#!/usr/bin/env python3
"""Verify the pinned shared contract; never fetch or use a local fallback."""
import importlib.util
from pathlib import Path
import subprocess

URL = 'git@gitee.com:zzmbac/sip-contracts.git'


def git(root, *args):
    return subprocess.check_output(['git', '-C', str(root), *args], text=True, stderr=subprocess.STDOUT).strip()


def check_checkout(root, updating=False):
    if (root / 'contracts/local').exists():
        raise ValueError('contracts/local is a forbidden parallel contract source')
    entry = git(root, 'ls-files', '--stage', '--', 'contracts/schema').split()
    if len(entry) != 4 or entry[0] != '160000' or entry[2] != '0':
        raise ValueError('contracts/schema must be a tracked Git submodule')
    sub = root / 'contracts/schema'
    if not (sub / '.git').exists():
        raise ValueError('contract submodule not initialized; run git submodule update --init --recursive')
    configured = git(root, 'config', '-f', '.gitmodules', '--get', 'submodule.contracts/schema.url')
    if configured != URL or git(sub, 'remote', 'get-url', 'origin') != URL:
        raise ValueError('contract submodule origin must be ' + URL)
    commit = git(sub, 'rev-parse', 'HEAD')
    if commit != entry[1]:
        if not updating:
            raise ValueError('contract HEAD does not match the project pin; stage the verified contracts/schema pointer')
        git(sub, 'merge-base', '--is-ancestor', entry[1], commit)
    if git(sub, 'status', '--porcelain', '--untracked-files=all'):
        raise ValueError('contract submodule has uncommitted changes; verify and commit them in the shared repository')
    return commit


def main():
    root = Path(__file__).resolve().parents[1]
    commit = check_checkout(root)
    checker_path = root / 'contracts/verify.py'
    spec = importlib.util.spec_from_file_location('shared_contract_verify', checker_path)
    checker = importlib.util.module_from_spec(spec)
    spec.loader.exec_module(checker)
    count = checker.verify_bundle(checker_path.parent)
    print(f'shared contract {commit}: {count} JSON files; offline references and historical provenance valid')


if __name__ == '__main__':
    try:
        main()
    except (OSError, ValueError, subprocess.CalledProcessError) as exc:
        raise SystemExit(str(exc)) from exc