// Copyright 2018 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package stream

import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"os"
	"strconv"
	"strings"
	"sync"
	"testing"
	"time"

	"github.com/ethereum/go-ethereum/log"
	"github.com/ethereum/go-ethereum/node"
	"github.com/ethereum/go-ethereum/p2p/enode"
	"github.com/ethereum/go-ethereum/p2p/simulations/adapters"
	p2ptest "github.com/ethereum/go-ethereum/p2p/testing"
	"github.com/ethereum/go-ethereum/swarm/network"
	"github.com/ethereum/go-ethereum/swarm/network/simulation"
	"github.com/ethereum/go-ethereum/swarm/state"
	"github.com/ethereum/go-ethereum/swarm/testutil"
	"golang.org/x/crypto/sha3"
)

func TestStreamerSubscribe(t *testing.T) {
	tester, streamer, _, teardown, err := newStreamerTester(nil)
	if err != nil {
		t.Fatal(err)
	}
	defer teardown()

	stream := NewStream("foo", "", true)
	err = streamer.Subscribe(tester.Nodes[0].ID(), stream, NewRange(0, 0), Top)
	if err == nil || err.Error() != "stream foo not registered" {
		t.Fatalf("Expected error %v, got %v", "stream foo not registered", err)
	}
}

func TestStreamerRequestSubscription(t *testing.T) {
	tester, streamer, _, teardown, err := newStreamerTester(nil)
	if err != nil {
		t.Fatal(err)
	}
	defer teardown()

	stream := NewStream("foo", "", false)
	err = streamer.RequestSubscription(tester.Nodes[0].ID(), stream, &Range{}, Top)
	if err == nil || err.Error() != "stream foo not registered" {
		t.Fatalf("Expected error %v, got %v", "stream foo not registered", err)
	}
}

var (
	hash0         = sha3.Sum256([]byte{0})
	hash1         = sha3.Sum256([]byte{1})
	hash2         = sha3.Sum256([]byte{2})
	hashesTmp     = append(hash0[:], hash1[:]...)
	hashes        = append(hashesTmp, hash2[:]...)
	corruptHashes = append(hashes[:40])
)

type testClient struct {
	t              string
	wait0          chan bool
	wait2          chan bool
	batchDone      chan bool
	receivedHashes map[string][]byte
}

func newTestClient(t string) *testClient {
	return &testClient{
		t:              t,
		wait0:          make(chan bool),
		wait2:          make(chan bool),
		batchDone:      make(chan bool),
		receivedHashes: make(map[string][]byte),
	}
}

func (self *testClient) NeedData(ctx context.Context, hash []byte) func(context.Context) error {
	self.receivedHashes[string(hash)] = hash
	if bytes.Equal(hash, hash0[:]) {
		return func(context.Context) error {
			<-self.wait0
			return nil
		}
	} else if bytes.Equal(hash, hash2[:]) {
		return func(context.Context) error {
			<-self.wait2
			return nil
		}
	}
	return nil
}

func (self *testClient) BatchDone(Stream, uint64, []byte, []byte) func() (*TakeoverProof, error) {
	close(self.batchDone)
	return nil
}

func (self *testClient) Close() {}

type testServer struct {
	t            string
	sessionIndex uint64
}

func newTestServer(t string, sessionIndex uint64) *testServer {
	return &testServer{
		t:            t,
		sessionIndex: sessionIndex,
	}
}

func (s *testServer) SessionIndex() (uint64, error) {
	return s.sessionIndex, nil
}

func (self *testServer) SetNextBatch(from uint64, to uint64) ([]byte, uint64, uint64, *HandoverProof, error) {
	return make([]byte, HashSize), from + 1, to + 1, nil, nil
}

func (self *testServer) GetData(context.Context, []byte) ([]byte, error) {
	return nil, nil
}

func (self *testServer) Close() {
}

func TestStreamerDownstreamSubscribeUnsubscribeMsgExchange(t *testing.T) {
	tester, streamer, _, teardown, err := newStreamerTester(nil)
	if err != nil {
		t.Fatal(err)
	}
	defer teardown()

	streamer.RegisterClientFunc("foo", func(p *Peer, t string, live bool) (Client, error) {
		return newTestClient(t), nil
	})

	node := tester.Nodes[0]

	stream := NewStream("foo", "", true)
	err = streamer.Subscribe(node.ID(), stream, NewRange(5, 8), Top)
	if err != nil {
		t.Fatalf("Expected no error, got %v", err)
	}

	err = tester.TestExchanges(
		p2ptest.Exchange{
			Label: "Subscribe message",
			Expects: []p2ptest.Expect{
				{
					Code: 4,
					Msg: &SubscribeMsg{
						Stream:   stream,
						History:  NewRange(5, 8),
						Priority: Top,
					},
					Peer: node.ID(),
				},
			},
		},
		// trigger OfferedHashesMsg to actually create the client
		p2ptest.Exchange{
			Label: "OfferedHashes message",
			Triggers: []p2ptest.Trigger{
				{
					Code: 1,
					Msg: &OfferedHashesMsg{
						HandoverProof: &HandoverProof{
							Handover: &Handover{},
						},
						Hashes: hashes,
						From:   5,
						To:     8,
						Stream: stream,
					},
					Peer: node.ID(),
				},
			},
			Expects: []p2ptest.Expect{
				{
					Code: 2,
					Msg: &WantedHashesMsg{
						Stream: stream,
						Want:   []byte{5},
						From:   9,
						To:     0,
					},
					Peer: node.ID(),
				},
			},
		},
	)
	if err != nil {
		t.Fatal(err)
	}

	err = streamer.Unsubscribe(node.ID(), stream)
	if err != nil {
		t.Fatalf("Expected no error, got %v", err)
	}

	err = tester.TestExchanges(p2ptest.Exchange{
		Label: "Unsubscribe message",
		Expects: []p2ptest.Expect{
			{
				Code: 0,
				Msg: &UnsubscribeMsg{
					Stream: stream,
				},
				Peer: node.ID(),
			},
		},
	})

	if err != nil {
		t.Fatal(err)
	}
}

func TestStreamerUpstreamSubscribeUnsubscribeMsgExchange(t *testing.T) {
	tester, streamer, _, teardown, err := newStreamerTester(nil)
	if err != nil {
		t.Fatal(err)
	}
	defer teardown()

	stream := NewStream("foo", "", false)

	streamer.RegisterServerFunc("foo", func(p *Peer, t string, live bool) (Server, error) {
		return newTestServer(t, 10), nil
	})

	node := tester.Nodes[0]

	err = tester.TestExchanges(p2ptest.Exchange{
		Label: "Subscribe message",
		Triggers: []p2ptest.Trigger{
			{
				Code: 4,
				Msg: &SubscribeMsg{
					Stream:   stream,
					History:  NewRange(5, 8),
					Priority: Top,
				},
				Peer: node.ID(),
			},
		},
		Expects: []p2ptest.Expect{
			{
				Code: 1,
				Msg: &OfferedHashesMsg{
					Stream: stream,
					HandoverProof: &HandoverProof{
						Handover: &Handover{},
					},
					Hashes: make([]byte, HashSize),
					From:   6,
					To:     9,
				},
				Peer: node.ID(),
			},
		},
	})

	if err != nil {
		t.Fatal(err)
	}

	err = tester.TestExchanges(p2ptest.Exchange{
		Label: "unsubscribe message",
		Triggers: []p2ptest.Trigger{
			{
				Code: 0,
				Msg: &UnsubscribeMsg{
					Stream: stream,
				},
				Peer: node.ID(),
			},
		},
	})

	if err != nil {
		t.Fatal(err)
	}
}

func TestStreamerUpstreamSubscribeUnsubscribeMsgExchangeLive(t *testing.T) {
	tester, streamer, _, teardown, err := newStreamerTester(nil)
	if err != nil {
		t.Fatal(err)
	}
	defer teardown()

	stream := NewStream("foo", "", true)

	streamer.RegisterServerFunc("foo", func(p *Peer, t string, live bool) (Server, error) {
		return newTestServer(t, 0), nil
	})

	node := tester.Nodes[0]

	err = tester.TestExchanges(p2ptest.Exchange{
		Label: "Subscribe message",
		Triggers: []p2ptest.Trigger{
			{
				Code: 4,
				Msg: &SubscribeMsg{
					Stream:   stream,
					Priority: Top,
				},
				Peer: node.ID(),
			},
		},
		Expects: []p2ptest.Expect{
			{
				Code: 1,
				Msg: &OfferedHashesMsg{
					Stream: stream,
					HandoverProof: &HandoverProof{
						Handover: &Handover{},
					},
					Hashes: make([]byte, HashSize),
					From:   1,
					To:     0,
				},
				Peer: node.ID(),
			},
		},
	})

	if err != nil {
		t.Fatal(err)
	}

	err = tester.TestExchanges(p2ptest.Exchange{
		Label: "unsubscribe message",
		Triggers: []p2ptest.Trigger{
			{
				Code: 0,
				Msg: &UnsubscribeMsg{
					Stream: stream,
				},
				Peer: node.ID(),
			},
		},
	})

	if err != nil {
		t.Fatal(err)
	}
}

func TestStreamerUpstreamSubscribeErrorMsgExchange(t *testing.T) {
	tester, streamer, _, teardown, err := newStreamerTester(nil)
	if err != nil {
		t.Fatal(err)
	}
	defer teardown()

	streamer.RegisterServerFunc("foo", func(p *Peer, t string, live bool) (Server, error) {
		return newTestServer(t, 0), nil
	})

	stream := NewStream("bar", "", true)

	node := tester.Nodes[0]

	err = tester.TestExchanges(p2ptest.Exchange{
		Label: "Subscribe message",
		Triggers: []p2ptest.Trigger{
			{
				Code: 4,
				Msg: &SubscribeMsg{
					Stream:   stream,
					History:  NewRange(5, 8),
					Priority: Top,
				},
				Peer: node.ID(),
			},
		},
		Expects: []p2ptest.Expect{
			{
				Code: 7,
				Msg: &SubscribeErrorMsg{
					Error: "stream bar not registered",
				},
				Peer: node.ID(),
			},
		},
	})

	if err != nil {
		t.Fatal(err)
	}
}

func TestStreamerUpstreamSubscribeLiveAndHistory(t *testing.T) {
	tester, streamer, _, teardown, err := newStreamerTester(nil)
	if err != nil {
		t.Fatal(err)
	}
	defer teardown()

	stream := NewStream("foo", "", true)

	streamer.RegisterServerFunc("foo", func(p *Peer, t string, live bool) (Server, error) {
		return newTestServer(t, 10), nil
	})

	node := tester.Nodes[0]

	err = tester.TestExchanges(p2ptest.Exchange{
		Label: "Subscribe message",
		Triggers: []p2ptest.Trigger{
			{
				Code: 4,
				Msg: &SubscribeMsg{
					Stream:   stream,
					History:  NewRange(5, 8),
					Priority: Top,
				},
				Peer: node.ID(),
			},
		},
		Expects: []p2ptest.Expect{
			{
				Code: 1,
				Msg: &OfferedHashesMsg{
					Stream: NewStream("foo", "", false),
					HandoverProof: &HandoverProof{
						Handover: &Handover{},
					},
					Hashes: make([]byte, HashSize),
					From:   6,
					To:     9,
				},
				Peer: node.ID(),
			},
			{
				Code: 1,
				Msg: &OfferedHashesMsg{
					Stream: stream,
					HandoverProof: &HandoverProof{
						Handover: &Handover{},
					},
					From:   11,
					To:     0,
					Hashes: make([]byte, HashSize),
				},
				Peer: node.ID(),
			},
		},
	})

	if err != nil {
		t.Fatal(err)
	}
}

func TestStreamerDownstreamCorruptHashesMsgExchange(t *testing.T) {
	tester, streamer, _, teardown, err := newStreamerTester(nil)
	if err != nil {
		t.Fatal(err)
	}
	defer teardown()

	stream := NewStream("foo", "", true)

	var tc *testClient

	streamer.RegisterClientFunc("foo", func(p *Peer, t string, live bool) (Client, error) {
		tc = newTestClient(t)
		return tc, nil
	})

	node := tester.Nodes[0]

	err = streamer.Subscribe(node.ID(), stream, NewRange(5, 8), Top)
	if err != nil {
		t.Fatalf("Expected no error, got %v", err)
	}

	err = tester.TestExchanges(p2ptest.Exchange{
		Label: "Subscribe message",
		Expects: []p2ptest.Expect{
			{
				Code: 4,
				Msg: &SubscribeMsg{
					Stream:   stream,
					History:  NewRange(5, 8),
					Priority: Top,
				},
				Peer: node.ID(),
			},
		},
	},
		p2ptest.Exchange{
			Label: "Corrupt offered hash message",
			Triggers: []p2ptest.Trigger{
				{
					Code: 1,
					Msg: &OfferedHashesMsg{
						HandoverProof: &HandoverProof{
							Handover: &Handover{},
						},
						Hashes: corruptHashes,
						From:   5,
						To:     8,
						Stream: stream,
					},
					Peer: node.ID(),
				},
			},
		})
	if err != nil {
		t.Fatal(err)
	}

	expectedError := errors.New("subprotocol error")
	if err := tester.TestDisconnected(&p2ptest.Disconnect{Peer: node.ID(), Error: expectedError}); err != nil {
		t.Fatal(err)
	}
}

func TestStreamerDownstreamOfferedHashesMsgExchange(t *testing.T) {
	tester, streamer, _, teardown, err := newStreamerTester(nil)
	if err != nil {
		t.Fatal(err)
	}
	defer teardown()

	stream := NewStream("foo", "", true)

	var tc *testClient

	streamer.RegisterClientFunc("foo", func(p *Peer, t string, live bool) (Client, error) {
		tc = newTestClient(t)
		return tc, nil
	})

	node := tester.Nodes[0]

	err = streamer.Subscribe(node.ID(), stream, NewRange(5, 8), Top)
	if err != nil {
		t.Fatalf("Expected no error, got %v", err)
	}

	err = tester.TestExchanges(p2ptest.Exchange{
		Label: "Subscribe message",
		Expects: []p2ptest.Expect{
			{
				Code: 4,
				Msg: &SubscribeMsg{
					Stream:   stream,
					History:  NewRange(5, 8),
					Priority: Top,
				},
				Peer: node.ID(),
			},
		},
	},
		p2ptest.Exchange{
			Label: "WantedHashes message",
			Triggers: []p2ptest.Trigger{
				{
					Code: 1,
					Msg: &OfferedHashesMsg{
						HandoverProof: &HandoverProof{
							Handover: &Handover{},
						},
						Hashes: hashes,
						From:   5,
						To:     8,
						Stream: stream,
					},
					Peer: node.ID(),
				},
			},
			Expects: []p2ptest.Expect{
				{
					Code: 2,
					Msg: &WantedHashesMsg{
						Stream: stream,
						Want:   []byte{5},
						From:   9,
						To:     0,
					},
					Peer: node.ID(),
				},
			},
		})
	if err != nil {
		t.Fatal(err)
	}

	if len(tc.receivedHashes) != 3 {
		t.Fatalf("Expected number of received hashes %v, got %v", 3, len(tc.receivedHashes))
	}

	close(tc.wait0)

	timeout := time.NewTimer(100 * time.Millisecond)
	defer timeout.Stop()

	select {
	case <-tc.batchDone:
		t.Fatal("batch done early")
	case <-timeout.C:
	}

	close(tc.wait2)

	timeout2 := time.NewTimer(10000 * time.Millisecond)
	defer timeout2.Stop()

	select {
	case <-tc.batchDone:
	case <-timeout2.C:
		t.Fatal("timeout waiting batchdone call")
	}

}

func TestStreamerRequestSubscriptionQuitMsgExchange(t *testing.T) {
	tester, streamer, _, teardown, err := newStreamerTester(nil)
	if err != nil {
		t.Fatal(err)
	}
	defer teardown()

	streamer.RegisterServerFunc("foo", func(p *Peer, t string, live bool) (Server, error) {
		return newTestServer(t, 10), nil
	})

	node := tester.Nodes[0]

	stream := NewStream("foo", "", true)
	err = streamer.RequestSubscription(node.ID(), stream, NewRange(5, 8), Top)
	if err != nil {
		t.Fatalf("Expected no error, got %v", err)
	}

	err = tester.TestExchanges(
		p2ptest.Exchange{
			Label: "RequestSubscription message",
			Expects: []p2ptest.Expect{
				{
					Code: 8,
					Msg: &RequestSubscriptionMsg{
						Stream:   stream,
						History:  NewRange(5, 8),
						Priority: Top,
					},
					Peer: node.ID(),
				},
			},
		},
		p2ptest.Exchange{
			Label: "Subscribe message",
			Triggers: []p2ptest.Trigger{
				{
					Code: 4,
					Msg: &SubscribeMsg{
						Stream:   stream,
						History:  NewRange(5, 8),
						Priority: Top,
					},
					Peer: node.ID(),
				},
			},
			Expects: []p2ptest.Expect{
				{
					Code: 1,
					Msg: &OfferedHashesMsg{
						Stream: NewStream("foo", "", false),
						HandoverProof: &HandoverProof{
							Handover: &Handover{},
						},
						Hashes: make([]byte, HashSize),
						From:   6,
						To:     9,
					},
					Peer: node.ID(),
				},
				{
					Code: 1,
					Msg: &OfferedHashesMsg{
						Stream: stream,
						HandoverProof: &HandoverProof{
							Handover: &Handover{},
						},
						From:   11,
						To:     0,
						Hashes: make([]byte, HashSize),
					},
					Peer: node.ID(),
				},
			},
		},
	)
	if err != nil {
		t.Fatal(err)
	}

	err = streamer.Quit(node.ID(), stream)
	if err != nil {
		t.Fatalf("Expected no error, got %v", err)
	}

	err = tester.TestExchanges(p2ptest.Exchange{
		Label: "Quit message",
		Expects: []p2ptest.Expect{
			{
				Code: 9,
				Msg: &QuitMsg{
					Stream: stream,
				},
				Peer: node.ID(),
			},
		},
	})

	if err != nil {
		t.Fatal(err)
	}

	historyStream := getHistoryStream(stream)

	err = streamer.Quit(node.ID(), historyStream)
	if err != nil {
		t.Fatalf("Expected no error, got %v", err)
	}

	err = tester.TestExchanges(p2ptest.Exchange{
		Label: "Quit message",
		Expects: []p2ptest.Expect{
			{
				Code: 9,
				Msg: &QuitMsg{
					Stream: historyStream,
				},
				Peer: node.ID(),
			},
		},
	})

	if err != nil {
		t.Fatal(err)
	}
}

// TestMaxPeerServersWithUnsubscribe creates a registry with a limited
// number of stream servers, and performs a test with subscriptions and
// unsubscriptions, checking if unsubscriptions will remove streams,
// leaving place for new streams.
func TestMaxPeerServersWithUnsubscribe(t *testing.T) {
	var maxPeerServers = 6
	tester, streamer, _, teardown, err := newStreamerTester(&RegistryOptions{
		Syncing:        SyncingDisabled,
		MaxPeerServers: maxPeerServers,
	})
	if err != nil {
		t.Fatal(err)
	}
	defer teardown()

	streamer.RegisterServerFunc("foo", func(p *Peer, t string, live bool) (Server, error) {
		return newTestServer(t, 0), nil
	})

	node := tester.Nodes[0]

	for i := 0; i < maxPeerServers+10; i++ {
		stream := NewStream("foo", strconv.Itoa(i), true)

		err = tester.TestExchanges(p2ptest.Exchange{
			Label: "Subscribe message",
			Triggers: []p2ptest.Trigger{
				{
					Code: 4,
					Msg: &SubscribeMsg{
						Stream:   stream,
						Priority: Top,
					},
					Peer: node.ID(),
				},
			},
			Expects: []p2ptest.Expect{
				{
					Code: 1,
					Msg: &OfferedHashesMsg{
						Stream: stream,
						HandoverProof: &HandoverProof{
							Handover: &Handover{},
						},
						Hashes: make([]byte, HashSize),
						From:   1,
						To:     0,
					},
					Peer: node.ID(),
				},
			},
		})

		if err != nil {
			t.Fatal(err)
		}

		err = tester.TestExchanges(p2ptest.Exchange{
			Label: "unsubscribe message",
			Triggers: []p2ptest.Trigger{
				{
					Code: 0,
					Msg: &UnsubscribeMsg{
						Stream: stream,
					},
					Peer: node.ID(),
				},
			},
		})

		if err != nil {
			t.Fatal(err)
		}
	}
}

// TestMaxPeerServersWithoutUnsubscribe creates a registry with a limited
// number of stream servers, and performs subscriptions to detect subscriptions
// error message exchange.
func TestMaxPeerServersWithoutUnsubscribe(t *testing.T) {
	var maxPeerServers = 6
	tester, streamer, _, teardown, err := newStreamerTester(&RegistryOptions{
		MaxPeerServers: maxPeerServers,
	})
	if err != nil {
		t.Fatal(err)
	}
	defer teardown()

	streamer.RegisterServerFunc("foo", func(p *Peer, t string, live bool) (Server, error) {
		return newTestServer(t, 0), nil
	})

	node := tester.Nodes[0]

	for i := 0; i < maxPeerServers+10; i++ {
		stream := NewStream("foo", strconv.Itoa(i), true)

		if i >= maxPeerServers {
			err = tester.TestExchanges(p2ptest.Exchange{
				Label: "Subscribe message",
				Triggers: []p2ptest.Trigger{
					{
						Code: 4,
						Msg: &SubscribeMsg{
							Stream:   stream,
							Priority: Top,
						},
						Peer: node.ID(),
					},
				},
				Expects: []p2ptest.Expect{
					{
						Code: 7,
						Msg: &SubscribeErrorMsg{
							Error: ErrMaxPeerServers.Error(),
						},
						Peer: node.ID(),
					},
				},
			})

			if err != nil {
				t.Fatal(err)
			}
			continue
		}

		err = tester.TestExchanges(p2ptest.Exchange{
			Label: "Subscribe message",
			Triggers: []p2ptest.Trigger{
				{
					Code: 4,
					Msg: &SubscribeMsg{
						Stream:   stream,
						Priority: Top,
					},
					Peer: node.ID(),
				},
			},
			Expects: []p2ptest.Expect{
				{
					Code: 1,
					Msg: &OfferedHashesMsg{
						Stream: stream,
						HandoverProof: &HandoverProof{
							Handover: &Handover{},
						},
						Hashes: make([]byte, HashSize),
						From:   1,
						To:     0,
					},
					Peer: node.ID(),
				},
			},
		})

		if err != nil {
			t.Fatal(err)
		}
	}
}

//TestHasPriceImplementation is to check that the Registry has a
//`Price` interface implementation
func TestHasPriceImplementation(t *testing.T) {
	_, r, _, teardown, err := newStreamerTester(&RegistryOptions{
		Syncing: SyncingDisabled,
	})
	if err != nil {
		t.Fatal(err)
	}
	defer teardown()

	if r.prices == nil {
		t.Fatal("No prices implementation available for the stream protocol")
	}

	pricesInstance, ok := r.prices.(*StreamerPrices)
	if !ok {
		t.Fatal("`Registry` does not have the expected Prices instance")
	}
	price := pricesInstance.Price(&ChunkDeliveryMsgRetrieval{})
	if price == nil || price.Value == 0 || price.Value != pricesInstance.getChunkDeliveryMsgRetrievalPrice() {
		t.Fatal("No prices set for chunk delivery msg")
	}

	price = pricesInstance.Price(&RetrieveRequestMsg{})
	if price == nil || price.Value == 0 || price.Value != pricesInstance.getRetrieveRequestMsgPrice() {
		t.Fatal("No prices set for chunk delivery msg")
	}
}

// TestGetServerSubscriptions is a unit test for the api.GetPeerServerSubscriptions() function
func TestGetServerSubscriptions(t *testing.T) {
	// create an amount of dummy peers
	testPeerCount := 8
	// every peer will have this amount of dummy servers
	testServerCount := 4
	// the peerMap which will store this data for the registry
	peerMap := make(map[enode.ID]*Peer)
	// create the registry
	r := &Registry{}
	api := NewAPI(r)
	// call once, at this point should be empty
	regs := api.GetPeerServerSubscriptions()
	if len(regs) != 0 {
		t.Fatal("Expected subscription count to be 0, but it is not")
	}

	// now create a number of dummy servers for each node
	for i := 0; i < testPeerCount; i++ {
		addr := network.RandomAddr()
		id := addr.ID()
		p := &Peer{}
		p.servers = make(map[Stream]*server)
		for k := 0; k < testServerCount; k++ {
			s := Stream{
				Name: strconv.Itoa(k),
				Key:  "",
				Live: false,
			}
			p.servers[s] = &server{}
		}
		peerMap[id] = p
	}
	r.peers = peerMap

	// call the subscriptions again
	regs = api.GetPeerServerSubscriptions()
	// count how many (fake) subscriptions there are
	cnt := 0
	for _, reg := range regs {
		for range reg {
			cnt++
		}
	}
	// check expected value
	expectedCount := testPeerCount * testServerCount
	if cnt != expectedCount {
		t.Fatalf("Expected %d subscriptions, but got %d", expectedCount, cnt)
	}
}

/*
TestGetServerSubscriptionsRPC sets up a simulation network of `nodeCount` nodes,
starts the simulation, waits for SyncUpdateDelay in order to kick off
stream registration, then tests that there are subscriptions.
*/
func TestGetServerSubscriptionsRPC(t *testing.T) {

	if testutil.RaceEnabled && os.Getenv("TRAVIS") == "true" {
		t.Skip("flaky with -race on Travis")
		// Note: related ticket https://github.com/ethersphere/go-ethereum/issues/1234
	}

	// arbitrarily set to 4
	nodeCount := 4
	// set the syncUpdateDelay for sync registrations to start
	syncUpdateDelay := 200 * time.Millisecond
	// run with more nodes if `longrunning` flag is set
	if *longrunning {
		nodeCount = 64
		syncUpdateDelay = 10 * time.Second
	}
	// holds the msg code for SubscribeMsg
	var subscribeMsgCode uint64
	var ok bool
	var expectedMsgCount counter

	// this channel signalizes that the expected amount of subscriptiosn is done
	allSubscriptionsDone := make(chan struct{})
	// after the test, we need to reset the subscriptionFunc to the default
	defer func() { subscriptionFunc = doRequestSubscription }()

	// we use this subscriptionFunc for this test: just increases count and calls the actual subscription
	subscriptionFunc = func(r *Registry, id enode.ID, bin uint8) error {
		// syncing starts after syncUpdateDelay and loops after that Duration; we only want to count at the first iteration
		// in the first iteration, subs will be empty (no existing subscriptions), thus we can use this check
		// this avoids flakyness
		expectedMsgCount.inc()
		doRequestSubscription(r, id, bin)
		return nil
	}
	// create a standard sim
	sim := simulation.New(map[string]simulation.ServiceFunc{
		"streamer": func(ctx *adapters.ServiceContext, bucket *sync.Map) (s node.Service, cleanup func(), err error) {
			addr, netStore, delivery, clean, err := newNetStoreAndDeliveryWithRequestFunc(ctx, bucket, dummyRequestFromPeers)
			if err != nil {
				return nil, nil, err
			}

			// configure so that sync registrations actually happen
			r := NewRegistry(addr.ID(), delivery, netStore, state.NewInmemoryStore(), &RegistryOptions{
				Syncing:         SyncingAutoSubscribe, //enable sync registrations
				SyncUpdateDelay: syncUpdateDelay,
			}, nil)

			// get the SubscribeMsg code
			subscribeMsgCode, ok = r.GetSpec().GetCode(SubscribeMsg{})
			if !ok {
				t.Fatal("Message code for SubscribeMsg not found")
			}

			cleanup = func() {
				r.Close()
				clean()
			}

			return r, cleanup, nil
		},
	})
	defer sim.Close()

	ctx, cancelSimRun := context.WithTimeout(context.Background(), 3*time.Minute)
	defer cancelSimRun()

	// setup the filter for SubscribeMsg
	msgs := sim.PeerEvents(
		context.Background(),
		sim.UpNodeIDs(),
		simulation.NewPeerEventsFilter().ReceivedMessages().Protocol("stream").MsgCode(subscribeMsgCode),
	)

	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Minute)
	defer cancel()
	filename := fmt.Sprintf("testing/snapshot_%d.json", nodeCount)
	if err := sim.UploadSnapshot(ctx, filename); err != nil {
		t.Fatal(err)
	}

	// strategy: listen to all SubscribeMsg events; after every event we wait
	// if after `waitDuration` no more messages are being received, we assume the
	// subscription phase has terminated!

	// the loop in this go routine will either wait for new message events
	// or times out after 1 second, which signals that we are not receiving
	// any new subscriptions any more
	go func() {
		//for long running sims, waiting 1 sec will not be enough
		waitDuration := 1 * time.Second
		if *longrunning {
			waitDuration = 3 * time.Second
		}
		for {
			select {
			case <-ctx.Done():
				return
			case m := <-msgs: // just reset the loop
				if m.Error != nil {
					log.Error("stream message", "err", m.Error)
					continue
				}
				log.Trace("stream message", "node", m.NodeID, "peer", m.PeerID)
			case <-time.After(waitDuration):
				// one second passed, don't assume more subscriptions
				allSubscriptionsDone <- struct{}{}
				log.Info("All subscriptions received")
				return

			}
		}
	}()

	//run the simulation
	result := sim.Run(ctx, func(ctx context.Context, sim *simulation.Simulation) error {
		log.Info("Simulation running")
		nodes := sim.Net.Nodes

		//wait until all subscriptions are done
		select {
		case <-allSubscriptionsDone:
		case <-ctx.Done():
			return errors.New("Context timed out")
		}

		log.Debug("Expected message count: ", "expectedMsgCount", expectedMsgCount.count())
		//now iterate again, this time we call each node via RPC to get its subscriptions
		realCount := 0
		for _, node := range nodes {
			//create rpc client
			client, err := node.Client()
			if err != nil {
				return fmt.Errorf("create node 1 rpc client fail: %v", err)
			}

			//ask it for subscriptions
			pstreams := make(map[string][]string)
			err = client.Call(&pstreams, "stream_getPeerServerSubscriptions")
			if err != nil {
				return fmt.Errorf("client call stream_getPeerSubscriptions: %v", err)
			}
			//length of the subscriptions can not be smaller than number of peers
			log.Debug("node subscriptions", "node", node.String())
			for p, ps := range pstreams {
				log.Debug("... with", "peer", p)
				for _, s := range ps {
					log.Debug(".......", "stream", s)
					// each node also has subscriptions to RETRIEVE_REQUEST streams,
					// we need to ignore those, we are only counting SYNC streams
					if !strings.HasPrefix(s, "RETRIEVE_REQUEST") {
						realCount++
					}
				}
			}
			log.Debug("All node streams counted", "realCount", realCount)
		}
		emc := expectedMsgCount.count()
		// after a subscription request, internally a live AND a history stream will be subscribed,
		// thus the real count should be half of the actual request subscriptions sent
		if realCount/2 != emc {
			return fmt.Errorf("Real subscriptions and expected amount don't match; real: %d, expected: %d", realCount/2, emc)
		}
		return nil
	})
	if result.Error != nil {
		t.Fatal(result.Error)
	}
}

// counter is used to concurrently increment
// and read an integer value.
type counter struct {
	v  int
	mu sync.RWMutex
}

// Increment the counter.
func (c *counter) inc() {
	c.mu.Lock()
	defer c.mu.Unlock()

	c.v++
}

// Read the counter value.
func (c *counter) count() int {
	c.mu.RLock()
	defer c.mu.RUnlock()

	return c.v
}