package loadbalancer

import (
	"context"
	"fmt"
	"time"

	"github.com/go-logr/logr"
	"github.com/pingcap/errors"
	"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/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/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/loadbalancer/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("LoadBalancerReconciler")

type LoadBalancerReconciler struct {
	client.Client
	Log            logr.Logger
	Scheme         *runtime.Scheme
	Manager        *controllers.Manager
	LoadBalancerRW repository.LoadBalancerReaderWriter
	DataPlaneR     repository.DataPlaneReader
	APPBoxR        repository.APPBoxReader
	VpcR           repository.VPCReader
	awsCli         aws.Client
	aliyunCli      aliyun.Client
	EventRecorder  record.EventRecorder
	Config         config.RootConfig
}

func NewLoadBalancerReconciler(client client.Client, log logr.Logger,
	scheme *runtime.Scheme, recorder record.EventRecorder,
	ctlManager *controllers.Manager,
	awsCli aws.Client,
	aliyunCli aliyun.Client,
	conf config.RootConfig) *LoadBalancerReconciler {
	return &LoadBalancerReconciler{
		Client:         client,
		Log:            log,
		Scheme:         scheme,
		Manager:        ctlManager,
		LoadBalancerRW: repository.NewLoadBalancerReaderWriter(client),
		DataPlaneR:     repository.NewDataPlaneReader(client),
		APPBoxR:        repository.NewAPPBoxReader(client),
		VpcR:           repository.NewVPCReader(client),
		EventRecorder:  recorder,
		awsCli:         awsCli,
		aliyunCli:      aliyunCli,
		Config:         conf,
	}
}

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

// Reconcile is part of the main kubernetes reconciliation loop which aims to
// move the current state of the LoadBalancer closer to the desired state.
func (r *LoadBalancerReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
	logger := r.Log.WithValues("LoadBalancer", req.NamespacedName)
	logger.Info("Reconciling RegionalServer LoadBalancer")
	r.EventRecorder.Event(&v1alpha1.LoadBalancer{}, corev1.EventTypeNormal, "ReconcileStart", "")

	start := time.Now()
	defer func() {
		logger.Info("Finish RegionalServer LoadBalancer reconcile", "take", time.Since(start))
	}()

	var loadBalancer v1alpha1.LoadBalancer
	if err := r.Client.Get(ctx, req.NamespacedName, &loadBalancer); err != nil {
		if apierrors.IsNotFound(err) {
			logger.Info("RegionalServer LoadBalancer not found")
			return ctrl.Result{}, nil
		}
		return ctrl.Result{}, fmt.Errorf("unable to get regionalserver LoadBalancer %s: %v", req.NamespacedName, err)
	}
	dataPlaneObj, appBoxObj, vpcObj, err := r.getDataPlaneAppBoxAndVPC(ctx, loadBalancer.Spec.DataPlane.Namespace, loadBalancer.Spec.DataPlane.Name)
	if err != nil {
		return ctrl.Result{}, fmt.Errorf("unable to get regionalserver appbox %s: %v", loadBalancer.Name, err)
	}
	controllers.EnsureDataPlaneIDLabel(&loadBalancer, dataPlaneObj.Name)
	c, err := (&task.Context{
		Local:        k8s.NewMutClientWithOwner(r.Client, loadBalancer.DeepCopy(), namer.NewNamer()).Client(),
		Logger:       logger,
		LoadBalancer: &loadBalancer,
		DataPlane:    dataPlaneObj,
		Manager:      r.Manager,
		Config:       r.Config,
		AppBox:       appBoxObj,
		VPC:          vpcObj,
	}).Default()
	if err != nil {
		return ctrl.Result{}, fmt.Errorf("failed to create a new context: %v", err)
	}
	tasks := GetLoadBalancerTasks(c, r)
	if loadBalancer.DeletionTimestamp.IsZero() {
		tasks = r.setHookOnTasks(tasks, c)
		var span trace.Span
		ctx, span = tracer.Start(tracing.ExtractTraceContext(ctx, &loadBalancer), "LoadBalancer Reconcile")
		span.SetAttributes(
			attribute.String("loadbalancer", loadBalancer.Name),
			attribute.String("namespace", loadBalancer.Namespace),
		)
		defer func() { tracerutil.EndSpan(span, err) }()
	}

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

	var res ctrl.Result

	if loadBalancer.DeletionTimestamp.IsZero() {
		res, err = r.updateCreate(ctx, logger, c, d.Deploy(ctx))
	} else {
		if controllers.DeletionConfirmed(&loadBalancer) {
			loadBalancer.Status.Phase = v1alpha1.LoadBalancerPhaseDeleting
			if err := r.LoadBalancerRW.UpdateStatus(ctx, &loadBalancer); 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 loadbalancer deletion to be confirmed")
			return ctrl.Result{}, fmt.Errorf("loadbalancer deletion is not confirmed")
		}
	}

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

	return res, err
}

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

func (r *LoadBalancerReconciler) updateCreate(ctx context.Context, log logr.Logger,
	t *task.Context, results []deploy.Result) (ctrl.Result, error) {
	res, errs, retriableErrs := deploy.MinRequeue(results)
	if errs != nil || retriableErrs != nil {
		log.Info("deploy met error",
			"errs", errs, "retriableErrs", retriableErrs)
	}
	endpointStatus := t.LoadBalancer.Status.DeepCopy()
	if err := r.LoadBalancerRW.Update(ctx, t.LoadBalancer); err != nil {
		r.EventRecorder.Event(t.LoadBalancer, corev1.EventTypeWarning, "ReconcileFailed", err.Error())
		return res, err
	}
	t.LoadBalancer.Status = *endpointStatus
	if err := r.LoadBalancerRW.UpdateStatus(ctx, t.LoadBalancer); err != nil {
		r.EventRecorder.Event(t.LoadBalancer, corev1.EventTypeWarning, "ReconcileFailed", err.Error())
		return res, err
	}
	return res, errs
}

func (r *LoadBalancerReconciler) 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.LoadBalancer, v1alpha1.Finalizer)
	}

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

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

	return res, err
}

func (r *LoadBalancerReconciler) getDataPlaneAppBoxAndVPC(ctx context.Context, ns, dataplaneName string) (*v1alpha1.DataPlane, *v1alpha1.APPBox, *v1alpha1.VPC, error) {
	dataPlaneObj := &v1alpha1.DataPlane{}
	if err := r.DataPlaneR.Get(ctx,
		client.ObjectKey{Name: dataplaneName,
			Namespace: ns},
		dataPlaneObj); err != nil {
		return nil, nil, nil, errors.Annotatef(err, "failed to get dataplane:%s", dataplaneName)
	}

	appBoxObj := new(v1alpha1.APPBox)
	objKey := client.ObjectKey{
		Name:      dataPlaneObj.Status.AppBox.Name,
		Namespace: dataPlaneObj.Status.AppBox.Namespace,
	}
	if err := r.APPBoxR.Get(ctx, objKey, appBoxObj); err != nil {
		return nil, nil, nil, errors.Annotatef(err, "failed to get appbox:%s", dataPlaneObj.Status.AppBox.Name)
	}
	if appBoxObj.Spec.VPCRef == nil {
		return nil, nil, nil, fmt.Errorf("appbox %s:  vpc ref is nil", dataPlaneObj.Status.AppBox.Name)
	}
	vpcObj := new(v1alpha1.VPC)
	if err := r.VpcR.Get(ctx, client.ObjectKey{
		Namespace: appBoxObj.Spec.VPCRef.Namespace,
		Name:      appBoxObj.Spec.VPCRef.Name,
	}, vpcObj); err != nil {
		return nil, nil, nil, errors.Annotatef(err, "failed to get vpc:%s", appBoxObj.Spec.VPCRef.Name)
	}
	return dataPlaneObj, appBoxObj, vpcObj, nil
}

func (r *LoadBalancerReconciler) SetupWithManager(mgr ctrl.Manager, pds ...predicate.Predicate) error {
	if err := mgr.GetFieldIndexer().IndexField(context.Background(), &v1alpha1.LoadBalancer{}, controllers.DataPlaneNameField, func(o client.Object) []string {
		i := o.(*v1alpha1.LoadBalancer)
		return []string{i.Spec.DataPlane.Name}
	}); err != nil {
		return err
	}
	// GenerationChangedPredicate, LabelChanedPredicate and AnnotationChanedPredicate
	// are used to ignore status changes
	return ctrl.NewControllerManagedBy(mgr).
		For(&v1alpha1.LoadBalancer{}, builder.WithPredicates(pds...)).
		WithOptions(controller.Options{RateLimiter: k8s.RetryLimiter, MaxConcurrentReconciles: 5}).
		WithEventFilter(predicate.Or(
			predicate.GenerationChangedPredicate{},
			predicate.LabelChangedPredicate{},
			controllers.AnnotationChangedPredicate{},
		)).
		Complete(r)
}