from fastapi import FastAPI, Depends, HTTPException, status
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm

app = FastAPI()

# OAuth2PasswordBearer 类用于处理密码和 Bearer Token
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")

# 模拟的用户数据
fake_users_db = {
    "fakeuser": {
        "username": "fakeuser",
        "hashed_password": "fakehashedpassword",
        "email": "fakeuser@example.com",
    }
}

# 模拟函数，用于验证用户名和密码
def verify_user(username: str, password: str):
    user = fake_users_db.get(username)
    if user and user["hashed_password"] == password:
        return user

# 模拟函数，用于获取当前用户信息
def get_current_user(token: str = Depends(oauth2_scheme)):
    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Invalid credentials",
        headers={"WWW-Authenticate": "Bearer"},
    )
    user_info = verify_user(token, token)
    if user_info is None:
        raise credentials_exception
    return user_info

# 登录路径操作，使用 OAuth2PasswordRequestForm 从表单获取用户名和密码
@app.post("/token")
async def login(form_data: OAuth2PasswordRequestForm = Depends()):
    user_info = verify_user(form_data.username, form_data.password)
    if user_info is None:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Invalid credentials",
            headers={"WWW-Authenticate": "Bearer"},
        )

    return {"access_token": user_info["username"], "token_type": "bearer"}

# 受保护的路径操作，使用 get_current_user 依赖项获取当前用户信息
@app.get("/users/me", response_model=dict)
async def read_users_me(current_user: dict = Depends(get_current_user)):
    return current_user