from abc import ABC, abstractmethod

SYSTEM_PROMPT = (
    "You are a financial document analysis assistant. "
    "Given the text extracted from a PDF document, return ONLY a JSON object "
    "with no markdown, no code fences, and no explanation."
)

USER_PROMPT_TEMPLATE = """Analyze the following document text and return a JSON object with exactly these keys:
document_type (one of: invoice, bill, receipt, order, expense, revenue, unknown),
total_amount (string or null),
currency (string or null),
vendor_name (string or null),
customer_name (string or null),
billing_address (string or null),
customer_address (string or null),
invoice_number (string or null),
invoice_date (string or null),
due_date (string or null),
tags (array of strings),
line_items (array of objects, each with keys: description, amount).

Document text:
{text}"""


class AIProvider(ABC):
    @abstractmethod
    async def classify_document(self, text: str) -> dict:
        """Return structured extraction dict from document text."""
        ...