package whisper

import (
	"context"
	"encoding/hex"
	"encoding/json"
	"fmt"
	"os"
	"path/filepath"
	"sort"
	"strconv"
	"strings"
	"testing"
	"time"

	"github.com/status-im/status-go/services/shhext"

	"github.com/stretchr/testify/suite"
	"golang.org/x/crypto/sha3"

	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/common/hexutil"
	"github.com/ethereum/go-ethereum/crypto"
	"github.com/ethereum/go-ethereum/p2p"

	"github.com/status-im/status-go/api"
	"github.com/status-im/status-go/mailserver"
	"github.com/status-im/status-go/params"
	"github.com/status-im/status-go/rpc"
	"github.com/status-im/status-go/t/helpers"
	"github.com/status-im/status-go/t/utils"
	"github.com/status-im/status-go/whisper/v6"
)

const mailboxPassword = "status-offline-inbox"

type WhisperMailboxSuite struct {
	suite.Suite
}

func TestWhisperMailboxTestSuite(t *testing.T) {
	utils.Init()
	suite.Run(t, new(WhisperMailboxSuite))
}

func (s *WhisperMailboxSuite) TestRequestMessageFromMailboxAsync() {
	var err error
	// Start mailbox and status node.
	mailboxBackend, stop := s.startMailboxBackend("")
	defer stop()
	s.Require().True(mailboxBackend.IsNodeRunning())
	mailboxNode := mailboxBackend.StatusNode().GethNode()
	mailboxEnode := mailboxNode.Server().NodeInfo().Enode

	sender, stop := s.startBackend("sender")
	defer stop()
	s.Require().True(sender.IsNodeRunning())
	node := sender.StatusNode().GethNode()

	s.Require().NotEqual(mailboxEnode, node.Server().NodeInfo().Enode)

	errCh := helpers.WaitForPeerAsync(sender.StatusNode().Server(), mailboxEnode, p2p.PeerEventTypeAdd, time.Second)
	s.Require().NoError(sender.StatusNode().AddPeer(mailboxEnode))
	s.Require().NoError(<-errCh)

	senderWhisperService, err := sender.StatusNode().WhisperService()
	s.Require().NoError(err)

	// This sleep still is required because there is still a race condition
	// when adding a peer to p2p.Server and to Whisper service.
	// It may happen that the event about the added peer
	// was emitted by p2p.Server but Whisper service is not aware of it yet.
	time.Sleep(time.Second)

	// Mark mailbox node trusted.
	err = senderWhisperService.AllowP2PMessagesFromPeer(mailboxNode.Server().Self().ID().Bytes())
	s.Require().NoError(err)

	// Generate mailbox symkey.
	password := mailboxPassword
	MailServerKeyID, err := senderWhisperService.AddSymKeyFromPassword(password)
	s.Require().NoError(err)

	rpcClient := sender.StatusNode().RPCPrivateClient()
	s.Require().NotNil(rpcClient)

	mailboxWhisperService, err := mailboxBackend.StatusNode().WhisperService()
	s.Require().NoError(err)
	s.Require().NotNil(mailboxWhisperService)

	// watch envelopes to be archived on mailserver
	envelopeArchivedWatcher := make(chan whisper.EnvelopeEvent, 1024)
	sub := mailboxWhisperService.SubscribeEnvelopeEvents(envelopeArchivedWatcher)
	defer sub.Unsubscribe()

	// watch envelopes to be available for filters in the client
	envelopeAvailableWatcher := make(chan whisper.EnvelopeEvent, 1024)
	sub = senderWhisperService.SubscribeEnvelopeEvents(envelopeAvailableWatcher)
	defer sub.Unsubscribe()

	// watch mailserver responses in the client
	mailServerResponseWatcher := make(chan whisper.EnvelopeEvent, 1024)
	sub = senderWhisperService.SubscribeEnvelopeEvents(mailServerResponseWatcher)
	defer sub.Unsubscribe()

	// Create topic.
	topic := whisper.BytesToTopic([]byte("topic name"))

	// Add key pair to whisper.
	keyID, err := senderWhisperService.NewKeyPair()
	s.Require().NoError(err)
	key, err := senderWhisperService.GetPrivateKey(keyID)
	s.Require().NoError(err)
	pubkey := hexutil.Bytes(crypto.FromECDSAPub(&key.PublicKey))

	// Create message filter.
	messageFilterID := s.createPrivateChatMessageFilter(rpcClient, keyID, topic.String())

	// There are no messages at filter.
	messages := s.getMessagesByMessageFilterID(rpcClient, messageFilterID)
	s.Require().Empty(messages)

	// Post message matching with filter (key and topic).
	messageHash := s.postMessageToPrivate(rpcClient, pubkey.String(), topic.String(), hexutil.Encode([]byte("Hello world!")))

	// Get message to make sure that it will come from the mailbox later.
	s.waitForEnvelopeEvents(envelopeAvailableWatcher, []string{messageHash}, whisper.EventEnvelopeAvailable)
	messages = s.getMessagesByMessageFilterID(rpcClient, messageFilterID)
	s.Require().Equal(1, len(messages))

	// Act.

	// wait for mailserver to archive all the envelopes
	s.waitForEnvelopeEvents(envelopeArchivedWatcher, []string{messageHash}, whisper.EventMailServerEnvelopeArchived)

	// Request messages (including the previous one, expired) from mailbox.
	requestID := s.requestHistoricMessagesFromLast12Hours(senderWhisperService, rpcClient, mailboxNode.Server().Self().URLv4(), MailServerKeyID, topic.String(), 0, "")

	// wait for mail server response
	resp := s.waitForMailServerResponse(mailServerResponseWatcher, requestID)
	s.Require().Equal(messageHash, resp.LastEnvelopeHash.String())
	s.Require().Empty(resp.Cursor)

	// wait for last envelope sent by the mailserver to be available for filters
	s.waitForEnvelopeEvents(envelopeAvailableWatcher, []string{resp.LastEnvelopeHash.String()}, whisper.EventEnvelopeAvailable)

	// And we receive message, it comes from mailbox.
	messages = s.getMessagesByMessageFilterID(rpcClient, messageFilterID)
	s.Require().Equal(1, len(messages))

	// Check that there are no messages.
	messages = s.getMessagesByMessageFilterID(rpcClient, messageFilterID)
	s.Require().Empty(messages)
}

func (s *WhisperMailboxSuite) TestRequestMessagesInGroupChat() {
	var err error

	// Start mailbox, alice, bob, charlie node.
	mailboxBackend, stop := s.startMailboxBackend("")
	defer stop()

	aliceBackend, stop := s.startBackend("alice")
	defer stop()

	bobBackend, stop := s.startBackend("bob")
	defer stop()

	charlieBackend, stop := s.startBackend("charlie")
	defer stop()

	// Add mailbox to static peers.
	s.Require().True(mailboxBackend.IsNodeRunning())
	mailboxNode := mailboxBackend.StatusNode().GethNode()
	mailboxEnode := mailboxNode.Server().NodeInfo().Enode

	aliceErrCh := helpers.WaitForPeerAsync(aliceBackend.StatusNode().Server(), mailboxEnode, p2p.PeerEventTypeAdd, 5*time.Second)
	bobErrCh := helpers.WaitForPeerAsync(bobBackend.StatusNode().Server(), mailboxEnode, p2p.PeerEventTypeAdd, 5*time.Second)
	charlieErrCh := helpers.WaitForPeerAsync(charlieBackend.StatusNode().Server(), mailboxEnode, p2p.PeerEventTypeAdd, 5*time.Second)

	s.Require().NoError(aliceBackend.StatusNode().AddPeer(mailboxEnode))
	s.Require().NoError(bobBackend.StatusNode().AddPeer(mailboxEnode))
	s.Require().NoError(charlieBackend.StatusNode().AddPeer(mailboxEnode))

	s.Require().NoError(<-aliceErrCh)
	s.Require().NoError(<-bobErrCh)
	s.Require().NoError(<-charlieErrCh)

	// Get whisper service.
	mailboxWhisperService, err := mailboxBackend.StatusNode().WhisperService()
	s.Require().NoError(err)
	aliceWhisperService, err := aliceBackend.StatusNode().WhisperService()
	s.Require().NoError(err)
	bobWhisperService, err := bobBackend.StatusNode().WhisperService()
	s.Require().NoError(err)
	charlieWhisperService, err := charlieBackend.StatusNode().WhisperService()
	s.Require().NoError(err)
	// Get rpc client.
	aliceRPCClient := aliceBackend.StatusNode().RPCPrivateClient()
	bobRPCClient := bobBackend.StatusNode().RPCPrivateClient()
	charlieRPCClient := charlieBackend.StatusNode().RPCPrivateClient()

	// watchers
	envelopeArchivedWatcher := make(chan whisper.EnvelopeEvent, 1024)
	sub := mailboxWhisperService.SubscribeEnvelopeEvents(envelopeArchivedWatcher)
	defer sub.Unsubscribe()

	bobEnvelopeAvailableWatcher := make(chan whisper.EnvelopeEvent, 1024)
	sub = bobWhisperService.SubscribeEnvelopeEvents(bobEnvelopeAvailableWatcher)
	defer sub.Unsubscribe()

	charlieEnvelopeAvailableWatcher := make(chan whisper.EnvelopeEvent, 1024)
	sub = charlieWhisperService.SubscribeEnvelopeEvents(charlieEnvelopeAvailableWatcher)
	defer sub.Unsubscribe()

	// Bob and charlie add the mailserver key.
	password := mailboxPassword
	bobMailServerKeyID, err := bobWhisperService.AddSymKeyFromPassword(password)
	s.Require().NoError(err)
	charlieMailServerKeyID, err := charlieWhisperService.AddSymKeyFromPassword(password)
	s.Require().NoError(err)

	// Generate a group chat symkey and topic.
	groupChatKeyID, err := aliceWhisperService.GenerateSymKey()
	s.Require().NoError(err)
	groupChatKey, err := aliceWhisperService.GetSymKey(groupChatKeyID)
	s.Require().NoError(err)
	// Generate a group chat topic.
	groupChatTopic := whisper.BytesToTopic([]byte("groupChatTopic"))
	// sender must be subscribed to message topic it sends
	s.NotNil(s.createGroupChatMessageFilter(aliceRPCClient, groupChatKeyID, groupChatTopic.String()))
	groupChatPayload := newGroupChatParams(groupChatKey, groupChatTopic)
	payloadStr, err := groupChatPayload.Encode()
	s.Require().NoError(err)

	// Add Bob and Charlie's key pairs to receive the symmetric key for the group chat from Alice.
	bobKeyID, err := bobWhisperService.NewKeyPair()
	s.Require().NoError(err)
	bobKey, err := bobWhisperService.GetPrivateKey(bobKeyID)
	s.Require().NoError(err)
	bobPubkey := hexutil.Bytes(crypto.FromECDSAPub(&bobKey.PublicKey))
	bobAliceKeySendTopic := whisper.BytesToTopic([]byte("bobAliceKeySendTopic "))

	charlieKeyID, err := charlieWhisperService.NewKeyPair()
	s.Require().NoError(err)
	charlieKey, err := charlieWhisperService.GetPrivateKey(charlieKeyID)
	s.Require().NoError(err)
	charliePubkey := hexutil.Bytes(crypto.FromECDSAPub(&charlieKey.PublicKey))
	charlieAliceKeySendTopic := whisper.BytesToTopic([]byte("charlieAliceKeySendTopic "))

	// Alice must add peers topics into her own bloom filter.
	aliceKeyID, err := aliceWhisperService.NewKeyPair()
	s.Require().NoError(err)
	s.createPrivateChatMessageFilter(aliceRPCClient, aliceKeyID, bobAliceKeySendTopic.String())
	s.createPrivateChatMessageFilter(aliceRPCClient, aliceKeyID, charlieAliceKeySendTopic.String())

	// Bob and charlie create message filter.
	bobMessageFilterID := s.createPrivateChatMessageFilter(bobRPCClient, bobKeyID, bobAliceKeySendTopic.String())
	charlieMessageFilterID := s.createPrivateChatMessageFilter(charlieRPCClient, charlieKeyID, charlieAliceKeySendTopic.String())

	// Alice send message with symkey and topic to Bob and Charlie.
	aliceToBobMessageHash := s.postMessageToPrivate(aliceRPCClient, bobPubkey.String(), bobAliceKeySendTopic.String(), payloadStr)
	aliceToCharlieMessageHash := s.postMessageToPrivate(aliceRPCClient, charliePubkey.String(), charlieAliceKeySendTopic.String(), payloadStr)

	// Bob receive group chat data and add it to his node.
	// Bob get group chat details.
	s.waitForEnvelopeEvents(bobEnvelopeAvailableWatcher, []string{aliceToBobMessageHash}, whisper.EventEnvelopeAvailable)
	messages := s.getMessagesByMessageFilterID(bobRPCClient, bobMessageFilterID)
	s.Require().Equal(1, len(messages))
	bobGroupChatData := groupChatParams{}
	err = bobGroupChatData.Decode(messages[0]["payload"].(string))
	s.Require().NoError(err)
	s.EqualValues(groupChatPayload, bobGroupChatData)

	// Bob add symkey to his node.
	bobGroupChatSymkeyID := s.addSymKey(bobRPCClient, bobGroupChatData.Key)
	s.Require().NotEmpty(bobGroupChatSymkeyID)

	// Bob create message filter to node by group chat topic.
	bobGroupChatMessageFilterID := s.createGroupChatMessageFilter(bobRPCClient, bobGroupChatSymkeyID, bobGroupChatData.Topic)

	// Charlie receive group chat data and add it to his node.
	// Charlie get group chat details.
	s.waitForEnvelopeEvents(charlieEnvelopeAvailableWatcher, []string{aliceToCharlieMessageHash}, whisper.EventEnvelopeAvailable)
	messages = s.getMessagesByMessageFilterID(charlieRPCClient, charlieMessageFilterID)
	s.Require().Equal(1, len(messages))
	charlieGroupChatData := groupChatParams{}
	err = charlieGroupChatData.Decode(messages[0]["payload"].(string))
	s.Require().NoError(err)
	s.EqualValues(groupChatPayload, charlieGroupChatData)

	// Charlie add symkey to his node.
	charlieGroupChatSymkeyID := s.addSymKey(charlieRPCClient, charlieGroupChatData.Key)
	s.Require().NotEmpty(charlieGroupChatSymkeyID)

	// Charlie create message filter to node by group chat topic.
	charlieGroupChatMessageFilterID := s.createGroupChatMessageFilter(charlieRPCClient, charlieGroupChatSymkeyID, charlieGroupChatData.Topic)

	// Alice send message to group chat.
	helloWorldMessage := hexutil.Encode([]byte("Hello world!"))
	groupChatMessageHash := s.postMessageToGroup(aliceRPCClient, groupChatKeyID, groupChatTopic.String(), helloWorldMessage)

	// Bob receive group chat message.
	s.waitForEnvelopeEvents(bobEnvelopeAvailableWatcher, []string{groupChatMessageHash}, whisper.EventEnvelopeAvailable)
	messages = s.getMessagesByMessageFilterID(bobRPCClient, bobGroupChatMessageFilterID)
	s.Require().Equal(1, len(messages))
	s.Require().Equal(helloWorldMessage, messages[0]["payload"].(string))

	// Charlie receive group chat message.
	s.waitForEnvelopeEvents(charlieEnvelopeAvailableWatcher, []string{groupChatMessageHash}, whisper.EventEnvelopeAvailable)
	messages = s.getMessagesByMessageFilterID(charlieRPCClient, charlieGroupChatMessageFilterID)
	s.Require().Equal(1, len(messages))
	s.Require().Equal(helloWorldMessage, messages[0]["payload"].(string))

	// Check that we don't receive messages each one time.
	messages = s.getMessagesByMessageFilterID(bobRPCClient, bobGroupChatMessageFilterID)
	s.Require().Empty(messages)
	messages = s.getMessagesByMessageFilterID(charlieRPCClient, charlieGroupChatMessageFilterID)
	s.Require().Empty(messages)

	// be sure that message has been archived
	s.waitForEnvelopeEvents(envelopeArchivedWatcher, []string{groupChatMessageHash}, whisper.EventMailServerEnvelopeArchived)

	// Request each one messages from mailbox using enode.
	s.requestHistoricMessagesFromLast12Hours(bobWhisperService, bobRPCClient, mailboxEnode, bobMailServerKeyID, groupChatTopic.String(), 0, "")
	s.requestHistoricMessagesFromLast12Hours(charlieWhisperService, charlieRPCClient, mailboxEnode, charlieMailServerKeyID, groupChatTopic.String(), 0, "")

	// Bob receive p2p message from group chat filter.
	s.waitForEnvelopeEvents(bobEnvelopeAvailableWatcher, []string{groupChatMessageHash}, whisper.EventEnvelopeAvailable)
	messages = s.getMessagesByMessageFilterID(bobRPCClient, bobGroupChatMessageFilterID)
	s.Require().Equal(1, len(messages))
	s.Require().Equal(helloWorldMessage, messages[0]["payload"].(string))

	// Charlie receive p2p message from group chat filter.
	s.waitForEnvelopeEvents(charlieEnvelopeAvailableWatcher, []string{groupChatMessageHash}, whisper.EventEnvelopeAvailable)
	messages = s.getMessagesByMessageFilterID(charlieRPCClient, charlieGroupChatMessageFilterID)
	s.Require().Equal(1, len(messages))
	s.Require().Equal(helloWorldMessage, messages[0]["payload"].(string))
}

func (s *WhisperMailboxSuite) TestRequestMessagesWithPagination() {
	// Start mailbox
	mailbox, stop := s.startMailboxBackend("")
	defer stop()
	s.Require().True(mailbox.IsNodeRunning())
	mailboxEnode := mailbox.StatusNode().GethNode().Server().NodeInfo().Enode

	// Start client
	client, stop := s.startBackend("client")
	defer stop()
	s.Require().True(client.IsNodeRunning())
	clientRPCClient := client.StatusNode().RPCPrivateClient()

	// Add mailbox to client's peers
	errCh := helpers.WaitForPeerAsync(client.StatusNode().Server(), mailboxEnode, p2p.PeerEventTypeAdd, 5*time.Second)
	s.Require().NoError(client.StatusNode().AddPeer(mailboxEnode))
	s.Require().NoError(<-errCh)

	// Whisper services
	mailboxWhisperService, err := mailbox.StatusNode().WhisperService()
	s.Require().NoError(err)
	clientWhisperService, err := client.StatusNode().WhisperService()
	s.Require().NoError(err)
	// mailserver sym key
	mailServerKeyID, err := clientWhisperService.AddSymKeyFromPassword(mailboxPassword)
	s.Require().NoError(err)

	// public chat
	var (
		keyID    string
		topic    whisper.TopicType
		filterID string
	)
	publicChatName := "test public chat"
	keyID, topic, filterID = s.joinPublicChat(clientWhisperService, clientRPCClient, publicChatName)

	// envelopes to be sent
	envelopesCount := 5
	sentEnvelopesHashes := make([]string, 0)

	// watch envelopes to be archived on mailserver
	envelopeArchivedWatcher := make(chan whisper.EnvelopeEvent, 1024)
	sub := mailboxWhisperService.SubscribeEnvelopeEvents(envelopeArchivedWatcher)
	defer sub.Unsubscribe()

	// watch envelopes to be available for filters in the client
	envelopeAvailableWatcher := make(chan whisper.EnvelopeEvent, 1024)
	sub = clientWhisperService.SubscribeEnvelopeEvents(envelopeAvailableWatcher)
	defer sub.Unsubscribe()

	// watch mailserver responses in the client
	mailServerResponseWatcher := make(chan whisper.EnvelopeEvent, 1024)
	sub = clientWhisperService.SubscribeEnvelopeEvents(mailServerResponseWatcher)
	defer sub.Unsubscribe()

	// send envelopes
	for i := 0; i < envelopesCount; i++ {
		hash := s.postMessageToGroup(clientRPCClient, keyID, topic.String(), "")
		sentEnvelopesHashes = append(sentEnvelopesHashes, hash)
	}

	// get messages from filter before requesting them to mailserver
	lastEnvelopeHash := sentEnvelopesHashes[len(sentEnvelopesHashes)-1]
	s.waitForEnvelopeEvents(envelopeAvailableWatcher, []string{lastEnvelopeHash}, whisper.EventEnvelopeAvailable)
	messages := s.getMessagesByMessageFilterID(clientRPCClient, filterID)
	s.Equal(envelopesCount, len(messages))

	messages = s.getMessagesByMessageFilterID(clientRPCClient, filterID)
	s.Equal(0, len(messages))

	limit := 3

	getMessages := func() []string {
		envelopes := s.getMessagesByMessageFilterID(clientRPCClient, filterID)
		hashes := make([]string, 0)
		for _, e := range envelopes {
			hashes = append(hashes, e["hash"].(string))
		}

		return hashes
	}

	requestMessages := func(cursor string) common.Hash {
		return s.requestHistoricMessagesFromLast12Hours(clientWhisperService, clientRPCClient, mailboxEnode, mailServerKeyID, topic.String(), limit, cursor)
	}

	// wait for mailserver to archive all the envelopes
	s.waitForEnvelopeEvents(envelopeArchivedWatcher, sentEnvelopesHashes, whisper.EventMailServerEnvelopeArchived)

	// first page
	// send request
	requestID := requestMessages("")
	// wait for mail server response
	resp := s.waitForMailServerResponse(mailServerResponseWatcher, requestID)
	s.NotEmpty(resp.LastEnvelopeHash)
	s.NotEmpty(resp.Cursor)
	// wait for last envelope sent by the mailserver to be available for filters
	s.waitForEnvelopeEvents(envelopeAvailableWatcher, []string{resp.LastEnvelopeHash.String()}, whisper.EventEnvelopeAvailable)
	// get messages
	firstPageHashes := getMessages()
	s.Equal(3, len(firstPageHashes))

	// second page
	// send request
	requestID = requestMessages(fmt.Sprintf("%x", resp.Cursor))
	// wait for mail server response
	resp = s.waitForMailServerResponse(mailServerResponseWatcher, requestID)
	s.NotEmpty(resp.LastEnvelopeHash)
	// all messages have been sent, no more pages available
	s.Empty(resp.Cursor)
	// wait for last envelope sent by the mailserver to be available for filters
	s.waitForEnvelopeEvents(envelopeAvailableWatcher, []string{resp.LastEnvelopeHash.String()}, whisper.EventEnvelopeAvailable)
	// get messages
	secondPageHashes := getMessages()
	s.Equal(2, len(secondPageHashes))

	allReceivedHashes := append(firstPageHashes, secondPageHashes...)
	s.Equal(envelopesCount, len(allReceivedHashes))

	// check that all the envelopes have been received
	sort.Strings(sentEnvelopesHashes)
	sort.Strings(allReceivedHashes)
	s.Equal(sentEnvelopesHashes, allReceivedHashes)
}

// TestSyncBetweenTwoMailServers tests syncing state between two mail servers
// using `shhext_requestMessages`.
func (s *WhisperMailboxSuite) TestSyncBetweenTwoMailServers() {
	var (
		chatName = "some-public-chat"
	)

	// Start mailbox but with mail server disabled.
	// MailServer will be registered below manually.
	mailbox, stop := s.startMailboxBackendWithCallback("", func(c *params.NodeConfig) {
		c.WhisperConfig.EnableMailServer = false
	})
	defer stop()
	s.Require().True(mailbox.IsNodeRunning())
	mailboxEnode := mailbox.StatusNode().GethNode().Server().NodeInfo().Enode

	// Whisper services
	mailboxWhisperService, err := mailbox.StatusNode().WhisperService()
	s.Require().NoError(err)

	// symmetric key for public chats
	symKeyID, err := mailboxWhisperService.AddSymKeyFromPassword(chatName)
	s.Require().NoError(err)
	publicChatSymKey, err := mailboxWhisperService.GetSymKey(symKeyID)
	s.Require().NoError(err)

	var mailServer mailserver.WhisperMailServer
	err = mailServer.Init(mailboxWhisperService, &mailbox.StatusNode().Config().WhisperConfig)
	s.Require().NoError(err)
	mailboxWhisperService.RegisterMailServer(&mailServer)

	// envelopes to archive
	envelopesCount := 5
	topic := s.createPublicChatTopic(chatName)
	for i := 0; i < envelopesCount; i++ {
		params := whisper.MessageParams{
			Topic:    topic,
			WorkTime: 10,
			PoW:      2.0,
			Payload:  []byte("some-payload"),
			KeySym:   publicChatSymKey,
		}
		sentMessage, err := whisper.NewSentMessage(&params)
		s.Require().NoError(err)
		envelope, err := sentMessage.Wrap(&params, time.Now())
		s.Require().NoError(err)

		mailServer.Archive(envelope)
	}

	// Start a second mail server which would like to sync the state.
	emptyMailbox, stopEmptyMailbox := s.startMailboxBackend("empty")
	defer stopEmptyMailbox()
	s.Require().True(emptyMailbox.IsNodeRunning())

	emptyMailboxEnode := emptyMailbox.StatusNode().Server().Self().URLv4()

	errCh := helpers.WaitForPeerAsync(emptyMailbox.StatusNode().Server(), mailboxEnode, p2p.PeerEventTypeAdd, 5*time.Second)
	s.Require().NoError(emptyMailbox.StatusNode().AddPeer(mailboxEnode))
	s.Require().NoError(<-errCh)

	emptyMailboxWhisperService, err := emptyMailbox.StatusNode().WhisperService()
	s.Require().NoError(err)

	err = utils.Eventually(func() error {
		return emptyMailboxWhisperService.AllowP2PMessagesFromPeer(
			mailbox.StatusNode().Server().Self().ID().Bytes(),
		)
	}, time.Second*5, time.Millisecond*100)
	s.Require().NoError(err)

	emptyMailboxRPCClient := emptyMailbox.StatusNode().RPCPrivateClient()
	s.Require().NotNil(emptyMailboxRPCClient)

	// Ask to sync the first batch of messages.
	// We artificially set Limit to 1 in order to test pagination.
	ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
	defer cancel()

	var syncMessagesResponse shhext.SyncMessagesResponse
	err = emptyMailboxRPCClient.CallContext(
		ctx,
		&syncMessagesResponse,
		"shhext_syncMessages",
		shhext.SyncMessagesRequest{
			MailServerPeer: mailbox.StatusNode().Server().Self().URLv4(),
			From:           uint32(time.Now().Add(-time.Hour).Unix()),
			To:             uint32(time.Now().Unix()),
			Limit:          1,
		},
	)
	s.Require().NoError(err)
	s.Require().NotEmpty(syncMessagesResponse.Cursor)
	s.Require().Empty(syncMessagesResponse.Error)

	// Ask to sync the rest of messages.
	ctx, cancel = context.WithTimeout(context.Background(), time.Second*5)
	defer cancel()

	err = emptyMailboxRPCClient.CallContext(
		ctx,
		&syncMessagesResponse,
		"shhext_syncMessages",
		shhext.SyncMessagesRequest{
			MailServerPeer: mailbox.StatusNode().Server().Self().URLv4(),
			From:           uint32(time.Now().Add(-time.Hour).Unix()),
			To:             uint32(time.Now().Unix()),
			Limit:          10,
			Cursor:         syncMessagesResponse.Cursor,
		},
	)
	s.Require().NoError(err)
	s.Require().Empty(syncMessagesResponse.Cursor)
	s.Require().Empty(syncMessagesResponse.Error)

	// create and start a client
	client, stop := s.startBackend("client")
	defer stop()
	s.Require().True(client.IsNodeRunning())
	clientWhisperService, err := client.StatusNode().WhisperService()
	s.Require().NoError(err)
	clientRPCClient := client.StatusNode().RPCPrivateClient()

	// create filter for messages
	messagesKeyID, err := clientWhisperService.AddSymKeyFromPassword(chatName)
	s.Require().NoError(err)
	messageFilterID := s.createGroupChatMessageFilter(clientRPCClient, messagesKeyID, topic.String())

	// add mailbox password
	mailServerKeyID, err := clientWhisperService.AddSymKeyFromPassword(mailboxPassword)
	s.Require().NoError(err)

	// add the second mail server as a peer
	errCh = helpers.WaitForPeerAsync(
		client.StatusNode().Server(),
		emptyMailboxEnode,
		p2p.PeerEventTypeAdd,
		5*time.Second)
	s.Require().NoError(client.StatusNode().AddPeer(emptyMailboxEnode))
	s.Require().NoError(<-errCh)

	// request for messages
	mailboxResponseWatcher := make(chan whisper.EnvelopeEvent, 1024)
	sub := clientWhisperService.SubscribeEnvelopeEvents(mailboxResponseWatcher)
	defer sub.Unsubscribe()

	requestID := s.requestHistoricMessagesFromLast12Hours(
		clientWhisperService,
		clientRPCClient,
		emptyMailboxEnode,
		mailServerKeyID,
		topic.String(),
		0,
		"",
	)
	response := s.waitForMailServerResponse(mailboxResponseWatcher, requestID)
	s.Require().NotEqual(common.Hash{}.Bytes(), response.LastEnvelopeHash.Bytes())

	// get messages
	messages := s.getMessagesByMessageFilterID(clientRPCClient, messageFilterID)
	// call once again because some messages can be delievered later
	time.Sleep(time.Millisecond * 500)
	messages = append(
		messages,
		s.getMessagesByMessageFilterID(clientRPCClient, messageFilterID)...)

	s.Require().Len(messages, envelopesCount)
}

func (s *WhisperMailboxSuite) waitForEnvelopeEvents(events chan whisper.EnvelopeEvent, hashes []string, event whisper.EventType) {
	check := make(map[string]struct{})
	for _, hash := range hashes {
		check[hash] = struct{}{}
	}

	timeout := time.NewTimer(time.Second * 5)
	for {
		select {
		case e := <-events:
			if e.Event == event {
				delete(check, e.Hash.String())
				if len(check) == 0 {
					timeout.Stop()
					return
				}
			}
		case <-timeout.C:
			s.FailNow("timed out while waiting for event on envelopes", "event: %s", event)
		}
	}
}

func (s *WhisperMailboxSuite) waitForMailServerResponse(events chan whisper.EnvelopeEvent, requestID common.Hash) *whisper.MailServerResponse {
	timeout := time.NewTimer(time.Second * 5)
	for {
		select {
		case event := <-events:
			if event.Event == whisper.EventMailServerRequestCompleted && event.Hash == requestID {
				timeout.Stop()
				resp, ok := event.Data.(*whisper.MailServerResponse)
				if !ok {
					s.FailNow("mailserver response error", "expected whisper.MailServerResponse, got: %+v", resp)
				}

				return resp
			}
		case <-timeout.C:
			s.FailNow("timed out while waiting for mailserver response")
		}
	}
}

func newGroupChatParams(symkey []byte, topic whisper.TopicType) groupChatParams {
	groupChatKeyStr := hexutil.Bytes(symkey).String()
	return groupChatParams{
		Key:   groupChatKeyStr,
		Topic: topic.String(),
	}
}

type groupChatParams struct {
	Key   string
	Topic string
}

func (d *groupChatParams) Decode(i string) error {
	b, err := hexutil.Decode(i)
	if err != nil {
		return err
	}
	return json.Unmarshal(b, &d)
}

func (d *groupChatParams) Encode() (string, error) {
	payload, err := json.Marshal(d)
	if err != nil {
		return "", err
	}
	return hexutil.Bytes(payload).String(), nil
}

// Start status node.
func (s *WhisperMailboxSuite) startBackend(name string) (*api.GethStatusBackend, func()) {
	datadir := filepath.Join(utils.RootDir, ".ethereumtest/mailbox", name)
	backend := api.NewGethStatusBackend()
	nodeConfig, err := utils.MakeTestNodeConfig(utils.GetNetworkID())
	nodeConfig.DataDir = datadir
	nodeConfig.KeyStoreDir = filepath.Join(datadir, "keystore")
	s.Require().NoError(err)
	s.Require().NoError(backend.AccountManager().InitKeystore(nodeConfig.KeyStoreDir))

	s.Require().False(backend.IsNodeRunning())

	nodeConfig.WhisperConfig.LightClient = true

	if addr, err := utils.GetRemoteURL(); err == nil {
		nodeConfig.UpstreamConfig.Enabled = true
		nodeConfig.UpstreamConfig.URL = addr
	}

	s.Require().NoError(backend.StartNode(nodeConfig))
	s.Require().True(backend.IsNodeRunning())

	return backend, func() {
		s.True(backend.IsNodeRunning())
		s.NoError(backend.StopNode())
		s.False(backend.IsNodeRunning())
		err = os.RemoveAll(datadir)
		s.Require().NoError(err)
	}

}

// Start mailbox node.
func (s *WhisperMailboxSuite) startMailboxBackend(name string) (*api.GethStatusBackend, func()) {
	return s.startMailboxBackendWithCallback(name, nil)
}

func (s *WhisperMailboxSuite) startMailboxBackendWithCallback(
	name string,
	callback func(*params.NodeConfig),
) (*api.GethStatusBackend, func()) {
	if name == "" {
		name = "mailserver"
	}

	mailboxConfig, err := utils.MakeTestNodeConfig(utils.GetNetworkID())
	s.Require().NoError(err)

	mailboxBackend := api.NewGethStatusBackend()
	s.Require().NoError(mailboxBackend.AccountManager().InitKeystore(mailboxConfig.KeyStoreDir))
	datadir := filepath.Join(utils.RootDir, ".ethereumtest/mailbox", name)

	mailboxConfig.LightEthConfig.Enabled = false
	mailboxConfig.WhisperConfig.Enabled = true
	mailboxConfig.KeyStoreDir = datadir
	mailboxConfig.WhisperConfig.EnableMailServer = true
	mailboxConfig.WhisperConfig.MailServerPassword = "status-offline-inbox"
	mailboxConfig.WhisperConfig.DataDir = filepath.Join(datadir, "data")
	mailboxConfig.DataDir = datadir

	if callback != nil {
		callback(mailboxConfig)
	}

	s.Require().False(mailboxBackend.IsNodeRunning())
	s.Require().NoError(mailboxBackend.StartNode(mailboxConfig))
	s.Require().True(mailboxBackend.IsNodeRunning())
	return mailboxBackend, func() {
		s.True(mailboxBackend.IsNodeRunning())
		s.NoError(mailboxBackend.StopNode())
		s.False(mailboxBackend.IsNodeRunning())
		err := os.RemoveAll(datadir)
		s.Require().NoError(err)
	}
}

// createPrivateChatMessageFilter create message filter with asymmetric encryption.
func (s *WhisperMailboxSuite) createPrivateChatMessageFilter(rpcCli *rpc.Client, privateKeyID string, topic string) string {
	resp := rpcCli.CallRaw(`{
			"jsonrpc": "2.0",
			"method": "shh_newMessageFilter", "params": [
				{"privateKeyID": "` + privateKeyID + `", "topics": [ "` + topic + `"], "allowP2P":true}
			],
			"id": 1
		}`)

	msgFilterResp := returnedIDResponse{}
	err := json.Unmarshal([]byte(resp), &msgFilterResp)
	messageFilterID := msgFilterResp.Result
	s.Require().NoError(err)
	s.Require().Nil(msgFilterResp.Error)
	s.Require().NotEqual("", messageFilterID, resp)
	return messageFilterID
}

// createGroupChatMessageFilter create message filter with symmetric encryption.
func (s *WhisperMailboxSuite) createGroupChatMessageFilter(rpcCli *rpc.Client, symkeyID string, topic string) string {
	resp := rpcCli.CallRaw(`{
			"jsonrpc": "2.0",
			"method": "shh_newMessageFilter", "params": [
				{"symKeyID": "` + symkeyID + `", "topics": ["` + topic + `"], "allowP2P": true}
			],
			"id": 1
		}`)

	msgFilterResp := returnedIDResponse{}
	err := json.Unmarshal([]byte(resp), &msgFilterResp)
	messageFilterID := msgFilterResp.Result
	s.Require().NoError(err)
	s.Require().Nil(msgFilterResp.Error)
	s.Require().NotEqual("", messageFilterID, resp)
	return messageFilterID
}

func (s *WhisperMailboxSuite) postMessageToPrivate(rpcCli *rpc.Client, recipientPubkey string, topic string, payload string) string {
	resp := rpcCli.CallRaw(`{
		"jsonrpc": "2.0",
		"method": "shh_post",
		"params": [
			{
			"pubKey": "` + recipientPubkey + `",
			"topic": "` + topic + `",
			"payload": "` + payload + `",
			"powTarget": 0.001,
			"powTime": 2
			}
		],
		"id": 1}`)
	postResp := baseRPCResponse{}
	err := json.Unmarshal([]byte(resp), &postResp)
	s.Require().NoError(err)
	s.Require().Nil(postResp.Error)

	return postResp.Result.(string)
}

func (s *WhisperMailboxSuite) postMessageToGroup(rpcCli *rpc.Client, groupChatKeyID string, topic string, payload string) string {
	resp := rpcCli.CallRaw(`{
		"jsonrpc": "2.0",
		"method": "shh_post",
		"params": [
			{
			"symKeyID": "` + groupChatKeyID + `",
			"topic": "` + topic + `",
			"payload": "` + payload + `",
			"powTarget": 0.001,
			"powTime": 2
			}
		],
		"id": 1}`)
	postResp := baseRPCResponse{}
	err := json.Unmarshal([]byte(resp), &postResp)
	s.Require().NoError(err)
	s.Require().Nil(postResp.Error)

	hash, ok := postResp.Result.(string)
	if !ok {
		s.FailNow("error decoding result", "expected string, got: %+v", postResp.Result)
	}

	if !strings.HasPrefix(hash, "0x") {
		s.FailNow("hash format error", "expected hex string, got: %s", hash)
	}

	return hash
}

// getMessagesByMessageFilterID gets received messages by messageFilterID.
func (s *WhisperMailboxSuite) getMessagesByMessageFilterID(rpcCli *rpc.Client, messageFilterID string) []map[string]interface{} {
	resp := rpcCli.CallRaw(`{
		"jsonrpc": "2.0",
		"method": "shh_getFilterMessages",
		"params": ["` + messageFilterID + `"],
		"id": 1}`)
	messages := getFilterMessagesResponse{}
	err := json.Unmarshal([]byte(resp), &messages)
	s.Require().NoError(err)
	s.Require().Nil(messages.Error)
	return messages.Result
}

// addSymKey added symkey to node and return symkeyID.
func (s *WhisperMailboxSuite) addSymKey(rpcCli *rpc.Client, symkey string) string {
	resp := rpcCli.CallRaw(`{"jsonrpc":"2.0","method":"shh_addSymKey",
			"params":["` + symkey + `"],
			"id":1}`)
	symkeyAddResp := returnedIDResponse{}
	err := json.Unmarshal([]byte(resp), &symkeyAddResp)
	s.Require().NoError(err)
	s.Require().Nil(symkeyAddResp.Error)
	symkeyID := symkeyAddResp.Result
	s.Require().NotEmpty(symkeyID)
	return symkeyID
}

// requestHistoricMessagesFromLast12Hours asks a mailnode to resend messages from last 12 hours.
func (s *WhisperMailboxSuite) requestHistoricMessagesFromLast12Hours(w *whisper.Whisper, rpcCli *rpc.Client, mailboxEnode, mailServerKeyID, topic string, limit int, cursor string) common.Hash {
	currentTime := w.GetCurrentTime()
	from := currentTime.Add(-12 * time.Hour)
	to := currentTime
	return s.requestHistoricMessages(w, rpcCli, mailboxEnode, mailServerKeyID, topic, from, to, limit, cursor)
}

// requestHistoricMessages asks a mailnode to resend messages.
func (s *WhisperMailboxSuite) requestHistoricMessages(w *whisper.Whisper, rpcCli *rpc.Client, mailboxEnode, mailServerKeyID, topic string, from, to time.Time, limit int, cursor string) common.Hash {
	resp := rpcCli.CallRaw(`{
		"jsonrpc": "2.0",
		"id": 2,
		"method": "shhext_requestMessages",
		"params": [{
					"mailServerPeer":"` + mailboxEnode + `",
					"topic":"` + topic + `",
					"symKeyID":"` + mailServerKeyID + `",
					"from":` + strconv.FormatInt(from.Unix(), 10) + `,
					"to":` + strconv.FormatInt(to.Unix(), 10) + `,
					"limit": ` + fmt.Sprintf("%d", limit) + `,
					"cursor": "` + cursor + `"
		}]
	}`)
	reqMessagesResp := baseRPCResponse{}
	err := json.Unmarshal([]byte(resp), &reqMessagesResp)
	s.Require().NoError(err)
	s.Require().Nil(reqMessagesResp.Error)

	switch hash := reqMessagesResp.Result.(type) {
	case string:
		s.Require().True(strings.HasPrefix(hash, "0x"))
		b, err := hex.DecodeString(hash[2:])
		s.Require().NoError(err)
		return common.BytesToHash(b)
	default:
		s.Failf("failed reading shh_newMessageFilter result", "expected a hash, got: %+v", reqMessagesResp.Result)
	}

	return common.Hash{}
}

func (s *WhisperMailboxSuite) createPublicChatTopic(name string) whisper.TopicType {
	h := sha3.NewLegacyKeccak256()
	_, err := h.Write([]byte(name))
	if err != nil {
		s.Fail("error generating topic", "failed gerating topic from chat name, %+v", err)
	}
	return whisper.BytesToTopic(h.Sum(nil))
}

func (s *WhisperMailboxSuite) joinPublicChat(w *whisper.Whisper, rpcClient *rpc.Client, name string) (string, whisper.TopicType, string) {
	keyID, err := w.AddSymKeyFromPassword(name)
	s.Require().NoError(err)

	topic := s.createPublicChatTopic(name)

	filterID := s.createGroupChatMessageFilter(rpcClient, keyID, topic.String())

	return keyID, topic, filterID
}

type getFilterMessagesResponse struct {
	Result []map[string]interface{}
	Error  interface{}
}

type returnedIDResponse struct {
	Result string
	Error  interface{}
}
type baseRPCResponse struct {
	Result interface{}
	Error  interface{}
}