/*
Copyright 2016 The Kubernetes Authors All rights reserved.

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 vsphere

import (
	"bytes"
	"errors"
	"fmt"
	"io"
	"net/url"
	"os/exec"
	"strings"

	"github.com/vmware/govmomi"
	"github.com/vmware/govmomi/find"
	"github.com/vmware/govmomi/object"
	"github.com/vmware/govmomi/property"
	"github.com/vmware/govmomi/vim25/mo"
	"github.com/vmware/govmomi/vim25/types"
	"golang.org/x/net/context"
	"gopkg.in/gcfg.v1"

	"github.com/golang/glog"
	"k8s.io/kubernetes/pkg/api"
	"k8s.io/kubernetes/pkg/cloudprovider"
)

const ProviderName = "vsphere"
const ActivePowerState = "poweredOn"

// VSphere is an implementation of cloud provider Interface for VSphere.
type VSphere struct {
	cfg *VSphereConfig
	// InstanceID of the server where this VSphere object is instantiated.
	localInstanceID string
}

type VSphereConfig struct {
	Global struct {
		User         string `gcfg:"user"`
		Password     string `gcfg:"password"`
		VCenterIP    string `gcfg:"server"`
		VCenterPort  string `gcfg:"port"`
		InsecureFlag bool   `gcfg:"insecure-flag"`
		Datacenter   string `gcfg:"datacenter"`
		Datastore    string `gcfg:"datastore"`
	}

	Network struct {
		PublicNetwork string `gcfg:"public-network"`
	}
}

func readConfig(config io.Reader) (VSphereConfig, error) {
	if config == nil {
		err := fmt.Errorf("no vSphere cloud provider config file given")
		return VSphereConfig{}, err
	}

	var cfg VSphereConfig
	err := gcfg.ReadInto(&cfg, config)
	return cfg, err
}

func init() {
	cloudprovider.RegisterCloudProvider(ProviderName, func(config io.Reader) (cloudprovider.Interface, error) {
		cfg, err := readConfig(config)
		if err != nil {
			return nil, err
		}
		return newVSphere(cfg)
	})
}

func readInstanceID(cfg *VSphereConfig) (string, error) {
	cmd := exec.Command("bash", "-c", `dmidecode -t 1 | grep UUID | tr -d ' ' | cut -f 2 -d ':'`)
	var out bytes.Buffer
	cmd.Stdout = &out
	err := cmd.Run()
	if err != nil {
		return "", err
	}

	// Create context
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	// Create vSphere client
	c, err := vsphereLogin(cfg, ctx)
	if err != nil {
		return "", err
	}
	defer c.Logout(ctx)

	// Create a new finder
	f := find.NewFinder(c.Client, true)

	// Fetch and set data center
	dc, err := f.Datacenter(ctx, cfg.Global.Datacenter)
	if err != nil {
		return "", err
	}
	f.SetDatacenter(dc)

	s := object.NewSearchIndex(c.Client)

	svm, err := s.FindByUuid(ctx, dc, strings.ToLower(strings.TrimSpace(out.String())), true, nil)
	var vm mo.VirtualMachine
	err = s.Properties(ctx, svm.Reference(), []string{"name"}, &vm)
	if err != nil {
		return "", err
	}
	return vm.Name, nil
}

func newVSphere(cfg VSphereConfig) (*VSphere, error) {
	id, err := readInstanceID(&cfg)
	if err != nil {
		return nil, err
	}

	vs := VSphere{
		cfg:             &cfg,
		localInstanceID: id,
	}
	return &vs, nil
}

func vsphereLogin(cfg *VSphereConfig, ctx context.Context) (*govmomi.Client, error) {

	// Parse URL from string
	u, err := url.Parse(fmt.Sprintf("https://%s:%s/sdk", cfg.Global.VCenterIP, cfg.Global.VCenterPort))
	if err != nil {
		return nil, err
	}
	// set username and password for the URL
	u.User = url.UserPassword(cfg.Global.User, cfg.Global.Password)

	// Connect and log in to ESX or vCenter
	c, err := govmomi.NewClient(ctx, u, cfg.Global.InsecureFlag)
	if err != nil {
		return nil, err
	}

	return c, nil
}

func getVirtualMachineByName(cfg *VSphereConfig, ctx context.Context, c *govmomi.Client, name string) (*object.VirtualMachine, error) {
	// Create a new finder
	f := find.NewFinder(c.Client, true)

	// Fetch and set data center
	dc, err := f.Datacenter(ctx, cfg.Global.Datacenter)
	if err != nil {
		return nil, err
	}
	f.SetDatacenter(dc)

	// Retrieve vm by name
	//TODO: also look for vm inside subfolders
	vm, err := f.VirtualMachine(ctx, name)
	if err != nil {
		return nil, err
	}

	return vm, nil
}

func getVirtualMachineManagedObjectReference(ctx context.Context, c *govmomi.Client, vm *object.VirtualMachine, field string, dst interface{}) error {
	collector := property.DefaultCollector(c.Client)

	// Retrieve required field from VM object
	err := collector.RetrieveOne(ctx, vm.Reference(), []string{field}, dst)
	if err != nil {
		return err
	}
	return nil
}

func getInstances(cfg *VSphereConfig, ctx context.Context, c *govmomi.Client, filter string) ([]string, error) {
	f := find.NewFinder(c.Client, true)
	dc, err := f.Datacenter(ctx, cfg.Global.Datacenter)
	if err != nil {
		return nil, err
	}

	f.SetDatacenter(dc)

	//TODO: get all vms inside subfolders
	vms, err := f.VirtualMachineList(ctx, filter)
	if err != nil {
		return nil, err
	}

	var vmRef []types.ManagedObjectReference
	for _, vm := range vms {
		vmRef = append(vmRef, vm.Reference())
	}

	pc := property.DefaultCollector(c.Client)

	var vmt []mo.VirtualMachine
	err = pc.Retrieve(ctx, vmRef, []string{"name", "summary"}, &vmt)
	if err != nil {
		return nil, err
	}

	var vmList []string
	for _, vm := range vmt {
		if vm.Summary.Runtime.PowerState == ActivePowerState {
			vmList = append(vmList, vm.Name)
		} else if vm.Summary.Config.Template == false {
			glog.Warningf("VM %s, is not in %s state", vm.Name, ActivePowerState)
		}
	}
	return vmList, nil
}

type Instances struct {
	cfg             *VSphereConfig
	localInstanceID string
}

// Instances returns an implementation of Instances for vSphere.
func (vs *VSphere) Instances() (cloudprovider.Instances, bool) {
	return &Instances{vs.cfg, vs.localInstanceID}, true
}

// List is an implementation of Instances.List.
func (i *Instances) List(filter string) ([]string, error) {
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()
	c, err := vsphereLogin(i.cfg, ctx)
	if err != nil {
		return nil, err
	}
	defer c.Logout(ctx)

	vmList, err := getInstances(i.cfg, ctx, c, filter)
	if err != nil {
		return nil, err
	}

	glog.V(3).Infof("Found %s instances matching %s: %s",
		len(vmList), filter, vmList)

	return vmList, nil
}

// NodeAddresses is an implementation of Instances.NodeAddresses.
func (i *Instances) NodeAddresses(name string) ([]api.NodeAddress, error) {
	addrs := []api.NodeAddress{}

	// Create context
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	// Create vSphere client
	c, err := vsphereLogin(i.cfg, ctx)
	if err != nil {
		return nil, err
	}
	defer c.Logout(ctx)

	vm, err := getVirtualMachineByName(i.cfg, ctx, c, name)
	if err != nil {
		return nil, err
	}

	var mvm mo.VirtualMachine
	err = getVirtualMachineManagedObjectReference(ctx, c, vm, "guest.net", &mvm)
	if err != nil {
		return nil, err
	}

	// retrieve VM's ip(s)
	for _, v := range mvm.Guest.Net {
		var addressType api.NodeAddressType
		if i.cfg.Network.PublicNetwork == v.Network {
			addressType = api.NodeExternalIP
		} else {
			addressType = api.NodeInternalIP
		}
		for _, ip := range v.IpAddress {
			api.AddToNodeAddresses(&addrs,
				api.NodeAddress{
					Type:    addressType,
					Address: ip,
				},
			)
		}
	}
	return addrs, nil
}

func (i *Instances) AddSSHKeyToAllInstances(user string, keyData []byte) error {
	return errors.New("unimplemented")
}

func (i *Instances) CurrentNodeName(hostname string) (string, error) {
	return i.localInstanceID, nil
}

// ExternalID returns the cloud provider ID of the specified instance (deprecated).
func (i *Instances) ExternalID(name string) (string, error) {
	// Create context
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	// Create vSphere client
	c, err := vsphereLogin(i.cfg, ctx)
	if err != nil {
		return "", err
	}
	defer c.Logout(ctx)

	vm, err := getVirtualMachineByName(i.cfg, ctx, c, name)
	if err != nil {
		return "", err
	}

	var mvm mo.VirtualMachine
	err = getVirtualMachineManagedObjectReference(ctx, c, vm, "summary", &mvm)
	if err != nil {
		return "", err
	}

	if mvm.Summary.Runtime.PowerState == ActivePowerState {
		return vm.InventoryPath, nil
	}

	if mvm.Summary.Config.Template == false {
		glog.Warningf("VM %s, is not in %s state", name, ActivePowerState)
	} else {
		glog.Warningf("VM %s, is a template", name)
	}

	return "", cloudprovider.InstanceNotFound
}

// InstanceID returns the cloud provider ID of the specified instance.
func (i *Instances) InstanceID(name string) (string, error) {
	// Create context
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	// Create vSphere client
	c, err := vsphereLogin(i.cfg, ctx)
	if err != nil {
		return "", err
	}
	defer c.Logout(ctx)

	vm, err := getVirtualMachineByName(i.cfg, ctx, c, name)

	var mvm mo.VirtualMachine
	err = getVirtualMachineManagedObjectReference(ctx, c, vm, "summary", &mvm)
	if err != nil {
		return "", err
	}

	if mvm.Summary.Runtime.PowerState == ActivePowerState {
		return "/" + vm.InventoryPath, nil
	}

	if mvm.Summary.Config.Template == false {
		glog.Warning("VM %s, is not in %s state", name, ActivePowerState)
	} else {
		glog.Warning("VM %s, is a template", name)
	}

	return "", cloudprovider.InstanceNotFound
}

func (i *Instances) InstanceType(name string) (string, error) {
	return "", nil
}

func (vs *VSphere) Clusters() (cloudprovider.Clusters, bool) {
	return nil, true
}

// ProviderName returns the cloud provider ID.
func (vs *VSphere) ProviderName() string {
	return ProviderName
}

// LoadBalancer returns an implementation of LoadBalancer for vSphere.
func (vs *VSphere) LoadBalancer() (cloudprovider.LoadBalancer, bool) {
	return nil, false
}

// Zones returns an implementation of Zones for Google vSphere.
func (vs *VSphere) Zones() (cloudprovider.Zones, bool) {
	glog.V(4).Info("Claiming to support Zones")

	return vs, true
}

func (vs *VSphere) GetZone() (cloudprovider.Zone, error) {
	glog.V(4).Infof("Current zone is %v", vs.cfg.Global.Datacenter)

	return cloudprovider.Zone{Region: vs.cfg.Global.Datacenter}, nil
}

// Routes returns an implementation of Routes for vSphere.
func (vs *VSphere) Routes() (cloudprovider.Routes, bool) {
	return nil, true
}

// ScrubDNS filters DNS settings for pods.
func (vs *VSphere) ScrubDNS(nameservers, searches []string) (nsOut, srchOut []string) {
	return nameservers, searches
}