"""Pre-open schema/integrity/count proof; stdlib only, never constructs Store."""
import argparse
import json
from pathlib import Path
import sqlite3


def inspect_readonly(path):
    path = Path(path)
    if not path.is_file() or path.is_symlink():
        raise ValueError('existing nonsymlink private database required')
    with sqlite3.connect(path.resolve().as_uri() + '?mode=ro', uri=True, timeout=5) as db:
        db.execute('PRAGMA query_only=ON')
        db.execute('BEGIN')
        version = db.execute('PRAGMA user_version').fetchone()[0]
        if version != 5:
            raise ValueError('pre-open database is not schema5; refuse migration')
        if db.execute('PRAGMA integrity_check').fetchall() != [('ok',)]:
            raise ValueError('read-only integrity check refused')
        lifecycle = {name: db.execute('SELECT COUNT(*) FROM ' + table).fetchone()[0]
                     for name, table in (('records', 'lifecycle_records'),
                                         ('events', 'lifecycle_events'),
                                         ('pending', 'lifecycle_pending'))}
        result = {'schema_version': version, 'lifecycle': lifecycle,
                  'outbox': dict(db.execute('SELECT state,COUNT(*) FROM outbox GROUP BY state')),
                  'submissions': dict(db.execute('SELECT state,COUNT(*) FROM submissions GROUP BY state')),
                  'integrity': 'ok', 'read_only_pre_open': True, 'store_constructed': False}
        db.rollback()
    return result


if __name__ == '__main__':
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument('--db', type=Path, required=True)
    args = parser.parse_args()
    try:
        print(json.dumps(inspect_readonly(args.db), sort_keys=True))
    except Exception:
        raise SystemExit('read-only schema5/integrity/count gate refused; no Store/admin open') from None