text: """Config flow for Transmission Bittorent Client."""
  import voluptuous as vol
  
  from homeassistant import config_entries
  from homeassistant.const import (
      CONF_HOST,
      CONF_NAME,
      CONF_PASSWORD,
      CONF_PORT,
      CONF_SCAN_INTERVAL,
      CONF_USERNAME,
  )
  from homeassistant.core import callback
  
  from . import get_api
  from .const import DEFAULT_NAME, DEFAULT_PORT, DEFAULT_SCAN_INTERVAL, DOMAIN
  from .errors import AuthenticationError, CannotConnect, UnknownError
  
  
  class TransmissionFlowHandler(config_entries.ConfigFlow, domain=DOMAIN):
      """Handle a UniFi config flow."""
  
      VERSION = 1
      CONNECTION_CLASS = config_entries.CONN_CLASS_LOCAL_POLL
  
      @staticmethod
      @callback
      def async_get_options_flow(config_entry):
          """Get the options flow for this handler."""
          return TransmissionOptionsFlowHandler(config_entry)
  
      def __init__(self):
          """Initialize the Transmission flow."""
          self.config = {}
          self.errors = {}
  
      async def async_step_user(self, user_input=None):
          """Handle a flow initialized by the user."""
          if self.hass.config_entries.async_entries(DOMAIN):
              return self.async_abort(reason="one_instance_allowed")
  
          if user_input is not None:
  
              self.config[CONF_NAME] = user_input.pop(CONF_NAME)
              try:
                  await get_api(self.hass, **user_input)
                  self.config.update(user_input)
                  if "options" not in self.config:
                      self.config["options"] = {CONF_SCAN_INTERVAL: DEFAULT_SCAN_INTERVAL}
                  return self.async_create_entry(
                      title=self.config[CONF_NAME], data=self.config
                  )
              except AuthenticationError:
                  self.errors[CONF_USERNAME] = "wrong_credentials"
                  self.errors[CONF_PASSWORD] = "wrong_credentials"
              except (CannotConnect, UnknownError):
                  self.errors["base"] = "cannot_connect"
  
          return self.async_show_form(
              step_id="user",
              data_schema=vol.Schema(
                  {
                      vol.Required(CONF_NAME, default=DEFAULT_NAME): str,
                      vol.Required(CONF_HOST): str,
                      vol.Optional(CONF_USERNAME): str,
                      vol.Optional(CONF_PASSWORD): str,
                      vol.Required(CONF_PORT, default=DEFAULT_PORT): int,
                  }
              ),
              errors=self.errors,
          )
  
      async def async_step_import(self, import_config):
          """Import from Transmission client config."""
          self.config["options"] = {
              CONF_SCAN_INTERVAL: import_config.pop(CONF_SCAN_INTERVAL).seconds
          }
  
          return await self.async_step_user(user_input=import_config)
  
  
  class TransmissionOptionsFlowHandler(config_entries.OptionsFlow):
      """Handle Transmission client options."""
  
      def __init__(self, config_entry):
          """Initialize Transmission options flow."""
          self.config_entry = config_entry
  
      async def async_step_init(self, user_input=None):
          """Manage the Transmission options."""
          if user_input is not None:
              return self.async_create_entry(title="", data=user_input)
  
          options = {
              vol.Optional(
                  CONF_SCAN_INTERVAL,
                  default=self.config_entry.options.get(
                      CONF_SCAN_INTERVAL,
                      self.config_entry.data["options"][CONF_SCAN_INTERVAL],
                  ),
              ): int
          }
  
          return self.async_show_form(step_id="init", data_schema=vol.Schema(options))
  