package vpc

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/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/vpc/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/namer"
	"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("VPCReconciler")

type VPCReconciler struct {
	client.Client
	Log           logr.Logger
	Scheme        *runtime.Scheme
	EventRecorder record.EventRecorder
	// TODO: use it to instead of vpc read and write by client.Client
	VPCRW repository.VPCReaderWriter
	// Dependent objects reader, used to check if the dependent objects are deleted before deleting VPC
	APPBoxR              repository.APPBoxReader
	InternetR            repository.InternetReader
	PrivateLinkServiceR  repository.PrivateLinkServiceReader
	PrivateLinkEndpointR repository.PrivateLinkEndpointReader
	VPCPeeringR          repository.VPCPeeringReader
	Config               config.RootConfig
}

func NewVPCReconciler(client client.Client, log logr.Logger, scheme *runtime.Scheme, recorder record.EventRecorder, conf config.RootConfig) *VPCReconciler {
	return &VPCReconciler{
		Client:               client,
		Log:                  log,
		Scheme:               scheme,
		EventRecorder:        recorder,
		VPCRW:                repository.NewVPCReaderWriter(client),
		APPBoxR:              repository.NewAPPBoxReader(client),
		InternetR:            repository.NewInternetReader(client),
		PrivateLinkServiceR:  repository.NewPrivateLinkServiceReader(client),
		PrivateLinkEndpointR: repository.NewPrivateLinkEndpointReader(client),
		VPCPeeringR:          repository.NewVPCPeeringReader(client),
		Config:               conf,
	}
}

//+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 vpc closer to the desired state.
func (r *VPCReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
	logger := r.Log.WithValues("VPC", req.NamespacedName)
	logger.Info("Reconciling RegionalServer VPC")
	r.EventRecorder.Event(&v1alpha1.VPC{}, corev1.EventTypeNormal, "ReconcileStart", "")

	start := time.Now()
	defer func() {
		// metricsctrl.ReconcileDuration.
		// 	WithLabelValues("chaos_server").Observe(time.Since(start).Seconds())
		logger.Info("Finish RegionalServer VPC reconcile", "take", time.Since(start))
	}()

	var vpc v1alpha1.VPC
	if err := r.VPCRW.Get(ctx, req.NamespacedName, &vpc); err != nil {
		if apierrors.IsNotFound(err) {
			logger.Info("RegionalServer VPC not found")
			return ctrl.Result{}, nil
		}
		return ctrl.Result{}, fmt.Errorf("unable to get regionalserver vpc %s: %v", req.NamespacedName, err)
	}

	if utils.IsPaused(vpc.GetObjectMeta()) {
		logger.Info("reconciliation is paused either through the pause annotation",
			"annotation", v1alpha1.AnnotationKeyReconciliationPaused,
			"vpc", req.NamespacedName.String(),
		)
		r.EventRecorder.Event(&vpc, corev1.EventTypeWarning, "ReconciliationPaused", "reconciliation is paused through the annotation "+v1alpha1.AnnotationKeyReconciliationPaused)
		return ctrl.Result{}, nil
	}
	providerType := vpc.Spec.Provider
	if providerType != r.Config.Provider {
		logger.Info("Mismatched provider", "expect", r.Config.Provider, "got", providerType)
		return ctrl.Result{}, nil
	}

	c, err := (&task.Context{
		Local:                k8s.NewMutClientWithOwner(r.Client, vpc.DeepCopy(), namer.NewNamer()).Client(),
		Logger:               logger,
		VPC:                  &vpc,
		VPCRW:                r.VPCRW,
		APPBoxR:              r.APPBoxR,
		InternetR:            r.InternetR,
		PrivateLinkServiceR:  r.PrivateLinkServiceR,
		PrivateLinkEndpointR: r.PrivateLinkEndpointR,
		VPCPeeringR:          r.VPCPeeringR,
		Config:               r.Config,
	}).Default()
	if err != nil {
		return ctrl.Result{}, fmt.Errorf("failed to create a new context: %v", err)
	}
	tasks := GetVPCTasks(r, c)
	if vpc.DeletionTimestamp.IsZero() && isNotReadyVPC(&vpc) {
		tasks = r.setHookOnTasks(tasks, c)

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

	d := deploy.NewDeployer(tasks, nil, logger)

	var res ctrl.Result

	if vpc.DeletionTimestamp.IsZero() {
		res, err = r.updateCreate(ctx, logger, c, d.Deploy(ctx))
	} else {
		if controllers.DeletionConfirmed(&vpc) {
			vpc.Status.Phase = v1alpha1.VPCPhaseDeleting
			if err := r.VPCRW.UpdateStatus(ctx, &vpc); err != nil {
				return ctrl.Result{}, fmt.Errorf("failed to update vpc status: %v", err)
			}
			res, err = r.updateDelete(ctx, logger, c, d.Destroy(ctx))
		} else {
			logger.Info("waiting for vpc deletion to be confirmed")
			return ctrl.Result{}, fmt.Errorf("vpc deletion is not confirmed")
		}
	}

	if err == nil {
		r.EventRecorder.Event(&vpc, corev1.EventTypeNormal, "ReconcileSuccess", "")
	} else {
		r.EventRecorder.Event(&vpc, corev1.EventTypeWarning, "ReconcileFail", err.Error())
	}

	return res, err
}

func isNotReadyVPC(vpc *v1alpha1.VPC) bool {
	return vpc.Status.Phase != v1alpha1.VPCPhaseActive &&
		vpc.Status.Phase != v1alpha1.VPCPhaseReadyForDelete &&
		vpc.Status.Phase != v1alpha1.VPCPhaseDeleting
}

func (r *VPCReconciler) 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.VPC.Annotations[passTimeKey]
		if ok {
			return
		}
		if c.VPC.Annotations == nil {
			c.VPC.SetAnnotations(map[string]string{})
		}

		age := time.Since(c.VPC.GetCreationTimestamp().Time)
		c.VPC.Annotations[passTimeKey] = age.String()
		log.FromContext(ctx).Info("pass task when creating vpc", "task", name, "age", age.String())
	}
	for idx, task := range tasks {
		tasks[idx] = deploy.NewTaskWraper(task, hook, tracer)
	}
	return tasks
}

func (r *VPCReconciler) updateCreate(ctx context.Context, log logr.Logger, t *task.Context, results []deploy.Result) (ctrl.Result, error) {
	if vpcID := t.VPC.Status.VPC.VPCID; vpcID != "" {
		log = log.WithValues("vpcID", vpcID)
	}
	res, err, retriableErrs := deploy.MinRequeue(results)
	if err == nil && retriableErrs == nil {
		log.Info("Mark VPC as active")
		if t.VPC.Status.Phase != v1alpha1.VPCPhaseReadyForDelete {
			t.VPC.Status.Phase = v1alpha1.VPCPhaseActive
			t.VPC.Status.Reason = ""
		}
	}

	if err != nil {
		log.Error(err, "UpdateCreate VPC")
		t.VPC.Status.Reason = err.Error()
	}

	if e := updateVPC(ctx, t.VPCRW, t.VPC); e != nil {
		log.Error(e, "failed to update vpc")
		return res, fmt.Errorf("failed to update vpc: %v", e)
	}

	log.Info("requeue for updateCreate", "after", res.RequeueAfter.String())

	return res, err
}

func updateVPC(ctx context.Context, rw repository.VPCReaderWriter, vpc *v1alpha1.VPC) error {
	vpcStatus := vpc.Status.DeepCopy()
	if vpc.Status.VPC.VPCID != "" {
		vpc.Labels[v1alpha1.VPCIDKey] = vpc.Status.VPC.VPCID
	}

	if err := rw.Update(ctx, vpc); err != nil {
		return err
	}
	if err := rw.Get(ctx, types.NamespacedName{
		Namespace: vpc.Namespace,
		Name:      vpc.Name,
	}, vpc); err != nil {
		return err
	}
	vpc.Status = *vpcStatus
	return rw.UpdateStatus(ctx, vpc)
}

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

	if e := t.VPCRW.Update(ctx, t.VPC); e != nil {
		log.Error(e, "failed to update vpc")
		return res, fmt.Errorf("failed to update vpc: %v", e)
	}

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

	return res, err
}

func (r *VPCReconciler) SetupWithManager(mgr ctrl.Manager, pds ...predicate.Predicate) error {
	// GenerationChangedPredicate, LabelChanedPredicate and AnnotationChanedPredicate
	// are used to ignore status changes
	return ctrl.NewControllerManagedBy(mgr).
		For(&v1alpha1.VPC{}, builder.WithPredicates(pds...)).
		WithOptions(controller.Options{RateLimiter: k8s.RetryLimiter, MaxConcurrentReconciles: 5}).
		WithEventFilter(predicate.Or(
			predicate.GenerationChangedPredicate{},
			predicate.LabelChangedPredicate{},
			controllers.AnnotationChangedPredicate{},
		)).
		Complete(r)
}