"""抓取并整理国际 / 国内 AI 时讯 RSS。"""

from __future__ import annotations

import logging
import re
import time
import html
import xml.etree.ElementTree as ET
from concurrent.futures import ThreadPoolExecutor, as_completed
from datetime import datetime, timezone, timedelta
from email.utils import parsedate_to_datetime
from typing import Any
from urllib.parse import parse_qs, urlencode, urlparse, urlunparse

import certifi
import httpx

from daily.config import env, env_int, news_summary_limit
from daily.news.content_filter import filter_news_items
from daily.news.feeds import NEWS_CATEGORIES, NewsCategory, NewsFeed
from daily.news.feeds_cn import CN_AI_TITLE_KEYWORDS, CN_NEWS_CATEGORIES

logger = logging.getLogger(__name__)

USER_AGENT = "Mozilla/5.0 (compatible; daily-robots/1.0; +https://skills.sh)"
BROWSER_USER_AGENT = (
    "Mozilla/5.0 (Windows NT 10.0; Win64; x64) "
    "AppleWebKit/537.36 (KHTML, like Gecko) "
    "Chrome/131.0.0.0 Safari/537.36"
)
STRIP_HTML = re.compile(r"<[^>]+>")
WS = re.compile(r"\s+")

ATOM_NS = {"a": "http://www.w3.org/2005/Atom"}
RSS_NS = {"r": "http://purl.org/rss/1.0/modules/content/"}


def _enabled() -> bool:
    raw = (env("DAILY_AI_NEWS") or "1").strip().lower()
    return raw not in {"0", "false", "no", "off"}


def _cn_enabled() -> bool:
    raw = (env("DAILY_CN_AI_NEWS") or "1").strip().lower()
    return raw not in {"0", "false", "no", "off"}


def _hours_window() -> int:
    return max(1, env_int("DAILY_AI_NEWS_HOURS", 72))


def _per_feed_limit() -> int:
    return max(1, env_int("DAILY_AI_NEWS_PER_FEED", 3))


def _per_category_limit() -> int:
    return max(1, env_int("DAILY_AI_NEWS_PER_CATEGORY", 5))


def _wecom_limit() -> int:
    return max(1, env_int("DAILY_WECOM_AI_NEWS", 10))


def _wecom_cn_limit() -> int:
    return max(1, env_int("DAILY_WECOM_CN_AI_NEWS", 8))


def _matches_cn_ai_title(title: str) -> bool:
    text = title.strip()
    if not text:
        return False
    lower = text.lower()
    for keyword in CN_AI_TITLE_KEYWORDS:
        if keyword.lower() in lower:
            return True
    return False


def _filter_ai_entries(entries: list[dict[str, Any]], *, ai_filter: bool) -> list[dict[str, Any]]:
    if not ai_filter:
        return entries
    return [item for item in entries if _matches_cn_ai_title(item.get("title", ""))]


def _now_utc() -> datetime:
    return datetime.now(timezone.utc)


def _parse_datetime(value: str | None) -> datetime | None:
    if not value:
        return None
    text = value.strip()
    if not text:
        return None
    try:
        dt = parsedate_to_datetime(text)
        if dt.tzinfo is None:
            dt = dt.replace(tzinfo=timezone.utc)
        return dt.astimezone(timezone.utc)
    except (TypeError, ValueError, OverflowError):
        pass
    for fmt in (
        "%Y-%m-%dT%H:%M:%SZ",
        "%Y-%m-%dT%H:%M:%S%z",
        "%Y-%m-%d",
    ):
        try:
            dt = datetime.strptime(text[: len(fmt.replace("%z", "+0000"))], fmt.replace("%z", ""))
            if dt.tzinfo is None:
                dt = dt.replace(tzinfo=timezone.utc)
            return dt.astimezone(timezone.utc)
        except ValueError:
            continue
    return None


def _clean_text(text: str | None, limit: int = 200) -> str:
    if not text:
        return ""
    plain = STRIP_HTML.sub(" ", html.unescape(text))
    plain = WS.sub(" ", plain).strip()
    if limit <= 0 or len(plain) <= limit:
        return plain
    return plain[: limit - 3] + "..."


def _normalize_link(link: str) -> str:
    parsed = urlparse(link.strip())
    query = parse_qs(parsed.query, keep_blank_values=False)
    for key in list(query.keys()):
        if key.lower().startswith("utm_") or key.lower() in {"ref", "source"}:
            query.pop(key, None)
    clean_query = urlencode({k: v[0] for k, v in query.items() if v}, doseq=False)
    return urlunparse((parsed.scheme, parsed.netloc, parsed.path.rstrip("/"), "", clean_query, ""))


def _normalize_title(title: str) -> str:
    return WS.sub(" ", title.strip().lower())


def _entry_datetime(entry: dict[str, Any]) -> datetime | None:
    for key in ("published", "updated"):
        dt = _parse_datetime(entry.get(key))
        if dt:
            return dt
    return None


def _parse_atom(content: str, feed_name: str, category: NewsCategory) -> list[dict[str, Any]]:
    items: list[dict[str, Any]] = []
    try:
        root = ET.fromstring(content)
    except ET.ParseError:
        return items

    for entry in root.findall("a:entry", ATOM_NS):
        title_el = entry.find("a:title", ATOM_NS)
        link_el = entry.find("a:link", ATOM_NS)
        summary_el = entry.find("a:summary", ATOM_NS) or entry.find("a:content", ATOM_NS)
        updated_el = entry.find("a:updated", ATOM_NS) or entry.find("a:published", ATOM_NS)
        title = title_el.text.strip() if title_el is not None and title_el.text else ""
        link = ""
        if link_el is not None:
            link = link_el.get("href") or (link_el.text or "").strip()
        if not title or not link:
            continue
        items.append(
            {
                "title": title,
                "link": link,
                "summary": _clean_text(summary_el.text if summary_el is not None else ""),
                "published": updated_el.text.strip() if updated_el is not None and updated_el.text else "",
                "source_name": feed_name,
                "category_id": category.id,
                "category_name": category.name,
                "category_icon": category.icon,
            }
        )
    return items


def _parse_rss(content: str, feed_name: str, category: NewsCategory) -> list[dict[str, Any]]:
    items: list[dict[str, Any]] = []
    try:
        root = ET.fromstring(content)
    except ET.ParseError:
        return items

    channel = root.find("channel")
    if channel is None:
        return items

    for item in channel.findall("item"):
        title_el = item.find("title")
        link_el = item.find("link")
        desc_el = item.find("description")
        pub_el = item.find("pubDate")
        title = title_el.text.strip() if title_el is not None and title_el.text else ""
        link = link_el.text.strip() if link_el is not None and link_el.text else ""
        if not title or not link:
            continue
        items.append(
            {
                "title": title,
                "link": link,
                "summary": _clean_text(desc_el.text if desc_el is not None else ""),
                "published": pub_el.text.strip() if pub_el is not None and pub_el.text else "",
                "source_name": feed_name,
                "category_id": category.id,
                "category_name": category.name,
                "category_icon": category.icon,
            }
        )
    return items


def _parse_feed(content: str, feed_name: str, category: NewsCategory) -> list[dict[str, Any]]:
    text = content.lstrip("\ufeff").strip()
    if not text:
        return []
    if text.startswith("<rss") or "<channel>" in text[:500]:
        return _parse_rss(text, feed_name, category)
    if text.startswith("<feed") or "<entry>" in text[:500]:
        return _parse_atom(text, feed_name, category)
    if "<item>" in text[:2000]:
        return _parse_rss(text, feed_name, category)
    return _parse_atom(text, feed_name, category)


def _is_reddit_url(url: str) -> bool:
    host = urlparse(url).netloc.lower()
    return host.endswith("reddit.com")


def _reddit_auth_params() -> dict[str, str]:
    user = (env("REDDIT_RSS_USER") or "").strip()
    feed = (env("REDDIT_RSS_FEED") or "").strip()
    if user and feed:
        return {"user": user, "feed": feed}
    return {}


def _with_query_params(url: str, extra: dict[str, str]) -> str:
    if not extra:
        return url
    parsed = urlparse(url)
    query = parse_qs(parsed.query, keep_blank_values=True)
    for key, value in extra.items():
        if value and key not in query:
            query[key] = [value]
    clean_query = urlencode({k: v[0] for k, v in query.items() if v and v[0]}, doseq=False)
    return urlunparse((parsed.scheme, parsed.netloc, parsed.path, "", clean_query, ""))


def _reddit_old_url(url: str) -> str:
    parsed = urlparse(url)
    host = parsed.netloc.lower()
    if host.startswith("old."):
        return url
    if host in {"www.reddit.com", "reddit.com"}:
        return urlunparse((parsed.scheme, "old.reddit.com", parsed.path, "", parsed.query, ""))
    return url


def _request_headers(base: dict[str, str], url: str) -> dict[str, str]:
    if not _is_reddit_url(url):
        return base
    return {
        **base,
        "User-Agent": BROWSER_USER_AGENT,
        "Accept-Language": "en-US,en;q=0.9",
    }


def _reddit_fetch_urls(feed_url: str) -> list[str]:
    primary = _with_query_params(feed_url, _reddit_auth_params())
    if not _is_reddit_url(primary):
        return [primary]
    fallback = _reddit_old_url(primary)
    if fallback == primary:
        return [primary]
    return [primary, fallback]


def _fetch_one(
    client: httpx.Client,
    category: NewsCategory,
    feed: NewsFeed,
) -> tuple[list[dict[str, Any]], bool]:
    last_exc: Exception | None = None
    for url in _reddit_fetch_urls(feed.url):
        try:
            headers = _request_headers(dict(client.headers), url)
            resp = client.get(url, headers=headers)
            resp.raise_for_status()
            entries = _parse_feed(resp.text, feed.name, category)
            return _filter_ai_entries(entries, ai_filter=feed.ai_filter), True
        except Exception as exc:
            last_exc = exc
            continue
    logger.warning("RSS fetch failed [%s] %s: %s", feed.name, feed.url, last_exc)
    return [], False


def _dedupe_items(items: list[dict[str, Any]]) -> list[dict[str, Any]]:
    seen_links: set[str] = set()
    seen_titles: set[str] = set()
    result: list[dict[str, Any]] = []
    for item in items:
        link_key = _normalize_link(item["link"])
        title_key = _normalize_title(item["title"])
        if link_key in seen_links or title_key in seen_titles:
            continue
        seen_links.add(link_key)
        seen_titles.add(title_key)
        result.append(item)
    return result


def _within_window(item: dict[str, Any], cutoff: datetime) -> bool:
    dt = _entry_datetime(item)
    if dt is None:
        return True
    return dt >= cutoff


def _sort_key(item: dict[str, Any]) -> tuple[int, datetime]:
    dt = _entry_datetime(item)
    if dt is None:
        return (1, datetime.min.replace(tzinfo=timezone.utc))
    return (0, dt)


def _fetch_news(categories: tuple[NewsCategory, ...]) -> dict[str, Any]:
    hours = _hours_window()
    per_feed = _per_feed_limit()
    per_category = _per_category_limit()
    cutoff = _now_utc() - timedelta(hours=hours)

    headers = {"User-Agent": USER_AGENT, "Accept": "application/rss+xml, application/atom+xml, application/xml, text/xml, */*"}
    tasks: list[tuple[NewsCategory, NewsFeed]] = []
    for category in categories:
        for feed in category.feeds:
            tasks.append((category, feed))

    raw_by_category: dict[str, list[dict[str, Any]]] = {c.id: [] for c in categories}
    stats: dict[str, Any] = {
        "feeds_total": len(tasks),
        "feeds_ok": 0,
        "items_raw": 0,
        "feeds_failed": [],
        "content_filtered": 0,
    }

    with httpx.Client(timeout=15.0, verify=certifi.where(), follow_redirects=True, headers=headers) as client:
        fast_tasks = [t for t in tasks if not t[1].slow]
        slow_tasks = [t for t in tasks if t[1].slow]

        with ThreadPoolExecutor(max_workers=8) as pool:
            futures = {
                pool.submit(_fetch_one, client, cat, feed): (cat.id, feed.name)
                for cat, feed in fast_tasks
            }
            for future in as_completed(futures):
                cat_id, feed_name = futures[future]
                try:
                    entries, ok = future.result()
                except Exception as exc:
                    logger.warning("RSS 任务异常 [%s]: %s", feed_name, exc)
                    stats["feeds_failed"].append(feed_name)
                    continue
                if ok:
                    stats["feeds_ok"] += 1
                else:
                    stats["feeds_failed"].append(feed_name)
                stats["items_raw"] += len(entries)
                raw_by_category[cat_id].extend(entries[:per_feed])

        for cat, feed in slow_tasks:
            entries, ok = _fetch_one(client, cat, feed)
            if ok:
                stats["feeds_ok"] += 1
            else:
                stats["feeds_failed"].append(feed.name)
            stats["items_raw"] += len(entries)
            raw_by_category[cat.id].extend(entries[:per_feed])
            if _is_reddit_url(feed.url):
                time.sleep(2.0)
            else:
                time.sleep(1.0)

    categories_out: list[dict[str, Any]] = []
    flat: list[dict[str, Any]] = []

    for category in categories:
        items = raw_by_category[category.id]
        items = [i for i in items if _within_window(i, cutoff)]
        items, filtered_count = filter_news_items(items)
        if filtered_count:
            stats["content_filtered"] = stats.get("content_filtered", 0) + filtered_count
        items.sort(key=_sort_key, reverse=True)
        items = _dedupe_items(items)[:per_category]
        for item in items:
            dt = _entry_datetime(item)
            item["published_fmt"] = dt.astimezone(timezone(timedelta(hours=8))).strftime("%m-%d %H:%M") if dt else ""
        if items:
            categories_out.append(
                {
                    "id": category.id,
                    "name": category.name,
                    "icon": category.icon,
                    "items": items,
                }
            )
            flat.extend(items)

    flat.sort(key=_sort_key, reverse=True)
    flat = _dedupe_items(flat)

    return {
        "enabled": True,
        "hours": hours,
        "categories": categories_out,
        "flat": flat,
        "stats": stats,
    }


def fetch_ai_news() -> dict[str, Any]:
    """按类别抓取国际 AI 时讯，返回 {enabled, hours, categories, flat, stats}。"""
    if not _enabled():
        return {"enabled": False, "categories": [], "flat": [], "stats": {}}
    return _fetch_news(NEWS_CATEGORIES)


def fetch_cn_ai_news() -> dict[str, Any]:
    """按类别抓取国内 AI 时讯，返回 {enabled, hours, categories, flat, stats}。"""
    if not _cn_enabled():
        return {"enabled": False, "categories": [], "flat": [], "stats": {}}
    return _fetch_news(CN_NEWS_CATEGORIES)


def format_news_section(news: dict[str, Any], *, section_no: int, wecom_limit: int | None = None) -> list[str]:
    return _format_news_section(
        news,
        section_no=section_no,
        title="国际 AI 时讯",
        disabled_hint="AI 时讯已关闭（`DAILY_AI_NEWS=0`）。",
        wecom_limit=wecom_limit,
    )


def format_cn_news_section(news: dict[str, Any], *, section_no: int, wecom_limit: int | None = None) -> list[str]:
    return _format_news_section(
        news,
        section_no=section_no,
        title="国内 AI 时讯",
        disabled_hint="国内 AI 时讯已关闭（`DAILY_CN_AI_NEWS=0`）。",
        wecom_limit=wecom_limit,
    )


def _format_news_section(
    news: dict[str, Any],
    *,
    section_no: int,
    title: str,
    disabled_hint: str,
    wecom_limit: int | None = None,
) -> list[str]:
    if not news.get("enabled"):
        return ["---", "", f"## {section_no}、{title}", "", f"*{disabled_hint}*", ""]

    categories = news.get("categories") or []
    hours = news.get("hours", 72)
    lines = [
        "---",
        "",
        f"## {section_no}、{title}",
        "",
        f"> 近 **{hours}h** · {news.get('stats', {}).get('feeds_ok', 0)}/{news.get('stats', {}).get('feeds_total', 0)} 源可用",
        "",
    ]
    failed = news.get("stats", {}).get("feeds_failed") or []
    if failed:
        preview = "、".join(failed[:5])
        suffix = "…" if len(failed) > 5 else ""
        lines.append(f"> ⚠️ {len(failed)} 个源抓取失败：{preview}{suffix}")
        lines.append("")

    if not categories:
        lines.append("*暂无可用条目（网络/RSS 源异常或时间窗口内无更新）。*")
        lines.append("")
        return lines

    if wecom_limit is not None:
        flat = (news.get("flat") or [])[:wecom_limit]
        for i, item in enumerate(flat, 1):
            pub = f" · {item['published_fmt']}" if item.get("published_fmt") else ""
            lines.append(
                f"{i}. [{item['title']}]({item['link']}) · `{item['source_name']}`{pub}"
            )
        lines.append("")
        return lines

    for cat in categories:
        lines.append(f"### {cat['icon']} {cat['name']}")
        lines.append("")
        for i, item in enumerate(cat["items"], 1):
            pub = f" · {item['published_fmt']}" if item.get("published_fmt") else ""
            lines.append(f"{i}. **[{item['title']}]({item['link']})** · `{item['source_name']}`{pub}")
            summary = item.get("summary", "")
            if summary:
                lines.append(f"   - {_clean_text(summary, news_summary_limit())}")
        lines.append("")

    return lines


def _sorted_flat(news: dict[str, Any]) -> list[dict[str, Any]]:
    flat = list(news.get("flat") or [])
    flat.sort(
        key=lambda item: (float(item.get("score") or 0), _sort_key(item)[1]),
        reverse=True,
    )
    return flat


def prepare_wecom_news_items(news: dict[str, Any], *, limit: int | None = None) -> list[dict[str, Any]]:
    if not news.get("enabled"):
        return []
    pick_limit = limit or _wecom_limit()
    flat = _sorted_flat(news)
    preferred = ("media", "newsletter", "official", "community", "research", "developer")
    picked: list[dict[str, Any]] = []
    seen: set[str] = set()
    for cat in preferred:
        for item in flat:
            link = _normalize_link(item.get("link", ""))
            if item.get("category_id") != cat or link in seen:
                continue
            picked.append(item)
            seen.add(link)
            if len(picked) >= pick_limit:
                break
        if len(picked) >= pick_limit:
            break
    items: list[dict[str, Any]] = []
    for item in picked[:pick_limit]:
        items.append(
            {
                "title": item.get("title", "?"),
                "link": item.get("link", ""),
                "source_name": item.get("source_name", "?"),
                "published_fmt": item.get("published_fmt", ""),
                "desc_short": _clean_text(item.get("summary", ""), 36),
                "score": item.get("score"),
            }
        )
    return items


def prepare_wecom_cn_news_items(news: dict[str, Any], *, limit: int | None = None) -> list[dict[str, Any]]:
    if not news.get("enabled"):
        return []
    pick_limit = limit or _wecom_cn_limit()
    flat = _sorted_flat(news)
    preferred = ("media", "tech", "dev")
    picked: list[dict[str, Any]] = []
    seen_links: set[str] = set()
    seen_sources: set[str] = set()

    for cat in preferred:
        for item in flat:
            link = _normalize_link(item.get("link", ""))
            source = item.get("source_name", "?")
            if item.get("category_id") != cat or not link or link in seen_links or source in seen_sources:
                continue
            picked.append(item)
            seen_links.add(link)
            seen_sources.add(source)
            if len(picked) >= pick_limit:
                break
        if len(picked) >= pick_limit:
            break

    if len(picked) < pick_limit:
        for item in flat:
            link = _normalize_link(item.get("link", ""))
            if not link or link in seen_links:
                continue
            picked.append(item)
            seen_links.add(link)
            if len(picked) >= pick_limit:
                break

    items: list[dict[str, Any]] = []
    for item in picked[:pick_limit]:
        items.append(
            {
                "title": item.get("title", "?"),
                "link": item.get("link", ""),
                "source_name": item.get("source_name", "?"),
                "published_fmt": item.get("published_fmt", ""),
                "desc_short": _clean_text(item.get("summary", ""), 36),
                "score": item.get("score"),
            }
        )
    return items