package azure

import (
	"errors"
	"fmt"
	"os"
	"os/exec"
	"strings"

	azure "github.com/MSOpenTech/azure-sdk-for-go"
	"github.com/MSOpenTech/azure-sdk-for-go/clients/vmClient"

	"github.com/codegangsta/cli"
	"github.com/docker/machine/drivers"
	"github.com/docker/machine/log"
	"github.com/docker/machine/ssh"
	"github.com/docker/machine/state"
	"github.com/docker/machine/utils"
)

type Driver struct {
	*drivers.BaseDriver
	SubscriptionID          string
	SubscriptionCert        string
	PublishSettingsFilePath string
	Location                string
	Size                    string
	UserPassword            string
	Image                   string
	DockerPort              int
}

func init() {
	drivers.Register("azure", &drivers.RegisteredDriver{
		New:            NewDriver,
		GetCreateFlags: GetCreateFlags,
	})
}

// GetCreateFlags registers the flags this d adds to
// "docker hosts create"
func GetCreateFlags() []cli.Flag {
	return []cli.Flag{
		cli.IntFlag{
			Name:  "azure-docker-port",
			Usage: "Azure Docker port",
			Value: 2376,
		},
		cli.StringFlag{
			EnvVar: "AZURE_IMAGE",
			Name:   "azure-image",
			Usage:  "Azure image name. Default is Ubuntu 14.04 LTS x64",
		},
		cli.StringFlag{
			EnvVar: "AZURE_LOCATION",
			Name:   "azure-location",
			Usage:  "Azure location",
			Value:  "West US",
		},
		cli.StringFlag{
			Name:  "azure-password",
			Usage: "Azure user password",
		},
		cli.StringFlag{
			EnvVar: "AZURE_PUBLISH_SETTINGS_FILE",
			Name:   "azure-publish-settings-file",
			Usage:  "Azure publish settings file",
		},
		cli.StringFlag{
			EnvVar: "AZURE_SIZE",
			Name:   "azure-size",
			Usage:  "Azure size",
			Value:  "Small",
		},
		cli.IntFlag{
			Name:  "azure-ssh-port",
			Usage: "Azure SSH port",
			Value: 22,
		},

		cli.StringFlag{
			EnvVar: "AZURE_SUBSCRIPTION_CERT",
			Name:   "azure-subscription-cert",
			Usage:  "Azure subscription cert",
		},
		cli.StringFlag{
			EnvVar: "AZURE_SUBSCRIPTION_ID",
			Name:   "azure-subscription-id",
			Usage:  "Azure subscription ID",
		},
		cli.StringFlag{
			Name:  "azure-username",
			Usage: "Azure username",
			Value: "ubuntu",
		},
	}
}

func NewDriver(machineName string, storePath string, caCert string, privateKey string) (drivers.Driver, error) {
	inner := drivers.NewBaseDriver(machineName, storePath, caCert, privateKey)
	d := &Driver{BaseDriver: inner}
	return d, nil
}

func (d *Driver) GetSSHHostname() (string, error) {
	return d.GetIP()
}

func (d *Driver) GetSSHUsername() string {
	if d.SSHUser == "" {
		d.SSHUser = "ubuntu"
	}

	return d.SSHUser
}

func (d *Driver) DriverName() string {
	return "azure"
}

func (d *Driver) SetConfigFromFlags(flags drivers.DriverOptions) error {
	d.SubscriptionID = flags.String("azure-subscription-id")

	cert := flags.String("azure-subscription-cert")
	publishSettings := flags.String("azure-publish-settings-file")
	image := flags.String("azure-image")
	username := flags.String("azure-username")

	if cert != "" {
		if _, err := os.Stat(cert); os.IsNotExist(err) {
			return err
		}
		d.SubscriptionCert = cert
	}

	if publishSettings != "" {
		if _, err := os.Stat(publishSettings); os.IsNotExist(err) {
			return err
		}
		d.PublishSettingsFilePath = publishSettings
	}

	if (d.SubscriptionID == "" || d.SubscriptionCert == "") && d.PublishSettingsFilePath == "" {
		return errors.New("Please specify azure subscription params using options: --azure-subscription-id and --azure-subscription-cert or --azure-publish-settings-file")
	}

	if image == "" {
		d.Image = "b39f27a8b8c64d52b05eac6a62ebad85__Ubuntu-14_04_1-LTS-amd64-server-20140927-en-us-30GB"
	} else {
		d.Image = image
	}

	d.Location = flags.String("azure-location")
	d.Size = flags.String("azure-size")

	if strings.ToLower(username) == "docker" {
		return errors.New("'docker' is not valid user name for docker host. Please specify another user name")
	}

	d.SSHUser = username
	d.UserPassword = flags.String("azure-password")
	d.DockerPort = flags.Int("azure-docker-port")
	d.SSHPort = flags.Int("azure-ssh-port")
	d.SwarmMaster = flags.Bool("swarm-master")
	d.SwarmHost = flags.String("swarm-host")
	d.SwarmDiscovery = flags.String("swarm-discovery")

	return nil
}

func (d *Driver) PreCreateCheck() error {
	if err := d.setUserSubscription(); err != nil {
		return err
	}

	// check azure DNS to make sure name is available
	available, response, err := vmClient.CheckHostedServiceNameAvailability(d.MachineName)
	if err != nil {
		return err
	}

	if !available {
		return errors.New(response)
	}

	return nil
}

func (d *Driver) Create() error {
	if err := d.setUserSubscription(); err != nil {
		return err
	}

	log.Info("Creating Azure machine...")
	vmConfig, err := vmClient.CreateAzureVMConfiguration(d.MachineName, d.Size, d.Image, d.Location)
	if err != nil {
		return err
	}

	log.Debug("Generating certificate for Azure...")
	if err := d.generateCertForAzure(); err != nil {
		return err
	}

	log.Debug("Adding Linux provisioning...")
	vmConfig, err = vmClient.AddAzureLinuxProvisioningConfig(vmConfig, d.GetSSHUsername(), d.UserPassword, d.azureCertPath(), d.SSHPort)
	if err != nil {
		return err
	}

	log.Debug("Authorizing ports...")
	if err := d.addDockerEndpoint(vmConfig); err != nil {
		return err
	}

	log.Debug("Creating VM...")
	if err := vmClient.CreateAzureVM(vmConfig, d.MachineName, d.Location); err != nil {
		return err
	}

	return nil
}

func (d *Driver) GetURL() (string, error) {
	url := fmt.Sprintf("tcp://%s:%v", d.getHostname(), d.DockerPort)
	return url, nil
}

func (d *Driver) GetIP() (string, error) {
	return d.getHostname(), nil
}

func (d *Driver) GetState() (state.State, error) {
	if err := d.setUserSubscription(); err != nil {
		return state.Error, err
	}

	dockerVM, err := vmClient.GetVMDeployment(d.MachineName, d.MachineName)
	if err != nil {
		if strings.Contains(err.Error(), "Code: ResourceNotFound") {
			return state.Error, errors.New("Azure host was not found. Please check your Azure subscription.")
		}

		return state.Error, err
	}

	vmState := dockerVM.RoleInstanceList.RoleInstance[0].PowerState
	switch vmState {
	case "Started":
		return state.Running, nil
	case "Starting":
		return state.Starting, nil
	case "Stopped":
		return state.Stopped, nil
	}

	return state.None, nil
}

func (d *Driver) Start() error {
	if err := d.setUserSubscription(); err != nil {
		return err
	}

	if vmState, err := d.GetState(); err != nil {
		return err
	} else if vmState == state.Running || vmState == state.Starting {
		log.Infof("Host is already running or starting")
		return nil
	}

	log.Debugf("starting %s", d.MachineName)

	if err := vmClient.StartRole(d.MachineName, d.MachineName, d.MachineName); err != nil {
		return err
	}

	var err error
	d.IPAddress, err = d.GetIP()
	return err
}

func (d *Driver) Stop() error {
	if err := d.setUserSubscription(); err != nil {
		return err
	}

	if vmState, err := d.GetState(); err != nil {
		return err
	} else if vmState == state.Stopped {
		log.Infof("Host is already stopped")
		return nil
	}

	log.Debugf("stopping %s", d.MachineName)

	if err := vmClient.ShutdownRole(d.MachineName, d.MachineName, d.MachineName); err != nil {
		return err
	}

	d.IPAddress = ""
	return nil
}

func (d *Driver) Remove() error {
	if err := d.setUserSubscription(); err != nil {
		return err
	}
	if available, _, err := vmClient.CheckHostedServiceNameAvailability(d.MachineName); err != nil {
		return err
	} else if available {
		return nil
	}

	log.Debugf("removing %s", d.MachineName)

	return vmClient.DeleteHostedService(d.MachineName)
}

func (d *Driver) Restart() error {
	err := d.setUserSubscription()
	if err != nil {
		return err
	}
	if vmState, err := d.GetState(); err != nil {
		return err
	} else if vmState == state.Stopped {
		return errors.New("Host is already stopped, use start command to run it")
	}

	log.Debugf("restarting %s", d.MachineName)

	if err := vmClient.RestartRole(d.MachineName, d.MachineName, d.MachineName); err != nil {
		return err
	}

	d.IPAddress, err = d.GetIP()
	return err
}

func (d *Driver) Kill() error {
	if err := d.setUserSubscription(); err != nil {
		return err
	}

	if vmState, err := d.GetState(); err != nil {
		return err
	} else if vmState == state.Stopped {
		log.Infof("Host is already stopped")
		return nil
	}

	log.Debugf("killing %s", d.MachineName)

	if err := vmClient.ShutdownRole(d.MachineName, d.MachineName, d.MachineName); err != nil {
		return err
	}

	d.IPAddress = ""
	return nil
}

func generateVMName() string {
	randomID := utils.TruncateID(utils.GenerateRandomID())
	return fmt.Sprintf("docker-host-%s", randomID)
}

func (d *Driver) setUserSubscription() error {
	if d.PublishSettingsFilePath != "" {
		return azure.ImportPublishSettingsFile(d.PublishSettingsFilePath)
	}
	return azure.ImportPublishSettings(d.SubscriptionID, d.SubscriptionCert)
}

func (d *Driver) addDockerEndpoint(vmConfig *vmClient.Role) error {
	configSets := vmConfig.ConfigurationSets.ConfigurationSet
	if len(configSets) == 0 {
		return errors.New("no configuration set")
	}
	for i := 0; i < len(configSets); i++ {
		if configSets[i].ConfigurationSetType != "NetworkConfiguration" {
			continue
		}
		ep := vmClient.InputEndpoint{
			Name:      "docker",
			Protocol:  "tcp",
			Port:      d.DockerPort,
			LocalPort: d.DockerPort}
		configSets[i].InputEndpoints.InputEndpoint = append(configSets[i].InputEndpoints.InputEndpoint, ep)
		log.Debugf("added Docker endpoint (port %d) to configuration", d.DockerPort)
	}
	return nil
}

func (d *Driver) generateCertForAzure() error {
	if err := ssh.GenerateSSHKey(d.GetSSHKeyPath()); err != nil {
		return err
	}

	cmd := exec.Command("openssl", "req", "-x509", "-key", d.GetSSHKeyPath(), "-nodes", "-days", "365", "-newkey", "rsa:2048", "-out", d.azureCertPath(), "-subj", "/C=AU/ST=Some-State/O=InternetWidgitsPtyLtd/CN=\\*")
	return cmd.Run()
}

func (d *Driver) azureCertPath() string {
	return d.ResolveStorePath("azure_cert.pem")
}

func (d *Driver) getHostname() string {
	return d.MachineName + ".cloudapp.net"
}