/*
Copyright 2016 The Kubernetes Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package etcd3

import (
	"context"
	"testing"
	"time"

	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/fields"
	"k8s.io/apimachinery/pkg/labels"
	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/apimachinery/pkg/util/wait"
	"k8s.io/apimachinery/pkg/watch"
	"k8s.io/apiserver/pkg/apis/example"
	"k8s.io/apiserver/pkg/storage"
	utilflowcontrol "k8s.io/apiserver/pkg/util/flowcontrol"
)

func RunTestWatch(ctx context.Context, t *testing.T, store storage.Interface) {
	testWatch(ctx, t, store, false)
	testWatch(ctx, t, store, true)
}

// It tests that
// - first occurrence of objects should notify Add event
// - update should trigger Modified event
// - update that gets filtered should trigger Deleted event
func testWatch(ctx context.Context, t *testing.T, store storage.Interface, recursive bool) {
	podFoo := &example.Pod{ObjectMeta: metav1.ObjectMeta{Name: "foo"}}
	podBar := &example.Pod{ObjectMeta: metav1.ObjectMeta{Name: "bar"}}

	tests := []struct {
		name       string
		key        string
		pred       storage.SelectionPredicate
		watchTests []*testWatchStruct
	}{{
		name:       "create a key",
		key:        "/somekey-1",
		watchTests: []*testWatchStruct{{podFoo, true, watch.Added}},
		pred:       storage.Everything,
	}, {
		name:       "key updated to match predicate",
		key:        "/somekey-3",
		watchTests: []*testWatchStruct{{podFoo, false, ""}, {podBar, true, watch.Added}},
		pred: storage.SelectionPredicate{
			Label: labels.Everything(),
			Field: fields.ParseSelectorOrDie("metadata.name=bar"),
			GetAttrs: func(obj runtime.Object) (labels.Set, fields.Set, error) {
				pod := obj.(*example.Pod)
				return nil, fields.Set{"metadata.name": pod.Name}, nil
			},
		},
	}, {
		name:       "update",
		key:        "/somekey-4",
		watchTests: []*testWatchStruct{{podFoo, true, watch.Added}, {podBar, true, watch.Modified}},
		pred:       storage.Everything,
	}, {
		name:       "delete because of being filtered",
		key:        "/somekey-5",
		watchTests: []*testWatchStruct{{podFoo, true, watch.Added}, {podBar, true, watch.Deleted}},
		pred: storage.SelectionPredicate{
			Label: labels.Everything(),
			Field: fields.ParseSelectorOrDie("metadata.name!=bar"),
			GetAttrs: func(obj runtime.Object) (labels.Set, fields.Set, error) {
				pod := obj.(*example.Pod)
				return nil, fields.Set{"metadata.name": pod.Name}, nil
			},
		},
	}}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			w, err := store.Watch(ctx, tt.key, storage.ListOptions{ResourceVersion: "0", Predicate: tt.pred, Recursive: recursive})
			if err != nil {
				t.Fatalf("Watch failed: %v", err)
			}
			var prevObj *example.Pod
			for _, watchTest := range tt.watchTests {
				out := &example.Pod{}
				key := tt.key
				if recursive {
					key = key + "/item"
				}
				err := store.GuaranteedUpdate(ctx, key, out, true, nil, storage.SimpleUpdate(
					func(runtime.Object) (runtime.Object, error) {
						return watchTest.obj, nil
					}), nil)
				if err != nil {
					t.Fatalf("GuaranteedUpdate failed: %v", err)
				}
				if watchTest.expectEvent {
					expectObj := out
					if watchTest.watchType == watch.Deleted {
						expectObj = prevObj
						expectObj.ResourceVersion = out.ResourceVersion
					}
					testCheckResult(t, watchTest.watchType, w, expectObj)
				}
				prevObj = out
			}
			w.Stop()
			testCheckStop(t, w)
		})
	}
}

func RunTestDeleteTriggerWatch(ctx context.Context, t *testing.T, store storage.Interface) {
	key, storedObj := testPropogateStore(ctx, t, store, &example.Pod{ObjectMeta: metav1.ObjectMeta{Name: "foo"}})
	w, err := store.Watch(ctx, key, storage.ListOptions{ResourceVersion: storedObj.ResourceVersion, Predicate: storage.Everything})
	if err != nil {
		t.Fatalf("Watch failed: %v", err)
	}
	if err := store.Delete(ctx, key, &example.Pod{}, nil, storage.ValidateAllObjectFunc, nil); err != nil {
		t.Fatalf("Delete failed: %v", err)
	}
	testCheckEventType(t, watch.Deleted, w)
}

func RunTestWatchFromNoneZero(ctx context.Context, t *testing.T, store storage.Interface) {
	key, storedObj := testPropogateStore(ctx, t, store, &example.Pod{ObjectMeta: metav1.ObjectMeta{Name: "foo"}})

	w, err := store.Watch(ctx, key, storage.ListOptions{ResourceVersion: storedObj.ResourceVersion, Predicate: storage.Everything})
	if err != nil {
		t.Fatalf("Watch failed: %v", err)
	}
	out := &example.Pod{}
	store.GuaranteedUpdate(ctx, key, out, true, nil, storage.SimpleUpdate(
		func(runtime.Object) (runtime.Object, error) {
			return &example.Pod{ObjectMeta: metav1.ObjectMeta{Name: "bar"}}, err
		}), nil)
	testCheckResult(t, watch.Modified, w, out)
}

func RunTestWatchInitializationSignal(ctx context.Context, t *testing.T, store storage.Interface) {
	ctx, _ = context.WithTimeout(ctx, 5*time.Second)
	initSignal := utilflowcontrol.NewInitializationSignal()
	ctx = utilflowcontrol.WithInitializationSignal(ctx, initSignal)

	key, storedObj := testPropogateStore(ctx, t, store, &example.Pod{ObjectMeta: metav1.ObjectMeta{Name: "foo"}})
	_, err := store.Watch(ctx, key, storage.ListOptions{ResourceVersion: storedObj.ResourceVersion, Predicate: storage.Everything})
	if err != nil {
		t.Fatalf("Watch failed: %v", err)
	}

	initSignal.Wait()
}

type testWatchStruct struct {
	obj         *example.Pod
	expectEvent bool
	watchType   watch.EventType
}

func testCheckEventType(t *testing.T, expectEventType watch.EventType, w watch.Interface) {
	select {
	case res := <-w.ResultChan():
		if res.Type != expectEventType {
			t.Errorf("event type want=%v, get=%v", expectEventType, res.Type)
		}
	case <-time.After(wait.ForeverTestTimeout):
		t.Errorf("time out after waiting %v on ResultChan", wait.ForeverTestTimeout)
	}
}

func testCheckResult(t *testing.T, expectEventType watch.EventType, w watch.Interface, expectObj *example.Pod) {
	testCheckResultFunc(t, expectEventType, w, func(object runtime.Object) error {
		expectNoDiff(t, "incorrect object", expectObj, object)
		return nil
	})
}

func testCheckResultFunc(t *testing.T, expectEventType watch.EventType, w watch.Interface, check func(object runtime.Object) error) {
	select {
	case res := <-w.ResultChan():
		if res.Type != expectEventType {
			t.Errorf("event type want=%v, get=%v", expectEventType, res.Type)
			return
		}
		if err := check(res.Object); err != nil {
			t.Error(err)
		}
	case <-time.After(wait.ForeverTestTimeout):
		t.Errorf("time out after waiting %v on ResultChan", wait.ForeverTestTimeout)
	}
}

func testCheckStop(t *testing.T, w watch.Interface) {
	select {
	case e, ok := <-w.ResultChan():
		if ok {
			var obj string
			switch e.Object.(type) {
			case *example.Pod:
				obj = e.Object.(*example.Pod).Name
			case *metav1.Status:
				obj = e.Object.(*metav1.Status).Message
			}
			t.Errorf("ResultChan should have been closed. Event: %s. Object: %s", e.Type, obj)
		}
	case <-time.After(wait.ForeverTestTimeout):
		t.Errorf("time out after waiting 1s on ResultChan")
	}
}