/*
Copyright 2017 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 main

import (
	"errors"
	"flag"
	"fmt"
	"os"
	"path/filepath"
	"strings"

	"github.com/golang/glog"
	"github.com/kubernetes-incubator/external-storage/lib/controller"
	"k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/util/wait"
	"k8s.io/client-go/kubernetes"
	"k8s.io/client-go/rest"
)

const (
	provisionerNameKey = "PROVISIONER_NAME"
)

type nfsProvisioner struct {
	client kubernetes.Interface
	server string
	path   string
}

const (
	mountPath = "/persistentvolumes"
)

var _ controller.Provisioner = &nfsProvisioner{}

func (p *nfsProvisioner) Provision(options controller.VolumeOptions) (*v1.PersistentVolume, error) {
	if options.PVC.Spec.Selector != nil {
		return nil, fmt.Errorf("claim Selector is not supported")
	}
	glog.V(4).Infof("nfs provisioner: VolumeOptions %v", options)

	pvcNamespace := options.PVC.Namespace
	pvcName := options.PVC.Name

	pvName := strings.Join([]string{pvcNamespace, pvcName, options.PVName}, "-")

	fullPath := filepath.Join(mountPath, pvName)
	glog.V(4).Infof("creating path %s", fullPath)
	if err := os.MkdirAll(fullPath, 0777); err != nil {
		return nil, errors.New("unable to create directory to provision new pv: " + err.Error())
	}
	os.Chmod(fullPath, 0777)

	path := filepath.Join(p.path, pvName)

	pv := &v1.PersistentVolume{
		ObjectMeta: metav1.ObjectMeta{
			Name: options.PVName,
		},
		Spec: v1.PersistentVolumeSpec{
			PersistentVolumeReclaimPolicy: options.PersistentVolumeReclaimPolicy,
			AccessModes:                   options.PVC.Spec.AccessModes,
			MountOptions:                  options.MountOptions,
			Capacity: v1.ResourceList{
				v1.ResourceName(v1.ResourceStorage): options.PVC.Spec.Resources.Requests[v1.ResourceName(v1.ResourceStorage)],
			},
			PersistentVolumeSource: v1.PersistentVolumeSource{
				NFS: &v1.NFSVolumeSource{
					Server:   p.server,
					Path:     path,
					ReadOnly: false,
				},
			},
		},
	}
	return pv, nil
}

func (p *nfsProvisioner) Delete(volume *v1.PersistentVolume) error {
	path := volume.Spec.PersistentVolumeSource.NFS.Path
	pvName := filepath.Base(path)
	oldPath := filepath.Join(mountPath, pvName)
	archivePath := filepath.Join(mountPath, "archived-"+pvName)
	glog.V(4).Infof("archiving path %s to %s", oldPath, archivePath)
	return os.Rename(oldPath, archivePath)
}

func main() {
	flag.Parse()
	flag.Set("logtostderr", "true")

	server := os.Getenv("NFS_SERVER")
	if server == "" {
		glog.Fatal("NFS_SERVER not set")
	}
	path := os.Getenv("NFS_PATH")
	if path == "" {
		glog.Fatal("NFS_PATH not set")
	}
	provisionerName := os.Getenv(provisionerNameKey)
	if provisionerName == "" {
		glog.Fatalf("environment variable %s is not set! Please set it.", provisionerNameKey)
	}

	// Create an InClusterConfig and use it to create a client for the controller
	// to use to communicate with Kubernetes
	config, err := rest.InClusterConfig()
	if err != nil {
		glog.Fatalf("Failed to create config: %v", err)
	}
	clientset, err := kubernetes.NewForConfig(config)
	if err != nil {
		glog.Fatalf("Failed to create client: %v", err)
	}

	// The controller needs to know what the server version is because out-of-tree
	// provisioners aren't officially supported until 1.5
	serverVersion, err := clientset.Discovery().ServerVersion()
	if err != nil {
		glog.Fatalf("Error getting server version: %v", err)
	}

	clientNFSProvisioner := &nfsProvisioner{
		server: server,
		path:   path,
	}
	// Start the provision controller which will dynamically provision efs NFS
	// PVs
	pc := controller.NewProvisionController(clientset, provisionerName, clientNFSProvisioner, serverVersion.GitVersion)
	pc.Run(wait.NeverStop)
}