"""News articles router -- paginated, filterable by category."""

from __future__ import annotations

import logging
from typing import Any, Dict, List, Optional

from fastapi import APIRouter, Query

from server.cache import cache
from server.config import settings
from server.services.news_service import get_news, get_news_count

logger = logging.getLogger(__name__)

router = APIRouter(prefix="/api", tags=["news"])


def _cache_key(limit: int, offset: int, category: Optional[str]) -> str:
    return f"news:{limit}:{offset}:{category}"


@router.get("/news")
async def get_news_articles(
    limit: int = Query(default=20, le=50, ge=1),
    offset: int = Query(default=0, ge=0),
    category: Optional[str] = Query(default=None),
) -> Dict[str, Any]:
    """Return a paginated list of news articles.

    Response shape::

        {
            "articles": [ ... ],
            "total":    int,
            "limit":    int,
            "offset":   int,
        }
    """

    key = _cache_key(limit, offset, category)

    # --- cache hit? -----------------------------------------------------------
    cached = await cache.get(key)
    if cached is not None:
        return cached

    # --- cache miss -----------------------------------------------------------
    articles: List[Dict[str, Any]] = []
    total: int = 0

    try:
        articles = await get_news(limit=limit, offset=offset, category=category, max_age_hours=settings.news_max_age_hours)
    except Exception as exc:
        logger.exception("Failed to fetch news articles")
        return {
            "articles": [],
            "total": 0,
            "limit": limit,
            "offset": offset,
            "error": True,
            "message": str(exc),
        }

    try:
        total = await get_news_count(max_age_hours=settings.news_max_age_hours, category=category)
    except Exception as exc:
        logger.exception("Failed to fetch news count")
        # We still have articles -- return them with total = len(articles)
        total = len(articles)

    payload: Dict[str, Any] = {
        "articles": articles,
        "total": total,
        "limit": limit,
        "offset": offset,
    }

    await cache.set(key, payload, settings.news_cache_ttl)
    return payload