// Copyright (c) 2018 SAP SE or an SAP affiliate company. All rights reserved. This file is licensed under the Apache Software License, v. 2 except as noted otherwise in the LICENSE file
//
// 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 (
	apisgcp "github.com/gardener/gardener-extension-provider-gcp/pkg/apis/gcp"
	"k8s.io/apimachinery/pkg/util/sets"

	apivalidation "k8s.io/apimachinery/pkg/api/validation"
	"k8s.io/apimachinery/pkg/util/validation/field"
)

// ValidateControlPlaneConfig validates a ControlPlaneConfig object.
func ValidateControlPlaneConfig(controlPlaneConfig *apisgcp.ControlPlaneConfig, allowedZones, workerZones sets.String, fldPath *field.Path) field.ErrorList {
	allErrs := field.ErrorList{}

	if len(controlPlaneConfig.Zone) == 0 {
		allErrs = append(allErrs, field.Required(fldPath.Child("zone"), "must provide the name of a zone in this region"))
	} else if ok, validZones := validateZoneConstraints(allowedZones, controlPlaneConfig.Zone); !ok {
		allErrs = append(allErrs, field.NotSupported(fldPath.Child("zone"), controlPlaneConfig.Zone, validZones))
	}

	if !workerZones.Has(controlPlaneConfig.Zone) {
		allErrs = append(allErrs, field.Invalid(fldPath.Child("zone"), controlPlaneConfig.Zone, "must be part of at least one worker zone"))
	}
	return allErrs
}

// ValidateControlPlaneConfigUpdate validates a ControlPlaneConfig object.
func ValidateControlPlaneConfigUpdate(oldConfig, newConfig *apisgcp.ControlPlaneConfig, fldPath *field.Path) field.ErrorList {
	allErrs := field.ErrorList{}

	allErrs = append(allErrs, apivalidation.ValidateImmutableField(newConfig.Zone, oldConfig.Zone, fldPath.Child("zone"))...)

	return allErrs
}

func validateZoneConstraints(allowedZones sets.String, zone string) (bool, []string) {
	if allowedZones.Has(zone) {
		return true, nil
	}

	return false, allowedZones.UnsortedList()
}