data_entry_flow.py

"""Classes to help gather user submissions."""
from __future__ import annotations

import abc
from collections.abc import Callable, Iterable, Mapping
import copy
from dataclasses import dataclass
import logging
from types import MappingProxyType
from typing import Any, TypedDict

from typing_extensions import Required
import voluptuous as vol

from .backports.enum import StrEnum
from .core import HomeAssistant, callback
from .exceptions import HomeAssistantError
from .helpers.frame import report
from .util import uuid as uuid_util

_LOGGER = logging.getLogger(__name__)


class FlowResultType(StrEnum):
    """Result type for a data entry flow."""

    FORM = "form"
    CREATE_ENTRY = "create_entry"
    ABORT = "abort"
    EXTERNAL_STEP = "external"
    EXTERNAL_STEP_DONE = "external_done"
    SHOW_PROGRESS = "progress"
    SHOW_PROGRESS_DONE = "progress_done"
    MENU = "menu"


# RESULT_TYPE_* is deprecated, to be removed in 2022.9
RESULT_TYPE_FORM = "form"
RESULT_TYPE_CREATE_ENTRY = "create_entry"
RESULT_TYPE_ABORT = "abort"
RESULT_TYPE_EXTERNAL_STEP = "external"
RESULT_TYPE_EXTERNAL_STEP_DONE = "external_done"
RESULT_TYPE_SHOW_PROGRESS = "progress"
RESULT_TYPE_SHOW_PROGRESS_DONE = "progress_done"
RESULT_TYPE_MENU = "menu"

# Event that is fired when a flow is progressed via external or progress source.
EVENT_DATA_ENTRY_FLOW_PROGRESSED = "data_entry_flow_progressed"


@dataclass
class BaseServiceInfo:
    """Base class for discovery ServiceInfo."""


class FlowError(HomeAssistantError):
    """Base class for data entry errors."""


class UnknownHandler(FlowError):
    """Unknown handler specified."""


class UnknownFlow(FlowError):
    """Unknown flow specified."""


class UnknownStep(FlowError):
    """Unknown step specified."""


class AbortFlow(FlowError):
    """Exception to indicate a flow needs to be aborted."""

    def __init__(
        self, reason: str, description_placeholders: Mapping[str, str] | None = None
    ) -> None:
        """Initialize an abort flow exception."""
        super().__init__(f"Flow aborted: {reason}")
        self.reason = reason
        self.description_placeholders = description_placeholders


class FlowResult(TypedDict, total=False):
    """Typed result dict."""

    context: dict[str, Any]
    data_schema: vol.Schema | None
    data: Mapping[str, Any]
    description_placeholders: Mapping[str, str | None] | None
    description: str | None
    errors: dict[str, str] | None
    extra: str
    flow_id: Required[str]
    handler: Required[str]
    last_step: bool | None
    menu_options: list[str] | dict[str, str]
    options: Mapping[str, Any]
    progress_action: str
    reason: str
    required: bool
    result: Any
    step_id: str
    title: str
    type: FlowResultType
    url: str
    version: int


@callback
def _async_flow_handler_to_flow_result(
    flows: Iterable[FlowHandler], include_uninitialized: bool
) -> list[FlowResult]:
    """Convert a list of FlowHandler to a partial FlowResult that can be serialized."""
    results = []
    for flow in flows:
        if not include_uninitialized and flow.cur_step is None:
            continue
        result = FlowResult(
            flow_id=flow.flow_id,
            handler=flow.handler,
            context=flow.context,
        )
        if flow.cur_step:
            result["step_id"] = flow.cur_step["step_id"]
        results.append(result)
    return results


class FlowManager(abc.ABC):
    """Manage all the flows that are in progress."""

    def __init__(
        self,
        hass: HomeAssistant,
    ) -> None:
        """Initialize the flow manager."""
        self.hass = hass
        self._progress: dict[str, FlowHandler] = {}
        self._handler_progress_index: dict[str, set[str]] = {}
        self._init_data_process_index: dict[type, set[str]] = {}

    @abc.abstractmethod
    async def async_create_flow(
        self,
        handler_key: str,
        *,
        context: dict[str, Any] | None = None,
        data: dict[str, Any] | None = None,
    ) -> FlowHandler:
        """Create a flow for specified handler.

        Handler key is the domain of the component that we want to set up.
        """

    @abc.abstractmethod
    async def async_finish_flow(
        self, flow: FlowHandler, result: FlowResult
    ) -> FlowResult:
        """Finish a data entry flow."""

    async def async_post_init(self, flow: FlowHandler, result: FlowResult) -> None:
        """Entry has finished executing its first step asynchronously."""

    @callback
    def async_has_matching_flow(
        self, handler: str, context: dict[str, Any], data: Any
    ) -> bool:
        """Check if an existing matching flow is in progress.

        A flow with the same handler, context, and data.
        """
        return any(
            flow
            for flow in self._async_progress_by_handler(handler)
            if flow.context["source"] == context["source"] and flow.init_data == data
        )

    @callback
    def async_get(self, flow_id: str) -> FlowResult:
        """Return a flow in progress as a partial FlowResult."""
        if (flow := self._progress.get(flow_id)) is None:
            raise UnknownFlow
        return _async_flow_handler_to_flow_result([flow], False)[0]

    @callback
    def async_progress(self, include_uninitialized: bool = False) -> list[FlowResult]:
        """Return the flows in progress as a partial FlowResult."""
        return _async_flow_handler_to_flow_result(
            self._progress.values(), include_uninitialized
        )

    @callback
    def async_progress_by_handler(
        self, handler: str, include_uninitialized: bool = False
    ) -> list[FlowResult]:
        """Return the flows in progress by handler as a partial FlowResult."""
        return _async_flow_handler_to_flow_result(
            self._async_progress_by_handler(handler), include_uninitialized
        )

    @callback
    def async_progress_by_init_data_type(
        self,
        init_data_type: type,
        matcher: Callable[[Any], bool],
        include_uninitialized: bool = False,
    ) -> list[FlowResult]:
        """Return flows in progress init matching by data type as a partial FlowResult."""
        return _async_flow_handler_to_flow_result(
            (
                self._progress[flow_id]
                for flow_id in self._init_data_process_index.get(init_data_type, {})
                if matcher(self._progress[flow_id].init_data)
            ),
            include_uninitialized,
        )

    @callback
    def _async_progress_by_handler(self, handler: str) -> list[FlowHandler]:
        """Return the flows in progress by handler."""
        return [
            self._progress[flow_id]
            for flow_id in self._handler_progress_index.get(handler, {})
        ]

    async def async_init(
        self, handler: str, *, context: dict[str, Any] | None = None, data: Any = None
    ) -> FlowResult:
        """Start a data entry flow."""
        if context is None:
            context = {}
        flow = await self.async_create_flow(handler, context=context, data=data)
        if not flow:
            raise UnknownFlow("Flow was not created")
        flow.hass = self.hass
        flow.handler = handler
        flow.flow_id = uuid_util.random_uuid_hex()
        flow.context = context
        flow.init_data = data
        self._async_add_flow_progress(flow)

        result = await self._async_handle_step(flow, flow.init_step, data)

        if result["type"] != FlowResultType.ABORT:
            await self.async_post_init(flow, result)

        return result

    async def async_configure(
        self, flow_id: str, user_input: dict | None = None
    ) -> FlowResult:
        """Continue a data entry flow."""
        if (flow := self._progress.get(flow_id)) is None:
            raise UnknownFlow

        cur_step = flow.cur_step
        assert cur_step is not None

        if (
            data_schema := cur_step.get("data_schema")
        ) is not None and user_input is not None:
            user_input = data_schema(user_input)

        # Handle a menu navigation choice
        if cur_step["type"] == FlowResultType.MENU and user_input:
            result = await self._async_handle_step(
                flow, user_input["next_step_id"], None
            )
        else:
            result = await self._async_handle_step(
                flow, cur_step["step_id"], user_input
            )

        if cur_step["type"] in (
            FlowResultType.EXTERNAL_STEP,
            FlowResultType.SHOW_PROGRESS,
        ):
            if cur_step["type"] == FlowResultType.EXTERNAL_STEP and result[
                "type"
            ] not in (
                FlowResultType.EXTERNAL_STEP,
                FlowResultType.EXTERNAL_STEP_DONE,
            ):
                raise ValueError(
                    "External step can only transition to "
                    "external step or external step done."
                )
            if cur_step["type"] == FlowResultType.SHOW_PROGRESS and result[
                "type"
            ] not in (
                FlowResultType.SHOW_PROGRESS,
                FlowResultType.SHOW_PROGRESS_DONE,
            ):
                raise ValueError(
                    "Show progress can only transition to show progress or show"
                    " progress done."
                )

            # If the result has changed from last result, fire event to update
            # the frontend.
            if (
                cur_step["step_id"] != result.get("step_id")
                or result["type"] == FlowResultType.SHOW_PROGRESS
            ):
                # Tell frontend to reload the flow state.
                self.hass.bus.async_fire(
                    EVENT_DATA_ENTRY_FLOW_PROGRESSED,
                    {"handler": flow.handler, "flow_id": flow_id, "refresh": True},
                )

        return result

    @callback
    def async_abort(self, flow_id: str) -> None:
        """Abort a flow."""
        self._async_remove_flow_progress(flow_id)

    @callback
    def _async_add_flow_progress(self, flow: FlowHandler) -> None:
        """Add a flow to in progress."""
        if flow.init_data is not None:
            init_data_type = type(flow.init_data)
            self._init_data_process_index.setdefault(init_data_type, set()).add(
                flow.flow_id
            )
        self._progress[flow.flow_id] = flow
        self._handler_progress_index.setdefault(flow.handler, set()).add(flow.flow_id)

    @callback
    def _async_remove_flow_from_index(self, flow: FlowHandler) -> None:
        """Remove a flow from in progress."""
        if flow.init_data is not None:
            init_data_type = type(flow.init_data)
            self._init_data_process_index[init_data_type].remove(flow.flow_id)
            if not self._init_data_process_index[init_data_type]:
                del self._init_data_process_index[init_data_type]
        handler = flow.handler
        self._handler_progress_index[handler].remove(flow.flow_id)
        if not self._handler_progress_index[handler]:
            del self._handler_progress_index[handler]

    @callback
    def _async_remove_flow_progress(self, flow_id: str) -> None:
        """Remove a flow from in progress."""
        if (flow := self._progress.pop(flow_id, None)) is None:
            raise UnknownFlow
        self._async_remove_flow_from_index(flow)
        try:
            flow.async_remove()
        except Exception as err:  # pylint: disable=broad-except
            _LOGGER.exception("Error removing %s flow: %s", flow.handler, err)

    async def _async_handle_step(
        self, flow: FlowHandler, step_id: str, user_input: dict | BaseServiceInfo | None
    ) -> FlowResult:
        """Handle a step of a flow."""
        method = f"async_step_{step_id}"

        if not hasattr(flow, method):
            self._async_remove_flow_progress(flow.flow_id)
            raise UnknownStep(
                f"Handler {flow.__class__.__name__} doesn't support step {step_id}"
            )

        try:
            result: FlowResult = await getattr(flow, method)(user_input)
        except AbortFlow as err:
            result = _create_abort_data(
                flow.flow_id, flow.handler, err.reason, err.description_placeholders
            )

        if not isinstance(result["type"], FlowResultType):
            result["type"] = FlowResultType(result["type"])  # type: ignore[unreachable]
            report(
                (
                    "does not use FlowResultType enum for data entry flow result type. "
                    "This is deprecated and will stop working in Home Assistant 2022.9"
                ),
                error_if_core=False,
            )

        if result["type"] in (
            FlowResultType.FORM,
            FlowResultType.EXTERNAL_STEP,
            FlowResultType.EXTERNAL_STEP_DONE,
            FlowResultType.SHOW_PROGRESS,
            FlowResultType.SHOW_PROGRESS_DONE,
            FlowResultType.MENU,
        ):
            flow.cur_step = result
            return result

        # We pass a copy of the result because we're mutating our version
        result = await self.async_finish_flow(flow, result.copy())

        # _async_finish_flow may change result type, check it again
        if result["type"] == FlowResultType.FORM:
            flow.cur_step = result
            return result

        # Abort and Success results both finish the flow
        self._async_remove_flow_progress(flow.flow_id)

        return result


class FlowHandler:
    """Handle a data entry flow."""

    # Set by flow manager
    cur_step: FlowResult | None = None

    # While not purely typed, it makes typehinting more useful for us
    # and removes the need for constant None checks or asserts.
    flow_id: str = None  # type: ignore[assignment]
    hass: HomeAssistant = None  # type: ignore[assignment]
    handler: str = None  # type: ignore[assignment]
    # Ensure the attribute has a subscriptable, but immutable, default value.
    context: dict[str, Any] = MappingProxyType({})  # type: ignore[assignment]

    # Set by _async_create_flow callback
    init_step = "init"

    # The initial data that was used to start the flow
    init_data: Any = None

    # Set by developer
    VERSION = 1

    @property
    def source(self) -> str | None:
        """Source that initialized the flow."""
        return self.context.get("source", None)

    @property
    def show_advanced_options(self) -> bool:
        """If we should show advanced options."""
        return self.context.get("show_advanced_options", False)

    def add_suggested_values_to_schema(
        self, data_schema: vol.Schema, suggested_values: Mapping[str, Any] | None
    ) -> vol.Schema:
        """Make a copy of the schema, populated with suggested values.

        For each schema marker matching items in `suggested_values`,
        the `suggested_value` will be set. The existing `suggested_value` will
        be left untouched if there is no matching item.
        """
        schema = {}
        for key, val in data_schema.schema.items():
            if isinstance(key, vol.Marker):
                # Exclude advanced field
                if (
                    key.description
                    and key.description.get("advanced")
                    and not self.show_advanced_options
                ):
                    continue

            new_key = key
            if (
                suggested_values
                and key in suggested_values
                and isinstance(key, vol.Marker)
            ):
                # Copy the marker to not modify the flow schema
                new_key = copy.copy(key)
                new_key.description = {"suggested_value": suggested_values[key]}
            schema[new_key] = val
        return vol.Schema(schema)

    @callback
    def async_show_form(
        self,
        *,
        step_id: str,
        data_schema: vol.Schema | None = None,
        errors: dict[str, str] | None = None,
        description_placeholders: Mapping[str, str | None] | None = None,
        last_step: bool | None = None,
    ) -> FlowResult:
        """Return the definition of a form to gather user input."""
        return FlowResult(
            type=FlowResultType.FORM,
            flow_id=self.flow_id,
            handler=self.handler,
            step_id=step_id,
            data_schema=data_schema,
            errors=errors,
            description_placeholders=description_placeholders,
            last_step=last_step,  # Display next or submit button in frontend
        )

    @callback
    def async_create_entry(
        self,
        *,
        title: str | None = None,
        data: Mapping[str, Any],
        description: str | None = None,
        description_placeholders: Mapping[str, str] | None = None,
    ) -> FlowResult:
        """Finish flow."""
        flow_result = FlowResult(
            version=self.VERSION,
            type=FlowResultType.CREATE_ENTRY,
            flow_id=self.flow_id,
            handler=self.handler,
            data=data,
            description=description,
            description_placeholders=description_placeholders,
            context=self.context,
        )
        if title is not None:
            flow_result["title"] = title
        return flow_result

    @callback
    def async_abort(
        self,
        *,
        reason: str,
        description_placeholders: Mapping[str, str] | None = None,
    ) -> FlowResult:
        """Abort the flow."""
        return _create_abort_data(
            self.flow_id, self.handler, reason, description_placeholders
        )

    @callback
    def async_external_step(
        self,
        *,
        step_id: str,
        url: str,
        description_placeholders: Mapping[str, str] | None = None,
    ) -> FlowResult:
        """Return the definition of an external step for the user to take."""
        return FlowResult(
            type=FlowResultType.EXTERNAL_STEP,
            flow_id=self.flow_id,
            handler=self.handler,
            step_id=step_id,
            url=url,
            description_placeholders=description_placeholders,
        )

    @callback
    def async_external_step_done(self, *, next_step_id: str) -> FlowResult:
        """Return the definition of an external step for the user to take."""
        return FlowResult(
            type=FlowResultType.EXTERNAL_STEP_DONE,
            flow_id=self.flow_id,
            handler=self.handler,
            step_id=next_step_id,
        )

    @callback
    def async_show_progress(
        self,
        *,
        step_id: str,
        progress_action: str,
        description_placeholders: Mapping[str, str] | None = None,
    ) -> FlowResult:
        """Show a progress message to the user, without user input allowed."""
        return FlowResult(
            type=FlowResultType.SHOW_PROGRESS,
            flow_id=self.flow_id,
            handler=self.handler,
            step_id=step_id,
            progress_action=progress_action,
            description_placeholders=description_placeholders,
        )

    @callback
    def async_show_progress_done(self, *, next_step_id: str) -> FlowResult:
        """Mark the progress done."""
        return FlowResult(
            type=FlowResultType.SHOW_PROGRESS_DONE,
            flow_id=self.flow_id,
            handler=self.handler,
            step_id=next_step_id,
        )

    @callback
    def async_show_menu(
        self,
        *,
        step_id: str,
        menu_options: list[str] | dict[str, str],
        description_placeholders: Mapping[str, str] | None = None,
    ) -> FlowResult:
        """Show a navigation menu to the user.

        Options dict maps step_id => i18n label
        """
        return FlowResult(
            type=FlowResultType.MENU,
            flow_id=self.flow_id,
            handler=self.handler,
            step_id=step_id,
            data_schema=vol.Schema({"next_step_id": vol.In(menu_options)}),
            menu_options=menu_options,
            description_placeholders=description_placeholders,
        )

    @callback
    def async_remove(self) -> None:
        """Notification that the flow has been removed."""


@callback
def _create_abort_data(
    flow_id: str,
    handler: str,
    reason: str,
    description_placeholders: Mapping[str, str] | None = None,
) -> FlowResult:
    """Return the definition of an external step for the user to take."""
    return FlowResult(
        type=FlowResultType.ABORT,
        flow_id=flow_id,
        handler=handler,
        reason=reason,
        description_placeholders=description_placeholders,
    )