package network

import (
	"net"
	"strconv"
	"testing"
	"time"

	"github.com/nspcc-dev/neo-go/pkg/network/capability"
	"github.com/nspcc-dev/neo-go/pkg/network/payload"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

func TestGetBlocksByIndex(t *testing.T) {
	s := newTestServer(t, ServerConfig{Port: 0, UserAgent: "/test/"})
	ps := make([]*localPeer, 10)
	expectsCmd := make([]CommandType, 10)
	expectedHeight := make([][]uint32, 10)
	start := s.chain.BlockHeight()
	for i := range ps {
		i := i
		ps[i] = newLocalPeer(t, s)
		ps[i].messageHandler = func(t *testing.T, msg *Message) {
			require.Equal(t, expectsCmd[i], msg.Command)
			if expectsCmd[i] == CMDGetBlockByIndex {
				p, ok := msg.Payload.(*payload.GetBlockByIndex)
				require.True(t, ok)
				require.Contains(t, expectedHeight[i], p.IndexStart)
				expectsCmd[i] = CMDPong
			} else if expectsCmd[i] == CMDPong {
				expectsCmd[i] = CMDGetBlockByIndex
			}
		}
		expectsCmd[i] = CMDGetBlockByIndex
		expectedHeight[i] = []uint32{start + 1}
	}
	go s.transport.Accept()

	nonce := uint32(0)
	checkPingRespond := func(t *testing.T, peerIndex int, peerHeight uint32, hs ...uint32) {
		nonce++
		expectedHeight[peerIndex] = hs
		require.NoError(t, s.handlePing(ps[peerIndex], payload.NewPing(peerHeight, nonce)))
	}

	// Send all requests for all chunks.
	checkPingRespond(t, 0, 5000, 1)
	checkPingRespond(t, 1, 5000, 1+payload.MaxHashesCount)
	checkPingRespond(t, 2, 5000, 1+2*payload.MaxHashesCount)
	checkPingRespond(t, 3, 5000, 1+3*payload.MaxHashesCount)

	// Receive some blocks.
	s.chain.(*testChain).blockheight = 2123

	// Minimum chunk has priority.
	checkPingRespond(t, 5, 5000, 2124)
	checkPingRespond(t, 6, 5000, 2624)
	// Request minimal height for peers behind.
	checkPingRespond(t, 7, 3100, 2124)
	checkPingRespond(t, 8, 5000, 3124)
	checkPingRespond(t, 9, 5000, 3624)
	// Request random height after that.
	checkPingRespond(t, 1, 5000, 2124, 2624, 3124, 3624)
	checkPingRespond(t, 2, 5000, 2124, 2624, 3124, 3624)
	checkPingRespond(t, 3, 5000, 2124, 2624, 3124, 3624)
}

func TestSendVersion(t *testing.T) {
	var (
		s = newTestServer(t, ServerConfig{Port: 0, UserAgent: "/test/"})
		p = newLocalPeer(t, s)
	)
	// we need to set listener at least to handle dynamic port correctly
	go s.transport.Accept()
	require.Eventually(t, func() bool { return s.transport.Address() != "" }, time.Second, 10*time.Millisecond)
	p.messageHandler = func(t *testing.T, msg *Message) {
		// listener is already set, so Address() gives us proper address with port
		_, p, err := net.SplitHostPort(s.transport.Address())
		assert.NoError(t, err)
		port, err := strconv.ParseUint(p, 10, 16)
		assert.NoError(t, err)
		assert.Equal(t, CMDVersion, msg.Command)
		assert.IsType(t, msg.Payload, &payload.Version{})
		version := msg.Payload.(*payload.Version)
		assert.NotZero(t, version.Nonce)
		assert.Equal(t, 1, len(version.Capabilities))
		assert.ElementsMatch(t, []capability.Capability{
			{
				Type: capability.TCPServer,
				Data: &capability.Server{
					Port: uint16(port),
				},
			},
		}, version.Capabilities)
		assert.Equal(t, uint32(0), version.Version)
		assert.Equal(t, []byte("/test/"), version.UserAgent)
	}

	require.NoError(t, p.SendVersion())
}

// Server should reply with a verack after receiving a valid version.
func TestVerackAfterHandleVersionCmd(t *testing.T) {
	var (
		s = newTestServer(t, ServerConfig{})
		p = newLocalPeer(t, s)
	)
	na, _ := net.ResolveTCPAddr("tcp", "0.0.0.0:3000")
	p.netaddr = *na

	// Should have a verack
	p.messageHandler = func(t *testing.T, msg *Message) {
		assert.Equal(t, CMDVerack, msg.Command)
	}
	capabilities := []capability.Capability{
		{
			Type: capability.FullNode,
			Data: &capability.Node{
				StartHeight: 0,
			},
		},
		{
			Type: capability.TCPServer,
			Data: &capability.Server{
				Port: 3000,
			},
		},
	}
	version := payload.NewVersion(0, 1337, "/NEO-GO/", capabilities)

	require.NoError(t, s.handleVersionCmd(p, version))
}

// Server should not reply with a verack after receiving a
// invalid version and disconnects the peer.
func TestServerNotSendsVerack(t *testing.T) {
	var (
		s  = newTestServer(t, ServerConfig{Net: 56753})
		p  = newLocalPeer(t, s)
		p2 = newLocalPeer(t, s)
	)
	s.id = 1
	finished := make(chan struct{})
	go func() {
		s.run()
		close(finished)
	}()
	defer func() {
		// close via quit as server was started via `run()`, not `Start()`
		close(s.quit)
		<-finished
	}()

	na, _ := net.ResolveTCPAddr("tcp", "0.0.0.0:3000")
	p.netaddr = *na
	p2.netaddr = *na
	s.register <- p

	capabilities := []capability.Capability{
		{
			Type: capability.FullNode,
			Data: &capability.Node{
				StartHeight: 0,
			},
		},
		{
			Type: capability.TCPServer,
			Data: &capability.Server{
				Port: 3000,
			},
		},
	}
	// identical id's
	version := payload.NewVersion(56753, 1, "/NEO-GO/", capabilities)
	err := s.handleVersionCmd(p, version)
	assert.NotNil(t, err)
	assert.Equal(t, errIdenticalID, err)

	// Different IDs, but also different magics
	version.Nonce = 2
	version.Magic = 56752
	err = s.handleVersionCmd(p, version)
	assert.NotNil(t, err)
	assert.Equal(t, errInvalidNetwork, err)

	// Different IDs and same network, make handshake pass.
	version.Magic = 56753
	require.NoError(t, s.handleVersionCmd(p, version))
	require.NoError(t, p.HandleVersionAck())
	require.Equal(t, true, p.Handshaked())

	// Second handshake from the same peer should fail.
	s.register <- p2
	err = s.handleVersionCmd(p2, version)
	assert.NotNil(t, err)
	require.Equal(t, errAlreadyConnected, err)
}