/*
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"
	"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"
	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"
	"kubesphere.io/kubesphere/pkg/server/params"
	"kubesphere.io/kubesphere/pkg/simple/client/monitoring"
	opclient "kubesphere.io/kubesphere/pkg/simple/client/openpitrix"
)

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
}

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

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

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
}