import sys
from typing import Literal, Optional

from pydantic import BaseModel

from velrim import Client, Document


class Invoice(BaseModel):
    invoice_number: str
    total: float
    currency: Literal["USD", "EUR"]
    po_number: Optional[str] = None


def extract_invoice(path: str):
    with Client() as client:  # reads VELRIM_API_KEY
        result = client.extract(document=Document.from_path(path), schema=Invoice)
    # The default None folds omission and explicit null together in parsed.
    # Keep fields to distinguish their extraction states.
    return result


if __name__ == "__main__":
    if len(sys.argv) != 2:
        raise SystemExit("Usage: python invoice.py invoice.pdf")
    result = extract_invoice(sys.argv[1])
    print({"request_id": result.meta.request_id, "billed_pages": result.meta.billed_pages})