/*
Copyright IBM Corp. All Rights Reserved.

SPDX-License-Identifier: Apache-2.0
*/

package gossip

import (
	"context"
	"crypto/tls"
	"fmt"
	"io"
	"sync"
	"sync/atomic"
	"testing"
	"time"

	"github.com/hyperledger/fabric/common/util"
	"github.com/hyperledger/fabric/core/comm"
	"github.com/hyperledger/fabric/gossip/api"
	"github.com/hyperledger/fabric/gossip/common"
	utilgossip "github.com/hyperledger/fabric/gossip/util"
	proto "github.com/hyperledger/fabric/protos/gossip"
	"github.com/stretchr/testify/assert"
	"google.golang.org/grpc"
)

type peerMock struct {
	pkiID                common.PKIidType
	selfCertHash         []byte
	gRGCserv             *grpc.Server
	finishedSignal       sync.WaitGroup
	expectedMsgs2Receive uint32
	msgReceivedCount     uint32
	msgAssertions        []msgInspection
	t                    *testing.T
}

func (p *peerMock) GossipStream(stream proto.Gossip_GossipStreamServer) error {
	sessionCounter := 0
	for {
		envelope, err := stream.Recv()
		if err == io.EOF {
			return nil
		}
		if err != nil {
			return err
		}
		gMsg, err := envelope.ToGossipMessage()
		if err != nil {
			panic(err)
		}
		if sessionCounter == 0 {
			connEstablishMsg := p.connEstablishMsg(p.pkiID, p.selfCertHash, api.PeerIdentityType(p.pkiID))
			stream.Send(connEstablishMsg.Envelope)
		}
		for _, assertion := range p.msgAssertions {
			assertion(p.t, sessionCounter, &receivedMsg{stream: stream, SignedGossipMessage: gMsg})
		}
		p.t.Log("sessionCounter:", sessionCounter, string(p.pkiID), "got msg:", gMsg)
		sessionCounter++
		atomic.AddUint32(&p.msgReceivedCount, uint32(1))
		if atomic.LoadUint32(&p.msgReceivedCount) == p.expectedMsgs2Receive {
			p.finishedSignal.Done()
		}
	}
}

func (p *peerMock) Ping(context.Context, *proto.Empty) (*proto.Empty, error) {
	return &proto.Empty{}, nil
}

func newPeerMockWithGRPC(port int, gRPCServer *comm.GRPCServer, certs *common.TLSCertificates,
	expectedMsgs2Receive int, t *testing.T, msgAssertions ...msgInspection) *peerMock {
	p := &peerMock{
		gRGCserv:             gRPCServer.Server(),
		msgAssertions:        msgAssertions,
		t:                    t,
		pkiID:                common.PKIidType(fmt.Sprintf("127.0.0.1:%d", port)),
		selfCertHash:         util.ComputeSHA256(certs.TLSServerCert.Load().(*tls.Certificate).Certificate[0]),
		expectedMsgs2Receive: uint32(expectedMsgs2Receive),
	}
	p.finishedSignal.Add(1)
	proto.RegisterGossipServer(gRPCServer.Server(), p)
	go func() {
		gRPCServer.Start()
	}()
	return p
}

func (p *peerMock) connEstablishMsg(pkiID common.PKIidType, hash []byte, cert api.PeerIdentityType) *proto.SignedGossipMessage {
	m := &proto.GossipMessage{
		Tag:   proto.GossipMessage_EMPTY,
		Nonce: 0,
		Content: &proto.GossipMessage_Conn{
			Conn: &proto.ConnEstablish{
				TlsCertHash: hash,
				Identity:    cert,
				PkiId:       pkiID,
			},
		},
	}
	gMsg := &proto.SignedGossipMessage{
		GossipMessage: m,
	}
	gMsg.Sign((&configurableCryptoService{}).Sign)
	return gMsg
}

func (p *peerMock) stop() {
	p.gRGCserv.Stop()
}

type receivedMsg struct {
	*proto.SignedGossipMessage
	stream proto.Gossip_GossipStreamServer
}

func (msg *receivedMsg) respond(message *proto.SignedGossipMessage) {
	msg.stream.Send(message.Envelope)
}

func memResp(nonce uint64, endpoint string) *proto.SignedGossipMessage {
	fakePeerAliveMsg := &proto.SignedGossipMessage{
		GossipMessage: &proto.GossipMessage{
			Tag: proto.GossipMessage_EMPTY,
			Content: &proto.GossipMessage_AliveMsg{
				AliveMsg: &proto.AliveMessage{
					Membership: &proto.Member{
						Endpoint: endpoint,
						PkiId:    []byte(endpoint),
					},
					Identity: []byte(endpoint),
					Timestamp: &proto.PeerTime{
						IncNum: uint64(time.Now().UnixNano()),
						SeqNum: 0,
					},
				},
			},
		},
	}

	m, _ := fakePeerAliveMsg.Sign((&configurableCryptoService{}).Sign)
	sMsg, _ := (&proto.SignedGossipMessage{
		GossipMessage: &proto.GossipMessage{
			Tag:   proto.GossipMessage_EMPTY,
			Nonce: nonce,
			Content: &proto.GossipMessage_MemRes{
				MemRes: &proto.MembershipResponse{
					Alive: []*proto.Envelope{m},
					Dead:  []*proto.Envelope{},
				},
			},
		},
	}).NoopSign()
	return sMsg
}

type msgInspection func(t *testing.T, index int, m *receivedMsg)

func TestAnchorPeer(t *testing.T) {
	t.Parallel()
	defer testWG.Done()
	// Actors:
	// OrgA: {
	// 	p:   a real gossip instance
	//	ap1: anchor peer of type *peerMock
	//	pm1: a *peerMock
	// }
	// OrgB: {
	//	ap2: anchor peer of type *peerMock
	//	pm2: a *peerMock
	// }
	// Scenario:
	// 	Spawn the peer (p) that will be used to connect to the 2 anchor peers.
	//	After 5 seconds, spawn the anchor peers.
	// 	See that the MembershipRequest messages that are sent to the anchor peers
	// 	contain internal endpoints only to the anchor peers that are in orgA.
	//	Each anchor peer tells about a peer in its own organization (pm1 or pm2).
	//	Wait until 'p' sends 3 messages (handshake, handshake + memReq) to each anchor peer
	//	and 1 message (for handshake) to each of pm1 and pm2 to prove that the membership response
	//	was successfully sent from the anchor peers to p.

	cs := &configurableCryptoService{m: make(map[string]api.OrgIdentityType)}
	orgA := "orgA"
	orgB := "orgB"

	port, grpc, cert, secDialOpt, _ := utilgossip.CreateGRPCLayer()
	port1, grpc1, cert1, _, _ := utilgossip.CreateGRPCLayer()
	port2, grpc2, cert2, _, _ := utilgossip.CreateGRPCLayer()
	port3, grpc3, cert3, _, _ := utilgossip.CreateGRPCLayer()
	port4, grpc4, cert4, _, _ := utilgossip.CreateGRPCLayer()

	cs.putInOrg(port, orgA)  // Real peer
	cs.putInOrg(port1, orgA) // Anchor peer mock
	cs.putInOrg(port2, orgB) // Anchor peer mock
	cs.putInOrg(port3, orgA) // peer mock I
	cs.putInOrg(port4, orgB) // peer mock II

	// Create the assertions
	handshake := func(t *testing.T, index int, m *receivedMsg) {
		if index != 0 {
			return
		}
		assert.NotNil(t, m.GetConn())
	}

	memReqWithInternalEndpoint := func(t *testing.T, index int, m *receivedMsg) {
		if m.GetMemReq() == nil {
			return
		}
		assert.True(t, index > 0)
		req := m.GetMemReq()
		am, err := req.SelfInformation.ToGossipMessage()
		assert.NoError(t, err)
		assert.NotEmpty(t, am.GetSecretEnvelope().InternalEndpoint())
		m.respond(memResp(m.Nonce, fmt.Sprintf("127.0.0.1:%d", port3)))
	}

	memReqWithoutInternalEndpoint := func(t *testing.T, index int, m *receivedMsg) {
		if m.GetMemReq() == nil {
			return
		}
		assert.True(t, index > 0)
		req := m.GetMemReq()
		am, err := req.SelfInformation.ToGossipMessage()
		assert.NoError(t, err)
		assert.Nil(t, am.GetSecretEnvelope())
		m.respond(memResp(m.Nonce, fmt.Sprintf("127.0.0.1:%d", port4)))
	}

	// Create peer mocks
	pm1 := newPeerMockWithGRPC(port3, grpc3, cert3, 1, t, handshake)
	defer pm1.stop()
	pm2 := newPeerMockWithGRPC(port4, grpc4, cert4, 1, t, handshake)
	defer pm2.stop()
	jcm := &joinChanMsg{
		members2AnchorPeers: map[string][]api.AnchorPeer{
			orgA: {
				{Host: "127.0.0.1", Port: port1},
			},
			orgB: {
				{Host: "127.0.0.1", Port: port2},
			},
		},
	}
	channel := common.ChainID("TEST")
	endpoint := fmt.Sprintf("127.0.0.1:%d", port)
	// Create the gossip instance (the peer that connects to anchor peers)
	p := newGossipInstanceWithGRPCWithExternalEndpoint(0, port, grpc, cert, secDialOpt, cs, endpoint)
	defer p.Stop()
	p.JoinChan(jcm, channel)
	p.UpdateLedgerHeight(1, channel)

	time.Sleep(time.Second * 5)

	// Create the anchor peers
	ap1 := newPeerMockWithGRPC(port1, grpc1, cert1, 3, t, handshake, memReqWithInternalEndpoint)
	defer ap1.stop()
	ap2 := newPeerMockWithGRPC(port2, grpc2, cert2, 3, t, handshake, memReqWithoutInternalEndpoint)
	defer ap2.stop()

	// Wait until received all expected messages from gossip instance
	ap1.finishedSignal.Wait()
	ap2.finishedSignal.Wait()
	pm1.finishedSignal.Wait()
	pm2.finishedSignal.Wait()
}

func TestBootstrapPeerMisConfiguration(t *testing.T) {
	t.Parallel()
	defer testWG.Done()
	// Scenario:
	// The peer 'p' is a peer in orgA
	// Peers bs1 and bs2 are bootstrap peers.
	// bs1 is in orgB, so p shouldn't connect to it.
	// bs2 is in orgA, so p should connect to it.
	// We test by intercepting *all* messages that bs1 and bs2 get from p, that:
	// 1) At least 3 connection attempts were sent from p to bs1
	// 2) A membership request was sent from p to bs2

	cs := &configurableCryptoService{m: make(map[string]api.OrgIdentityType)}
	orgA := "orgA"
	orgB := "orgB"

	port, grpc, cert, secDialOpt, _ := utilgossip.CreateGRPCLayer()
	fmt.Printf("port %d\n", port)
	port1, grpc1, cert1, secDialOpt, _ := utilgossip.CreateGRPCLayer()
	fmt.Printf("port1 %d\n", port1)
	port2, grpc2, cert2, secDialOpt, _ := utilgossip.CreateGRPCLayer()
	fmt.Printf("port2 %d\n", port2)

	cs.putInOrg(port, orgA)
	cs.putInOrg(port1, orgB)
	cs.putInOrg(port2, orgA)

	onlyHandshakes := func(t *testing.T, index int, m *receivedMsg) {
		// Ensure all messages sent are connection establishment messages
		// that are probing attempts
		assert.NotNil(t, m.GetConn())
		// If the logic we test in this test- fails,
		// the first message would be a membership request,
		// so this assertion would capture it and print a corresponding failure
		assert.Nil(t, m.GetMemReq())
	}
	// Initialize a peer mock that would wait for 3 messages sent to it
	bs1 := newPeerMockWithGRPC(port1, grpc1, cert1, 3, t, onlyHandshakes)
	defer bs1.stop()

	membershipRequestsSent := make(chan struct{}, 100)
	detectMembershipRequest := func(t *testing.T, index int, m *receivedMsg) {
		if m.GetMemReq() != nil {
			membershipRequestsSent <- struct{}{}
		}
	}

	bs2 := newPeerMockWithGRPC(port2, grpc2, cert2, 0, t, detectMembershipRequest)
	defer bs2.stop()

	endpoint := fmt.Sprintf("127.0.0.1:%d", port)
	p := newGossipInstanceWithGRPCWithExternalEndpoint(0, port, grpc, cert, secDialOpt, cs, endpoint, port1, port2)
	defer p.Stop()

	// Wait for 3 handshake attempts from the bootstrap peer from orgB,
	// to prove that the peer did try to probe the bootstrap peer from orgB
	got3Handshakes := make(chan struct{})
	go func() {
		bs1.finishedSignal.Wait()
		got3Handshakes <- struct{}{}
	}()

	select {
	case <-got3Handshakes:
	case <-time.After(time.Second * 15):
		assert.Fail(t, "Didn't detect 3 handshake attempts to the bootstrap peer from orgB")
	}

	select {
	case <-membershipRequestsSent:
	case <-time.After(time.Second * 15):
		assert.Fail(t, "Bootstrap peer didn't receive a membership request from the peer within a timely manner")
	}
}
