flux-tui 0.5.0

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

use crossterm::event::{KeyCode, KeyModifiers};
use std::rc::Rc;
use uid::IdU64;

pub type TabViewSelectionChangedCallback = dyn Fn(&mut TabView);
pub type TabViewKeyHandler = fn(&mut TabView, event: &mut WindowEvent);

pub struct Tab {
	name: String,
	content: WindowRef,
	id: IdU64<Tab>,
}

impl Tab {
	/// Creates an unique tab for a window  - the name will be shown in the tab itself
	pub fn new<S: ToString>(name: S, content: WindowRef) -> Self {
		Self {
			name: name.to_string(),
			content,
			id: IdU64::new(),
		}
	}

	/// Returns the window inside the [Tab]
	pub fn content(&self) -> &WindowRef {
		&self.content
	}
}

/// This will only compare the internal unique IDs
impl PartialEq for Tab {
	fn eq(&self, other: &Self) -> bool {
		self.id == other.id
	}
}

#[derive(Default)]
struct TabViewColors {
	fg_highlight: Option<Color>,
	bg_highlight: Option<Color>,
}

//TODO: tabs alignment
/// The currently selected tab will have a highlighted background. All others will have the same
/// background (which is usually darker).
///
/// Design:
///
/// ```text
/// [1] Tab│[2] Tab│[3] Tab│...
///
///         -------------
///         Tab 1 content
///         -------------
///
/// ```
pub struct TabView {
	base: WidgetBase,
	tabs: Vec<Tab>,
	selected: usize,
	enumerate_tabs: bool,
	callback: Rc<TabViewSelectionChangedCallback>,
	colors: TabViewColors,
	key_handler: TabViewKeyHandler,
}

impl Default for TabView {
	fn default() -> Self {
		Self {
			base: WidgetBase::default(),
			tabs: Vec::default(),
			selected: usize::MIN,
			enumerate_tabs: false,
			callback: Rc::new(Self::default_callback),
			colors: TabViewColors::default(),
			key_handler: Self::default_key_handler,
		}
	}
}

impl ItemCollection<Tab> for TabView {
	type Index = usize;

	fn add_item(&mut self, item: Tab) {
		self.tabs.push(item);
	}

	fn remove_item(&mut self, item: &Tab) {
		let idx = self.tabs.iter().position(|x| x == item);
		if let Some(index) = idx {
			if self.selected == index {
				self.selected = usize::MIN;
				self.provoke_changed_property(WindowProperty::Focus);
			}
			self.tabs.remove(index);
			self.provoke_changed_property(WindowProperty::Children);
		}
	}

	fn remove_at(&mut self, index: Self::Index) -> Tab {
		self.tabs.remove(index)
	}

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

	fn clear_items(&mut self) {
		self.tabs.clear();
		self.selected = usize::MIN;
		self.provoke_changed_property(WindowProperty::Children);
	}

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

impl TabView {
	pub const TAB_SEPERATOR: Grapheme = BorderKind::Solid.line_style()[1];
	pub const BRACKET_OPEN: Grapheme = Grapheme::new_unchecked("[", GlyphWidth::Half);
	pub const BRACKET_CLOSE: Grapheme = Grapheme::new_unchecked("]", GlyphWidth::Half);
	pub const ANGLES_RIGHT: Grapheme = Grapheme::new_unchecked("»", GlyphWidth::Half);
	pub const ANGLES_LEFT: Grapheme = Grapheme::new_unchecked("«", GlyphWidth::Half);
	pub const MIN_TAB_WIDTH: TSize = 4;

	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 && k.modifiers.contains(KeyModifiers::CONTROL) {
				if k.code == KeyCode::Char('x') {
					self.select_previous();
					event.handled = true;
				}
				else if k.code == KeyCode::Char('y') {
					self.select_next();
					event.handled = true;
				}
			}
		}
	}

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

	pub fn set_key_handler(&mut self, f: TabViewKeyHandler) {
		self.key_handler = f;
	}

	/// Forcibly selects the given tab item
	pub fn select_tab(&mut self, tab: &Tab) {
		if let Some(idx) = self.tabs.iter().position(|x| x.id == tab.id)
			&& idx != self.selected
		{
			self.selected = idx;
			self.selection_changed();
		}
	}

	/// This will enumerate each tab depending on the order they are in
	/// Enumerated Tabs will start with (n), n ∈ ℕ
	pub fn enable_tab_enumeration(&mut self) {
		self.enumerate_tabs = true;
	}

	/// Disables the tab enumeration of all tabs
	pub fn disable_tab_enumeration(&mut self) {
		self.enumerate_tabs = false;
	}

	/// Returns the selected [Tab]
	pub fn get_selection(&self) -> Option<&Tab> {
		self.tabs.get(self.selected)
	}

	/// Sets the foreground for the highlighted tab
	pub fn set_highlight_fg_color(&mut self, color: Option<Color>) {
		self.colors.fg_highlight = color;
	}

	/// Sets the background for the highlighted tab
	pub fn set_highlight_bg_color(&mut self, color: Option<Color>) {
		self.colors.bg_highlight = color;
	}

	pub fn select_next(&mut self) {
		if self.selected < self.tabs.len() - 1 {
			self.selected += 1;
			self.selection_changed();
		}
	}

	pub fn select_previous(&mut self) {
		if self.selected > 0 {
			self.selected -= 1;
			self.selection_changed();
		}
	}

	fn selection_changed(&mut self) {
		self.provoke_changed_property(WindowProperty::Children);
		self.provoke_changed_property(WindowProperty::Focus);
		let cb = self.callback.clone();
		cb(self);
	}
}

impl Window for TabView {
	fn children(&mut self, mut builder: SubWindowBuilder) -> SubWindows {
		let base_rect = builder.base_rect();
		if let Some(selection) = self.get_selection() {
			builder
				.add_rect(
					base_rect
						.subrect(0, 1, base_rect.size().x, base_rect.size().y - 1)
						.unwrap(),
				)
				.unwrap();
			builder.add_child(selection.content.clone());
		}
		builder.build().unwrap()
	}

	fn render(&self, canvas: &mut crate::canvas::Canvas) {
		let width = canvas.size().x;
		let mut row = canvas.get_row_variable_width(0).unwrap();
		let selected = self.tabs.get(self.selected);
		let mut size_per_tab = TSize::max(Self::MIN_TAB_WIDTH, width / self.tabs.len() as TSize);
		let tabs_per_page = width / size_per_tab - 1;
		let skip = self.selected / tabs_per_page as usize * tabs_per_page as usize;

		let mut x = 0;
		// Indicate more tabs on the left
		if skip > usize::MIN {
			size_per_tab = TSize::max(Self::MIN_TAB_WIDTH, width / self.tabs.len() as TSize);
			row.add_grapheme(
				Self::ANGLES_LEFT,
				self.base.colors.base_fg,
				self.base.colors.base_bg,
				Style::empty(),
			)
			.ok();
			x += 1;
		}

		for (n, tab) in self.tabs.iter().skip(skip).enumerate() {
			row = row.with_custom_width(x + size_per_tab).unwrap();
			row.skip(x);

			let fg_color;
			let bg_color;

			match selected.unwrap() == tab {
				true => {
					row.set_style(Style::Underline);
					fg_color = self.colors.fg_highlight.or(self.base.colors.base_fg);
					bg_color = self.colors.bg_highlight.or(self.base.colors.base_bg);
				}
				false => {
					fg_color = self.base.colors.base_fg;
					bg_color = self.base.colors.base_bg;
				}
			}

			// Indicate more tabs which cant be shown right now
			if width - x <= size_per_tab * 2 {
				row.add_grapheme(Self::ANGLES_RIGHT, fg_color, bg_color, Style::None)
					.unwrap();
				break;
			}

			if n > 0 {
				row.add_grapheme(Self::TAB_SEPERATOR, fg_color, bg_color, Style::None)
					.ok();
			}

			if self.enumerate_tabs {
				row.add_grapheme(Self::BRACKET_OPEN, fg_color, bg_color, Style::None)
					.ok();
				let tab_n = (skip + n + 1).to_string();
				row.add_string(
					&tab_n,
					fg_color,
					bg_color,
					Style::None,
					Some(VariableWidthGlyphRow::DOT3_REPLACEMENT),
				)
				.ok();
				row.add_grapheme(Self::BRACKET_CLOSE, fg_color, bg_color, Style::None)
					.ok();
				row.add_grapheme(Grapheme::PLACEHOLDER, fg_color, bg_color, Style::None)
					.ok();
			}

			row.add_string(
				&tab.name,
				fg_color,
				bg_color,
				Style::None,
				Some(VariableWidthGlyphRow::DOT3_REPLACEMENT),
			)
			.ok();
			x += size_per_tab;
		}
	}

	fn handle_event(&mut self, event: &mut WindowEvent) {
		(self.key_handler)(self, event);
	}


	fn focus(&self) -> Option<WindowRef> {
		self.get_selection().map(|x| x.content.clone())
	}

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

impl HasWindowUID for TabView {
	fn uid(&self) -> WindowUID {
		self.base.uid
	}
}

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

	fn set_visibility(&mut self, visibility: bool) {
		self.base.visibility = visibility;
		self.provoke_changed_property(WindowProperty::IsVisible);
	}

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

	fn set_height(&mut self, height: super::Size) {
		self.base.size.y = height;
	}

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

	fn set_border(&mut self, border: BorderStyle) {
		self.base.border = border;
		self.provoke_changed_property(WindowProperty::Border);
	}

	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 WidgetColors for TabView {
	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;
	}
}