布林通道 (Bollinger Bands) → 捕捉波動性、超買超賣區域。
成交量移動平均 (Volume MA) → 反映成交量趨勢，避免假突破。
價格變動率 (ROC) → 衡量動能 (momentum)，看價格變化幅度。

        # --- 新增特徵 ---
    # 1. 布林通道 (Bollinger Bands)
    df['BB_Mid'] = df['MA20']
    df['BB_Upper'] = df['MA20'] + 2 * df['close'].rolling(window=20).std()
    df['BB_Lower'] = df['MA20'] - 2 * df['close'].rolling(window=20).std()

    # 2. 成交量移動平均
    df['Vol_MA20'] = df['volume'].rolling(window=20).mean()

    # 3. 價格變動率 (ROC)
    df['ROC'] = df['close'].pct_change(periods=10) * 100

    return df

# -------------------------
# Step 3: 準備 ML 數據集
# -------------------------
def prepare_ml_data(df):
    df['Future_Close'] = df['close'].shift(-1)
    df['Target'] = (df['Future_Close'] > df['close']).astype(int)

    features = [
        'MA20', 'MA50', 'RSI', 'MACD', 'Signal',
        'BB_Mid', 'BB_Upper', 'BB_Lower',
        'Vol_MA20', 'ROC'
    ]
    df = df.dropna()  # 移除 NaN

    X = df[features]
    y = df['Target']

    return X, y