/*
Copyright AppsCode Inc. and Contributors

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package v1alpha1

import (
	"context"
	"errors"
	"fmt"
	"strings"

	catalog "kubedb.dev/apimachinery/apis/catalog/v1alpha1"
	olddbapi "kubedb.dev/apimachinery/apis/kubedb/v1alpha2"
	opsapi "kubedb.dev/apimachinery/apis/ops/v1alpha1"
	opsutil "kubedb.dev/apimachinery/pkg/webhooks/ops"

	"gomodules.xyz/x/arrays"
	storagev1 "k8s.io/api/storage/v1"
	apierrors "k8s.io/apimachinery/pkg/api/errors"
	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/apimachinery/pkg/runtime/schema"
	"k8s.io/apimachinery/pkg/types"
	"k8s.io/apimachinery/pkg/util/mergepatch"
	"k8s.io/apimachinery/pkg/util/sets"
	"k8s.io/apimachinery/pkg/util/validation/field"
	meta_util "kmodules.xyz/client-go/meta"
	ctrl "sigs.k8s.io/controller-runtime"
	"sigs.k8s.io/controller-runtime/pkg/client"
	logf "sigs.k8s.io/controller-runtime/pkg/log"
	"sigs.k8s.io/controller-runtime/pkg/webhook"
	"sigs.k8s.io/controller-runtime/pkg/webhook/admission"
)

// SetupHazelcastOpsRequestWebhookWithManager registers the webhook for HazelcastOpsRequest in the manager.
func SetupHazelcastOpsRequestWebhookWithManager(mgr ctrl.Manager) error {
	return ctrl.NewWebhookManagedBy(mgr).For(&opsapi.HazelcastOpsRequest{}).
		WithValidator(&HazelcastOpsRequestCustomWebhook{mgr.GetClient()}).
		Complete()
}

type HazelcastOpsRequestCustomWebhook struct {
	DefaultClient client.Client
}

// log is for logging in this package.
var hzLog = logf.Log.WithName("hazelcast-opsrequest")

var _ webhook.CustomValidator = &HazelcastOpsRequestCustomWebhook{}

// ValidateCreate implements webhook.Validator so a webhook will be registered for the type
func (w *HazelcastOpsRequestCustomWebhook) ValidateCreate(ctx context.Context, obj runtime.Object) (admission.Warnings, error) {
	ops, ok := obj.(*opsapi.HazelcastOpsRequest)
	if !ok {
		return nil, fmt.Errorf("expected an HazelcastOpsRequest object but got %T", obj)
	}
	hzLog.Info("validate create", "name", ops.Name)
	return nil, w.validateCreateOrUpdate(ops)
}

// ValidateUpdate implements webhook.Validator so a webhook will be registered for the type
func (w *HazelcastOpsRequestCustomWebhook) ValidateUpdate(ctx context.Context, oldObj, newObj runtime.Object) (admission.Warnings, error) {
	ops, ok := newObj.(*opsapi.HazelcastOpsRequest)
	if !ok {
		return nil, fmt.Errorf("expected an HazelcastOpsRequest object but got %T", newObj)
	}
	hzLog.Info("validate update", "name", ops.Name)

	oldOps, ok := oldObj.(*opsapi.HazelcastOpsRequest)
	if !ok {
		return nil, fmt.Errorf("expected an HazelcastOpsRequest object but got %T", oldObj)
	}

	if err := validateHazelcastOpsRequest(ops, oldOps); err != nil {
		return nil, err
	}
	if err := w.validateCreateOrUpdate(ops); err != nil {
		return nil, err
	}

	if isOpsReqCompleted(ops.Status.Phase) && !isOpsReqCompleted(oldOps.Status.Phase) { // just completed
		var db olddbapi.Hazelcast
		err := w.DefaultClient.Get(context.TODO(), types.NamespacedName{Name: ops.Spec.DatabaseRef.Name, Namespace: ops.Namespace}, &db)
		if err != nil {
			return nil, err
		}
		return nil, resumeDatabase(w.DefaultClient, &db)
	}
	return nil, nil
}

func (w *HazelcastOpsRequestCustomWebhook) ValidateDelete(ctx context.Context, obj runtime.Object) (admission.Warnings, error) {
	return nil, nil
}

func validateHazelcastOpsRequest(req *opsapi.HazelcastOpsRequest, oldReq *opsapi.HazelcastOpsRequest) error {
	preconditions := meta_util.PreConditionSet{Set: sets.New[string]("spec")}
	_, err := meta_util.CreateStrategicPatch(oldReq, req, preconditions.PreconditionFunc()...)
	if err != nil {
		if mergepatch.IsPreconditionFailed(err) {
			return fmt.Errorf("%v.%v", err, preconditions.Error())
		}
		return err
	}
	return nil
}

func (w *HazelcastOpsRequestCustomWebhook) validateCreateOrUpdate(req *opsapi.HazelcastOpsRequest) error {
	if validType, _ := arrays.Contains(opsapi.HazelcastOpsRequestTypeNames(), string(req.Spec.Type)); !validType {
		return field.Invalid(field.NewPath("spec").Child("type"), req.Name,
			fmt.Sprintf("defined OpsRequestType %s is not supported, supported types for Hazelcast are %s", req.Spec.Type, strings.Join(opsapi.HazelcastOpsRequestTypeNames(), ", ")))
	}

	db, err := w.hasDatabaseRef(req)
	if err != nil {
		return field.Invalid(field.NewPath("spec").Child("databaseRef"), req.Name, err.Error())
	}

	var allErr field.ErrorList
	switch opsapi.HazelcastOpsRequestType(req.GetRequestType()) {
	case opsapi.HazelcastOpsRequestTypeRestart:
	case opsapi.HazelcastOpsRequestTypeHorizontalScaling:
		if err := w.validateHazelcastHorizontalScalingOpsRequest(req); err != nil {
			allErr = append(allErr, field.Invalid(field.NewPath("spec").Child("type").Child("HorizontalScaling"),
				req.Name,
				err.Error()))
		}
	case opsapi.HazelcastOpsRequestTypeReconfigure:
	case opsapi.HazelcastOpsRequestTypeUpdateVersion:
		if err := w.validateHazelcastUpdateVersionOpsRequest(db, req); err != nil {
			allErr = append(allErr, field.Invalid(field.NewPath("spec").Child("updateVersion"),
				req.Name,
				err.Error()))
		}
	case opsapi.HazelcastOpsRequestTypeVerticalScaling:
		if err := w.validateHazelcastVerticalScalingOpsRequest(req); err != nil {
			allErr = append(allErr, field.Invalid(field.NewPath("spec").Child("verticalScaling"),
				req.Name,
				err.Error()))
		}
	case opsapi.HazelcastOpsRequestTypeVolumeExpansion:
		if err := w.validateHazelcastVolumeExpansionOpsRequest(db, req); err != nil {
			allErr = append(allErr, field.Invalid(field.NewPath("spec").Child("volumeExpansion"),
				req.Name,
				err.Error()))
		}
	case opsapi.HazelcastOpsRequestTypeReconfigureTLS:
		if err := w.validateHazelcastReconfigureTLSOpsRequest(req); err != nil {
			allErr = append(allErr, field.Invalid(field.NewPath("spec").Child("type").Child("ReconfigureTLS"),
				req.Name,
				err.Error()))
		}
	case opsapi.HazelcastOpsRequestTypeRotateAuth:
		if err := w.validateHazelcastRotateAuthenticationOpsRequest(req); err != nil {
			allErr = append(allErr, field.Invalid(field.NewPath("spec").Child("authentication"),
				req.Name,
				err.Error()))
		}
	case opsapi.HazelcastOpsRequestTypeStorageMigration:
		if err := w.validateHazelcastStorageMigrationOpsRequest(req, db); err != nil {
			allErr = append(allErr, field.Invalid(field.NewPath("spec").Child("migration"),
				req.Name,
				err.Error()))
		}
	}

	if len(allErr) == 0 {
		return nil
	}
	return apierrors.NewInvalid(schema.GroupKind{Group: "hazelcastopsrequests.kubedb.com", Kind: "HazelcastOpsRequest"}, req.Name, allErr)
}

func (w *HazelcastOpsRequestCustomWebhook) hasDatabaseRef(req *opsapi.HazelcastOpsRequest) (*olddbapi.Hazelcast, error) {
	hz := &olddbapi.Hazelcast{}
	if err := w.DefaultClient.Get(context.TODO(), types.NamespacedName{
		Name:      req.GetDBRefName(),
		Namespace: req.GetNamespace(),
	}, hz); err != nil {
		return nil, fmt.Errorf("spec.databaseRef %s/%s, is invalid or not found", req.GetNamespace(), req.GetDBRefName())
	}
	return hz, nil
}

func (w *HazelcastOpsRequestCustomWebhook) validateHazelcastVerticalScalingOpsRequest(req *opsapi.HazelcastOpsRequest) error {
	verticalScalingSpec := req.Spec.VerticalScaling
	if verticalScalingSpec == nil {
		return errors.New("spec.verticalScaling nil not supported in VerticalScaling type")
	}
	if verticalScalingSpec.Hazelcast == nil {
		return errors.New("spec.verticalScaling.Hazelcast can't be empty at the same ops request")
	}

	return nil
}

func (w *HazelcastOpsRequestCustomWebhook) validateHazelcastHorizontalScalingOpsRequest(req *opsapi.HazelcastOpsRequest) error {
	horizontalScalingSpec := req.Spec.HorizontalScaling
	if horizontalScalingSpec == nil {
		return errors.New("spec.horizontalScaling nil not supported in VerticalScaling type")
	}
	if horizontalScalingSpec.Hazelcast == nil {
		return errors.New("spec.horizontalScalingSpec.Hazelcast can't be empty at the same ops request")
	}

	return nil
}

func (w *HazelcastOpsRequestCustomWebhook) validateHazelcastVolumeExpansionOpsRequest(db *olddbapi.Hazelcast, req *opsapi.HazelcastOpsRequest) error {
	volumeExpansionSpec := req.Spec.VolumeExpansion
	if volumeExpansionSpec == nil {
		return errors.New("spec.volumeExpansion nil not supported in VolumeExpansion type")
	}
	if volumeExpansionSpec.Hazelcast == nil {
		return errors.New("spec.volumeExpansion.Hazelcast can't be empty at the same ops request")
	}

	if err := opsutil.ValidateStorageExpansion(db.Spec.Storage, volumeExpansionSpec.Hazelcast, req.Status.Phase, "Hazelcast"); err != nil {
		return err
	}

	return nil
}

func (w *HazelcastOpsRequestCustomWebhook) validateHazelcastUpdateVersionOpsRequest(db *olddbapi.Hazelcast, req *opsapi.HazelcastOpsRequest) error {
	updateVersionSpec := req.Spec.UpdateVersion
	if updateVersionSpec == nil {
		return errors.New("spec.updateVersion nil not supported in UpdateVersion type")
	}

	yes, err := IsUpgradable(w.DefaultClient, catalog.ResourceKindHazelcastVersion, db.Spec.Version, updateVersionSpec.TargetVersion)
	if err != nil {
		return err
	}
	if !yes {
		return fmt.Errorf("upgrade from version %v to %v is not supported", db.Spec.Version, req.Spec.UpdateVersion.TargetVersion)
	}

	return nil
}

func (w *HazelcastOpsRequestCustomWebhook) validateHazelcastReconfigureTLSOpsRequest(req *opsapi.HazelcastOpsRequest) error {
	TLSSpec := req.Spec.TLS
	if TLSSpec == nil {
		return errors.New("spec.TLS nil not supported in ReconfigureTLS type")
	}
	configCount := 0
	if req.Spec.TLS.Remove {
		configCount++
	}
	if req.Spec.TLS.RotateCertificates {
		configCount++
	}
	if req.Spec.TLS.IssuerRef != nil || req.Spec.TLS.Certificates != nil {
		configCount++
	}

	if configCount == 0 {
		return errors.New("no reconfiguration is provided in TLS Spec")
	}

	if configCount > 1 {
		return errors.New("more than 1 field have assigned to spec.reconfigureTLS but at a time one is allowed to run one operation")
	}
	return nil
}

func (w *HazelcastOpsRequestCustomWebhook) validateHazelcastStorageMigrationOpsRequest(req *opsapi.HazelcastOpsRequest, db *olddbapi.Hazelcast) error {
	m := req.Spec.Migration
	if m == nil {
		return errors.New("spec.migration is required for StorageMigration type")
	}
	if m.StorageClassName == nil {
		return errors.New("spec.migration.storageClassName is required")
	}
	if req.Spec.Timeout == nil {
		return errors.New("spec.timeout is required for Storage Migration ops request, adjust timeout according to the size of your database")
	}
	if db.Spec.Storage == nil || db.Spec.Storage.StorageClassName == nil {
		return fmt.Errorf("db.Spec.Storage.StorageClassName can't be nil in the database yaml")
	}
	var newstorage, oldstorage storagev1.StorageClass
	if err := w.DefaultClient.Get(context.TODO(), types.NamespacedName{Name: *m.StorageClassName}, &newstorage); err != nil {
		if apierrors.IsNotFound(err) {
			return fmt.Errorf("storage class %s not found: %w", *m.StorageClassName, err)
		}
		return err
	}
	if err := w.DefaultClient.Get(context.TODO(), types.NamespacedName{Name: *db.Spec.Storage.StorageClassName}, &oldstorage); err != nil {
		return err
	}
	if *oldstorage.VolumeBindingMode == storagev1.VolumeBindingWaitForFirstConsumer {
		if *newstorage.VolumeBindingMode != storagev1.VolumeBindingWaitForFirstConsumer {
			return fmt.Errorf("volume binding mode should be WaitForFirstConsumer for %s storageClass", newstorage.Name)
		}
	}
	return nil
}

func (w *HazelcastOpsRequestCustomWebhook) validateHazelcastRotateAuthenticationOpsRequest(req *opsapi.HazelcastOpsRequest) error {
	authSpec := req.Spec.Authentication
	if authSpec != nil && authSpec.SecretRef != nil {
		if err := validateAuthSecretRef(context.TODO(), w.DefaultClient, req.Namespace, authSpec.SecretRef); err != nil {
			return err
		}
	}

	return nil
}
