"""Short-lived, cross-worker sales snapshots invalidated by imports and product edits."""
import hashlib
from datetime import date

from services import simple_cache
from services.cache import _data_version_signature


def sales_snapshot(products, build):
    version = _data_version_signature()
    fingerprint = hashlib.sha256(repr(products).encode('utf-8')).hexdigest()
    token = (version, fingerprint, date.today())
    key = 'spot-sales-snapshot-v3'
    try:
        entry = simple_cache.get(key)
    except OSError:
        entry = None
    if entry is not None and entry['token'] == token:
        return entry['result']
    result = build(products)
    # Never publish an old snapshot under a newly imported data version.
    if _data_version_signature() == version:
        try:
            simple_cache.set(key, {'token': token, 'result': result}, ttl=60)
        except OSError:
            pass
    return result