/*
Copyright 2019 The Knative Authors

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 v1

import (
	"context"
	"strings"

	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"knative.dev/pkg/apis"
	"knative.dev/serving/pkg/apis/serving"
)

// Validate makes sure that Configuration is properly configured.
func (c *Configuration) Validate(ctx context.Context) (errs *apis.FieldError) {
	// If we are in a status sub resource update, the metadata and spec cannot change.
	// So, to avoid rejecting controller status updates due to validations that may
	// have changed (i.e. due to config-defaults changes), we elide the metadata and
	// spec validation.
	if !apis.IsInStatusUpdate(ctx) {
		errs = errs.Also(serving.ValidateObjectMetadata(ctx, c.GetObjectMeta()))
		errs = errs.Also(c.validateLabels().ViaField("labels"))
		errs = errs.Also(serving.ValidateHasNoAutoscalingAnnotation(c.GetAnnotations()).ViaField("annotations"))
		errs = errs.ViaField("metadata")

		ctx = apis.WithinParent(ctx, c.ObjectMeta)
		errs = errs.Also(c.Spec.Validate(apis.WithinSpec(ctx)).ViaField("spec"))
	}

	errs = errs.Also(c.Status.Validate(apis.WithinStatus(ctx)).ViaField("status"))

	if apis.IsInUpdate(ctx) {
		original := apis.GetBaseline(ctx).(*Configuration)
		// Don't validate annotations(creator and lastModifier) when configuration owned by service
		// validate only when configuration created independently.
		if c.OwnerReferences == nil {
			errs = errs.Also(apis.ValidateCreatorAndModifier(original.Spec, c.Spec, original.GetAnnotations(),
				c.GetAnnotations(), serving.GroupName).ViaField("metadata.annotations"))
		}
		err := c.Spec.Template.VerifyNameChange(ctx, original.Spec.Template)
		errs = errs.Also(err.ViaField("spec.template"))
	}

	return errs
}

// Validate implements apis.Validatable
func (cs *ConfigurationSpec) Validate(ctx context.Context) *apis.FieldError {
	return cs.Template.Validate(ctx).ViaField("template")
}

// Validate implements apis.Validatable
func (cs *ConfigurationStatus) Validate(ctx context.Context) *apis.FieldError {
	return cs.ConfigurationStatusFields.Validate(ctx)
}

// Validate implements apis.Validatable
func (csf *ConfigurationStatusFields) Validate(ctx context.Context) *apis.FieldError {
	return nil
}

// validateLabels function validates configuration labels
func (c *Configuration) validateLabels() (errs *apis.FieldError) {
	for key, val := range c.GetLabels() {
		switch key {
		case serving.RouteLabelKey, serving.VisibilityLabelKeyObsolete:
			// Known valid labels.
		case serving.ServiceLabelKey:
			errs = errs.Also(verifyLabelOwnerRef(val, serving.ServiceLabelKey, "Service", c.GetOwnerReferences()))
		default:
			if strings.HasPrefix(key, serving.GroupNamePrefix) {
				errs = errs.Also(apis.ErrInvalidKeyName(key, apis.CurrentField))
			}
		}
	}
	return
}

// verifyLabelOwnerRef function verifies the owner references of resource with label key has val value.
func verifyLabelOwnerRef(val, label, resource string, ownerRefs []metav1.OwnerReference) (errs *apis.FieldError) {
	for _, ref := range ownerRefs {
		if ref.Kind == resource && val == ref.Name {
			return
		}
	}
	return errs.Also(apis.ErrMissingField(label))
}
