from __future__ import annotations

from functools import wraps
from typing import Any, Dict, Iterable, Optional
import inspect

from quart import g, abort, redirect, request, current_app
from shared.urls import login_url


def require_rights(*rights: str, any_of: bool = True):
    """
    Decorator for routes that require certain user rights.
    """

    if not rights:
        raise ValueError("require_rights needs at least one right name")

    required_set = frozenset(rights)

    def decorator(view_func):
        @wraps(view_func)
        async def wrapper(*args: Any, **kwargs: Any):
            # Not logged in → go to login, with ?next=<current path>
            user = g.get("user")
            if not user:
                return redirect(login_url(request.url))

            rights_dict = g.get("rights") or {}

            if any_of:
                allowed = any(rights_dict.get(name) for name in required_set)
            else:
                allowed = all(rights_dict.get(name) for name in required_set)

            if not allowed:
                abort(403)

            result = view_func(*args, **kwargs)
            if inspect.isawaitable(result):
                return await result
            return result

        # ---- expose access requirements on the wrapper ----
        wrapper.__access_requires__ = {
            "rights": required_set,
            "any_of": any_of,
        }

        return wrapper

    return decorator


def require_login(view_func):
    """
    Decorator for routes that require any logged-in user.
    """
    @wraps(view_func)
    async def wrapper(*args: Any, **kwargs: Any):
        user = g.get("user")
        if not user:
            return redirect(login_url(request.url))
        result = view_func(*args, **kwargs)
        if inspect.isawaitable(result):
            return await result
        return result
    return wrapper


def require_admin(view_func=None):
    """
    Shortcut for routes that require the 'admin' right.
    """
    if view_func is None:
        return require_rights("admin")

    return require_rights("admin")(view_func)

def require_post_author(view_func):
    """Allow admin or post owner."""
    @wraps(view_func)
    async def wrapper(*args, **kwargs):
        user = g.get("user")
        if not user:
            return redirect(login_url(request.url))
        is_admin = bool((g.get("rights") or {}).get("admin"))
        if is_admin:
            result = view_func(*args, **kwargs)
            if inspect.isawaitable(result):
                return await result
            return result
        post = getattr(g, "post_data", {}).get("original_post")
        if post and post.user_id == user.id:
            result = view_func(*args, **kwargs)
            if inspect.isawaitable(result):
                return await result
            return result
        abort(403)
    return wrapper


def _get_access_meta(view_func) -> Optional[Dict[str, Any]]:
    """
    Walk the wrapper chain looking for __access_requires__ metadata.
    """
    func = view_func
    seen: set[int] = set()

    while func is not None and id(func) not in seen:
        seen.add(id(func))
        meta = getattr(func, "__access_requires__", None)
        if meta is not None:
            return meta
        func = getattr(func, "__wrapped__", None)

    return None


def has_access(endpoint: str) -> bool:
    """
    Return True if the current user has access to the given endpoint.

    Example:
        has_access("settings.home")
        has_access("settings.clear_cache_view")
    """
    view = current_app.view_functions.get(endpoint)
    if view is None:
        # Unknown endpoint: be conservative
        return False

    meta = _get_access_meta(view)

    # If the route has no rights metadata, treat it as public:
    if meta is None:
        return True

    required: Iterable[str] = meta["rights"]
    any_of: bool = meta["any_of"]

    # Must be in a request context; if no user, they don't have access
    user = g.get("user")
    if not user:
        return False

    rights_dict = g.get("rights") or {}

    if any_of:
        return any(rights_dict.get(name) for name in required)
    else:
        return all(rights_dict.get(name) for name in required)