# Orca
#
# Copyright 2005-2008 Sun Microsystems Inc.
# Copyright 2016-2023 Igalia, S.L.
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the
# Free Software Foundation, Inc., Franklin Street, Fifth Floor,
# Boston MA  02110-1301 USA.

# pylint: disable=too-many-lines
# pylint: disable=too-many-public-methods
# pylint: disable=too-many-instance-attributes

"""Module for flat-review commands"""

from __future__ import annotations

import time
from enum import Enum
from typing import TYPE_CHECKING

import gi

gi.require_version("Atspi", "2.0")
gi.require_version("Gtk", "3.0")
from gi.repository import Atspi, GLib, Gtk  # pylint: disable=no-name-in-module

from . import (
    braille,
    braille_presenter,
    clipboard,
    dbus_service,
    debug,
    flat_review,
    flat_review_presenter_command_definitions,
    focus_manager,
    gsettings_registry,
    guilabels,
    input_event,
    input_event_manager,
    messages,
    presentation_manager,
    script_manager,
    speech_presenter,
)
from .ax_event_synthesizer import AXEventSynthesizer
from .ax_object import AXObject
from .ax_text import AXText
from .ax_utilities import AXUtilities
from .ax_utilities_event import TextEventReason
from .ax_utilities_text import CaretSetReason
from .extension import Extension

if TYPE_CHECKING:
    from .command import Command
    from .dbus_service import UInt32
    from .flat_review_presenter_preferences_grid import FlatReviewPreferencesGrid
    from .scripts import default


@gsettings_registry.get_registry().gsettings_enum(
    "org.gnome.Orca.FocusTracking",
    values={"off": 0, "auto": 1, "on": 2},
)
class FocusTracking(Enum):
    """How closely flat review follows the focus/caret location."""

    OFF = 0
    AUTO = 1
    ON = 2


@gsettings_registry.get_registry().gsettings_schema("org.gnome.Orca.FlatReview", name="flat-review")
class FlatReviewPresenter(Extension):
    """Provides access to on-screen objects via flat-review."""

    _SCHEMA = "flat-review"
    KEY_DISPLAY_UPDATES = "display-updates"
    KEY_FOCUS_TRACKING = "focus-tracking"
    KEY_RESTRICTED = "restricted"
    KEY_SPEAK_UPDATES = "speak-updates"

    def _get_setting(self, key: str, default: bool) -> bool:
        """Returns the dconf value for key, or default if not in dconf."""

        return gsettings_registry.get_registry().layered_lookup(
            self._SCHEMA,
            key,
            "b",
            default=default,
        )

    GROUP_LABEL = guilabels.KB_GROUP_FLAT_REVIEW

    _EVENT_TYPES: tuple[str, ...] = ("object:text-changed:insert", "object:text-caret-moved")

    def __init__(self) -> None:
        self._context: flat_review.Context | None = None
        self._current_contents: str = ""
        self._last_presented_unit: int = flat_review.Context.LINE
        self._last_input_event: input_event.InputEvent | None = None
        self._context_input_event: input_event.InputEvent | None = None
        self._restrict: bool = self.get_is_restricted()
        self._gui: FlatReviewContextGUI | None = None
        self._event_listener: Atspi.EventListener = Atspi.EventListener.new(self._listener)
        self._registered_app: Atspi.Accessible | None = None
        self._context_invalidated: bool = False
        self._location_invalidated: bool = False
        self._pending_caret_moved: Atspi.Event | None = None
        self._pending_text_inserted: Atspi.Event | None = None
        self._idle_id: int = 0
        self._region_changed_listener_registered: bool = False
        super().__init__()

    def _listener(self, event: Atspi.Event) -> None:
        """Generic event listener."""

        # TODO - JD: Implement support to invalidate individual objects.
        if self._context is None:
            return

        if event.source != self._context.get_current_object():
            return

        if event.type == "object:text-changed:insert":
            self._pending_text_inserted = event
        elif event.type == "object:text-caret-moved":
            self._pending_caret_moved = event

        if self._idle_id == 0:
            self._idle_id = GLib.idle_add(self._process_pending_events)

    def _change_invalidates_location(
        self, text_inserted: Atspi.Event | None, caret_moved: Atspi.Event | None
    ) -> bool:
        """Returns True if a change to the reviewed object should move the review location."""

        tracking = self.get_focus_tracking()
        if tracking == FocusTracking.OFF.value:
            return False
        if tracking == FocusTracking.ON.value:
            # Always follow a caret move; ignore unpresentable insertions.
            if caret_moved is not None:
                return True
            return (
                text_inserted is not None
                and AXUtilities.get_text_event_reason(text_inserted)
                != TextEventReason.AUTO_INSERTION_UNPRESENTABLE
            )

        if text_inserted is not None and AXUtilities.get_text_event_reason(text_inserted) in (
            TextEventReason.TYPING,
            TextEventReason.AUTO_INSERTION_PRESENTABLE,
        ):
            return True
        return caret_moved is not None and AXUtilities.get_text_event_reason(caret_moved) in (
            TextEventReason.NAVIGATION_BY_LINE,
            TextEventReason.NAVIGATION_TO_FILE_BOUNDARY,
        )

    def _process_pending_events(self) -> bool:
        """Processes pending events. Returns False so GLib doesn't reschedule."""

        self._idle_id = 0
        caret_moved = self._pending_caret_moved
        text_inserted = self._pending_text_inserted
        self._pending_caret_moved = None
        self._pending_text_inserted = None

        if self._context is None:
            return False

        current_obj = self._context.get_current_object()
        if caret_moved is not None and caret_moved.source != current_obj:
            caret_moved = None
        if text_inserted is not None and text_inserted.source != current_obj:
            text_inserted = None

        if caret_moved is None and text_inserted is None:
            return False

        self._context_invalidated = True
        if self._change_invalidates_location(text_inserted, caret_moved):
            self._location_invalidated = True

        if not self.last_input_event_was_review_command():
            msg = (
                "FLAT REVIEW PRESENTER: Not refreshing braille; "
                "last input event was not a review command."
            )
            debug.print_message(debug.LEVEL_INFO, msg, True)
            return False

        script = script_manager.get_manager().get_active_script()
        if script is not None:
            self._present_review_update(script)

        return False

    def _register_event_listeners(self, app: Atspi.Accessible) -> None:
        """Registers the event listeners for app, replacing any previous registration."""

        if app == self._registered_app:
            return
        if self._registered_app is not None:
            self._deregister_event_listeners()
        for event_type in self._EVENT_TYPES:
            self._event_listener.register_with_app(event_type, app=app)
        self._registered_app = app

    def _deregister_event_listeners(self) -> None:
        """Deregisters the event listeners if currently registered."""

        if self._registered_app is None:
            return

        try:
            for event_type in self._EVENT_TYPES:
                self._event_listener.deregister(event_type)
        except GLib.GError as error:
            msg = f"FLAT REVIEW PRESENTER: Exception deregistering {event_type}: {error}"
            debug.print_message(debug.LEVEL_INFO, msg, True)

        self._registered_app = None

    def _get_commands(self) -> list[Command]:
        return flat_review_presenter_command_definitions.get_commands(self)

    def is_active(self) -> bool:
        """Returns True if the flat review presenter is active."""

        mode, _obj = focus_manager.get_manager().get_active_mode_and_object_of_interest()
        return mode == focus_manager.FLAT_REVIEW

    def last_input_event_was_review_command(self) -> bool:
        """Returns True if the last input event was a flat review command."""

        if self._last_input_event is None:
            return False

        manager = input_event_manager.get_manager()
        result = manager.previous_event_equals_or_is_release_for_event(self._last_input_event)
        string = self._last_input_event.as_single_line_string()

        msg = f"FLAT REVIEW PRESENTER: Last review event ({string}) is last input event: {result}"
        debug.print_message(debug.LEVEL_INFO, msg, True)
        return result

    def _can_use_existing_context(  # pylint: disable=too-many-return-statements
        self, is_panning: bool = False
    ) -> bool:
        """Returns True if the existing context can be used."""

        if not self._context:
            return False

        if self._context_invalidated:
            msg = "FLAT REVIEW PRESENTER: Context invalidated by an accessible event."
            debug.print_message(debug.LEVEL_INFO, msg, True)
            return False

        last_input_event = input_event_manager.get_manager().get_last_input_event()
        if last_input_event is not None and last_input_event is self._context_input_event:
            msg = "FLAT REVIEW PRESENTER: No new input event since context was last validated."
            debug.print_message(debug.LEVEL_INFO, msg, True)
            return True

        if self._context.is_stale():
            msg = "FLAT REVIEW PRESENTER: Context is stale."
            debug.print_message(debug.LEVEL_INFO, msg, True)
            return False

        if self._last_input_event is None:
            return True

        if is_panning:
            return True

        # TODO - JD: Add some additional logic for cases where we know that the previous input
        # event should not invalidate the context. For instance, the system information presenter
        # and where am I presenter will never trigger scrolling, text changes, etc.

        return self.last_input_event_was_review_command()

    # pylint: disable-next=too-many-locals
    def get_or_create_context(
        self, script: default.Script | None = None, is_panning: bool = False
    ) -> flat_review.Context:
        """Returns the flat review context, creating one if necessary."""

        if not self._can_use_existing_context(is_panning):
            msg = f"FLAT REVIEW PRESENTER: Creating new context. Restrict: {self._restrict}"
            debug.print_message(debug.LEVEL_INFO, msg, True)

            previous_obj, previous_location = None, None
            if self._context is not None and not self._location_invalidated:
                previous_obj = self._context.get_current_object()
                previous_location = self._context.get_current_location()

            manager = focus_manager.get_manager()
            if self._restrict:
                mode, obj = manager.get_active_mode_and_object_of_interest()
                self._context = flat_review.Context(script, root=obj)
            else:
                self._context = flat_review.Context(script)

            # The new context is built at the focus, so move it back onto the reviewed object.
            if (
                not self._restrict
                and previous_obj is not None
                and self.get_focus_tracking() == FocusTracking.OFF.value
            ):
                self._context.set_current_to_zone_with_object(previous_obj)

            current_obj = self._context.get_current_object()
            if previous_obj == current_obj and previous_location is not None:
                line, zone, word, char = previous_location
                # Try the exact location first; if the new context's structure has
                # shifted (e.g. a word got shorter), fall back progressively so we
                # still land on the right line.
                for fallback in (
                    (line, zone, word, char),
                    (line, zone, word, 0),
                    (line, zone, 0, 0),
                    (line, 0, 0, 0),
                ):
                    if self._context.can_set_location(fallback):
                        tokens = [
                            "FLAT REVIEW PRESENTER: Restoring previous location in new context:",
                            current_obj,
                            fallback,
                        ]
                        debug.print_tokens(debug.LEVEL_INFO, tokens, True)
                        self._context.set_current_location(fallback)
                        break

            manager.emit_region_changed(current_obj, mode=focus_manager.FLAT_REVIEW)
            self._context_input_event = input_event_manager.get_manager().get_last_input_event()
            app = AXUtilities.get_application(current_obj)
            if app is not None:
                self._register_event_listeners(app)
            self._context_invalidated = False
            self._location_invalidated = False
            self._sync_region_changed_listener()
            return self._context

        assert self._context is not None
        msg = f"FLAT REVIEW PRESENTER: Using existing context. Restrict: {self._restrict}"
        debug.print_message(debug.LEVEL_INFO, msg, True)

        # If we are in unrestricted mode, update the context as below.
        # If the context already exists, but the active mode is not flat review, update
        # the flat review location to that of the object of interest -- if the object of
        # interest is in the flat review context (which means it's on screen). In some
        # cases the object of interest will not be in the flat review context because it
        # is represented by descendant text objects. set_current_to_zone_with_object checks
        # for this condition and if it can find a zone whose ancestor is the object of
        # interest, it will set the current zone to the descendant, causing Orca to
        # present the text at the location of the object of interest.
        mode, obj = focus_manager.get_manager().get_active_mode_and_object_of_interest()
        obj = obj or focus_manager.get_manager().get_locus_of_focus()
        # On invalidates the context elsewhere; off stays put; only auto moves the location here.
        if (
            self.get_focus_tracking() == FocusTracking.AUTO.value
            and mode != focus_manager.FLAT_REVIEW
            and obj != self._context.get_current_object()
            and not self._restrict
        ):
            tokens = [
                "FLAT REVIEW PRESENTER: Attempting to update location from",
                self._context.get_current_object(),
                "to",
                obj,
            ]
            debug.print_tokens(debug.LEVEL_INFO, tokens, True)
            self._context.set_current_to_zone_with_object(obj)

        # If we are restricting, and the current mode is not flat review, calculate a new context
        if self._restrict and mode != focus_manager.FLAT_REVIEW:
            msg = "FLAT REVIEW PRESENTER: Creating new restricted context."
            debug.print_message(debug.LEVEL_INFO, msg, True)
            self._context = flat_review.Context(script, obj)

        self._context_input_event = input_event_manager.get_manager().get_last_input_event()
        return self._context

    def start(
        self,
        script: default.Script | None = None,
        event: input_event.InputEvent | None = None,
    ) -> None:
        """Starts flat review."""

        if self.is_active():
            msg = "FLAT REVIEW PRESENTER: Already in flat review"
            debug.print_message(debug.LEVEL_INFO, msg, True)
            return

        msg = "FLAT REVIEW PRESENTER: Starting flat review"
        debug.print_message(debug.LEVEL_INFO, msg, True)

        if script is None:
            script = script_manager.get_manager().get_active_script()
            assert script is not None

        context = self.get_or_create_context(script)
        manager = focus_manager.get_manager()
        if manager.get_active_mode_and_object_of_interest()[0] != focus_manager.FLAT_REVIEW:
            manager.emit_region_changed(
                context.get_current_object(), mode=focus_manager.FLAT_REVIEW
            )
        if event is None:
            return

        if speech_presenter.get_presenter().use_verbose_speech():
            presentation_manager.get_manager().present_message(messages.FLAT_REVIEW_START)
        self._item_presentation(script, event)

    def quit(
        self,
        script: default.Script | None = None,
        event: input_event.InputEvent | None = None,
    ) -> None:
        """Quits flat review."""

        if self._context is None:
            msg = "FLAT REVIEW PRESENTER: Not in flat review"
            debug.print_message(debug.LEVEL_INFO, msg, True)
            return

        msg = "FLAT REVIEW PRESENTER: Quitting flat review"
        debug.print_message(debug.LEVEL_INFO, msg, True)

        self._last_input_event = None
        self._context = None
        self._context_input_event = None
        self._deregister_event_listeners()
        self._sync_region_changed_listener()
        self._context_invalidated = False
        self._location_invalidated = False
        if self._idle_id:
            GLib.source_remove(self._idle_id)
            self._idle_id = 0
        self._pending_caret_moved = None
        self._pending_text_inserted = None
        focus = focus_manager.get_manager().get_locus_of_focus()
        focus_manager.get_manager().emit_region_changed(focus, mode=focus_manager.FOCUS_TRACKING)
        if event is None or script is None:
            return

        if speech_presenter.get_presenter().use_verbose_speech():
            presentation_manager.get_manager().present_message(messages.FLAT_REVIEW_STOP)
        script.update_braille(focus)

    def _sync_region_changed_listener(self) -> None:
        """Listens for focus changes only while a review context exists."""

        needed = self._context is not None
        manager = focus_manager.get_manager()
        if needed and not self._region_changed_listener_registered:
            manager.add_region_changed_listener(self._on_region_changed)
            self._region_changed_listener_registered = True
        elif not needed and self._region_changed_listener_registered:
            manager.remove_region_changed_listener(self._on_region_changed)
            self._region_changed_listener_registered = False

    def _on_region_changed(self, _obj: Atspi.Accessible | None, mode: str) -> None:
        """Resets the review state when focus leaves flat review and tracking is on."""

        if mode == focus_manager.FLAT_REVIEW:
            return
        if self.get_focus_tracking() != FocusTracking.ON.value:
            return

        msg = "FLAT REVIEW PRESENTER: Focus left flat review; resetting context."
        debug.print_message(debug.LEVEL_INFO, msg, True)
        self._context_invalidated = True
        self._location_invalidated = True
        self._last_input_event = None

    @dbus_service.command
    def toggle_flat_review_mode(
        self,
        script: default.Script | None = None,
        event: input_event.InputEvent | None = None,
        notify_user: bool = False,
    ) -> bool:
        """Toggles between flat review mode and focus tracking mode."""

        tokens = [
            "FLAT REVIEW PRESENTER: toggle_flat_review_mode. Script:",
            script,
            "Event:",
            event,
            "notify_user:",
            notify_user,
        ]
        debug.print_tokens(debug.LEVEL_INFO, tokens, True)

        if self.is_active():
            self.quit(script, event)
            return True

        self.start(script, event)
        self._last_input_event = event
        return True

    @dbus_service.command
    def go_home(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        notify_user: bool = True,  # pylint: disable=unused-argument
    ) -> bool:
        """Moves to the top left of the current window."""

        tokens = [
            "FLAT REVIEW PRESENTER: go_home. Script:",
            script,
            "Event:",
            event,
            "notify_user:",
            notify_user,
        ]
        debug.print_tokens(debug.LEVEL_INFO, tokens, True)

        self._context = self.get_or_create_context(script)
        self._context.go_to_start_of(flat_review.Context.WINDOW)
        self.present_line(script, event)
        self._last_input_event = event
        return True

    @dbus_service.command
    def go_end(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        notify_user: bool = True,
    ) -> bool:
        """Moves to the bottom right of the current window."""

        tokens = [
            "FLAT REVIEW PRESENTER: go_end. Script:",
            script,
            "Event:",
            event,
            "notify_user:",
            notify_user,
        ]
        debug.print_tokens(debug.LEVEL_INFO, tokens, True)

        self._context = self.get_or_create_context(script)
        self._context.go_to_end_of(flat_review.Context.WINDOW)
        self.present_line(script, event)
        self._last_input_event = event
        return True

    @dbus_service.command
    def go_bottom_left(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        notify_user: bool = True,
    ) -> bool:
        """Moves to the bottom left of the current window."""

        tokens = [
            "FLAT REVIEW PRESENTER: go_bottom_left. Script:",
            script,
            "Event:",
            event,
            "notify_user:",
            notify_user,
        ]
        debug.print_tokens(debug.LEVEL_INFO, tokens, True)

        self._context = self.get_or_create_context(script)
        self._context.go_to_end_of(flat_review.Context.WINDOW)
        self._context.go_to_start_of(flat_review.Context.LINE)
        self.present_line(script, event)
        self._last_input_event = event
        return True

    @dbus_service.command
    def go_previous_line(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        notify_user: bool = True,
    ) -> bool:
        """Moves to the previous line."""

        tokens = [
            "FLAT REVIEW PRESENTER: go_previous_line. Script:",
            script,
            "Event:",
            event,
            "notify_user:",
            notify_user,
        ]
        debug.print_tokens(debug.LEVEL_INFO, tokens, True)

        self._context = self.get_or_create_context(script)
        if self._context.go_previous_line():
            self.present_line(script, event)
        self._last_input_event = event
        return True

    @dbus_service.command
    def present_line(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        notify_user: bool = True,
    ) -> bool:
        """Presents the current line."""

        tokens = [
            "FLAT REVIEW PRESENTER: present_line. Script:",
            script,
            "Event:",
            event,
            "notify_user:",
            notify_user,
        ]
        debug.print_tokens(debug.LEVEL_INFO, tokens, True)

        self._line_presentation(script, event, 1)
        self._last_input_event = event
        return True

    @dbus_service.command
    def go_next_line(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        notify_user: bool = True,
    ) -> bool:
        """Moves to the next line."""

        tokens = [
            "FLAT REVIEW PRESENTER: go_next_line. Script:",
            script,
            "Event:",
            event,
            "notify_user:",
            notify_user,
        ]
        debug.print_tokens(debug.LEVEL_INFO, tokens, True)

        self._context = self.get_or_create_context(script)
        if self._context.go_next_line():
            self.present_line(script, event)
        self._last_input_event = event
        return True

    @dbus_service.command
    def spell_line(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        notify_user: bool = True,
    ) -> bool:
        """Presents the current line letter by letter."""

        tokens = [
            "FLAT REVIEW PRESENTER: spell_line. Script:",
            script,
            "Event:",
            event,
            "notify_user:",
            notify_user,
        ]
        debug.print_tokens(debug.LEVEL_INFO, tokens, True)

        self._line_presentation(script, event, 2)
        self._last_input_event = event
        return True

    @dbus_service.command
    def phonetic_line(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        notify_user: bool = True,
    ) -> bool:
        """Presents the current line letter by letter phonetically."""

        tokens = [
            "FLAT REVIEW PRESENTER: phonetic_line. Script:",
            script,
            "Event:",
            event,
            "notify_user:",
            notify_user,
        ]
        debug.print_tokens(debug.LEVEL_INFO, tokens, True)

        self._line_presentation(script, event, 3)
        self._last_input_event = event
        return True

    @dbus_service.command
    def go_start_of_line(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        notify_user: bool = True,
    ) -> bool:
        """Moves to the beginning of the current line."""

        tokens = [
            "FLAT REVIEW PRESENTER: go_start_of_line. Script:",
            script,
            "Event:",
            event,
            "notify_user:",
            notify_user,
        ]
        debug.print_tokens(debug.LEVEL_INFO, tokens, True)

        self._context = self.get_or_create_context(script)
        self._context.go_to_start_of(flat_review.Context.LINE)
        self.present_character(script, event)
        self._last_input_event = event
        return True

    @dbus_service.command
    def go_end_of_line(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        notify_user: bool = True,
    ) -> bool:
        """Moves to the end of the line."""

        tokens = [
            "FLAT REVIEW PRESENTER: go_end_of_line. Script:",
            script,
            "Event:",
            event,
            "notify_user:",
            notify_user,
        ]
        debug.print_tokens(debug.LEVEL_INFO, tokens, True)

        self._context = self.get_or_create_context(script)
        self._context.go_to_end_of(flat_review.Context.LINE)
        self.present_character(script, event)
        self._last_input_event = event
        return True

    @dbus_service.command
    def go_previous_item(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        notify_user: bool = True,
    ) -> bool:
        """Moves to the previous item or word."""

        tokens = [
            "FLAT REVIEW PRESENTER: go_previous_item. Script:",
            script,
            "Event:",
            event,
            "notify_user:",
            notify_user,
        ]
        debug.print_tokens(debug.LEVEL_INFO, tokens, True)

        self._context = self.get_or_create_context(script)
        if self._context.go_previous_word():
            self.present_item(script, event)
        self._last_input_event = event
        return True

    @dbus_service.command
    def present_item(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        notify_user: bool = True,
    ) -> bool:
        """Presents the current item/word."""

        tokens = [
            "FLAT REVIEW PRESENTER: present_item. Script:",
            script,
            "Event:",
            event,
            "notify_user:",
            notify_user,
        ]
        debug.print_tokens(debug.LEVEL_INFO, tokens, True)

        self._item_presentation(script, event, 1)
        self._last_input_event = event
        return True

    @dbus_service.command
    def go_next_item(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        notify_user: bool = True,
    ) -> bool:
        """Moves to the next item or word."""

        tokens = [
            "FLAT REVIEW PRESENTER: go_next_item. Script:",
            script,
            "Event:",
            event,
            "notify_user:",
            notify_user,
        ]
        debug.print_tokens(debug.LEVEL_INFO, tokens, True)

        self._context = self.get_or_create_context(script)
        if self._context.go_next_word():
            self.present_item(script, event)
        self._last_input_event = event
        return True

    @dbus_service.command
    def spell_item(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        notify_user: bool = True,
    ) -> bool:
        """Presents the current item/word letter by letter."""

        tokens = [
            "FLAT REVIEW PRESENTER: spell_item. Script:",
            script,
            "Event:",
            event,
            "notify_user:",
            notify_user,
        ]
        debug.print_tokens(debug.LEVEL_INFO, tokens, True)

        self._item_presentation(script, event, 2)
        self._last_input_event = event
        return True

    @dbus_service.command
    def phonetic_item(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        notify_user: bool = True,
    ) -> bool:
        """Presents the current word letter by letter phonetically."""

        tokens = [
            "FLAT REVIEW PRESENTER: phonetic_item. Script:",
            script,
            "Event:",
            event,
            "notify_user:",
            notify_user,
        ]
        debug.print_tokens(debug.LEVEL_INFO, tokens, True)

        self._item_presentation(script, event, 3)
        self._last_input_event = event
        return True

    @dbus_service.command
    def go_previous_character(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        notify_user: bool = True,
    ) -> bool:
        """Moves to the previous character."""

        tokens = [
            "FLAT REVIEW PRESENTER: go_previous_character. Script:",
            script,
            "Event:",
            event,
            "notify_user:",
            notify_user,
        ]
        debug.print_tokens(debug.LEVEL_INFO, tokens, True)

        self._context = self.get_or_create_context(script)
        if self._context.go_previous_character():
            self.present_character(script, event)
        self._last_input_event = event
        return True

    @dbus_service.command
    def present_character(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        notify_user: bool = True,
    ) -> bool:
        """Presents the current character."""

        tokens = [
            "FLAT REVIEW PRESENTER: present_character. Script:",
            script,
            "Event:",
            event,
            "notify_user:",
            notify_user,
        ]
        debug.print_tokens(debug.LEVEL_INFO, tokens, True)

        self._character_presentation(script, event, 1)
        self._last_input_event = event
        return True

    @dbus_service.command
    def go_next_character(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        notify_user: bool = True,
    ) -> bool:
        """Moves to the next character."""

        tokens = [
            "FLAT REVIEW PRESENTER: go_next_character. Script:",
            script,
            "Event:",
            event,
            "notify_user:",
            notify_user,
        ]
        debug.print_tokens(debug.LEVEL_INFO, tokens, True)

        self._context = self.get_or_create_context(script)
        if self._context.go_next_character():
            self.present_character(script, event)
        self._last_input_event = event
        return True

    @dbus_service.command
    def spell_character(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        notify_user: bool = True,
    ) -> bool:
        """Presents the current character phonetically."""

        tokens = [
            "FLAT REVIEW PRESENTER: spell_character. Script:",
            script,
            "Event:",
            event,
            "notify_user:",
            notify_user,
        ]
        debug.print_tokens(debug.LEVEL_INFO, tokens, True)

        self._character_presentation(script, event, 2)
        self._last_input_event = event
        return True

    @dbus_service.command
    def unicode_current_character(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        notify_user: bool = True,
    ) -> bool:
        """Presents the current character's unicode value."""

        tokens = [
            "FLAT REVIEW PRESENTER: unicode_current_character. Script:",
            script,
            "Event:",
            event,
            "notify_user:",
            notify_user,
        ]
        debug.print_tokens(debug.LEVEL_INFO, tokens, True)

        self._character_presentation(script, event, 3)
        self._last_input_event = event
        return True

    @dbus_service.command
    def go_above(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        notify_user: bool = True,
    ) -> bool:
        """Moves to the character above."""

        tokens = [
            "FLAT REVIEW PRESENTER: go_above. Script:",
            script,
            "Event:",
            event,
            "notify_user:",
            notify_user,
        ]
        debug.print_tokens(debug.LEVEL_INFO, tokens, True)

        self._context = self.get_or_create_context(script)
        if self._context.go_up():
            self.present_item(script, event)
        self._last_input_event = event
        return True

    @dbus_service.command
    def go_below(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        notify_user: bool = True,
    ) -> bool:
        """Moves to the character below."""

        tokens = [
            "FLAT REVIEW PRESENTER: go_below. Script:",
            script,
            "Event:",
            event,
            "notify_user:",
            notify_user,
        ]
        debug.print_tokens(debug.LEVEL_INFO, tokens, True)

        self._context = self.get_or_create_context(script)
        if self._context.go_down():
            self.present_item(script, event)
        self._last_input_event = event
        return True

    def get_current_object(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        notify_user: bool = True,
    ) -> Atspi.Accessible:
        """Returns the current accessible object."""

        tokens = [
            "FLAT REVIEW PRESENTER: get_current_object. Script:",
            script,
            "Event:",
            event,
            "notify_user:",
            notify_user,
        ]
        debug.print_tokens(debug.LEVEL_INFO, tokens, True)

        self._context = self.get_or_create_context(script)
        self._last_input_event = event
        return self._context.get_current_object()

    @dbus_service.command
    def move_review_to_focus(  # pylint: disable=unused-argument
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        notify_user: bool = True,
    ) -> bool:
        """Moves the flat review location to the object with focus."""

        tokens = ["FLAT REVIEW PRESENTER: move_review_to_focus. Script:", script, "Event:", event]
        debug.print_tokens(debug.LEVEL_INFO, tokens, True)

        self._last_input_event = event
        context = self.get_or_create_context(script)
        obj = focus_manager.get_manager().get_locus_of_focus()
        if not context.set_current_to_zone_with_object(obj):
            self._context = None
            self.get_or_create_context(script)
        return self._item_presentation(script, event)

    @dbus_service.command
    def move_focus_to_review(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        notify_user: bool = True,
    ) -> bool:
        """Attempts to move focus to the object at the flat review location."""

        tokens = ["FLAT REVIEW PRESENTER: move_focus_to_review. Script:", script, "Event:", event]
        debug.print_tokens(debug.LEVEL_INFO, tokens, True)

        self._context = self.get_or_create_context(script)
        self._last_input_event = event
        obj = self._context.get_current_object()

        # If focus is already on the reviewed object, no focus event will present the change,
        # so capture how far the review location is from the caret to announce the move.
        focus_stays = obj == focus_manager.get_manager().get_locus_of_focus()
        old_location = target_location = self._context.get_current_location()
        if focus_stays:
            self._context.set_current_to_zone_with_object(obj)
            old_location = self._context.get_current_location()
            self._context.set_current_location(target_location)

        AXObject.grab_focus(obj)
        offset = self._context.get_current_text_offset()
        caret_moved = False
        if offset >= 0:
            AXUtilities.set_caret_offset_with_reason(obj, offset, CaretSetReason.FLAT_REVIEW)
            caret_moved = AXText.get_caret_offset(obj) == offset

        if AXUtilities.is_focusable(obj):
            if focus_stays and not caret_moved:
                if notify_user:
                    presentation_manager.get_manager().present_message(
                        messages.FLAT_REVIEW_LOCATION_UNCHANGED
                    )
            elif focus_stays:
                if old_location[0] != target_location[0]:
                    self._line_presentation(script, event)
                elif old_location[1:3] != target_location[1:3]:
                    self._item_presentation(script, event)
                else:
                    self._character_presentation(script, event)
            return True
        if script.utilities.in_document_content(obj):
            focus_manager.get_manager().set_locus_of_focus(None, obj)
        elif notify_user:
            presentation_manager.get_manager().present_message(
                messages.FLAT_REVIEW_LOCATION_UNCHANGED
            )
        return True

    @dbus_service.command
    def present_object(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        notify_user: bool = True,
    ) -> bool:
        """Presents the current accessible object."""

        tokens = [
            "FLAT REVIEW PRESENTER: present_object. Script:",
            script,
            "Event:",
            event,
            "notify_user:",
            notify_user,
        ]
        debug.print_tokens(debug.LEVEL_INFO, tokens, True)

        self._context = self.get_or_create_context(script)
        if not isinstance(event, input_event.BrailleEvent):
            script.present_object(self._context.get_current_object(), generate_braille=False)

        focus_manager.get_manager().emit_region_changed(
            self._context.get_current_object(),
            mode=focus_manager.FLAT_REVIEW,
        )
        self._last_input_event = event
        return True

    @dbus_service.command
    def left_click_on_object(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        notify_user: bool = True,
    ) -> bool:
        """Attempts to synthesize a left click on the current accessible."""

        tokens = [
            "FLAT REVIEW PRESENTER: left_click_on_object. Script:",
            script,
            "Event:",
            event,
            "notify_user:",
            notify_user,
        ]
        debug.print_tokens(debug.LEVEL_INFO, tokens, True)

        self._context = self.get_or_create_context(script)
        self._last_input_event = event
        obj = self._context.get_current_object()
        offset = self._context.get_current_text_offset()
        if offset >= 0 and AXEventSynthesizer.click_character(obj, offset, 1):
            return True
        return AXEventSynthesizer.click_object(obj, 1)

    @dbus_service.command
    def right_click_on_object(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        notify_user: bool = True,
    ) -> bool:
        """Attempts to synthesize a right click on the current accessible."""

        tokens = [
            "FLAT REVIEW PRESENTER: right_click_on_object. Script:",
            script,
            "Event:",
            event,
            "notify_user:",
            notify_user,
        ]
        debug.print_tokens(debug.LEVEL_INFO, tokens, True)

        self._context = self.get_or_create_context(script)
        self._last_input_event = event
        obj = self._context.get_current_object()
        offset = self._context.get_current_text_offset()
        if offset >= 0 and AXEventSynthesizer.click_character(obj, offset, 3):
            return True
        return AXEventSynthesizer.click_object(obj, 3)

    @dbus_service.command
    def route_pointer_to_object(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        notify_user: bool = True,
    ) -> bool:
        """Routes the mouse pointer to the current accessible."""

        tokens = [
            "FLAT REVIEW PRESENTER: route_pointer_to_object. Script:",
            script,
            "Event:",
            event,
            "notify_user:",
            notify_user,
        ]
        debug.print_tokens(debug.LEVEL_INFO, tokens, True)

        self._context = self.get_or_create_context(script)
        self._last_input_event = event
        obj = self._context.get_current_object()
        offset = self._context.get_current_text_offset()
        if offset >= 0 and AXEventSynthesizer.route_to_character(obj, offset):
            return True
        return AXEventSynthesizer.route_to_object(obj)

    def _update_braille(self, script: default.Script) -> None:
        """Obtains the braille regions for the current flat review line and displays them."""

        if not braille_presenter.get_presenter().use_braille():
            return

        self._context = self.get_or_create_context(script)
        regions, focused_region = self._context.get_current_braille_regions()
        if not regions:
            braille_presenter.get_presenter().refresh_braille()
            return

        braille_presenter.get_presenter().present_regions(
            list(regions),
            focused_region,
        )

    def _speak_review_unit(self, string: str) -> None:
        """Speaks string as the current review unit (used for live updates)."""

        presenter = presentation_manager.get_manager()
        if not string or string == "\n":
            presenter.speak_message(messages.BLANK)
        elif string.isspace():
            presenter.speak_message(messages.WHITE_SPACE)
        else:
            obj = self._context.get_current_object() if self._context else None
            presenter.speak_accessible_text(obj, string)

    def _present_review_update(self, script: default.Script) -> None:
        """Presents the current review unit when it changes via a live update."""

        self._context = self.get_or_create_context(script)
        if self.get_displays_updates():
            self._update_braille(script)

        if not self.get_speaks_updates():
            return

        if self._last_presented_unit == flat_review.Context.WORD:
            current = self._context.get_current_word_string()
        elif self._last_presented_unit == flat_review.Context.CHAR:
            current = self._context.get_current_character_string()
        else:
            current = self._context.get_current_line_string()

        if current == self._current_contents:
            return

        self._speak_review_unit(current)
        self._current_contents = current

    def pan_braille_left(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
    ) -> bool:
        """Pans the braille display left."""

        self._context = self.get_or_create_context(script, is_panning=True)
        self._last_input_event = event

        # Try to pan left. If we couldn't (at edge), move to previous line.
        if not braille_presenter.get_presenter().pan_left():
            self._context.go_to_start_of(flat_review.Context.LINE)
            self._context.go_previous_character()
            self._update_braille(script)
            return True

        # After panning, find a region that has a zone attribute to sync flat review context.
        # We do cell-by-cell panning here because not all braille regions have zones (e.g.,
        # buttons don't have zones, only text regions do). This finds the first region with
        # a zone so we can update the flat review position accordingly.
        region_info = braille.get_region_at_cell(1)
        braille_region = region_info.region
        offset_in_zone = region_info.offset_in_region
        while braille_region and not hasattr(braille_region, "zone"):
            # Cell-by-cell panning (amount=1) to find the first region with a zone attribute.
            if not braille.pan_left(1):
                break
            region_info = braille.get_region_at_cell(1)
            braille_region = region_info.region
            offset_in_zone = region_info.offset_in_region

        if braille_region and not hasattr(braille_region, "zone"):
            self._context.go_to_start_of(flat_review.Context.LINE)
            self._context.go_previous_character()
            self._update_braille(script)
        elif braille_region and hasattr(braille_region, "zone"):
            self._context.set_current_zone(braille_region.zone, offset_in_zone)
            braille_presenter.get_presenter().refresh_braille(pan_to_cursor=False)

        return True

    def pan_braille_right(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
    ) -> bool:
        """Pans the braille display right."""

        self._context = self.get_or_create_context(script, is_panning=True)
        self._last_input_event = event

        # Try to pan right. If we couldn't (at edge), move to next line.
        if not braille_presenter.get_presenter().pan_right():
            self._context.go_next_line()
            self._update_braille(script)
            return True

        # After panning, find a region that has a zone attribute to sync flat review context.
        # We do cell-by-cell panning here because not all braille regions have zones (e.g.,
        # buttons don't have zones, only text regions do). This finds the first region with
        # a zone so we can update the flat review position accordingly.
        region_info = braille.get_region_at_cell(1)
        braille_region = region_info.region
        offset_in_zone = region_info.offset_in_region
        while braille_region and not hasattr(braille_region, "zone"):
            # Cell-by-cell panning (amount=1) to find the first region with a zone attribute.
            if not braille.pan_right(1):
                break
            region_info = braille.get_region_at_cell(1)
            braille_region = region_info.region
            offset_in_zone = region_info.offset_in_region

        if braille_region and not hasattr(braille_region, "zone"):
            self._context.go_next_line()
            self._update_braille(script)
        elif braille_region and hasattr(braille_region, "zone"):
            self._context.set_current_zone(braille_region.zone, offset_in_zone)
            braille_presenter.get_presenter().refresh_braille(pan_to_cursor=False)

        return True

    def _get_all_lines(
        self,
        script: default.Script,
        _event: input_event.InputEvent | None = None,
    ) -> tuple[list[tuple[str, Atspi.Accessible | None]], tuple[int, int, int, int]]:
        """Returns a (list of (line_string, obj) tuples, current location) tuple."""

        lines: list[tuple[str, Atspi.Accessible | None]] = []
        self._context = self.get_or_create_context(script)
        location = self._context.get_current_location()
        self._context.go_to_start_of(flat_review.Context.WINDOW)
        string = self._context.get_current_line_string()
        while string is not None:
            obj = self._context.get_current_object()
            lines.append((string.rstrip("\n"), obj))
            if not self._context.go_next_line():
                break
            string = self._context.get_current_line_string()
        return lines, location

    @dbus_service.command
    def say_all(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        notify_user: bool = True,
    ) -> bool:
        """Speaks the contents of the entire window."""

        tokens = [
            "FLAT REVIEW PRESENTER: say_all. Script:",
            script,
            "Event:",
            event,
            "notify_user:",
            notify_user,
        ]
        debug.print_tokens(debug.LEVEL_INFO, tokens, True)

        for string, obj in self._get_all_lines(script, event)[0]:
            if not string.isspace():
                presentation_manager.get_manager().speak_accessible_text(obj, string)

        self._last_input_event = event
        return True

    @dbus_service.command
    def show_contents(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        notify_user: bool = True,
    ) -> bool:
        """Displays the entire flat review contents in a text view."""

        tokens = [
            "FLAT REVIEW PRESENTER: show_contents. Script:",
            script,
            "Event:",
            event,
            "notify_user:",
            notify_user,
        ]
        debug.print_tokens(debug.LEVEL_INFO, tokens, True)

        line_tuples, location = self._get_all_lines(script, event)
        text = "\n".join(string for string, _obj in line_tuples)
        title = guilabels.FLAT_REVIEW_CONTENTS
        self._gui = FlatReviewContextGUI(script, title, text, location)
        self._gui.show_gui()
        self._last_input_event = event
        return True

    @dbus_service.command
    def copy_to_clipboard(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        notify_user: bool = True,
    ) -> bool:
        """Copies the string just presented to the clipboard."""

        tokens = [
            "FLAT REVIEW PRESENTER: copy_to_clipboard. Script:",
            script,
            "Event:",
            event,
            "notify_user:",
            notify_user,
        ]
        debug.print_tokens(debug.LEVEL_INFO, tokens, True)

        if not self.is_active():
            if notify_user:
                presentation_manager.get_manager().present_message(messages.FLAT_REVIEW_NOT_IN)
            return True

        clipboard.get_presenter().set_text(self._current_contents.rstrip("\n"))
        if notify_user:
            presentation_manager.get_manager().present_message(messages.FLAT_REVIEW_COPIED)
        self._last_input_event = event
        return True

    @dbus_service.command
    def append_to_clipboard(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        notify_user: bool = True,
    ) -> bool:
        """Appends the string just presented to the clipboard."""

        tokens = [
            "FLAT REVIEW PRESENTER: append_to_clipboard. Script:",
            script,
            "Event:",
            event,
            "notify_user:",
            notify_user,
        ]
        debug.print_tokens(debug.LEVEL_INFO, tokens, True)

        if not self.is_active():
            if notify_user:
                presentation_manager.get_manager().present_message(messages.FLAT_REVIEW_NOT_IN)
            return True

        clipboard.get_presenter().append_text(self._current_contents.rstrip("\n"))
        if notify_user:
            presentation_manager.get_manager().present_message(messages.FLAT_REVIEW_APPENDED)
        self._last_input_event = event
        return True

    def create_preferences_grid(self) -> FlatReviewPreferencesGrid:
        """Returns the GtkGrid containing the Flat Review preferences UI."""

        # pylint: disable-next=import-outside-toplevel
        from .flat_review_presenter_preferences_grid import FlatReviewPreferencesGrid

        return FlatReviewPreferencesGrid(self)

    @gsettings_registry.get_registry().gsetting(
        key=KEY_RESTRICTED,
        schema="flat-review",
        gtype="b",
        default=False,
        summary="Restrict flat review to current object",
        migration_key="flatReviewIsRestricted",
    )
    @dbus_service.getter
    def get_is_restricted(self) -> bool:
        """Returns whether flat review is restricted to the current object."""

        return self._get_setting(self.KEY_RESTRICTED, False)

    @dbus_service.setter
    def set_is_restricted(self, value: bool) -> bool:
        """Sets whether flat review is restricted to the current object."""

        msg = f"FLAT REVIEW PRESENTER: Setting is-restricted to {value}."
        debug.print_message(debug.LEVEL_INFO, msg, True)
        gsettings_registry.get_registry().set_runtime_value(
            self._SCHEMA, self.KEY_RESTRICTED, value
        )
        return True

    @gsettings_registry.get_registry().gsetting(
        key=KEY_SPEAK_UPDATES,
        schema="flat-review",
        gtype="b",
        default=False,
        summary="Speak content changes at the flat review location",
    )
    @dbus_service.getter
    def get_speaks_updates(self) -> bool:
        """Returns whether changes at the review location are spoken automatically."""

        return self._get_setting(self.KEY_SPEAK_UPDATES, False)

    @dbus_service.setter
    def set_speaks_updates(self, value: bool) -> bool:
        """Sets whether changes at the review location are spoken automatically."""

        msg = f"FLAT REVIEW PRESENTER: Setting speak-updates to {value}."
        debug.print_message(debug.LEVEL_INFO, msg, True)
        gsettings_registry.get_registry().set_runtime_value(
            self._SCHEMA, self.KEY_SPEAK_UPDATES, value
        )
        return True

    @gsettings_registry.get_registry().gsetting(
        key=KEY_DISPLAY_UPDATES,
        schema="flat-review",
        gtype="b",
        default=True,
        summary="Refresh braille for content changes at the flat review location",
    )
    @dbus_service.getter
    def get_displays_updates(self) -> bool:
        """Returns whether changes at the review location refresh braille automatically."""

        return self._get_setting(self.KEY_DISPLAY_UPDATES, True)

    @dbus_service.setter
    def set_displays_updates(self, value: bool) -> bool:
        """Sets whether changes at the review location refresh braille automatically."""

        msg = f"FLAT REVIEW PRESENTER: Setting display-updates to {value}."
        debug.print_message(debug.LEVEL_INFO, msg, True)
        gsettings_registry.get_registry().set_runtime_value(
            self._SCHEMA, self.KEY_DISPLAY_UPDATES, value
        )
        return True

    @gsettings_registry.get_registry().gsetting(
        key=KEY_FOCUS_TRACKING,
        schema="flat-review",
        genum="org.gnome.Orca.FocusTracking",
        default="auto",
        summary="When flat review should follow the focus/caret location",
    )
    @dbus_service.getter
    def get_focus_tracking(self) -> UInt32:
        """Returns the flat review focus-tracking mode as a FocusTracking value."""

        nick = gsettings_registry.get_registry().layered_lookup(
            self._SCHEMA,
            self.KEY_FOCUS_TRACKING,
            "",
            genum="org.gnome.Orca.FocusTracking",
            default="auto",
        )
        values = gsettings_registry.get_registry().get_enum_values("org.gnome.Orca.FocusTracking")
        if values and nick in values:
            return values[nick]
        return FocusTracking.AUTO.value

    @dbus_service.setter
    def set_focus_tracking(self, value: UInt32) -> bool:
        """Sets the flat review focus-tracking mode."""

        msg = f"FLAT REVIEW PRESENTER: Setting focus-tracking to {value}."
        debug.print_message(debug.LEVEL_INFO, msg, True)
        mode = FocusTracking(value)
        gsettings_registry.get_registry().set_runtime_value(
            self._SCHEMA, self.KEY_FOCUS_TRACKING, mode.name.lower()
        )
        return True

    @dbus_service.command
    def toggle_restrict(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        notify_user: bool = True,
    ) -> bool:
        """Toggles the restricting of flat review to the current object."""

        tokens = [
            "FLAT REVIEW PRESENTER: toggle_restrict. Script:",
            script,
            "Event:",
            event,
            "notify_user:",
            notify_user,
        ]
        debug.print_tokens(debug.LEVEL_INFO, tokens, True)

        self._restrict = not self._restrict
        self.set_is_restricted(self._restrict)

        if self._restrict:
            if notify_user:
                presentation_manager.get_manager().present_message(messages.FLAT_REVIEW_RESTRICTED)
        elif notify_user:
            presentation_manager.get_manager().present_message(messages.FLAT_REVIEW_UNRESTRICTED)
        if self.is_active():
            # Reset the context
            self._context = None
            self.start()

        self._last_input_event = event
        return True

    def _line_presentation(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        speech_type: int = 1,
    ) -> bool:
        """Presents the current line."""

        self._context = self.get_or_create_context(script)
        line_string = self._context.get_current_line_string()

        if not isinstance(event, input_event.BrailleEvent):
            presenter = presentation_manager.get_manager()
            if not line_string or line_string == "\n":
                presenter.speak_message(messages.BLANK)
            elif line_string.isspace():
                presenter.speak_message(messages.WHITE_SPACE)
            else:
                indentation = speech_presenter.get_presenter().get_indentation_description(
                    line_string
                )
                if indentation:
                    presenter.speak_message(indentation)
                if line_string.isupper() and (speech_type < 2 or speech_type > 3):
                    presenter.speak_accessible_text(
                        self._context.get_current_object(),
                        line_string,
                        self._context.get_current_line_start_offset(),
                    )
                elif speech_type == 2:
                    presenter.spell_item(
                        line_string,
                        self._context.get_current_object(),
                        self._context.get_current_line_start_offset(),
                    )
                elif speech_type == 3:
                    presenter.spell_phonetically(
                        line_string,
                        self._context.get_current_object(),
                        self._context.get_current_line_start_offset(),
                    )
                else:
                    presenter.speak_accessible_text(
                        self._context.get_current_object(),
                        line_string,
                        self._context.get_current_line_start_offset(),
                    )

        focus_manager.get_manager().emit_region_changed(
            self._context.get_current_object(),
            mode=focus_manager.FLAT_REVIEW,
        )
        self._update_braille(script)
        self._last_presented_unit = flat_review.Context.LINE
        self._current_contents = line_string
        return True

    def _item_presentation(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        speech_type: int = 1,
    ) -> bool:
        """Presents the current item/word."""

        self._context = self.get_or_create_context(script)
        word_string = self._context.get_current_word_string()
        if not isinstance(event, input_event.BrailleEvent):
            presenter = presentation_manager.get_manager()
            if not word_string or word_string == "\n":
                presenter.speak_message(messages.BLANK)
            else:
                line_string = self._context.get_current_line_string()
                if line_string == "\n":
                    presenter.speak_message(messages.BLANK)
                elif word_string.isspace():
                    presenter.speak_message(messages.WHITE_SPACE)
                elif speech_type == 2:
                    presenter.spell_item(
                        word_string,
                        self._context.get_current_object(),
                        self._context.get_current_word_start_offset(),
                    )
                elif speech_type == 3:
                    presenter.spell_phonetically(
                        word_string,
                        self._context.get_current_object(),
                        self._context.get_current_word_start_offset(),
                    )
                elif (
                    speech_type == 1
                    and (offset := self._context.get_current_word_start_offset()) is not None
                ):
                    speech_presenter.get_presenter().speak_phrase(
                        script,
                        self._context.get_current_object(),
                        offset,
                        offset + len(word_string),
                        word_string,
                    )

        focus_manager.get_manager().emit_region_changed(
            self._context.get_current_object(),
            mode=focus_manager.FLAT_REVIEW,
        )
        self._update_braille(script)
        self._last_presented_unit = flat_review.Context.WORD
        self._current_contents = word_string
        return True

    def _character_presentation(
        self,
        script: default.Script,
        event: input_event.InputEvent | None = None,
        speech_type: int = 1,
    ) -> bool:
        """Presents the current character."""

        focus = focus_manager.get_manager().get_locus_of_focus()
        if not self._context and AXObject.supports_text(focus):
            char_string, offset, _end_offset = AXText.get_character_at_offset(focus)
            obj = focus
        else:
            self._context = self.get_or_create_context(script)
            char_string = self._context.get_current_character_string()
            obj = self._context.get_current_object()
            offset = self._context.get_current_text_offset()
        if not isinstance(event, input_event.BrailleEvent):
            presenter = presentation_manager.get_manager()
            if not char_string or (char_string == "\n" and speech_type != 3):
                presenter.speak_message(messages.BLANK)
            elif speech_type == 3:
                presenter.speak_message(messages.UNICODE % f"{ord(char_string):04x}")
            elif speech_type == 2:
                presenter.spell_phonetically(char_string, obj, offset if offset >= 0 else None)
            elif obj is not None and offset >= 0:
                presenter.speak_character_at_offset(obj, offset, char_string)
            else:
                presenter.speak_character(char_string)

        if not self._context:
            return True

        focus_manager.get_manager().emit_region_changed(
            self._context.get_current_object(),
            mode=focus_manager.FLAT_REVIEW,
        )
        self._update_braille(script)
        self._last_presented_unit = flat_review.Context.CHAR
        self._current_contents = char_string
        return True


class FlatReviewContextGUI:
    """Presents the entire flat review context in a text view"""

    def __init__(
        self,
        script: default.Script,
        title: str,
        text: str,
        location: tuple[int, int, int, int],
    ) -> None:
        self._script: default.Script = script
        self._gui: Gtk.Dialog = self._create_dialog(title, text, location)

    def _create_dialog(
        self,
        title: str,
        text: str,
        location: tuple[int, int, int, int],
    ) -> Gtk.Dialog:
        """Creates the dialog."""

        dialog = Gtk.Dialog(
            title,
            None,
            Gtk.DialogFlags.MODAL,
            (Gtk.STOCK_CLOSE, Gtk.ResponseType.CLOSE),
        )
        dialog.set_default_size(800, 600)

        scrolled_window = Gtk.ScrolledWindow()
        scrolled_window.set_policy(Gtk.PolicyType.AUTOMATIC, Gtk.PolicyType.AUTOMATIC)
        scrolled_window.set_hexpand(True)
        scrolled_window.set_vexpand(True)

        textbuffer = Gtk.TextBuffer()
        textbuffer.set_text(text)

        line_index, _zone_index, word_index, char_index = location
        start_iter = textbuffer.get_start_iter()
        start_iter.forward_lines(line_index)
        for _ in range(word_index):
            start_iter.forward_word_end()
            # This is needed to get past any punctuation. Note that we cannot check starts_word
            # here. Example: The letter after an apostrophe is reported as a word start.
            while not start_iter.get_char().isspace():
                if not start_iter.forward_char():
                    break

        # The text iter word can start with one or more spaces. Move to the beginning of the flat
        # review word before advancing by character.
        while not start_iter.starts_word():
            if not start_iter.forward_char():
                break

        start_iter.forward_chars(char_index)
        textbuffer.place_cursor(start_iter)

        textview = Gtk.TextView(buffer=textbuffer)
        textview.set_wrap_mode(Gtk.WrapMode.WORD)
        scrolled_window.add(textview)  # pylint: disable=no-member
        dialog.get_content_area().pack_start(scrolled_window, True, True, 0)
        dialog.connect("response", self.on_response)
        return dialog

    def on_response(self, _dialog: Gtk.Dialog, response: Gtk.ResponseType) -> None:
        """Handler for the 'response' signal of the dialog."""

        if response == Gtk.ResponseType.CLOSE:
            self._gui.destroy()

    def show_gui(self) -> None:
        """Shows the dialog."""

        self._gui.show_all()  # pylint: disable=no-member
        self._gui.present_with_time(time.time())


_presenter: FlatReviewPresenter = FlatReviewPresenter()


def get_presenter() -> FlatReviewPresenter:
    """Returns the Flat Review Presenter"""

    return _presenter
