package controllers

import (
	"errors"
	"os"
	"reflect"
	"testing"
	"time"

	"github.com/cloudnativelabs/kube-router/app/watchers"
	"github.com/osrg/gobgp/config"
	gobgp "github.com/osrg/gobgp/server"

	v1core "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/client-go/kubernetes"
	"k8s.io/client-go/kubernetes/fake"
)

func Test_advertiseClusterIPs(t *testing.T) {
	testcases := []struct {
		name             string
		nrc              *NetworkRoutingController
		existingServices []*v1core.Service
		// the key is the subnet from the watch event
		watchEvents map[string]bool
	}{
		{
			"add bgp path for service with ClusterIP",
			&NetworkRoutingController{
				bgpServer: gobgp.NewBgpServer(),
			},
			[]*v1core.Service{
				{
					ObjectMeta: metav1.ObjectMeta{
						Name: "svc-1",
					},
					Spec: v1core.ServiceSpec{
						Type:      "ClusterIP",
						ClusterIP: "10.0.0.1",
					},
				},
			},
			map[string]bool{
				"10.0.0.1/32": true,
			},
		},
		{
			"add bgp path for service with ClusterIP/NodePort/LoadBalancer",
			&NetworkRoutingController{
				bgpServer: gobgp.NewBgpServer(),
			},
			[]*v1core.Service{
				{
					ObjectMeta: metav1.ObjectMeta{
						Name: "svc-1",
					},
					Spec: v1core.ServiceSpec{
						Type:      "ClusterIP",
						ClusterIP: "10.0.0.1",
					},
				},
				{
					ObjectMeta: metav1.ObjectMeta{
						Name: "svc-2",
					},
					Spec: v1core.ServiceSpec{
						Type:      "LoadBalancer",
						ClusterIP: "10.0.0.2",
					},
				},
				{
					ObjectMeta: metav1.ObjectMeta{
						Name: "svc-3",
					},
					Spec: v1core.ServiceSpec{
						Type:      "NodePort",
						ClusterIP: "10.0.0.3",
					},
				},
			},
			map[string]bool{
				"10.0.0.1/32": true,
				"10.0.0.2/32": true,
				"10.0.0.3/32": true,
			},
		},
		{
			"add bgp path for invalid service type",
			&NetworkRoutingController{
				bgpServer: gobgp.NewBgpServer(),
			},
			[]*v1core.Service{
				{
					ObjectMeta: metav1.ObjectMeta{
						Name: "svc-1",
					},
					Spec: v1core.ServiceSpec{
						Type:      "ClusterIP",
						ClusterIP: "10.0.0.1",
					},
				},
				{
					ObjectMeta: metav1.ObjectMeta{
						Name: "svc-2",
					},
					Spec: v1core.ServiceSpec{
						Type:      "AnotherType",
						ClusterIP: "10.0.0.2",
					},
				},
			},
			map[string]bool{
				"10.0.0.1/32": true,
			},
		},
		{
			"add bgp path for headless service",
			&NetworkRoutingController{
				bgpServer: gobgp.NewBgpServer(),
			},
			[]*v1core.Service{
				{
					ObjectMeta: metav1.ObjectMeta{
						Name: "svc-1",
					},
					Spec: v1core.ServiceSpec{
						Type:      "ClusterIP",
						ClusterIP: "10.0.0.1",
					},
				},
				{
					ObjectMeta: metav1.ObjectMeta{
						Name: "svc-2",
					},
					Spec: v1core.ServiceSpec{
						Type:      "ClusterIP",
						ClusterIP: "None",
					},
				},
				{
					ObjectMeta: metav1.ObjectMeta{
						Name: "svc-3",
					},
					Spec: v1core.ServiceSpec{
						Type:      "ClusterIP",
						ClusterIP: "",
					},
				},
			},
			map[string]bool{
				"10.0.0.1/32": true,
			},
		},
	}

	for _, testcase := range testcases {
		t.Run(testcase.name, func(t *testing.T) {
			go testcase.nrc.bgpServer.Serve()
			err := testcase.nrc.bgpServer.Start(&config.Global{
				Config: config.GlobalConfig{
					As:       1,
					RouterId: "10.0.0.0",
					Port:     10000,
				},
			})
			if err != nil {
				t.Fatalf("failed to start BGP server: %v", err)
			}
			defer testcase.nrc.bgpServer.Stop()
			w := testcase.nrc.bgpServer.Watch(gobgp.WatchBestPath(false))

			clientset := fake.NewSimpleClientset()

			_, err = watchers.StartServiceWatcher(clientset, 0)
			if err != nil {
				t.Fatalf("failed to initialize service watcher: %v", err)
			}

			err = createServices(clientset, testcase.existingServices)
			if err != nil {
				t.Fatalf("failed to create existing services: %v", err)
			}

			waitForListerWithTimeout(time.Second*10, t)
			testcase.nrc.advertiseClusterIPs()

			watchEvents := waitForBGPWatchEventWithTimeout(time.Second*10, len(testcase.watchEvents), w, t)
			for _, watchEvent := range watchEvents {
				for _, path := range watchEvent.PathList {
					if _, ok := testcase.watchEvents[path.GetNlri().String()]; ok {
						continue
					} else {
						t.Errorf("got unexpected path: %v", path.GetNlri().String())
					}
				}
			}
		})
	}
}

func Test_advertiseExternalIPs(t *testing.T) {
	testcases := []struct {
		name             string
		nrc              *NetworkRoutingController
		existingServices []*v1core.Service
		// the key is the subnet from the watch event
		watchEvents map[string]bool
	}{
		{
			"add bgp path for service with external IPs",
			&NetworkRoutingController{
				bgpServer: gobgp.NewBgpServer(),
			},
			[]*v1core.Service{
				{
					ObjectMeta: metav1.ObjectMeta{
						Name: "svc-1",
					},
					Spec: v1core.ServiceSpec{
						Type:        "ClusterIP",
						ClusterIP:   "10.0.0.1",
						ExternalIPs: []string{"1.1.1.1", "2.2.2.2"},
					},
				},
			},
			map[string]bool{
				"1.1.1.1/32": true,
				"2.2.2.2/32": true,
			},
		},
		{
			"add bgp path for services with external IPs of type ClusterIP/NodePort/LoadBalancer",
			&NetworkRoutingController{
				bgpServer: gobgp.NewBgpServer(),
			},
			[]*v1core.Service{
				{
					ObjectMeta: metav1.ObjectMeta{
						Name: "svc-1",
					},
					Spec: v1core.ServiceSpec{
						Type:        "ClusterIP",
						ClusterIP:   "10.0.0.1",
						ExternalIPs: []string{"1.1.1.1"},
					},
				},
				{
					ObjectMeta: metav1.ObjectMeta{
						Name: "svc-2",
					},
					Spec: v1core.ServiceSpec{
						Type:      "LoadBalancer",
						ClusterIP: "10.0.0.2",
						// ignored since LoadBalancer services don't
						// advertise external IPs.
						ExternalIPs: []string{"2.2.2.2"},
					},
				},
				{
					ObjectMeta: metav1.ObjectMeta{
						Name: "svc-3",
					},
					Spec: v1core.ServiceSpec{
						Type:        "NodePort",
						ClusterIP:   "10.0.0.3",
						ExternalIPs: []string{"3.3.3.3", "4.4.4.4"},
					},
				},
			},
			map[string]bool{
				"1.1.1.1/32": true,
				"3.3.3.3/32": true,
				"4.4.4.4/32": true,
			},
		},
		{
			"add bgp path for invalid service type",
			&NetworkRoutingController{
				bgpServer: gobgp.NewBgpServer(),
			},
			[]*v1core.Service{
				{
					ObjectMeta: metav1.ObjectMeta{
						Name: "svc-1",
					},
					Spec: v1core.ServiceSpec{
						Type:        "ClusterIP",
						ClusterIP:   "10.0.0.1",
						ExternalIPs: []string{"1.1.1.1"},
					},
				},
				{
					ObjectMeta: metav1.ObjectMeta{
						Name: "svc-2",
					},
					Spec: v1core.ServiceSpec{
						Type:        "AnotherType",
						ClusterIP:   "10.0.0.2",
						ExternalIPs: []string{"2.2.2.2"},
					},
				},
			},
			map[string]bool{
				"1.1.1.1/32": true,
			},
		},
		{
			"add bgp path for headless service",
			&NetworkRoutingController{
				bgpServer: gobgp.NewBgpServer(),
			},
			[]*v1core.Service{
				{
					ObjectMeta: metav1.ObjectMeta{
						Name: "svc-1",
					},
					Spec: v1core.ServiceSpec{
						Type:        "ClusterIP",
						ClusterIP:   "10.0.0.1",
						ExternalIPs: []string{"1.1.1.1"},
					},
				},
				{
					ObjectMeta: metav1.ObjectMeta{
						Name: "svc-2",
					},
					Spec: v1core.ServiceSpec{
						Type:        "ClusterIP",
						ClusterIP:   "None",
						ExternalIPs: []string{"2.2.2.2"},
					},
				},
				{
					ObjectMeta: metav1.ObjectMeta{
						Name: "svc-3",
					},
					Spec: v1core.ServiceSpec{
						Type:        "ClusterIP",
						ClusterIP:   "",
						ExternalIPs: []string{"3.3.3.3"},
					},
				},
			},
			map[string]bool{
				"1.1.1.1/32": true,
			},
		},
	}

	for _, testcase := range testcases {
		t.Run(testcase.name, func(t *testing.T) {
			go testcase.nrc.bgpServer.Serve()
			err := testcase.nrc.bgpServer.Start(&config.Global{
				Config: config.GlobalConfig{
					As:       1,
					RouterId: "10.0.0.0",
					Port:     10000,
				},
			})
			if err != nil {
				t.Fatalf("failed to start BGP server: %v", err)
			}
			defer testcase.nrc.bgpServer.Stop()
			w := testcase.nrc.bgpServer.Watch(gobgp.WatchBestPath(false))

			clientset := fake.NewSimpleClientset()

			_, err = watchers.StartServiceWatcher(clientset, 0)
			if err != nil {
				t.Fatalf("failed to initialize service watcher: %v", err)
			}

			err = createServices(clientset, testcase.existingServices)
			if err != nil {
				t.Fatalf("failed to create existing services: %v", err)
			}

			waitForListerWithTimeout(time.Second*10, t)
			testcase.nrc.advertiseExternalIPs()

			watchEvents := waitForBGPWatchEventWithTimeout(time.Second*10, len(testcase.watchEvents), w, t)
			for _, watchEvent := range watchEvents {
				for _, path := range watchEvent.PathList {
					if _, ok := testcase.watchEvents[path.GetNlri().String()]; ok {
						continue
					} else {
						t.Errorf("got unexpected path: %v", path.GetNlri().String())
					}
				}
			}
		})
	}
}

func Test_advertiseRoute(t *testing.T) {
	testcases := []struct {
		name        string
		nrc         *NetworkRoutingController
		envNodeName string
		node        *v1core.Node
		// the key is the subnet from the watch event
		watchEvents map[string]bool
		err         error
	}{
		{
			"add bgp path for pod cidr using NODE_NAME",
			&NetworkRoutingController{
				bgpServer: gobgp.NewBgpServer(),
			},
			"node-1",
			&v1core.Node{
				ObjectMeta: metav1.ObjectMeta{
					Name: "node-1",
				},
				Spec: v1core.NodeSpec{
					PodCIDR: "172.20.0.0/24",
				},
			},
			map[string]bool{
				"172.20.0.0/24": true,
			},
			nil,
		},
		{
			"add bgp path for pod cidr using hostname override",
			&NetworkRoutingController{
				bgpServer:        gobgp.NewBgpServer(),
				hostnameOverride: "node-1",
			},
			"",
			&v1core.Node{
				ObjectMeta: metav1.ObjectMeta{
					Name: "node-1",
				},
				Spec: v1core.NodeSpec{
					PodCIDR: "172.20.0.0/24",
				},
			},
			map[string]bool{
				"172.20.0.0/24": true,
			},
			nil,
		},
		{
			"add bgp path for pod cidr without NODE_NAME or hostname override",
			&NetworkRoutingController{
				bgpServer: gobgp.NewBgpServer(),
			},
			"",
			&v1core.Node{
				ObjectMeta: metav1.ObjectMeta{
					Name: "node-1",
				},
				Spec: v1core.NodeSpec{
					PodCIDR: "172.20.0.0/24",
				},
			},
			map[string]bool{},
			errors.New("Failed to get pod CIDR allocated for the node due to: Failed to identify the node by NODE_NAME, hostname or --hostname-override"),
		},
		{
			"node does not have pod cidr set",
			&NetworkRoutingController{
				bgpServer: gobgp.NewBgpServer(),
			},
			"node-1",
			&v1core.Node{
				ObjectMeta: metav1.ObjectMeta{
					Name: "node-1",
				},
				Spec: v1core.NodeSpec{
					PodCIDR: "",
				},
			},
			map[string]bool{},
			errors.New("node.Spec.PodCIDR not set for node: node-1"),
		},
	}

	for _, testcase := range testcases {
		t.Run(testcase.name, func(t *testing.T) {
			go testcase.nrc.bgpServer.Serve()
			err := testcase.nrc.bgpServer.Start(&config.Global{
				Config: config.GlobalConfig{
					As:       1,
					RouterId: "10.0.0.0",
					Port:     10000,
				},
			})
			if err != nil {
				t.Fatalf("failed to start BGP server: %v", err)
			}
			defer testcase.nrc.bgpServer.Stop()
			w := testcase.nrc.bgpServer.Watch(gobgp.WatchBestPath(false))

			clientset := fake.NewSimpleClientset()
			_, err = clientset.CoreV1().Nodes().Create(testcase.node)
			if err != nil {
				t.Fatalf("failed to create node: %v", err)
			}
			testcase.nrc.clientset = clientset

			os.Setenv("NODE_NAME", testcase.envNodeName)
			defer os.Unsetenv("NODE_NAME")

			err = testcase.nrc.advertiseRoute()
			if !reflect.DeepEqual(err, testcase.err) {
				t.Logf("actual error: %v", err)
				t.Logf("expected error: %v", testcase.err)
				t.Error("did not get expected error")
			}

			watchEvents := waitForBGPWatchEventWithTimeout(time.Second*10, len(testcase.watchEvents), w, t)
			for _, watchEvent := range watchEvents {
				for _, path := range watchEvent.PathList {
					if _, ok := testcase.watchEvents[path.GetNlri().String()]; ok {
						continue
					} else {
						t.Errorf("got unexpected path: %v", path.GetNlri().String())
					}
				}
			}
		})
	}
}

func Test_OnNodeUpdate(t *testing.T) {
	testcases := []struct {
		name        string
		nrc         *NetworkRoutingController
		nodeEvents  []*watchers.NodeUpdate
		activeNodes map[string]bool
	}{
		{
			"node add event",
			&NetworkRoutingController{
				activeNodes:          make(map[string]bool),
				bgpServer:            gobgp.NewBgpServer(),
				defaultNodeAsnNumber: 1,
				clientset:            fake.NewSimpleClientset(),
			},
			[]*watchers.NodeUpdate{
				{
					Node: &v1core.Node{
						ObjectMeta: metav1.ObjectMeta{
							Name: "node-1",
						},
						Status: v1core.NodeStatus{
							Addresses: []v1core.NodeAddress{
								{
									Type:    v1core.NodeInternalIP,
									Address: "10.0.0.1",
								},
							},
						},
					},
					Op: watchers.ADD,
				},
			},
			map[string]bool{
				"10.0.0.1": true,
			},
		},
		{
			"add multiple nodes",
			&NetworkRoutingController{
				activeNodes:          make(map[string]bool),
				bgpServer:            gobgp.NewBgpServer(),
				defaultNodeAsnNumber: 1,
				clientset:            fake.NewSimpleClientset(),
			},
			[]*watchers.NodeUpdate{
				{
					Node: &v1core.Node{
						ObjectMeta: metav1.ObjectMeta{
							Name: "node-1",
						},
						Status: v1core.NodeStatus{
							Addresses: []v1core.NodeAddress{
								{
									Type:    v1core.NodeInternalIP,
									Address: "10.0.0.1",
								},
							},
						},
					},
					Op: watchers.ADD,
				},
				{
					Node: &v1core.Node{
						ObjectMeta: metav1.ObjectMeta{
							Name: "node-2",
						},
						Status: v1core.NodeStatus{
							Addresses: []v1core.NodeAddress{
								{
									Type:    v1core.NodeExternalIP,
									Address: "1.1.1.1",
								},
							},
						},
					},
					Op: watchers.ADD,
				},
			},
			map[string]bool{
				"10.0.0.1": true,
				"1.1.1.1":  true,
			},
		},
		{
			"add and then delete nodes",
			&NetworkRoutingController{
				activeNodes:          make(map[string]bool),
				bgpServer:            gobgp.NewBgpServer(),
				defaultNodeAsnNumber: 1,
				clientset:            fake.NewSimpleClientset(),
			},
			[]*watchers.NodeUpdate{
				{
					Node: &v1core.Node{
						ObjectMeta: metav1.ObjectMeta{
							Name: "node-1",
						},
						Status: v1core.NodeStatus{
							Addresses: []v1core.NodeAddress{
								{
									Type:    v1core.NodeInternalIP,
									Address: "10.0.0.1",
								},
							},
						},
					},
					Op: watchers.ADD,
				},
				{
					Node: &v1core.Node{
						ObjectMeta: metav1.ObjectMeta{
							Name: "node-1",
						},
						Status: v1core.NodeStatus{
							Addresses: []v1core.NodeAddress{
								{
									Type:    v1core.NodeInternalIP,
									Address: "10.0.0.1",
								},
							},
						},
					},
					Op: watchers.REMOVE,
				},
			},
			map[string]bool{},
		},
	}

	for _, testcase := range testcases {
		t.Run(testcase.name, func(t *testing.T) {
			t.Log(testcase.name)
			go testcase.nrc.bgpServer.Serve()
			err := testcase.nrc.bgpServer.Start(&config.Global{
				Config: config.GlobalConfig{
					As:       1,
					RouterId: "10.0.0.0",
					Port:     10000,
				},
			})
			if err != nil {
				t.Fatalf("failed to start BGP server: %v", err)
			}
			defer testcase.nrc.bgpServer.Stop()

			for _, nodeEvent := range testcase.nodeEvents {
				testcase.nrc.OnNodeUpdate(nodeEvent)
			}

			neighbors := testcase.nrc.bgpServer.GetNeighbor("", false)
			for _, neighbor := range neighbors {
				_, exists := testcase.activeNodes[neighbor.Config.NeighborAddress]
				if !exists {
					t.Errorf("expected neighbor: %v doesn't exist", neighbor.Config.NeighborAddress)
				}
			}

			if !reflect.DeepEqual(testcase.nrc.activeNodes, testcase.activeNodes) {
				t.Logf("actual active nodes: %v", testcase.nrc.activeNodes)
				t.Logf("expected active nodes: %v", testcase.activeNodes)
				t.Errorf("did not get expected activeNodes")
			}
		})
	}
}

func createServices(clientset kubernetes.Interface, svcs []*v1core.Service) error {
	for _, svc := range svcs {
		_, err := clientset.CoreV1().Services("default").Create(svc)
		if err != nil {
			return err
		}
	}

	return nil
}

func waitForListerWithTimeout(timeout time.Duration, t *testing.T) {
	tick := time.Tick(100 * time.Millisecond)
	timeoutCh := time.After(timeout)
	for {
		select {
		case <-timeoutCh:
			t.Fatal("timeout exceeded waiting for service lister to fill cache")
		case <-tick:
			if len(watchers.ServiceWatcher.List()) != 0 {
				return
			}
		}
	}
}

func waitForBGPWatchEventWithTimeout(timeout time.Duration, expectedNumEvents int, w *gobgp.Watcher, t *testing.T) []*gobgp.WatchEventBestPath {
	timeoutCh := time.After(timeout)
	var events []*gobgp.WatchEventBestPath
	for {
		select {
		case <-timeoutCh:
			t.Fatalf("timeout exceeded waiting for %d watch events, got %d", expectedNumEvents, len(events))
		case event := <-w.Event():
			events = append(events, event.(*gobgp.WatchEventBestPath))
		default:
			if len(events) == expectedNumEvents {
				return events
			}
		}
	}
}