package internet

import (
	"context"
	"fmt"
	"time"

	"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/go-logr/logr"
	"github.com/tidbcloud/infra-provider/pkg/cloud/gcp"
	"github.com/tidbcloud/infra-provider/pkg/deploy"
	"github.com/tidbcloud/infra-provider/pkg/k8s"
	"github.com/tidbcloud/infra-provider/pkg/o11y/tracing"
	tracerutil "github.com/tidbcloud/infra-provider/pkg/tracer"
	"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/internet/task"
	"github.com/tidbcloud/infra-provider/regional-server/pkg/resourcemanager/appbox"
	"github.com/tidbcloud/infra-provider/regional-server/pkg/resourcemanager/approute"
	"github.com/tidbcloud/infra-provider/regional-server/pkg/resourcemanager/internet"
	"github.com/tidbcloud/infra-provider/regional-server/pkg/resourcemanager/vpc"
)

var (
	tracer = otel.Tracer("InternetReconciler")
)

type InternetReconciler struct {
	client.Client
	Log           logr.Logger
	Scheme        *runtime.Scheme
	EventRecorder record.EventRecorder
	InternetRW    internet.InternetReaderWriter
	VPCR          vpc.VPCReader
	APPBoxR       appbox.APPBoxReader
	APPRouteRW    approute.APPRouteReaderWriter
	Config        config.RootConfig
	GCPCli        gcp.Client
}

func NewInternetReconciler(
	client client.Client,
	log logr.Logger,
	scheme *runtime.Scheme,
	eventRecorder record.EventRecorder,
	conf config.RootConfig,
	gcpCli gcp.Client,
) *InternetReconciler {
	return &InternetReconciler{
		Client:        client,
		Log:           log,
		Scheme:        scheme,
		EventRecorder: eventRecorder,
		InternetRW:    internet.NewInternetReaderWriter(client),
		VPCR:          vpc.NewVPCReader(client),
		APPBoxR:       appbox.NewAPPBoxReader(client),
		APPRouteRW:    approute.NewAPPRouteReaderWriter(client),
		Config:        conf,
		GCPCli:        gcpCli,
	}
}

//+kubebuilder:rbac:groups=dedicated.regionalserver.tidbcloud.com,resources=internet,verbs=get;list;watch;create;update;patch;delete
//+kubebuilder:rbac:groups=dedicated.regionalserver.tidbcloud.com,resources=internet/status,verbs=get;update;patch
//+kubebuilder:rbac:groups=dedicated.regionalserver.tidbcloud.com,resources=internet/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 *InternetReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
	log := r.Log.WithValues("Internet", req.NamespacedName)
	log.Info("Reconciling RegionalServer Internet")

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

	var internet v1alpha1.Internet
	if err := r.InternetRW.Get(ctx, req.NamespacedName, &internet); err != nil {
		if apierrors.IsNotFound(err) {
			log.Info("Internet resource not found.")
			return ctrl.Result{}, nil
		}
		return ctrl.Result{}, fmt.Errorf("unable to get internet resource %s: %w", req.NamespacedName, err)
	}
	// do nothing if the cr is paused
	if utils.IsPaused(internet.GetObjectMeta()) {
		log.Info("reconciliation is paused either through the pause annotation",
			"annotation", v1alpha1.AnnotationKeyReconciliationPaused,
			"internet", req.NamespacedName.String(),
		)
		r.EventRecorder.Event(&internet, "ReconciliationPaused", "reconciliation is paused through the pause annotation", v1alpha1.AnnotationKeyReconciliationPaused)
		return ctrl.Result{}, nil
	}

	providerType := internet.Spec.Provider
	if providerType != r.Config.Provider {
		log.Info("Mismatched provider", "expect", r.Config.Provider, "got", providerType)
		return ctrl.Result{}, nil
	}

	vpc := &v1alpha1.VPC{}
	if err := r.VPCR.Get(ctx, types.NamespacedName{Name: internet.Spec.VPCRef.Name, Namespace: internet.Spec.VPCRef.Namespace}, vpc); err != nil {
		return ctrl.Result{}, fmt.Errorf("unable to get vpc %s: %w", internet.Spec.VPCRef.Name, err)
	}

	c, err := (&task.Context{
		Local:      r.Client,
		Logger:     log,
		Internet:   &internet,
		VPC:        vpc,
		InternetRW: r.InternetRW,
		VPCR:       r.VPCR,
		APPBoxR:    r.APPBoxR,
		APPRouteRW: r.APPRouteRW,
		Config:     r.Config,
	}).Default()
	if err != nil {
		return ctrl.Result{}, fmt.Errorf("unable to create task context: %w", err)
	}

	tasks := GetInternetTasks(r, c)
	if internet.DeletionTimestamp.IsZero() && isNotReadyInternet(&internet) {
		tasks = r.setHookOnTasks(tasks, c)

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

	var res ctrl.Result
	if internet.DeletionTimestamp.IsZero() {
		res, err = r.updateCreate(ctx, log, c, d.Deploy(ctx))
	} else {
		internet.Status.Phase = v1alpha1.InternetPhaseDeleting
		if err := r.InternetRW.UpdateStatus(ctx, &internet); err != nil {
			return ctrl.Result{}, fmt.Errorf("failed to update internet status: %w", err)
		}
		res, err = r.updateDelete(ctx, log, c, d.Destroy(ctx))
	}
	if err == nil {
		r.EventRecorder.Event(&internet, corev1.EventTypeNormal, "ReconcileSuccess", "")
	} else {
		r.EventRecorder.Event(&internet, corev1.EventTypeWarning, "ReconcileFail", err.Error())
	}

	return res, err
}

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

		age := time.Since(c.Internet.CreationTimestamp.Time)
		c.Internet.Annotations[passTimeKey] = age.String()
		log.FromContext(ctx).Info("pass task when creating internet", "task", name, "age", age.String())
	}

	for idx, task := range tasks {
		tasks[idx] = deploy.NewTaskWraper(task, hook, tracer)
	}

	return tasks
}

func isNotReadyInternet(internet *v1alpha1.Internet) bool {
	return internet.Status.Phase != v1alpha1.InternetPhaseActive &&
		internet.Status.Phase != v1alpha1.InternetPhaseReadyForDelete &&
		internet.Status.Phase != v1alpha1.InternetPhaseDeleting
}

func (r *InternetReconciler) updateCreate(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 {
		log.Info("Mark Internet as active")
		if t.Internet.Status.Phase != v1alpha1.InternetPhaseReadyForDelete {
			t.Internet.Status.Phase = v1alpha1.InternetPhaseActive
			t.Internet.Status.Reason = ""
		}
	}

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

	if e := updateInternet(ctx, t.InternetRW, t.Internet); e != nil {
		log.Error(e, "failed to update internet")
		return res, fmt.Errorf("failed to update internet: %v", e)
	}
	return res, err
}

func updateInternet(ctx context.Context, rw internet.InternetReaderWriter, internet *v1alpha1.Internet) error {
	internetStatus := internet.Status.DeepCopy()
	if internet.Status.VPCID != "" {
		internet.Labels[v1alpha1.VPCIDKey] = internet.Status.VPCID
	}
	if err := rw.Update(ctx, internet); err != nil {
		return err
	}

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

func (r *InternetReconciler) 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.Internet, v1alpha1.Finalizer)
	}

	if e := r.InternetRW.Update(ctx, t.Internet); e != nil {
		log.Error(e, "failed to update internet")
		return res, fmt.Errorf("failed to update internet: %v", e)
	}
	if retriableErrs != nil {
		log.Error(err, "requeue for updateDelete", "after", res.RequeueAfter.String())
	}

	return res, err
}

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