# myapp/services/auth_service.py
import os, uuid, json
from flask import current_app, session

def create_user_json(username: str):
    user_dir = current_app.config["USER_DATA_DIR"]
    os.makedirs(user_dir, exist_ok=True)
    path = os.path.join(user_dir, f"{username}.json")
    if not os.path.exists(path):
        with open(path, "w", encoding="utf-8") as f:
            json.dump({"username": username}, f, ensure_ascii=False)

def register_user(username: str, password: str, *, teacher: bool=False):
    users_list = current_app.extensions["users_list"]
    # 你原逻辑似乎把 has_user 的判断反了：直觉上「不存在才允许新增」
    exists = users_list.has_user(username)
    if exists:
        return False, "用户已存在，请更换用户名"
    users_list.add_user(username, password, teacher=teacher)
    create_user_json(username)
    return True, "注册成功"

def login_user(username: str, password: str, *, require_teacher: bool=False):
    users_list = current_app.extensions["users_list"]
    pswd = users_list.get_user_pswd(username)
    if pswd is None or pswd != password:
        return False, "用户名或密码错误"

    if require_teacher:
        is_teacher = users_list.get_user_is_teacher(username)
        if not is_teacher:
            return False, "用户名不存在或非教师账号"

    # 设置会话 + 关联映射
    user_uuid = "user_" + str(uuid.uuid4())
    session["user_id"] = user_uuid

    username2uuid = current_app.extensions["username2uuid"]
    uuid2username = current_app.extensions["uuid2username"]
    username2uuid[username] = user_uuid
    uuid2username[user_uuid] = username

    return True, "登录成功"

def logout_user():
    session.pop("user_id", None)