package internal

import (
	"fmt"
	"strings"
	"time"

	log "github.com/sirupsen/logrus"
	v1 "k8s.io/api/coordination/v1"
	"k8s.io/client-go/informers"
	"k8s.io/client-go/tools/cache"
)

func StartLeaseInformer(cfg *Config, stopCh <-chan struct{}) error {
	log.WithFields(log.Fields{"Caller": "StartLeaseInformer"}).Info("Starting lease informer")

	client, err := generateClient()
	if err != nil {
		return fmt.Errorf("Could not generate client for informer: %s", err.Error())
	}
	factory := informers.NewSharedInformerFactoryWithOptions(client, 0, informers.WithNamespace("kube-system"))
	leaseInformer := factory.Coordination().V1().Leases().Informer()

	leaseInformer.AddEventHandler(cache.ResourceEventHandlerFuncs{
		AddFunc: func(obj interface{}) {
			if l, ok := obj.(*v1.Lease); ok {
				log.WithFields(log.Fields{"Caller": "lease.Add", "Lease": l.Name, "RV": l.ResourceVersion}).Debug("Add event for lease")
			}
			handleLease(obj, cfg)
		},
		UpdateFunc: func(oldObj, newObj interface{}) {
			oldL, okOld := oldObj.(*v1.Lease)
			newL, okNew := newObj.(*v1.Lease)
			if okOld {
				log.WithFields(log.Fields{"Caller": "lease.Update.old", "Lease": oldL.Name, "RV": oldL.ResourceVersion}).Debug("Old lease")
			}
			if okNew {
				log.WithFields(log.Fields{"Caller": "lease.Update.new", "Lease": newL.Name, "RV": newL.ResourceVersion}).Debug("New lease")
			}
			// Only handle when either:
			// - the object is not parseable as Lease (defensive), or
			// - it's an Add-like event (old not present), or
			// - HolderIdentity actually changed compared to previous object.
			if okOld && okNew {
				// If resourceVersion didn't change, skip (no real update)
				if oldL.ResourceVersion == newL.ResourceVersion {
					return
				}
				oldHolder := ""
				newHolder := ""
				if oldL.Spec.HolderIdentity != nil {
					oldHolder = *oldL.Spec.HolderIdentity
				}
				if newL.Spec.HolderIdentity != nil {
					newHolder = *newL.Spec.HolderIdentity
				}
				if oldHolder == newHolder {
					return
				}
			}
			handleLease(newObj, cfg)
		},
		DeleteFunc: func(obj interface{}) {
			handleLeaseDelete(obj, cfg)
		},
	})

	factory.Start(stopCh)

	// wait for cache sync with timeout
	synced := make(chan struct{})
	go func() {
		if !cache.WaitForCacheSync(stopCh, leaseInformer.HasSynced) {
			close(synced)
			return
		}
		close(synced)
	}()

	select {
	case <-synced:
		// proceed
	case <-time.After(15 * time.Second):
		return fmt.Errorf("timed out waiting for informer cache sync")
	}

	log.WithFields(log.Fields{"Caller": "StartLeaseInformer"}).Info("Lease informer running")
	return nil
}

func handleLease(obj interface{}, cfg *Config) {
	lease, ok := obj.(*v1.Lease)
	if !ok {
		log.WithFields(log.Fields{"Caller": "handleLease"}).Warn("Could not cast object to Lease")
		return
	}

	if lease == nil {
		return
	}

	if lease.Name == "" || len(lease.Name) < 1 {
		return
	}

	if !strings.HasPrefix(lease.Name, "cilium-l2announce") {
		return
	}

	node, err := GetNodeNameFromLease(*lease)
	if err != nil {
		log.WithFields(log.Fields{"Caller": "handleLease", "Lease": lease.Name}).Errorf("Error parsing lease: %s", err.Error())
		return
	}

	if cfg.DryRun {
		log.WithFields(log.Fields{"Caller": "handleLease"}).Infof("Dry run: would label node %s with %s=true (lease %s)", node, cfg.CiliumLabel, lease.Name)
		return
	}

	err = LabelNode(node, lease.Name, cfg)
	if err != nil {
		log.WithFields(log.Fields{"Caller": "handleLease", "Node": node, "Lease": lease.Name}).Errorf("Error labeling node: %s", err.Error())
	}
}

func handleLeaseDelete(obj interface{}, cfg *Config) {
	lease, ok := obj.(*v1.Lease)
	if !ok {
		log.WithFields(log.Fields{"Caller": "handleLeaseDelete"}).Warn("Could not cast object to Lease")
		return
	}

	if lease == nil {
		return
	}

	if lease.Name == "" || len(lease.Name) < 1 {
		return
	}

	if !strings.HasPrefix(lease.Name, "cilium-l2announce") {
		return
	}

	node, err := GetNodeNameFromLease(*lease)
	if err != nil {
		log.WithFields(log.Fields{"Caller": "handleLeaseDelete", "Lease": lease.Name}).Errorf("Error parsing lease: %s", err.Error())
		return
	}

	if cfg.DryRun {
		log.WithFields(log.Fields{"Caller": "handleLeaseDelete"}).Infof("Dry run: would remove labels %s and %s from node %s (lease %s)", node, cfg.CiliumLabel, "cilium.uploadfilter24.eu/lease", lease.Name)
		return
	}

	err = RemoveLabelFromNode(node, lease.Name, cfg)
	if err != nil {
		log.WithFields(log.Fields{"Caller": "handleLeaseDelete", "Node": node, "Lease": lease.Name}).Errorf("Error labeling node: %s", err.Error())
	}
}