"""
技术指标计算模块
提供常用技术指标的计算功能
"""
import pandas as pd
import numpy as np
from typing import Tuple


def calculate_ma(data: pd.Series, period: int = 5) -> pd.Series:
    """
    计算移动平均线（MA）

    Args:
        data: 价格数据
        period: 周期

    Returns:
        MA值
    """
    return data.rolling(window=period).mean()


def calculate_ema(data: pd.Series, period: int = 12) -> pd.Series:
    """
    计算指数移动平均线（EMA）

    Args:
        data: 价格数据
        period: 周期

    Returns:
        EMA值
    """
    return data.ewm(span=period, adjust=False).mean()


def calculate_macd(
    data: pd.Series,
    fast_period: int = 12,
    slow_period: int = 26,
    signal_period: int = 9
) -> Tuple[pd.Series, pd.Series, pd.Series]:
    """
    计算MACD指标

    Args:
        data: 价格数据
        fast_period: 快线周期
        slow_period: 慢线周期
        signal_period: 信号线周期

    Returns:
        (DIF, DEA, MACD柱)
    """
    ema_fast = calculate_ema(data, fast_period)
    ema_slow = calculate_ema(data, slow_period)

    dif = ema_fast - ema_slow
    dea = dif.ewm(span=signal_period, adjust=False).mean()
    macd = (dif - dea) * 2

    return dif, dea, macd


def calculate_rsi(data: pd.Series, period: int = 14) -> pd.Series:
    """
    计算相对强弱指标（RSI）

    Args:
        data: 价格数据
        period: 周期

    Returns:
        RSI值
    """
    delta = data.diff()

    gain = (delta.where(delta > 0, 0)).rolling(window=period).mean()
    loss = (-delta.where(delta < 0, 0)).rolling(window=period).mean()

    rs = gain / loss
    rsi = 100 - (100 / (1 + rs))

    return rsi


def calculate_kdj(
    high: pd.Series,
    low: pd.Series,
    close: pd.Series,
    period: int = 9,
    m1: int = 3,
    m2: int = 3
) -> Tuple[pd.Series, pd.Series, pd.Series]:
    """
    计算KDJ指标

    Args:
        high: 最高价
        low: 最低价
        close: 收盘价
        period: 周期
        m1: K值平滑参数
        m2: D值平滑参数

    Returns:
        (K, D, J)
    """
    low_min = low.rolling(window=period).min()
    high_max = high.rolling(window=period).max()

    rsv = (close - low_min) / (high_max - low_min) * 100

    k = rsv.ewm(com=m1 - 1, adjust=False).mean()
    d = k.ewm(com=m2 - 1, adjust=False).mean()
    j = 3 * k - 2 * d

    return k, d, j


def calculate_boll(
    data: pd.Series,
    period: int = 20,
    std_dev: float = 2.0
) -> Tuple[pd.Series, pd.Series, pd.Series]:
    """
    计算布林带（BOLL）

    Args:
        data: 价格数据
        period: 周期
        std_dev: 标准差倍数

    Returns:
        (上轨, 中轨, 下轨)
    """
    middle = data.rolling(window=period).mean()
    std = data.rolling(window=period).std()

    upper = middle + (std * std_dev)
    lower = middle - (std * std_dev)

    return upper, middle, lower


def calculate_adx(
    high: pd.Series,
    low: pd.Series,
    close: pd.Series,
    period: int = 14
) -> Tuple[pd.Series, pd.Series, pd.Series]:
    """
    计算 ADX (Average Directional Index) 趋势强度指标

    ADX 衡量趋势强度（非方向）：
    - ADX < 20: 震荡 / 无趋势
    - ADX 20-25: 过渡期
    - ADX 25-50: 趋势中
    - ADX > 50: 强趋势

    Args:
        high: 最高价
        low: 最低价
        close: 收盘价
        period: 回溯周期 (默认 14)

    Returns:
        (adx, plus_di, minus_di) 元组
    """
    # True Range
    tr1 = high - low
    tr2 = abs(high - close.shift(1))
    tr3 = abs(low - close.shift(1))
    tr = pd.concat([tr1, tr2, tr3], axis=1).max(axis=1)

    # Directional Movement
    up_move = high - high.shift(1)
    down_move = low.shift(1) - low

    plus_dm = pd.Series(
        np.where((up_move > down_move) & (up_move > 0), up_move, 0.0),
        index=high.index
    )
    minus_dm = pd.Series(
        np.where((down_move > up_move) & (down_move > 0), down_move, 0.0),
        index=high.index
    )

    # Wilder's smoothing (EWM alpha=1/period)
    atr = tr.ewm(alpha=1/period, adjust=False).mean()
    plus_di = 100 * (plus_dm.ewm(alpha=1/period, adjust=False).mean() / atr)
    minus_di = 100 * (minus_dm.ewm(alpha=1/period, adjust=False).mean() / atr)

    # DX and ADX
    di_sum = plus_di + minus_di
    di_sum = di_sum.replace(0, np.nan)
    dx = 100 * abs(plus_di - minus_di) / di_sum
    adx = dx.ewm(alpha=1/period, adjust=False).mean()

    return adx, plus_di, minus_di


def calculate_volume_ma(volume: pd.Series, period: int = 5) -> pd.Series:
    """
    计算成交量移动平均

    Args:
        volume: 成交量数据
        period: 周期

    Returns:
        成交量MA
    """
    return volume.rolling(window=period).mean()