"""BaseExecutor + QueryResult — uniform return shape across DB and tabular paths."""

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

from ..ir.models import QueryIR


@dataclass
class QueryResult:
    source_id: str
    backend: str  # "sql" | "tabular"
    columns: list[str] = field(default_factory=list)
    rows: list[dict[str, Any]] = field(default_factory=list)
    row_count: int = 0
    truncated: bool = False
    elapsed_ms: int = 0
    error: str | None = None
    table_id: str = ""
    table_name: str = ""
    source_name: str = ""
    # The executed query string (compiled SQL for db, rendered pandas chain for
    # tabular), surfaced to traceability. None on error/unset paths. KM-691.
    query: str | None = None


class BaseExecutor(ABC):
    """Subclasses: DbExecutor, TabularExecutor."""

    @abstractmethod
    async def run(self, ir: QueryIR) -> QueryResult:
        ...