cursive_multiple_choice_view/

lib.rs

use cursive_core::{
	align::{Align, HAlign, VAlign},
	direction,
	event::{Callback, Event, EventResult, Key, MouseButton, MouseEvent},
	Rect,
	style::{PaletteStyle, Style, StyleType},
	utils::markup::StyledString,
	view::{CannotFocus, View},
	Cursive, Printer, Vec2, With,
};
use std::borrow::Borrow;
use std::cmp::{min, Ordering};
use std::sync::atomic::AtomicUsize;
use std::sync::Arc;

type SelectCallback<T> = dyn Fn(&mut Cursive, &T) + Send + Sync;

/// View to make a selection from multiple items.
///
/// It contains a list of values of type T, with associated labels.
///
pub struct MultipleChoiceView<T = String> {
	// The core of the view: we store a list of items
	// `Item` is more or less a `(String, Arc<T>)`.
	items: Vec<Item<T>>,

	// When disabled, we cannot change selection.
	enabled: bool,

	// Callbacks may need to manipulate focus, so give it some mutability.
	focus: Arc<AtomicUsize>,

	// If true, highlight the selection even when inactive (not focused).
	// If false, selection will be drawn like regular text if inactive.
	inactive_highlight: bool,

	// This is a custom callback to include a &T.
	// It will be called whenever "Enter" is pressed or when an item is clicked.
	on_submit: Option<Arc<SelectCallback<T>>>,

	// This callback is called when the selection is changed.
	// TODO: add the previous selection? Indices?
	on_select: Option<Arc<SelectCallback<T>>>,

	// If `true`, when a character is pressed, jump to the next item starting
	// with this character.
	autojump: bool,

	align: Align,

	// Indicators showing whether the item is chosen or not.
	choice_indicators: [&'static str; 2],

	last_size: Vec2,

	// Cache of required_size. Set to None when it needs to be recomputed.
	last_required_size: Option<Vec2>,
}

impl<T: 'static + Send + Sync> Default for MultipleChoiceView<T> {
	fn default() -> Self {
		Self::new()
	}
}

impl<T: 'static + Send + Sync> MultipleChoiceView<T> {
	cursive_core::impl_enabled!(self.enabled);

	/// Creates a new empty MultipleChoiceView.
	pub fn new() -> Self {
		MultipleChoiceView {
			items: Vec::new(),
			enabled: true,
			focus: Arc::new(AtomicUsize::new(0)),
			inactive_highlight: true,
			on_select: None,
			on_submit: None,
			align: Align::top_left(),
			choice_indicators: ["[ ]", "[X]"],
			autojump: false,
			last_required_size: None,
			last_size: Vec2::zero(),
		}
	}

	/// Sets the visual indicators for chosen and not chosen items.
	/// 
	/// The first indicator represents the not chosen variant.
    /// 
    /// # Examples
	///
	/// ```
	/// use cursive_core::traits::Nameable;
	/// use cursive_multiple_choice_view::MultipleChoiceView;
	///
	/// let mut multiple_choice_view: MultipleChoiceView<String> = MultipleChoiceView::new();
	/// 
	/// multiple_choice_view.set_choice_indicators(["☐", "☒"]);
	/// ```
	pub fn set_choice_indicators(&mut self, selection_indicators: [&'static str; 2]) {
		self.choice_indicators = selection_indicators;
		self.last_required_size = None;
	}

	/// Sets the visual indicators for chosen and not chosen items.
	/// 
	/// The first indicator represents the not chosen variant.
	/// 
	/// Chainable variant.
	/// 
	/// # Examples
	///
	/// ```
	/// use cursive_core::traits::Nameable;
	/// use cursive_multiple_choice_view::MultipleChoiceView;
	///
	/// let multiple_choice_view: MultipleChoiceView<String> = MultipleChoiceView::new()
	///     .with_choice_indicators(["☐", "☒"]);
	/// ```
	#[must_use]
	pub fn with_choice_indicators(self, selection_indicators: [&'static str; 2]) -> Self {
		self.with(|s| s.set_choice_indicators(selection_indicators))
	}

	/// Sets the "auto-jump" property for this view.
	///
	/// If enabled, when a key is pressed, the selection will jump to the next
	/// item beginning with the pressed letter.
	pub fn set_autojump(&mut self, autojump: bool) {
		self.autojump = autojump;
	}

	/// Sets the "auto-jump" property for this view.
	///
	/// If enabled, when a key is pressed, the selection will jump to the next
	/// item beginning with the pressed letter.
	///
	/// Chainable variant.
	#[must_use]
	pub fn autojump(self) -> Self {
		self.with(|s| s.set_autojump(true))
	}

	/// Sets the "inactive highlight" property for this view.
	///
	/// * If true (the default), the selected row will be highlighted when the
	///   view is not focused.
	/// * If false, the selected row will be printed like the others if inactive.
	pub fn set_inactive_highlight(&mut self, inactive_highlight: bool) {
		self.inactive_highlight = inactive_highlight;
	}

	/// Sets the "inactive highlight" property for this view.
	///
	/// * If true (the default), the selected row will be highlighted when the
	///   view is not focused.
	/// * If false, the selected row will be printed like the others if inactive.
	///
	/// Chainable variant.
	pub fn with_inactive_highlight(self, inactive_highlight: bool) -> Self {
		self.with(|s| s.set_inactive_highlight(inactive_highlight))
	}

	/// Returns the current status of the "inactive highlight" property.
	pub fn get_inactive_highlight(&self) -> bool {
		self.inactive_highlight
	}

	/// Sets a callback to be used when an item is selected.
	#[cursive_core::callback_helpers]
	pub fn set_on_select<F>(&mut self, cb: F)
	where
		F: Fn(&mut Cursive, &T) + 'static + Send + Sync,
	{
		self.on_select = Some(Arc::new(cb));
	}

	/// Sets a callback to be used when an item is selected.
	///
	/// Chainable variant.
	///
	/// # Examples
	///
	/// ```
	/// use cursive_core::traits::Nameable;
	/// use cursive_core::views::TextView;
	/// use cursive_multiple_choice_view::MultipleChoiceView;
	///
	/// let text_view = TextView::new("").with_name("text");
	///
	/// let multiple_choice_view = MultipleChoiceView::new()
	///     .item("One", 1)
	///     .item("Two", 2)
	///     .on_select(|s, item| {
	///         let content = match *item {
	///             1 => "Content number one",
	///             2 => "Content number two! Much better!",
	///             _ => unreachable!("no such item"),
	///         };
	///
	///         // Update the textview with the currently selected item.
	///         s.call_on_name("text", |v: &mut TextView| {
	///             v.set_content(content);
	///         })
	///         .unwrap();
	///     });
	/// ```
	#[must_use]
	pub fn on_select<F>(self, cb: F) -> Self
	where
		F: Fn(&mut Cursive, &T) + 'static + Send + Sync,
	{
		self.with(|s| s.set_on_select(cb))
	}

	/// Sets a callback to be used when `<Enter>` is pressed.
	///
	/// Also happens if the user clicks an item.
	///
	/// The item currently selected will be given to the callback.
	///
	/// Here, `V` can be `T` itself, or a type that can be borrowed from `T`.
	pub fn set_on_submit<F, V: ?Sized>(&mut self, cb: F)
	where
		F: 'static + Fn(&mut Cursive, &V) + Send + Sync,
		T: Borrow<V>,
	{
		self.on_submit = Some(Arc::new(move |s, t| {
			cb(s, t.borrow());
		}));
	}

	/// Sets a callback to be used when `<Enter>` is pressed.
	///
	/// Also happens if the user clicks an item.
	///
	/// The item currently selected will be given to the callback.
	///
	/// Chainable variant.
	///
	/// # Examples
	///
	/// ```
	/// use cursive_core::views::Dialog;
	/// use cursive_multiple_choice_view::MultipleChoiceView;
	///
	/// let multiple_choice_view = MultipleChoiceView::new()
	///     .item("One", 1)
	///     .item("Two", 2)
	///     .on_submit(|s, item| {
	///         let content = match *item {
	///             1 => "Content number one",
	///             2 => "Content number two! Much better!",
	///             _ => unreachable!("no such item"),
	///         };
	///
	///         // Show a popup whenever the user presses <Enter>.
	///         s.add_layer(Dialog::info(content));
	///     });
	/// ```
	#[must_use]
	pub fn on_submit<F, V: ?Sized>(self, cb: F) -> Self
	where
		F: Fn(&mut Cursive, &V) + 'static + Send + Sync,
		T: Borrow<V>,
	{
		self.with(|s| s.set_on_submit(cb))
	}

	/// Sets the alignment for this view.
	///
	/// # Examples
	///
	/// ```
	/// use cursive_core::align;
	/// use cursive_multiple_choice_view::MultipleChoiceView;
	///
	/// let multiple_choice_view = MultipleChoiceView::new()
	///     .item("One", 1)
	///     .align(align::Align::top_center());
	/// ```
	#[must_use]
	pub fn align(mut self, align: Align) -> Self {
		self.align = align;

		self
	}

	/// Sets the vertical alignment for this view.
	/// (If the view is given too much space vertically.)
	#[must_use]
	pub fn v_align(mut self, v: VAlign) -> Self {
		self.align.v = v;

		self
	}

	/// Sets the horizontal alignment for this view.
	#[must_use]
	pub fn h_align(mut self, h: HAlign) -> Self {
		self.align.h = h;

		self
	}

	/// Returns the value of the currently selected item.
	///
	/// Returns `None` if the list is empty.
	pub fn selection(&self) -> Option<Arc<T>> {
		let focus = self.focus();
		if self.len() <= focus {
			None
		} else {
			Some(Arc::clone(&self.items[focus].value))
		}
	}

	/// Removes all items from this view.
	pub fn clear(&mut self) {
		self.items.clear();
		self.focus.store(0, std::sync::atomic::Ordering::Relaxed);
		self.last_required_size = None;
	}

	/// Adds a item to the list, with given label and value.
	///
	/// # Examples
	///
	/// ```
	/// use cursive_multiple_choice_view::MultipleChoiceView;
	///
	/// let mut multiple_choice_view = MultipleChoiceView::new();
	///
	/// multiple_choice_view.add_item("Item 1", 1);
	/// multiple_choice_view.add_item("Item 2", 2);
	/// ```
	pub fn add_item<S: Into<StyledString>>(&mut self, label: S, value: T) {
		self.add_item_with_choice(label, value, false);
	}

	/// Gets an item at given idx or None.
	///
	/// ```
	/// use cursive_core::views::TextView;
	/// use cursive_multiple_choice_view::MultipleChoiceView;
	/// use cursive_core::Cursive;
	/// let select = MultipleChoiceView::new().item("Short", 1);
	/// assert_eq!(select.get_item(0), Some(("Short", &1)));
	/// ```
	pub fn get_item(&self, i: usize) -> Option<(&str, &T)> {
		self.iter().nth(i)
	}

	/// Gets a mut item at given idx or None.
	pub fn get_item_mut(&mut self, i: usize) -> Option<(&mut StyledString, &mut T)> {
		if i >= self.items.len() {
			None
		} else {
			self.last_required_size = None;
			let item = &mut self.items[i];
			if let Some(t) = Arc::get_mut(&mut item.value) {
				let label = &mut item.label;
				Some((label, t))
			} else {
				None
			}
		}
	}

	/// Iterate mutably on the items in this view.
	///
	/// Returns an iterator with each item and their labels.
	///
	/// In some cases some items will need to be cloned (for example if a
	/// `Arc<T>` is still alive after calling `MultipleChoiceView::selection()`).
	///
	/// If `T` does not implement `Clone`, check `MultipleChoiceView::try_iter_mut()`.
	pub fn iter_mut(&mut self) -> impl Iterator<Item = (&mut StyledString, &mut T)>
	where
		T: Clone,
	{
		self.last_required_size = None;
		self.items
			.iter_mut()
			.map(|item| (&mut item.label, Arc::make_mut(&mut item.value)))
	}

	/// Try to iterate mutably on the items in this view.
	///
	/// Returns an iterator with each item and their labels.
	///
	/// Some items may not be returned mutably, for example if a `Arc<T>` is
	/// still alive after calling `MultipleChoiceView::selection()`.
	pub fn try_iter_mut(&mut self) -> impl Iterator<Item = (&mut StyledString, Option<&mut T>)> {
		self.last_required_size = None;
		self.items
			.iter_mut()
			.map(|item| (&mut item.label, Arc::get_mut(&mut item.value)))
	}

	/// Iterate on the items in this view.
	///
	/// Returns an iterator with each item and their labels.
	pub fn iter(&self) -> impl Iterator<Item = (&str, &T)> {
		self.items
			.iter()
			.map(|item| (item.label.source(), &*item.value))
	}

	/// Adds a item to the list, with given label, value and whether it should
	/// be marked as chosen.
	///
	/// # Examples
	///
	/// ```
	/// use cursive_multiple_choice_view::MultipleChoiceView;
	///
	/// let mut multiple_choice_view = MultipleChoiceView::new();
	///
	/// multiple_choice_view.add_item_with_choice("Item 1", 1, true);
	/// multiple_choice_view.add_item_with_choice("Item 2", 2, false);
	/// ```
	pub fn add_item_with_choice<S: Into<StyledString>>(&mut self, label: S, value: T, chosen: bool) {
		self.items.push(Item::new(label.into(), value, chosen));
		self.last_required_size = None;
	}

	/// Removes an item from the list.
	///
	/// Returns a callback in response to the selection change.
	///
	/// You should run this callback with a `&mut Cursive`.
	pub fn remove_item(&mut self, id: usize) -> Callback {
		self.items.remove(id);
		self.last_required_size = None;
		let focus = self.focus();
		(focus >= id && focus > 0)
			.then(|| {
				self.set_focus(focus - 1);
				self.make_select_cb()
			})
			.flatten()
			.unwrap_or_else(Callback::dummy)
	}

	/// Inserts an item at position `index`, shifting all elements after it to
	/// the right.
	pub fn insert_item<S>(&mut self, index: usize, label: S, value: T)
	where
		S: Into<StyledString>,
	{
		self.insert_item_with_choice(index, label, value, false);
	}

	pub fn insert_item_with_choice<S>(&mut self, index: usize, label: S, value: T, chosen: bool)
	where
		S: Into<StyledString>,
	{
		self.items.insert(index, Item::new(label.into(), value, chosen));
		let focus = self.focus();
		// Do not increase focus if we were empty with focus=0.
		if focus >= index && !self.items.is_empty() {
			self.set_focus(focus + 1);
		}
		self.last_required_size = None;
	}

	/// Chainable variant of add_item
	///
	/// # Examples
	///
	/// ```
	/// use cursive_multiple_choice_view::MultipleChoiceView;
	///
	/// let multiple_choice_view = MultipleChoiceView::new()
	///     .item("Item 1", 1)
	///     .item("Item 2", 2)
	///     .item("Surprise item", 42);
	/// ```
	#[must_use]
	pub fn item<S: Into<StyledString>>(self, label: S, value: T) -> Self {
		self.with(|s| s.add_item(label, value))
	}

	#[must_use]
	pub fn item_with_choice<S: Into<StyledString>>(self, label: S, value: T, chosen: bool) -> Self {
		self.with(|s| s.add_item_with_choice(label, value, chosen))
	}

	/// Adds all items from from an iterator.
	pub fn add_all<S, I>(&mut self, iter: I)
	where
		S: Into<StyledString>,
		I: IntoIterator<Item = (S, T)>,
	{
		for (s, t) in iter {
			self.add_item(s, t);
		}
	}

	/// Adds all items from from an iterator.
	///
	/// Chainable variant.
	///
	/// # Examples
	///
	/// ```
	/// use cursive_multiple_choice_view::MultipleChoiceView;
	///
	/// // Create a MultipleChoiceView with 100 items
	/// let multiple_choice_view =
	///     MultipleChoiceView::new().with_all((1u8..100).into_iter().map(|i| (format!("Item {}", i), i)));
	/// ```
	#[must_use]
	pub fn with_all<S, I>(self, iter: I) -> Self
	where
		S: Into<StyledString>,
		I: IntoIterator<Item = (S, T)>,
	{
		self.with(|s| s.add_all(iter))
	}

	fn get_label_decorated(&self, i: usize) -> StyledString {
		let s = self.items[i].label.source();
		let prefix = if self.items[i].chosen {
			self.choice_indicators[1]
		} else {
			self.choice_indicators[0]
		};
		StyledString::plain(format!("{} {}", prefix, s))
	}

	fn draw_item(&self, printer: &Printer, i: usize) {
		let s = self.get_label_decorated(i);
		let l = s.width();
		let x = self.align.h.get_offset(l, printer.size.x);
		printer.print_hline((0, 0), x, " ");
		printer.print_styled((x, 0), &s);
		if l < printer.size.x {
			assert!((l + x) <= printer.size.x);
			printer.print_hline((x + l, 0), printer.size.x - (l + x), " ");
		}
	}

	/// Returns the id of the item currently selected.
	///
	/// Returns `None` if the list is empty.
	pub fn selected_id(&self) -> Option<usize> {
		if self.items.is_empty() {
			None
		} else {
			Some(self.focus())
		}
	}

	/// Returns the number of items in this list.
	///
	/// # Examples
	///
	/// ```
	/// use cursive_multiple_choice_view::MultipleChoiceView;
	///
	/// let multiple_choice_view = MultipleChoiceView::new()
	///     .item("Item 1", 1)
	///     .item("Item 2", 2)
	///     .item("Item 3", 3);
	///
	/// assert_eq!(multiple_choice_view.len(), 3);
	/// ```
	pub fn len(&self) -> usize {
		self.items.len()
	}

	/// Returns `true` if this list has no item.
	///
	/// # Examples
	///
	/// ```
	/// use cursive_multiple_choice_view::MultipleChoiceView;
	///
	/// let mut multiple_choice_view = MultipleChoiceView::new();
	/// assert!(multiple_choice_view.is_empty());
	///
	/// multiple_choice_view.add_item("Item 1", 1);
	/// multiple_choice_view.add_item("Item 2", 2);
	/// assert!(!multiple_choice_view.is_empty());
	///
	/// multiple_choice_view.clear();
	/// assert!(multiple_choice_view.is_empty());
	/// ```
	pub fn is_empty(&self) -> bool {
		self.items.is_empty()
	}

	fn focus(&self) -> usize {
		self.focus.load(std::sync::atomic::Ordering::Relaxed)
	}

	fn set_focus(&mut self, focus: usize) {
		self.focus
			.store(focus, std::sync::atomic::Ordering::Relaxed);
	}

	/// Sort the current items lexicographically by their label.
	///
	/// Note that this does not change the current focus index, which means that the current
	/// selection will likely be changed by the sorting.
	///
	/// This sort is stable: items with identical label will not be reordered.
	pub fn sort_by_label(&mut self) {
		self.items
			.sort_by(|a, b| a.label.source().cmp(b.label.source()));
	}

	/// Sort the current items with the given comparator function.
	///
	/// Note that this does not change the current focus index, which means that the current
	/// selection will likely be changed by the sorting.
	///
	/// The given comparator function must define a total order for the items.
	///
	/// If the comparator function does not define a total order, then the order after the sort is
	/// unspecified.
	///
	/// This sort is stable: equal items will not be reordered.
	pub fn sort_by<F>(&mut self, mut compare: F)
	where
		F: FnMut(&T, &T) -> Ordering,
	{
		self.items.sort_by(|a, b| compare(&a.value, &b.value));
	}

	/// Sort the current items with the given key extraction function.
	///
	/// Note that this does not change the current focus index, which means that the current
	/// selection will likely be changed by the sorting.
	///
	/// This sort is stable: items with equal keys will not be reordered.
	pub fn sort_by_key<K, F>(&mut self, mut key_of: F)
	where
		F: FnMut(&T) -> K,
		K: Ord,
	{
		self.items.sort_by_key(|item| key_of(&item.value));
	}

	/// Moves the selection to the given position.
	///
	/// Returns a callback in response to the selection change.
	///
	/// You should run this callback with a `&mut Cursive`.
	pub fn set_selection(&mut self, i: usize) -> Callback {
		// TODO: Check if `i >= self.len()` ?
		// assert!(i < self.len(), "MultipleChoiceView: trying to select out-of-bound");
		// Or just cap the ID?
		let i = if self.is_empty() {
			0
		} else {
			min(i, self.len() - 1)
		};
		self.set_focus(i);

		self.make_select_cb().unwrap_or_else(Callback::dummy)
	}

	/// Sets the selection to the given position.
	///
	/// Chainable variant.
	///
	/// Does not apply `on_select` callbacks.
	#[must_use]
	pub fn selected(self, i: usize) -> Self {
		self.with(|s| {
			s.set_selection(i);
		})
	}

	/// Get all chosen items
	pub fn get_choice(&self) -> Vec<Arc<T>> {
		let mut ret = Vec::new();
		for i in &self.items {
			if i.chosen {
				ret.push(i.value.clone());
			}
		}
		ret
	}

	/// Moves the selection up by the given number of rows.
	///
	/// Returns a callback in response to the selection change.
	///
	/// You should run this callback with a `&mut Cursive`:
	///
	/// ```rust
	/// # use cursive_core::Cursive;
	/// # use cursive_multiple_choice_view::MultipleChoiceView;
	/// fn select_up(siv: &mut Cursive, view: &mut MultipleChoiceView<()>) {
	///     let cb = view.select_up(1);
	///     cb(siv);
	/// }
	/// ```
	pub fn select_up(&mut self, n: usize) -> Callback {
		self.focus_up(n);
		self.make_select_cb().unwrap_or_else(Callback::dummy)
	}

	/// Moves the selection down by the given number of rows.
	///
	/// Returns a callback in response to the selection change.
	///
	/// You should run this callback with a `&mut Cursive`.
	pub fn select_down(&mut self, n: usize) -> Callback {
		self.focus_down(n);
		self.make_select_cb().unwrap_or_else(Callback::dummy)
	}

	fn focus_up(&mut self, n: usize) {
		let focus: usize = self.focus().saturating_sub(n);
		self.set_focus(focus);
	}

	fn focus_down(&mut self, n: usize) {
		let focus = min(self.focus() + n, self.items.len().saturating_sub(1));
		self.set_focus(focus);
	}

	fn submit(&mut self) -> EventResult {
		let cb = self.on_submit.clone().unwrap();
		// We return a Callback Arc<|s| cb(s, &*v)>
		EventResult::Consumed(
			self.selection()
				.map(|v: Arc<T>| Callback::from_fn(move |s| cb(s, &v))),
		)
	}

	fn toggle_choice(&mut self) {
		if let Some(item_id) = self.selected_id() {
			self.items[item_id].toggle_choice();
		}
	}

	fn on_char_event(&mut self, c: char) -> EventResult {
		let i = {
			// * Starting from the current focus, find the first item that
			//   match the char.
			// * Cycle back to the beginning of the list when we reach the end.
			// * This is achieved by chaining twice the iterator.
			let iter = self.iter().chain(self.iter());

			// We'll do a lowercase check.
			let lower_c: Vec<char> = c.to_lowercase().collect();
			let lower_c: &[char] = &lower_c;

			if let Some((i, _)) = iter
				.enumerate()
				.skip(self.focus() + 1)
				.find(|&(_, (label, _))| label.to_lowercase().starts_with(lower_c))
			{
				i % self.len()
			} else {
				return EventResult::Ignored;
			}
		};

		self.set_focus(i);
		// Apply modulo in case we have a hit from the chained iterator
		let cb = self.set_selection(i);
		EventResult::Consumed(Some(cb))
	}

	fn on_event_regular(&mut self, event: Event) -> EventResult {
		match event {
			Event::Key(Key::Up) if self.focus() > 0 => self.focus_up(1),
			Event::Key(Key::Down) if self.focus() + 1 < self.items.len() => self.focus_down(1),
			Event::Key(Key::PageUp) => self.focus_up(10),
			Event::Key(Key::PageDown) => self.focus_down(10),
			Event::Key(Key::Home) => self.set_focus(0),
			Event::Key(Key::End) => self.set_focus(self.items.len().saturating_sub(1)),
			Event::Mouse {
				event: MouseEvent::Press(_),
				position,
				offset,
			} if position
				.checked_sub(offset)
				.map(|position| position < self.last_size && position.y < self.len())
				.unwrap_or(false) =>
			{
				self.set_focus(position.y - offset.y)
			}
			Event::Mouse {
				event: MouseEvent::Release(MouseButton::Left),
				position,
				offset,
			}  =>
			{
				self.toggle_choice();
				if self.on_submit.is_some()
				&& position
					.checked_sub(offset)
					.map(|position| position < self.last_size && position.y == self.focus())
					.unwrap_or(false)
				{
					return self.submit();
				}
			}
			Event::Key(Key::Enter) => {
				self.toggle_choice();
				if self.on_submit.is_some() {
					return self.submit();
				}
			}
			Event::Char(c) if self.autojump => return self.on_char_event(c),
			_ => return EventResult::Ignored,
		}

		EventResult::Consumed(self.make_select_cb())
	}

	/// Returns a callback from selection change.
	fn make_select_cb(&self) -> Option<Callback> {
		self.on_select.clone().and_then(|cb| {
			self.selection()
				.map(|v| Callback::from_fn(move |s| cb(s, &v)))
		})
	}
}

impl MultipleChoiceView<String> {
	/// Convenient method to use the label as value.
	pub fn add_item_str<S: Into<String>>(&mut self, label: S) {
		self.add_item_str_with_choice(label, false);
	}

	/// Convenient method to use the label as value.
	pub fn add_item_str_with_choice<S: Into<String>>(&mut self, label: S, chosen: bool) {
		let label = label.into();
		self.add_item_with_choice(label.clone(), label, chosen);
	}

	/// Convenient method to use the label unstyled text as value.
	pub fn add_item_styled<S: Into<StyledString>>(&mut self, label: S) {
		let label = label.into();

		// Accumulate the content of each span.
		let mut content = String::new();
		for span in label.spans() {
			content.push_str(span.content);
		}

		self.add_item(label, content);
	}

	/// Chainable variant of `add_item_str`.
	///
	/// # Examples
	///
	/// ```
	/// use cursive_multiple_choice_view::MultipleChoiceView;
	///
	/// let multiple_choice_view = MultipleChoiceView::new()
	///     .item_str("Paris")
	///     .item_str("New York")
	///     .item_str("Tokyo");
	/// ```
	#[must_use]
	pub fn item_str<S: Into<String>>(self, label: S) -> Self {
		self.with(|s| s.add_item_str(label))
	}

	/// Chainable variant of `add_item_str_with_choice`.
	#[must_use]
	pub fn item_str_with_choice<S: Into<String>>(self, label: S, chosen: bool) -> Self {
		self.with(|s| s.add_item_str_with_choice(label, chosen))
	}

	/// Chainable variant of `add_item_styled`.
	#[must_use]
	pub fn item_styled<S: Into<StyledString>>(self, label: S) -> Self {
		self.with(|s| s.add_item_styled(label))
	}

	/// Convenient method to use the label as value.
	pub fn insert_item_str<S>(&mut self, index: usize, label: S)
	where
		S: Into<String>,
	{
		let label = label.into();
		self.insert_item(index, label.clone(), label);
	}

	/// Adds all strings from an iterator.
	///
	/// # Examples
	///
	/// ```
	/// # use cursive_multiple_choice_view::MultipleChoiceView;
	/// let mut multiple_choice_view = MultipleChoiceView::new();
	/// multiple_choice_view.add_all_str(vec!["a", "b", "c"]);
	/// ```
	pub fn add_all_str<S, I>(&mut self, iter: I)
	where
		S: Into<String>,
		I: IntoIterator<Item = S>,
	{
		for s in iter {
			self.add_item_str(s);
		}
	}

	/// Adds all strings from an iterator.
	///
	/// Chainable variant.
	///
	/// # Examples
	///
	/// ```
	/// use cursive_multiple_choice_view::MultipleChoiceView;
	///
	/// let text = "..."; // Maybe read some config file
	///
	/// let multiple_choice_view = MultipleChoiceView::new().with_all_str(text.lines());
	/// ```
	#[must_use]
	pub fn with_all_str<S, I>(self, iter: I) -> Self
	where
		S: Into<String>,
		I: IntoIterator<Item = S>,
	{
		self.with(|s| s.add_all_str(iter))
	}
}

impl<T: 'static> MultipleChoiceView<T>
where
	T: Ord,
{
	/// Sort the current items by their natural ordering.
	///
	/// Note that this does not change the current focus index, which means that the current
	/// selection will likely be changed by the sorting.
	///
	/// This sort is stable: items that are equal will not be reordered.
	pub fn sort(&mut self) {
		self.items.sort_by(|a, b| a.value.cmp(&b.value));
	}
}

impl<T: 'static + Send + Sync> View for MultipleChoiceView<T> {
	fn draw(&self, printer: &Printer) {
		let focus = self.focus();

		let h = self.items.len();
		let offset = self.align.v.get_offset(h, printer.size.y);
		let printer = &printer.offset((0, offset));

		let enabled = self.enabled && printer.enabled;
		let active = printer.focused;

		let regular_style: StyleType = if enabled {
			Style::inherit_parent().into()
		} else {
			PaletteStyle::Secondary.into()
		};

		let highlight_style = if active {
			PaletteStyle::Highlight.into()
		} else if self.inactive_highlight {
			PaletteStyle::HighlightInactive.into()
		} else {
			regular_style
		};

		for i in 0..self.len() {
			let style = if i == focus {
				highlight_style
			} else {
				regular_style
			};

			printer.offset((0, i)).with_style(style, |printer| {
				self.draw_item(printer, i);
			});
		}
	}

	fn required_size(&mut self, _: Vec2) -> Vec2 {
		if let Some(s) = self.last_required_size {
			return s;
		}
		// Items here are not compressible.
		// So no matter what the horizontal requirements are,
		// we'll still return our longest item.
		let indicators_w = 1 + self.choice_indicators[0].len().max(self.choice_indicators[1].len());
		let w = indicators_w + self
			.items
			.iter()
			.map(|item| item.label.width())
			.max()
			.unwrap_or(1);
		let size = {
			let h = self.items.len();

			Vec2::new(w, h)
		};
		self.last_required_size = Some(size);
		size
	}

	fn on_event(&mut self, event: Event) -> EventResult {
		if !self.enabled {
			return EventResult::Ignored;
		}

		self.on_event_regular(event)
	}

	fn take_focus(&mut self, source: direction::Direction) -> Result<EventResult, CannotFocus> {
		(self.enabled && !self.items.is_empty())
			.then(|| {
				match source {
					direction::Direction::Abs(direction::Absolute::Up) => {
						self.set_focus(0);
					}
					direction::Direction::Abs(direction::Absolute::Down) => {
						self.set_focus(self.items.len().saturating_sub(1));
					}
					_ => (),
				}
				EventResult::Consumed(None)
			})
			.ok_or(CannotFocus)
	}

	fn layout(&mut self, size: Vec2) {
		self.last_size = size;
	}

	fn important_area(&self, size: Vec2) -> Rect {
		self.selected_id()
			.map(|i| Rect::from_size((0, i), (size.x, 1)))
			.unwrap_or_else(|| Rect::from_size(Vec2::zero(), size))
	}
}

// We wrap each value in a `Arc` and add a label
struct Item<T> {
	label: StyledString,
	value: Arc<T>,
	chosen: bool,
}

impl<T> Item<T> {
	fn new(label: StyledString, value: T, chosen: bool) -> Self {
		let value = Arc::new(value);
		Item {
			label,
			value,
			chosen,
		}
	}

	fn toggle_choice(&mut self) {
		if self.chosen {
			self.chosen = false;
		} else {
			self.chosen = true;
		}
	}
}

#[cursive_core::blueprint(MultipleChoiceView::<String>::new())]
struct Blueprint {
	autojump: Option<bool>,

	on_select: Option<_>,

	#[blueprint(foreach = add_item_str)]
	items: Vec<String>,
}

#[cfg(test)]
mod tests {
	use super::*;

	#[test]
	fn select_view_sorting() {
		// We add items in no particular order, from going by their label.
		let mut view = MultipleChoiceView::new();
		view.add_item_str("Y");
		view.add_item_str("Z");
		view.add_item_str("X");

		// Then sorting the list...
		view.sort_by_label();

		// ... should observe the items in sorted order.
		// And focus is NOT changed by the sorting, so the first item is "X".
		assert_eq!(view.selection(), Some(Arc::new(String::from("X"))));
		view.on_event(Event::Key(Key::Down));
		assert_eq!(view.selection(), Some(Arc::new(String::from("Y"))));
		view.on_event(Event::Key(Key::Down));
		assert_eq!(view.selection(), Some(Arc::new(String::from("Z"))));
		view.on_event(Event::Key(Key::Down));
		assert_eq!(view.selection(), Some(Arc::new(String::from("Z"))));
	}

	#[test]
	fn select_view_sorting_with_comparator() {
		// We add items in no particular order, from going by their value.
		let mut view = MultipleChoiceView::new();
		view.add_item("Y", 2);
		view.add_item("Z", 1);
		view.add_item("X", 3);

		// Then sorting the list...
		view.sort_by(|a, b| a.cmp(b));

		// ... should observe the items in sorted order.
		// And focus is NOT changed by the sorting, so the first item is "X".
		assert_eq!(view.selection(), Some(Arc::new(1)));
		view.on_event(Event::Key(Key::Down));
		assert_eq!(view.selection(), Some(Arc::new(2)));
		view.on_event(Event::Key(Key::Down));
		assert_eq!(view.selection(), Some(Arc::new(3)));
		view.on_event(Event::Key(Key::Down));
		assert_eq!(view.selection(), Some(Arc::new(3)));
	}

	#[test]
	fn select_view_sorting_by_key() {
		// We add items in no particular order, from going by their key value.
		#[derive(Eq, PartialEq, Debug)]
		struct MyStruct {
			key: i32,
		}

		let mut view = MultipleChoiceView::new();
		view.add_item("Y", MyStruct { key: 2 });
		view.add_item("Z", MyStruct { key: 1 });
		view.add_item("X", MyStruct { key: 3 });

		// Then sorting the list...
		view.sort_by_key(|s| s.key);

		// ... should observe the items in sorted order.
		// And focus is NOT changed by the sorting, so the first item is "X".
		assert_eq!(view.selection(), Some(Arc::new(MyStruct { key: 1 })));
		view.on_event(Event::Key(Key::Down));
		assert_eq!(view.selection(), Some(Arc::new(MyStruct { key: 2 })));
		view.on_event(Event::Key(Key::Down));
		assert_eq!(view.selection(), Some(Arc::new(MyStruct { key: 3 })));
		view.on_event(Event::Key(Key::Down));
		assert_eq!(view.selection(), Some(Arc::new(MyStruct { key: 3 })));
	}

	#[test]
	fn select_view_sorting_orderable_items() {
		// We add items in no particular order, from going by their value.
		let mut view = MultipleChoiceView::new();
		view.add_item("Y", 2);
		view.add_item("Z", 1);
		view.add_item("X", 3);

		// Then sorting the list...
		view.sort();

		// ... should observe the items in sorted order.
		// And focus is NOT changed by the sorting, so the first item is "X".
		assert_eq!(view.selection(), Some(Arc::new(1)));
		view.on_event(Event::Key(Key::Down));
		assert_eq!(view.selection(), Some(Arc::new(2)));
		view.on_event(Event::Key(Key::Down));
		assert_eq!(view.selection(), Some(Arc::new(3)));
		view.on_event(Event::Key(Key::Down));
		assert_eq!(view.selection(), Some(Arc::new(3)));
	}
}