package jobs

import (
	"fmt"
	apierrors "k8s.io/apimachinery/pkg/api/errors"
	"strings"
	"sync"
	"time"

	"github.com/nirmata/kyverno/pkg/config"
	v1 "k8s.io/api/batch/v1"
	apiv1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/runtime"

	"github.com/go-logr/logr"

	"github.com/nirmata/kyverno/pkg/constant"

	dclient "github.com/nirmata/kyverno/pkg/dclient"
	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
	"k8s.io/apimachinery/pkg/util/wait"
	"k8s.io/client-go/util/workqueue"
)

const workQueueName = "policy-violation-controller"
const workQueueRetryLimit = 3

//Job creates policy report
type Job struct {
	dclient       *dclient.Client
	log           logr.Logger
	queue         workqueue.RateLimitingInterface
	dataStore     *dataStore
	configHandler config.Interface
	mux           sync.Mutex
}

// Job Info Define Job Type
type JobInfo struct {
	JobType string
	JobData string
}

func (i JobInfo) toKey() string {
	return fmt.Sprintf("kyverno-%v", i.JobType)
}

//NewDataStore returns an instance of data store
func newDataStore() *dataStore {
	ds := dataStore{
		data: make(map[string]JobInfo),
	}
	return &ds
}

type dataStore struct {
	data map[string]JobInfo
	mu   sync.RWMutex
}

func (ds *dataStore) add(keyHash string, info JobInfo) {
	ds.mu.Lock()
	defer ds.mu.Unlock()
	// queue the key hash
	ds.data[keyHash] = info
}

func (ds *dataStore) lookup(keyHash string) JobInfo {
	ds.mu.RLock()
	defer ds.mu.RUnlock()
	return ds.data[keyHash]
}

func (ds *dataStore) delete(keyHash string) {
	ds.mu.Lock()
	defer ds.mu.Unlock()
	delete(ds.data, keyHash)
}

// make the struct hashable

//JobsInterface provides API to create PVs
type JobsInterface interface {
	Add(infos ...JobInfo)
}

// NewJobsJob returns a new instance of policy violation generator
func NewJobsJob(dclient *dclient.Client,
	configHandler config.Interface,
	log logr.Logger) *Job {
	gen := Job{
		dclient:       dclient,
		queue:         workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), workQueueName),
		dataStore:     newDataStore(),
		configHandler: configHandler,
		log:           log,
	}
	go func(configHandler config.Interface) {
		for k := range time.Tick(time.Duration(configHandler.GetBackgroundSync()) * time.Second) {
			gen.log.V(2).Info("Background Sync sync at ", "time", k.String())
			var wg sync.WaitGroup
			wg.Add(3)
			go gen.syncKyverno(&wg, "Helm", "SYNC","")
			go gen.syncKyverno(&wg, "Namespace", "SYNC","")
			go gen.syncKyverno(&wg, "Cluster", "SYNC","")
			wg.Wait()
		}
	}(configHandler)
	return &gen
}

func (j *Job) enqueue(info JobInfo) {
	// add to data map
	keyHash := info.toKey()
	// add to
	// queue the key hash

	j.dataStore.add(keyHash, info)
	j.queue.Add(keyHash)
}

//Add queues a policy violation create request
func (j *Job) Add(infos ...JobInfo) {
	for _, info := range infos {
		j.enqueue(info)
	}
}

// Run starts the workers
func (j *Job) Run(workers int, stopCh <-chan struct{}) {
	logger := j.log
	defer utilruntime.HandleCrash()
	logger.Info("start")
	defer logger.Info("shutting down")

	for i := 0; i < workers; i++ {
		go wait.Until(j.runWorker, constant.PolicyViolationControllerResync, stopCh)
	}
	<-stopCh
}

func (j *Job) runWorker() {
	for j.processNextWorkItem() {
	}
}

func (j *Job) handleErr(err error, key interface{}) {
	logger := j.log
	if err == nil {
		j.queue.Forget(key)
		return
	}

	// retires requests if there is error
	if j.queue.NumRequeues(key) < workQueueRetryLimit {
		logger.Error(err, "failed to sync policy violation", "key", key)
		// Re-enqueue the key rate limited. Based on the rate limiter on the
		// queue and the re-enqueue history, the key will be processed later again.
		j.queue.AddRateLimited(key)
		return
	}
	j.queue.Forget(key)
	// remove from data store
	if keyHash, ok := key.(string); ok {
		j.dataStore.delete(keyHash)
	}
	logger.Error(err, "dropping key out of the queue", "key", key)
}

func (j *Job) processNextWorkItem() bool {
	logger := j.log
	obj, shutdown := j.queue.Get()
	if shutdown {
		return false
	}

	err := func(obj interface{}) error {
		defer j.queue.Done(obj)
		var keyHash string
		var ok bool

		if keyHash, ok = obj.(string); !ok {
			j.queue.Forget(obj)
			logger.Info("incorrect type; expecting type 'string'", "obj", obj)
			return nil
		}

		// lookup data store
		info := j.dataStore.lookup(keyHash)

		err := j.syncHandler(info)
		j.handleErr(err, obj)
		return nil
	}(obj)

	if err != nil {
		logger.Error(err, "failed to process item")
		return true
	}

	return true
}

func (j *Job) syncHandler(info JobInfo) error {
	defer func() {
		j.mux.Unlock()
	}()
	j.mux.Lock()
	var wg sync.WaitGroup
	if info.JobType == "POLICYSYNC" {
		wg.Add(3)
		go j.syncKyverno(&wg, "Helm", "SYNC",info.JobData)
		go j.syncKyverno(&wg, "Namespace", "SYNC",info.JobData)
		go j.syncKyverno(&wg, "Cluster", "SYNC",info.JobData)
	}else if info.JobType == "CONFIGMAP" {
		if info.JobData != "" {
			str := strings.Split(info.JobData,",")
			wg.Add(len(str))
			for _,scope := range str {
				go j.syncKyverno(&wg, scope, "CONFIGMAP","")
			}
		}
	}
	return nil
}

func (j *Job) syncKyverno(wg *sync.WaitGroup, jobType, scope,data string) {
	var args []string
	var mode string
	if scope == "SYNC" || scope == "POLICYSYNC" {
		mode = "cli"
	} else {
		mode = "configmap"
	}

	switch jobType {
	case "Helm":
		args = []string{
			"report",
			"helm",
			fmt.Sprintf("--mode=%s", mode),
		}
		break
	case "Namespace":
		args = []string{
			"report",
			"namespace",
			fmt.Sprintf("--mode=%s", mode),
		}
		break
	case "Cluster":
		args = []string{
			"report",
			"cluster",
			fmt.Sprintf("--mode=%s", mode),
		}
		break
	}

	if scope == "POLICYSYNC" && data != "" {
		args = append(args,fmt.Sprintf("-p=%s", data))
	}
	go j.CreateJob(args, jobType, scope, wg)
	wg.Wait()
}

// CreateJob will create Job template for background scan
func (j *Job) CreateJob(args []string, jobType, scope string, wg *sync.WaitGroup) {
	job := &v1.Job{
		ObjectMeta: metav1.ObjectMeta{
			Namespace: config.KubePolicyNamespace,
			Labels : map[string]string{
				"scope" : scope,
				"type" : jobType,
			},
		},
		Spec: v1.JobSpec{
			Template: apiv1.PodTemplateSpec{
				Spec: apiv1.PodSpec{
					Containers: []apiv1.Container{
						{
							Name:            strings.ToLower(fmt.Sprintf("%s-%s", jobType, scope)),
							Image:           config.KyvernoCliImage,
							ImagePullPolicy: "Always",
							Args:            args,
						},
					},
					ServiceAccountName: "kyverno-service-account",
					RestartPolicy:      "OnFailure",
				},
			},
		},
	}
	job.SetGenerateName("kyverno-policyreport-")
	resource, err := j.dclient.CreateResource("", "Job", config.KubePolicyNamespace, job, false)
	if err != nil {
		return
	}
	if err := runtime.DefaultUnstructuredConverter.FromUnstructured(resource.UnstructuredContent(), &job); err != nil {
		j.log.Error(err,"Error in converting job Default Unstructured Converter","job_name",job.GetName())
		return
	}
	deadline := time.Now().Add(100 * time.Second)
	for {
		time.Sleep(20*time.Second)
		resource, err := j.dclient.GetResource("", "Job", config.KubePolicyNamespace, job.GetName())
		if err != nil {
			if apierrors.IsNotFound(err) {
				j.log.Error(err,"job is already deleted","job_name",job.GetName())
				break
			}
			continue
		}
		job := v1.Job{}
		if err := runtime.DefaultUnstructuredConverter.FromUnstructured(resource.UnstructuredContent(), &job); err != nil {
			j.log.Error(err,"Error in converting job Default Unstructured Converter","job_name",job.GetName())
			continue
		}
		if time.Now().After(deadline) {
			if err := j.dclient.DeleteResource("", "Job", config.KubePolicyNamespace, job.GetName(), false); err != nil {
				j.log.Error(err,"Error in deleting jobs","job_name",job.GetName())
				continue
			}
			break
		}
	}
	wg.Done()
}