//! Showcase de `llimphi-widget-carousel`: 4 páginas de color con dots,
//! flechas, **swipe** (arrastra la página y suelta), **teclado** (←/→) y
//! **auto-play** (avanza sola cada 3 s; cualquier interacción no la detiene,
//! es un demo).
//!
//! Corre con: `cargo run -p llimphi-widget-carousel --example carousel_demo --release`.

use std::sync::Arc;
use std::time::Duration;

use llimphi_ui::llimphi_layout::taffy::{
    prelude::{percent, Size, Style},
    AlignItems, JustifyContent,
};
use llimphi_ui::llimphi_raster::peniko::Color;
use llimphi_ui::{App, Handle, Key, KeyEvent, KeyState, NamedKey, View};
use llimphi_widget_carousel::{
    carousel_view, navigate, CarouselPalette, CarouselSpec, CarouselTransition, CarouselWrap,
};

const N: usize = 4;
/// Cuánto avanza la transición por tick (~60fps → ~180ms de deslizamiento).
const TRANS_STEP: f32 = 0.12;

#[derive(Clone)]
enum Msg {
    Goto(usize),
    Swipe(i32),
    Tick,
    TransTick,
}

struct Model {
    current: usize,
    transition: Option<CarouselTransition>,
}

/// Arranca una transición desde `from` hacia la página actual.
fn begin(m: &mut Model, from: usize) {
    if from != m.current {
        m.transition = Some(CarouselTransition { from, t: 0.0 });
    }
}

struct Showcase;

impl App for Showcase {
    type Model = Model;
    type Msg = Msg;

    fn title() -> &'static str {
        "llimphi · carousel (swipe · ←/→ · auto-play)"
    }

    fn initial_size() -> (u32, u32) {
        (720, 480)
    }

    fn init(handle: &Handle<Msg>) -> Model {
        // Auto-play: un tick cada 3 s que avanza una página.
        handle.spawn_periodic(Duration::from_secs(3), || Msg::Tick);
        // Animación de la transición (~60 fps).
        handle.spawn_periodic(Duration::from_millis(16), || Msg::TransTick);
        Model { current: 0, transition: None }
    }

    fn on_key(_model: &Model, event: &KeyEvent) -> Option<Msg> {
        if event.state != KeyState::Pressed {
            return None;
        }
        match &event.key {
            Key::Named(NamedKey::ArrowLeft) => Some(Msg::Swipe(-1)),
            Key::Named(NamedKey::ArrowRight) => Some(Msg::Swipe(1)),
            _ => None,
        }
    }

    fn update(model: Model, msg: Msg, _: &Handle<Msg>) -> Model {
        let mut m = model;
        match msg {
            Msg::Goto(i) => {
                let from = m.current;
                m.current = i.min(N - 1);
                begin(&mut m, from);
            }
            Msg::Swipe(d) => {
                let from = m.current;
                m.current = navigate(m.current, N, d, CarouselWrap::Wrap);
                begin(&mut m, from);
            }
            Msg::Tick => {
                let from = m.current;
                m.current = navigate(m.current, N, 1, CarouselWrap::Wrap);
                begin(&mut m, from);
            }
            Msg::TransTick => {
                if let Some(mut tr) = m.transition {
                    tr.t += TRANS_STEP;
                    m.transition = if tr.t >= 1.0 { None } else { Some(tr) };
                }
            }
        }
        m
    }

    fn view(model: &Model) -> View<Msg> {
        let colors = [
            Color::from_rgba8(58, 90, 140, 255),
            Color::from_rgba8(140, 72, 82, 255),
            Color::from_rgba8(70, 130, 100, 255),
            Color::from_rgba8(120, 100, 150, 255),
        ];
        let pages: Vec<View<Msg>> = (0..N)
            .map(|i| {
                View::new(Style {
                    size: Size { width: percent(1.0_f32), height: percent(1.0_f32) },
                    align_items: Some(AlignItems::CENTER),
                    justify_content: Some(JustifyContent::CENTER),
                    ..Default::default()
                })
                .fill(colors[i])
                .text(
                    format!("Página {}", i + 1),
                    28.0,
                    Color::from_rgba8(240, 244, 250, 255),
                )
            })
            .collect();

        carousel_view(CarouselSpec {
            pages,
            current: model.current,
            wrap: CarouselWrap::Wrap,
            show_arrows: true,
            palette: CarouselPalette::default(),
            on_change: Arc::new(Msg::Goto),
            on_swipe: Some(Arc::new(Msg::Swipe)),
            transition: model.transition,
        })
    }
}

fn main() {
    llimphi_ui::run::<Showcase>();
}