//! The Askama entry point for `quasi_basics::carousel`.
//!
//! The widget left for `quasi-basics` once three real pages had proved it, and
//! this is the part that stayed: glue between a template's own frame type and
//! the widget's. Called from `partials/carousel.html`, so all three call sites
//! keep the macro they already have.
//!
//! Why the island wraps the region rather than being it: a custom element is
//! what the browser re-upgrades after an htmx swap, which is the whole reason
//! islands are custom elements, and the description emits a plain `<div>`
//! because it has no idea this host prefixes its tags with `mnw-`. The template
//! puts one around the other and both halves stay honest.

use quasi_basics::Frame;
use quasi_router::Node;

/// The markup, for an Askama template to drop in.
#[must_use]
pub fn html(id: &str, items: &[crate::templates::CarouselFrame]) -> String {
    use quasi_axum::Serves as _;

    let node = Node::Region(quasi_basics::carousel(
        id,
        items.iter().map(|frame| {
            let mut built = Frame::new(&frame.image, &frame.alt);
            if let Some((w, h)) = frame.intrinsic {
                built = built.intrinsic(w, h);
            }
            match &frame.caption {
                Some(caption) => built.caption(caption),
                None => built,
            }
        }),
    ));

    // No shell: this is a fragment landing inside a document Askama already
    // built, which is exactly what `fragment` is for.
    quasi_webview::Webview::new().fragment(&node)
}

#[cfg(test)]
mod tests {
    use crate::templates::CarouselFrame;

    /// What the widget guarantees is `quasi-basics`' to test, and it does.
    /// What is MNW's is that this conversion loses nothing on the way through,
    /// because it is the one place a template's frame becomes a widget's.
    #[test]
    fn a_template_frame_arrives_whole() {
        let html = super::html(
            "landing-shots",
            &[
                CarouselFrame {
                    image: "/a.png".into(),
                    alt: "The library, mid-import".into(),
                    caption: Some("Library".into()),
                    intrinsic: Some((5120, 3412)),
                },
                CarouselFrame {
                    image: "/b.png".into(),
                    alt: "A project page".into(),
                    caption: None,
                    intrinsic: None,
                },
            ],
        );

        assert!(html.contains(r#"data-widget="carousel""#), "{html}");
        assert!(html.contains(r#"id="landing-shots""#), "{html}");
        assert!(html.contains(r#"alt="The library, mid-import""#), "{html}");
        assert!(html.contains("Library</figcaption>"), "{html}");
        assert!(html.contains(r#"width="5120" height="3412""#), "{html}");
        assert!(html.contains("/b.png"), "{html}");
    }
}