---
// One subpage of a section (see src/data/section.ts): its number and title,
// its lede, its picture, its paragraphs, and the navigation out of it.
// Shared by /features/, /architecture/ and /about/'s [slug] routes.
//
// Position in the section's list is the only source of the number and of
// what "previous" and "next" mean, so reordering the data file reorders and
// renumbers the pages with it.
//
// The picture slot takes either an `image` (a file, through astro:assets,
// sized from the import so the page does not reflow) or a `diagram`
// (mermaid, drawn in the browser). A subpage sets one or the other.
//
// The breadcrumb is the section's own title behind an arrow and inside
// square brackets — `[< about]` — not a sentence built around the title:
// any phrasing that reads for one section ("all features") comes out wrong
// for the next ("all about"). Square brackets, deliberately not the
// guillemet-brackets `⟦…⟧`, which mean "unwritten filler" everywhere else
// on this site (see src/data/filler.ts).
import { Image } from "astro:assets";
import Diagram from "./Diagram.astro";
import type { Section, Subpage } from "../data/section";
interface Props {
page: Subpage;
section: Section;
/** The section's URL prefix, with both slashes, e.g. "/features/". */
base: string;
}
const { page, section, base } = Astro.props;
const index = section.pages.findIndex((entry) => entry.slug === page.slug);
const previous = index > 0 ? section.pages[index - 1] : undefined;
const next = index < section.pages.length - 1 ? section.pages[index + 1] : undefined;
---