"""Shared contract for query executors."""

from abc import ABC, abstractmethod
from dataclasses import dataclass, field

from sqlalchemy.ext.asyncio import AsyncSession

from src.rag.base import RetrievalResult


@dataclass
class QueryResult:
    source_type: str        # "database" or "document"
    source_id: str          # database_client_id or document_id
    table_or_file: str
    columns: list[str]
    rows: list[dict]
    row_count: int
    metadata: dict = field(default_factory=dict)
    # metadata should include "column_types": {"col_name": "dtype"} when available


class BaseExecutor(ABC):
    @abstractmethod
    async def execute(
        self,
        results: list[RetrievalResult],
        user_id: str,
        db: AsyncSession,
        question: str,
        limit: int = 100,
    ) -> list[QueryResult]: ...