"""权限缓存管理器"""

from __future__ import annotations

import time
import uuid
from typing import Any

from sqlalchemy.ext.asyncio import AsyncSession


class PermissionCache:
    """权限缓存管理器"""

    def __init__(self, default_ttl: int = 300):
        self.default_ttl = default_ttl
        self._project_permissions_cache: dict[str, tuple[Any, float]] = {}
        self._member_role_cache: dict[str, tuple[str | None, float]] = {}

    def _is_expired(self, timestamp: float, ttl: int) -> bool:
        return time.time() - timestamp > ttl

    def _make_project_cache_key(self, study_id: uuid.UUID) -> str:
        return f"project_permissions:{study_id}"

    def _make_member_cache_key(self, study_id: uuid.UUID, user_id: uuid.UUID) -> str:
        return f"member_role:{study_id}:{user_id}"

    async def get_member_role(
        self,
        db: AsyncSession,
        study_id: uuid.UUID,
        user_id: uuid.UUID,
        ttl: int | None = None,
    ) -> str | None:
        """获取成员角色（带缓存）"""
        from app.crud import member as member_crud

        if ttl is None:
            ttl = self.default_ttl

        cache_key = self._make_member_cache_key(study_id, user_id)

        if cache_key in self._member_role_cache:
            cached_role, timestamp = self._member_role_cache[cache_key]
            if not self._is_expired(timestamp, ttl):
                return cached_role

        membership = await member_crud.get_member(db, study_id, user_id)
        role = membership.role_in_study if membership and membership.is_active else None

        self._member_role_cache[cache_key] = (role, time.time())
        return role

    def invalidate_project_permissions(self, study_id: uuid.UUID) -> None:
        cache_key = self._make_project_cache_key(study_id)
        self._project_permissions_cache.pop(cache_key, None)

    def invalidate_member_role(self, study_id: uuid.UUID, user_id: uuid.UUID) -> None:
        cache_key = self._make_member_cache_key(study_id, user_id)
        self._member_role_cache.pop(cache_key, None)

    def invalidate_all_member_roles(self, study_id: uuid.UUID) -> None:
        keys_to_delete = [
            key for key in self._member_role_cache.keys()
            if key.startswith(f"member_role:{study_id}:")
        ]
        for key in keys_to_delete:
            del self._member_role_cache[key]

    def clear_all(self) -> None:
        self._project_permissions_cache.clear()
        self._member_role_cache.clear()

    def get_cache_stats(self) -> dict[str, Any]:
        return {
            "project_permissions_count": len(self._project_permissions_cache),
            "member_role_count": len(self._member_role_cache),
            "total_count": len(self._project_permissions_cache) + len(self._member_role_cache),
        }


_permission_cache: PermissionCache | None = None


def get_permission_cache() -> PermissionCache:
    global _permission_cache
    if _permission_cache is None:
        _permission_cache = PermissionCache()
    return _permission_cache


def set_permission_cache(cache: PermissionCache) -> None:
    global _permission_cache
    _permission_cache = cache