package azure

import (
	"errors"
	"fmt"
	"net"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"time"

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

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

const (
	dockerConfigDir = "/etc/docker"
)

type Driver struct {
	MachineName             string
	SubscriptionID          string
	SubscriptionCert        string
	PublishSettingsFilePath string
	Location                string
	Size                    string
	UserName                string
	UserPassword            string
	Image                   string
	SSHPort                 int
	DockerPort              int
	CaCertPath              string
	PrivateKeyPath          string
	SwarmMaster             bool
	SwarmHost               string
	SwarmDiscovery          string
	storePath               string
}

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

// GetCreateFlags registers the flags this driver 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) {
	driver := &Driver{MachineName: machineName, storePath: storePath, CaCertPath: caCert, PrivateKeyPath: privateKey}
	return driver, nil
}

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

func (driver *Driver) SetConfigFromFlags(flags drivers.DriverOptions) error {
	driver.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
		}
		driver.SubscriptionCert = cert
	}

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

	if (driver.SubscriptionID == "" || driver.SubscriptionCert == "") && driver.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 == "" {
		driver.Image = "b39f27a8b8c64d52b05eac6a62ebad85__Ubuntu-14_04_1-LTS-amd64-server-20140927-en-us-30GB"
	} else {
		driver.Image = image
	}

	driver.Location = flags.String("azure-location")
	driver.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")
	}

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

	return nil
}

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

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

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

	return nil
}

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

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

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

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

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

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

	log.Info("Waiting for SSH...")
	log.Debugf("Host: %s SSH Port: %d", driver.getHostname(), driver.SSHPort)
	return ssh.WaitForTCP(fmt.Sprintf("%s:%d", driver.getHostname(), driver.SSHPort))
}

func (driver *Driver) runSSHCommand(command string, retries int) error {
	cmd, err := driver.GetSSHCommand(command)
	if err != nil {
		return err
	}
	if err := cmd.Run(); err != nil {
		if err.Error() == "exit status 255" {
			if retries == 0 {
				return err
			}
			return driver.runSSHCommand(command, retries-1)
		}

		return err
	}

	return nil
}

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

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

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

	dockerVM, err := vmClient.GetVMDeployment(driver.MachineName, driver.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 (driver *Driver) Start() error {
	if err := driver.setUserSubscription(); err != nil {
		return err
	}

	if vmState, err := driver.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", driver.MachineName)

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

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

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

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

	return vmClient.ShutdownRole(driver.MachineName, driver.MachineName, driver.MachineName)
}

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

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

	return vmClient.DeleteHostedService(driver.MachineName)
}

func (driver *Driver) Restart() error {
	err := driver.setUserSubscription()
	if err != nil {
		return err
	}
	if vmState, err := driver.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", driver.MachineName)

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

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

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

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

	return vmClient.ShutdownRole(driver.MachineName, driver.MachineName, driver.MachineName)
}

func (d *Driver) StartDocker() error {
	log.Debug("Starting Docker...")

	cmd, err := d.GetSSHCommand("sudo service docker start")
	if err != nil {
		return err
	}
	return cmd.Run()
}

func (d *Driver) StopDocker() error {
	log.Debug("Stopping Docker...")

	cmd, err := d.GetSSHCommand("sudo service docker stop")
	if err != nil {
		return err
	}
	return cmd.Run()
}

func (d *Driver) GetDockerConfigDir() string {
	return dockerConfigDir
}

func (driver *Driver) GetSSHCommand(args ...string) (*exec.Cmd, error) {
	if err := driver.setUserSubscription(); err != nil {
		return nil, err
	}

	if vmState, err := driver.GetState(); err != nil {
		return nil, err
	} else if vmState == state.Stopped {
		return nil, errors.New("Azure host is stopped. Please start it before using ssh command.")
	}

	return ssh.GetSSHCommand(driver.getHostname(), driver.SSHPort, driver.UserName, driver.sshKeyPath(), args...), nil
}

func (driver *Driver) Upgrade() error {
	log.Debugf("Upgrading Docker")

	cmd, err := driver.GetSSHCommand("sudo apt-get update && sudo apt-get install --upgrade lxc-docker")
	if err != nil {
		return err
	}
	return cmd.Run()
}

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

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

func (driver *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:      driver.DockerPort,
			LocalPort: driver.DockerPort}
		configSets[i].InputEndpoints.InputEndpoint = append(configSets[i].InputEndpoints.InputEndpoint, ep)
		log.Debugf("added Docker endpoint (port %d) to configuration", driver.DockerPort)
	}
	return nil
}

func (driver *Driver) waitForSSH() error {
	log.Infof("Waiting for SSH...")
	return ssh.WaitForTCP(fmt.Sprintf("%s:%v", driver.getHostname(), driver.SSHPort))
}

func (driver *Driver) waitForDocker() error {
	log.Infof("Waiting for docker daemon on host to be available...")
	maxRepeats := 48
	url := fmt.Sprintf("%s:%v", driver.getHostname(), driver.DockerPort)
	success := waitForDockerEndpoint(url, maxRepeats)
	if !success {
		return errors.New("Can not run docker daemon on remote machine. Please try again.")
	}
	return nil
}

func waitForDockerEndpoint(url string, maxRepeats int) bool {
	counter := 0
	for {
		conn, err := net.Dial("tcp", url)
		if err != nil {
			time.Sleep(10 * time.Second)
			counter++
			if counter == maxRepeats {
				return false
			}
			continue
		}
		defer conn.Close()
		break
	}
	return true
}

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

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

func (driver *Driver) sshKeyPath() string {
	return filepath.Join(driver.storePath, "id_rsa")
}

func (driver *Driver) azureCertPath() string {
	return filepath.Join(driver.storePath, "azure_cert.pem")
}

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