/*
 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 services

import (
	"bytes"
	"context"
	"fmt"
	"strings"

	"html/template"
	airshipv1 "sipcluster/pkg/api/v1"
	bmh "sipcluster/pkg/bmh"

	"github.com/go-logr/logr"
	"k8s.io/apimachinery/pkg/types"

	appsv1 "k8s.io/api/apps/v1"
	corev1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"sigs.k8s.io/controller-runtime/pkg/client"
)

const (
	// ConfigSecretName name of the haproxy config secret name/volume/mount
	/* #nosec */
	ConfigSecretName = "haproxy-config"
	// DefaultBalancerImage is the image that will be used as load balancer
	DefaultBalancerImage    = "haproxy:2.3.2"
	LoadBalancerServiceName = "loadbalancer"
)

func (lb loadBalancer) Deploy() error {
	if lb.config.Image == "" {
		lb.config.Image = DefaultBalancerImage
	}

	instance := LoadBalancerServiceName + "-" + strings.ToLower(string(lb.bmhRole)) + "-" + lb.sipName.Name
	labels := map[string]string{
		// See https://kubernetes.io/docs/concepts/overview/working-with-objects/common-labels/#labels
		"app.kubernetes.io/part-of":   "sip",
		"app.kubernetes.io/component": LoadBalancerServiceName,
		"app.kubernetes.io/name":      "haproxy",
		"app.kubernetes.io/instance":  instance,
	}

	deployment, secret, err := lb.generateDeploymentAndSecret(instance, labels)
	if err != nil {
		return err
	}

	lb.logger.Info("Applying loadbalancer secret", "secret", secret.GetNamespace()+"/"+secret.GetName())
	err = applyRuntimeObject(client.ObjectKey{Name: secret.GetName(), Namespace: secret.GetNamespace()}, secret, lb.client)
	if err != nil {
		return err
	}

	// TODO: Validate Deployment becomes ready.
	lb.logger.Info("Applying loadbalancer deployment", "deployment", deployment.GetNamespace()+"/"+deployment.GetName())
	err = applyRuntimeObject(client.ObjectKey{Name: deployment.GetName(), Namespace: deployment.GetNamespace()},
		deployment, lb.client)
	if err != nil {
		return err
	}

	// TODO: Validate Service becomes ready.
	lbService := lb.generateService(instance, labels)
	lb.logger.Info("Applying loadbalancer service", "service", lbService.GetNamespace()+"/"+lbService.GetName())
	err = applyRuntimeObject(client.ObjectKey{Name: lbService.GetName(), Namespace: lbService.GetNamespace()},
		lbService, lb.client)
	if err != nil {
		return err
	}
	return nil
}

func (lb loadBalancer) generateDeploymentAndSecret(instance string, labels map[string]string) (*appsv1.Deployment,
	*corev1.Secret, error) {
	secret, err := lb.generateSecret(instance)
	if err != nil {
		return nil, nil, err
	}

	deployment := &appsv1.Deployment{
		ObjectMeta: metav1.ObjectMeta{
			Name:      instance,
			Namespace: lb.sipName.Namespace,
			Labels:    labels,
		},
		Spec: appsv1.DeploymentSpec{
			Replicas: int32Ptr(1),
			Selector: &metav1.LabelSelector{
				MatchLabels: labels,
			},
			Template: corev1.PodTemplateSpec{
				ObjectMeta: metav1.ObjectMeta{
					Labels: labels,
				},
				Spec: corev1.PodSpec{
					Containers: []corev1.Container{
						{
							Name:            LoadBalancerServiceName,
							Image:           lb.config.Image,
							ImagePullPolicy: corev1.PullIfNotPresent,
							Ports:           lb.getContainerPorts(),
							VolumeMounts: []corev1.VolumeMount{
								{
									Name:      ConfigSecretName,
									MountPath: "/usr/local/etc/haproxy",
								},
							},
						},
					},
					NodeSelector: map[string]string{
						"node-role.kubernetes.io/master": "",
					},
					Tolerations: []corev1.Toleration{
						{
							Key:    "node-role.kubernetes.io/master",
							Effect: "NoSchedule",
						},
					},
					Volumes: []corev1.Volume{
						{
							Name: ConfigSecretName,
							VolumeSource: corev1.VolumeSource{
								Secret: &corev1.SecretVolumeSource{
									SecretName: secret.GetName(),
								},
							},
						},
					},
				},
			},
		},
	}

	return deployment, secret, nil
}

func (lb loadBalancer) getContainerPorts() []corev1.ContainerPort {
	containerPorts := []corev1.ContainerPort{}
	for _, servicePort := range lb.servicePorts {
		containerPorts = append(containerPorts, corev1.ContainerPort{
			Name:          servicePort.Name,
			ContainerPort: servicePort.Port,
		})
	}
	return containerPorts
}

func (lb loadBalancer) generateSecret(instance string) (*corev1.Secret, error) {
	p := proxy{
		ContainerPorts: lb.getContainerPorts(),
		Servers:        make([]server, 0),
	}
	for _, machine := range lb.machines.Machines {
		if machine.BMHRole == lb.bmhRole {
			name := machine.BMH.Name
			namespace := machine.BMH.Namespace
			ip, exists := machine.Data.IPOnInterface[lb.config.NodeInterface]
			if !exists {
				lb.logger.Info("Machine does not have backend interface to be forwarded to",
					"interface", lb.config.NodeInterface,
					"machine", namespace+"/"+name,
				)
				continue
			}
			p.Servers = append(p.Servers, server{IP: ip, Name: machine.BMH.Name})
		}
	}
	secretData, err := lb.generateTemplate(p)
	if err != nil {
		return nil, err
	}
	return &corev1.Secret{
		ObjectMeta: metav1.ObjectMeta{
			Name:      instance,
			Namespace: lb.sipName.Namespace,
		},
		Type: corev1.SecretTypeOpaque,
		Data: map[string][]byte{
			"haproxy.cfg": secretData,
		},
	}, nil
}

func (lb loadBalancer) generateService(instance string, labels map[string]string) *corev1.Service {
	return &corev1.Service{
		ObjectMeta: metav1.ObjectMeta{
			Name:      instance,
			Namespace: lb.sipName.Namespace,
		},
		Spec: corev1.ServiceSpec{
			Ports:    lb.servicePorts,
			Selector: labels,
			Type:     corev1.ServiceTypeNodePort,
		},
	}
}

type proxy struct {
	ContainerPorts []corev1.ContainerPort
	Servers        []server
}

type server struct {
	IP   string
	Name string
}

type loadBalancer struct {
	client       client.Client
	sipName      types.NamespacedName
	logger       logr.Logger
	config       airshipv1.SIPClusterService
	machines     *bmh.MachineList
	bmhRole      airshipv1.BMHRole
	template     string
	servicePorts []corev1.ServicePort
}

type loadBalancerControlPlane struct {
	loadBalancer
	config airshipv1.LoadBalancerServiceControlPlane
}

type loadBalancerWorker struct {
	loadBalancer
	config airshipv1.LoadBalancerServiceWorker
}

func newLBControlPlane(name, namespace string,
	logger logr.Logger,
	config airshipv1.LoadBalancerServiceControlPlane,
	machines *bmh.MachineList,
	mgrClient client.Client) loadBalancerControlPlane {
	servicePorts := []corev1.ServicePort{
		{
			Name:     "http",
			Port:     6443,
			NodePort: int32(config.NodePort),
		},
	}
	//Get template string from the secret
	templateControlPlane := ""
	cm := &corev1.ConfigMap{}
	err := mgrClient.Get(context.Background(), client.ObjectKey{
		Name:      "loadbalancercontrolplane",
		Namespace: namespace}, cm)
	if err != nil {
		logger.Error(err, "unable to retrieve template info from secret.")
	}
	templateControlPlane = cm.Data["loadBalancerControlPlane.cfg"]

	return loadBalancerControlPlane{loadBalancer{
		sipName: types.NamespacedName{
			Name:      name,
			Namespace: namespace,
		},
		logger:       logger,
		config:       config.SIPClusterService,
		machines:     machines,
		client:       mgrClient,
		bmhRole:      airshipv1.RoleControlPlane,
		template:     templateControlPlane,
		servicePorts: servicePorts,
	},
		config,
	}
}

func newLBWorker(name, namespace string,
	logger logr.Logger,
	config airshipv1.LoadBalancerServiceWorker,
	machines *bmh.MachineList,
	mgrClient client.Client) loadBalancerWorker {
	servicePorts := []corev1.ServicePort{}
	for port := config.NodePortRange.Start; port <= config.NodePortRange.End; port++ {
		servicePorts = append(servicePorts, corev1.ServicePort{
			Name:     fmt.Sprintf("port-%d", port),
			Port:     int32(port),
			NodePort: int32(port),
		})
	}

	//Get Template as a secret
	templateWorker := ""
	cm := &corev1.ConfigMap{}
	err := mgrClient.Get(context.Background(), client.ObjectKey{
		Name:      "loadbalancerworker",
		Namespace: namespace}, cm)
	if err != nil {
		logger.Error(err, "unable to retrieve template info from secret.")
	}
	templateWorker = cm.Data["loadBalancerWorker.cfg"]

	return loadBalancerWorker{loadBalancer{
		sipName: types.NamespacedName{
			Name:      name,
			Namespace: namespace,
		},
		logger:       logger,
		config:       config.SIPClusterService,
		machines:     machines,
		client:       mgrClient,
		bmhRole:      airshipv1.RoleWorker,
		template:     templateWorker,
		servicePorts: servicePorts,
	},
		config,
	}
}

func (lb loadBalancer) Finalize() error {
	// implete to delete loadbalancer
	return nil
}

func (lb loadBalancer) generateTemplate(p proxy) ([]byte, error) {
	tmpl, err := template.New("haproxy-config").Parse(lb.template)
	if err != nil {
		return nil, err
	}

	w := bytes.NewBuffer([]byte{})
	if err := tmpl.Execute(w, p); err != nil {
		return nil, err
	}

	rendered := w.Bytes()
	return rendered, nil
}