"""Shared route utilities: symbol validation and error handling decorator."""

import functools
import logging
from collections.abc import Awaitable, Callable
from typing import ParamSpec, TypeVar

from fastapi import HTTPException

from models import SYMBOL_PATTERN

logger = logging.getLogger(__name__)

P = ParamSpec("P")
R = TypeVar("R")


def validate_symbol(symbol: str) -> str:
    """Validate and normalize a stock symbol."""
    if not SYMBOL_PATTERN.match(symbol):
        raise HTTPException(status_code=400, detail="Invalid symbol format")
    return symbol.upper()


def safe(fn: Callable[P, Awaitable[R]]) -> Callable[P, Awaitable[R]]:
    """Decorator to catch upstream errors and return 502."""
    @functools.wraps(fn)
    async def wrapper(*args: P.args, **kwargs: P.kwargs) -> R:
        try:
            return await fn(*args, **kwargs)
        except HTTPException:
            raise
        except Exception:
            logger.exception("Upstream data error")
            raise HTTPException(
                status_code=502,
                detail="Data provider error. Check server logs.",
            )
    return wrapper  # type: ignore[return-value]