package node

import (
	"errors"
	"io/ioutil"
	"math"
	"os"
	"path"
	"reflect"
	"testing"
	"time"

	"github.com/ethereum/go-ethereum/les"
	gethnode "github.com/ethereum/go-ethereum/node"
	"github.com/ethereum/go-ethereum/p2p"
	"github.com/ethereum/go-ethereum/p2p/discover"
	whisper "github.com/ethereum/go-ethereum/whisper/whisperv6"

	"github.com/status-im/status-go/params"
	"github.com/stretchr/testify/require"
)

func TestStatusNodeStart(t *testing.T) {
	var err error

	config := params.NodeConfig{}
	n := New()

	// checks before node is started
	require.Nil(t, n.GethNode())
	require.Nil(t, n.Config())
	require.Nil(t, n.RPCClient())
	require.Equal(t, 0, n.PeerCount())
	_, err = n.AccountManager()
	require.EqualError(t, err, ErrNoGethNode.Error())
	_, err = n.AccountKeyStore()
	require.EqualError(t, err, ErrNoGethNode.Error())

	// start node
	require.NoError(t, n.Start(&config))

	// checks after node is started
	require.True(t, n.IsRunning())
	require.NotNil(t, n.GethNode())
	require.NotNil(t, n.Config())
	require.NotNil(t, n.RPCClient())
	require.Equal(t, 0, n.PeerCount())
	accountManager, err := n.AccountManager()
	require.Nil(t, err)
	require.NotNil(t, accountManager)
	keyStore, err := n.AccountKeyStore()
	require.Nil(t, err)
	require.NotNil(t, keyStore)
	// try to start already started node
	require.EqualError(t, n.Start(&config), ErrNodeRunning.Error())

	// stop node
	require.NoError(t, n.Stop())
	// try to stop already stopped node
	require.EqualError(t, n.Stop(), ErrNoRunningNode.Error())

	// checks after node is stopped
	require.Nil(t, n.GethNode())
	require.Nil(t, n.RPCClient())
	require.Equal(t, 0, n.PeerCount())
	_, err = n.AccountManager()
	require.EqualError(t, err, ErrNoGethNode.Error())
	_, err = n.AccountKeyStore()
	require.EqualError(t, err, ErrNoGethNode.Error())
}

func TestStatusNodeWithDataDir(t *testing.T) {
	var err error

	dir, err := ioutil.TempDir("", "status-node-test")
	require.NoError(t, err)
	defer func() {
		require.NoError(t, os.RemoveAll(dir))
	}()

	// keystore directory
	keyStoreDir := path.Join(dir, "keystore")
	err = os.MkdirAll(keyStoreDir, os.ModePerm)
	require.NoError(t, err)

	config := params.NodeConfig{
		DataDir:     dir,
		KeyStoreDir: keyStoreDir,
	}
	n := New()

	require.NoError(t, n.Start(&config))
	require.NoError(t, n.Stop())
}

func TestStatusNodeServiceGetters(t *testing.T) {
	config := params.NodeConfig{
		WhisperConfig: &params.WhisperConfig{
			Enabled: true,
		},
		LightEthConfig: &params.LightEthConfig{
			Enabled: true,
		},
	}
	n := New()

	var (
		instance interface{}
		err      error
	)

	services := []struct {
		getter func() (interface{}, error)
		typ    reflect.Type
	}{
		{
			getter: func() (interface{}, error) {
				return n.WhisperService()
			},
			typ: reflect.TypeOf(&whisper.Whisper{}),
		},
		{
			getter: func() (interface{}, error) {
				return n.LightEthereumService()
			},
			typ: reflect.TypeOf(&les.LightEthereum{}),
		},
	}

	for _, service := range services {
		t.Run(service.typ.String(), func(t *testing.T) {
			// checks before node is started
			instance, err = service.getter()
			require.EqualError(t, err, ErrNoRunningNode.Error())
			require.Nil(t, instance)

			// start node
			require.NoError(t, n.Start(&config))

			// checks after node is started
			instance, err = service.getter()
			require.NoError(t, err)
			require.NotNil(t, instance)
			require.Equal(t, service.typ, reflect.TypeOf(instance))

			// stop node
			require.NoError(t, n.Stop())

			// checks after node is stopped
			instance, err = service.getter()
			require.EqualError(t, err, ErrNoRunningNode.Error())
			require.Nil(t, instance)
		})
	}
}

func TestStatusNodeAddPeer(t *testing.T) {
	var err error

	peer, err := gethnode.New(&gethnode.Config{
		P2P: p2p.Config{
			MaxPeers:    math.MaxInt32,
			NoDiscovery: true,
			ListenAddr:  ":0",
		},
	})
	require.NoError(t, err)
	require.NoError(t, peer.Start())
	defer func() { require.NoError(t, peer.Stop()) }()
	peerURL := peer.Server().Self().String()

	n := New()

	// checks before node is started
	require.EqualError(t, n.AddPeer(peerURL), ErrNoRunningNode.Error())

	// start status node
	config := params.NodeConfig{
		MaxPeers: math.MaxInt32,
	}
	require.NoError(t, n.Start(&config))
	defer func() { require.NoError(t, n.Stop()) }()

	errCh := waitForPeerAsync(n, peerURL, p2p.PeerEventTypeAdd, time.Second*5)

	// checks after node is started
	require.NoError(t, n.AddPeer(peerURL))
	require.NoError(t, <-errCh)
	require.Equal(t, 1, n.PeerCount())
}

func TestStatusNodeReconnectStaticPeers(t *testing.T) {
	var err error

	peer, err := gethnode.New(&gethnode.Config{
		P2P: p2p.Config{
			MaxPeers:    math.MaxInt32,
			NoDiscovery: true,
			ListenAddr:  ":0",
		},
	})
	require.NoError(t, err)
	require.NoError(t, peer.Start())
	defer func() { require.NoError(t, peer.Stop()) }()

	var errCh <-chan error

	peerURL := peer.Server().Self().String()
	n := New()

	// checks before node is started
	require.EqualError(t, n.ReconnectStaticPeers(), ErrNoRunningNode.Error())

	// start status node
	config := params.NodeConfig{
		MaxPeers: math.MaxInt32,
		ClusterConfig: &params.ClusterConfig{
			Enabled:     true,
			StaticNodes: []string{peerURL},
		},
	}
	require.NoError(t, n.Start(&config))
	defer func() { require.NoError(t, n.Stop()) }()

	// checks after node is started
	// it may happen that the peer is already connected
	// because it was already added to `StaticNodes`
	connected, err := isPeerConnected(n, peerURL)
	require.NoError(t, err)
	if !connected {
		errCh = waitForPeerAsync(n, peerURL, p2p.PeerEventTypeAdd, time.Second*30)
		require.NoError(t, <-errCh)
	}
	require.Equal(t, 1, n.PeerCount())
	require.Equal(t, peer.Server().Self().ID.String(), n.GethNode().Server().PeersInfo()[0].ID)

	// reconnect static peers
	errDropCh := waitForPeerAsync(n, peerURL, p2p.PeerEventTypeDrop, time.Second*30)
	// it takes at least 30 seconds to bring back previously connected peer
	errAddCh := waitForPeerAsync(n, peerURL, p2p.PeerEventTypeAdd, time.Second*60)
	require.NoError(t, n.ReconnectStaticPeers())
	// first check if a peer gets disconnected
	require.NoError(t, <-errDropCh)
	require.NoError(t, <-errAddCh)
}

func isPeerConnected(node *StatusNode, peerURL string) (bool, error) {
	if !node.IsRunning() {
		return false, ErrNoRunningNode
	}

	parsedPeer, err := discover.ParseNode(peerURL)
	if err != nil {
		return false, err
	}

	server := node.GethNode().Server()

	for _, peer := range server.PeersInfo() {
		if peer.ID == parsedPeer.ID.String() {
			return true, nil
		}
	}

	return false, nil
}

func waitForPeer(node *StatusNode, peerURL string, eventType p2p.PeerEventType, timeout time.Duration, subscribed chan struct{}) error {
	if !node.IsRunning() {
		return ErrNoRunningNode
	}

	parsedPeer, err := discover.ParseNode(peerURL)
	if err != nil {
		return err
	}

	server := node.GethNode().Server()
	ch := make(chan *p2p.PeerEvent)
	subscription := server.SubscribeEvents(ch)
	defer subscription.Unsubscribe()

	close(subscribed)

	for {
		select {
		case ev := <-ch:
			if ev.Type == eventType && ev.Peer == parsedPeer.ID {
				return nil
			}
		case err := <-subscription.Err():
			if err != nil {
				return err
			}
		case <-time.After(timeout):
			return errors.New("wait for peer: timeout")
		}
	}
}

func waitForPeerAsync(node *StatusNode, peerURL string, eventType p2p.PeerEventType, timeout time.Duration) <-chan error {
	subscribed := make(chan struct{})
	errCh := make(chan error)
	go func() {
		errCh <- waitForPeer(node, peerURL, eventType, timeout, subscribed)
	}()

	<-subscribed

	return errCh
}