temp_miner.log"
	tempMiner := lntest.NewTempMiner(
		ht.Context(), ht.T, tempLogDir, logFilename,
	)
	defer tempMiner.Stop()

	// Setup the temp miner
	require.NoError(ht, tempMiner.SetUp(false, 0),
		"unable to set up mining node")

	miner := ht.Miner
	alice, bob := ht.Alice, ht.Bob

	// We start by connecting the new miner to our original miner,
	// such that it will sync to our original chain.
	err := miner.Client.Node(
		btcjson.NConnect, tempMiner.P2PAddress(), &temp,
	)
	require.NoError(ht, err, "unable to connect miners")

	nodeSlice := []*rpctest.Harness{miner.Harness, tempMiner.Harness}
	err = rpctest.JoinNodes(nodeSlice, rpctest.Blocks)
	require.NoError(ht, err, "unable to join node on blocks")

	// The two miners should be on the same blockheight.
	assertMinerBlockHeightDelta(ht, miner, tempMiner, 0)

	// We disconnect the two miners, such that we can mine two different
	// chains and can cause a reorg later.
	err = miner.Client.Node(
		btcjson.NDisconnect, tempMiner.P2PAddress(), &temp,
	)
	require.NoError(ht, err, "unable to disconnect miners")

	// Create a new channel that requires 1 confs before it's considered
	// open, then broadcast the funding transaction
	params := lntest.OpenChannelParams{
		Amt:     funding.MaxBtcFundingAmount,
		Private: true,
	}
	pendingUpdate := ht.OpenChannelAssertPending(alice, bob, params)

	// Wait for miner to have seen the funding tx. The temporary miner is
	// disconnected, and won't see the transaction.
	ht.Miner.AssertNumTxsInMempool(1)

	// At this point, the channel's funding transaction will have been
	// broadcast, but not confirmed, and the channel should be pending.
	ht.AssertNodesNumPendingOpenChannels(alice, bob, 1)

	fundingTxID, err := chainhash.NewHash(pendingUpdate.Txid)
	require.NoError(ht, err, "convert funding txid into chainhash failed")

	// We now cause a fork, by letting our original miner mine 10 blocks,
	// and our new miner mine 15. This will also confirm our pending
	// channel on the original miner's chain, which should be considered
	// open.
	block := ht.MineBlocks(10)[0]
	ht.Miner.AssertTxInBlock(block, fundingTxID)
	_, err = tempMiner.Client.Generate(15)
	require.NoError(ht, err, "unable to generate blocks")

	// Ensure the chain lengths are what we expect, with the temp miner
	// being 5 blocks ahead.
	assertMinerBlockHeightDelta(ht, miner, tempMiner, 5)

	chanPoint := &lnrpc.ChannelPoint{
		FundingTxid: &lnrpc.ChannelPoint_FundingTxidBytes{
			FundingTxidBytes: pendingUpdate.Txid,
		},
		OutputIndex: pendingUpdate.OutputIndex,
	}

	// Ensure channel is no longer pending.
	ht.AssertNodesNumPendingOpenChannels(alice, bob, 0)

	// Wait for Alice and Bob to recognize and advertise the new channel
	// generated above.
	ht.AssertTopologyChannelOpen(alice, chanPoint)
	ht.AssertTopologyChannelOpen(bob, chanPoint)

	// Alice should now have 1 edge in her graph.
	ht.AssertNumEdges(alice, 1, true)

	// Now we disconnect Alice's chain backend from the original miner, and
	// connect the two miners together. Since the temporary miner knows
	// about a longer chain, both miners should sync to that chain.
	ht.DisconnectMiner()

	// Connecting to the temporary miner should now cause our original
	// chain to be re-orged out.
	err = miner.Client.Node(btcjson.NConnect, tempMiner.P2PAddress(), &temp)
	require.NoError(ht, err, "unable to connect temp miner")

	nodes := []*rpctest.Harness{tempMiner.Harness, miner.Harness}
	err = rpctest.JoinNodes(nodes, rpctest.Blocks)
	require.NoError(ht, err, "unable to join node on blocks")

	// Once again they should be on the same chain.
	assertMinerBlockHeightDelta(ht, miner, tempMiner, 0)

	// Now we disconnect the two miners, and connect our original miner to
	// our chain backend once again.
	err = miner.Client.Node(
		btcjson.NDisconnect, tempMiner.P2PAddress(), &temp,
	)
	require.NoError(ht, err, "unable to disconnect temp miner")

	ht.ConnectMiner()

	// This should have caused a reorg, and Alice should sync to the longer
	// chain, where the funding transaction is not confirmed.
	_, tempMinerHeight, err := tempMiner.Client.GetBestBlock()
	require.NoError(ht, err, "unable to get current blockheight")
	ht.WaitForNodeBlockHeight(alice, tempMinerHeight)

	// Since the fundingtx was reorged out, Alice should now have no edges
	// in her graph.
	ht.AssertNumEdges(alice, 0, true)

	// Cleanup by mining the funding tx again, then closing the channel.
	block = ht.MineBlocksAndAssertNumTxes(1, 1)[0]
	ht.Miner.AssertTxInBlock(block, fundingTxID)

	ht.CloseChannel(alice, chanPoint)
}

// testOpenChannelFeePolicy checks if different channel fee scenarios are
// correctly handled when the optional channel fee parameters baseFee and
// feeRate are provided. If the OpenChannelRequest is not provided with a value
// for baseFee/feeRate the expectation is that the default baseFee/feeRate is
// applied.
//
//  1. No params provided to OpenChannelRequest:
//     ChannelUpdate --> defaultBaseFee, defaultFeeRate
//  2. Only baseFee provided to OpenChannelRequest:
//     ChannelUpdate --> provided baseFee, defaultFeeRate
//  3. Only feeRate provided to OpenChannelRequest:
//     ChannelUpdate --> defaultBaseFee, provided FeeRate
//  4. baseFee and feeRate provided to OpenChannelRequest:
//     ChannelUpdate --> provided baseFee, provided feeRate
//  5. Both baseFee and feeRate are set to a value lower than the default:
//     ChannelUpdate --> provided baseFee, provided feeRate
func testOpenChannelUpdateFeePolicy(ht *lntest.HarnessTest) {
	const (
		defaultBaseFee       = 1000
		defaultFeeRate       = 1
		defaultTimeLockDelta = chainreg.DefaultBitcoinTimeLockDelta
		defaultMinHtlc       = 1000
		optionalBaseFee      = 1337
		optionalFeeRate      = 1337
		lowBaseFee           = 0
		lowFeeRate           = 900
	)

	defaultMaxHtlc := lntest.CalculateMaxHtlc(funding.MaxBtcFundingAmount)

	chanAmt := funding.MaxBtcFundingAmount
	pushAmt := chanAmt / 2

	feeScenarios := []lntest.OpenChannelParams{
		{
			Amt:        chanAmt,
			PushAmt:    pushAmt,
			UseBaseFee: false,
			UseFeeRate: false,
		},
		{
			Amt:        chanAmt,
			PushAmt:    pushAmt,
			BaseFee:    optionalBaseFee,
			UseBaseFee: true,
			UseFeeRate: false,
		},
		{
			Amt:        chanAmt,
			PushAmt:    pushAmt,
			FeeRate:    optionalFeeRate,
			UseBaseFee: false,
			UseFeeRate: true,
		},
		{
			Amt:        chanAmt,
			PushAmt:    pushAmt,
			BaseFee:    optionalBaseFee,
			FeeRate:    optionalFeeRate,
			UseBaseFee: true,
			UseFeeRate: true,
		},
		{
			Amt:        chanAmt,
			PushAmt:    pushAmt,
			BaseFee:    lowBaseFee,
			FeeRate:    lowFeeRate,
			UseBaseFee: true,
			UseFeeRate: true,
		},
	}

	expectedPolicies := []lnrpc.RoutingPolicy{
		{
			FeeBaseMsat:      defaultBaseFee,
			FeeRateMilliMsat: defaultFeeRate,
			TimeLockDelta:    defaultTimeLockDelta,
			MinHtlc:          defaultMinHtlc,
			MaxHtlcMsat:      defaultMaxHtlc,
		},
		{
			FeeBaseMsat:      optionalBaseFee,
			FeeRateMilliMsat: defaultFeeRate,
			TimeLockDelta:    defaultTimeLockDelta,
			MinHtlc:          defaultMinHtlc,
			MaxHtlcMsat:      defaultMaxHtlc,
		},
		{
			FeeBaseMsat:      defaultBaseFee,
			FeeRateMilliMsat: optionalFeeRate,
			TimeLockDelta:    defaultTimeLockDelta,
			MinHtlc:          defaultMinHtlc,
			MaxHtlcMsat:      defaultMaxHtlc,
		},
		{
			FeeBaseMsat:      optionalBaseFee,
			FeeRateMilliMsat: optionalFeeRate,
			TimeLockDelta:    defaultTimeLockDelta,
			MinHtlc:          defaultMinHtlc,
			MaxHtlcMsat:      defaultMaxHtlc,
		},
		{
			FeeBaseMsat:      lowBaseFee,
			FeeRateMilliMsat: lowFeeRate,
			TimeLockDelta:    defaultTimeLockDelta,
			MinHtlc:          defaultMinHtlc,
			MaxHtlcMsat:      defaultMaxHtlc,
		},
	}

	bobExpectedPolicy := lnrpc.RoutingPolicy{
		FeeBaseMsat:      defaultBaseFee,
		FeeRateMilliMsat: defaultFeeRate,
		TimeLockDelta:    defaultTimeLockDelta,
		MinHtlc:          defaultMinHtlc,
		MaxHtlcMsat:      defaultMaxHtlc,
	}

	// In this basic test, we'll need a third node, Carol, so we can forward
	// a payment through the channel we'll open with the different fee
	// policies.
	carol := ht.NewNode("Carol", nil)

	alice, bob := ht.Alice, ht.Bob
	nodes := []*node.HarnessNode{alice, bob, carol}

	runTestCase := func(ht *lntest.HarnessTest,
		chanParams lntest.OpenChannelParams,
		alicePolicy, bobPolicy *lnrpc.RoutingPolicy) {

		// Create a channel Alice->Bob.
		chanPoint := ht.OpenChannel(alice, bob, chanParams)
		defer ht.CloseChannel(alice, chanPoint)

		// Create a channel Carol->Alice.
		chanPoint2 := ht.OpenChannel(
			carol, alice, lntest.OpenChannelParams{
				Amt: 500000,
			},
		)
		defer ht.CloseChannel(carol, chanPoint2)

		// Alice and Bob should see each other's ChannelUpdates,
		// advertising the preferred routing policies.
		assertNodesPolicyUpdate(
			ht, nodes, alice, alicePolicy, chanPoint,
		)
		assertNodesPolicyUpdate(ht, nodes, bob, bobPolicy, chanPoint)

		// They should now know about the default policies.
		for _, n := range nodes {
			ht.AssertChannelPolicy(
				n, alice.PubKeyStr, alicePolicy, chanPoint,
			)
			ht.AssertChannelPolicy(
				n, bob.PubKeyStr, bobPolicy, chanPoint,
			)
		}

		// We should be able to forward a payment from Carol to Bob
		// through the new channel we opened.
		payReqs, _, _ := ht.CreatePayReqs(bob, paymentAmt, 1)
		ht.CompletePaymentRequests(carol, payReqs)
	}

	for i, feeScenario := range feeScenarios {
		ht.Run(fmt.Sprintf("%d", i), func(t *testing.T) {
			st := ht.Subtest(t)
			st.EnsureConnected(alice, bob)

			st.RestartNode(carol)

			// Because we're using ht.Subtest(), we need to restart
			// any node we have to refresh its runtime context.
			// Otherwise, we'll get a "context canceled" error on
			// RPC calls.
			st.EnsureConnected(alice, carol)

			// Send Carol enough coins to be able to open a channel
			// to Alice.
			ht.FundCoins(btcutil.SatoshiPerBitcoin, carol)

			runTestCase(
				st, feeScenario,
				&expectedPolicies[i], &bobExpectedPolicy,
			)
		})
	}
}

// testBasicChannelCreationAndUpdates tests multiple channel opening and
// closing, and ensures that if a node is subscribed to channel updates they
// will be received correctly for both cooperative and force closed channels.
func testBasicChannelCreationAndUpdates(ht *lntest.HarnessTest) {
	runBasicChannelCreationAndUpdates(ht, ht.Alice, ht.Bob)
}

// runBasicChannelCreationAndUpdates tests multiple channel opening and closing,
// and ensures that if a node is subscribed to channel updates they will be
// received correctly for both cooperative and force closed channels.
func runBasicChannelCreationAndUpdates(ht *lntest.HarnessTest,
	alice, bob *node.HarnessNode) {

	const (
		numChannels = 2
		amount      = funding.MaxBtcFundingAmount
	)

	// Subscribe Bob and Alice to channel event notifications.
	bobChanSub := bob.RPC.SubscribeChannelEvents()
	aliceChanSub := alice.RPC.SubscribeChannelEvents()

	// Open the channels between Alice and Bob, asserting that the channels
	// have been properly opened on-chain.
	chanPoints := make([]*lnrpc.ChannelPoint, numChannels)
	for i := 0; i < numChannels; i++ {
		chanPoints[i] = ht.OpenChannel(
			alice, bob, lntest.OpenChannelParams{
				Amt: amount,
			},
		)
	}

	// Since each of the channels just became open, Bob and Alice should
	// each receive an open and an active notification for each channel.
	const numExpectedOpenUpdates = 3 * numChannels
	verifyOpenUpdatesReceived := func(sub rpc.ChannelEventsClient) error {
		for i := 0; i < numExpectedOpenUpdates; i++ {
			update := ht.ReceiveChannelEvent(sub)

			switch update.Type {
			case lnrpc.ChannelEventUpdate_PENDING_OPEN_CHANNEL:
				if i%3 == 0 {
					continue
				}

				return fmt.Errorf("expected open or active" +
					"channel ntfn, got pending open " +
					"channel ntfn instead")

			case lnrpc.ChannelEventUpdate_OPEN_CHANNEL:
				if i%3 == 1 {
					continue
				}

				return fmt.Errorf("expected pending open or " +
					"active channel ntfn, got open" +
					"channel ntfn instead")

			case lnrpc.ChannelEventUpdate_ACTIVE_CHANNEL:
				if i%3 == 2 {
					continue
				}

				return fmt.Errorf("expected pending open or " +
					"open channel ntfn, got active " +
					"channel ntfn instead")

			default:
				return fmt.Errorf("update type mismatch: "+
					"expected open or active channel "+
					"notification, got: %v", update.Type)
			}
		}

		return nil
	}

	require.NoError(ht, verifyOpenUpdatesReceived(bobChanSub),
		"bob open channels")
	require.NoError(ht, verifyOpenUpdatesReceived(aliceChanSub),
		"alice open channels")

	// Close the channels between Alice and Bob, asserting that the
	// channels have been properly closed on-chain.
	for i, chanPoint := range chanPoints {
		// Force close the first of the two channels.
		force := i%2 == 0
		if force {
			ht.ForceCloseChannel(alice, chanPoint)
		} else {
			ht.CloseChannel(alice, chanPoint)
		}
	}

	// verifyCloseUpdatesReceived is used to verify that Alice and Bob
	// receive the correct channel updates in order.
	const numExpectedCloseUpdates = 3 * numChannels
	verifyCloseUpdatesReceived := func(sub rpc.ChannelEventsClient,
		forceType lnrpc.ChannelCloseSummary_ClosureType,
		closeInitiator lnrpc.Initiator) error {

		// Ensure one inactive and one closed notification is received
		// for each closed channel.
		for i := 0; i < numExpectedCloseUpdates; i++ {
			expectedCloseType := lnrpc.
				ChannelCloseSummary_COOPERATIVE_CLOSE

			// Every other channel should be force closed. If this
			// channel was force closed, set the expected close type
			// to the type passed in.
			force := (i/3)%2 == 0
			if force {
				expectedCloseType = forceType
			}

			chanUpdate := ht.ReceiveChannelEvent(sub)
			err := verifyCloseUpdate(
				chanUpdate, expectedCloseType,
				closeInitiator,
			)
			if err != nil {
				return err
			}
		}

		return nil
	}

	// Verify Bob receives all closed channel notifications. He should
	// receive a remote force close notification for force closed channels.
	// All channels (cooperatively and force closed) should have a remote
	// close initiator because Alice closed the channels.
	require.NoError(
		ht, verifyCloseUpdatesReceived(
			bobChanSub,
			lnrpc.ChannelCloseSummary_REMOTE_FORCE_CLOSE,
			lnrpc.Initiator_INITIATOR_REMOTE,
		), "verifying bob close updates",
	)

	// Verify Alice receives all closed channel notifications. She should
	// receive a remote force close notification for force closed channels.
	// All channels (cooperatively and force closed) should have a local
	// close initiator because Alice closed the channels.
	require.NoError(
		ht, verifyCloseUpdatesReceived(
			aliceChanSub,
			lnrpc.ChannelCloseSummary_LOCAL_FORCE_CLOSE,
			lnrpc.Initiator_INITIATOR_LOCAL,
		), "verifying alice close updates",
	)
}

// assertMinerBlockHeightDelta ensures that tempMiner is 'delta' blocks ahead
// of miner.
func assertMinerBlockHeightDelta(ht *lntest.HarnessTest,
	miner, tempMiner *lntest.HarnessMiner, delta int32) {

	// Ensure the chain lengths are what we expect.
	err := wait.NoError(func() error {
		_, tempMinerHeight, err := tempMiner.Client.GetBestBlock()
		if err != nil {
			return fmt.Errorf("unable to get current "+
				"blockheight %v", err)
		}

		_, minerHeight, err := miner.Client.GetBestBlock()
		if err != nil {
			return fmt.Errorf("unable to get current "+
				"blockheight %v", err)
		}

		if tempMinerHeight != minerHeight+delta {
			return fmt.Errorf("expected new miner(%d) to be %d "+
				"blocks ahead of original miner(%d)",
				tempMinerHeight, delta, minerHeight)
		}

		return nil
	}, defaultTimeout)
	require.NoError(ht, err, "failed to assert block height delta")
}

// verifyCloseUpdate is used to verify that a closed channel update is of the
// expected type.
func verifyCloseUpdate(chanUpdate *lnrpc.ChannelEventUpdate,
	closeType lnrpc.ChannelCloseSummary_ClosureType,
	closeInitiator lnrpc.Initiator) error {

	// We should receive one inactive and one closed notification
	// for each channel.
	switch update := chanUpdate.Channel.(type) {
	case *lnrpc.ChannelEventUpdate_InactiveChannel:
		if chanUpdate.Type !=
			lnrpc.ChannelEventUpdate_INACTIVE_CHANNEL {

			return fmt.Errorf("update type mismatch: "+
				"expected %v, got %v",
				lnrpc.ChannelEventUpdate_INACTIVE_CHANNEL,
				chanUpdate.Type)
		}

	case *lnrpc.ChannelEventUpdate_ClosedChannel:
		if chanUpdate.Type !=
			lnrpc.ChannelEventUpdate_CLOSED_CHANNEL {

			return fmt.Errorf("update type mismatch: "+
				"expected %v, got %v",
				lnrpc.ChannelEventUpdate_CLOSED_CHANNEL,
				chanUpdate.Type)
		}

		if update.ClosedChannel.CloseType != closeType {
			return fmt.Errorf("channel closure type "+
				"mismatch: expected %v, got %v",
				closeType,
				update.ClosedChannel.CloseType)
		}

		if update.ClosedChannel.CloseInitiator != closeInitiator {
			return fmt.Errorf("expected close intiator: %v, "+
				"got: %v", closeInitiator,
				update.ClosedChannel.CloseInitiator)
		}

	case *lnrpc.ChannelEventUpdate_FullyResolvedChannel:
		if chanUpdate.Type !=
			lnrpc.ChannelEventUpdate_FULLY_RESOLVED_CHANNEL {

			return fmt.Errorf("update type mismatch: "+
				"expected %v, got %v",
				lnrpc.ChannelEventUpdate_FULLY_RESOLVED_CHANNEL,
				chanUpdate.Type)
		}

	default:
		return fmt.Errorf("channel update channel of wrong type, "+
			"expected closed channel, got %T",
			update)
	}

	return nil
}