/*
Copyright 2018 The Kubernetes 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 webhook

import (
	"encoding/json"

	v1 "k8s.io/api/admission/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/klog"
)

const (
	customResourcePatch1 string = `[
         { "op": "add", "path": "/data/mutation-stage-1", "value": "yes" }
     ]`
	customResourcePatch2 string = `[
         { "op": "add", "path": "/data/mutation-stage-2", "value": "yes" }
     ]`
)

func mutateCustomResource(ar v1.AdmissionReview) *v1.AdmissionResponse {
	klog.V(2).Info("mutating custom resource")
	cr := struct {
		metav1.ObjectMeta
		Data map[string]string
	}{}

	raw := ar.Request.Object.Raw
	err := json.Unmarshal(raw, &cr)
	if err != nil {
		klog.Error(err)
		return toV1AdmissionResponse(err)
	}

	reviewResponse := v1.AdmissionResponse{}
	reviewResponse.Allowed = true

	if cr.Data["mutation-start"] == "yes" {
		reviewResponse.Patch = []byte(customResourcePatch1)
	}
	if cr.Data["mutation-stage-1"] == "yes" {
		reviewResponse.Patch = []byte(customResourcePatch2)
	}
	if len(reviewResponse.Patch) != 0 {
		pt := v1.PatchTypeJSONPatch
		reviewResponse.PatchType = &pt
	}
	return &reviewResponse
}

func admitCustomResource(ar v1.AdmissionReview) *v1.AdmissionResponse {
	klog.V(2).Info("admitting custom resource")
	cr := struct {
		metav1.ObjectMeta
		Data map[string]string
	}{}

	var raw []byte
	if ar.Request.Operation == v1.Delete {
		raw = ar.Request.OldObject.Raw
	} else {
		raw = ar.Request.Object.Raw
	}
	err := json.Unmarshal(raw, &cr)
	if err != nil {
		klog.Error(err)
		return toV1AdmissionResponse(err)
	}

	reviewResponse := v1.AdmissionResponse{}
	reviewResponse.Allowed = true
	for k, v := range cr.Data {
		if k == "webhook-e2e-test" && v == "webhook-disallow" &&
			(ar.Request.Operation == v1.Create || ar.Request.Operation == v1.Update) {
			reviewResponse.Allowed = false
			reviewResponse.Result = &metav1.Status{
				Reason: "the custom resource contains unwanted data",
			}
		}
		if k == "webhook-e2e-test" && v == "webhook-nondeletable" && ar.Request.Operation == v1.Delete {
			reviewResponse.Allowed = false
			reviewResponse.Result = &metav1.Status{
				Reason: "the custom resource cannot be deleted because it contains unwanted key and value",
			}
		}
	}
	return &reviewResponse
}
