package privatelinkservice

import (
	"context"
	"fmt"
	"time"

	"github.com/go-logr/logr"
	"go.opentelemetry.io/otel"
	"go.opentelemetry.io/otel/attribute"
	"go.opentelemetry.io/otel/trace"
	corev1 "k8s.io/api/core/v1"
	apierrors "k8s.io/apimachinery/pkg/api/errors"
	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/apimachinery/pkg/types"
	"k8s.io/client-go/tools/record"
	ctrl "sigs.k8s.io/controller-runtime"
	"sigs.k8s.io/controller-runtime/pkg/builder"
	"sigs.k8s.io/controller-runtime/pkg/client"
	"sigs.k8s.io/controller-runtime/pkg/controller"
	"sigs.k8s.io/controller-runtime/pkg/controller/controllerutil"
	"sigs.k8s.io/controller-runtime/pkg/log"
	"sigs.k8s.io/controller-runtime/pkg/predicate"

	"github.com/tidbcloud/infra-provider/regional-server/api/v1alpha1"
	"github.com/tidbcloud/infra-provider/regional-server/pkg/cloud/aliyun"
	"github.com/tidbcloud/infra-provider/regional-server/pkg/cloud/aws"
	"github.com/tidbcloud/infra-provider/regional-server/pkg/cloud/azure"
	"github.com/tidbcloud/infra-provider/regional-server/pkg/common/utils"
	"github.com/tidbcloud/infra-provider/regional-server/pkg/config"
	"github.com/tidbcloud/infra-provider/regional-server/pkg/controllers"
	"github.com/tidbcloud/infra-provider/regional-server/pkg/controllers/privatelinkservice/task"
	"github.com/tidbcloud/infra-provider/regional-server/pkg/deploy"
	"github.com/tidbcloud/infra-provider/regional-server/pkg/k8s"
	"github.com/tidbcloud/infra-provider/regional-server/pkg/o11y/tracing"
	"github.com/tidbcloud/infra-provider/regional-server/pkg/repository"
	tracerutil "github.com/tidbcloud/infra-provider/regional-server/pkg/tracer"
)

var tracer = otel.Tracer("InternetReconciler")

type PrivateLinkServiceReconciler struct {
	client.Client
	Log                  logr.Logger
	Scheme               *runtime.Scheme
	EventRecorder        record.EventRecorder
	VPCR                 repository.VPCReader
	PrivateLinkServiceRW repository.PrivateLinkServiceReaderWriter
	Config               config.RootConfig
	awsCli               aws.Client
	aliyunCli            aliyun.Client
	azureCli             azure.Client
}

func NewPrivateLinkServiceReconciler(
	client client.Client,
	log logr.Logger,
	scheme *runtime.Scheme,
	eventRecorder record.EventRecorder,
	conf config.RootConfig,
	awsCli aws.Client,
	aliyunCli aliyun.Client,
	azureCli azure.Client,
) *PrivateLinkServiceReconciler {
	return &PrivateLinkServiceReconciler{
		Client:               client,
		Log:                  log,
		Scheme:               scheme,
		EventRecorder:        eventRecorder,
		VPCR:                 repository.NewVPCReader(client),
		PrivateLinkServiceRW: repository.NewPrivateLinkServiceReaderWriter(client),
		Config:               conf,
		awsCli:               awsCli,
		aliyunCli:            aliyunCli,
		azureCli:             azureCli,
	}
}

//+kubebuilder:rbac:groups=dedicated.regionalserver.tidbcloud.com,resources=privatelinkservice,verbs=get;list;watch;create;update;patch;delete
//+kubebuilder:rbac:groups=dedicated.regionalserver.tidbcloud.com,resources=privatelinkservice/status,verbs=get;update;patch
//+kubebuilder:rbac:groups=dedicated.regionalserver.tidbcloud.com,resources=privatelinkservice/finalizers,verbs=update
//+kubebuilder:rbac:groups=dedicated.regionalserver.tidbcloud.com,resources=vpc,verbs=get;list;watch;create;update;patch;delete
//+kubebuilder:rbac:groups=dedicated.regionalserver.tidbcloud.com,resources=vpc/status,verbs=get;update;patch
//+kubebuilder:rbac:groups=dedicated.regionalserver.tidbcloud.com,resources=vpc/finalizers,verbs=update

// Reconcile is part of the main kubernetes reconciliation loop which aims to
// move the current state of the internet closer to the desired state.
func (r *PrivateLinkServiceReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
	logger := r.Log.WithValues("privatelinkservice", req.NamespacedName)
	logger.Info("Reconciling RegionalServer PrivateLinkService")
	start := time.Now()
	defer func() {
		logger.Info("Finished reconciling RegionalServer PrivateLinkService", "took", time.Since(start))
	}()
	var privatelinkservice v1alpha1.PrivateLinkService
	if err := r.PrivateLinkServiceRW.Get(ctx, req.NamespacedName, &privatelinkservice); err != nil {
		if apierrors.IsNotFound(err) {
			return ctrl.Result{}, nil
		}
		return ctrl.Result{}, fmt.Errorf("failed to get PrivateLinkService %s: %w", req.NamespacedName, err)
	}
	if utils.IsPaused(privatelinkservice.GetObjectMeta()) {
		logger.Info("reconciliation is paused either through the pause annotation",
			"annotation", v1alpha1.AnnotationKeyReconciliationPaused,
			"privatelinkservice", req.NamespacedName.String(),
		)
		r.EventRecorder.Event(&privatelinkservice, corev1.EventTypeWarning, "ReconciliationPaused", "reconciliation is paused through the annotation "+v1alpha1.AnnotationKeyReconciliationPaused)
		return ctrl.Result{}, nil
	}

	providerType := privatelinkservice.Spec.Provider
	if providerType != r.Config.Provider {
		logger.Info("Skip reconciling PrivateLinkService because provider type is not matched", "providerType", providerType, "configProviderType", r.Config.Provider)
		return ctrl.Result{}, nil
	}

	vpc := v1alpha1.VPC{}
	if err := r.VPCR.Get(ctx, types.NamespacedName{Name: privatelinkservice.Spec.VPCRef.Name, Namespace: privatelinkservice.Spec.VPCRef.Namespace}, &vpc); err != nil {
		// If VPC is already deleted but pls is not deleted yet, we can still proceed to delete pls. Otherwise return error
		// Because we need VPC info to create PrivateLinkService but not during delete process
		if apierrors.IsNotFound(err) && !privatelinkservice.DeletionTimestamp.IsZero() {
			logger.Info("VPC not found, but PrivateLinkService is deleting, proceed to delete PrivateLinkService", "vpc", privatelinkservice.Spec.VPCRef)
		} else {
			return ctrl.Result{}, fmt.Errorf("failed to get VPC %s: %w", privatelinkservice.Spec.VPCRef.Name, err)
		}
	}
	dataPlane := &v1alpha1.DataPlane{}
	if dataPlaneName := vpc.Labels[v1alpha1.DataPlaneIDKey]; dataPlaneName != "" {
		if err := r.Get(ctx, types.NamespacedName{Name: dataPlaneName, Namespace: r.Config.Namespace}, dataPlane); err != nil {
			return ctrl.Result{}, fmt.Errorf("failed to get DataPlane %s: %w", dataPlaneName, err)
		}
		controllers.EnsureDataPlaneIDLabel(&privatelinkservice, dataPlaneName)
	}

	c, err := (&task.Context{
		Local:                r.Client,
		Logger:               logger,
		PrivateLinkService:   &privatelinkservice,
		DataPlane:            dataPlane,
		VPC:                  &vpc,
		VPCR:                 r.VPCR,
		PrivateLinkServiceRW: r.PrivateLinkServiceRW,
		Config:               r.Config,
	}).Default()
	if err != nil {
		return ctrl.Result{}, fmt.Errorf("failed to create task context: %w", err)
	}

	tasks := GetPrivateLinkServiceTasks(r, c)
	if privatelinkservice.DeletionTimestamp.IsZero() && isNotReadyPrivateLinkService(privatelinkservice) {
		tasks = r.setHookOnTasks(tasks, c)

		// TODO: refactor tracing
		var span trace.Span
		ctx, span = tracer.Start(tracing.ExtractTraceContext(ctx, &privatelinkservice), "Internet Reconcile")
		span.SetAttributes(
			attribute.String("internet", privatelinkservice.Name),
			attribute.String("namespace", privatelinkservice.Namespace),
			attribute.String("provider", privatelinkservice.Spec.Provider),
			attribute.String("region", privatelinkservice.Spec.Region),
		)
		defer func() { tracerutil.EndSpan(span, err) }()
	}

	d := deploy.NewDeployer(tasks, nil, logger)
	var res ctrl.Result
	if privatelinkservice.DeletionTimestamp.IsZero() {
		res, err = r.updateCreate(ctx, logger, c, d.Deploy(ctx))
	} else {
		if controllers.DeletionConfirmed(&privatelinkservice) {
			privatelinkservice.Status.Phase = v1alpha1.PrivateLinkServicePhaseDeleting
			if err := r.PrivateLinkServiceRW.UpdateStatus(ctx, &privatelinkservice); err != nil {
				return ctrl.Result{}, fmt.Errorf("failed to update PrivateLinkService status: %w", err)
			}
			res, err = r.updateDelete(ctx, logger, c, d.Destroy(ctx))
		} else {
			logger.Info("waiting for privatelinkservice deletion to be confirmed")
			return ctrl.Result{}, fmt.Errorf("privatelinkservice deletion is not confirmed")
		}
	}
	if err == nil {
		r.EventRecorder.Event(&privatelinkservice, "Normal", "Reconcile", "Reconcile successfully")
	} else {
		r.EventRecorder.Event(&privatelinkservice, "Warning", "Reconcile", fmt.Sprintf("Reconcile failed: %v", err))
	}

	return res, err
}

func (r *PrivateLinkServiceReconciler) updateCreate(ctx context.Context, log logr.Logger, c *task.Context, results []deploy.Result) (ctrl.Result, error) {
	res, err, retriableErrs := deploy.MinRequeue(results)
	if err == nil && retriableErrs == nil {
		log.Info("Mark PrivateLinkService as active")
		c.PrivateLinkService.Status.Phase = v1alpha1.PrivateLinkServicePhaseActive
		c.PrivateLinkService.Status.Message = ""
	}

	if err != nil {
		log.Error(err, "Failed to reconcile PrivateLinkService")
		c.PrivateLinkService.Status.Message = err.Error()
	}

	if e := updatePrivateLinkService(ctx, r.PrivateLinkServiceRW, c.PrivateLinkService); e != nil {
		log.Error(e, "Failed to update PrivateLinkService")
		return res, fmt.Errorf("failed to update PrivateLinkService: %w", e)
	}

	return res, err
}

func updatePrivateLinkService(ctx context.Context, rw repository.PrivateLinkServiceReaderWriter, pls *v1alpha1.PrivateLinkService) error {
	plsStatus := pls.Status.DeepCopy()
	if plsStatus.VPCID != "" {
		pls.Labels[v1alpha1.VPCIDKey] = plsStatus.VPCID
	}

	if err := rw.Update(ctx, pls); err != nil {
		return err
	}
	if err := rw.Get(ctx, client.ObjectKeyFromObject(pls), pls); err != nil {
		return err
	}
	pls.Status = *plsStatus
	return rw.UpdateStatus(ctx, pls)
}

func (r *PrivateLinkServiceReconciler) updateDelete(ctx context.Context, log logr.Logger, c *task.Context, results []deploy.Result) (ctrl.Result, error) {
	res, err, retriableErrs := deploy.MinRequeue(results)
	if err == nil && retriableErrs == nil {
		controllerutil.RemoveFinalizer(c.PrivateLinkService, v1alpha1.Finalizer)
	}

	if e := r.PrivateLinkServiceRW.Update(ctx, c.PrivateLinkService); e != nil {
		log.Error(e, "Failed to update PrivateLinkService")
		return res, fmt.Errorf("failed to update PrivateLinkService: %w", e)
	}

	if retriableErrs != nil {
		log.Error(err, "Requeue for updateDelete", "after", res.RequeueAfter.String())
	}

	return res, err
}

func (r *PrivateLinkServiceReconciler) setHookOnTasks(tasks []deploy.Task, c *task.Context) []deploy.Task {
	hook := func(ctx context.Context, task deploy.Task) {
		name := task.Name()
		passTimeKey := utils.GenTaskFirstPastAnnotationKey(name)
		_, ok := c.PrivateLinkService.Annotations[passTimeKey]
		if !ok {
			return
		}
		if c.PrivateLinkService.Annotations == nil {
			c.PrivateLinkService.Annotations = map[string]string{}
		}
		age := time.Since(c.PrivateLinkService.CreationTimestamp.Time)
		c.PrivateLinkService.Annotations[passTimeKey] = age.String()
		log.FromContext(ctx).Info("pass task when creating privatelinkservice", "task", name, "age", age.String())
	}
	for idx, task := range tasks {
		tasks[idx] = deploy.NewTaskWraper(task, hook, tracer)
	}
	return tasks
}

func isNotReadyPrivateLinkService(privatelinkservice v1alpha1.PrivateLinkService) bool {
	return privatelinkservice.Status.Phase != v1alpha1.PrivateLinkServicePhaseActive &&
		privatelinkservice.Status.Phase != v1alpha1.PrivateLinkServicePhaseReadyForCreate &&
		privatelinkservice.Status.Phase != v1alpha1.PrivateLinkServicePhaseDeleting
}

func (r *PrivateLinkServiceReconciler) SetupWithManager(mgr ctrl.Manager, pds ...predicate.Predicate) error {
	if err := mgr.GetFieldIndexer().IndexField(context.Background(), &v1alpha1.PrivateLinkService{}, controllers.VPCNameField, func(o client.Object) []string {
		i := o.(*v1alpha1.PrivateLinkService)
		return []string{i.Spec.VPCRef.Name}
	}); err != nil {
		return err
	}
	return ctrl.NewControllerManagedBy(mgr).
		For(&v1alpha1.PrivateLinkService{}, builder.WithPredicates(pds...)).
		WithOptions(controller.Options{RateLimiter: k8s.RetryLimiter, MaxConcurrentReconciles: 5}).
		WithEventFilter(predicate.Or(
			predicate.GenerationChangedPredicate{},
			predicate.LabelChangedPredicate{},
			predicate.AnnotationChangedPredicate{},
		)).
		Complete(r)
}