//go:build e2e_testing
// +build e2e_testing

package e2e

import (
	"fmt"
	"io"
	"net/netip"
	"os"
	"testing"
	"time"

	"dario.cat/mergo"
	"github.com/google/gopacket"
	"github.com/google/gopacket/layers"
	"github.com/sirupsen/logrus"
	"github.com/slackhq/nebula"
	"github.com/slackhq/nebula/cert"
	"github.com/slackhq/nebula/config"
	"github.com/slackhq/nebula/e2e/router"
	"github.com/stretchr/testify/assert"
	"gopkg.in/yaml.v2"
)

type m map[string]interface{}

// newSimpleServer creates a nebula instance with many assumptions
func newSimpleServer(caCrt cert.Certificate, caKey []byte, name string, sVpnIpNet string, overrides m) (*nebula.Control, netip.Prefix, netip.AddrPort, *config.C) {
	l := NewTestLogger()

	vpnIpNet, err := netip.ParsePrefix(sVpnIpNet)
	if err != nil {
		panic(err)
	}

	var udpAddr netip.AddrPort
	if vpnIpNet.Addr().Is4() {
		budpIp := vpnIpNet.Addr().As4()
		budpIp[1] -= 128
		udpAddr = netip.AddrPortFrom(netip.AddrFrom4(budpIp), 4242)
	} else {
		budpIp := vpnIpNet.Addr().As16()
		budpIp[13] -= 128
		udpAddr = netip.AddrPortFrom(netip.AddrFrom16(budpIp), 4242)
	}
	_, _, myPrivKey, myPEM := NewTestCert(caCrt, caKey, name, time.Now(), time.Now().Add(5*time.Minute), []netip.Prefix{vpnIpNet}, nil, []string{})

	caB, err := caCrt.MarshalPEM()
	if err != nil {
		panic(err)
	}

	mc := m{
		"pki": m{
			"ca":   string(caB),
			"cert": string(myPEM),
			"key":  string(myPrivKey),
		},
		//"tun": m{"disabled": true},
		"firewall": m{
			"outbound": []m{{
				"proto": "any",
				"port":  "any",
				"host":  "any",
			}},
			"inbound": []m{{
				"proto": "any",
				"port":  "any",
				"host":  "any",
			}},
		},
		//"handshakes": m{
		//	"try_interval": "1s",
		//},
		"listen": m{
			"host": udpAddr.Addr().String(),
			"port": udpAddr.Port(),
		},
		"logging": m{
			"timestamp_format": fmt.Sprintf("%v 15:04:05.000000", name),
			"level":            l.Level.String(),
		},
		"timers": m{
			"pending_deletion_interval": 2,
			"connection_alive_interval": 2,
		},
	}

	if overrides != nil {
		err = mergo.Merge(&overrides, mc, mergo.WithAppendSlice)
		if err != nil {
			panic(err)
		}
		mc = overrides
	}

	cb, err := yaml.Marshal(mc)
	if err != nil {
		panic(err)
	}

	c := config.NewC(l)
	c.LoadString(string(cb))

	control, err := nebula.Main(c, false, "e2e-test", l, nil)

	if err != nil {
		panic(err)
	}

	return control, vpnIpNet, udpAddr, c
}

type doneCb func()

func deadline(t *testing.T, seconds time.Duration) doneCb {
	timeout := time.After(seconds * time.Second)
	done := make(chan bool)
	go func() {
		select {
		case <-timeout:
			t.Fatal("Test did not finish in time")
		case <-done:
		}
	}()

	return func() {
		done <- true
	}
}

func assertTunnel(t *testing.T, vpnIpA, vpnIpB netip.Addr, controlA, controlB *nebula.Control, r *router.R) {
	// Send a packet from them to me
	controlB.InjectTunUDPPacket(vpnIpA, 80, 90, []byte("Hi from B"))
	bPacket := r.RouteForAllUntilTxTun(controlA)
	assertUdpPacket(t, []byte("Hi from B"), bPacket, vpnIpB, vpnIpA, 90, 80)

	// And once more from me to them
	controlA.InjectTunUDPPacket(vpnIpB, 80, 90, []byte("Hello from A"))
	aPacket := r.RouteForAllUntilTxTun(controlB)
	assertUdpPacket(t, []byte("Hello from A"), aPacket, vpnIpA, vpnIpB, 90, 80)
}

func assertHostInfoPair(t *testing.T, addrA, addrB netip.AddrPort, vpnIpA, vpnIpB netip.Addr, controlA, controlB *nebula.Control) {
	// Get both host infos
	hBinA := controlA.GetHostInfoByVpnIp(vpnIpB, false)
	assert.NotNil(t, hBinA, "Host B was not found by vpnIp in controlA")

	hAinB := controlB.GetHostInfoByVpnIp(vpnIpA, false)
	assert.NotNil(t, hAinB, "Host A was not found by vpnIp in controlB")

	// Check that both vpn and real addr are correct
	assert.Equal(t, vpnIpB, hBinA.VpnIp, "Host B VpnIp is wrong in control A")
	assert.Equal(t, vpnIpA, hAinB.VpnIp, "Host A VpnIp is wrong in control B")

	assert.Equal(t, addrB, hBinA.CurrentRemote, "Host B remote is wrong in control A")
	assert.Equal(t, addrA, hAinB.CurrentRemote, "Host A remote is wrong in control B")

	// Check that our indexes match
	assert.Equal(t, hBinA.LocalIndex, hAinB.RemoteIndex, "Host B local index does not match host A remote index")
	assert.Equal(t, hBinA.RemoteIndex, hAinB.LocalIndex, "Host B remote index does not match host A local index")

	//TODO: Would be nice to assert this memory
	//checkIndexes := func(name string, hm *HostMap, hi *HostInfo) {
	//	hBbyIndex := hmA.Indexes[hBinA.localIndexId]
	//	assert.NotNil(t, hBbyIndex, "Could not host info by local index in %s", name)
	//	assert.Equal(t, &hBbyIndex, &hBinA, "%s Indexes map did not point to the right host info", name)
	//
	//	//TODO: remote indexes are susceptible to collision
	//	hBbyRemoteIndex := hmA.RemoteIndexes[hBinA.remoteIndexId]
	//	assert.NotNil(t, hBbyIndex, "Could not host info by remote index in %s", name)
	//	assert.Equal(t, &hBbyRemoteIndex, &hBinA, "%s RemoteIndexes did not point to the right host info", name)
	//}
	//
	//// Check hostmap indexes too
	//checkIndexes("hmA", hmA, hBinA)
	//checkIndexes("hmB", hmB, hAinB)
}

func assertUdpPacket(t *testing.T, expected, b []byte, fromIp, toIp netip.Addr, fromPort, toPort uint16) {
	packet := gopacket.NewPacket(b, layers.LayerTypeIPv4, gopacket.Lazy)
	v4 := packet.Layer(layers.LayerTypeIPv4).(*layers.IPv4)
	assert.NotNil(t, v4, "No ipv4 data found")

	assert.Equal(t, fromIp.AsSlice(), []byte(v4.SrcIP), "Source ip was incorrect")
	assert.Equal(t, toIp.AsSlice(), []byte(v4.DstIP), "Dest ip was incorrect")

	udp := packet.Layer(layers.LayerTypeUDP).(*layers.UDP)
	assert.NotNil(t, udp, "No udp data found")

	assert.Equal(t, fromPort, uint16(udp.SrcPort), "Source port was incorrect")
	assert.Equal(t, toPort, uint16(udp.DstPort), "Dest port was incorrect")

	data := packet.ApplicationLayer()
	assert.NotNil(t, data)
	assert.Equal(t, expected, data.Payload(), "Data was incorrect")
}

func NewTestLogger() *logrus.Logger {
	l := logrus.New()

	v := os.Getenv("TEST_LOGS")
	if v == "" {
		l.SetOutput(io.Discard)
		l.SetLevel(logrus.PanicLevel)
		return l
	}

	switch v {
	case "2":
		l.SetLevel(logrus.DebugLevel)
	case "3":
		l.SetLevel(logrus.TraceLevel)
	default:
		l.SetLevel(logrus.InfoLevel)
	}

	return l
}