"""独立读取 ETF 参数，不修改现有账户策略的默认行为。"""

from dataclasses import dataclass, fields
from pathlib import Path
import math
import re
import yaml


@dataclass(frozen=True)
class ETFConfig:
    codes: tuple[str, ...] = ()
    buy_hands: int = 1
    max_hands: int = 10
    atr_period: int = 14
    atr_multiplier: float = 1.0
    boll_period: int = 20
    boll_std: float = 2.0
    min_grid_pct: float = 0.5
    rebound_pct: float = 0.61
    watch_seconds: int = 600
    min_profit_pct: float = 0.5
    commission_rate: float = 0.0003
    min_commission: float = 5.0
    max_tick_age_seconds: int = 90

    def __post_init__(self):
        # 限定沪深场内 ETF 代码形态；具体跟踪 A 股的标的由配置白名单决定。
        if not isinstance(self.codes, (list, tuple)) or not self.codes:
            raise ValueError('etf.yaml 的 codes 必须是非空 ETF 代码列表')
        if any(not isinstance(c, str) or not re.fullmatch(r'(?:5[0-9]{5}\.SH|1[58][0-9]{4}\.SZ)', c)
               for c in self.codes) or len(set(self.codes)) != len(self.codes):
            raise ValueError('ETF 代码必须唯一，使用完整沪深场内代码，如 510300.SH、159915.SZ')
        object.__setattr__(self, 'codes', tuple(self.codes))
        for name in ('buy_hands', 'max_hands', 'atr_period', 'boll_period', 'watch_seconds', 'max_tick_age_seconds'):
            if type(getattr(self, name)) is not int or getattr(self, name) <= 0:
                raise ValueError(f'{name} 必须为正整数')
        if not self.buy_hands <= self.max_hands <= 10:
            raise ValueError('必须满足 buy_hands <= max_hands <= 10，每手 100 份')
        if not 2 <= self.atr_period <= 60 or not 2 <= self.boll_period <= 60:
            raise ValueError('ATR、BOLL 周期必须在 2 到 60 日之间')
        for name in ('atr_multiplier', 'boll_std', 'min_grid_pct', 'rebound_pct', 'min_profit_pct',
                     'commission_rate', 'min_commission'):
            value = getattr(self, name)
            if isinstance(value, bool) or not isinstance(value, (int, float)) or not math.isfinite(value) or value < 0:
                raise ValueError(f'{name} 必须是有限非负数')
            if name not in ('commission_rate', 'min_commission') and value == 0:
                raise ValueError(f'{name} 必须大于零')


def load(path: str | Path | None = None) -> ETFConfig:
    path = Path(path) if path else Path(__file__).resolve().parents[2] / 'etc' / '_etf.yaml'
    try:
        raw = yaml.safe_load(path.read_text(encoding='utf-8'))
    except (OSError, yaml.YAMLError) as exc:
        raise ValueError(f'ETF 配置读取失败：{path}') from exc
    if not isinstance(raw, dict) or set(raw) - {f.name for f in fields(ETFConfig)}:
        raise ValueError('ETF 配置必须为对象，且不能包含未知参数')
    return ETFConfig(**raw)