# Python 3. Standard library, no external packages.
# Run on your server with BLOOMHUB_API_KEY in its environment.
import json
import os
import time
from datetime import datetime, timezone
from email.utils import parsedate_to_datetime
from urllib.error import HTTPError, URLError
from urllib.parse import urlencode
from urllib.request import Request, urlopen

BASE = 'https://bloomhub.ru/api/v1'

def retry_delay(header, attempt):
    if header:
        try:
            return max(1, float(header))
        except ValueError:
            try:
                return max(1, (parsedate_to_datetime(header) - datetime.now(timezone.utc)).total_seconds())
            except (ValueError, TypeError):
                pass
    return 0.5 * 2 ** attempt

def api_get(path, query=None):
    if path not in ['/me', '/locations', '/products', '/recipes', '/stock', '/orders']:
        raise ValueError('Use a documented list method in this example.')
    key = os.environ['BLOOMHUB_API_KEY']
    query = {k: v for k, v in (query or {}).items() if v is not None and v != ''}
    url = BASE + path + ('?' + urlencode(query) if query else '')
    for attempt in range(5):
        request = Request(url, headers={'Authorization': 'Bearer ' + key, 'Accept': 'application/json'})
        try:
            with urlopen(request, timeout=15) as response:
                return json.load(response)
        except HTTPError as error:
            if (error.code == 429 or error.code >= 500) and attempt < 4:
                delay = retry_delay(error.headers.get('Retry-After'), attempt)
                error.close()
                time.sleep(delay)
                continue
            try:
                body = json.load(error)
            except (ValueError, OSError):
                body = {}
            finally:
                error.close()
            detail = body.get('error')
            code = detail.get('code') if isinstance(detail, dict) else body.get('code')
            raise RuntimeError('BloomHub HTTP %s: %s' % (error.code, code or 'REQUEST_FAILED')) from None
        except (URLError, TimeoutError):
            if attempt == 4:
                raise
            time.sleep(retry_delay(None, attempt))
    raise RuntimeError('No response after retry limit.')

def api_pages(path, query=None):
    if path not in ['/products', '/recipes', '/stock', '/orders']:
        raise ValueError('This method does not use pagination.')
    for page in range(1, 10001):
        data = api_get(path, {**(query or {}), 'page': page, 'limit': 100})
        if not isinstance(data.get('items'), list) or not isinstance(data.get('pagination', {}).get('hasMore'), bool):
            raise RuntimeError('Unexpected response. Do not advance the synchronization watermark.')
        yield from data['items']
        if not data['pagination']['hasMore']:
            return
    raise RuntimeError('Page limit reached. Do not mark a partial sync complete.')

if __name__ == '__main__':
    path = '/' + os.environ.get('BLOOMHUB_RESOURCE', 'products').lstrip('/')
    params = {'locationId': os.environ.get('BLOOMHUB_LOCATION_ID'), 'updatedAfter': os.environ.get('BLOOMHUB_SINCE')}
    for item in api_pages(path, params):
        print(json.dumps(item, ensure_ascii=False))