My Physics Simulator Code Studio

import re as _re

async def process_user_query(query: str) -> str:
    """Generate a standalone browser physics simulator from an experiment brief.

    Args:
        query: Physics scene and the user's experiment requirements.
    """
    brief = query.strip()[:1500]
    if not brief:
        return 'ERROR: Describe a physics experiment first.'
    prompt = (
        'Write ONE complete, standalone HTML document for this physics experiment. '
        'Output ONLY HTML code, starting with <!DOCTYPE html> and ending with </html>. '
        'Use inline CSS and vanilla JavaScript only; no packages, imports, CDNs, images, or network requests. '
        'Include a canvas, requestAnimationFrame animation, a clear physics update using delta time, '
        'and labeled working controls for relevant parameters plus pause and reset. '
        'Keep the simulation responsive and bound time steps for stability. '
        'Keep code compact. Implement the requested physics rather than describing it.\n\n'
        + brief
    )
    answer = str(await agentop_llm.generate(prompt, globals().get('TEMPLATE_SYSTEM_PROMPT', ''))).strip()
    fenced = _re.fullmatch(r'```(?:html)?\s*([\s\S]*?)\s*```', answer, _re.I)
    if fenced:
        answer = fenced.group(1).strip()
    start = _re.search(r'<!doctype\s+html\s*>|<html\b', answer, _re.I)
    end = _re.search(r'</html\s*>', answer, _re.I)
    if start and end and end.end() > start.start():
        answer = answer[start.start():end.end()]
    if not _re.search(r'<html\b', answer, _re.I) or not _re.search(r'<canvas\b', answer, _re.I) or not _re.search(r'<script\b', answer, _re.I) or not _re.search(r'</html\s*>', answer, _re.I):
        return 'ERROR: The model did not return a complete canvas simulator. Try a shorter, more specific experiment brief.'
    return answer