package itest

import (
	"encoding/hex"
	"time"

	"github.com/btcsuite/btcd/btcutil"
	"github.com/lightningnetwork/lnd/chainreg"
	"github.com/lightningnetwork/lnd/lnrpc"
	"github.com/lightningnetwork/lnd/lnrpc/routerrpc"
	"github.com/lightningnetwork/lnd/lntest"
	"github.com/stretchr/testify/require"
)

// testTrackPayments tests whether a client that calls the TrackPayments api
// receives payment updates.
func testTrackPayments(ht *lntest.HarnessTest) {
	// Create Alice with the new flag so she understands the new payment
	// status.
	cfgAlice := []string{"--routerrpc.usestatusinitiated"}
	cfgs := [][]string{cfgAlice, nil}

	// Create a channel Alice->Bob.
	_, nodes := ht.CreateSimpleNetwork(
		cfgs, lntest.OpenChannelParams{
			Amt: btcutil.Amount(300000),
		},
	)
	alice, bob := nodes[0], nodes[1]

	// Call the TrackPayments api to listen for payment updates.
	req := &routerrpc.TrackPaymentsRequest{
		NoInflightUpdates: false,
	}
	tracker := alice.RPC.TrackPayments(req)

	// Create an invoice from bob.
	var amountMsat int64 = 1000
	invoiceResp := bob.RPC.AddInvoice(
		&lnrpc.Invoice{
			ValueMsat: amountMsat,
		},
	)
	invoice := bob.RPC.LookupInvoice(invoiceResp.RHash)

	// Send payment from alice to bob.
	paymentClient := alice.RPC.SendPayment(
		&routerrpc.SendPaymentRequest{
			PaymentRequest: invoice.PaymentRequest,
		},
	)

	// Make sure the payment doesn't error due to invalid parameters or so.
	_, err := paymentClient.Recv()
	require.NoError(ht, err, "unable to get payment update")

	// Assert the first payment update is an initiated update.
	update1, err := tracker.Recv()
	require.NoError(ht, err, "unable to receive payment update 1")

	require.Equal(ht, lnrpc.Payment_INITIATED, update1.Status)
	require.Equal(ht, lnrpc.PaymentFailureReason_FAILURE_REASON_NONE,
		update1.FailureReason)
	require.Equal(ht, invoice.PaymentRequest, update1.PaymentRequest)
	require.Equal(ht, amountMsat, update1.ValueMsat)

	// Assert the first payment update is an inflight update.
	update2, err := tracker.Recv()
	require.NoError(ht, err, "unable to receive payment update 2")

	require.Equal(ht, lnrpc.Payment_IN_FLIGHT, update2.Status)
	require.Equal(ht, lnrpc.PaymentFailureReason_FAILURE_REASON_NONE,
		update2.FailureReason)
	require.Equal(ht, invoice.PaymentRequest, update2.PaymentRequest)
	require.Equal(ht, amountMsat, update2.ValueMsat)

	// Assert the third payment update is a payment success update.
	update3, err := tracker.Recv()
	require.NoError(ht, err, "unable to receive payment update 3")

	require.Equal(ht, lnrpc.Payment_SUCCEEDED, update3.Status)
	require.Equal(ht, lnrpc.PaymentFailureReason_FAILURE_REASON_NONE,
		update3.FailureReason)
	require.Equal(ht, invoice.PaymentRequest, update3.PaymentRequest)
	require.Equal(ht, amountMsat, update3.ValueMsat)
	require.Equal(ht, hex.EncodeToString(invoice.RPreimage),
		update3.PaymentPreimage)
}

// testTrackPaymentsCompatible checks that when `routerrpc.usestatusinitiated`
// is not set, the new Payment_INITIATED is replaced with Payment_IN_FLIGHT.
func testTrackPaymentsCompatible(ht *lntest.HarnessTest) {
	// Open a channel between alice and bob.
	_, nodes := ht.CreateSimpleNetwork(
		[][]string{nil, nil}, lntest.OpenChannelParams{
			Amt: btcutil.Amount(300000),
		},
	)
	alice, bob := nodes[0], nodes[1]

	// Call the TrackPayments api to listen for payment updates.
	req := &routerrpc.TrackPaymentsRequest{
		NoInflightUpdates: false,
	}
	tracker := alice.RPC.TrackPayments(req)

	// Create an invoice from bob.
	var amountMsat int64 = 1000
	invoiceResp := bob.RPC.AddInvoice(
		&lnrpc.Invoice{
			ValueMsat: amountMsat,
		},
	)
	invoice := bob.RPC.LookupInvoice(invoiceResp.RHash)

	// Send payment from alice to bob.
	paymentClient := alice.RPC.SendPayment(
		&routerrpc.SendPaymentRequest{
			PaymentRequest: invoice.PaymentRequest,
		},
	)

	// Assert the first track payment update is an inflight update.
	update1, err := tracker.Recv()
	require.NoError(ht, err, "unable to receive payment update 1")
	require.Equal(ht, lnrpc.Payment_IN_FLIGHT, update1.Status)

	// Assert the first track payment update is an inflight update.
	update2, err := tracker.Recv()
	require.NoError(ht, err, "unable to receive payment update 2")
	require.Equal(ht, lnrpc.Payment_IN_FLIGHT, update2.Status)

	// Assert the third track payment update is a payment success update.
	update3, err := tracker.Recv()
	require.NoError(ht, err, "unable to receive payment update 3")
	require.Equal(ht, lnrpc.Payment_SUCCEEDED, update3.Status)

	// Assert the first payment client update is an inflight update.
	payment1, err := paymentClient.Recv()
	require.NoError(ht, err, "unable to get payment update")
	require.Equal(ht, lnrpc.Payment_IN_FLIGHT, payment1.Status)

	// Assert the second payment client update is an inflight update.
	payment2, err := paymentClient.Recv()
	require.NoError(ht, err, "unable to get payment update")
	require.Equal(ht, lnrpc.Payment_IN_FLIGHT, payment2.Status)

	// Assert the third payment client update is a success update.
	payment3, err := paymentClient.Recv()
	require.NoError(ht, err, "unable to get payment update")
	require.Equal(ht, lnrpc.Payment_SUCCEEDED, payment3.Status)
}

// testSendToRouteFailPaymentNotification tests that when we are failing a
// payment via SendToRouteV2 we only receive one failure notification, also
// making sure the failure reason is not overwritten in our db.
func testSendToRouteFailPaymentNotification(ht *lntest.HarnessTest) {
	// Create a simple network with Alice->Bob.
	_, nodes := ht.CreateSimpleNetwork(
		[][]string{nil, nil},
		lntest.OpenChannelParams{Amt: 100_000},
	)
	alice, bob := nodes[0], nodes[1]

	// Make Bob create an invoice for Alice to pay.
	_, rHashes, _ := ht.CreatePayReqs(bob, paymentAmt, 1)

	rHash := rHashes[0]

	// We create a dummy payment address so that the payment fails at
	// the first hop.
	payAddr := make([]byte, 32)

	// Subscribe to all the payments because otherwise we would not be able
	// to verify if two failure notifications are received. The single
	// subscriber is deleted after receiving the first failure notification.
	tracker := alice.RPC.TrackPayments(&routerrpc.TrackPaymentsRequest{
		NoInflightUpdates: true,
	})

	bobPubKey, err := hex.DecodeString(bob.PubKeyStr)
	require.NoError(ht, err, "unable to decode bob's pubkey")

	// Build a route for the specified hops.
	r := alice.RPC.BuildRoute(&routerrpc.BuildRouteRequest{
		AmtMsat:        int64(paymentAmt * 1000),
		FinalCltvDelta: chainreg.DefaultBitcoinTimeLockDelta,
		HopPubkeys:     [][]byte{bobPubKey},
	}).Route

	// Set the MPP records to indicate this is a payment shard.
	hop := r.Hops[len(r.Hops)-1]
	hop.MppRecord = &lnrpc.MPPRecord{
		PaymentAddr:  payAddr,
		TotalAmtMsat: int64(paymentAmt * 1000),
	}

	// Send the only shard.
	sendReq := &routerrpc.SendToRouteRequest{
		PaymentHash: rHash,
		Route:       r,
	}

	// We launch the payment and check the payment stream to verify that
	// we are receiving exactly one failure notification.
	respChan := make(chan *lnrpc.HTLCAttempt, 1)
	go func() {
		attempt := alice.RPC.SendToRouteV2(sendReq)
		respChan <- attempt
	}()

	// We excpect the attempt and the payment to fail.
	select {
	case attempt := <-respChan:
		require.Equal(ht, attempt.Status, lnrpc.HTLCAttempt_FAILED)

	case <-time.After(defaultTimeout):
		ht.Fatal("timeout waiting for SendToRouteV2 response")
	}

	// Assert the first track payment update should be a failed update.
	update, err := tracker.Recv()
	require.NoError(ht, err, "unable to receive payment update")
	require.Equal(ht, lnrpc.Payment_FAILED, update.Status)

	// Now check no other notifications come in.
	notifChan := make(chan *lnrpc.Payment, 1)
	go func() {
		notif, err := tracker.Recv()
		if err != nil {
			return
		}

		notifChan <- notif
	}()

	// We do not expect any other notifications.
	select {
	case unexpectedNotif := <-notifChan:
		ht.Fatalf("received unexpected notification: %v",
			unexpectedNotif)

	case <-time.After(100 * time.Millisecond):
	}
}