import logging
from datetime import datetime
from email.utils import parsedate_to_datetime
from typing import Optional
import feedparser
import httpx

logger = logging.getLogger(__name__)

HEADERS = {
    "User-Agent": "Mozilla/5.0 (compatible; PharmaIntelBot/1.0)"
}


def _parse_date(raw: str) -> Optional[datetime]:
    if not raw:
        return None
    try:
        return parsedate_to_datetime(raw).replace(tzinfo=None)
    except Exception:
        pass
    try:
        return datetime.fromisoformat(raw.replace("Z", "+00:00")).replace(tzinfo=None)
    except Exception:
        return None


async def fetch_rss(url: str, max_items: int = 30) -> list[dict]:
    try:
        async with httpx.AsyncClient(headers=HEADERS, timeout=30, follow_redirects=True) as client:
            resp = await client.get(url)
            resp.raise_for_status()
            text = resp.text
    except Exception as e:
        logger.warning(f"RSS fetch failed {url}: {e}")
        return []

    feed = feedparser.parse(text)
    items = []
    for entry in feed.entries[:max_items]:
        title = entry.get("title", "").strip()
        link = entry.get("link", "").strip()
        if not title or not link:
            continue

        content = (
            entry.get("summary", "")
            or entry.get("content", [{}])[0].get("value", "")
        ).strip()

        published_raw = entry.get("published") or entry.get("updated") or ""
        items.append({
            "title": title,
            "url": link,
            "content": content[:3000],
            "published_at": _parse_date(published_raw),
        })

    logger.info(f"RSS {url}: got {len(items)} items")
    return items


# 默认新闻源（管理页可增删）
DEFAULT_SOURCES = [
    # 中文
    {"name": "国家药监局", "url": "https://www.nmpa.gov.cn/rss/yaopinxinxi.xml", "language": "zh", "category": "药品监管"},
    {"name": "丁香园", "url": "https://www.dxy.cn/bbs/feed.xml", "language": "zh", "category": "临床研究"},
    {"name": "医学界", "url": "https://www.yxj.org.cn/rss.xml", "language": "zh", "category": "行业动态"},
    # 英文
    {"name": "STAT News", "url": "https://www.statnews.com/feed/", "language": "en", "category": "临床研究"},
    {"name": "FiercePharma", "url": "https://www.fiercepharma.com/rss/xml", "language": "en", "category": "行业动态"},
    {"name": "FDA News", "url": "https://www.fda.gov/about-fda/contact-fda/stay-informed/rss-feeds/fda-news-feed/rss.xml", "language": "en", "category": "药品监管"},
]