package dataplane

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/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"
	rsconfig "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/dataplane/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("DataPlaneReconciler")

type DataPlaneReconciler struct {
	client.Client
	Log             logr.Logger
	Scheme          *runtime.Scheme
	Config          rsconfig.RootConfig
	TmplConfig      rsconfig.TemplatesConfig
	EventRecorder   record.EventRecorder
	dataPlaneRW     repository.DataPlaneReaderWriter
	vpcRW           repository.VPCReaderWriter
	internetRW      repository.InternetReaderWriter
	appBoxRW        repository.APPBoxReaderWriter
	nodePoolRW      repository.NodePoolReaderWriter
	vpcPeeringRW    repository.VPCPeeringReaderWriter
	pleZoneResolver task.PrivateLinkEndpointZoneResolver
}

func NewDataPlaneReconciler(
	client client.Client,
	log logr.Logger,
	scheme *runtime.Scheme,
	recorder record.EventRecorder,
	config rsconfig.RootConfig,
	tmplConfig rsconfig.TemplatesConfig,
) *DataPlaneReconciler {
	r := &DataPlaneReconciler{
		Client:        client,
		Log:           log,
		Scheme:        scheme,
		EventRecorder: recorder,
		Config:        config,
		TmplConfig:    tmplConfig,
		dataPlaneRW:   repository.NewDataPlaneReaderWriter(client),
		vpcRW:         repository.NewVPCReaderWriter(client),
		internetRW:    repository.NewInternetReaderWriter(client),
		appBoxRW:      repository.NewAPPBoxReaderWriter(client),
		nodePoolRW:    repository.NewNodePoolReaderWriter(client),
		vpcPeeringRW:  repository.NewVPCPeeringReaderWriter(client),
	}
	return r
}

func (r *DataPlaneReconciler) WithPrivateLinkEndpointZoneResolver(resolver task.PrivateLinkEndpointZoneResolver) *DataPlaneReconciler {
	r.pleZoneResolver = resolver
	return r
}

func (r *DataPlaneReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
	logger := r.Log.WithValues("DataPlane", req.NamespacedName)
	logger.Info("Reconciling RegionalServer DataPlane")

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

	dataPlane := new(v1alpha1.DataPlane)
	if err := r.dataPlaneRW.Get(ctx, req.NamespacedName, dataPlane); err != nil {
		if apierrors.IsNotFound(err) {
			logger.Info("DataPlane resource not found.")
			return ctrl.Result{}, nil
		}
		return ctrl.Result{}, fmt.Errorf("unable to get DataPlane resource %s: %w", req.NamespacedName, err)
	}
	if _, err := v1alpha1.EffectiveDataPlaneOwnershipMode(dataPlane.Spec.OwnershipMode); err != nil {
		return ctrl.Result{}, fmt.Errorf("invalid DataPlane ownership mode: %w", err)
	}
	// do nothing if the cr is paused
	if utils.IsPaused(dataPlane.GetObjectMeta()) {
		logger.Info("reconciliation is paused either through the pause annotation",
			"annotation", v1alpha1.AnnotationKeyReconciliationPaused)
		r.EventRecorder.Event(dataPlane, corev1.EventTypeWarning, "ReconciliationPaused", "reconciliation is paused through the annotation "+v1alpha1.AnnotationKeyReconciliationPaused)
		return ctrl.Result{}, nil
	}

	c, err := (&task.Context{
		Scheme:                          r.Scheme,
		Local:                           r.Client,
		Logger:                          logger,
		Config:                          r.Config,
		TmplConfig:                      r.TmplConfig,
		DataPlane:                       dataPlane,
		OriginalDataPlaneOwnershipMode:  dataPlane.Spec.OwnershipMode,
		DataPlaneRW:                     r.dataPlaneRW,
		VpcRW:                           r.vpcRW,
		InternetRW:                      r.internetRW,
		AppBoxRW:                        r.appBoxRW,
		NodePoolRW:                      r.nodePoolRW,
		VpcPeeringRW:                    r.vpcPeeringRW,
		PrivateLinkEndpointZoneResolver: r.pleZoneResolver,
	}).Default()
	if err != nil {
		return ctrl.Result{}, fmt.Errorf("unable to create task context: %w", err)
	}

	tasks := GetDataPlaneTasks(c)

	if dataPlane.DeletionTimestamp.IsZero() && isNotReadyDataPlane(dataPlane) {
		tasks = r.setHookOnTasks(tasks, c)

		// TODO: refactor tracing
		var span trace.Span
		ctx, span = tracer.Start(tracing.ExtractTraceContext(ctx, dataPlane), "DataPlane Reconcile")
		span.SetAttributes(
			attribute.String("dataplane", dataPlane.Name),
			attribute.String("namespace", dataPlane.Namespace),
		)
		defer func() { tracerutil.EndSpan(span, err) }()
	}
	d := deploy.NewDeployer(tasks, nil, logger)

	var res ctrl.Result
	if dataPlane.DeletionTimestamp.IsZero() {
		res, err = r.updateCreate(ctx, logger, c, d.Deploy(ctx))
	} else {
		if controllers.DeletionConfirmed(dataPlane) {
			dataPlane.Status.Phase = v1alpha1.DataPlanePhaseDeleting
			if err := r.dataPlaneRW.UpdateStatus(ctx, dataPlane); err != nil {
				return ctrl.Result{}, fmt.Errorf("failed to update dataplane status: %w", err)
			}
			res, err = r.updateDelete(ctx, logger, c, d.Destroy(ctx))
		} else {
			logger.Info("waiting for dataplane deletion to be confirmed")
			return ctrl.Result{}, fmt.Errorf("dataplane deletion is not confirmed")
		}
	}
	if err == nil {
		r.EventRecorder.Event(dataPlane, corev1.EventTypeNormal, "ReconcileSuccess", "")
	} else {
		r.EventRecorder.Event(dataPlane, corev1.EventTypeWarning, "ReconcileFail", err.Error())
	}
	return res, err
}

func isNotReadyDataPlane(dataPlane *v1alpha1.DataPlane) bool {
	return dataPlane.Status.Phase != v1alpha1.DataPlanePhaseActive &&
		dataPlane.Status.Phase != v1alpha1.DataPlanePhaseDeleting
}

func (r *DataPlaneReconciler) setHookOnTasks(tasks []deploy.Task, c *task.Context) []deploy.Task {
	hook := func(ctc context.Context, task deploy.Task) {
		name := task.Name()
		passTimeKey := utils.GenTaskFirstPastAnnotationKey(name)
		_, ok := c.DataPlane.Annotations[passTimeKey]
		if ok {
			return
		}
		if c.DataPlane.Annotations == nil {
			c.DataPlane.Annotations = map[string]string{}
		}
		c.DataPlane.Annotations[passTimeKey] = time.Now().Format(time.RFC3339)
		log.FromContext(ctc).Info("pass task when creating dataplane", "task", name)
	}
	for idx, t := range tasks {
		tasks[idx] = deploy.NewTaskWraper(t, hook, tracer)
	}
	return tasks
}

func (r *DataPlaneReconciler) updateCreate(ctx context.Context, logger logr.Logger, t *task.Context, results []deploy.Result) (ctrl.Result, error) {
	res, err, retriableErrs := deploy.MinRequeue(results)
	if err != nil {
		logger.Info("deploy create encounters error", "unretriable", err)
		t.DataPlane.Status.Phase = v1alpha1.DataPlanePhaseFailed
		t.DataPlane.Status.Reason = err.Error()
	} else if retriableErrs != nil {
		// for retriable error, just log and update reason, no need to change status
		t.DataPlane.Status.Reason = retriableErrs.Error()
		logger.Info("deploy create encounters error", "retriable", retriableErrs)
	} else {
		t.DataPlane.Status.Phase = v1alpha1.DataPlanePhaseActive
		t.DataPlane.Status.Reason = ""
	}

	if e := r.updateDataPlane(ctx, logger, t.DataPlane, t.OriginalDataPlaneOwnershipMode); e != nil {
		return res, fmt.Errorf("failed to update dataplane: %w", e)
	}
	return res, err
}

func (r *DataPlaneReconciler) updateDataPlane(
	ctx context.Context,
	logger logr.Logger,
	dataPlane *v1alpha1.DataPlane,
	originalOwnershipMode v1alpha1.DataPlaneOwnershipMode,
) error {
	if err := v1alpha1.ValidateDataPlaneOwnershipModeUpdate(
		originalOwnershipMode,
		dataPlane.Spec.OwnershipMode,
	); err != nil {
		return err
	}
	dataPlaneStatus := dataPlane.Status.DeepCopy()
	if err := r.dataPlaneRW.Update(ctx, dataPlane); err != nil {
		logger.Error(err, "failed to update dataplane")
		return err
	}
	dataPlane.Status = *dataPlaneStatus
	if err := r.dataPlaneRW.UpdateStatus(ctx, dataPlane); err != nil && !apierrors.IsNotFound(err) {
		logger.Error(err, "failed to update dataplane status")
		return err
	}
	return nil
}

func (r *DataPlaneReconciler) updateDelete(ctx context.Context, logger logr.Logger, t *task.Context, results []deploy.Result) (ctrl.Result, error) {
	res, err, retriableErr := deploy.MinRequeue(results)
	if err != nil {
		t.DataPlane.Status.Reason = err.Error()
		logger.Info("deploy delete encounters error", "unretriable", err)
	} else if retriableErr != nil {
		t.DataPlane.Status.Reason = retriableErr.Error()
		logger.Info("deploy delete encounters error", "retriable", retriableErr)
	} else {
		logger.Info("deploy delete successfully, remove finalizer")
		controllerutil.RemoveFinalizer(t.DataPlane, v1alpha1.Finalizer)
	}

	if e := r.updateDataPlane(ctx, logger, t.DataPlane, t.OriginalDataPlaneOwnershipMode); e != nil {
		return res, fmt.Errorf("failed to update dataplane: %w", e)
	}
	return res, err
}

func (r *DataPlaneReconciler) SetupWithManager(mgr ctrl.Manager, pds ...predicate.Predicate) error {
	return ctrl.NewControllerManagedBy(mgr).
		For(&v1alpha1.DataPlane{}, builder.WithPredicates(pds...)).
		WithOptions(controller.Options{RateLimiter: k8s.RetryLimiter, MaxConcurrentReconciles: 5}).
		WithEventFilter(predicate.Or(
			predicate.GenerationChangedPredicate{},
			predicate.LabelChangedPredicate{},
			controllers.AnnotationChangedPredicate{},
		)).
		Complete(r)
}