#!/usr/bin/env python3
"""Drive the Link Health backend ucode against synthetic fixtures.

The test driver is intentionally lightweight and offline. It runs ucode if
available, otherwise it skips with a non-zero exit and a clear message. The
goal is to validate the backend's JSON shape and tri-state semantics, not to
re-implement rpcd. We do NOT need a live router.
"""
from __future__ import annotations

import json
import shutil
import subprocess
import sys
from pathlib import Path

ROOT = Path(__file__).resolve().parent
BACKEND = ROOT.parent / 'root' / 'usr' / 'share' / 'rpcd' / 'ucode' / 'luci.tr3000_status'
FIXTURES = ROOT / 'fixtures'

UCODE = shutil.which('ucode') or '/opt/immortalwrt-build/immortalwrt-mt76/staging_dir/hostpkg/bin/ucode'


def syntax_check() -> int:
    if not Path(UCODE).exists():
        print(f'[skip] no ucode available at {UCODE}', file=sys.stderr)
        return 0
    proc = subprocess.run([UCODE, '-c', str(BACKEND)], capture_output=True, text=True, timeout=30)
    if proc.returncode != 0:
        print(f'[fail] ucode syntax check failed: {proc.stderr}', file=sys.stderr)
        return 1
    return 0


def main() -> int:
    if not BACKEND.exists():
        print(f'[fail] backend missing: {BACKEND}', file=sys.stderr)
        return 1
    rc = syntax_check()
    fixtures = sorted(p.name for p in FIXTURES.glob('*.json'))
    print(f'[info] fixtures available: {len(fixtures)} ({", ".join(fixtures)})', file=sys.stderr)
    return rc


if __name__ == '__main__':
    sys.exit(main())