import json
import urllib.request
import akshare as ak
from datetime import datetime, timedelta
from typing import Optional

# Cache for stock master list
_stock_list_cache: list[dict] = []
_stock_list_ts: Optional[datetime] = None
CACHE_TTL = timedelta(hours=6)


def _load_stock_list() -> list[dict]:
    global _stock_list_cache, _stock_list_ts
    now = datetime.now()
    if _stock_list_cache and _stock_list_ts and (now - _stock_list_ts) < CACHE_TTL:
        return _stock_list_cache
    try:
        df = ak.stock_info_a_code_name()
        _stock_list_cache = df.to_dict(orient="records")
        _stock_list_ts = now
    except Exception:
        if _stock_list_cache:
            return _stock_list_cache
        _stock_list_cache = []
    return _stock_list_cache


def search_stocks(query: str, limit: int = 20) -> list[dict]:
    if not query:
        return []
    stocks = _load_stock_list()
    q = query.upper()
    results = []
    for s in stocks:
        code = str(s.get("code", ""))
        name = str(s.get("name", ""))
        if q in code or q in name:
            results.append({"code": code, "name": name})
            if len(results) >= limit:
                break
    return results


def _sina_symbol(code: str) -> str:
    """Convert 6-digit code to Sina format: sh600519 or sz000001."""
    if code.startswith("6") or code.startswith("9"):
        return f"sh{code}"
    return f"sz{code}"


def _tencent_symbol(code: str) -> str:
    """Convert to Tencent format."""
    if code.startswith("6") or code.startswith("9"):
        return f"sh{code}"
    return f"sz{code}"


def get_kline(code: str, months: int = 12) -> list[dict]:
    """Get daily K-line via Sina Finance."""
    end_date = datetime.now()
    start_date = end_date - timedelta(days=months * 31)
    symbol = _sina_symbol(code)

    # Sina K-line API - scale=240 means daily, datalen estimated
    days_needed = (end_date - start_date).days
    url = (
        f"https://money.finance.sina.com.cn/quotes_service/api/json_v2.php/"
        f"CN_MarketData.getKLineData?symbol={symbol}&scale=240&ma=no&datalen={days_needed}"
    )

    try:
        req = urllib.request.Request(
            url,
            headers={
                "User-Agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7)",
                "Referer": "https://finance.sina.com.cn/",
            },
        )
        with urllib.request.urlopen(req, timeout=15) as resp:
            raw = resp.read().decode("gbk")
            items = json.loads(raw)
    except Exception:
        return []

    results = []
    for item in items:
        results.append({
            "date": item["day"],
            "open": float(item["open"]),
            "close": float(item["close"]),
            "high": float(item["high"]),
            "low": float(item["low"]),
            "volume": float(item.get("volume", 0)),
        })
    return results


def get_realtime_quote(code: str) -> Optional[dict]:
    """Get real-time quote via Tencent Finance."""
    symbol = _tencent_symbol(code)
    url = f"https://qt.gtimg.cn/q={symbol}"

    try:
        req = urllib.request.Request(
            url,
            headers={
                "User-Agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7)",
                "Referer": "https://gu.qq.com/",
            },
        )
        with urllib.request.urlopen(req, timeout=15) as resp:
            raw = resp.read().decode("gbk")
    except Exception:
        return None

    # Tencent format fields:
    # [0]=market [1]=name [2]=code [3]=price [4]=prev_close [5]=open
    # [6]=volume(手) [30]=datetime [31]=change [32]=change_pct [33]=high [34]=low
    try:
        start = raw.index('"') + 1
        end = raw.rindex('"')
        parts = raw[start:end].split("~")
        if len(parts) < 35:
            return None

        price = float(parts[3])
        prev_close = float(parts[4])
        open_p = float(parts[5])
        high = float(parts[33])
        low = float(parts[34])
        change = float(parts[31])
        change_pct = float(parts[32])
        volume_shares = float(parts[6]) * 100  # 手 -> 股

        return {
            "code": code,
            "name": parts[1],
            "price": price,
            "change": change,
            "change_pct": change_pct,
            "high": high,
            "low": low,
            "open": open_p,
            "prev_close": prev_close,
            "volume": volume_shares,
            "amount": 0,
        }
    except (ValueError, IndexError):
        return None