/*
Copyright 2017 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 cache

import (
	"fmt"
	"sync"
	"testing"
	"time"

	"k8s.io/api/core/v1"
	"k8s.io/apimachinery/pkg/api/meta"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/util/clock"
	"k8s.io/apimachinery/pkg/util/sets"
	"k8s.io/apimachinery/pkg/util/wait"
	fcache "k8s.io/client-go/tools/cache/testing"
)

type testListener struct {
	lock              sync.RWMutex
	resyncPeriod      time.Duration
	expectedItemNames sets.String
	receivedItemNames []string
	name              string
}

func newTestListener(name string, resyncPeriod time.Duration, expected ...string) *testListener {
	l := &testListener{
		resyncPeriod:      resyncPeriod,
		expectedItemNames: sets.NewString(expected...),
		name:              name,
	}
	return l
}

func (l *testListener) OnAdd(obj interface{}) {
	l.handle(obj)
}

func (l *testListener) OnUpdate(old, new interface{}) {
	l.handle(new)
}

func (l *testListener) OnDelete(obj interface{}) {
}

func (l *testListener) handle(obj interface{}) {
	key, _ := MetaNamespaceKeyFunc(obj)
	fmt.Printf("%s: handle: %v\n", l.name, key)
	l.lock.Lock()
	defer l.lock.Unlock()

	objectMeta, _ := meta.Accessor(obj)
	l.receivedItemNames = append(l.receivedItemNames, objectMeta.GetName())
}

func (l *testListener) ok() bool {
	fmt.Println("polling")
	err := wait.PollImmediate(100*time.Millisecond, 2*time.Second, func() (bool, error) {
		if l.satisfiedExpectations() {
			return true, nil
		}
		return false, nil
	})
	if err != nil {
		return false
	}

	// wait just a bit to allow any unexpected stragglers to come in
	fmt.Println("sleeping")
	time.Sleep(1 * time.Second)
	fmt.Println("final check")
	return l.satisfiedExpectations()
}

func (l *testListener) satisfiedExpectations() bool {
	l.lock.RLock()
	defer l.lock.RUnlock()

	return len(l.receivedItemNames) == l.expectedItemNames.Len() && sets.NewString(l.receivedItemNames...).Equal(l.expectedItemNames)
}

func TestListenerResyncPeriods(t *testing.T) {
	// source simulates an apiserver object endpoint.
	source := fcache.NewFakeControllerSource()
	source.Add(&v1.Pod{ObjectMeta: metav1.ObjectMeta{Name: "pod1"}})
	source.Add(&v1.Pod{ObjectMeta: metav1.ObjectMeta{Name: "pod2"}})

	// create the shared informer and resync every 1s
	informer := NewSharedInformer(source, &v1.Pod{}, 1*time.Second).(*sharedIndexInformer)

	clock := clock.NewFakeClock(time.Now())
	informer.clock = clock
	informer.processor.clock = clock

	// listener 1, never resync
	listener1 := newTestListener("listener1", 0, "pod1", "pod2")
	informer.AddEventHandlerWithResyncPeriod(listener1, listener1.resyncPeriod)

	// listener 2, resync every 2s
	listener2 := newTestListener("listener2", 2*time.Second, "pod1", "pod2")
	informer.AddEventHandlerWithResyncPeriod(listener2, listener2.resyncPeriod)

	// listener 3, resync every 3s
	listener3 := newTestListener("listener3", 3*time.Second, "pod1", "pod2")
	informer.AddEventHandlerWithResyncPeriod(listener3, listener3.resyncPeriod)
	listeners := []*testListener{listener1, listener2, listener3}

	stop := make(chan struct{})
	defer close(stop)

	go informer.Run(stop)

	// ensure all listeners got the initial List
	for _, listener := range listeners {
		if !listener.ok() {
			t.Errorf("%s: expected %v, got %v", listener.name, listener.expectedItemNames, listener.receivedItemNames)
		}
	}

	// reset
	for _, listener := range listeners {
		listener.receivedItemNames = []string{}
	}

	// advance so listener2 gets a resync
	clock.Step(2 * time.Second)

	// make sure listener2 got the resync
	if !listener2.ok() {
		t.Errorf("%s: expected %v, got %v", listener2.name, listener2.expectedItemNames, listener2.receivedItemNames)
	}

	// wait a bit to give errant items a chance to go to 1 and 3
	time.Sleep(1 * time.Second)

	// make sure listeners 1 and 3 got nothing
	if len(listener1.receivedItemNames) != 0 {
		t.Errorf("listener1: should not have resynced (got %d)", len(listener1.receivedItemNames))
	}
	if len(listener3.receivedItemNames) != 0 {
		t.Errorf("listener3: should not have resynced (got %d)", len(listener3.receivedItemNames))
	}

	// reset
	for _, listener := range listeners {
		listener.receivedItemNames = []string{}
	}

	// advance so listener3 gets a resync
	clock.Step(1 * time.Second)

	// make sure listener3 got the resync
	if !listener3.ok() {
		t.Errorf("%s: expected %v, got %v", listener3.name, listener3.expectedItemNames, listener3.receivedItemNames)
	}

	// wait a bit to give errant items a chance to go to 1 and 2
	time.Sleep(1 * time.Second)

	// make sure listeners 1 and 2 got nothing
	if len(listener1.receivedItemNames) != 0 {
		t.Errorf("listener1: should not have resynced (got %d)", len(listener1.receivedItemNames))
	}
	if len(listener2.receivedItemNames) != 0 {
		t.Errorf("listener2: should not have resynced (got %d)", len(listener2.receivedItemNames))
	}
}

func TestResyncCheckPeriod(t *testing.T) {
	// source simulates an apiserver object endpoint.
	source := fcache.NewFakeControllerSource()

	// create the shared informer and resync every 12 hours
	informer := NewSharedInformer(source, &v1.Pod{}, 12*time.Hour).(*sharedIndexInformer)

	clock := clock.NewFakeClock(time.Now())
	informer.clock = clock
	informer.processor.clock = clock

	// listener 1, never resync
	listener1 := newTestListener("listener1", 0)
	informer.AddEventHandlerWithResyncPeriod(listener1, listener1.resyncPeriod)
	if e, a := 12*time.Hour, informer.resyncCheckPeriod; e != a {
		t.Errorf("expected %d, got %d", e, a)
	}
	if e, a := time.Duration(0), informer.processor.listeners[0].resyncPeriod; e != a {
		t.Errorf("expected %d, got %d", e, a)
	}

	// listener 2, resync every minute
	listener2 := newTestListener("listener2", 1*time.Minute)
	informer.AddEventHandlerWithResyncPeriod(listener2, listener2.resyncPeriod)
	if e, a := 1*time.Minute, informer.resyncCheckPeriod; e != a {
		t.Errorf("expected %d, got %d", e, a)
	}
	if e, a := time.Duration(0), informer.processor.listeners[0].resyncPeriod; e != a {
		t.Errorf("expected %d, got %d", e, a)
	}
	if e, a := 1*time.Minute, informer.processor.listeners[1].resyncPeriod; e != a {
		t.Errorf("expected %d, got %d", e, a)
	}

	// listener 3, resync every 55 seconds
	listener3 := newTestListener("listener3", 55*time.Second)
	informer.AddEventHandlerWithResyncPeriod(listener3, listener3.resyncPeriod)
	if e, a := 55*time.Second, informer.resyncCheckPeriod; e != a {
		t.Errorf("expected %d, got %d", e, a)
	}
	if e, a := time.Duration(0), informer.processor.listeners[0].resyncPeriod; e != a {
		t.Errorf("expected %d, got %d", e, a)
	}
	if e, a := 1*time.Minute, informer.processor.listeners[1].resyncPeriod; e != a {
		t.Errorf("expected %d, got %d", e, a)
	}
	if e, a := 55*time.Second, informer.processor.listeners[2].resyncPeriod; e != a {
		t.Errorf("expected %d, got %d", e, a)
	}

	// listener 4, resync every 5 seconds
	listener4 := newTestListener("listener4", 5*time.Second)
	informer.AddEventHandlerWithResyncPeriod(listener4, listener4.resyncPeriod)
	if e, a := 5*time.Second, informer.resyncCheckPeriod; e != a {
		t.Errorf("expected %d, got %d", e, a)
	}
	if e, a := time.Duration(0), informer.processor.listeners[0].resyncPeriod; e != a {
		t.Errorf("expected %d, got %d", e, a)
	}
	if e, a := 1*time.Minute, informer.processor.listeners[1].resyncPeriod; e != a {
		t.Errorf("expected %d, got %d", e, a)
	}
	if e, a := 55*time.Second, informer.processor.listeners[2].resyncPeriod; e != a {
		t.Errorf("expected %d, got %d", e, a)
	}
	if e, a := 5*time.Second, informer.processor.listeners[3].resyncPeriod; e != a {
		t.Errorf("expected %d, got %d", e, a)
	}
}
