"""Cross-platform helper for reading the front browser tab's URL.

This is the one genuinely OS-specific piece. Reading *your own* browser's
current URL is a passive, local operation (no request to the target site), so
it stays within the screen-capture / compliance posture. When it can't return
a URL (common on Windows/Linux), the detector falls back to reading the address
bar visually from a screenshot via the AI.
"""
import sys
from typing import Optional


def get_active_tab_url() -> Optional[str]:
    """Best-effort URL of the frontmost browser tab, or None if unavailable."""
    try:
        if sys.platform == "darwin":
            from . import macos

            return macos.get_active_tab_url()
        if sys.platform.startswith("linux"):
            from . import linux

            return linux.get_active_tab_url()
        if sys.platform in ("win32", "cygwin"):
            from . import windows

            return windows.get_active_tab_url()
    except Exception:
        return None
    return None