/*
Copyright 2016 The Kubernetes Authors.
Copyright 2020 Authors of Arktos - file modified.

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 validation

import (
	"fmt"
	"strings"

	"k8s.io/apimachinery/pkg/api/validation"
	"k8s.io/apimachinery/pkg/api/validation/path"
	utilvalidation "k8s.io/apimachinery/pkg/util/validation"
	"k8s.io/apimachinery/pkg/util/validation/field"

	"k8s.io/kube-aggregator/pkg/apis/apiregistration"
)

// ValidateAPIService validates that the APIService is correctly defined.
func ValidateAPIService(apiService *apiregistration.APIService) field.ErrorList {
	requiredName := apiService.Spec.Version + "." + apiService.Spec.Group

	allErrs := validation.ValidateObjectMeta(&apiService.ObjectMeta, true, false,
		func(name string, prefix bool) []string {
			if minimalFailures := path.IsValidPathSegmentName(name); len(minimalFailures) > 0 {
				return minimalFailures
			}
			// the name *must* be version.group
			if name != requiredName {
				return []string{fmt.Sprintf("must be `spec.version+\".\"+spec.group`: %q", requiredName)}
			}

			return []string{}
		},
		field.NewPath("metadata"))

	// in this case we allow empty group
	if len(apiService.Spec.Group) == 0 && apiService.Spec.Version != "v1" {
		allErrs = append(allErrs, field.Required(field.NewPath("spec", "group"), "only v1 may have an empty group and it better be legacy kube"))
	}
	if len(apiService.Spec.Group) > 0 {
		for _, errString := range utilvalidation.IsDNS1123Subdomain(apiService.Spec.Group) {
			allErrs = append(allErrs, field.Invalid(field.NewPath("spec", "group"), apiService.Spec.Group, errString))
		}
	}

	for _, errString := range utilvalidation.IsDNS1035Label(apiService.Spec.Version) {
		allErrs = append(allErrs, field.Invalid(field.NewPath("spec", "version"), apiService.Spec.Version, errString))
	}

	if apiService.Spec.GroupPriorityMinimum <= 0 || apiService.Spec.GroupPriorityMinimum > 20000 {
		allErrs = append(allErrs, field.Invalid(field.NewPath("spec", "groupPriorityMinimum"), apiService.Spec.GroupPriorityMinimum, "must be positive and less than 20000"))
	}
	if apiService.Spec.VersionPriority <= 0 || apiService.Spec.VersionPriority > 1000 {
		allErrs = append(allErrs, field.Invalid(field.NewPath("spec", "versionPriority"), apiService.Spec.VersionPriority, "must be positive and less than 1000"))
	}

	if apiService.Spec.Service == nil {
		if len(apiService.Spec.CABundle) != 0 {
			allErrs = append(allErrs, field.Invalid(field.NewPath("spec", "caBundle"), fmt.Sprintf("%d bytes", len(apiService.Spec.CABundle)), "local APIServices may not have a caBundle"))
		}
		if apiService.Spec.InsecureSkipTLSVerify {
			allErrs = append(allErrs, field.Invalid(field.NewPath("spec", "insecureSkipTLSVerify"), apiService.Spec.InsecureSkipTLSVerify, "local APIServices may not have insecureSkipTLSVerify"))
		}
		return allErrs
	}

	if len(apiService.Spec.Service.Namespace) == 0 {
		allErrs = append(allErrs, field.Required(field.NewPath("spec", "service", "namespace"), ""))
	}
	if len(apiService.Spec.Service.Name) == 0 {
		allErrs = append(allErrs, field.Required(field.NewPath("spec", "service", "name"), ""))
	}
	if errs := utilvalidation.IsValidPortNum(int(apiService.Spec.Service.Port)); errs != nil {
		allErrs = append(allErrs, field.Invalid(field.NewPath("spec", "service", "port"), apiService.Spec.Service.Port, "port is not valid: "+strings.Join(errs, ", ")))
	}
	if apiService.Spec.InsecureSkipTLSVerify && len(apiService.Spec.CABundle) > 0 {
		allErrs = append(allErrs, field.Invalid(field.NewPath("spec", "insecureSkipTLSVerify"), apiService.Spec.InsecureSkipTLSVerify, "may not be true if caBundle is present"))
	}

	return allErrs
}

// ValidateAPIServiceUpdate validates an update of APIService.
func ValidateAPIServiceUpdate(newAPIService *apiregistration.APIService, oldAPIService *apiregistration.APIService) field.ErrorList {
	allErrs := validation.ValidateObjectMetaUpdate(&newAPIService.ObjectMeta, &oldAPIService.ObjectMeta, field.NewPath("metadata"))
	allErrs = append(allErrs, ValidateAPIService(newAPIService)...)

	return allErrs
}

// ValidateAPIServiceStatus validates that the APIService status is one of 'True', 'False' or 'Unknown'.
func ValidateAPIServiceStatus(status *apiregistration.APIServiceStatus, fldPath *field.Path) field.ErrorList {
	allErrs := field.ErrorList{}

	for i, condition := range status.Conditions {
		if condition.Status != apiregistration.ConditionTrue &&
			condition.Status != apiregistration.ConditionFalse &&
			condition.Status != apiregistration.ConditionUnknown {
			allErrs = append(allErrs, field.NotSupported(fldPath.Child("conditions").Index(i).Child("status"), condition.Status, []string{
				string(apiregistration.ConditionTrue), string(apiregistration.ConditionFalse), string(apiregistration.ConditionUnknown)}))
		}
	}

	return allErrs
}

// ValidateAPIServiceStatusUpdate validates an update of the status field of APIService.
func ValidateAPIServiceStatusUpdate(newAPIService *apiregistration.APIService, oldAPIService *apiregistration.APIService) field.ErrorList {
	allErrs := validation.ValidateObjectMetaUpdate(&newAPIService.ObjectMeta, &oldAPIService.ObjectMeta, field.NewPath("metadata"))
	allErrs = append(allErrs, ValidateAPIServiceStatus(&newAPIService.Status, field.NewPath("status"))...)
	return allErrs
}
