/*
Copyright 2022.

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 controllers

import (
	"context"
	"fmt"
	"strings"

	v1 "github.com/kakao/bluegreen/api/v1"
	appsv1 "k8s.io/api/apps/v1"
	corev1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/runtime"
	ctrl "sigs.k8s.io/controller-runtime"
	"sigs.k8s.io/controller-runtime/pkg/client"
	"sigs.k8s.io/controller-runtime/pkg/log"
)

// BlueGreenReconciler reconciles a BlueGreen object
type BlueGreenReconciler struct {
	client.Client
	Scheme *runtime.Scheme
}

//+kubebuilder:rbac:groups=app.demo.kakao.com,resources=bluegreens,verbs=get;list;watch;create;update;patch;delete
//+kubebuilder:rbac:groups=app.demo.kakao.com,resources=bluegreens/status,verbs=get;update;patch
//+kubebuilder:rbac:groups=app.demo.kakao.com,resources=bluegreens/finalizers,verbs=update

//+kubebuilder:rbac:groups=apps,resources=deployments,verbs=get;watch;create;update;patch
//+kubebuilder:rbac:groups=,resources=services,verbs=get;create;update;patch

func (r *BlueGreenReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
	log := log.FromContext(ctx)
	log.Info("event", "name", req.Name, "namespace", req.Namespace)

	bluegreen := new(v1.BlueGreen)
	if err := r.Client.Get(ctx, req.NamespacedName, bluegreen); err != nil {
		return ctrl.Result{}, client.IgnoreNotFound(err)
	}

	// Create or Update Service
	svc := &corev1.Service{ObjectMeta: metav1.ObjectMeta{Namespace: req.Namespace, Name: req.Name}}
	if _, err := ctrl.CreateOrUpdate(ctx, r.Client, svc, func() error {
		if err := ctrl.SetControllerReference(bluegreen, svc, r.Scheme); err != nil {
			return err
		}
		svc.Spec.Ports = []corev1.ServicePort{
			{Name: "http", Protocol: corev1.ProtocolTCP, Port: 80},
		}
		svc.Spec.Selector = map[string]string{
			"app.kubernetes.io/managed-by": "app.demo.kakao.com",
			"app.kubernetes.io/name":       req.Name,
			"app.kubernetes.io/phase":      string(bluegreen.Spec.RouteTo),
		}
		return nil
	}); err != nil {
		return ctrl.Result{}, err
	}

	// Create or Update BlueDeployment
	for _, bg := range []v1.BlueOrGreen{v1.Blue, v1.Green} {
		spec := bluegreen.Spec.BlueSpec
		if bg == v1.Green {
			spec = bluegreen.Spec.GreenSpec
		}
		if spec == nil {
			continue
		}
		deploy := &appsv1.Deployment{ObjectMeta: metav1.ObjectMeta{Namespace: req.Namespace, Name: deploymentName(req.Name, bg)}}
		if _, err := ctrl.CreateOrUpdate(ctx, r.Client, deploy, func() error {
			if err := ctrl.SetControllerReference(bluegreen, deploy, r.Scheme); err != nil {
				return err
			}
			label := map[string]string{
				"app.kubernetes.io/managed-by": "app.demo.kakao.com",
				"app.kubernetes.io/name":       req.Name,
				"app.kubernetes.io/phase":      string(bg),
			}
			deploy.Spec.Selector = &metav1.LabelSelector{MatchLabels: label}
			deploy.Spec.Template = corev1.PodTemplateSpec{
				ObjectMeta: metav1.ObjectMeta{Labels: label},
				Spec:       *spec,
			}
			return nil
		}); err != nil {
			return ctrl.Result{}, err
		}
	}

	bluegreen.Status = v1.BlueGreenStatus{
		RouteTo: &bluegreen.Spec.RouteTo,
	}
	return ctrl.Result{}, r.Client.Status().Update(ctx, bluegreen)
}

// SetupWithManager sets up the controller with the Manager.
func (r *BlueGreenReconciler) SetupWithManager(mgr ctrl.Manager) error {
	return ctrl.NewControllerManagedBy(mgr).
		For(&v1.BlueGreen{}).
		Complete(r)
}

func deploymentName(name string, bg v1.BlueOrGreen) string {
	return fmt.Sprintf("%s-%s", name, strings.ToLower(string(bg)))
}