"""BARMAN first purchase: standard-library only. Run: python first_purchase.py.

Read the catalog first, explicitly accept a EUR 0 order, and save its private
receipt. Retry by running again with the same --key and buyer details.
"""
import argparse
import json
import os
from pathlib import Path
import urllib.error
import urllib.request
import uuid

BASE = 'https://barman-ai-agent.onrender.com'


def main():
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument('--name', default='My Agent')
    parser.add_argument('--reference', default='urn:agent:my-agent')
    parser.add_argument('--key', default=None)
    parser.add_argument('--source', default='developer-quickstart')
    args = parser.parse_args()
    key = args.key or str(uuid.uuid4())
    print('Order idempotency key:', key, '(reuse it for retries)')
    with urllib.request.urlopen(BASE + '/v1/catalog', timeout=30) as response:
        checkout = json.load(response)['checkout']
    print('Stripe mode:', checkout['mode'], '| Total: EUR 0.00 | No card or email')
    if not checkout['ready']:
        raise SystemExit('Checkout is currently unavailable.')
    if input('Type ACCEPT to order one virtual beer at EUR 0.00: ').strip() != 'ACCEPT':
        raise SystemExit('No order submitted.')
    payload = {'agent_name': args.name, 'agent_reference': args.reference, 'accept': True,
               'idempotency_key': key, 'source': args.source}
    request = urllib.request.Request(BASE + '/v1/checkout', data=json.dumps(payload).encode(),
                                    headers={'Content-Type': 'application/json'})
    try:
        with urllib.request.urlopen(request, timeout=30) as response:
            receipt = json.load(response)
    except (urllib.error.URLError, TimeoutError):
        raise SystemExit('Request pending or unavailable. Retry with the same --key and buyer details.') from None
    destination = Path(receipt['order_id'] + '.private.json')
    descriptor = os.open(destination, os.O_WRONLY | os.O_CREAT | os.O_EXCL, 0o600)
    with os.fdopen(descriptor, 'w', encoding='utf-8') as file:
        json.dump(receipt, file, indent=2)
    print('Status:', receipt['status'], '| Stripe invoice:', receipt['provider_reference'])
    print('Private receipt saved to', destination, '— keep it private.')


if __name__ == '__main__':
    main()