use std::{any::Any, sync::Arc};

use crate::{
    emath::{Align, Pos2, Rect, Vec2},
    menu, Context, CursorIcon, Id, LayerId, PointerButton, Sense, Ui, WidgetRect, WidgetText,
};

// ----------------------------------------------------------------------------

/// The result of adding a widget to a [`Ui`].
///
/// A [`Response`] lets you know whether or not a widget is being hovered, clicked or dragged.
/// It also lets you easily show a tooltip on hover.
///
/// Whenever something gets added to a [`Ui`], a [`Response`] object is returned.
/// [`ui.add`] returns a [`Response`], as does [`ui.button`], and all similar shortcuts.
///
/// ⚠️ The `Response` contains a clone of [`Context`], and many methods lock the `Context`.
/// It can therefor be a deadlock to use `Context` from within a context-locking closures,
/// such as [`Context::input`].
#[derive(Clone, Debug)]
pub struct Response {
    // CONTEXT:
    /// Used for optionally showing a tooltip and checking for more interactions.
    pub ctx: Context,

    // IN:
    /// Which layer the widget is part of.
    pub layer_id: LayerId,

    /// The [`Id`] of the widget/area this response pertains.
    pub id: Id,

    /// The area of the screen we are talking about.
    pub rect: Rect,

    /// The rectangle sensing interaction.
    ///
    /// This is sometimes smaller than [`Self::rect`] because of clipping
    /// (e.g. when inside a scroll area).
    pub interact_rect: Rect,

    /// The senses (click and/or drag) that the widget was interested in (if any).
    ///
    /// Note: if [`Self::enabled`] is `false`, then
    /// the widget _effectively_ doesn't sense anything,
    /// but can still have the same `Sense`.
    /// This is because the sense informs the styling of the widget,
    /// but we don't want to change the style when a widget is disabled
    /// (that is handled by the `Painter` directly).
    pub sense: Sense,

    /// Was the widget enabled?
    /// If `false`, there was no interaction attempted (not even hover).
    #[doc(hidden)]
    pub enabled: bool,

    // OUT:
    /// The pointer is above this widget with no other blocking it.
    #[doc(hidden)]
    pub contains_pointer: bool,

    /// The pointer is hovering above this widget or the widget was clicked/tapped this frame.
    #[doc(hidden)]
    pub hovered: bool,

    /// The widget is highlighted via a call to [`Self::highlight`] or [`Context::highlight_widget`].
    #[doc(hidden)]
    pub highlighted: bool,

    /// This widget was clicked this frame.
    ///
    /// Which pointer and how many times we don't know,
    /// and ask [`crate::InputState`] about at runtime.
    ///
    /// This is only set to true if the widget was clicked
    /// by an actual mouse.
    #[doc(hidden)]
    pub clicked: bool,

    /// This widget should act as if clicked due
    /// to something else than a click.
    ///
    /// This is set to true if the widget has keyboard focus and
    /// the user hit the Space or Enter key.
    #[doc(hidden)]
    pub fake_primary_click: bool,

    /// This widget was long-pressed on a touch screen to simulate a secondary click.
    #[doc(hidden)]
    pub long_touched: bool,

    /// The widget started being dragged this frame.
    #[doc(hidden)]
    pub drag_started: bool,

    /// The widget is being dragged.
    #[doc(hidden)]
    pub dragged: bool,

    /// The widget was being dragged, but now it has been released.
    #[doc(hidden)]
    pub drag_stopped: bool,

    /// Is the pointer button currently down on this widget?
    /// This is true if the pointer is pressing down or dragging a widget
    #[doc(hidden)]
    pub is_pointer_button_down_on: bool,

    /// Where the pointer (mouse/touch) were when when this widget was clicked or dragged.
    /// `None` if the widget is not being interacted with.
    #[doc(hidden)]
    pub interact_pointer_pos: Option<Pos2>,

    /// Was the underlying data changed?
    ///
    /// e.g. the slider was dragged, text was entered in a [`TextEdit`](crate::TextEdit) etc.
    /// Always `false` for something like a [`Button`](crate::Button).
    #[doc(hidden)]
    pub changed: bool,
}

impl Response {
    /// Returns true if this widget was clicked this frame by the primary button.
    ///
    /// A click is registered when the mouse or touch is released within
    /// a certain amount of time and distance from when and where it was pressed.
    ///
    /// This will also return true if the widget was clicked via accessibility integration,
    /// or if the widget had keyboard focus and the use pressed Space/Enter.
    ///
    /// Note that the widget must be sensing clicks with [`Sense::click`].
    /// [`crate::Button`] senses clicks; [`crate::Label`] does not (unless you call [`crate::Label::sense`]).
    ///
    /// You can use [`Self::interact`] to sense more things *after* adding a widget.
    #[inline(always)]
    pub fn clicked(&self) -> bool {
        self.fake_primary_click || self.clicked_by(PointerButton::Primary)
    }

    /// Returns true if this widget was clicked this frame by the given mouse button.
    ///
    /// This will NOT return true if the widget was "clicked" via
    /// some accessibility integration, or if the widget had keyboard focus and the
    /// user pressed Space/Enter. For that, use [`Self::clicked`] instead.
    ///
    /// This will likewise ignore the press-and-hold action on touch screens.
    /// Use [`Self::secondary_clicked`] instead to also detect that.
    #[inline]
    pub fn clicked_by(&self, button: PointerButton) -> bool {
        self.clicked && self.ctx.input(|i| i.pointer.button_clicked(button))
    }

    /// Returns true if this widget was clicked this frame by the secondary mouse button (e.g. the right mouse button).
    ///
    /// This also returns true if the widget was pressed-and-held on a touch screen.
    #[inline]
    pub fn secondary_clicked(&self) -> bool {
        self.long_touched || self.clicked_by(PointerButton::Secondary)
    }

    /// Was this long-pressed on a touch screen?
    ///
    /// Usually you want to check [`Self::secondary_clicked`] instead.
    #[inline]
    pub fn long_touched(&self) -> bool {
        self.long_touched
    }

    /// Returns true if this widget was clicked this frame by the middle mouse button.
    #[inline]
    pub fn middle_clicked(&self) -> bool {
        self.clicked_by(PointerButton::Middle)
    }

    /// Returns true if this widget was double-clicked this frame by the primary button.
    #[inline]
    pub fn double_clicked(&self) -> bool {
        self.double_clicked_by(PointerButton::Primary)
    }

    /// Returns true if this widget was triple-clicked this frame by the primary button.
    #[inline]
    pub fn triple_clicked(&self) -> bool {
        self.triple_clicked_by(PointerButton::Primary)
    }

    /// Returns true if this widget was double-clicked this frame by the given button.
    #[inline]
    pub fn double_clicked_by(&self, button: PointerButton) -> bool {
        self.clicked && self.ctx.input(|i| i.pointer.button_double_clicked(button))
    }

    /// Returns true if this widget was triple-clicked this frame by the given button.
    #[inline]
    pub fn triple_clicked_by(&self, button: PointerButton) -> bool {
        self.clicked && self.ctx.input(|i| i.pointer.button_triple_clicked(button))
    }

    /// `true` if there was a click *outside* the rect of this widget.
    ///
    /// Clicks on widgets contained in this one counts as clicks inside this widget,
    /// so that clicking a button in an area will not be considered as clicking "elsewhere" from the area.
    pub fn clicked_elsewhere(&self) -> bool {
        // We do not use self.clicked(), because we want to catch all clicks within our frame,
        // even if we aren't clickable (or even enabled).
        // This is important for windows and such that should close then the user clicks elsewhere.
        self.ctx.input(|i| {
            let pointer = &i.pointer;

            if pointer.any_click() {
                if self.contains_pointer || self.hovered {
                    false
                } else if let Some(pos) = pointer.interact_pos() {
                    !self.interact_rect.contains(pos)
                } else {
                    false // clicked without a pointer, weird
                }
            } else {
                false
            }
        })
    }

    /// Was the widget enabled?
    /// If false, there was no interaction attempted
    /// and the widget should be drawn in a gray disabled look.
    #[inline(always)]
    pub fn enabled(&self) -> bool {
        self.enabled
    }

    /// The pointer is hovering above this widget or the widget was clicked/tapped this frame.
    ///
    /// In contrast to [`Self::contains_pointer`], this will be `false` whenever some other widget is being dragged.
    /// `hovered` is always `false` for disabled widgets.
    #[inline(always)]
    pub fn hovered(&self) -> bool {
        self.hovered
    }

    /// Returns true if the pointer is contained by the response rect, and no other widget is covering it.
    ///
    /// In contrast to [`Self::hovered`], this can be `true` even if some other widget is being dragged.
    /// This means it is useful for styling things like drag-and-drop targets.
    /// `contains_pointer` can also be `true` for disabled widgets.
    ///
    /// This is slightly different from [`Ui::rect_contains_pointer`] and [`Context::rect_contains_pointer`], in that
    /// [`Self::contains_pointer`] also checks that no other widget is covering this response rectangle.
    #[inline(always)]
    pub fn contains_pointer(&self) -> bool {
        self.contains_pointer
    }

    /// The widget is highlighted via a call to [`Self::highlight`] or [`Context::highlight_widget`].
    #[doc(hidden)]
    #[inline(always)]
    pub fn highlighted(&self) -> bool {
        self.highlighted
    }

    /// This widget has the keyboard focus (i.e. is receiving key presses).
    ///
    /// This function only returns true if the UI as a whole (e.g. window)
    /// also has the keyboard focus. That makes this function suitable
    /// for style choices, e.g. a thicker border around focused widgets.
    pub fn has_focus(&self) -> bool {
        self.ctx.input(|i| i.focused) && self.ctx.memory(|mem| mem.has_focus(self.id))
    }

    /// True if this widget has keyboard focus this frame, but didn't last frame.
    pub fn gained_focus(&self) -> bool {
        self.ctx.memory(|mem| mem.gained_focus(self.id))
    }

    /// The widget had keyboard focus and lost it,
    /// either because the user pressed tab or clicked somewhere else,
    /// or (in case of a [`crate::TextEdit`]) because the user pressed enter.
    ///
    /// ```
    /// # egui::__run_test_ui(|ui| {
    /// # let mut my_text = String::new();
    /// # fn do_request(_: &str) {}
    /// let response = ui.text_edit_singleline(&mut my_text);
    /// if response.lost_focus() && ui.input(|i| i.key_pressed(egui::Key::Enter)) {
    ///     do_request(&my_text);
    /// }
    /// # });
    /// ```
    pub fn lost_focus(&self) -> bool {
        self.ctx.memory(|mem| mem.lost_focus(self.id))
    }

    /// Request that this widget get keyboard focus.
    pub fn request_focus(&self) {
        self.ctx.memory_mut(|mem| mem.request_focus(self.id));
    }

    /// Surrender keyboard focus for this widget.
    pub fn surrender_focus(&self) {
        self.ctx.memory_mut(|mem| mem.surrender_focus(self.id));
    }

    /// Did a drag on this widgets begin this frame?
    ///
    /// This is only true if the widget sense drags.
    /// If the widget also senses clicks, this will only become true if the pointer has moved a bit.
    ///
    /// This will only be true for a single frame.
    #[inline]
    pub fn drag_started(&self) -> bool {
        self.drag_started
    }

    /// Did a drag on this widgets by the button begin this frame?
    ///
    /// This is only true if the widget sense drags.
    /// If the widget also senses clicks, this will only become true if the pointer has moved a bit.
    ///
    /// This will only be true for a single frame.
    #[inline]
    pub fn drag_started_by(&self, button: PointerButton) -> bool {
        self.drag_started() && self.ctx.input(|i| i.pointer.button_down(button))
    }

    /// The widget is being dragged.
    ///
    /// To find out which button(s), use [`Self::dragged_by`].
    ///
    /// If the widget is only sensitive to drags, this is `true` as soon as the pointer presses down on it.
    /// If the widget is also sensitive to drags, this won't be true until the pointer has moved a bit,
    /// or the user has pressed down for long enough.
    /// See [`crate::input_state::PointerState::is_decidedly_dragging`] for details.
    ///
    /// If you want to avoid the delay, use [`Self::is_pointer_button_down_on`] instead.
    ///
    /// If the widget is NOT sensitive to drags, this will always be `false`.
    /// [`crate::DragValue`] senses drags; [`crate::Label`] does not (unless you call [`crate::Label::sense`]).
    /// You can use [`Self::interact`] to sense more things *after* adding a widget.
    #[inline(always)]
    pub fn dragged(&self) -> bool {
        self.dragged
    }

    /// See [`Self::dragged`].
    #[inline]
    pub fn dragged_by(&self, button: PointerButton) -> bool {
        self.dragged() && self.ctx.input(|i| i.pointer.button_down(button))
    }

    /// The widget was being dragged, but now it has been released.
    #[inline]
    pub fn drag_stopped(&self) -> bool {
        self.drag_stopped
    }

    /// The widget was being dragged by the button, but now it has been released.
    pub fn drag_stopped_by(&self, button: PointerButton) -> bool {
        self.drag_stopped() && self.ctx.input(|i| i.pointer.button_released(button))
    }

    /// The widget was being dragged, but now it has been released.
    #[inline]
    #[deprecated = "Renamed 'dragged_stopped'"]
    pub fn drag_released(&self) -> bool {
        self.drag_stopped
    }

    /// The widget was being dragged by the button, but now it has been released.
    #[deprecated = "Renamed 'dragged_stopped_by'"]
    pub fn drag_released_by(&self, button: PointerButton) -> bool {
        self.drag_stopped_by(button)
    }

    /// If dragged, how many points were we dragged and in what direction?
    #[inline]
    pub fn drag_delta(&self) -> Vec2 {
        if self.dragged() {
            let mut delta = self.ctx.input(|i| i.pointer.delta());
            if let Some(scaling) = self
                .ctx
                .memory(|m| m.layer_transforms.get(&self.layer_id).map(|t| t.scaling))
            {
                delta /= scaling;
            }
            delta
        } else {
            Vec2::ZERO
        }
    }

    /// If dragged, how far did the mouse move?
    /// This will use raw mouse movement if provided by the integration, otherwise will fall back to [`Response::drag_delta`]
    /// Raw mouse movement is unaccelerated and unclamped by screen boundaries, and does not relate to any position on the screen.
    /// This may be useful in certain situations such as draggable values and 3D cameras, where screen position does not matter.
    #[inline]
    pub fn drag_motion(&self) -> Vec2 {
        if self.dragged() {
            self.ctx
                .input(|i| i.pointer.motion().unwrap_or(i.pointer.delta()))
        } else {
            Vec2::ZERO
        }
    }

    /// If the user started dragging this widget this frame, store the payload for drag-and-drop.
    #[doc(alias = "drag and drop")]
    pub fn dnd_set_drag_payload<Payload: Any + Send + Sync>(&self, payload: Payload) {
        if self.drag_started() {
            crate::DragAndDrop::set_payload(&self.ctx, payload);
        }

        if self.hovered() && !self.sense.click {
            // Things that can be drag-dropped should use the Grab cursor icon,
            // but if the thing is _also_ clickable, that can be annoying.
            self.ctx.set_cursor_icon(CursorIcon::Grab);
        }
    }

    /// Drag-and-Drop: Return what is being held over this widget, if any.
    ///
    /// Only returns something if [`Self::contains_pointer`] is true,
    /// and the user is drag-dropping something of this type.
    #[doc(alias = "drag and drop")]
    pub fn dnd_hover_payload<Payload: Any + Send + Sync>(&self) -> Option<Arc<Payload>> {
        // NOTE: we use `response.contains_pointer` here instead of `hovered`, because
        // `hovered` is always false when another widget is being dragged.
        if self.contains_pointer() {
            crate::DragAndDrop::payload::<Payload>(&self.ctx)
        } else {
            None
        }
    }

    /// Drag-and-Drop: Return what is being dropped onto this widget, if any.
    ///
    /// Only returns something if [`Self::contains_pointer`] is true,
    /// the user is drag-dropping something of this type,
    /// and they released it this frame
    #[doc(alias = "drag and drop")]
    pub fn dnd_release_payload<Payload: Any + Send + Sync>(&self) -> Option<Arc<Payload>> {
        // NOTE: we use `response.contains_pointer` here instead of `hovered`, because
        // `hovered` is always false when another widget is being dragged.
        if self.contains_pointer() && self.ctx.input(|i| i.pointer.any_released()) {
            crate::DragAndDrop::take_payload::<Payload>(&self.ctx)
        } else {
            None
        }
    }

    /// Where the pointer (mouse/touch) were when when this widget was clicked or dragged.
    ///
    /// `None` if the widget is not being interacted with.
    #[inline]
    pub fn interact_pointer_pos(&self) -> Option<Pos2> {
        self.interact_pointer_pos
    }

    /// If it is a good idea to show a tooltip, where is pointer?
    ///
    /// None if the pointer is outside the response area.
    #[inline]
    pub fn hover_pos(&self) -> Option<Pos2> {
        if self.hovered() {
            let mut pos = self.ctx.input(|i| i.pointer.hover_pos())?;
            if let Some(transform) = self
                .ctx
                .memory(|m| m.layer_transforms.get(&self.layer_id).cloned())
            {
                pos = transform * pos;
            }
            Some(pos)
        } else {
            None
        }
    }

    /// Is the pointer button currently down on this widget?
    ///
    /// This is true if the pointer is pressing down or dragging a widget,
    /// even when dragging outside the widget.
    ///
    /// This could also be thought of as "is this widget being interacted with?".
    #[inline(always)]
    pub fn is_pointer_button_down_on(&self) -> bool {
        self.is_pointer_button_down_on
    }

    /// Was the underlying data changed?
    ///
    /// e.g. the slider was dragged, text was entered in a [`TextEdit`](crate::TextEdit) etc.
    /// Always `false` for something like a [`Button`](crate::Button).
    ///
    /// Can sometimes be `true` even though the data didn't changed
    /// (e.g. if the user entered a character and erased it the same frame).
    ///
    /// This is not set if the *view* of the data was changed.
    /// For instance, moving the cursor in a [`TextEdit`](crate::TextEdit) does not set this to `true`.
    #[inline(always)]
    pub fn changed(&self) -> bool {
        self.changed
    }

    /// Report the data shown by this widget changed.
    ///
    /// This must be called by widgets that represent some mutable data,
    /// e.g. checkboxes, sliders etc.
    ///
    /// This should be called when the *content* changes, but not when the view does.
    /// So we call this when the text of a [`crate::TextEdit`], but not when the cursors changes.
    #[inline(always)]
    pub fn mark_changed(&mut self) {
        self.changed = true;
    }

    /// Show this UI if the widget was hovered (i.e. a tooltip).
    ///
    /// The text will not be visible if the widget is not enabled.
    /// For that, use [`Self::on_disabled_hover_ui`] instead.
    ///
    /// If you call this multiple times the tooltips will stack underneath the previous ones.
    #[doc(alias = "tooltip")]
    pub fn on_hover_ui(self, add_contents: impl FnOnce(&mut Ui)) -> Self {
        if self.enabled && self.should_show_hover_ui() {
            crate::containers::show_tooltip_for(
                &self.ctx,
                self.id.with("__tooltip"),
                &self.rect,
                add_contents,
            );
        }
        self
    }

    /// Show this UI when hovering if the widget is disabled.
    pub fn on_disabled_hover_ui(self, add_contents: impl FnOnce(&mut Ui)) -> Self {
        if !self.enabled && self.should_show_hover_ui() {
            crate::containers::show_tooltip_for(
                &self.ctx,
                self.id.with("__tooltip"),
                &self.rect,
                add_contents,
            );
        }
        self
    }

    /// Like `on_hover_ui`, but show the ui next to cursor.
    pub fn on_hover_ui_at_pointer(self, add_contents: impl FnOnce(&mut Ui)) -> Self {
        if self.enabled && self.should_show_hover_ui() {
            crate::containers::show_tooltip_at_pointer(
                &self.ctx,
                self.id.with("__tooltip"),
                add_contents,
            );
        }
        self
    }

    /// Was the tooltip open last frame?
    pub fn is_tooltip_open(&self) -> bool {
        crate::popup::was_tooltip_open_last_frame(&self.ctx, self.id.with("__tooltip"))
    }

    fn should_show_hover_ui(&self) -> bool {
        if self.ctx.memory(|mem| mem.everything_is_visible()) {
            return true;
        }

        if self.context_menu_opened() {
            return false;
        }

        if self.enabled {
            if !self.hovered || !self.ctx.input(|i| i.pointer.has_pointer()) {
                return false;
            }
        } else if !self.ctx.rect_contains_pointer(self.layer_id, self.rect) {
            return false;
        }

        if self.ctx.style().interaction.show_tooltips_only_when_still {
            // We only show the tooltip when the mouse pointer is still,
            // but once shown we keep showing it until the mouse leaves the parent.

            if !self.ctx.input(|i| i.pointer.is_still()) && !self.is_tooltip_open() {
                // wait for mouse to stop
                self.ctx.request_repaint();
                return false;
            }
        }

        if !self.is_tooltip_open() {
            let time_til_tooltip = self.ctx.style().interaction.tooltip_delay
                - self.ctx.input(|i| i.pointer.time_since_last_movement());

            if 0.0 < time_til_tooltip {
                // Wait until the mouse has been still for a while
                if let Ok(duration) = std::time::Duration::try_from_secs_f32(time_til_tooltip) {
                    self.ctx.request_repaint_after(duration);
                }
                return false;
            }
        }

        // We don't want tooltips of things while we are dragging them,
        // but we do want tooltips while holding down on an item on a touch screen.
        if self
            .ctx
            .input(|i| i.pointer.any_down() && i.pointer.has_moved_too_much_for_a_click)
        {
            return false;
        }

        true
    }

    /// Like `on_hover_text`, but show the text next to cursor.
    #[doc(alias = "tooltip")]
    pub fn on_hover_text_at_pointer(self, text: impl Into<WidgetText>) -> Self {
        self.on_hover_ui_at_pointer(|ui| {
            ui.add(crate::widgets::Label::new(text));
        })
    }

    /// Show this text if the widget was hovered (i.e. a tooltip).
    ///
    /// The text will not be visible if the widget is not enabled.
    /// For that, use [`Self::on_disabled_hover_text`] instead.
    ///
    /// If you call this multiple times the tooltips will stack underneath the previous ones.
    #[doc(alias = "tooltip")]
    pub fn on_hover_text(self, text: impl Into<WidgetText>) -> Self {
        self.on_hover_ui(|ui| {
            ui.add(crate::widgets::Label::new(text));
        })
    }

    /// Highlight this widget, to make it look like it is hovered, even if it isn't.
    ///
    /// The highlight takes one frame to take effect if you call this after the widget has been fully rendered.
    ///
    /// See also [`Context::highlight_widget`].
    #[inline]
    pub fn highlight(mut self) -> Self {
        self.ctx.highlight_widget(self.id);
        self.highlighted = true;
        self
    }

    /// Show this text when hovering if the widget is disabled.
    pub fn on_disabled_hover_text(self, text: impl Into<WidgetText>) -> Self {
        self.on_disabled_hover_ui(|ui| {
            ui.add(crate::widgets::Label::new(text));
        })
    }

    /// When hovered, use this icon for the mouse cursor.
    #[inline]
    pub fn on_hover_cursor(self, cursor: CursorIcon) -> Self {
        if self.hovered() {
            self.ctx.set_cursor_icon(cursor);
        }
        self
    }

    /// When hovered or dragged, use this icon for the mouse cursor.
    #[inline]
    pub fn on_hover_and_drag_cursor(self, cursor: CursorIcon) -> Self {
        if self.hovered() || self.dragged() {
            self.ctx.set_cursor_icon(cursor);
        }
        self
    }

    /// Sense more interactions (e.g. sense clicks on a [`Response`] returned from a label).
    ///
    /// The interaction will occur on the same plane as the original widget,
    /// i.e. if the response was from a widget behind button, the interaction will also be behind that button.
    /// egui gives priority to the _last_ added widget (the one on top gets clicked first).
    ///
    /// Note that this call will not add any hover-effects to the widget, so when possible
    /// it is better to give the widget a [`Sense`] instead, e.g. using [`crate::Label::sense`].
    ///
    /// Using this method on a `Response` that is the result of calling `union` on multiple `Response`s
    /// is undefined behavior.
    ///
    /// ```
    /// # egui::__run_test_ui(|ui| {
    /// let horiz_response = ui.horizontal(|ui| {
    ///     ui.label("hello");
    /// }).response;
    /// assert!(!horiz_response.clicked()); // ui's don't sense clicks by default
    /// let horiz_response = horiz_response.interact(egui::Sense::click());
    /// if horiz_response.clicked() {
    ///     // The background behind the label was clicked
    /// }
    /// # });
    /// ```
    #[must_use]
    pub fn interact(&self, sense: Sense) -> Self {
        if (self.sense | sense) == self.sense {
            // Early-out: we already sense everything we need to sense.
            return self.clone();
        }

        self.ctx.create_widget(WidgetRect {
            layer_id: self.layer_id,
            id: self.id,
            rect: self.rect,
            interact_rect: self.interact_rect,
            sense: self.sense | sense,
            enabled: self.enabled,
        })
    }

    /// Adjust the scroll position until this UI becomes visible.
    ///
    /// If `align` is [`Align::TOP`] it means "put the top of the rect at the top of the scroll area", etc.
    /// If `align` is `None`, it'll scroll enough to bring the UI into view.
    ///
    /// See also: [`Ui::scroll_to_cursor`], [`Ui::scroll_to_rect`]. [`Ui::scroll_with_delta`].
    ///
    /// ```
    /// # egui::__run_test_ui(|ui| {
    /// egui::ScrollArea::vertical().show(ui, |ui| {
    ///     for i in 0..1000 {
    ///         let response = ui.button("Scroll to me");
    ///         if response.clicked() {
    ///             response.scroll_to_me(Some(egui::Align::Center));
    ///         }
    ///     }
    /// });
    /// # });
    /// ```
    pub fn scroll_to_me(&self, align: Option<Align>) {
        self.ctx.frame_state_mut(|state| {
            state.scroll_target[0] = Some((self.rect.x_range(), align));
            state.scroll_target[1] = Some((self.rect.y_range(), align));
        });
    }

    /// For accessibility.
    ///
    /// Call after interacting and potential calls to [`Self::mark_changed`].
    pub fn widget_info(&self, make_info: impl Fn() -> crate::WidgetInfo) {
        use crate::output::OutputEvent;
        let event = if self.clicked() {
            Some(OutputEvent::Clicked(make_info()))
        } else if self.double_clicked() {
            Some(OutputEvent::DoubleClicked(make_info()))
        } else if self.triple_clicked() {
            Some(OutputEvent::TripleClicked(make_info()))
        } else if self.gained_focus() {
            Some(OutputEvent::FocusGained(make_info()))
        } else if self.changed {
            Some(OutputEvent::ValueChanged(make_info()))
        } else {
            None
        };
        if let Some(event) = event {
            self.output_event(event);
        } else {
            #[cfg(feature = "accesskit")]
            self.ctx.accesskit_node_builder(self.id, |builder| {
                self.fill_accesskit_node_from_widget_info(builder, make_info());
            });
        }
    }

    pub fn output_event(&self, event: crate::output::OutputEvent) {
        #[cfg(feature = "accesskit")]
        self.ctx.accesskit_node_builder(self.id, |builder| {
            self.fill_accesskit_node_from_widget_info(builder, event.widget_info().clone());
        });
        self.ctx.output_mut(|o| o.events.push(event));
    }

    #[cfg(feature = "accesskit")]
    pub(crate) fn fill_accesskit_node_common(&self, builder: &mut accesskit::NodeBuilder) {
        builder.set_bounds(accesskit::Rect {
            x0: self.rect.min.x.into(),
            y0: self.rect.min.y.into(),
            x1: self.rect.max.x.into(),
            y1: self.rect.max.y.into(),
        });
        if self.sense.focusable {
            builder.add_action(accesskit::Action::Focus);
        }
        if self.sense.click && builder.default_action_verb().is_none() {
            builder.set_default_action_verb(accesskit::DefaultActionVerb::Click);
        }
    }

    #[cfg(feature = "accesskit")]
    fn fill_accesskit_node_from_widget_info(
        &self,
        builder: &mut accesskit::NodeBuilder,
        info: crate::WidgetInfo,
    ) {
        use crate::WidgetType;
        use accesskit::{Checked, Role};

        self.fill_accesskit_node_common(builder);
        builder.set_role(match info.typ {
            WidgetType::Label => Role::StaticText,
            WidgetType::Link => Role::Link,
            WidgetType::TextEdit => Role::TextInput,
            WidgetType::Button | WidgetType::ImageButton | WidgetType::CollapsingHeader => {
                Role::Button
            }
            WidgetType::Checkbox => Role::CheckBox,
            WidgetType::RadioButton => Role::RadioButton,
            WidgetType::SelectableLabel => Role::ToggleButton,
            WidgetType::ComboBox => Role::ComboBox,
            WidgetType::Slider => Role::Slider,
            WidgetType::DragValue => Role::SpinButton,
            WidgetType::ColorButton => Role::ColorWell,
            WidgetType::ProgressIndicator => Role::ProgressIndicator,
            WidgetType::Other => Role::Unknown,
        });
        if let Some(label) = info.label {
            builder.set_name(label);
        }
        if let Some(value) = info.current_text_value {
            builder.set_value(value);
        }
        if let Some(value) = info.value {
            builder.set_numeric_value(value);
        }
        if let Some(selected) = info.selected {
            builder.set_checked(if selected {
                Checked::True
            } else {
                Checked::False
            });
        } else if matches!(info.typ, WidgetType::Checkbox) {
            // Indeterminate state
            builder.set_checked(Checked::Mixed);
        }
    }

    /// Associate a label with a control for accessibility.
    ///
    /// # Example
    ///
    /// ```
    /// # egui::__run_test_ui(|ui| {
    /// # let mut text = "Arthur".to_string();
    /// ui.horizontal(|ui| {
    ///     let label = ui.label("Your name: ");
    ///     ui.text_edit_singleline(&mut text).labelled_by(label.id);
    /// });
    /// # });
    /// ```
    pub fn labelled_by(self, id: Id) -> Self {
        #[cfg(feature = "accesskit")]
        self.ctx.accesskit_node_builder(self.id, |builder| {
            builder.push_labelled_by(id.accesskit_id());
        });
        #[cfg(not(feature = "accesskit"))]
        {
            let _ = id;
        }

        self
    }

    /// Response to secondary clicks (right-clicks) by showing the given menu.
    ///
    /// Make sure the widget senses clicks (e.g. [`crate::Button`] does, [`crate::Label`] does not).
    ///
    /// ```
    /// # use egui::{Label, Sense};
    /// # egui::__run_test_ui(|ui| {
    /// let response = ui.add(Label::new("Right-click me!").sense(Sense::click()));
    /// response.context_menu(|ui| {
    ///     if ui.button("Close the menu").clicked() {
    ///         ui.close_menu();
    ///     }
    /// });
    /// # });
    /// ```
    ///
    /// See also: [`Ui::menu_button`] and [`Ui::close_menu`].
    pub fn context_menu(&self, add_contents: impl FnOnce(&mut Ui)) -> Option<InnerResponse<()>> {
        menu::context_menu(self, add_contents)
    }

    /// Returns whether a context menu is currently open for this widget.
    ///
    /// See [`Self::context_menu`].
    pub fn context_menu_opened(&self) -> bool {
        menu::context_menu_opened(self)
    }

    /// Draw a debug rectangle over the response displaying the response's id and whether it is
    /// enabled and/or hovered.
    ///
    /// This function is intended for debugging purpose and can be useful, for example, in case of
    /// widget id instability.
    ///
    /// Color code:
    /// - Blue: Enabled but not hovered
    /// - Green: Enabled and hovered
    /// - Red: Disabled
    pub fn paint_debug_info(&self) {
        self.ctx.debug_painter().debug_rect(
            self.rect,
            if self.hovered {
                crate::Color32::DARK_GREEN
            } else if self.enabled {
                crate::Color32::BLUE
            } else {
                crate::Color32::RED
            },
            format!("{:?}", self.id),
        );
    }
}

impl Response {
    /// A logical "or" operation.
    /// For instance `a.union(b).hovered` means "was either a or b hovered?".
    ///
    /// The resulting [`Self::id`] will come from the first (`self`) argument.
    ///
    /// You may not call [`Self::interact`] on the resulting `Response`.
    pub fn union(&self, other: Self) -> Self {
        assert!(self.ctx == other.ctx);
        crate::egui_assert!(
            self.layer_id == other.layer_id,
            "It makes no sense to combine Responses from two different layers"
        );
        Self {
            ctx: other.ctx,
            layer_id: self.layer_id,
            id: self.id,
            rect: self.rect.union(other.rect),
            interact_rect: self.interact_rect.union(other.interact_rect),
            sense: self.sense.union(other.sense),
            enabled: self.enabled || other.enabled,
            contains_pointer: self.contains_pointer || other.contains_pointer,
            hovered: self.hovered || other.hovered,
            highlighted: self.highlighted || other.highlighted,
            clicked: self.clicked || other.clicked,
            fake_primary_click: self.fake_primary_click || other.fake_primary_click,
            long_touched: self.long_touched || other.long_touched,
            drag_started: self.drag_started || other.drag_started,
            dragged: self.dragged || other.dragged,
            drag_stopped: self.drag_stopped || other.drag_stopped,
            is_pointer_button_down_on: self.is_pointer_button_down_on
                || other.is_pointer_button_down_on,
            interact_pointer_pos: self.interact_pointer_pos.or(other.interact_pointer_pos),
            changed: self.changed || other.changed,
        }
    }
}

impl Response {
    /// Returns a response with a modified [`Self::rect`].
    #[inline]
    pub fn with_new_rect(self, rect: Rect) -> Self {
        Self { rect, ..self }
    }
}

/// See [`Response::union`].
///
/// To summarize the response from many widgets you can use this pattern:
///
/// ```
/// use egui::*;
/// fn draw_vec2(ui: &mut Ui, v: &mut Vec2) -> Response {
///     ui.add(DragValue::new(&mut v.x)) | ui.add(DragValue::new(&mut v.y))
/// }
/// ```
///
/// Now `draw_vec2(ui, foo).hovered` is true if either [`DragValue`](crate::DragValue) were hovered.
impl std::ops::BitOr for Response {
    type Output = Self;

    fn bitor(self, rhs: Self) -> Self {
        self.union(rhs)
    }
}

/// See [`Response::union`].
///
/// To summarize the response from many widgets you can use this pattern:
///
/// ```
/// # egui::__run_test_ui(|ui| {
/// # let (widget_a, widget_b, widget_c) = (egui::Label::new("a"), egui::Label::new("b"), egui::Label::new("c"));
/// let mut response = ui.add(widget_a);
/// response |= ui.add(widget_b);
/// response |= ui.add(widget_c);
/// if response.hovered() { ui.label("You hovered at least one of the widgets"); }
/// # });
/// ```
impl std::ops::BitOrAssign for Response {
    fn bitor_assign(&mut self, rhs: Self) {
        *self = self.union(rhs);
    }
}

// ----------------------------------------------------------------------------

/// Returned when we wrap some ui-code and want to return both
/// the results of the inner function and the ui as a whole, e.g.:
///
/// ```
/// # egui::__run_test_ui(|ui| {
/// let inner_resp = ui.horizontal(|ui| {
///     ui.label("Blah blah");
///     42
/// });
/// inner_resp.response.on_hover_text("You hovered the horizontal layout");
/// assert_eq!(inner_resp.inner, 42);
/// # });
/// ```
#[derive(Debug)]
pub struct InnerResponse<R> {
    /// What the user closure returned.
    pub inner: R,

    /// The response of the area.
    pub response: Response,
}

impl<R> InnerResponse<R> {
    #[inline]
    pub fn new(inner: R, response: Response) -> Self {
        Self { inner, response }
    }
}