import data from "blume:data";

import {
  isInternalPath,
  normalizeBasePath,
  withComposedBasePath,
} from "../../core/base-path.ts";

// Mirrors `markdown/base-links.ts`: a path whose final segment carries a file
// extension is a `public/` asset, served at the site root and never moved
// under `basePath`.
const ASSET_PATH = /\.[a-z0-9]+$/iu;

/** Strip any `#fragment`/`?query` so only the path is extension-tested. */
const pathOf = (url: string): string => url.replace(/[#?].*$/u, "");

/**
 * Rebase a component-emitted `href` the way `markdown/base-links.ts` rebases
 * `[x](/guide)`: a root-relative internal page link gains the composed
 * `deployment.base` + `basePath` prefix, so authors write component links
 * (`<Card href="/guide">`) under the same "as if mounted at root" contract as
 * markdown links. Idempotent per layer (a hand-written `/docs/x` isn't
 * double-prefixed) and inert for external URLs, fragments, relative paths, and
 * asset links.
 */
export const contentHref = (href: string): string =>
  isInternalPath(href) && !ASSET_PATH.test(pathOf(href))
    ? withComposedBasePath(
        normalizeBasePath(import.meta.env.BASE_URL),
        data.config.basePath,
        href
      )
    : href;