package monitor

import (
	"context"
	"encoding/json"
	"fmt"
	"net/http"
	"strings"
	"time"

	"github.com/rancher/norman/api/access"
	"github.com/rancher/norman/httperror"
	"github.com/rancher/norman/parse"
	"github.com/rancher/norman/types"
	"github.com/rancher/norman/types/convert"
	"github.com/rancher/rancher/pkg/clustermanager"
	monitorutil "github.com/rancher/rancher/pkg/monitoring"
	"github.com/rancher/rancher/pkg/ref"
	"github.com/rancher/types/apis/management.cattle.io/v3"
	mgmtclientv3 "github.com/rancher/types/client/management/v3"
	"github.com/rancher/types/config"
	"github.com/rancher/types/config/dialer"
	"github.com/sirupsen/logrus"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/labels"
)

const (
	projectIDAnn = "field.cattle.io/projectId"
)

func NewClusterGraphHandler(dialerFactory dialer.Factory, clustermanager *clustermanager.Manager) *ClusterGraphHandler {
	return &ClusterGraphHandler{
		dialerFactory:  dialerFactory,
		clustermanager: clustermanager,
	}
}

type ClusterGraphHandler struct {
	dialerFactory  dialer.Factory
	clustermanager *clustermanager.Manager
}

func (h *ClusterGraphHandler) QuerySeriesAction(actionName string, action *types.Action, apiContext *types.APIContext) error {
	var queryGraphInput v3.QueryGraphInput
	actionInput, err := parse.ReadBody(apiContext.Request)
	if err != nil {
		return err
	}

	if err = convert.ToObj(actionInput, &queryGraphInput); err != nil {
		return err
	}

	inputParser := newClusterGraphInputParser(queryGraphInput)
	if err = inputParser.parse(); err != nil {
		return err
	}

	clusterName := inputParser.ClusterName
	userContext, err := h.clustermanager.UserContext(clusterName)
	if err != nil {
		return fmt.Errorf("get usercontext failed, %v", err)
	}

	prometheusName, prometheusNamespace := monitorutil.ClusterMonitoringInfo()
	token, err := getAuthToken(userContext, prometheusName, prometheusNamespace)
	if err != nil {
		return err
	}

	reqContext, cancel := context.WithTimeout(context.Background(), prometheusReqTimeout)
	defer cancel()

	svcName, svcNamespace, svcPort := monitorutil.ClusterPrometheusEndpoint()
	prometheusQuery, err := NewPrometheusQuery(reqContext, clusterName, token, svcNamespace, svcName, svcPort, h.dialerFactory, userContext)
	if err != nil {
		return err
	}

	mgmtClient := h.clustermanager.ScaledContext.Management
	nodeLister := mgmtClient.Nodes(metav1.NamespaceAll).Controller().Lister()

	nodeMap, err := getNodeName2InternalIPMap(nodeLister, clusterName)
	if err != nil {
		return err
	}

	var graphs []mgmtclientv3.ClusterMonitorGraph
	if err = access.List(apiContext, apiContext.Version, mgmtclientv3.ClusterMonitorGraphType, &types.QueryOptions{Conditions: inputParser.Conditions}, &graphs); err != nil {
		return err
	}

	var queries []*PrometheusQuery
	for _, graph := range graphs {
		g := graph
		graphName := getRefferenceGraphName(g.ClusterID, g.Name)
		monitorMetrics, err := graph2Metrics(userContext, mgmtClient, clusterName, g.ResourceType, graphName, g.MetricsSelector, g.DetailsMetricsSelector, inputParser.Input.MetricParams, inputParser.Input.IsDetails)
		if err != nil {
			return err
		}

		queries = append(queries, metrics2PrometheusQuery(monitorMetrics, inputParser.Start, inputParser.End, inputParser.Step, isInstanceGraph(g.GraphType))...)
	}

	seriesSlice, err := prometheusQuery.Do(queries)
	if err != nil {
		logrus.WithError(err).Warn("query series failed")
		return httperror.NewAPIError(httperror.ServerError, "Failed to obtain metrics. The metrics service may not be available.")
	}

	if seriesSlice == nil {
		apiContext.WriteResponse(http.StatusNoContent, nil)
		return nil
	}

	collection := v3.QueryClusterGraphOutput{Type: "collection"}
	for k, v := range seriesSlice {
		graphName, resourceType, _ := parseID(k)
		series := convertInstance(v, nodeMap, resourceType)
		queryGraph := v3.QueryClusterGraph{
			GraphName: graphName,
			Series:    series,
		}
		collection.Data = append(collection.Data, queryGraph)
	}

	res, err := json.Marshal(collection)
	if err != nil {
		return fmt.Errorf("marshal query series result failed, %v", err)
	}

	apiContext.Response.Write(res)
	return nil
}

type metricWrap struct {
	v3.MonitorMetric
	ExecuteExpression          string
	ReferenceGraphName         string
	ReferenceGraphResourceType string
}

func graph2Metrics(userContext *config.UserContext, mgmtClient v3.Interface, clusterName, resourceType, refGraphName string, metricSelector, detailsMetricSelector map[string]string, metricParams map[string]string, isDetails bool) ([]*metricWrap, error) {
	nodeLister := mgmtClient.Nodes(metav1.NamespaceAll).Controller().Lister()
	newMetricParams, err := parseMetricParams(userContext, nodeLister, resourceType, clusterName, metricParams)
	if err != nil {
		return nil, err
	}

	var excuteMetrics []*metricWrap
	var set labels.Set
	if isDetails && detailsMetricSelector != nil {
		set = labels.Set(detailsMetricSelector)
	} else {
		set = labels.Set(metricSelector)
	}
	metrics, err := mgmtClient.MonitorMetrics(clusterName).List(metav1.ListOptions{LabelSelector: set.AsSelector().String()})
	if err != nil {
		return nil, fmt.Errorf("list metrics failed, %v", err)
	}

	for _, v := range metrics.Items {
		executeExpression := replaceParams(newMetricParams, v.Spec.Expression)
		excuteMetrics = append(excuteMetrics, &metricWrap{
			MonitorMetric:              *v.DeepCopy(),
			ExecuteExpression:          executeExpression,
			ReferenceGraphName:         refGraphName,
			ReferenceGraphResourceType: resourceType,
		})
	}
	return excuteMetrics, nil
}

func metrics2PrometheusQuery(metrics []*metricWrap, start, end time.Time, step time.Duration, isInstanceQuery bool) []*PrometheusQuery {
	var queries []*PrometheusQuery
	for _, v := range metrics {
		id := getPrometheusQueryID(v.ReferenceGraphName, v.ReferenceGraphResourceType, v.Name)
		queries = append(queries, InitPromQuery(id, start, end, step, v.ExecuteExpression, v.Spec.LegendFormat, isInstanceQuery))
	}
	return queries
}

func nodeName2InternalIP(nodeLister v3.NodeLister, clusterName, nodeName string) (string, error) {
	_, name := ref.Parse(nodeName)
	node, err := nodeLister.Get(clusterName, name)
	if err != nil {
		return "", fmt.Errorf("get node from mgmt failed, %v", err)
	}

	internalNodeIP := getInternalNodeIP(node)
	if internalNodeIP == "" {
		return "", fmt.Errorf("could not find endpoint ip address for node %s", nodeName)
	}

	return internalNodeIP, nil
}

func getNodeName2InternalIPMap(nodeLister v3.NodeLister, clusterName string) (map[string]string, error) {
	nodeMap := make(map[string]string)
	nodes, err := nodeLister.List(clusterName, labels.NewSelector())
	if err != nil {
		return nil, fmt.Errorf("list node from mgnt failed, %v", err)
	}

	for _, node := range nodes {
		internalNodeIP := getInternalNodeIP(node)
		if internalNodeIP != "" {
			nodeMap[internalNodeIP] = node.Status.NodeName
		}
	}
	return nodeMap, nil
}

func getInternalNodeIP(node *v3.Node) string {
	for _, ip := range node.Status.InternalNodeStatus.Addresses {
		if ip.Type == "InternalIP" && ip.Address != "" {
			return ip.Address
		}
	}
	return ""
}

func getPrometheusQueryID(graphName, graphResoureceType, metricName string) string {
	return fmt.Sprintf("%s_%s_%s", graphName, graphResoureceType, metricName)
}

func parseID(ref string) (graphName, resourceType, metricName string) {
	parts := strings.SplitN(ref, "_", 3)

	if len(parts) < 2 {
		return parts[0], "", ""
	}

	if len(parts) == 2 {
		return parts[0], parts[1], ""
	}

	if len(parts) == 3 {
		return parts[0], parts[1], parts[2]
	}
	return parts[0], parts[1], parts[1]
}

func convertInstance(seriesSlice []*TimeSeries, nodeMap map[string]string, resourceType string) []*v3.TimeSeries {
	var series []*v3.TimeSeries
	for _, v := range seriesSlice {
		name := v.Name

		if resourceType == ResourceCluster || resourceType == ResourceNode || resourceType == ResourceAPIServer || resourceType == ResourceEtcd || resourceType == ResourceScheduler || resourceType == ResourceControllerManager || resourceType == ResourceFluentd || resourceType == ResourceIngressController {
			hostName := strings.Split(v.Tags["instance"], ":")[0]
			if v.Name != "" && nodeMap[hostName] != "" {
				name = strings.Replace(v.Name, v.Tags["instance"], nodeMap[hostName], -1)
			}
		}

		series = append(series, &v3.TimeSeries{
			Name:   name,
			Points: v.Points,
		})
	}
	return series
}

func getRefferenceGraphName(namespace, name string) string {
	return fmt.Sprintf("%s:%s", namespace, name)
}