# -*- coding: utf-8 -*-

"""
策略基类
定义所有交易策略需要遵循的接口和通用功能
"""

from abc import ABC, abstractmethod
import pandas as pd
import logging


class BaseStrategy(ABC):
    """
    交易策略基类
    所有具体策略需要继承此类并实现抽象方法
    """
    
    def __init__(self):
        """
        初始化策略
        """
        self.name = self.__class__.__name__
        self.logger = logging.getLogger(f'strategy.{self.name}')
        self.signals = None  # 存储生成的交易信号
        self.positions = []  # 记录持仓历史
        self.current_position = 0  # 当前持仓数量
        self.params = {}
        
        self.logger.info(f'策略 {self.name} 初始化完成')
    
    @abstractmethod
    def initialize(self, data):
        """
        初始化策略，处理数据，计算指标等
        
        Args:
            data: 股票数据DataFrame
        """
        pass
    
    @abstractmethod
    def generate_signals(self, data):
        """
        生成交易信号
        
        Args:
            data: 股票数据DataFrame
            
        Returns:
            pandas.DataFrame: 添加了信号列的DataFrame
        """
        pass
    
    @abstractmethod
    def on_signal(self, date, signal, price):
        """
        处理交易信号
        
        Args:
            date: 日期
            signal: 信号类型 (1=买入, 0=持有, -1=卖出)
            price: 价格
            
        Returns:
            dict: 交易指令 {action: 'buy'|'sell'|'hold', quantity: int}
        """
        pass
    
    def set_params(self, **kwargs):
        """
        设置策略参数
        
        Args:
            **kwargs: 策略参数
        """
        for key, value in kwargs.items():
            self.params[key] = value
        self.logger.info(f'策略参数已更新: {self.params}')
    
    def calculate_indicators(self, data):
        """
        计算技术指标
        
        Args:
            data: 原始数据
            
        Returns:
            pandas.DataFrame: 添加了指标列的数据
        """
        # 默认实现，子类可以覆盖此方法
        return data.copy()
    
    def _calculate_moving_average(self, data, period):
        """
        计算移动平均线
        
        Args:
            data: 数据
            period: 周期
            
        Returns:
            pandas.Series: 移动平均线
        """
        return data['close'].rolling(window=period).mean()
    
    def _calculate_volume_ma(self, data, period):
        """
        计算成交量移动平均线
        
        Args:
            data: 数据
            period: 周期
            
        Returns:
            pandas.Series: 成交量移动平均线
        """
        return data['volume'].rolling(window=period).mean()
    
    def _calculate_rsi(self, data, period=14):
        """
        计算RSI指标
        
        Args:
            data: 数据
            period: 周期
            
        Returns:
            pandas.Series: RSI值
        """
        delta = data['close'].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_macd(self, data, fast_period=12, slow_period=26, signal_period=9):
        """
        计算MACD指标
        
        Args:
            data: 数据
            fast_period: 快线周期
            slow_period: 慢线周期
            signal_period: 信号线周期
            
        Returns:
            tuple: (MACD线, 信号线, 柱状图)
        """
        exp1 = data['close'].ewm(span=fast_period, adjust=False).mean()
        exp2 = data['close'].ewm(span=slow_period, adjust=False).mean()
        macd = exp1 - exp2
        signal = macd.ewm(span=signal_period, adjust=False).mean()
        histogram = macd - signal
        return macd, signal, histogram
    
    def record_position(self, date, action, quantity, price):
        """
        记录交易和持仓信息
        
        Args:
            date: 交易日期
            action: 交易动作 ('buy'|'sell'|'hold')
            quantity: 交易数量
            price: 交易价格
        """
        if action == 'buy':
            self.current_position += quantity
        elif action == 'sell':
            self.current_position -= quantity
        
        # 确保持仓不会变成负数
        if self.current_position < 0:
            self.current_position = 0
        
        trade_record = {
            'date': date,
            'action': action,
            'quantity': quantity,
            'price': price,
            'position': self.current_position
        }
        
        self.positions.append(trade_record)
        self.logger.debug(f'记录交易: {trade_record}')
    
    def get_trading_summary(self):
        """
        获取交易汇总信息
        
        Returns:
            dict: 交易汇总
        """
        if not self.positions:
            return {
                'total_trades': 0,
                'buy_trades': 0,
                'sell_trades': 0,
                'current_position': 0
            }
        
        buy_trades = sum(1 for p in self.positions if p['action'] == 'buy')
        sell_trades = sum(1 for p in self.positions if p['action'] == 'sell')
        
        return {
            'total_trades': buy_trades + sell_trades,
            'buy_trades': buy_trades,
            'sell_trades': sell_trades,
            'current_position': self.current_position,
            'first_trade_date': self.positions[0]['date'],
            'last_trade_date': self.positions[-1]['date']
        }
    
    def reset(self):
        """
        重置策略状态
        """
        self.signals = None
        self.positions = []
        self.current_position = 0
        self.logger.info(f'策略 {self.name} 已重置')