"""macOS: read the frontmost browser tab URL via AppleScript.

Reads local browser state only (no network call to the target site). Requires
the terminal/app running this to have Automation permission for the browser.
"""
import subprocess
from typing import Optional

# Browsers that expose `URL of active tab of front window` (Chromium family)
# or `URL of front document` (Safari).
_CHROMIUM = ["Google Chrome", "Brave Browser", "Microsoft Edge", "Arc", "Vivaldi", "Chromium"]


def _frontmost_app() -> Optional[str]:
    script = 'tell application "System Events" to get name of first process whose frontmost is true'
    return _osascript(script)


def _osascript(script: str) -> Optional[str]:
    try:
        out = subprocess.run(
            ["osascript", "-e", script],
            capture_output=True, text=True, timeout=5,
        )
        val = out.stdout.strip()
        return val or None
    except Exception:
        return None


def get_active_tab_url() -> Optional[str]:
    app = _frontmost_app()
    if not app:
        return None
    if app in _CHROMIUM:
        return _osascript(f'tell application "{app}" to get URL of active tab of front window')
    if app == "Safari":
        return _osascript('tell application "Safari" to get URL of front document')
    return None