botbuilder-python/libraries/botbuilder-dialogs/botbuilder/dialogs/dialog_context.py

# Copyright (c) Microsoft Corporation. All rights reserved.
# Licensed under the MIT License.

from typing import List, Optional

from botbuilder.core.turn_context import TurnContext
from botbuilder.dialogs.memory import DialogStateManager

from .dialog_event import DialogEvent
from .dialog_events import DialogEvents
from .dialog_set import DialogSet
from .dialog_state import DialogState
from .dialog_turn_status import DialogTurnStatus
from .dialog_turn_result import DialogTurnResult
from .dialog_reason import DialogReason
from .dialog_instance import DialogInstance
from .dialog import Dialog


class DialogContext:
    def __init__(
        self, dialog_set: DialogSet, turn_context: TurnContext, state: DialogState
    ):
        if dialog_set is None:
            raise TypeError("DialogContext(): dialog_set cannot be None.")
        # TODO: Circular dependency with dialog_set: Check type.
        if turn_context is None:
            raise TypeError("DialogContext(): turn_context cannot be None.")
        self._turn_context = turn_context
        self._dialogs = dialog_set
        self._stack = state.dialog_stack
        self.services = {}
        self.parent: DialogContext = None
        self.state = DialogStateManager(self)

    @property
    def dialogs(self) -> DialogSet:
        """Gets the set of dialogs that can be called from this context.

        :param:
        :return DialogSet:
        """
        return self._dialogs

    @property
    def context(self) -> TurnContext:
        """Gets the context for the current turn of conversation.

        :param:
        :return TurnContext:
        """
        return self._turn_context

    @property
    def stack(self) -> List:
        """Gets the current dialog stack.

        :param:
        :return list:
        """
        return self._stack

    @property
    def active_dialog(self):
        """Return the container link in the database.

        :param:
        :return:
        """
        if self._stack:
            return self._stack[0]
        return None

    @property
    def child(self) -> Optional["DialogContext"]:
        """Return the container link in the database.

        :param:
        :return DialogContext:
        """
        # pylint: disable=import-outside-toplevel
        instance = self.active_dialog

        if instance:
            dialog = self.find_dialog_sync(instance.id)

            # This import prevents circular dependency issues
            from .dialog_container import DialogContainer

            if isinstance(dialog, DialogContainer):
                return dialog.create_child_context(self)

        return None

    async def begin_dialog(self, dialog_id: str, options: object = None):
        """
        Pushes a new dialog onto the dialog stack.
        :param dialog_id: ID of the dialog to start
        :param options: (Optional) additional argument(s) to pass to the dialog being started.
        """
        try:
            if not dialog_id:
                raise TypeError("Dialog(): dialog_id cannot be None.")
            # Look up dialog
            dialog = await self.find_dialog(dialog_id)
            if dialog is None:
                raise Exception(
                    "'DialogContext.begin_dialog(): A dialog with an id of '%s' wasn't found."
                    " The dialog must be included in the current or parent DialogSet."
                    " For example, if subclassing a ComponentDialog you can call add_dialog() within your constructor."
                    % dialog_id
                )
            # Push new instance onto stack
            instance = DialogInstance()
            instance.id = dialog_id
            instance.state = {}

            self._stack.insert(0, (instance))

            # Call dialog's begin_dialog() method
            return await dialog.begin_dialog(self, options)
        except Exception as err:
            self.__set_exception_context_data(err)
            raise

    # TODO: Fix options: PromptOptions instead of object
    async def prompt(self, dialog_id: str, options) -> DialogTurnResult:
        """
        Helper function to simplify formatting the options for calling a prompt dialog. This helper will
        take a `PromptOptions` argument and then call.
        :param dialog_id: ID of the prompt to start.
        :param options: Contains a Prompt, potentially a RetryPrompt and if using ChoicePrompt, Choices.
        :return:
        """
        try:
            if not dialog_id:
                raise TypeError("DialogContext.prompt(): dialogId cannot be None.")

            if not options:
                raise TypeError("DialogContext.prompt(): options cannot be None.")

            return await self.begin_dialog(dialog_id, options)
        except Exception as err:
            self.__set_exception_context_data(err)
            raise

    async def continue_dialog(self):
        """
        Continues execution of the active dialog, if there is one, by passing the context object to
        its `Dialog.continue_dialog()` method. You can check `turn_context.responded` after the call completes
        to determine if a dialog was run and a reply was sent to the user.
        :return:
        """
        try:
            # Check for a dialog on the stack
            if self.active_dialog is not None:
                # Look up dialog
                dialog = await self.find_dialog(self.active_dialog.id)
                if not dialog:
                    raise Exception(
                        "DialogContext.continue_dialog(): Can't continue dialog. "
                        "A dialog with an id of '%s' wasn't found."
                        % self.active_dialog.id
                    )

                # Continue execution of dialog
                return await dialog.continue_dialog(self)

            return DialogTurnResult(DialogTurnStatus.Empty)
        except Exception as err:
            self.__set_exception_context_data(err)
            raise

    # TODO: instance is DialogInstance
    async def end_dialog(self, result: object = None):
        """
        Ends a dialog by popping it off the stack and returns an optional result to the dialog's
        parent. The parent dialog is the dialog that started the dialog being ended via a call to
        either "begin_dialog" or "prompt".
        The parent dialog will have its `Dialog.resume_dialog()` method invoked with any returned
        result. If the parent dialog hasn't implemented a `resume_dialog()` method then it will be
        automatically ended as well and the result passed to its parent. If there are no more
        parent dialogs on the stack then processing of the turn will end.
        :param result: (Optional) result to pass to the parent dialogs.
        :return:
        """
        try:
            await self.end_active_dialog(DialogReason.EndCalled)

            # Resume previous dialog
            if self.active_dialog is not None:
                # Look up dialog
                dialog = await self.find_dialog(self.active_dialog.id)
                if not dialog:
                    raise Exception(
                        "DialogContext.EndDialogAsync(): Can't resume previous dialog."
                        " A dialog with an id of '%s' wasn't found."
                        % self.active_dialog.id
                    )

                # Return result to previous dialog
                return await dialog.resume_dialog(self, DialogReason.EndCalled, result)

            return DialogTurnResult(DialogTurnStatus.Complete, result)
        except Exception as err:
            self.__set_exception_context_data(err)
            raise

    async def cancel_all_dialogs(
        self,
        cancel_parents: bool = None,
        event_name: str = None,
        event_value: object = None,
    ):
        """
        Deletes any existing dialog stack thus cancelling all dialogs on the stack.
        :param cancel_parents:
        :param event_name:
        :param event_value:
        :return:
        """
        try:
            event_name = event_name or DialogEvents.cancel_dialog
            if self.stack or self.parent:
                # Cancel all local and parent dialogs while checking for interception
                notify = False
                dialog_context = self

                while dialog_context:
                    if dialog_context.stack:
                        # Check to see if the dialog wants to handle the event
                        if notify:
                            event_handled = await dialog_context.emit_event(
                                event_name,
                                event_value,
                                bubble=False,
                                from_leaf=False,
                            )

                            if event_handled:
                                break

                        # End the active dialog
                        await dialog_context.end_active_dialog(
                            DialogReason.CancelCalled
                        )
                    else:
                        dialog_context = (
                            dialog_context.parent if cancel_parents else None
                        )

                    notify = True

                return DialogTurnResult(DialogTurnStatus.Cancelled)

            # Stack was empty and no parent
            return DialogTurnResult(DialogTurnStatus.Empty)
        except Exception as err:
            self.__set_exception_context_data(err)
            raise

    async def find_dialog(self, dialog_id: str) -> Dialog:
        """
        If the dialog cannot be found within the current `DialogSet`, the parent `DialogContext`
        will be searched if there is one.
        :param dialog_id: ID of the dialog to search for.
        :return:
        """
        try:
            dialog = await self.dialogs.find(dialog_id)

            if dialog is None and self.parent is not None:
                dialog = await self.parent.find_dialog(dialog_id)
            return dialog
        except Exception as err:
            self.__set_exception_context_data(err)
            raise

    def find_dialog_sync(self, dialog_id: str) -> Dialog:
        """
        If the dialog cannot be found within the current `DialogSet`, the parent `DialogContext`
        will be searched if there is one.
        :param dialog_id: ID of the dialog to search for.
        :return:
        """
        dialog = self.dialogs.find_dialog(dialog_id)

        if dialog is None and self.parent is not None:
            dialog = self.parent.find_dialog_sync(dialog_id)
        return dialog

    async def replace_dialog(
        self, dialog_id: str, options: object = None
    ) -> DialogTurnResult:
        """
        Ends the active dialog and starts a new dialog in its place. This is particularly useful
        for creating loops or redirecting to another dialog.
        :param dialog_id: ID of the dialog to search for.
        :param options: (Optional) additional argument(s) to pass to the new dialog.
        :return:
        """
        try:
            # End the current dialog and giving the reason.
            await self.end_active_dialog(DialogReason.ReplaceCalled)

            # Start replacement dialog
            return await self.begin_dialog(dialog_id, options)
        except Exception as err:
            self.__set_exception_context_data(err)
            raise

    async def reprompt_dialog(self):
        """
        Calls reprompt on the currently active dialog, if there is one. Used with Prompts that have a reprompt behavior.
        :return:
        """
        try:
            # Check for a dialog on the stack
            if self.active_dialog is not None:
                # Look up dialog
                dialog = await self.find_dialog(self.active_dialog.id)
                if not dialog:
                    raise Exception(
                        "DialogSet.reprompt_dialog(): Can't find A dialog with an id of '%s'."
                        % self.active_dialog.id
                    )

                # Ask dialog to re-prompt if supported
                await dialog.reprompt_dialog(self.context, self.active_dialog)
        except Exception as err:
            self.__set_exception_context_data(err)
            raise

    async def end_active_dialog(self, reason: DialogReason):
        instance = self.active_dialog
        if instance is not None:
            # Look up dialog
            dialog = await self.find_dialog(instance.id)
            if dialog is not None:
                # Notify dialog of end
                await dialog.end_dialog(self.context, instance, reason)

            # Pop dialog off stack
            self._stack.pop(0)

    async def emit_event(
        self,
        name: str,
        value: object = None,
        bubble: bool = True,
        from_leaf: bool = False,
    ) -> bool:
        """
        Searches for a dialog with a given ID.
        Emits a named event for the current dialog, or someone who started it, to handle.
        :param name: Name of the event to raise.
        :param value: Value to send along with the event.
        :param bubble: Flag to control whether the event should be bubbled to its parent if not handled locally.
        Defaults to a value of `True`.
        :param from_leaf: Whether the event is emitted from a leaf node.
        :param cancellationToken: The cancellation token.
        :return: True if the event was handled.
        """
        try:
            # Initialize event
            dialog_event = DialogEvent(
                bubble=bubble,
                name=name,
                value=value,
            )

            dialog_context = self

            # Find starting dialog
            if from_leaf:
                while True:
                    child_dc = dialog_context.child

                    if child_dc:
                        dialog_context = child_dc
                    else:
                        break

            # Dispatch to active dialog first
            instance = dialog_context.active_dialog

            if instance:
                dialog = await dialog_context.find_dialog(instance.id)

                if dialog:
                    return await dialog.on_dialog_event(dialog_context, dialog_event)

            return False
        except Exception as err:
            self.__set_exception_context_data(err)
            raise

    def __set_exception_context_data(self, exception: Exception):
        if not hasattr(exception, "data"):
            exception.data = {}

        if not type(self).__name__ in exception.data:
            stack = []
            current_dc = self

            while current_dc is not None:
                stack = stack + [x.id for x in current_dc.stack]
                current_dc = current_dc.parent

            exception.data[type(self).__name__] = {
                "active_dialog": (
                    None if self.active_dialog is None else self.active_dialog.id
                ),
                "parent": None if self.parent is None else self.parent.active_dialog.id,
                "stack": self.stack,
            }