from __future__ import annotations

from urllib.parse import quote


def normalize_base_path(raw_value: str) -> str:
    # 空串表示应用直接挂在根路径。
    cleaned = str(raw_value or "").strip().strip("/")
    if not cleaned:
        return ""
    return f"/{cleaned}"


def join_base_path(base_path: str, local_path: str) -> str:
    # 统一保证 local path 至少以 / 开头，避免拼接出脏 URL。
    normalized_local = local_path if str(local_path or "").startswith("/") else f"/{local_path}"
    return f"{normalize_base_path(base_path)}{normalized_local}" or "/"


def strip_base_path(base_path: str, request_path: str) -> str | None:
    normalized_base = normalize_base_path(base_path)
    normalized_request = request_path if str(request_path or "").startswith("/") else f"/{request_path}"

    # 根路径应用直接返回原路径。
    if not normalized_base:
        return normalized_request

    # /yumi 本身视作根页面。
    if normalized_request == normalized_base:
        return "/"

    # 其余请求必须严格落在当前 base path 下。
    required_prefix = f"{normalized_base}/"
    if not normalized_request.startswith(required_prefix):
        return None

    return normalized_request[len(normalized_base) :] or "/"


def login_redirect_target(request_target: str) -> str:
    # 未登录回跳保留原始路径和 query。
    return f"/login?next={quote(str(request_target or '/'), safe='')}"