/*
Copyright 2015 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 testing

import (
	"bytes"
	"context"
	"fmt"
	"path"
	"reflect"
	"sync"
	"sync/atomic"
	"testing"
	"time"

	"github.com/google/go-cmp/cmp"
	"k8s.io/apimachinery/pkg/api/meta"
	v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"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"
	"k8s.io/apiserver/pkg/storage/value"
)

// CreateObjList will create a list from the array of objects.
func CreateObjList(prefix string, helper storage.Interface, items []runtime.Object) error {
	for i := range items {
		obj := items[i]
		meta, err := meta.Accessor(obj)
		if err != nil {
			return err
		}
		err = helper.Create(context.Background(), path.Join(prefix, meta.GetName()), obj, obj, 0)
		if err != nil {
			return err
		}
		items[i] = obj
	}
	return nil
}

// CreateList will properly create a list using the storage interface.
func CreateList(prefix string, helper storage.Interface, list runtime.Object) error {
	items, err := meta.ExtractList(list)
	if err != nil {
		return err
	}
	err = CreateObjList(prefix, helper, items)
	if err != nil {
		return err
	}
	return meta.SetList(list, items)
}

// DeepEqualSafePodSpec returns an example.PodSpec safe for deep-equal operations.
func DeepEqualSafePodSpec() example.PodSpec {
	grace := int64(30)
	return example.PodSpec{
		RestartPolicy:                 "Always",
		TerminationGracePeriodSeconds: &grace,
		SchedulerName:                 "default-scheduler",
	}
}

func computePodKey(obj *example.Pod) string {
	return fmt.Sprintf("/pods/%s/%s", obj.Namespace, obj.Name)
}

// testPropagateStore helps propagates store with objects, automates key generation, and returns
// keys and stored objects.
func testPropagateStore(ctx context.Context, t *testing.T, store storage.Interface, obj *example.Pod) (string, *example.Pod) {
	// Setup store with a key and grab the output for returning.
	key := computePodKey(obj)

	// Setup store with the specified key and grab the output for returning.
	err := store.Delete(ctx, key, &example.Pod{}, nil, storage.ValidateAllObjectFunc, nil)
	if err != nil && !storage.IsNotFound(err) {
		t.Fatalf("Cleanup failed: %v", err)
	}
	setOutput := &example.Pod{}
	if err := store.Create(ctx, key, obj, setOutput, 0); err != nil {
		t.Fatalf("Set failed: %v", err)
	}
	return key, setOutput
}

func expectNoDiff(t *testing.T, msg string, expected, actual interface{}) {
	t.Helper()
	if !reflect.DeepEqual(expected, actual) {
		if diff := cmp.Diff(expected, actual); diff != "" {
			t.Errorf("%s: %s", msg, diff)
		} else {
			t.Errorf("%s:\nexpected: %#v\ngot: %#v", msg, expected, actual)
		}
	}
}

func ExpectContains(t *testing.T, msg string, expectedList []interface{}, got interface{}) {
	t.Helper()
	for _, expected := range expectedList {
		if reflect.DeepEqual(expected, got) {
			return
		}
	}
	if len(expectedList) == 0 {
		t.Errorf("%s: empty expectedList", msg)
		return
	}
	if diff := cmp.Diff(expectedList[0], got); diff != "" {
		t.Errorf("%s: differs from all items, with first: %s", msg, diff)
	} else {
		t.Errorf("%s: differs from all items, first: %#v\ngot: %#v", msg, expectedList[0], got)
	}
}

const dummyPrefix = "adapter"

func encodeContinueOrDie(key string, resourceVersion int64) string {
	token, err := storage.EncodeContinue(dummyPrefix+key, dummyPrefix, resourceVersion)
	if err != nil {
		panic(err)
	}
	return token
}

func testCheckEventType(t *testing.T, w watch.Interface, expectEventType watch.EventType) {
	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, w watch.Interface, expectEvent watch.Event) {
	testCheckResultFunc(t, w, func(actualEvent watch.Event) {
		expectNoDiff(t, "incorrect event", expectEvent, actualEvent)
	})
}

func testCheckResultFunc(t *testing.T, w watch.Interface, check func(actualEvent watch.Event)) {
	select {
	case res := <-w.ResultChan():
		obj := res.Object
		if co, ok := obj.(runtime.CacheableObject); ok {
			res.Object = co.GetObject()
		}
		check(res)
	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 *v1.Status:
				obj = e.Object.(*v1.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")
	}
}

func testCheckResultsInStrictOrder(t *testing.T, w watch.Interface, expectedEvents []watch.Event) {
	for _, expectedEvent := range expectedEvents {
		testCheckResult(t, w, expectedEvent)
	}
}

func testCheckResultsInRandomOrder(t *testing.T, w watch.Interface, expectedEvents []watch.Event) {
	for range expectedEvents {
		testCheckResultFunc(t, w, func(actualEvent watch.Event) {
			ExpectContains(t, "unexpected event", toInterfaceSlice(expectedEvents), actualEvent)
		})
	}
}

func testCheckNoMoreResults(t *testing.T, w watch.Interface) {
	select {
	case e := <-w.ResultChan():
		t.Errorf("Unexpected: %#v event received, expected no events", e)
	case <-time.After(time.Second):
		return
	}
}

func toInterfaceSlice[T any](s []T) []interface{} {
	result := make([]interface{}, len(s))
	for i, v := range s {
		result[i] = v
	}
	return result
}

// resourceVersionNotOlderThan returns a function to validate resource versions. Resource versions
// referring to points in logical time before the sentinel generate an error. All logical times as
// new as the sentinel or newer generate no error.
func resourceVersionNotOlderThan(sentinel string) func(string) error {
	return func(resourceVersion string) error {
		objectVersioner := storage.APIObjectVersioner{}
		actualRV, err := objectVersioner.ParseResourceVersion(resourceVersion)
		if err != nil {
			return err
		}
		expectedRV, err := objectVersioner.ParseResourceVersion(sentinel)
		if err != nil {
			return err
		}
		if actualRV < expectedRV {
			return fmt.Errorf("expected a resourceVersion no smaller than than %d, but got %d", expectedRV, actualRV)
		}
		return nil
	}
}

// StorageInjectingListErrors injects a dummy error for first N GetList calls.
type StorageInjectingListErrors struct {
	storage.Interface

	lock   sync.Mutex
	Errors int
}

func (s *StorageInjectingListErrors) GetList(ctx context.Context, key string, opts storage.ListOptions, listObj runtime.Object) error {
	err := func() error {
		s.lock.Lock()
		defer s.lock.Unlock()
		if s.Errors > 0 {
			s.Errors--
			return fmt.Errorf("injected error")
		}
		return nil
	}()
	if err != nil {
		return err
	}
	return s.Interface.GetList(ctx, key, opts, listObj)
}

func (s *StorageInjectingListErrors) ErrorsConsumed() (bool, error) {
	s.lock.Lock()
	defer s.lock.Unlock()
	return s.Errors == 0, nil
}

// PrefixTransformer adds and verifies that all data has the correct prefix on its way in and out.
type PrefixTransformer struct {
	prefix []byte
	stale  bool
	err    error
	reads  uint64
}

func NewPrefixTransformer(prefix []byte, stale bool) *PrefixTransformer {
	return &PrefixTransformer{
		prefix: prefix,
		stale:  stale,
	}
}

func (p *PrefixTransformer) TransformFromStorage(ctx context.Context, data []byte, dataCtx value.Context) ([]byte, bool, error) {
	atomic.AddUint64(&p.reads, 1)
	if dataCtx == nil {
		panic("no context provided")
	}
	if !bytes.HasPrefix(data, p.prefix) {
		return nil, false, fmt.Errorf("value does not have expected prefix %q: %s,", p.prefix, string(data))
	}
	return bytes.TrimPrefix(data, p.prefix), p.stale, p.err
}
func (p *PrefixTransformer) TransformToStorage(ctx context.Context, data []byte, dataCtx value.Context) ([]byte, error) {
	if dataCtx == nil {
		panic("no context provided")
	}
	if len(data) > 0 {
		return append(append([]byte{}, p.prefix...), data...), p.err
	}
	return data, p.err
}

func (p *PrefixTransformer) GetReadsAndReset() uint64 {
	return atomic.SwapUint64(&p.reads, 0)
}

// reproducingTransformer is a custom test-only transformer used purely
// for testing consistency.
// It allows for creating predefined objects on TransformFromStorage operations,
// which allows for precise in time injection of new objects in the middle of
// read operations.
type reproducingTransformer struct {
	wrapped value.Transformer
	store   storage.Interface

	index      uint32
	nextObject func(uint32) (string, *example.Pod)
}

func (rt *reproducingTransformer) TransformFromStorage(ctx context.Context, data []byte, dataCtx value.Context) ([]byte, bool, error) {
	if err := rt.createObject(ctx); err != nil {
		return nil, false, err
	}
	return rt.wrapped.TransformFromStorage(ctx, data, dataCtx)
}

func (rt *reproducingTransformer) TransformToStorage(ctx context.Context, data []byte, dataCtx value.Context) ([]byte, error) {
	return rt.wrapped.TransformToStorage(ctx, data, dataCtx)
}

func (rt *reproducingTransformer) createObject(ctx context.Context) error {
	key, obj := rt.nextObject(atomic.AddUint32(&rt.index, 1))
	out := &example.Pod{}
	return rt.store.Create(ctx, key, obj, out, 0)
}

// failingTransformer is a custom test-only transformer that always returns
// an error on transforming data from storage.
type failingTransformer struct {
}

func (ft *failingTransformer) TransformFromStorage(ctx context.Context, data []byte, dataCtx value.Context) ([]byte, bool, error) {
	return nil, false, fmt.Errorf("failed transformation")
}

func (ft *failingTransformer) TransformToStorage(ctx context.Context, data []byte, dataCtx value.Context) ([]byte, error) {
	return data, nil
}

type sortablePodList []example.Pod

func (s sortablePodList) Len() int {
	return len(s)
}

func (s sortablePodList) Less(i, j int) bool {
	return computePodKey(&s[i]) < computePodKey(&s[j])
}

func (s sortablePodList) Swap(i, j int) {
	s[i], s[j] = s[j], s[i]
}
