package v1

import (
	"context"
	"fmt"
	"regexp"

	"github.com/google/go-cmp/cmp"

	"k8s.io/apimachinery/pkg/api/resource"
	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/apimachinery/pkg/util/validation/field"
	ctrl "sigs.k8s.io/controller-runtime"
	logf "sigs.k8s.io/controller-runtime/pkg/log"
	"sigs.k8s.io/controller-runtime/pkg/webhook"
	"sigs.k8s.io/controller-runtime/pkg/webhook/admission"
)

var (
	targetTablePatternRegexp = regexp.MustCompile("^(`.+`)\\.(`.+`)|(.+)\\.(.+)$")
)

// log is for logging in this package.
var importlog = logf.Log.WithName("import-resource")

func (r *Import) setupWebhookWithManager(mgr ctrl.Manager) error {
	return ctrl.NewWebhookManagedBy(mgr).
		For(r).
		Complete()
}

func ParseTargetTable(targetTable string) (string, string, error) {
	var result []string

	for _, i := range targetTablePatternRegexp.FindStringSubmatch(targetTable) {
		if i != "" {
			result = append(result, i)
		}
	}

	if len(result) != 3 {
		return "", "", fmt.Errorf("Target table pattern does not match the requirement, please refer the document.")
	}

	return result[1], result[2], nil
}

// EDIT THIS FILE!  THIS IS SCAFFOLDING FOR YOU TO OWN!

//+kubebuilder:webhook:path=/mutate-cloud-pingcap-com-v1-import,mutating=true,failurePolicy=fail,sideEffects=None,groups=cloud.pingcap.com,resources=imports,verbs=create;update,versions=v1,name=mimport.kb.io,admissionReviewVersions={v1,v1beta1}

var _ webhook.Defaulter = &Import{}

// Default implements webhook.Defaulter so a webhook will be registered for the type
func (r *Import) Default() {
	if r.Labels == nil {
		r.Labels = map[string]string{}
	}

	// skip validate cluster exist for migrated resources
	if isMigratedResource(r.Annotations) {
		return
	}

	var c Cluster
	err := webhookClient.Get(context.TODO(), r.GetClusterRef(), &c)
	if err != nil {
		importlog.Error(err, "error get cluster of import, forward to validation")
		return
	}

	r.Labels[ProviderTypeLabel] = c.GetProviderType()
	r.Labels[RegionLabel] = c.Labels[RegionLabel]

	// TODO(user): fill in your defaulting logic, like for bucket URL?.
}

// TODO(user): change verbs to "verbs=create;update;delete" if you want to enable deletion validation.
//+kubebuilder:webhook:path=/validate-cloud-pingcap-com-v1-import,mutating=false,failurePolicy=fail,sideEffects=None,groups=cloud.pingcap.com,resources=imports,verbs=create;update,versions=v1,name=vimport.kb.io,admissionReviewVersions={v1,v1beta1}

var _ webhook.Validator = &Import{}

// ValidateCreate implements webhook.Validator so a webhook will be registered for the type
func (r *Import) ValidateCreate() (admission.Warnings, error) {
	importlog.V(4).Info("validate create", "name", r.Name)

	var allErrs field.ErrorList
	if errs := r.validateSpec(); errs != nil {
		allErrs = append(allErrs, errs...)
	}
	if err := validateProviderLabelForClusterSubresource(r); err != nil {
		allErrs = append(allErrs, err)
	}

	return nil, invalidOrNil(allErrs, r)
}

// ValidateUpdate implements webhook.Validator so a webhook will be registered for the type
func (r *Import) ValidateUpdate(old runtime.Object) (admission.Warnings, error) {
	importlog.V(4).Info("validate update", "name", r.Name)

	var allErrs field.ErrorList
	oldI := old.(*Import)

	if !cmp.Equal(r.Spec, oldI.Spec) {
		allErrs = append(allErrs, field.Invalid(field.NewPath("spec"), r.Spec, "spec is immutable"))
	}

	if r.GetLabels()[ProviderTypeLabel] != oldI.GetLabels()[ProviderTypeLabel] {
		allErrs = append(allErrs, field.Invalid(field.NewPath("metadata").Child("labels"), r.GetLabels()[ProviderTypeLabel],
			fmt.Sprintf("%s label is immutable", ProviderTypeLabel)))
	}

	return nil, invalidOrNil(allErrs, r)
}

// ValidateDelete implements webhook.Validator so a webhook will be registered for the type
func (r *Import) ValidateDelete() (admission.Warnings, error) {
	return nil, nil
}

func (r *Import) validateSpec() field.ErrorList {
	var allErrs field.ErrorList
	fld := field.NewPath("spec")
	var c Cluster
	var n Network

	// skip validate cluster exist for migrated resources
	if !isMigratedResource(r.Annotations) {
		err := webhookClient.Get(context.TODO(), r.GetClusterRef(), &c)
		if err != nil {
			allErrs = append(allErrs, field.Invalid(fld.Child("clusterName"), r.Spec.ClusterName,
				fmt.Sprintf("cluster not found, err: %s", err.Error())))
			return allErrs
		}
		err = webhookClient.Get(context.TODO(), c.GetNetworkRef(), &n)
		if err != nil {
			allErrs = append(allErrs, field.Invalid(fld.Child("clusterName"), r.Spec.ClusterName,
				fmt.Sprintf("network not found from the cluster: %s", err)))
			return allErrs
		}
	}

	if r.Spec.StorageRequest != "" {
		_, err := resource.ParseQuantity(r.Spec.StorageRequest)
		if err != nil {
			allErrs = append(allErrs, field.Invalid(fld.Child("storageRequest"), r.Spec.StorageRequest,
				fmt.Sprintf("bad quantity format, err: %s", err.Error())))
			return allErrs
		}
	}

	return allErrs
}