flux_tui/components/

combobox.rs

use std::sync::atomic::{AtomicBool, Ordering};

use super::*;
use crate::canvas::*;

use std::num::NonZero;
use std::rc::Rc;

use as_any::Downcast;
use crossterm::event::{Event, KeyCode};
use unicode_width::UnicodeWidthStr;

pub type ComboboxSelectionChangedCallback<T> = dyn Fn(&mut Combobox<T>);
pub type ComboboxKeyHandler<T> = fn(&mut Combobox<T>, event: &mut WindowEvent);

/// Combobox contains a list of values of which one can be selected
/// The selected value can be changed by using the Left and Right buttons
/// Focus highlights the Combobox's text
///
/// Design (Border is part of the component):
/// ```text
/// ┌─┬─────────────┬─┐
/// │<│ Text [2/28] │>│
/// └─┴─────────────┴─┘
/// ```
pub struct Combobox<T: PartialEq + 'static> {
	has_focus: bool,
	// Keeps track if the border has actually been drawn
	border_visible: AtomicBool,
	border_bg: Option<Color>,
	border_fg: Option<Color>,
	base: WidgetBase,
	items: Vec<DisplayValue<T>>,
	focus: usize,
	callback: Rc<ComboboxSelectionChangedCallback<T>>,
	key_handler: ComboboxKeyHandler<T>,
}

impl<T: PartialEq> Default for Combobox<T> {
	fn default() -> Self {
		let mut s = Self {
			items: Vec::new(),
			has_focus: false,
			border_visible: AtomicBool::default(),
			border_fg: None,
			border_bg: None,
			base: WidgetBase::default(),
			focus: usize::MIN,
			callback: Rc::new(Self::default_callback),
			key_handler: Self::default_key_handler,
		};
		s.base.border = BorderStyle::Custom(Self::render_border, Thickness::new(1, 3, 3, 1));
		s.base.constraints.x.min = NonZero::new(3).unwrap();
		s.base.constraints.y.min = NonZero::<TSize>::MIN;
		s.base.constraints.y.max = Size::Fixed(NonZero::<TSize>::MIN);
		s
	}
}

impl<T: PartialEq> Combobox<T> {
	pub const INDICATOR_LEFT: Grapheme = ScrollViewer::ARROW_LEFT;
	pub const INDICATOR_RIGHT: Grapheme = ScrollViewer::ARROW_RIGHT;
	pub const DEFAULT_BORDER: BorderKind = BorderKind::Solid;

	pub fn default_callback(_: &mut Self) {}

	pub fn default_key_handler(&mut self, event: &mut WindowEvent) {
		if let Event::Key(k) = event.raw() {
			if self.base.enabled {
				if k.code == KeyCode::Left {
					self.select_previous();
					event.handled = true;
				}
				else if k.code == KeyCode::Right {
					self.select_next();
					event.handled = true;
				}
			}
		}
	}

	pub fn set_key_handler(&mut self, f: ComboboxKeyHandler<T>) {
		self.key_handler = f;
	}

	pub fn set_selection_changed_callback<F: Fn(&mut Self) + 'static>(&mut self, callback: F) {
		self.callback = Rc::new(callback);
	}

	pub fn get_value(&self) -> Option<&DisplayValue<T>> {
		self.items.get(self.focus)
	}

	pub fn set_border_fg(&mut self, color: Option<Color>) {
		self.border_fg = color;
	}

	pub fn set_border_bg(&mut self, color: Option<Color>) {
		self.border_bg = color;
	}

	/// Selects the next possible element
	pub fn select_next(&mut self) {
		if self.focus < self.items.len() - 1 {
			let cb = self.callback.clone();
			self.focus += 1;
			cb(self);
		}
	}

	/// Selects the previous possible element
	pub fn select_previous(&mut self) {
		if self.focus > 0 {
			let cb = self.callback.clone();
			self.focus -= 1;
			cb(self);
		}
	}

	fn render_border(w: &dyn Window, mut canvas: BorderCanvas<'_>) {
		let slf: &Self = w.downcast_ref().unwrap();
		slf.border_visible.store(true, Ordering::Release);

		let corners = Self::DEFAULT_BORDER.corner_style();
		let lines = Self::DEFAULT_BORDER.line_style();
		let conns = Self::DEFAULT_BORDER.connector_style();
		let connector_bottom_lr = conns[2];
		let connector_top_lr = conns[3];
		{
			let w = canvas.size().x;
			canvas
				.get_glyph(0, 1)
				.unwrap()
				.set_grapheme(lines[1])
				.unwrap();
			canvas
				.get_glyph(1, 1)
				.unwrap()
				.set_grapheme(Self::INDICATOR_LEFT)
				.unwrap();
			canvas
				.get_glyph(2, 1)
				.unwrap()
				.set_grapheme(lines[1])
				.unwrap();

			canvas
				.get_glyph(w - 3, 1)
				.unwrap()
				.set_grapheme(lines[1])
				.unwrap();
			canvas
				.get_glyph(w - 2, 1)
				.unwrap()
				.set_grapheme(Self::INDICATOR_RIGHT)
				.unwrap();
			canvas
				.get_glyph(w - 1, 1)
				.unwrap()
				.set_grapheme(lines[1])
				.unwrap();
		}


		let mut row = canvas.get_row(0).unwrap();
		row.get(0).unwrap().set_grapheme(corners[0]).unwrap();
		row.get(1).unwrap().set_grapheme(lines[0]).unwrap();
		row.get(2)
			.unwrap()
			.set_grapheme(connector_bottom_lr)
			.unwrap();
		row.get(row.length() - 1)
			.unwrap()
			.set_grapheme(corners[1])
			.unwrap();
		row.get(row.length() - 2)
			.unwrap()
			.set_grapheme(lines[0])
			.unwrap();
		row.get(row.length() - 3)
			.unwrap()
			.set_grapheme(connector_bottom_lr)
			.unwrap();
		for idx in 3..row.length() - 3 {
			row.get(idx).unwrap().set_grapheme(lines[0]).unwrap();
		}

		let mut row = canvas.get_row(canvas.size().y - 1).unwrap();
		row.get(0).unwrap().set_grapheme(corners[2]).unwrap();
		row.get(1).unwrap().set_grapheme(lines[0]).unwrap();
		row.get(2).unwrap().set_grapheme(connector_top_lr).unwrap();
		row.get(row.length() - 1)
			.unwrap()
			.set_grapheme(corners[3])
			.unwrap();
		row.get(row.length() - 2)
			.unwrap()
			.set_grapheme(lines[0])
			.unwrap();
		row.get(row.length() - 3)
			.unwrap()
			.set_grapheme(connector_top_lr)
			.unwrap();

		for idx in 3..row.length() - 3 {
			row.get(idx).unwrap().set_grapheme(lines[0]).unwrap();
		}

		if let Some(color) = slf.border_fg {
			canvas.fill_foreground(color);
		}
		if let Some(color) = slf.border_bg {
			canvas.fill_background(color);
		}
	}
}

impl<T: PartialEq> ItemCollection<DisplayValue<T>> for Combobox<T> {
	type Index = usize;

	fn add_item(&mut self, item: DisplayValue<T>) {
		self.items.push(item);
		self.items
			.sort_by(|a, b| a.display.as_str().cmp(b.display.as_str()));
		self.provoke_changed_property(WindowProperty::Children);
	}

	fn remove_item(&mut self, item: &DisplayValue<T>) {
		if let Some(idx) = self.items.iter().position(|x| x.value == item.value) {
			self.items.remove(idx);
			if idx == self.focus {
				let cb = self.callback.clone();
				cb(self);
			}
		}
	}

	fn remove_at(&mut self, index: Self::Index) -> DisplayValue<T> {
		self.items.remove(index)
	}

	fn get_item(&mut self, index: Self::Index) -> Option<&DisplayValue<T>> {
		self.items.get(index)
	}

	fn clear_items(&mut self) {
		if !self.items.is_empty() {
			self.items.clear();
			self.focus = usize::MIN;
			self.provoke_changed_property(WindowProperty::Focus);
			let cb = self.callback.clone();
			cb(self);
		}
	}

	fn items(&self) -> Self::Index {
		self.items.len()
	}
}

impl<T: PartialEq> Window for Combobox<T> {
	fn render(&self, canvas: &mut Canvas) {
		let has_border = self.border_visible.load(Ordering::Relaxed);

		if !has_border {
			let mut row = canvas.get_row(0, GlyphWidth::Half).unwrap();
			row.get(0)
				.unwrap()
				.set_grapheme(Self::INDICATOR_LEFT)
				.unwrap();
			row.get(row.length() - 1)
				.unwrap()
				.set_grapheme(Self::INDICATOR_RIGHT)
				.unwrap();
		}

		let mut row = canvas.get_row_variable_width(0).unwrap();

		if let Some(v) = self.items.get(self.focus) {
			let cb_index = format!("[{}/{}]", self.focus + 1, self.items.len());
			let index_w = cb_index.width() as TSize;
			let w = v.display.width() as TSize;
			let width = row.width();
			let style = Style::Reverse.when(self.has_focus);

			row = row.with_custom_width(width).unwrap();
			if row.width() > w + index_w {
				row.skip((row.width() - w - (index_w + 1)) / 2);
			}

			row.add_string(
				&v.display,
				None,
				None,
				style,
				Some(VariableWidthGlyphRow::DOT3_REPLACEMENT),
			)
			.unwrap();
			row.skip(1);
			row.add_string(
				&cb_index,
				self.base.colors.base_fg,
				self.base.colors.base_bg,
				Style::default(),
				None,
			)
			.ok();
		}
	}

	fn handle_event(&mut self, event: &mut WindowEvent) {
		match event.raw() {
			Event::Resize(_, _) => self.border_visible.store(false, Ordering::Relaxed),
			Event::FocusGained => self.has_focus = true,
			Event::FocusLost => self.has_focus = false,
			_ => (self.key_handler)(self, event),
		}
	}

	fn is_enabled(&self) -> bool {
		self.base.enabled
	}
}

impl<T: PartialEq> WindowLayout for Combobox<T> {
	fn desired_size(&self, available_size: TPoint) -> TPoint {
		self.base.desired_size(available_size)
	}

	fn border(&self) -> BorderStyle {
		self.base.border
	}

	fn alignment(&self) -> (HorizontalAlignment, VerticalAlignment) {
		self.base.alignment
	}

	fn is_visible(&self) -> bool {
		self.base.visibility
	}

	fn margin(&self) -> Thickness {
		self.base.margin
	}
}

impl<T: PartialEq + 'static> HasWindowUID for Combobox<T> {
	fn uid(&self) -> WindowUID {
		self.base.uid
	}
}

impl<T: PartialEq> Widget for Combobox<T> {
	fn set_visibility(&mut self, visibility: bool) {
		self.base.visibility = visibility;
		self.provoke_changed_property(WindowProperty::IsVisible);
	}

	fn set_width(&mut self, width: Size) {
		self.base.size.x = width;
		self.provoke_changed_property(WindowProperty::Size);
	}

	fn set_height(&mut self, height: Size) {
		let _ = height;
	}

	fn set_margin(&mut self, margin: Thickness) {
		self.base.margin = margin;
		self.provoke_changed_property(WindowProperty::Margin);
	}

	/// This is ignored
	fn set_border(&mut self, border: BorderStyle) {
		let _ = border;
	}

	fn set_alignment(&mut self, horizontal: HorizontalAlignment, vertical: VerticalAlignment) {
		self.base.alignment = (horizontal, vertical);
		self.provoke_changed_property(WindowProperty::Alignment);
	}

	fn set_enabled_state(&mut self, is_enabled: bool) {
		self.base.enabled = is_enabled;
	}

	fn set_width_constraint(&mut self, width: SizeConstraint) {
		self.base.constraints.x = width;
		self.provoke_changed_property(WindowProperty::Size);
	}

	fn set_height_constraint(&mut self, height: SizeConstraint) {
		self.base.constraints.y = height;
		self.provoke_changed_property(WindowProperty::Size);
	}
}

impl<T: PartialEq> WidgetColors for Combobox<T> {
	fn set_disabled_color(&mut self, color: Option<Color>) {
		self.base.colors.disabled = color;
	}

	fn set_base_fg_color(&mut self, color: Option<Color>) {
		self.base.colors.base_fg = color;
	}

	fn set_base_bg_color(&mut self, color: Option<Color>) {
		self.base.colors.base_bg = color;
	}
}