package kubernetes

import (
	"encoding/json"
	"fmt"
	"strconv"
	"sync"

	"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
	"github.com/VictoriaMetrics/VictoriaMetrics/lib/promscrape/discoveryutils"
)

// parseEndpointsList parses EndpointSliceList from data.
func parseEndpointSlicesList(data []byte) (*EndpointSliceList, error) {
	var esl EndpointSliceList
	if err := json.Unmarshal(data, &esl); err != nil {
		return nil, fmt.Errorf("cannot unmarshal EndpointSliceList from %q: %w", data, err)
	}

	return &esl, nil
}

// appendTargetLabels injects labels for endPointSlice to slice map
// follows TargetRef for enrich labels with pod and service metadata
func (eps *EndpointSlice) appendTargetLabels(ms []map[string]string, podsCache, servicesCache *sync.Map) []map[string]string {
	var svc *Service
	if s, ok := servicesCache.Load(eps.key()); ok {
		svc = s.(*Service)
	}
	podPortsSeen := make(map[*Pod][]int)
	for _, ess := range eps.Endpoints {
		var pod *Pod
		if p, ok := podsCache.Load(ess.TargetRef.key()); ok {
			pod = p.(*Pod)
		}
		for _, epp := range eps.Ports {
			for _, addr := range ess.Addresses {
				ms = append(ms, getEndpointSliceLabelsForAddressAndPort(podPortsSeen, addr, eps, ess, epp, pod, svc))
			}

		}
	}

	// Append labels for skipped ports on seen pods.
	portSeen := func(port int, ports []int) bool {
		for _, p := range ports {
			if p == port {
				return true
			}
		}
		return false
	}
	for p, ports := range podPortsSeen {
		for _, c := range p.Spec.Containers {
			for _, cp := range c.Ports {
				if portSeen(cp.ContainerPort, ports) {
					continue
				}
				addr := discoveryutils.JoinHostPort(p.Status.PodIP, cp.ContainerPort)
				m := map[string]string{
					"__address__": addr,
				}
				p.appendCommonLabels(m)
				p.appendContainerLabels(m, c, &cp)
				if svc != nil {
					svc.appendCommonLabels(m)
				}
				ms = append(ms, m)
			}
		}
	}
	return ms

}

// getEndpointSliceLabelsForAddressAndPort gets labels for endpointSlice
// from  address, Endpoint and EndpointPort
// enriches labels with TargetRef
// pod appended to seen Ports
// if TargetRef matches
func getEndpointSliceLabelsForAddressAndPort(podPortsSeen map[*Pod][]int, addr string, eps *EndpointSlice, ea Endpoint, epp EndpointPort, p *Pod, svc *Service) map[string]string {
	m := getEndpointSliceLabels(eps, addr, ea, epp)
	if svc != nil {
		svc.appendCommonLabels(m)
	}
	if ea.TargetRef.Kind != "Pod" || p == nil {
		return m
	}
	p.appendCommonLabels(m)
	for _, c := range p.Spec.Containers {
		for _, cp := range c.Ports {
			if cp.ContainerPort == epp.Port {
				p.appendContainerLabels(m, c, &cp)
				podPortsSeen[p] = append(podPortsSeen[p], cp.ContainerPort)
				break
			}
		}
	}

	return m
}

// //getEndpointSliceLabels builds labels for given EndpointSlice
func getEndpointSliceLabels(eps *EndpointSlice, addr string, ea Endpoint, epp EndpointPort) map[string]string {

	addr = discoveryutils.JoinHostPort(addr, epp.Port)
	m := map[string]string{
		"__address__":                                               addr,
		"__meta_kubernetes_namespace":                               eps.Metadata.Namespace,
		"__meta_kubernetes_endpointslice_name":                      eps.Metadata.Name,
		"__meta_kubernetes_endpointslice_address_type":              eps.AddressType,
		"__meta_kubernetes_endpointslice_endpoint_conditions_ready": strconv.FormatBool(ea.Conditions.Ready),
		"__meta_kubernetes_endpointslice_port_name":                 epp.Name,
		"__meta_kubernetes_endpointslice_port_protocol":             epp.Protocol,
		"__meta_kubernetes_endpointslice_port":                      strconv.Itoa(epp.Port),
	}
	if epp.AppProtocol != "" {
		m["__meta_kubernetes_endpointslice_port_app_protocol"] = epp.AppProtocol
	}
	if ea.TargetRef.Kind != "" {
		m["__meta_kubernetes_endpointslice_address_target_kind"] = ea.TargetRef.Kind
		m["__meta_kubernetes_endpointslice_address_target_name"] = ea.TargetRef.Name
	}
	if ea.Hostname != "" {
		m["__meta_kubernetes_endpointslice_endpoint_hostname"] = ea.Hostname
	}
	for k, v := range ea.Topology {
		m["__meta_kubernetes_endpointslice_endpoint_topology_"+discoveryutils.SanitizeLabelName(k)] = v
		m["__meta_kubernetes_endpointslice_endpoint_topology_present_"+discoveryutils.SanitizeLabelName(k)] = "true"
	}
	return m
}

// EndpointSliceList - implements kubernetes endpoint slice list object,
// that groups service endpoints slices.
// https://v1-17.docs.kubernetes.io/docs/reference/generated/kubernetes-api/v1.17/#endpointslice-v1beta1-discovery-k8s-io
type EndpointSliceList struct {
	Items    []EndpointSlice
	Metadata listMetadata `json:"metadata"`
}

// EndpointSlice - implements kubernetes endpoint slice.
// https://v1-17.docs.kubernetes.io/docs/reference/generated/kubernetes-api/v1.17/#endpointslice-v1beta1-discovery-k8s-io
type EndpointSlice struct {
	Metadata    ObjectMeta
	Endpoints   []Endpoint
	AddressType string
	Ports       []EndpointPort
}

func (eps EndpointSlice) key() string {
	return eps.Metadata.Namespace + "/" + eps.Metadata.Name
}

// Endpoint implements kubernetes object endpoint for endpoint slice.
// https://v1-17.docs.kubernetes.io/docs/reference/generated/kubernetes-api/v1.17/#endpoint-v1beta1-discovery-k8s-io
type Endpoint struct {
	Addresses  []string
	Conditions EndpointConditions
	Hostname   string
	TargetRef  ObjectReference
	Topology   map[string]string
}

// EndpointConditions implements kubernetes endpoint condition.
// https://v1-17.docs.kubernetes.io/docs/reference/generated/kubernetes-api/v1.17/#endpointconditions-v1beta1-discovery-k8s-io
type EndpointConditions struct {
	Ready bool
}

func processEndpointSlices(cfg *apiConfig, sc *SharedKubernetesCache, p *EndpointSlice, action string) {
	key := buildSyncKey("endpointslices", cfg.setName, p.key())
	switch action {
	case "ADDED", "MODIFIED":
		cfg.targetChan <- SyncEvent{
			Labels:           p.appendTargetLabels(nil, sc.Pods, sc.Services),
			Key:              key,
			ConfigSectionSet: cfg.setName,
		}
	case "DELETED":
		cfg.targetChan <- SyncEvent{
			Key:              key,
			ConfigSectionSet: cfg.setName,
		}
	case "ERROR":
	default:
		logger.Warnf("unexpected action: %s", action)
	}
}