/*
Copyright 2020 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 common

import (
	"encoding/json"

	"github.com/ghodss/yaml"
	mf "github.com/manifestival/manifestival"
	"go.uber.org/zap"
	corev1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
	"k8s.io/client-go/kubernetes/scheme"
	eventingconfig "knative.dev/eventing/pkg/apis/config"
	"knative.dev/eventing/pkg/apis/eventing"

	eventingv1alpha1 "knative.dev/operator/pkg/apis/operator/v1alpha1"
)

// DefaultBrokerConfigMapTransform updates the default broker configMap with the value defined in the spec
func DefaultBrokerConfigMapTransform(instance *eventingv1alpha1.KnativeEventing, log *zap.SugaredLogger) mf.Transformer {
	return func(u *unstructured.Unstructured) error {
		if u.GetKind() == "ConfigMap" && u.GetName() == eventingconfig.DefaultsConfigName {
			var configMap = &corev1.ConfigMap{}
			err := scheme.Scheme.Convert(u, configMap, nil)
			if err != nil {
				log.Error(err, "Error converting Unstructured to ConfigMap", "unstructured", u, "configMap", configMap)
				return err
			}

			defaults, err := eventingconfig.NewDefaultsConfigFromConfigMap(configMap)
			if err != nil {
				log.Error(err, "Error parsing default broker ConfigMap", "unstructured", u, "configMap", configMap)
				return err
			}

			defaultBrokerClass := instance.Spec.DefaultBrokerClass
			if defaultBrokerClass == "" {
				defaultBrokerClass = eventing.MTChannelBrokerClassValue
			}
			defaults.ClusterDefault.BrokerClass = defaultBrokerClass

			err = writeDefaultsToConfigMap(defaults, configMap, log)
			if err != nil {
				log.Error(err, "Error converting Broker defaults to default broker ConfigMap", "defaults", defaults, "configMap", configMap)
				return err
			}

			err = scheme.Scheme.Convert(configMap, u, nil)
			if err != nil {
				return err
			}
			// The zero-value timestamp defaulted by the conversion causes
			// superfluous updates
			u.SetCreationTimestamp(metav1.Time{})
			log.Debugw("Finished updating Broker defaults configMap", "name", u.GetName(), "unstructured", u.Object)
		}
		return nil
	}
}

func writeDefaultsToConfigMap(defaults *eventingconfig.Defaults, configMap *corev1.ConfigMap, log *zap.SugaredLogger) error {
	jsonBytes, err := json.Marshal(defaults)
	if err != nil {
		log.Error("Defaults could not be converted to JSON", "defaults", defaults)
		return err
	}

	yamlBytes, err := yaml.JSONToYAML(jsonBytes)
	if err != nil {
		log.Error("Defaults could not be converted to YAML", "defaults", defaults)
		return err
	}

	configMap.Data[eventingconfig.BrokerDefaultsKey] = string(yamlBytes)
	return nil
}
