/*
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 upgrades

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"net/http"
	"path/filepath"
	"sync"
	"time"

	. "github.com/onsi/ginkgo"
	. "github.com/onsi/gomega"

	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/util/wait"
	"k8s.io/kubernetes/pkg/util/version"
	"k8s.io/kubernetes/test/e2e/framework"
)

const manifestPath = "test/e2e/testing-manifests/statefulset/etcd"

type EtcdUpgradeTest struct {
	ip               string
	successfulWrites int
	ssTester         *framework.StatefulSetTester
}

func (EtcdUpgradeTest) Name() string { return "etcd-upgrade" }

func (EtcdUpgradeTest) Skip(upgCtx UpgradeContext) bool {
	minVersion := version.MustParseSemantic("1.6.0")
	for _, vCtx := range upgCtx.Versions {
		if vCtx.Version.LessThan(minVersion) {
			return true
		}
	}
	return false
}

func kubectlCreate(ns, file string) {
	path := filepath.Join(framework.TestContext.RepoRoot, manifestPath, file)
	framework.RunKubectlOrDie("create", "-f", path, fmt.Sprintf("--namespace=%s", ns))
}

func (t *EtcdUpgradeTest) Setup(f *framework.Framework) {
	ns := f.Namespace.Name
	statefulsetPoll := 30 * time.Second
	statefulsetTimeout := 10 * time.Minute
	t.ssTester = framework.NewStatefulSetTester(f.ClientSet)

	By("Creating a PDB")
	kubectlCreate(ns, "pdb.yaml")

	By("Creating an etcd StatefulSet")
	t.ssTester.CreateStatefulSet(manifestPath, ns)

	By("Creating an etcd--test-server deployment")
	kubectlCreate(ns, "tester.yaml")

	By("Getting the ingress IPs from the services")
	err := wait.PollImmediate(statefulsetPoll, statefulsetTimeout, func() (bool, error) {
		if t.ip = t.getServiceIP(f, ns, "test-server"); t.ip == "" {
			return false, nil
		}
		if _, err := t.listUsers(); err != nil {
			framework.Logf("Service endpoint is up but isn't responding")
			return false, nil
		}
		return true, nil
	})
	Expect(err).NotTo(HaveOccurred())
	framework.Logf("Service endpoint is up")

	By("Adding 2 dummy users")
	Expect(t.addUser("Alice")).NotTo(HaveOccurred())
	Expect(t.addUser("Bob")).NotTo(HaveOccurred())
	t.successfulWrites = 2

	By("Verifying that the users exist")
	users, err := t.listUsers()
	Expect(err).NotTo(HaveOccurred())
	Expect(len(users)).To(Equal(2))
}

func (t *EtcdUpgradeTest) listUsers() ([]string, error) {
	r, err := http.Get(fmt.Sprintf("http://%s:8080/list", t.ip))
	if err != nil {
		return nil, err
	}
	defer r.Body.Close()
	if r.StatusCode != http.StatusOK {
		b, err := ioutil.ReadAll(r.Body)
		if err != nil {
			return nil, err
		}
		return nil, fmt.Errorf(string(b))
	}
	var names []string
	if err := json.NewDecoder(r.Body).Decode(&names); err != nil {
		return nil, err
	}
	return names, nil
}

func (t *EtcdUpgradeTest) addUser(name string) error {
	val := map[string][]string{"name": {name}}
	r, err := http.PostForm(fmt.Sprintf("http://%s:8080/add", t.ip), val)
	if err != nil {
		return err
	}
	defer r.Body.Close()
	if r.StatusCode != http.StatusOK {
		b, err := ioutil.ReadAll(r.Body)
		if err != nil {
			return err
		}
		return fmt.Errorf(string(b))
	}
	return nil
}

func (t *EtcdUpgradeTest) getServiceIP(f *framework.Framework, ns, svcName string) string {
	svc, err := f.ClientSet.CoreV1().Services(ns).Get(svcName, metav1.GetOptions{})
	Expect(err).NotTo(HaveOccurred())
	ingress := svc.Status.LoadBalancer.Ingress
	if len(ingress) == 0 {
		return ""
	}
	return ingress[0].IP
}

func (t *EtcdUpgradeTest) Test(f *framework.Framework, done <-chan struct{}, upgrade UpgradeType) {
	By("Continuously polling the database during upgrade.")
	var (
		success, failures, writeAttempts, lastUserCount int
		mu                                              sync.Mutex
		errors                                          = map[string]int{}
	)
	// Write loop.
	go wait.Until(func() {
		writeAttempts++
		if err := t.addUser(fmt.Sprintf("user-%d", writeAttempts)); err != nil {
			framework.Logf("Unable to add user: %v", err)
			mu.Lock()
			errors[err.Error()]++
			mu.Unlock()
			return
		}
		t.successfulWrites++
	}, 10*time.Millisecond, done)
	// Read loop.
	wait.Until(func() {
		users, err := t.listUsers()
		if err != nil {
			framework.Logf("Could not retrieve users: %v", err)
			failures++
			mu.Lock()
			errors[err.Error()]++
			mu.Unlock()
			return
		}
		success++
		lastUserCount = len(users)
	}, 10*time.Millisecond, done)
	framework.Logf("got %d users; want >=%d", lastUserCount, t.successfulWrites)

	Expect(lastUserCount >= t.successfulWrites).To(BeTrue())
	ratio := float64(success) / float64(success+failures)
	framework.Logf("Successful gets %d/%d=%v", success, success+failures, ratio)
	ratio = float64(t.successfulWrites) / float64(writeAttempts)
	framework.Logf("Successful writes %d/%d=%v", t.successfulWrites, writeAttempts, ratio)
	framework.Logf("Errors: %v", errors)
	// TODO(maisem): tweak this value once we have a few test runs.
	Expect(ratio > 0.75).To(BeTrue())
}

// Teardown does one final check of the data's availability.
func (t *EtcdUpgradeTest) Teardown(f *framework.Framework) {
	users, err := t.listUsers()
	Expect(err).NotTo(HaveOccurred())
	Expect(len(users) >= t.successfulWrites).To(BeTrue())
}