/**
* lesson-html.ts — wire a lesson document up to the classroom runtime at serve time.
*
* Lessons on disk are plain, self-contained HTML: open one in a browser directly and
* it still reads fine. Everything interactive (highlight-to-ask, quiz submission,
* theming) is injected here, so a lesson authored months ago picks up runtime fixes
* without being rewritten.
*/
import { toScriptJson } from "./markdown.js";
export interface LessonRuntimeConfig {
classroom: string;
lesson: string;
classroomTitle: string;
lessonTitle: string;
baseUrl: string;
}
/** The `` additions: shared stylesheet plus the no-flash theme bootstrap. */
function headInjection(): string {
return `
`;
}
function bodyInjection(config: LessonRuntimeConfig): string {
return `
`;
}
/** Insert `snippet` before the first ``, or fall back to prepending it. */
function insertInHead(html: string, snippet: string): string {
const idx = html.search(/<\/head\s*>/i);
if (idx !== -1) return html.slice(0, idx) + snippet + "\n" + html.slice(idx);
// No — try after , else prepend. Lessons are model-authored and a
// stray fragment must still render rather than 500.
const bodyIdx = html.search(/]*>/i);
if (bodyIdx !== -1) {
const end = html.indexOf(">", bodyIdx) + 1;
return html.slice(0, end) + "\n" + snippet + html.slice(end);
}
return snippet + "\n" + html;
}
/** Insert `snippet` before the last ``, or append it. */
function insertBeforeBodyEnd(html: string, snippet: string): string {
const idx = html.toLowerCase().lastIndexOf("");
if (idx !== -1) return html.slice(0, idx) + snippet + "\n" + html.slice(idx);
return html + "\n" + snippet;
}
/**
* Add the classroom runtime to a lesson document.
*
* Idempotent: a lesson that already links the runtime (because the model copied a
* served page back to disk) is returned unchanged rather than double-wired.
*/
export function injectLessonRuntime(html: string, config: LessonRuntimeConfig): string {
if (html.includes('id="cl-config"')) return html;
return insertBeforeBodyEnd(insertInHead(html, headInjection()), bodyInjection(config));
}