"""模拟盘总账：资金 T+0 / 合并持仓 / 净值盯市（spec §7 双层记账总账层）。

- cash 资金 T+0：卖出回笼资金当日即可再买（A 股硬规则）
- 股票 T+1：买入持仓由 PositionLedger.frozen 管，次日 unfreeze_all 解冻
- transfer_fee：matcher 已出双向总额（review H3），Account 直接用，不再 ×2
- 资金检查 cash_enough 在买单 apply 前由 PaperEngine 调用
"""
from .models import OrderSide, PaperTrade
from .position_ledger import PositionLedger


class Account:
    def __init__(self, initial_capital: float) -> None:
        self.cash: float = float(initial_capital)
        self.positions: dict[str, PositionLedger] = {}
        self.market_value: float = 0.0

    def _position(self, symbol: str) -> PositionLedger:
        if symbol not in self.positions:
            self.positions[symbol] = PositionLedger(symbol)
        return self.positions[symbol]

    def cash_enough(self, trade: PaperTrade) -> bool:
        """买单检查现金是否足够（卖出不检查，持仓检查在 PositionLedger）。"""
        if trade.side != OrderSide.BUY:
            return True
        cost = trade.price * trade.volume + trade.commission + trade.transfer_fee
        return self.cash >= cost

    def apply_trade(self, trade: PaperTrade) -> None:
        pos = self._position(trade.symbol)
        if trade.side == OrderSide.BUY:
            cost = trade.price * trade.volume + trade.commission + trade.transfer_fee
            self.cash -= cost
            pos.apply_buy(trade.price, trade.volume)
        else:
            proceeds = (
                trade.price * trade.volume
                - trade.commission - trade.stamp_duty - trade.transfer_fee
            )
            self.cash += proceeds   # 资金 T+0：卖出现金立即可用
            pos.apply_sell(trade.price, trade.volume)

    def unfreeze_all(self) -> None:
        """每日开盘前：T+1 解冻所有持仓。"""
        for p in self.positions.values():
            p.unfreeze()

    def apply_cash_dividend(self, symbol: str, per_share: float) -> None:
        """现金分红到账：cash += per_share × 持仓量（spec §295）。

        按 A 股惯例按除权日前一交易日持仓量派发；无持仓/非正值 no-op。
        """
        if per_share <= 0:
            return
        pos = self.positions.get(symbol)
        if pos is None or pos.volume <= 0:
            return
        self.cash += per_share * pos.volume

    def mark_to_market(self, bars_raw: dict[str, float],
                       prev_close: dict[str, float] | None = None) -> None:
        """按 raw 收盘价重估合并持仓市值（spec §295 停牌盯市兜底）。

        bar 缺失（停牌）→ 用前日 close 兜底，再退到 avg_price。
        """
        prev_close = prev_close or {}
        self.market_value = sum(
            p.volume * bars_raw.get(sym, prev_close.get(sym, p.avg_price))
            for sym, p in self.positions.items()
        )

    @property
    def equity(self) -> float:
        return self.cash + self.market_value