//! Constellation rendering (docs/06): deterministic layout, SVG sky, PNG card.

pub mod layout;
pub mod svg;

/// OG/badge image: the same renderer at card dimensions (docs/06 — the
/// shareable-badge requirement solved by reuse).
pub fn render_card_png(l: &layout::Layout, title: &str) -> anyhow::Result<Vec<u8>> {
    let svg_str = svg::render_sky(
        l,
        &svg::SvgOptions {
            width: 1200,
            height: 630,
            focus: None,
            card: true,
            title: title.to_string(),
        },
    );
    let mut opts = resvg::usvg::Options::default();
    // Text nodes are dropped without fonts; load the system set once per render
    // (cards are cold-path, cost is acceptable).
    opts.fontdb_mut().load_system_fonts();
    let tree = resvg::usvg::Tree::from_str(&svg_str, &opts)?;
    let mut pixmap = resvg::tiny_skia::Pixmap::new(1200, 630)
        .ok_or_else(|| anyhow::anyhow!("pixmap alloc failed"))?;
    // Letterbox in sky color, not transparency.
    pixmap.fill(resvg::tiny_skia::Color::from_rgba8(5, 6, 15, 255));
    // usvg already fits the 1000×1000 viewBox into the svg's declared
    // 1200×630 canvas (xMidYMid meet), so render with identity.
    resvg::render(&tree, resvg::tiny_skia::Transform::identity(), &mut pixmap.as_mut());
    Ok(pixmap.encode_png()?)
}