/**
* Patch embedded HTML to display correctly inside an iframe.
*
* Injects CSS that ensures proper sizing and scrolling behavior
* when HTML content is rendered via srcDoc in an iframe.
*/
export function patchHtmlForIframe(html: string): string {
const iframeCss = ``;
// Insert right after or at the start of the document
const headIdx = html.indexOf('');
if (headIdx !== -1) {
const insertPos = headIdx + 6; // after
return html.substring(0, insertPos) + '\n' + iframeCss + html.substring(insertPos);
}
const headWithAttrs = html.indexOf('', headWithAttrs);
if (closeAngle !== -1) {
const insertPos = closeAngle + 1;
return html.substring(0, insertPos) + '\n' + iframeCss + html.substring(insertPos);
}
}
// Fallback: prepend
return iframeCss + html;
}