package key

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/key/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("KeyReconciler")

type Reconciler struct {
	client.Client
	Log           logr.Logger
	Scheme        *runtime.Scheme
	EventRecorder record.EventRecorder
	KeyRW         repository.KeyReaderWriter
	Config        config.RootConfig
}

func NewReconciler(client client.Client, log logr.Logger, scheme *runtime.Scheme, recorder record.EventRecorder, conf config.RootConfig) *Reconciler {
	return &Reconciler{
		Client:        client,
		Log:           log,
		Scheme:        scheme,
		EventRecorder: recorder,
		KeyRW:         repository.NewKeyReaderWriter(client),
		Config:        conf,
	}
}

//+kubebuilder:rbac:groups=dedicated.regionalserver.tidbcloud.com,resources=keys,verbs=get;list;watch;create;update;patch;delete
//+kubebuilder:rbac:groups=dedicated.regionalserver.tidbcloud.com,resources=keys/status,verbs=get;update;patch
//+kubebuilder:rbac:groups=dedicated.regionalserver.tidbcloud.com,resources=keys/finalizers,verbs=update
//+kubebuilder:rbac:groups=kms.aws.upbound.io,resources=keys,verbs=get;list;watch;create;update;patch;delete
//+kubebuilder:rbac:groups=kms.aws.upbound.io,resources=aliases,verbs=get;list;watch;create;update;patch;delete
//+kubebuilder:rbac:groups=kms.alibabacloud.crossplane.io,resources=keys,verbs=get;list;watch;create;update;patch;delete

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

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

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

	if utils.IsPaused(key.GetObjectMeta()) {
		logger.Info("reconciliation is paused either through the pause annotation",
			"annotation", v1alpha1.AnnotationKeyReconciliationPaused,
			"key", req.NamespacedName.String(),
		)
		r.EventRecorder.Event(&key, corev1.EventTypeWarning, "ReconciliationPaused", "reconciliation is paused through the annotation "+v1alpha1.AnnotationKeyReconciliationPaused)
		return ctrl.Result{}, nil
	}

	providerType := key.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, key.DeepCopy(), namer.NewNamer()).Client(),
		DataPlaneR: repository.NewDataPlaneReader(r.Client),
		AppBoxR:    repository.NewAPPBoxReader(r.Client),
		Logger:     logger,
		Key:        &key,
		Config:     r.Config,
	}).Default()
	if err != nil {
		return ctrl.Result{}, fmt.Errorf("failed to create a new context: %v", err)
	}

	tasks := GetKeyTasks(r, c)
	if key.DeletionTimestamp.IsZero() && isNotReadyKey(&key) {
		tasks = r.setHookOnTasks(tasks, c)

		var span trace.Span
		ctx, span = tracer.Start(tracing.ExtractTraceContext(ctx, &key), "Key Reconcile")
		span.SetAttributes(
			attribute.String("key", key.Name),
			attribute.String("namespace", key.Namespace),
			attribute.String("provider", key.Spec.Provider),
		)
		defer func() { tracerutil.EndSpan(span, err) }()
	}

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

	var res ctrl.Result

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

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

	return res, err
}

func isNotReadyKey(key *v1alpha1.Key) bool {
	return key.Status.Phase != v1alpha1.KeyPhaseActive &&
		key.Status.Phase != v1alpha1.KeyPhaseDeleting
}

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

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

func (r *Reconciler) updateCreate(ctx context.Context, log logr.Logger, t *task.Context, results []deploy.Result) (ctrl.Result, error) {
	if keyID := t.Key.Status.ID; keyID != "" {
		log = log.WithValues("keyID", keyID)
	}
	res, err, retriableErrs := deploy.MinRequeue(results)
	if err == nil && retriableErrs == nil {
		log.Info("Mark Key as active")
		t.Key.Status.Phase = v1alpha1.KeyPhaseActive
	}

	if err != nil {
		log.Error(err, "UpdateCreate Key")
		t.Key.Status.Phase = v1alpha1.KeyPhaseFailed
	}

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

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

	return res, err
}

func updateKey(ctx context.Context, rw repository.KeyReaderWriter, key *v1alpha1.Key) error {
	keyStatus := key.Status.DeepCopy()

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

func (r *Reconciler) 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.Key, v1alpha1.Finalizer)
	}

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

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

	return res, err
}

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