"""
K线 WebSocket 流：订阅 <symbol>@kline_<interval>，维护K线缓存。
供 get_klines 优先使用，替代 REST 拉取，减少超时、实时更新技术指标。
文档：推送间隔 250ms，仅推送最新一根K线的更新；x=false 表示K线未完结，x=true 表示已完结。
"""
import asyncio
import json
import logging
import time
from typing import Dict, List, Optional, Any, Tuple

logger = logging.getLogger(__name__)

# K线缓存：{ (symbol, interval): [kline1, kline2, ...] }，最多保留 limit 根
_kline_cache: Dict[Tuple[str, str], List[List]] = {}
_kline_cache_updated_at: Dict[Tuple[str, str], float] = {}
_kline_cache_limit: Dict[Tuple[str, str], int] = {}  # 每个 (symbol, interval) 的 limit


def get_klines_from_cache(symbol: str, interval: str, limit: int = 50) -> Optional[List[List]]:
    """从缓存返回K线数据（与 REST get_klines 格式兼容）。未订阅或数据不足时返回 None。"""
    key = (symbol.upper(), interval.lower())
    cached = _kline_cache.get(key)
    if not cached or len(cached) < limit:
        return None
    # 返回最后 limit 根
    return cached[-limit:]


def is_kline_cache_fresh(symbol: str, interval: str, max_age_sec: float = 300.0) -> bool:
    """缓存是否在 max_age_sec 秒内更新过。"""
    key = (symbol.upper(), interval.lower())
    updated = _kline_cache_updated_at.get(key, 0)
    if updated == 0:
        return False
    return (time.monotonic() - updated) <= max_age_sec


class KlineStream:
    """订阅合约 K线流，持续更新 _kline_cache。支持动态订阅/取消订阅。"""

    def __init__(self, testnet: bool = False):
        self.testnet = testnet
        self._ws = None
        self._task: Optional[asyncio.Task] = None
        self._running = False
        self._subscribed: Dict[Tuple[str, str], bool] = {}  # (symbol, interval) -> 是否已订阅
        self._subscription_lock = asyncio.Lock()

    def _ws_base_url(self) -> str:
        if self.testnet:
            return "wss://stream.binancefuture.com"
        return "wss://fstream.binance.com"

    async def start(self) -> bool:
        global _kline_stream_instance
        if self._running:
            return True
        self._running = True
        _kline_stream_instance = self
        self._task = asyncio.create_task(self._run_ws())
        logger.info("KlineStream: 已启动（支持动态订阅）")
        return True

    async def stop(self):
        global _kline_stream_instance
        self._running = False
        _kline_stream_instance = None
        if self._task:
            self._task.cancel()
            try:
                await self._task
            except asyncio.CancelledError:
                pass
            self._task = None
        if self._ws:
            try:
                await self._ws.close()
            except Exception:
                pass
            self._ws = None
        logger.info("KlineStream: 已停止")

    async def subscribe(self, symbol: str, interval: str, limit: int = 50) -> bool:
        """订阅指定 symbol 和 interval 的K线流（若 WS 未连接则等待连接后订阅）。"""
        symbol = symbol.upper()
        interval = interval.lower()
        key = (symbol, interval)
        async with self._subscription_lock:
            if self._subscribed.get(key):
                return True
            if not self._running:
                return False
            # 等待 WS 连接（最多等待 5 秒）
            for _ in range(50):
                if self._ws:
                    break
                await asyncio.sleep(0.1)
            if not self._ws:
                return False
            stream_name = f"{symbol.lower()}@kline_{interval}"
            try:
                await self._ws.send_json({
                    "method": "SUBSCRIBE",
                    "params": [stream_name],
                    "id": int(time.time() * 1000) % 1000000,
                })
                self._subscribed[key] = True
                _kline_cache_limit[key] = limit
                logger.debug(f"KlineStream: 已订阅 {symbol} {interval}")
                return True
            except Exception as e:
                logger.warning(f"KlineStream: 订阅 {symbol} {interval} 失败: {e}")
                return False

    async def _run_ws(self):
        import aiohttp
        # 使用组合流，支持动态订阅
        url = f"{self._ws_base_url()}/stream"
        while self._running:
            try:
                async with aiohttp.ClientSession() as session:
                    async with session.ws_connect(
                        url, heartbeat=50, timeout=aiohttp.ClientTimeout(total=15)
                    ) as ws:
                        self._ws = ws
                        logger.info("KlineStream: WS 已连接（组合流，支持动态订阅）")
                        async for msg in ws:
                            if not self._running:
                                break
                            if msg.type == aiohttp.WSMsgType.TEXT:
                                raw = msg.data
                                # 处理订阅响应（{"result": null, "id": ...}）或K线数据
                                try:
                                    data = json.loads(raw)
                                    if isinstance(data, dict) and "result" in data:
                                        # 订阅响应，忽略
                                        continue
                                except Exception:
                                    pass
                                self._handle_message(raw)
                            elif msg.type in (aiohttp.WSMsgType.ERROR, aiohttp.WSMsgType.CLOSED, aiohttp.WSMsgType.CLOSE):
                                break
            except asyncio.CancelledError:
                break
            except Exception as e:
                err_msg = getattr(e, "message", str(e)) or repr(e)
                err_type = type(e).__name__
                logger.warning(
                    "KlineStream: WS 异常 %s: %s，10s 后重连",
                    err_type, err_msg,
                    exc_info=logger.isEnabledFor(logging.DEBUG),
                )
                await asyncio.sleep(10)
            self._ws = None
            # 重连时清空订阅状态，需要重新订阅
            async with self._subscription_lock:
                self._subscribed.clear()
            if not self._running:
                break

    def _handle_message(self, raw: str):
        global _kline_cache, _kline_cache_updated_at
        try:
            data = json.loads(raw)
        except Exception:
            return
        # 组合流格式：{ "stream": "btcusdt@kline_1h", "data": {...} }
        if isinstance(data, dict) and "stream" in data:
            stream = data.get("stream", "")
            kline_data = data.get("data", {})
        else:
            kline_data = data
            stream = ""

        if not isinstance(kline_data, dict) or kline_data.get("e") != "kline":
            return

        k = kline_data.get("k")
        if not isinstance(k, dict):
            return

        s = (k.get("s") or "").strip().upper()
        i = (k.get("i") or "").strip().lower()
        if not s or not i:
            return

        key = (s, i)
        if key not in self._subscribed:
            return

        # 转换为 REST 格式：[open_time, open, high, low, close, volume, close_time, quote_volume, trades, ...]
        try:
            t = int(k.get("t", 0))
            o = float(k.get("o", 0))
            h = float(k.get("h", 0))
            l = float(k.get("l", 0))
            c = float(k.get("c", 0))
            v = float(k.get("v", 0))
            T = int(k.get("T", 0))
            q = float(k.get("q", 0))
            n = int(k.get("n", 0))
            x = k.get("x", False)  # 是否完结
        except (TypeError, ValueError):
            return

        kline_rest_format = [
            t,      # open_time
            str(o), # open
            str(h), # high
            str(l), # low
            str(c), # close
            str(v), # volume
            T,      # close_time
            str(q), # quote_volume
            n,      # trades
            "0",    # taker_buy_base_volume
            "0",    # taker_buy_quote_volume
            "0",    # ignore
        ]

        # 更新缓存：若 x=true（完结），追加新K线；若 x=false（未完结），更新最后一根
        if key not in _kline_cache:
            _kline_cache[key] = []
        cache_list = _kline_cache[key]

        if x:
            # K线完结：追加新K线
            cache_list.append(kline_rest_format)
            limit = _kline_cache_limit.get(key, 50)
            if len(cache_list) > limit * 2:
                cache_list[:] = cache_list[-limit:]
        else:
            # K线未完结：更新最后一根（或追加第一根）
            if cache_list:
                cache_list[-1] = kline_rest_format
            else:
                cache_list.append(kline_rest_format)

        _kline_cache_updated_at[key] = time.monotonic()
        logger.debug(f"KlineStream: 已更新 {s} {i} (完结={x})，缓存 {len(cache_list)} 根")


# 全局 KlineStream 实例
_kline_stream_instance: Optional["KlineStream"] = None


def get_kline_stream_instance() -> Optional["KlineStream"]:
    """返回当前运行的 KlineStream 实例（未启动时为 None）。"""
    return _kline_stream_instance


def set_kline_stream_instance(instance: Optional["KlineStream"]):
    """设置全局 KlineStream 实例（由 main 调用）。"""
    global _kline_stream_instance
    _kline_stream_instance = instance