package main

import (
	"bytes"
	"fmt"
	"runtime/debug"
	"strings"
	"testing"

	"golang.org/x/net/context"

	"github.com/lightningnetwork/lnd/lnrpc"
	"github.com/roasbeef/btcd/rpctest"
	"github.com/roasbeef/btcd/wire"
	"github.com/roasbeef/btcrpcclient"
	"github.com/roasbeef/btcutil"
)

type lndTestCase func(net *networkHarness, t *testing.T)

func assertTxInBlock(block *btcutil.Block, txid *wire.ShaHash, t *testing.T) {
	for _, tx := range block.Transactions() {
		if bytes.Equal(txid[:], tx.Sha()[:]) {
			return
		}
	}

	t.Fatalf("funding tx was not included in block")
}

// testBasicChannelFunding performs a test excercising expected behavior from a
// basic funding workflow. The test creates a new channel between Alice and
// Bob, then immediately closes the channel after asserting some expected post
// conditions. Finally, the chain itelf is checked to ensure the closing
// transaction was mined.
// TODO(roasbeef): abstract blocking calls to async events to methods within
// the networkHarness.
func testBasicChannelFunding(net *networkHarness, t *testing.T) {
	// First establish a channel between Alice and Bob.
	ctxb := context.Background()
	openReq := &lnrpc.OpenChannelRequest{
		// TODO(roasbeef): should pass actual id instead, will fail if
		// more connections added for Alice.
		TargetPeerId:        1,
		LocalFundingAmount:  btcutil.SatoshiPerBitcoin / 2,
		RemoteFundingAmount: 0,
		NumConfs:            1,
	}
	respStream, err := net.AliceClient.OpenChannel(ctxb, openReq)
	if err != nil {
		t.Fatalf("unable to open channel between alice and bob: %v", err)
	}

	// Consume the "channel pending" update. This allows us to synchronize
	// the node's state with the actions below.
	resp, err := respStream.Recv()
	if err != nil {
		t.Fatalf("unable to read rpc resp: %v", err)
	}
	if _, ok := resp.Update.(*lnrpc.OpenStatusUpdate_ChanPending); !ok {
		t.Fatalf("expected channel pending update, instead got %v", resp)
	}

	// Mine a block, the funding txid should be included, and both nodes should
	// be aware of the channel.
	blockHash, err := net.Miner.Node.Generate(1)
	if err != nil {
		t.Fatalf("unable to generate block: %v", err)
	}
	block, err := net.Miner.Node.GetBlock(blockHash[0])
	if err != nil {
		t.Fatalf("unable to get block: %v", err)
	}
	if len(block.Transactions()) < 2 {
		t.Fatalf("funding transaction not included")
	}

	// Next, consume the "channel open" update to reveal the proper
	// outpoint for the final funding transaction.
	resp, err = respStream.Recv()
	if err != nil {
		t.Fatalf("unable to read rpc resp: %v", err)
	}
	fundingResp, ok := resp.Update.(*lnrpc.OpenStatusUpdate_ChanOpen)
	if !ok {
		t.Fatalf("expected channel open update, instead got %v", resp)
	}
	fundingChanPoint := fundingResp.ChanOpen.ChannelPoint
	fundingTxID, _ := wire.NewShaHash(fundingChanPoint.FundingTxid)
	assertTxInBlock(block, fundingTxID, t)

	// TODO(roasbeef): remove and use "listchannels" command after
	// implemented.
	req := &lnrpc.ListPeersRequest{}
	alicePeerInfo, err := net.AliceClient.ListPeers(ctxb, req)
	if err != nil {
		t.Fatalf("unable to list alice peers: %v", err)
	}
	bobPeerInfo, err := net.BobClient.ListPeers(ctxb, req)
	if err != nil {
		t.Fatalf("unable to list bob peers: %v", err)
	}

	// The channel should be listed in the peer information returned by
	// both peers.
	aliceChannels := alicePeerInfo.Peers[0].Channels
	if len(aliceChannels) < 1 {
		t.Fatalf("alice should have an active channel, instead have %v",
			len(aliceChannels))
	}
	bobChannels := bobPeerInfo.Peers[0].Channels
	if len(bobChannels) < 1 {
		t.Fatalf("bob should have an active channel, instead have %v",
			len(bobChannels))
	}
	aliceTxID := alicePeerInfo.Peers[0].Channels[0].ChannelPoint
	bobTxID := bobPeerInfo.Peers[0].Channels[0].ChannelPoint
	fundingTxIDStr := fundingTxID.String()
	if !strings.Contains(bobTxID, fundingTxIDStr) {
		t.Fatalf("alice's channel not found")
	}
	if !strings.Contains(aliceTxID, fundingTxIDStr) {
		t.Fatalf("bob's channel not found")
	}

	// Initiate a close from Alice's side.
	closeReq := &lnrpc.CloseChannelRequest{
		ChannelPoint: fundingChanPoint,
	}
	closeRespStream, err := net.AliceClient.CloseChannel(ctxb, closeReq)
	if err != nil {
		t.Fatalf("unable to close channel: %v", err)
	}

	// Consume the "channel close" update in order to wait for the closing
	// transaction to be broadcast, then wait for the closing tx to be seen
	// within the network.
	closeResp, err := closeRespStream.Recv()
	if err != nil {
		t.Fatalf("unable to read rpc resp: %v", err)
	}
	pendingClose, ok := closeResp.Update.(*lnrpc.CloseStatusUpdate_ClosePending)
	if !ok {
		t.Fatalf("expected close pending update, got %v", pendingClose)
	}
	closeTxid, _ := wire.NewShaHash(pendingClose.ClosePending.Txid)
	net.WaitForTxBroadcast(*closeTxid)

	// Finally, generate a single block, wait for the final close status
	// update, then ensure that the closing transaction was included in the
	// block.
	blockHash, err = net.Miner.Node.Generate(1)
	if err != nil {
		t.Fatalf("unable to generate block: %v", err)
	}
	block, err = net.Miner.Node.GetBlock(blockHash[0])
	if err != nil {
		t.Fatalf("unable to get block: %v", err)
	}
	closeResp, err = closeRespStream.Recv()
	if err != nil {
		t.Fatalf("unable to read rpc resp: %v", err)
	}
	closeFin, ok := closeResp.Update.(*lnrpc.CloseStatusUpdate_ChanClose)
	if !ok {
		t.Fatalf("expected channel open update, instead got %v", resp)
	}
	closingTxID, _ := wire.NewShaHash(closeFin.ChanClose.ClosingTxid)
	assertTxInBlock(block, closingTxID, t)
}

var lndTestCases = map[string]lndTestCase{
	"basic funding flow": testBasicChannelFunding,
}

// TestLightningNetworkDaemon performs a series of integration tests amongst a
// programatically driven network of lnd nodes.
func TestLightningNetworkDaemon(t *testing.T) {
	var btcdHarness *rpctest.Harness
	var lightningNetwork *networkHarness
	var currentTest string
	var err error

	defer func() {
		// If one of the integration tests caused a panic within the main
		// goroutine, then tear down all the harnesses in order to avoid
		// any leaked processes.
		if r := recover(); r != nil {
			fmt.Println("recovering from test panic: ", r)
			if err := btcdHarness.TearDown(); err != nil {
				fmt.Println("unable to tear btcd harnesses: ", err)
			}
			if err := lightningNetwork.TearDownAll(); err != nil {
				fmt.Println("unable to tear lnd harnesses: ", err)
			}
			t.Fatalf("test %v panicked: %s", currentTest, debug.Stack())
		}
	}()

	// First create the network harness to gain access to its
	// 'OnTxAccepted' call back.
	lightningNetwork, err = newNetworkHarness(nil)
	if err != nil {
		t.Fatalf("unable to create lightning network harness: %v", err)
	}
	defer lightningNetwork.TearDownAll()

	handlers := &btcrpcclient.NotificationHandlers{
		OnTxAccepted: lightningNetwork.OnTxAccepted,
	}

	// First create an intance of the btcd's rpctest.Harness. This will be
	// used to fund the wallets of the nodes within the test network and to
	// drive blockchain related events within the network.
	btcdHarness, err = rpctest.New(harnessNetParams, handlers, nil)
	if err != nil {
		t.Fatalf("unable to create mining node: %v", err)
	}
	defer btcdHarness.TearDown()
	if err = btcdHarness.SetUp(true, 50); err != nil {
		t.Fatalf("unable to set up mining node: %v", err)
	}
	if err := btcdHarness.Node.NotifyNewTransactions(false); err != nil {
		t.Fatalf("unable to request transaction notifications: %v", err)
	}

	// With the btcd harness created, we can now complete the
	// initialization of the network.
	if err := lightningNetwork.InitializeSeedNodes(btcdHarness); err != nil {
		t.Fatalf("unable to initialize seed nodes: %v", err)
	}
	if err = lightningNetwork.SetUp(); err != nil {
		t.Fatalf("unable to set up test lightning network: %v", err)
	}

	t.Logf("Running %v integration tests", len(lndTestCases))
	for testName, lnTest := range lndTestCases {
		t.Logf("Executing test %v", testName)

		currentTest = testName
		lnTest(lightningNetwork, t)
	}
}