# knowledge.py
import json
import os
import re

BASE_DIR = os.path.dirname(__file__)
COURSE_DB_PATH = os.path.join(BASE_DIR, "courses.json")

with open(COURSE_DB_PATH, "r", encoding="utf-8") as f:
    COURSE_DB = json.load(f)

def lookup_course(course_name: str) -> str:
    course_name = course_name.strip()
    if course_name in COURSE_DB:
        # 将知识点按“第n章”或“；”分割，并每章换行
        content = COURSE_DB[course_name]
        # 优先按“第n章”分割
        chapters = re.split(r'(第[0-9一二三四五六七八九十]+章：[^；；。]*)[；。]?', content)
        # re.split会保留分组内容，需合并
        result = []
        i = 1
        while i < len(chapters):
            if chapters[i]:
                result.append(chapters[i].strip())
            i += 2
        # 如果没有“第n章”，则按“；”分割
        if not result:
            result = [x.strip() for x in re.split(r'[；;]', content) if x.strip()]
        return '\n'.join(result)
    else:
        return f"未在本地知识库中找到“{course_name}”，你可以输入其他课程名或使用 LLM 问答模式。"