//! `cargo run --example showcase`
//!
//! Shows button variants, container with background, a slider, a
//! viewport-relative image, plus the newer additions: a tab strip, a spinner
//! driven by the wall clock, a multiline text edit, and on-demand toast /
//! tooltip overlays.
//! Tab / Shift+Tab cycles keyboard focus. Enter or Space activates the
//! focused button. Esc exits.
//!
//! NOTE: ltk is a Wayland layer-shell toolkit. This example requires a running
//! Wayland compositor (e.g. sway, labwc, or a full desktop session).

use std::sync::Arc;
use std::time::{ Duration, Instant };

use ltk::{
	App, Element, Keysym, ButtonVariant, Length, WidgetId,
	OverlaySpec,
	button, column, row, stack, text, text_edit, spacer, container, slider, scroll,
	spinner, tabs, toast, tooltip, img_widget,
};

const IMG_W: u32 = 64;
const IMG_H: u32 = 64;

fn gradient_rgba() -> Arc<Vec<u8>>
{
	let mut data = Vec::with_capacity( ( IMG_W * IMG_H * 4 ) as usize );
	for y in 0..IMG_H
	{
		for x in 0..IMG_W
		{
			let r = ( 255 * x / IMG_W ) as u8;
			let g = ( 255 * y / IMG_H ) as u8;
			data.extend_from_slice( &[ r, g, 180, 255 ] );
		}
	}
	Arc::new( data )
}

// ── Messages ──────────────────────────────────────────────────────────────────

#[ derive( Clone ) ]
enum Message
{
	Pressed( &'static str ),
	SliderChanged( f32 ),
	SelectTab( usize ),
	NoteChanged( String ),
	ShowToast,
	ToggleTooltip,
	HideToast,
}

// ── App state ─────────────────────────────────────────────────────────────────

struct ShowcaseApp
{
	last_pressed:    String,
	slider_value:    f32,
	tab:             usize,
	note:            String,
	started_at:      Instant,
	toast_until:     Option<Instant>,
	tooltip_visible: bool,
	image:           Arc<Vec<u8>>,
}

impl ShowcaseApp
{
	fn new() -> Self
	{
		Self
		{
			last_pressed:    String::from( "—" ),
			slider_value:    0.5,
			tab:             0,
			note:            String::new(),
			started_at:      Instant::now(),
			toast_until:     None,
			tooltip_visible: false,
			image:           gradient_rgba(),
		}
	}

	const SAVE_BUTTON_ID: WidgetId = WidgetId( "showcase/save" );
}

// ── App trait ─────────────────────────────────────────────────────────────────

impl App for ShowcaseApp
{
	type Message = Message;

	fn view( &self ) -> Element<Message>
	{
		// Pull text colours from the active theme — the runtime
		// background defaults to `palette.bg`, so hard-coded white
		// text would be unreadable in light mode.
		let palette   = ltk::theme_palette();
		let primary   = palette.text_primary;
		let secondary = palette.text_secondary;

		let status = format!( "Last pressed: {}", self.last_pressed );

		// Tabs strip — the active tab just relabels a banner below.
		let tabs_strip: Element<Message> = tabs( [ "Buttons", "Inputs", "Hints" ] )
			.selected( self.tab )
			.on_select( Message::SelectTab )
			.into();
		let tab_banner = format!(
			"Active tab: {}",
			[ "Buttons", "Inputs", "Hints" ][ self.tab.min( 2 ) ],
		);

		let buttons = row::<Message>()
			.spacing( 16.0 )
			.push(
				button( "Primary" )
					.variant( ButtonVariant::Primary )
					.id( Self::SAVE_BUTTON_ID )
					.tooltip( "Hover-dwell tooltip via .tooltip()" )
					.on_press( Message::Pressed( "Primary" ) ),
			)
			.push(
				button( "Secondary" )
					.variant( ButtonVariant::Secondary )
					.tooltip( "Secondary action" )
					.on_press( Message::Pressed( "Secondary" ) ),
			)
			.push(
				button( "Tertiary" )
					.variant( ButtonVariant::Tertiary )
					.tooltip( "Tertiary action" )
					.on_press( Message::Pressed( "Tertiary" ) ),
			);

		let card = container::<Message>(
			column::<Message>()
				.spacing( 8.0 )
				.push( text( "container() demo" ).size( 14.0 ).color( primary ) )
				.push(
					text( "Background color + padding + corner radius" )
						.size( 12.0 )
						.color( secondary ),
				),
		)
		.background( palette.surface_alt )
		.radius( 12.0 )
		.padding( 16.0 );

		// Viewport-relative image: 30 % of the surface width by 10 % of its
		// height, so it rescales with the window instead of staying fixed.
		//
		// The second image uses the orientation-aware helpers: `short_side`
		// sizes it along the screen's short side (width in portrait, height
		// in landscape) while `orient` gives that side a different proportion
		// per orientation — 40 % of the width in portrait, 8 % of the height
		// in landscape — with the other axis following the source aspect.
		let banner = column::<Message>()
			.spacing( 4.0 )
			.push( text( "img_widget().size( vw 30, vh 10 )" ).size( 12.0 ).color( secondary ) )
			.push( img_widget( self.image.clone(), IMG_W, IMG_H ).size( Length::vw( 30.0 ), Length::vh( 10.0 ) ) )
			.push(
				text( "short_side( orient( 40 %w, 8 %h ) ) — resize / rotate to compare" )
					.size( Length::orient( 3.0, 2.2 ).clamp( 11.0, 16.0 ) )
					.color( secondary )
			)
			.push( img_widget( self.image.clone(), IMG_W, IMG_H ).short_side( Length::orient( 40.0, 8.0 ) ) );

		let vol_label = format!( "Volume: {:.0}%", self.slider_value * 100.0 );

		// Spinner — phase comes straight from the wall clock so the arc
		// completes one revolution per second.
		let phase = self.started_at.elapsed().as_secs_f32();
		let spin_row: Element<Message> = row::<Message>()
			.spacing( 12.0 )
			.push( spinner().phase( phase ) )
			.push( text( "Working…" ).size( 14.0 ).color( primary ) )
			.into();

		// Multiline text area.
		let textarea = text_edit( "Type a note (multi-line)", &self.note )
			.multiline( true )
			.rows( 3 )
			.on_change( Message::NoteChanged );

		// Buttons that exercise the overlay-returning widgets.
		let overlay_row = row::<Message>()
			.spacing( 12.0 )
			.push( button( "Show toast" ).on_press( Message::ShowToast ) )
			.push(
				button( if self.tooltip_visible { "Hide tooltip" } else { "Show tooltip" } )
					.on_press( Message::ToggleTooltip )
			);

		let body = column::<Message>()
			.padding( 32.0 )
			.spacing( 16.0 )
			.push( text( "ltk showcase" ).size( 24.0 ).color( primary ).align_center() )
			.push( text( status ).size( 14.0 ).color( secondary ).align_center() )
			.push( tabs_strip )
			.push( text( tab_banner ).size( 12.0 ).color( secondary ).align_center() )
			.push( spacer() )
			.push( buttons )
			.push( card )
			.push( banner )
			.push( text( vol_label ).size( 13.0 ).color( secondary ) )
			.push( slider( self.slider_value ).on_change( Message::SliderChanged ) )
			.push( spin_row )
			.push( textarea )
			.push( overlay_row )
			.push( spacer() )
			.push(
				text( "Tab = focus next  ·  Enter / Space = press  ·  Esc = quit" )
					.size( 12.0 )
					.color( secondary )
					.align_center(),
			);

		// Toast lives inside the main view (works on every
		// compositor — no `wlr-layer-shell` required). The Tooltip
		// stays in `overlays()` because xdg-popup is universal.
		let mut s = stack::<Message>().push( scroll( body ) );
		if self.toast_until.is_some()
		{
			s = s.push( toast::<Message>( "Saved" ).view() );
		}
		s.into()
	}

	fn update( &mut self, msg: Message )
	{
		match msg
		{
			Message::Pressed( name )       => self.last_pressed = name.to_string(),
			Message::SliderChanged( val )  => self.slider_value = val,
			Message::SelectTab( i )        => self.tab = i,
			Message::NoteChanged( s )      => self.note = s,
			Message::ShowToast             =>
			{
				self.toast_until = Some( Instant::now() + Duration::from_secs( 2 ) );
			}
			Message::HideToast             => self.toast_until = None,
			Message::ToggleTooltip         => self.tooltip_visible = !self.tooltip_visible,
		}
	}

	fn overlays( &self ) -> Vec<OverlaySpec<Message>>
	{
		// Tooltip is an xdg-popup → works on any xdg-shell compositor.
		// Toast is rendered inline in `view()` (see the Stack at the
		// bottom of the function) so it does not depend on
		// `wlr-layer-shell` either.
		if self.tooltip_visible
		{
			vec![ tooltip::<Message>( "Saves the document and closes the dialog", Self::SAVE_BUTTON_ID ).overlay() ]
		} else {
			vec![]
		}
	}

	fn on_key( &mut self, keysym: Keysym ) -> Option<Message>
	{
		if keysym == Keysym::Escape
		{
			std::process::exit( 0 );
		}
		None
	}

	// Keep redrawing while the spinner is on screen and while a toast
	// is pending so its expiry timestamp is checked every frame.
	fn is_animating( &self ) -> bool { true }

	// Auto-clear an expired toast.
	fn poll_interval( &self ) -> Option<Duration>
	{
		Some( Duration::from_millis( 250 ) )
	}

	fn poll_external( &mut self ) -> Vec<Message>
	{
		match self.toast_until
		{
			Some( deadline ) if Instant::now() >= deadline => vec![ Message::HideToast ],
			_                                              => vec![],
		}
	}
}

// ── Entry point ───────────────────────────────────────────────────────────────

fn main()
{
	ltk::run( ShowcaseApp::new() );
}
