"""Config flow for flume integration."""
import logging
import os

from pyflume import FlumeAuth, FlumeDeviceList
from requests.exceptions import RequestException
import voluptuous as vol

from homeassistant import config_entries, core, exceptions
from homeassistant.const import (
    CONF_CLIENT_ID,
    CONF_CLIENT_SECRET,
    CONF_PASSWORD,
    CONF_USERNAME,
)

from .const import BASE_TOKEN_FILENAME, DOMAIN

_LOGGER = logging.getLogger(__name__)

# If flume ever implements a login page for oauth
# we can use the oauth2 support built into Home Assistant.
#
# Currently they only implement the token endpoint
#
DATA_SCHEMA = vol.Schema(
    {
        vol.Required(CONF_USERNAME): str,
        vol.Required(CONF_PASSWORD): str,
        vol.Required(CONF_CLIENT_ID): str,
        vol.Required(CONF_CLIENT_SECRET): str,
    }
)


def _validate_input(hass: core.HomeAssistant, data: dict, clear_token_file: bool):
    """Validate in the executor."""
    flume_token_full_path = hass.config.path(
        f"{BASE_TOKEN_FILENAME}-{data[CONF_USERNAME]}"
    )
    if clear_token_file and os.path.exists(flume_token_full_path):
        os.unlink(flume_token_full_path)

    return FlumeDeviceList(
        FlumeAuth(
            data[CONF_USERNAME],
            data[CONF_PASSWORD],
            data[CONF_CLIENT_ID],
            data[CONF_CLIENT_SECRET],
            flume_token_file=flume_token_full_path,
        )
    )


async def validate_input(
    hass: core.HomeAssistant, data: dict, clear_token_file: bool = False
):
    """Validate the user input allows us to connect.

    Data has the keys from DATA_SCHEMA with values provided by the user.
    """
    try:
        flume_devices = await hass.async_add_executor_job(
            _validate_input, hass, data, clear_token_file
        )
    except RequestException as err:
        raise CannotConnect from err
    except Exception as err:
        _LOGGER.exception("Auth exception")
        raise InvalidAuth from err
    if not flume_devices or not flume_devices.device_list:
        raise CannotConnect

    # Return info that you want to store in the config entry.
    return {"title": data[CONF_USERNAME]}


class ConfigFlow(config_entries.ConfigFlow, domain=DOMAIN):
    """Handle a config flow for flume."""

    VERSION = 1

    def __init__(self):
        """Init flume config flow."""
        self._reauth_unique_id = None

    async def async_step_user(self, user_input=None):
        """Handle the initial step."""
        errors = {}
        if user_input is not None:
            await self.async_set_unique_id(user_input[CONF_USERNAME])
            self._abort_if_unique_id_configured()

            try:
                info = await validate_input(self.hass, user_input)
                return self.async_create_entry(title=info["title"], data=user_input)
            except CannotConnect:
                errors["base"] = "cannot_connect"
            except InvalidAuth:
                errors[CONF_PASSWORD] = "invalid_auth"

        return self.async_show_form(
            step_id="user", data_schema=DATA_SCHEMA, errors=errors
        )

    async def async_step_reauth(self, user_input=None):
        """Handle reauth."""
        self._reauth_unique_id = self.context["unique_id"]
        return await self.async_step_reauth_confirm()

    async def async_step_reauth_confirm(self, user_input=None):
        """Handle reauth input."""
        errors = {}
        existing_entry = await self.async_set_unique_id(self._reauth_unique_id)
        if user_input is not None:
            new_data = {**existing_entry.data, CONF_PASSWORD: user_input[CONF_PASSWORD]}
            try:
                await validate_input(self.hass, new_data, clear_token_file=True)
            except CannotConnect:
                errors["base"] = "cannot_connect"
            except InvalidAuth:
                errors[CONF_PASSWORD] = "invalid_auth"
            else:
                self.hass.config_entries.async_update_entry(
                    existing_entry, data=new_data
                )
                await self.hass.config_entries.async_reload(existing_entry.entry_id)
                return self.async_abort(reason="reauth_successful")

        return self.async_show_form(
            description_placeholders={
                CONF_USERNAME: existing_entry.data[CONF_USERNAME]
            },
            step_id="reauth_confirm",
            data_schema=vol.Schema(
                {
                    vol.Required(CONF_PASSWORD): str,
                }
            ),
            errors=errors,
        )


class CannotConnect(exceptions.HomeAssistantError):
    """Error to indicate we cannot connect."""


class InvalidAuth(exceptions.HomeAssistantError):
    """Error to indicate there is invalid auth."""