func permsList(argv []string) error {
	usage := `
Lists all users with permission to use an app, or lists all users with system
administrator privileges.

Usage: deis perms:list [-a --app=<app>|--admin]

Options:
  -a --app=<app>
    lists all users with permission to <app>. <app> is the uniquely identifiable name
    for the application.
  --admin
    lists all users with system administrator privileges.
`

	args, err := docopt.Parse(usage, argv, true, "", false, true)

	if err != nil {
		return err
	}

	admin := args["--admin"].(bool)

	return cmd.PermsList(safeGetValue(args, "--app"), admin)
}

func releasesInfo(argv []string) error {
	usage := `
Prints info about a particular release.

Usage: deis releases:info <version> [options]

Arguments:
  <version>
    the release of the application, such as 'v1'.

Options:
  -a --app=<app>
    the uniquely identifiable name for the application.
`

	args, err := docopt.Parse(usage, argv, true, "", false, true)

	version, err := versionFromString(args["<version>"].(string))

	if err != nil {
		return err
	}

	return cmd.ReleasesInfo(safeGetValue(args, "--app"), version)
}

func tagsSet(argv []string) error {
	usage := `
Sets tags for an application.

A tag is a key/value pair used to tag an application's containers and is passed to the
scheduler. This is often used to restrict workloads to specific hosts matching the
scheduler-configured metadata.

Usage: deis tags:set [options] <key>=<value>...

Arguments:
  <key> the tag key, for example: "environ" or "rack"
  <value> the tag value, for example: "prod" or "1"

Options:
  -a --app=<app>
    the uniquely identifiable name for the application.
`

	args, err := docopt.Parse(usage, argv, true, "", false, true)

	if err != nil {
		return err
	}

	app := safeGetValue(args, "--app")
	tags := args["<key>=<value>"].([]string)

	return cmd.TagsSet(app, tags)
}

// Start activates the specified components.
func Start(argv []string, b backend.Backend) error {
	usage := `Activates the specified components.

Usage:
  deisctl start [<target>...] [options]
`
	// parse command-line arguments
	args, err := docopt.Parse(usage, argv, true, "", false)
	if err != nil {
		return err
	}

	// if target is platform, install all services
	targets := args["<target>"].([]string)

	if len(targets) == 1 && targets[0] == PlatformCommand {
		return StartPlatform(b)
	}

	outchan := make(chan string)
	errchan := make(chan error)
	var wg sync.WaitGroup

	go printState(outchan, errchan, 500*time.Millisecond)

	b.Start(targets, &wg, outchan, errchan)
	wg.Wait()
	close(outchan)

	return nil
}

func authCancel(argv []string) error {
	usage := `
Cancels and removes the current account.

Usage: deis auth:cancel [options]

Options:
  --username=<username>
    provide a username for the account.
  --password=<password>
    provide a password for the account.
  --yes
    force "yes" when prompted.
`

	args, err := docopt.Parse(usage, argv, true, "", false, true)

	if err != nil {
		return err
	}

	username := safeGetValue(args, "--username")
	password := safeGetValue(args, "--password")
	yes := args["--yes"].(bool)

	return cmd.Cancel(username, password, yes)
}

func permsList(argv []string) error {
	usage := `
Lists all users with permission to use an app, or lists all users with system
administrator privileges.

Usage: deis perms:list [-a --app=<app>|--admin|--admin --limit=<num>]

Options:
  -a --app=<app>
    lists all users with permission to <app>. <app> is the uniquely identifiable name
    for the application.
  --admin
    lists all users with system administrator privileges.
  -l --limit=<num>
    the maximum number of results to display, defaults to config setting
`

	args, err := docopt.Parse(usage, argv, true, "", false, true)

	if err != nil {
		return err
	}

	admin := args["--admin"].(bool)

	results, err := responseLimit(safeGetValue(args, "--limit"))

	if err != nil {
		return err
	}

	return cmd.PermsList(safeGetValue(args, "--app"), admin, results)
}

// Uninstall unloads the definitions of the specified components.
// After Uninstall, the components will be unavailable until Install is called.
func Uninstall(argv []string, b backend.Backend) error {
	usage := `Unloads the definitions of the specified components.

After uninstall, the components will be unavailable until install is called.

Usage:
  deisctl uninstall [<target>...] [options]
`
	// parse command-line arguments
	args, err := docopt.Parse(usage, argv, true, "", false)
	if err != nil {
		return err
	}

	// if target is platform, uninstall all services
	targets := args["<target>"].([]string)
	if len(targets) == 1 && targets[0] == PlatformCommand {
		return UninstallPlatform(b)
	}

	outchan := make(chan string)
	errchan := make(chan error)
	var wg sync.WaitGroup

	go printState(outchan, errchan, 500*time.Millisecond)

	// uninstall the specific target
	b.Destroy(targets, &wg, outchan, errchan)
	wg.Wait()
	close(outchan)

	return nil
}

func appRun(argv []string) error {
	usage := `
Runs a command inside an ephemeral app container. Default environment is
/bin/bash.

Usage: deis apps:run [options] [--] <command>...

Arguments:
  <command>
    the shell command to run inside the container.

Options:
  -a --app=<app>
    the uniquely identifiable name for the application.
`
	args, err := docopt.Parse(usage, argv, true, "", false, true)

	if err != nil {
		return err
	}

	app := safeGetValue(args, "--app")
	command := strings.Join(args["<command>"].([]string), " ")

	return cmd.AppRun(app, command)
}

func appDestroy(argv []string) error {
	usage := `
Destroys an application.

Usage: deis apps:destroy [options]

Options:
  -a --app=<app>
    the uniquely identifiable name for the application.
  --confirm=<app>
    skips the prompt for the application name. <app> is the uniquely identifiable
    name for the application.

`
	args, err := docopt.Parse(usage, argv, true, "", false, true)

	if err != nil {
		return err
	}

	app := safeGetValue(args, "--app")
	confirm := safeGetValue(args, "--confirm")

	return cmd.AppDestroy(app, confirm)
}

func configSet(argv []string) error {
	usage := `
Sets environment variables for an application.

Usage: deis config:set <var>=<value> [<var>=<value>...] [options]

Arguments:
  <var>
    the uniquely identifiable name for the environment variable.
  <value>
    the value of said environment variable.

Options:
  -a --app=<app>
    the uniquely identifiable name for the application.
`

	args, err := docopt.Parse(usage, argv, true, "", false, true)

	if err != nil {
		return err
	}

	return cmd.ConfigSet(safeGetValue(args, "--app"), args["<var>=<value>"].([]string))
}

func appLogs(argv []string) error {
	usage := `
Retrieves the most recent log events.

Usage: deis apps:logs [options]

Options:
  -a --app=<app>
    the uniquely identifiable name for the application.
  -n --lines=<lines>
    the number of lines to display
`
	args, err := docopt.Parse(usage, argv, true, "", false, true)

	if err != nil {
		return err
	}

	app := safeGetValue(args, "--app")

	linesStr := safeGetValue(args, "--lines")
	var lines int

	if linesStr == "" {
		lines = -1
	} else {
		lines, err = strconv.Atoi(linesStr)

		if err != nil {
			return err
		}
	}

	return cmd.AppLogs(app, lines)
}

func configPull(argv []string) error {
	usage := `
Extract all environment variables from an application for local use.

Your environment will be stored locally in a file named .env. This file can be
read by foreman to load the local environment for your app.

Usage: deis config:pull [options]

Options:
  -a --app=<app>
    The application that you wish to pull from
  -i --interactive
    Prompts for each value to be overwritten
  -o --overwrite
    Allows you to have the pull overwrite keys in .env
`

	args, err := docopt.Parse(usage, argv, true, "", false, true)

	if err != nil {
		return err
	}

	app := safeGetValue(args, "--app")
	interactive := args["--interactive"].(bool)
	overwrite := args["--overwrite"].(bool)

	return cmd.ConfigPull(app, interactive, overwrite)
}

// Update runs the Deis update engine daemon
func Update() error {
	usage := `Deis Update Daemon

	Usage:
	deisctl update [options]

	Options:
	--verbose                   print out the request bodies [default: false]
	--min-sleep=<sec>           minimum time between update checks [default: 10]
	--max-sleep=<sec>           maximum time between update checks [default: 30]
	--server=<server>           alternate update server URL (optional)
	`
	// parse command-line arguments
	args, err := docopt.Parse(usage, nil, true, "", true)
	if err != nil {
		return err
	}
	fmt.Printf("args: %v\n", args)
	err = setUpdateFlags(args)
	if err != nil {
		return err
	}
	fmt.Printf("flags: %v\n", Flags)
	return doUpdate()
}

func psScale(argv []string) error {
	usage := `
Scales an application's processes by type.

Usage: deis ps:scale <type>=<num>... [options]

Arguments:
  <type>
    the process name as defined in your Procfile, such as 'web' or 'worker'.
    Note that Dockerfile apps have a default 'cmd' process type.
  <num>
    the number of processes.

Options:
  -a --app=<app>
    the uniquely identifiable name for the application.
`

	args, err := docopt.Parse(usage, argv, true, "", false, true)

	if err != nil {
		return err
	}

	return cmd.PsScale(safeGetValue(args, "--app"), args["<type>=<num>"].([]string))
}

// SSH opens an interactive shell with a machine in the cluster.
func (c *Client) SSH(argv []string) error {
	usage := `Open an interactive shell on a machine in the cluster given a unit or machine id.

If an optional <command> is provided, that command is run remotely, and the results returned.

Usage:
  deisctl ssh <target> [<command>...]
`
	// parse command-line arguments
	args, err := docopt.Parse(usage, argv, true, "", true)
	if err != nil {
		return err
	}

	target := args["<target>"].(string)
	// handle help explicitly since docopt parsing is relaxed
	if target == "--help" {
		fmt.Println(usage)
		os.Exit(0)
	}

	var vargs []string
	if v, ok := args["<command>"]; ok {
		vargs = v.([]string)
	}

	return cmd.SSH(target, vargs, c.Backend)
}

func appCreate(argv []string) error {
	usage := `
Creates a new application.

- if no <id> is provided, one will be generated automatically.

Usage: deis apps:create [<id>] [options]

Arguments:
  <id>
    a uniquely identifiable name for the application. No other app can already
    exist with this name.

Options:
  --no-remote
    do not create a 'deis' git remote.
  -b --buildpack BUILDPACK
    a buildpack url to use for this app
  -r --remote REMOTE
    name of remote to create. [default: deis]
`
	args, err := docopt.Parse(usage, argv, true, "", false, true)

	if err != nil {
		return err
	}

	id := safeGetValue(args, "<id>")
	buildpack := safeGetValue(args, "--buildpack")
	remote := safeGetValue(args, "--remote")
	noRemote := args["--no-remote"].(bool)

	return cmd.AppCreate(id, buildpack, remote, noRemote)
}

func (c *Client) Dock(argv []string) error {
	usage := `Connect to the named docker container and run commands on it.

This is equivalent to running 'docker exec -it <target> <command>'.

Usage:
  deisctl dock <target> [<command>...]
`
	// parse command-line arguments
	args, err := docopt.Parse(usage, argv, true, "", true)
	if err != nil {
		return err
	}

	target := args["<target>"].(string)
	// handle help explicitly since docopt parsing is relaxed
	if target == "--help" {
		fmt.Println(usage)
		os.Exit(0)
	}

	var vargs []string
	if v, ok := args["<command>"]; ok {
		vargs = v.([]string)
	}

	return cmd.Dock(target, vargs, c.Backend)
}

func certsList(argv []string) error {
	usage := `
Show certificate information for an SSL application.

Usage: deis certs:list [options]

Options:
  -l --limit=<num>
    the maximum number of results to display, defaults to config setting
`

	args, err := docopt.Parse(usage, argv, true, "", false, true)

	if err != nil {
		return err
	}

	results, err := responseLimit(safeGetValue(args, "--limit"))

	if err != nil {
		return err
	}

	return cmd.CertsList(results)
}

func permCreate(argv []string) error {
	usage := `
Gives another user permission to use an app, or gives another user
system administrator privileges.

Usage: deis perms:create <username> [-a --app=<app>|--admin]

Arguments:
  <username>
    the name of the new user.

Options:
  -a --app=<app>
    grants <username> permission to use <app>. <app> is the uniquely identifiable name
    for the application.
  --admin
    grants <username> system administrator privileges.
`

	args, err := docopt.Parse(usage, argv, true, "", false, true)

	if err != nil {
		return err
	}

	app := safeGetValue(args, "--app")
	username := args["<username>"].(string)
	admin := args["--admin"].(bool)

	return cmd.PermCreate(app, username, admin)
}

func certAdd(argv []string) error {
	usage := `
Binds a certificate/key pair to an application.

Usage: deis certs:add <cert> <key> [options]

Arguments:
  <cert>
    The public key of the SSL certificate.
  <key>
    The private key of the SSL certificate.

Options:
  --common-name=<cname>
    The common name of the certificate. If none is provided, the controller will
    interpret the common name from the certificate.
  --subject-alt-names=<sans>
    The subject alternate names (SAN) of the certificate, separated by commas. This will
    create multiple Certificate objects in the controller, one for each SAN.
`

	args, err := docopt.Parse(usage, argv, true, "", false, true)

	if err != nil {
		return err
	}

	cert := args["<cert>"].(string)
	key := args["<key>"].(string)
	commonName := safeGetValue(args, "--common-name")
	sans := safeGetValue(args, "--subject-alt-names")

	return cmd.CertAdd(cert, key, commonName, sans)
}