package privatelinkendpoint

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/privatelinkendpoint/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("PrivateLinkEndpointReconciler")

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

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

//+kubebuilder:rbac:groups=dedicated.regionalserver.tidbcloud.com,resources=privatelinkendpoint,verbs=get;list;watch;create;update;patch;delete
//+kubebuilder:rbac:groups=dedicated.regionalserver.tidbcloud.com,resources=privatelinkendpoint/status,verbs=get;update;patch
//+kubebuilder:rbac:groups=dedicated.regionalserver.tidbcloud.com,resources=privatelinkendpoint/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 *PrivateLinkEndpointReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
	logger := r.Log.WithValues("privatelinkendpoint", req.NamespacedName)
	logger.Info("Reconciling RegionalServer PrivateLinkEndpoint")
	start := time.Now()
	defer func() {
		logger.Info("Finished reconciling RegionalServer PrivateLinkEndpoint", "took", time.Since(start))
	}()
	var privatelinkendpoint v1alpha1.PrivateLinkEndpoint
	if err := r.PrivateLinkEndpointRW.Get(ctx, req.NamespacedName, &privatelinkendpoint); err != nil {
		if apierrors.IsNotFound(err) {
			return ctrl.Result{}, nil
		}
		return ctrl.Result{}, fmt.Errorf("failed to get PrivateLinkEndpoint %s: %w", req.NamespacedName, err)
	}
	if utils.IsPaused(privatelinkendpoint.GetObjectMeta()) {
		logger.Info("reconciliation is paused either through the pause annotation",
			"annotation", v1alpha1.AnnotationKeyReconciliationPaused,
			"privatelinkendpoint", req.NamespacedName.String(),
		)
		r.EventRecorder.Event(&privatelinkendpoint, corev1.EventTypeWarning, "ReconciliationPaused", "reconciliation is paused through the annotation "+v1alpha1.AnnotationKeyReconciliationPaused)
		return ctrl.Result{}, nil
	}

	providerType := privatelinkendpoint.Spec.Provider
	if providerType != r.Config.Provider {
		logger.Info("Skip reconciling PrivateLinkEndpoint 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: privatelinkendpoint.Spec.VPCRef.Name, Namespace: privatelinkendpoint.Spec.VPCRef.Namespace}, &vpc); err != nil {
		return ctrl.Result{}, fmt.Errorf("failed to get VPC %s: %w", privatelinkendpoint.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(&privatelinkendpoint, dataPlaneName)
	}

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

	tasks := GetPrivateLinkEndpointTasks(r, c)
	if privatelinkendpoint.DeletionTimestamp.IsZero() {
		tasks = r.setHookOnTasks(tasks, c)

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

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

	return res, err
}

func (r *PrivateLinkEndpointReconciler) 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 PrivateLinkEndpoint as available")
		c.PrivateLinkEndpoint.Status.Phase = v1alpha1.PrivateLinkEndpointPhaseAvailable
		c.PrivateLinkEndpoint.Status.Message = ""
	}

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

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

	return res, err
}

func updatePrivateLinkEndpoint(ctx context.Context, rw repository.PrivateLinkEndpointReaderWriter, ple *v1alpha1.PrivateLinkEndpoint) error {
	pleStatus := ple.Status.DeepCopy()
	if err := rw.Update(ctx, ple); err != nil {
		return err
	}
	ple.Status = *pleStatus
	return rw.UpdateStatus(ctx, ple)
}

func (r *PrivateLinkEndpointReconciler) 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.PrivateLinkEndpoint, v1alpha1.Finalizer)
	}

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

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

	return res, err
}

func (r *PrivateLinkEndpointReconciler) 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.PrivateLinkEndpoint.Annotations[passTimeKey]
		if !ok {
			return
		}
		if c.PrivateLinkEndpoint.Annotations == nil {
			c.PrivateLinkEndpoint.Annotations = map[string]string{}
		}
		age := time.Since(c.PrivateLinkEndpoint.CreationTimestamp.Time)
		c.PrivateLinkEndpoint.Annotations[passTimeKey] = age.String()
		log.FromContext(ctx).Info("pass task when creating privatelinkendpoint", "task", name, "age", age.String())
	}
	for idx, task := range tasks {
		tasks[idx] = deploy.NewTaskWraper(task, hook, tracer)
	}
	return tasks
}

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