/*
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

    https://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 reconciler

import (
	"context"

	"go.uber.org/zap"
	corev1 "k8s.io/api/core/v1"
	apiextensionsclientset "k8s.io/apiextensions-apiserver/pkg/client/clientset/clientset"
	"k8s.io/apimachinery/pkg/watch"
	"k8s.io/client-go/dynamic"
	"k8s.io/client-go/kubernetes"
	"k8s.io/client-go/kubernetes/scheme"
	typedcorev1 "k8s.io/client-go/kubernetes/typed/core/v1"
	"k8s.io/client-go/tools/record"
	clientset "knative.dev/eventing/pkg/client/clientset/versioned"
	eventingScheme "knative.dev/eventing/pkg/client/clientset/versioned/scheme"
	legacyclientset "knative.dev/eventing/pkg/legacyclient/clientset/versioned"
	legacyScheme "knative.dev/eventing/pkg/legacyclient/clientset/versioned/scheme"
	"knative.dev/pkg/configmap"
	"knative.dev/pkg/controller"
	"knative.dev/pkg/logging"
	"knative.dev/pkg/logging/logkey"

	eventingclient "knative.dev/eventing/pkg/client/injection/client"
	legacyclient "knative.dev/eventing/pkg/legacyclient/injection/client"
	kubeclient "knative.dev/pkg/client/injection/kube/client"
	"knative.dev/pkg/injection/clients/dynamicclient"
)

// Base implements the core controller logic, given a Reconciler.
type Base struct {
	// KubeClientSet allows us to talk to the k8s for core APIs
	KubeClientSet kubernetes.Interface

	// EventingClientSet allows us to configure Eventing objects
	EventingClientSet clientset.Interface

	// LegacyClientSet allows us to configure Legacy Eventing objects
	LegacyClientSet legacyclientset.Interface

	// ApiExtensionsClientSet allows us to configure k8s API extension objects.
	ApiExtensionsClientSet apiextensionsclientset.Interface

	// DynamicClientSet allows us to configure pluggable Build objects
	DynamicClientSet dynamic.Interface

	// ConfigMapWatcher allows us to watch for ConfigMap changes.
	ConfigMapWatcher configmap.Watcher

	// Recorder is an event recorder for recording Event resources to the
	// Kubernetes API.
	Recorder record.EventRecorder

	// StatsReporter reports reconciler's metrics.
	StatsReporter StatsReporter

	// Sugared logger is easier to use but is not as performant as the
	// raw logger. In performance critical paths, call logger.Desugar()
	// and use the returned raw logger instead. In addition to the
	// performance benefits, raw logger also preserves type-safety at
	// the expense of slightly greater verbosity.
	Logger *zap.SugaredLogger
}

// NewBase instantiates a new instance of Base implementing
// the common & boilerplate code between our reconcilers.
func NewBase(ctx context.Context, controllerAgentName string, cmw configmap.Watcher) *Base {
	// Enrich the logs with controller name
	logger := logging.FromContext(ctx).
		Named(controllerAgentName).
		With(zap.String(logkey.ControllerType, controllerAgentName))

	kubeClient := kubeclient.Get(ctx)

	recorder := controller.GetEventRecorder(ctx)
	if recorder == nil {
		// Create event broadcaster
		logger.Debug("Creating event broadcaster")
		eventBroadcaster := record.NewBroadcaster()
		watches := []watch.Interface{
			eventBroadcaster.StartLogging(logger.Named("event-broadcaster").Infof),
			eventBroadcaster.StartRecordingToSink(
				&typedcorev1.EventSinkImpl{Interface: kubeClient.CoreV1().Events("")}),
		}
		recorder = eventBroadcaster.NewRecorder(
			scheme.Scheme, corev1.EventSource{Component: controllerAgentName})
		go func() {
			<-ctx.Done()
			for _, w := range watches {
				w.Stop()
			}
		}()
	}

	statsReporter := GetStatsReporter(ctx)
	if statsReporter == nil {
		logger.Debug("Creating stats reporter")
		var err error
		statsReporter, err = NewStatsReporter(controllerAgentName)
		if err != nil {
			logger.Fatal(err)
		}
	}

	base := &Base{
		KubeClientSet:     kubeClient,
		EventingClientSet: eventingclient.Get(ctx),
		LegacyClientSet:   legacyclient.Get(ctx),
		DynamicClientSet:  dynamicclient.Get(ctx),
		ConfigMapWatcher:  cmw,
		Recorder:          recorder,
		StatsReporter:     statsReporter,
		Logger:            logger,
	}

	return base
}

func init() {
	// Add eventing types to the default Kubernetes Scheme so Events can be
	// logged for eventing types.
	eventingScheme.AddToScheme(scheme.Scheme)
	legacyScheme.AddToScheme(scheme.Scheme)
}
