基于天文算法的中国传统干支历法（八字）精确计算工具，支持自定义观测地点。

chinese_ganzhi_calendar.py

import math
import ephem
from datetime import datetime, timedelta, UTC
from typing import Union, Tuple
from functools import lru_cache

class ChineseCalendar:
    """中国传统干支历法计算工具"""
    
    # 天干和地支表
    GAN = ["甲", "乙", "丙", "丁", "戊", "己", "庚", "辛", "壬", "癸"]
    ZHI = ["子", "丑", "寅", "卯", "辰", "巳", "午", "未", "申", "酉", "戌", "亥"]
    
    def __init__(self, latitude: Union[str, float] = 34.545811, longitude: Union[str, float] = 108.925825):
        """
        初始化干支历法计算工具
        
        参数:
            latitude: 观测者纬度，默认为西安纬度
            longitude: 观测者经度，默认为西安经度
        """
        self.latitude = latitude
        self.longitude = longitude
    
    @staticmethod
    @lru_cache(maxsize=1)
    def get_timezone_offset() -> float:
        """获取当前环境的时区偏移值，舍入到最接近的0.5小时"""
        try:
            # 获取当前本地时间和UTC时间
            current_time = datetime.now().replace(tzinfo=None)
            utc_time = datetime.now(UTC).replace(tzinfo=None)
            
            # 计算时区差值
            hours_diff = (current_time - utc_time).total_seconds() / 3600.0
            
            # 舍入到最接近的0.5小时
            if hours_diff >= 0:
                return math.floor(hours_diff / 0.5 + 0.5) * 0.5
            else:
                return math.ceil(hours_diff / 0.5 - 0.5) * 0.5
        except Exception as e:
            print(f"时区计算错误: {e}")
            return 8.0  # 默认东八区
    
    def create_observer(self) -> ephem.Observer:
        """创建并配置观测者对象"""
        observer = ephem.Observer()
        observer.lat = ephem.degrees(str(self.latitude))
        observer.lon = ephem.degrees(str(self.longitude))
        return observer
    
    def get_true_solar_time(self, local_time: datetime) -> datetime:
        """
        计算真太阳时
        
        参数:
            local_time: 本地时间
            
        返回:
            datetime: 调整后的真太阳时
        """
        try:
            # 获取时区偏移
            tz_offset = self.get_timezone_offset()
            
            # 创建观测者对象
            observer = self.create_observer()
            
            # 将本地时间转换为UTC时间
            utc_time = local_time - timedelta(hours=tz_offset)
            observer.date = ephem.Date(utc_time)
            
            # 计算太阳位置和日午时间
            sun = ephem.Sun(observer)
            next_noon = observer.next_transit(sun).datetime() + timedelta(hours=tz_offset)
            
            # 计算钟表正午时间
            clock_noon = next_noon.replace(hour=12, minute=0, second=0, microsecond=0)
            
            # 计算时间差值
            time_diff = (clock_noon - next_noon).total_seconds() / 3600.0
            
            # 调整本地时间获得真太阳时
            return local_time + timedelta(hours=time_diff)
        except Exception as e:
            print(f"真太阳时计算错误: {e}")
            return local_time
    
    def get_solar_longitude(self, local_time: datetime) -> float:
        """计算太阳视黄经（度）"""
        try:
            # 创建观测者对象
            observer = self.create_observer()
            
            # 计算时区偏移
            tz_offset = self.get_timezone_offset()
            
            # 将本地时间转换为UTC时间
            utc_time = local_time - timedelta(hours=tz_offset)
            observer.date = ephem.Date(utc_time)
            
            # 计算太阳位置
            sun = ephem.Sun(observer)
            
            # 获取太阳的视黄经
            equ = ephem.Equatorial(sun.ra, sun.dec, epoch=observer.date)
            ecl = ephem.Ecliptic(equ)
            return (float(ecl.lon) * 180.0 / ephem.pi) % 360.0
        except Exception as e:
            print(f"太阳视黄经计算错误: {e}")
            return 0.0
    
    def get_year_gan_zhi(self, local_time: datetime) -> str:
        """计算年柱"""
        try:
            # 2000年立春时间
            start_date = datetime(2000, 2, 4, 20, 40, 24)
            
            # 计算真太阳时
            true_solar_time = self.get_true_solar_time(local_time)
            
            # 计算与2000年立春的天数差
            diff_days = (true_solar_time - start_date).days
            
            # 回归年长度计算
            day_per_year = 365.24218968 - 0.0000000616 * (diff_days / 365.24218968 / 2)
            years = math.floor(diff_days / day_per_year)
            
            # 2000年是庚辰年
            gan_index = (years + 6) % 10  # 加6位
            zhi_index = (years + 4) % 12  # 加4位
            
            return self.GAN[gan_index] + self.ZHI[zhi_index]
        except Exception as e:
            print(f"年干支计算错误: {e}")
            return "未知"
    
    def get_month_gan_zhi(self, local_time: datetime) -> str:
        """计算月柱"""
        try:
            # 获取太阳视黄经
            solar_longitude = self.get_solar_longitude(local_time)
            
            # 己卯月始于2000年3月5日14:42:40（惊蛰）
            start_date = datetime(2000, 3, 5, 14, 42, 40)
            diff_days = (local_time - start_date).days
            
            # 计算月的平均长度
            day_per_month = (365.24218968 - 0.0000000616 * (diff_days / 365.24218968 / 2)) / 12
            
            # 从己卯月开始的第几个月
            moon_num = int(diff_days / day_per_month)
            
            # 根据太阳黄经计算月支
            solar_month = (int(((solar_longitude - 15) % 360) / 30.0) + 4) % 12
            
            # 近似月支
            approx_month = (moon_num + 3) % 12
            
            # 修正值
            correction = (solar_month - approx_month + 12) % 12
            if correction >= 6:
                correction -= 12
                
            moon_num += correction
            
            # 计算干支索引
            gan_index = (moon_num + 5) % 10  # 加5位
            zhi_index = (moon_num + 3) % 12  # 加3位
            
            return self.GAN[gan_index] + self.ZHI[zhi_index]
        except Exception as e:
            print(f"月干支计算错误: {e}")
            return "未知"
    
    def get_day_gan_zhi(self, local_time: datetime) -> str:
        """计算日柱"""
        try:
            # 1900年1月1日是甲戌日
            start_date = datetime(1900, 1, 1, 0, 0, 0)
            
            # 计算真太阳时
            true_solar_time = self.get_true_solar_time(local_time)
            
            # 计算天数差
            diff_days = (true_solar_time - start_date).days
            
            # 计算干支索引
            gan_index = diff_days % 10
            zhi_index = (diff_days + 10) % 12  # 加10位
            
            return self.GAN[gan_index] + self.ZHI[zhi_index]
        except Exception as e:
            print(f"日干支计算错误: {e}")
            return "未知"
    
    def get_hour_gan_zhi(self, local_time: datetime) -> str:
        """计算时柱"""
        try:
            # 计算真太阳时
            true_solar_time = self.get_true_solar_time(local_time)
            
            # 甲子月甲申日甲子时真太阳时起始点
            start_time = datetime(1983, 12, 21, 23, 42, 15)
            
            # 计算已经过去的时辰数
            hours_diff = (true_solar_time - start_time).total_seconds() / 3600.0
            time_periods = round(hours_diff / 2.0)
            
            # 子时的起点是真太阳时23:00:00，进行修正
            hour_correction = ((((true_solar_time.hour + 1) // 2 - time_periods) % 12) + 12) % 12
            if hour_correction >= 6:
                hour_correction -= 12
                
            time_periods += hour_correction
            
            # 计算干支索引
            gan_index = time_periods % 10
            zhi_index = time_periods % 12
            
            return self.GAN[gan_index] + self.ZHI[zhi_index]
        except Exception as e:
            print(f"时干支计算错误: {e}")
            return "未知"
    
    def get_bazi(self, local_time: datetime) -> Tuple[str, str, str, str]:
        """
        计算八字（四柱干支）
        
        参数:
            local_time: 本地时间
            
        返回:
            Tuple[str, str, str, str]: (年柱, 月柱, 日柱, 时柱)
        """
        year_gz = self.get_year_gan_zhi(local_time)
        month_gz = self.get_month_gan_zhi(local_time)
        day_gz = self.get_day_gan_zhi(local_time)
        hour_gz = self.get_hour_gan_zhi(local_time)
        
        return (year_gz, month_gz, day_gz, hour_gz)


def parse_datetime(date_str: str) -> datetime:
    """解析日期时间字符串"""
    try:
        return datetime.strptime(date_str, '%Y-%m-%d %H:%M:%S')
    except ValueError as e:
        print(f"日期解析错误: {e}")
        print("使用当前时间代替")
        return datetime.now()


# 使用示例
if __name__ == "__main__":
    # 解析日期字符串
    date_str = '2025-5-2 23:48:30'
    date = parse_datetime(date_str)
    
    # 创建中国历法计算对象（指定观测位置）
    calendar = ChineseCalendar(latitude='39.9', longitude='110.8333')
    
    # 计算八字
    year_gz, month_gz, day_gz, hour_gz = calendar.get_bazi(date)
    
    # 打印结果
    print(f"{date_str} 的八字：")
    print(f"年柱：{year_gz}")
    print(f"月柱：{month_gz}")
    print(f"日柱：{day_gz}")
    print(f"时柱：{hour_gz}")