# converter.py
import os
import json
from datetime import datetime
from typing import List, Optional

class Converter:
    """
    提供西曆與農曆互轉功能，並能判斷特定年份的閏月。
    """
    LUNAR_JSON_DIR = 'lunar_json'

    def __init__(self):
        """初始化時，建立一個空的快取來存放已查詢過的年份閏月資訊。"""
        self._leap_month_cache = {}

    @classmethod
    def load_solar_to_lunar(cls, year: int) -> dict:
        """這是一個類別方法，用來載入指定年份的資料檔。"""
        path = os.path.join(cls.LUNAR_JSON_DIR, f"{year}.json")
        if not os.path.exists(path):
            raise FileNotFoundError(f"找不到農曆資料檔: {path}")
        with open(path, encoding='utf-8') as f:
            return json.load(f)

    def solar_to_lunar(self, solar_date_str: str) -> dict:
        try:
            dt = datetime.strptime(solar_date_str, '%Y-%m-%d').date()
        except ValueError:
            raise ValueError("西曆日期格式應為 YYYY-MM-DD")
        # 【修正點】從 self. 呼叫改為 Converter. 呼叫
        data = Converter.load_solar_to_lunar(dt.year)
        if solar_date_str not in data:
            raise KeyError(f"沒有找到對應 {solar_date_str} 的農曆資料")
        return data[solar_date_str]

    def lunar_to_solar(self, lunar_year: int, lunar_month: int, lunar_day: int, leap: bool=False) -> str:
        years_to_check = {lunar_year, lunar_year + 1}
        for year in sorted(list(years_to_check)):
            try:
                # 【修正點】從 self. 呼叫改為 Converter. 呼叫
                data = Converter.load_solar_to_lunar(year)
                for solar_date, info in data.items():
                    lstr = info.get('農曆', '')
                    is_leap = lstr.startswith('閏')
                    core = lstr[1:] if is_leap else lstr
                    if not all(c in core for c in ['月', '日']): continue
                    m_str, d_str = core.replace('月','-').replace('日','').split('-')
                    if int(m_str) == lunar_month and int(d_str) == lunar_day and is_leap == leap:
                        return info.get("西曆")
            except FileNotFoundError:
                continue
        raise KeyError(f"找不到對應農曆 {lunar_year}{'閏' if leap else ''}{lunar_month}月{lunar_day}日 的西曆")

    def lunar_to_solar_all(self, lunar_year: int, lunar_month: int, lunar_day: int) -> List[str]:
        results = []
        try:
            solar_date = self.lunar_to_solar(lunar_year, lunar_month, lunar_day, leap=False)
            results.append(solar_date)
        except KeyError:
            pass
        try:
            solar_date = self.lunar_to_solar(lunar_year, lunar_month, lunar_day, leap=True)
            results.append(solar_date)
        except KeyError:
            pass
        return results

    def get_leap_month(self, year: int) -> Optional[int]:
        if year in self._leap_month_cache:
            return self._leap_month_cache[year]
        try:
            # 【修正點】從 self. 呼叫改為 Converter. 呼叫
            data = Converter.load_solar_to_lunar(year)
            for info in data.values():
                lstr = info.get('農曆', '')
                if lstr.startswith('閏'):
                    core = lstr[1:]
                    if '月' in core:
                        month_str = core.split('月')[0]
                        leap_month = int(month_str)
                        self._leap_month_cache[year] = leap_month
                        return leap_month
            self._leap_month_cache[year] = None
            return None
        except FileNotFoundError:
            self._leap_month_cache[year] = None
            return None
            
# ... (main 函式不變) ...
def main():
    """展示 Converter 的新功能：查詢閏月"""
    print("=== Converter 閏月判斷功能展示 ===")
    try:
        converter = Converter()
        years_to_test = [1976, 1977, 2023, 2024, 2025]
        for year in years_to_test:
            leap_month = converter.get_leap_month(year)
            if leap_month:
                print(f"西曆 {year} 年，有閏月，是閏 {leap_month} 月。")
            else:
                print(f"西曆 {year} 年，沒有閏月。")
    except Exception as e:
        print(f"\n發生錯誤: {e}")

if __name__ == '__main__':
    main()