"""Sequential file/SQLite recovery model. This is not an SQS or S3 emulator."""
import hashlib
import json
import os
from pathlib import Path
import sqlite3
import sys


def initialize(folder):
    folder.mkdir()
    (folder / 'objects').mkdir()
    with sqlite3.connect(folder / 'state.sqlite') as db:
        db.executescript('''
            CREATE TABLE exports (id TEXT PRIMARY KEY, fingerprint TEXT, status TEXT);
            CREATE TABLE publications (export_id TEXT PRIMARY KEY);
            CREATE TABLE acknowledgements (receipt TEXT PRIMARY KEY);
        ''')


def handle(folder, payload, receipt, stop):
    export_id = 'export-cedar-17'  # Fixed synthetic identity, not arbitrary path input.
    fingerprint = hashlib.sha256(payload).hexdigest()
    path = folder / 'objects' / (export_id + '.csv')
    with sqlite3.connect(folder / 'state.sqlite') as db:
        stored = db.execute('SELECT fingerprint, status FROM exports WHERE id=?', (export_id,)).fetchone()
        if stored and stored[0] != fingerprint:
            raise ValueError('export ID reused with different payload')
        db.execute('INSERT OR IGNORE INTO exports VALUES (?, ?, ?)', (export_id, fingerprint, 'pending'))
        db.commit()
        if stored and stored[1] == 'complete' and path.is_file() and path.read_bytes() == payload:
            db.execute('INSERT INTO acknowledgements VALUES (?)', (receipt,))
            db.commit()
            return 'reused'
        if path.exists() and path.read_bytes() != payload:
            raise ValueError('stored object differs from expected bytes')
        if not path.exists():
            path.write_bytes(payload)
        if stop == 'after-object':
            os._exit(23)  # Real process exit; no claim about power loss or fsync.
        with db:
            db.execute('INSERT OR IGNORE INTO publications VALUES (?)', (export_id,))
            db.execute('UPDATE exports SET status=? WHERE id=?', ('complete', export_id))
        if stop == 'after-complete':
            os._exit(24)
        db.execute('INSERT INTO acknowledgements VALUES (?)', (receipt,))
        db.commit()
        return 'published'


if __name__ == '__main__':
    try:
        result = handle(Path(sys.argv[1]), bytes.fromhex(sys.argv[2]), sys.argv[3], sys.argv[4])
        print(json.dumps({'result': result}))
    except ValueError as error:
        print(json.dumps({'error': str(error)}))
        raise SystemExit(2)