"""skills.sh feed.json 拉取、缓存与榜单数据。"""

from __future__ import annotations

import json
import logging
import time
from pathlib import Path
from typing import Any, Literal

import certifi
import httpx

logger = logging.getLogger(__name__)

ROOT = Path(__file__).resolve().parent.parent
FEED_URLS = [
    "https://cdn.jsdelivr.net/gh/NeverSight/skills.sh_feed@main/data/feed.json",
    "https://raw.githubusercontent.com/NeverSight/skills.sh_feed/main/data/feed.json",
]
CACHE_TTL_SECONDS = 600
CACHE_DIR = ROOT / ".cache"
CACHE_FILE = CACHE_DIR / "skills-feed.json"
USER_AGENT = "Mozilla/5.0 (compatible; daily-robots/1.0; +https://skills.sh)"

_cache: dict[str, Any] = {"data": None, "fetched_at": 0.0}

Board = Literal["trending", "hot", "all"]

BOARD_FEED_KEYS = {
    "trending": "topTrending",
    "hot": "topHot",
    "all": "topAllTime",
}


def _fetch_json(url: str) -> dict[str, Any]:
    headers = {"User-Agent": USER_AGENT, "Accept": "application/json"}
    with httpx.Client(
        timeout=httpx.Timeout(20.0, connect=10.0),
        verify=certifi.where(),
        follow_redirects=True,
    ) as client:
        resp = client.get(url, headers=headers)
        resp.raise_for_status()
        return resp.json()


def _load_disk_cache() -> dict[str, Any] | None:
    if not CACHE_FILE.exists():
        return None
    try:
        return json.loads(CACHE_FILE.read_text(encoding="utf-8"))
    except (OSError, json.JSONDecodeError) as exc:
        logger.warning("读取 skills feed 本地缓存失败: %s", exc)
        return None


def _save_disk_cache(data: dict[str, Any]) -> None:
    CACHE_DIR.mkdir(parents=True, exist_ok=True)
    CACHE_FILE.write_text(json.dumps(data, ensure_ascii=False), encoding="utf-8")


def load_feed(force: bool = False) -> dict[str, Any]:
    now = time.time()
    if not force and _cache["data"] and now - _cache["fetched_at"] < CACHE_TTL_SECONDS:
        return _cache["data"]

    errors: list[str] = []
    for url in FEED_URLS:
        for attempt in range(3):
            try:
                data = _fetch_json(url)
                _cache["data"] = data
                _cache["fetched_at"] = now
                _save_disk_cache(data)
                logger.info("skills 数据已更新: %s", url)
                return data
            except Exception as exc:
                msg = f"{url} (#{attempt + 1}): {exc}"
                errors.append(msg)
                logger.debug("拉取失败 %s", msg)
                time.sleep(0.5 * (attempt + 1))

    stale = _load_disk_cache()
    if stale:
        logger.warning("网络不可用，回退到本地 skills feed 缓存")
        _cache["data"] = stale
        _cache["fetched_at"] = now
        return stale

    raise RuntimeError(f"无法获取 skills 数据。最近错误: {errors[-1]}")


def warm_feed_cache() -> None:
    """启动时预加载，避免首条消息才触发网络请求。"""
    load_feed(force=True)


def format_installs(n: int | float) -> str:
    if n >= 1_000_000:
        return f"{n / 1_000_000:.1f}M"
    if n >= 1_000:
        return f"{n / 1_000:.1f}K"
    return str(int(n))


def board_items(feed: dict[str, Any], board: Board) -> list[dict[str, Any]]:
    return feed.get(BOARD_FEED_KEYS[board], [])