/*
Copyright 2019 The KubeSphere 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 monitoring

import (
	"context"
	"fmt"
	"math"
	"strings"
	"time"

	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/labels"
	"k8s.io/apimachinery/pkg/selection"
	"k8s.io/client-go/kubernetes"
	"k8s.io/klog"
	"kubesphere.io/kubesphere/pkg/apis/iam/v1alpha2"
	"kubesphere.io/kubesphere/pkg/apiserver/query"
	ksinformers "kubesphere.io/kubesphere/pkg/client/informers/externalversions"
	"kubesphere.io/kubesphere/pkg/constants"
	"kubesphere.io/kubesphere/pkg/informers"
	"kubesphere.io/kubesphere/pkg/models/monitoring/expressions"
	"kubesphere.io/kubesphere/pkg/models/openpitrix"
	resourcev1alpha3 "kubesphere.io/kubesphere/pkg/models/resources/v1alpha3/resource"
	"kubesphere.io/kubesphere/pkg/server/errors"
	"kubesphere.io/kubesphere/pkg/server/params"
	"kubesphere.io/kubesphere/pkg/simple/client/monitoring"
	opclient "kubesphere.io/kubesphere/pkg/simple/client/openpitrix"
	"sigs.k8s.io/application/api/v1beta1"
	appv1beta1 "sigs.k8s.io/application/api/v1beta1"
)

type MonitoringOperator interface {
	GetMetric(expr, namespace string, time time.Time) (monitoring.Metric, error)
	GetMetricOverTime(expr, namespace string, start, end time.Time, step time.Duration) (monitoring.Metric, error)
	GetNamedMetrics(metrics []string, time time.Time, opt monitoring.QueryOption) Metrics
	GetNamedMetricsOverTime(metrics []string, start, end time.Time, step time.Duration, opt monitoring.QueryOption) Metrics
	GetMetadata(namespace string) Metadata
	GetMetricLabelSet(metric, namespace string, start, end time.Time) MetricLabelSet

	// TODO: expose KubeSphere self metrics in Prometheus format
	GetKubeSphereStats() Metrics
	GetWorkspaceStats(workspace string) Metrics

	// meter
	GetNamedMetersOverTime(metrics []string, start, end time.Time, step time.Duration, opt monitoring.QueryOption) (Metrics, error)
	GetNamedMeters(metrics []string, time time.Time, opt monitoring.QueryOption) (Metrics, error)
	GetAppComponentsMap(ns string, apps []string) map[string][]string
	GetSerivePodsMap(ns string, services []string) map[string][]string
}

type monitoringOperator struct {
	prometheus     monitoring.Interface
	metricsserver  monitoring.Interface
	k8s            kubernetes.Interface
	ks             ksinformers.SharedInformerFactory
	op             openpitrix.Interface
	resourceGetter *resourcev1alpha3.ResourceGetter
}

func NewMonitoringOperator(monitoringClient monitoring.Interface, metricsClient monitoring.Interface, k8s kubernetes.Interface, factory informers.InformerFactory, opClient opclient.Client, resourceGetter *resourcev1alpha3.ResourceGetter) MonitoringOperator {
	return &monitoringOperator{
		prometheus:     monitoringClient,
		metricsserver:  metricsClient,
		k8s:            k8s,
		ks:             factory.KubeSphereSharedInformerFactory(),
		op:             openpitrix.NewOpenpitrixOperator(factory.KubernetesSharedInformerFactory(), opClient),
		resourceGetter: resourceGetter,
	}
}

func (mo monitoringOperator) GetMetric(expr, namespace string, time time.Time) (monitoring.Metric, error) {
	if namespace != "" {
		// Different monitoring backend implementations have different ways to enforce namespace isolation.
		// Each implementation should register itself to `ReplaceNamespaceFns` during init().
		// We hard code "prometheus" here because we only support this datasource so far.
		// In the future, maybe the value should be returned from a method like `mo.c.GetMonitoringServiceName()`.
		var err error
		expr, err = expressions.ReplaceNamespaceFns["prometheus"](expr, namespace)
		if err != nil {
			return monitoring.Metric{}, err
		}
	}
	return mo.prometheus.GetMetric(expr, time), nil
}

func (mo monitoringOperator) GetMetricOverTime(expr, namespace string, start, end time.Time, step time.Duration) (monitoring.Metric, error) {
	if namespace != "" {
		// Different monitoring backend implementations have different ways to enforce namespace isolation.
		// Each implementation should register itself to `ReplaceNamespaceFns` during init().
		// We hard code "prometheus" here because we only support this datasource so far.
		// In the future, maybe the value should be returned from a method like `mo.c.GetMonitoringServiceName()`.
		var err error
		expr, err = expressions.ReplaceNamespaceFns["prometheus"](expr, namespace)
		if err != nil {
			return monitoring.Metric{}, err
		}
	}
	return mo.prometheus.GetMetricOverTime(expr, start, end, step), nil
}

func (mo monitoringOperator) GetNamedMetrics(metrics []string, time time.Time, opt monitoring.QueryOption) Metrics {
	ress := mo.prometheus.GetNamedMetrics(metrics, time, opt)

	if mo.metricsserver != nil {
		mr := mo.metricsserver.GetNamedMetrics(metrics, time, opt)

		//Merge edge node metrics data
		edgeMetrics := make(map[string]monitoring.MetricData)
		for _, metric := range mr {
			edgeMetrics[metric.MetricName] = metric.MetricData
		}

		for i, metric := range ress {
			if val, ok := edgeMetrics[metric.MetricName]; ok {
				ress[i].MetricData.MetricValues = append(ress[i].MetricData.MetricValues, val.MetricValues...)
			}
		}
	}

	return Metrics{Results: ress}
}

func (mo monitoringOperator) GetNamedMetricsOverTime(metrics []string, start, end time.Time, step time.Duration, opt monitoring.QueryOption) Metrics {
	ress := mo.prometheus.GetNamedMetricsOverTime(metrics, start, end, step, opt)

	if mo.metricsserver != nil {
		mr := mo.metricsserver.GetNamedMetricsOverTime(metrics, start, end, step, opt)

		//Merge edge node metrics data
		edgeMetrics := make(map[string]monitoring.MetricData)
		for _, metric := range mr {
			edgeMetrics[metric.MetricName] = metric.MetricData
		}

		for i, metric := range ress {
			if val, ok := edgeMetrics[metric.MetricName]; ok {
				ress[i].MetricData.MetricValues = append(ress[i].MetricData.MetricValues, val.MetricValues...)
			}
		}
	}

	return Metrics{Results: ress}
}

func (mo monitoringOperator) GetMetadata(namespace string) Metadata {
	data := mo.prometheus.GetMetadata(namespace)
	return Metadata{Data: data}
}

func (mo monitoringOperator) GetMetricLabelSet(metric, namespace string, start, end time.Time) MetricLabelSet {
	var expr = metric
	var err error
	if namespace != "" {
		// Different monitoring backend implementations have different ways to enforce namespace isolation.
		// Each implementation should register itself to `ReplaceNamespaceFns` during init().
		// We hard code "prometheus" here because we only support this datasource so far.
		// In the future, maybe the value should be returned from a method like `mo.c.GetMonitoringServiceName()`.
		expr, err = expressions.ReplaceNamespaceFns["prometheus"](metric, namespace)
		if err != nil {
			klog.Error(err)
			return MetricLabelSet{}
		}
	}
	data := mo.prometheus.GetMetricLabelSet(expr, start, end)
	return MetricLabelSet{Data: data}
}

func (mo monitoringOperator) GetKubeSphereStats() Metrics {
	var res Metrics
	now := float64(time.Now().Unix())

	clusterList, err := mo.ks.Cluster().V1alpha1().Clusters().Lister().List(labels.Everything())
	clusterTotal := len(clusterList)
	if clusterTotal == 0 {
		clusterTotal = 1
	}
	if err != nil {
		res.Results = append(res.Results, monitoring.Metric{
			MetricName: KubeSphereClusterCount,
			Error:      err.Error(),
		})
	} else {
		res.Results = append(res.Results, monitoring.Metric{
			MetricName: KubeSphereClusterCount,
			MetricData: monitoring.MetricData{
				MetricType: monitoring.MetricTypeVector,
				MetricValues: []monitoring.MetricValue{
					{
						Sample: &monitoring.Point{now, float64(clusterTotal)},
					},
				},
			},
		})
	}

	wkList, err := mo.ks.Tenant().V1alpha2().WorkspaceTemplates().Lister().List(labels.Everything())
	if err != nil {
		res.Results = append(res.Results, monitoring.Metric{
			MetricName: KubeSphereWorkspaceCount,
			Error:      err.Error(),
		})
	} else {
		res.Results = append(res.Results, monitoring.Metric{
			MetricName: KubeSphereWorkspaceCount,
			MetricData: monitoring.MetricData{
				MetricType: monitoring.MetricTypeVector,
				MetricValues: []monitoring.MetricValue{
					{
						Sample: &monitoring.Point{now, float64(len(wkList))},
					},
				},
			},
		})
	}

	usrList, err := mo.ks.Iam().V1alpha2().Users().Lister().List(labels.Everything())
	if err != nil {
		res.Results = append(res.Results, monitoring.Metric{
			MetricName: KubeSphereUserCount,
			Error:      err.Error(),
		})
	} else {
		res.Results = append(res.Results, monitoring.Metric{
			MetricName: KubeSphereUserCount,
			MetricData: monitoring.MetricData{
				MetricType: monitoring.MetricTypeVector,
				MetricValues: []monitoring.MetricValue{
					{
						Sample: &monitoring.Point{now, float64(len(usrList))},
					},
				},
			},
		})
	}

	cond := &params.Conditions{
		Match: map[string]string{
			openpitrix.Status: openpitrix.StatusActive,
			openpitrix.RepoId: openpitrix.BuiltinRepoId,
		},
	}
	if mo.op != nil {
		tmpl, err := mo.op.ListApps(cond, "", false, 0, 0)
		if err != nil {
			res.Results = append(res.Results, monitoring.Metric{
				MetricName: KubeSphereAppTmplCount,
				Error:      err.Error(),
			})
		} else {
			res.Results = append(res.Results, monitoring.Metric{
				MetricName: KubeSphereAppTmplCount,
				MetricData: monitoring.MetricData{
					MetricType: monitoring.MetricTypeVector,
					MetricValues: []monitoring.MetricValue{
						{
							Sample: &monitoring.Point{now, float64(tmpl.TotalCount)},
						},
					},
				},
			})
		}
	}

	return res
}

func (mo monitoringOperator) GetWorkspaceStats(workspace string) Metrics {
	var res Metrics
	now := float64(time.Now().Unix())

	selector := labels.SelectorFromSet(labels.Set{constants.WorkspaceLabelKey: workspace})
	opt := metav1.ListOptions{LabelSelector: selector.String()}

	nsList, err := mo.k8s.CoreV1().Namespaces().List(context.Background(), opt)
	if err != nil {
		res.Results = append(res.Results, monitoring.Metric{
			MetricName: WorkspaceNamespaceCount,
			Error:      err.Error(),
		})
	} else {
		res.Results = append(res.Results, monitoring.Metric{
			MetricName: WorkspaceNamespaceCount,
			MetricData: monitoring.MetricData{
				MetricType: monitoring.MetricTypeVector,
				MetricValues: []monitoring.MetricValue{
					{
						Sample: &monitoring.Point{now, float64(len(nsList.Items))},
					},
				},
			},
		})
	}

	devopsList, err := mo.ks.Devops().V1alpha3().DevOpsProjects().Lister().List(selector)
	if err != nil {
		res.Results = append(res.Results, monitoring.Metric{
			MetricName: WorkspaceDevopsCount,
			Error:      err.Error(),
		})
	} else {
		res.Results = append(res.Results, monitoring.Metric{
			MetricName: WorkspaceDevopsCount,
			MetricData: monitoring.MetricData{
				MetricType: monitoring.MetricTypeVector,
				MetricValues: []monitoring.MetricValue{
					{
						Sample: &monitoring.Point{now, float64(len(devopsList))},
					},
				},
			},
		})
	}

	r, _ := labels.NewRequirement(v1alpha2.UserReferenceLabel, selection.Exists, nil)
	memberSelector := selector.DeepCopySelector().Add(*r)
	memberList, err := mo.ks.Iam().V1alpha2().WorkspaceRoleBindings().Lister().List(memberSelector)
	if err != nil {
		res.Results = append(res.Results, monitoring.Metric{
			MetricName: WorkspaceMemberCount,
			Error:      err.Error(),
		})
	} else {
		res.Results = append(res.Results, monitoring.Metric{
			MetricName: WorkspaceMemberCount,
			MetricData: monitoring.MetricData{
				MetricType: monitoring.MetricTypeVector,
				MetricValues: []monitoring.MetricValue{
					{
						Sample: &monitoring.Point{now, float64(len(memberList))},
					},
				},
			},
		})
	}

	roleList, err := mo.ks.Iam().V1alpha2().WorkspaceRoles().Lister().List(selector)
	if err != nil {
		res.Results = append(res.Results, monitoring.Metric{
			MetricName: WorkspaceRoleCount,
			Error:      err.Error(),
		})
	} else {
		res.Results = append(res.Results, monitoring.Metric{
			MetricName: WorkspaceRoleCount,
			MetricData: monitoring.MetricData{
				MetricType: monitoring.MetricTypeVector,
				MetricValues: []monitoring.MetricValue{
					{
						Sample: &monitoring.Point{now, float64(len(roleList))},
					},
				},
			},
		})
	}

	return res
}

/*
	meter related methods
*/

func (mo monitoringOperator) getNamedMetersWithHourInterval(meters []string, t time.Time, opt monitoring.QueryOption) Metrics {

	var opts []monitoring.QueryOption

	opts = append(opts, opt)
	opts = append(opts, monitoring.MeterOption{
		Step: 1 * time.Hour,
	})

	ress := mo.prometheus.GetNamedMeters(meters, t, opts)

	return Metrics{Results: ress}
}

func generateScalingFactorMap(step time.Duration) map[string]float64 {
	scalingMap := make(map[string]float64)

	for k := range MeterResourceMap {
		scalingMap[k] = step.Hours()
	}
	return scalingMap
}

func (mo monitoringOperator) GetNamedMetersOverTime(meters []string, start, end time.Time, step time.Duration, opt monitoring.QueryOption) (metrics Metrics, err error) {

	if step.Hours() < 1 {
		klog.Warning("step should be longer than one hour")
		step = 1 * time.Hour
	}
	if end.Sub(start).Hours() > 30*24 {
		if step.Hours() < 24 {
			err = errors.New("step should be larger than 24 hours")
			return
		}
	}
	if math.Mod(step.Hours(), 1.0) > 0 {
		err = errors.New("step should be integer hours")
		return
	}

	// query time range: (start, end], so here we need to exclude start itself.
	if start.Add(step).After(end) {
		start = end
	} else {
		start = start.Add(step)
	}

	var opts []monitoring.QueryOption

	opts = append(opts, opt)
	opts = append(opts, monitoring.MeterOption{
		Start: start,
		End:   end,
		Step:  step,
	})

	ress := mo.prometheus.GetNamedMetersOverTime(meters, start, end, step, opts)
	sMap := generateScalingFactorMap(step)

	for i, _ := range ress {
		ress[i].MetricData = updateMetricStatData(ress[i], sMap)
	}

	return Metrics{Results: ress}, nil
}

func (mo monitoringOperator) GetNamedMeters(meters []string, time time.Time, opt monitoring.QueryOption) (Metrics, error) {

	metersPerHour := mo.getNamedMetersWithHourInterval(meters, time, opt)

	for metricIndex, _ := range metersPerHour.Results {

		res := metersPerHour.Results[metricIndex]

		metersPerHour.Results[metricIndex].MetricData = updateMetricStatData(res, nil)
	}

	return metersPerHour, nil
}

func (mo monitoringOperator) GetAppComponentsMap(ns string, apps []string) map[string][]string {

	componentsMap := make(map[string][]string)
	applicationList := []*appv1beta1.Application{}

	result, err := mo.resourceGetter.List("applications", ns, query.New())
	if err != nil {
		klog.Error(err)
		return nil
	}

	for _, obj := range result.Items {
		app, ok := obj.(*appv1beta1.Application)
		if !ok {
			continue
		}

		applicationList = append(applicationList, app)
	}

	getAppFullName := func(appObject *v1beta1.Application) (name string) {
		name = appObject.Labels[constants.ApplicationName]
		if appObject.Labels[constants.ApplicationVersion] != "" {
			name += fmt.Sprintf(":%v", appObject.Labels[constants.ApplicationVersion])
		}
		return
	}

	appFilter := func(appObject *v1beta1.Application) bool {

		for _, app := range apps {
			var applicationName, applicationVersion string
			tmp := strings.Split(app, ":")

			if len(tmp) >= 1 {
				applicationName = tmp[0]
			}
			if len(tmp) == 2 {
				applicationVersion = tmp[1]
			}

			if applicationName != "" && appObject.Labels[constants.ApplicationName] != applicationName {
				return false
			}
			if applicationVersion != "" && appObject.Labels[constants.ApplicationVersion] != applicationVersion {
				return false
			}
			return true
		}

		return true
	}

	for _, appObj := range applicationList {
		if appFilter(appObj) {
			for _, com := range appObj.Status.ComponentList.Objects {
				kind := strings.Title(com.Kind)
				name := com.Name
				componentsMap[getAppFullName((appObj))] = append(componentsMap[getAppFullName(appObj)], kind+":"+name)
			}
		}
	}

	return componentsMap
}

func (mo monitoringOperator) getApplicationPVCs(appObject *v1beta1.Application) []string {

	var pvcList []string

	ns := appObject.Namespace
	for _, com := range appObject.Status.ComponentList.Objects {

		switch strings.Title(com.Kind) {
		case "Deployment":
			deployObj, err := mo.k8s.AppsV1().Deployments(ns).Get(context.Background(), com.Name, metav1.GetOptions{})
			if err != nil {
				klog.Error(err.Error())
				return nil
			}

			for _, vol := range deployObj.Spec.Template.Spec.Volumes {
				pvcList = append(pvcList, vol.PersistentVolumeClaim.ClaimName)
			}
		case "Statefulset":
			stsObj, err := mo.k8s.AppsV1().StatefulSets(ns).Get(context.Background(), com.Name, metav1.GetOptions{})
			if err != nil {
				klog.Error(err.Error())
				return nil
			}
			for _, vol := range stsObj.Spec.Template.Spec.Volumes {
				pvcList = append(pvcList, vol.PersistentVolumeClaim.ClaimName)
			}
		}

	}

	return pvcList

}

func (mo monitoringOperator) GetSerivePodsMap(ns string, services []string) map[string][]string {
	var svcPodsMap = make(map[string][]string)

	for _, svc := range services {
		svcObj, err := mo.k8s.CoreV1().Services(ns).Get(context.Background(), svc, metav1.GetOptions{})
		if err != nil {
			klog.Error(err.Error())
			return svcPodsMap
		}

		svcSelector := svcObj.Spec.Selector
		if len(svcSelector) == 0 {
			return svcPodsMap
		}

		svcLabels := labels.Set{}
		for key, value := range svcSelector {
			svcLabels[key] = value
		}

		selector := labels.SelectorFromSet(svcLabels)
		opt := metav1.ListOptions{LabelSelector: selector.String()}

		podList, err := mo.k8s.CoreV1().Pods(ns).List(context.Background(), opt)
		if err != nil {
			klog.Error(err.Error())
			return svcPodsMap
		}

		for _, pod := range podList.Items {
			svcPodsMap[svc] = append(svcPodsMap[svc], pod.Name)
		}

	}
	return svcPodsMap
}