from dataclasses import dataclass, field
from datetime import date
from typing import Optional
import pandas as pd


@dataclass
class DailyBar:
    """Single daily bar for one stock."""
    symbol: str
    date: date
    open: float
    high: float
    low: float
    close: float
    volume: float
    amount: float  # turnover in yuan

    @classmethod
    def from_dataframe(cls, df: pd.DataFrame, symbol_col: str = "symbol") -> list["DailyBar"]:
        """Convert akshare/baostock DataFrame to list of DailyBar."""
        bars = []
        for _, row in df.iterrows():
            bars.append(cls(
                symbol=row.get(symbol_col, ""),
                date=pd.Timestamp(row["date"]).date(),
                open=float(row["open"]),
                high=float(row["high"]),
                low=float(row["low"]),
                close=float(row["close"]),
                volume=float(row["volume"]),
                amount=float(row.get("amount", 0)),
            ))
        return bars

    def to_series(self) -> dict:
        return {
            "date": self.date,
            "open": self.open,
            "high": self.high,
            "low": self.low,
            "close": self.close,
            "volume": self.volume,
        }