package logs_test

import (
	"bytes"
	"context"
	"errors"
	"io"
	"strings"
	"testing"
	"time"

	"git.netflux.io/rob/kubectl-persistent-logger/logs"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	appsv1 "k8s.io/api/apps/v1"
	corev1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/watch"
	testclient "k8s.io/client-go/kubernetes/fake"
	k8stest "k8s.io/client-go/testing"
)

type mockPodWatcher struct{ err error }

func (m *mockPodWatcher) WatchPods(ctx context.Context) error { return m.err }
func (m *mockPodWatcher) Close()                              {}

func mockPodwatcherFunc(err error) logs.PodWatcherFunc {
	return func(logs.KubernetesClient, string, *metav1.LabelSelector, io.Writer) logs.PodWatcherInterface {
		return &mockPodWatcher{err: err}
	}
}

func TestWatcherAllowNonExistent(t *testing.T) {
	clientset := testclient.NewSimpleClientset()

	var buf bytes.Buffer
	client := logs.KubernetesClient{Interface: clientset}
	watcher := logs.NewWatcher("mydeployment", "mycontainer", true, client, mockPodwatcherFunc(nil), &buf)

	err := watcher.Watch(context.Background())
	assert.EqualError(t, err, `deployments.apps "mydeployment" not found`)
}

func TestWatcherPodWatcherError(t *testing.T) {
	deploymentsWatcher := watch.NewFake()
	clientset := testclient.NewSimpleClientset(
		&appsv1.Deployment{ObjectMeta: metav1.ObjectMeta{Name: "mydeployment", Namespace: "default"}},
	)
	clientset.PrependWatchReactor("deployments", k8stest.DefaultWatchReactor(deploymentsWatcher, nil))

	var buf bytes.Buffer
	client := logs.KubernetesClient{Interface: clientset}
	wantErr := errors.New("foo")
	watcher := logs.NewWatcher("mydeployment", "mycontainer", true, client, mockPodwatcherFunc(wantErr), &buf)

	go func() {
		defer deploymentsWatcher.Stop()
		deployment := &appsv1.Deployment{ObjectMeta: metav1.ObjectMeta{Name: "mydeployment", Namespace: "default"}}
		deploymentsWatcher.Add(deployment)
	}()

	err := watcher.Watch(context.Background())
	assert.EqualError(t, err, wantErr.Error())
}

func TestWatcherClosedChannel(t *testing.T) {
	deploymentsWatcher := watch.NewFake()
	clientset := testclient.NewSimpleClientset(
		&appsv1.Deployment{ObjectMeta: metav1.ObjectMeta{Name: "mydeployment", Namespace: "default"}},
	)
	clientset.PrependWatchReactor("deployments", k8stest.DefaultWatchReactor(deploymentsWatcher, nil))

	var buf bytes.Buffer
	client := logs.KubernetesClient{Interface: clientset}
	watcher := logs.NewWatcher("mydeployment", "mycontainer", true, client, nil, &buf)
	go deploymentsWatcher.Stop()

	ctx, cancel := context.WithTimeout(context.Background(), time.Millisecond*500)
	defer cancel()

	err := watcher.Watch(ctx)
	require.Equal(t, context.DeadlineExceeded, err)
	assert.Equal(t, "", buf.String())
}

func TestWatcherWithPodWatcher(t *testing.T) {
	ctx, cancel := context.WithCancel(context.Background())

	deploymentsWatcher := watch.NewFake()
	defer deploymentsWatcher.Stop()
	podsWatcher := watch.NewFake()
	defer podsWatcher.Stop()

	clientset := testclient.NewSimpleClientset()
	clientset.PrependWatchReactor("pods", k8stest.DefaultWatchReactor(podsWatcher, nil))
	clientset.PrependWatchReactor("deployments", k8stest.DefaultWatchReactor(deploymentsWatcher, nil))

	go func() {
		defer cancel()

		deployment := &appsv1.Deployment{ObjectMeta: metav1.ObjectMeta{Name: "mydeployment", Namespace: "default"}}
		deploymentsWatcher.Add(deployment)
		time.Sleep(time.Millisecond * 250)

		pods := []*corev1.Pod{
			{
				ObjectMeta: metav1.ObjectMeta{Name: "foo", Namespace: "default"},
				Status:     corev1.PodStatus{Phase: corev1.PodRunning},
			},
			{
				ObjectMeta: metav1.ObjectMeta{Name: "bar", Namespace: "default"},
				Status:     corev1.PodStatus{Phase: corev1.PodRunning},
			},
			{
				ObjectMeta: metav1.ObjectMeta{Name: "baz", Namespace: "default"},
				Status:     corev1.PodStatus{Phase: corev1.PodPending},
			},
		}
		for _, pod := range pods {
			podsWatcher.Add(pod)
			time.Sleep(time.Millisecond * 250)
		}
	}()

	var buf bytes.Buffer
	client := logs.KubernetesClient{Interface: clientset}
	watcher := logs.NewWatcher("mydeployment", "mycontainer", false, client, logs.NewPodWatcher, &buf)

	err := watcher.Watch(ctx)
	require.EqualError(t, err, context.Canceled.Error())
	assert.ElementsMatch(t, []string{"[foo] fake logs", "[bar] fake logs"}, splitBuf(&buf))
}

func splitBuf(buf *bytes.Buffer) []string {
	return strings.Split(strings.TrimSpace(buf.String()), "\n")
}