from iti.applications.extensions import eventbus
from iti_system.events.names import (
    UserEvents,
    UserRelEvents,
    RoleEvents,
    MenuEvents,
    RoleRelEvents,
)
from iti_system.models import User, Role, SysMenu, sys_role_menu, sys_user_role
from iti.applications.extensions import cache_simple, db
from sqlalchemy import select, distinct


class UserCacheEventHandler:
    """
    用户数据缓存 事件处理器
    """

    def __init__(self, app=None):
        if app:
            self.init_app(app)

    def init_app(self, app):
        self.app = app
        self._register_handlers()

    def _register_handlers(self):
        """
        注册事件处理器
        """

        # 用户
        eventbus.register_handler(
            UserEvents.USER_UPDATED,
            self._handle_user_updated,
            order=-1,
            async_mode=True,
        )
        eventbus.register_handler(
            UserEvents.USER_DELETED,
            self._handle_user_deleted,
            order=-1,
            async_mode=True,
        )
        eventbus.register_handler(
            UserEvents.USER_AUTH_REFRESHED,
            self._handle_user_updated,
            order=-1,
            async_mode=True,
        )
        eventbus.register_handler(
            UserEvents.USER_LOGOUT,
            self._handle_user_updated,
            order=-1,
            async_mode=True,
        )
        eventbus.register_handler(
            UserEvents.USER_PASSWORD_UPDATED,
            self._handle_user_updated,
            order=-1,
            async_mode=True,
        )

        # 用户关系
        eventbus.register_handler(
            UserRelEvents.USER_ROLES_UPDATED,
            self._handle_user_updated,
            order=-1,
            async_mode=True,
        )
        eventbus.register_handler(
            UserRelEvents.USER_DEPTS_UPDATED,
            self._handle_user_updated,
            order=-1,
            async_mode=True,
        )

        # 角色删除
        eventbus.register_handler(
            RoleEvents.ROLE_DELETED,
            self._handle_role_changed,
            order=-1,
            async_mode=True,
        )
        eventbus.register_handler(
            RoleRelEvents.ROLE_MENUS_UPDATED.value,
            self._handle_role_changed,
            order=-1,
            async_mode=True,
        )

        # 菜单
        eventbus.register_handler(
            MenuEvents.MENU_UPDATED,
            self._handle_menu_updated,
            order=-1,
            async_mode=True,
        )
        eventbus.register_handler(
            MenuEvents.MENU_DELETED,
            self._handle_menu_deleted,
            order=-1,
            async_mode=True,
        )

    def _invalidate_user_cache(self, user_id):
        """
        清理用户缓存
        """

        if user_id:
            cache_simple.delete(f"user_{user_id}")

    def _handle_user_updated(self, user: User):
        self._invalidate_user_cache(user.id)

    def _handle_user_deleted(self, user_id):
        self._invalidate_user_cache(user_id)

    def _handle_role_changed(self, role: Role):
        # 角色关联的用户缓存都应该被删除
        if role.users:
            for user in role.users:
                self._invalidate_user_cache(user.id)

    def _handle_menu_updated(self, menu: SysMenu, old_menu: SysMenu):
        # 若菜单更新了权限字段
        if old_menu and old_menu.auth_code != menu.auth_code:
            # 与该菜单相关的角色的用户缓存都应该被删除
            # 查询菜单相关的角色关联的所有用户ID
            self._handle_menu_deleted(menu)

    def _handle_menu_deleted(self, menu: SysMenu):
        # 与该菜单相关的角色的用户缓存都应该被删除
        # 查询菜单相关的角色关联的所有用户ID
        user_ids = db.session.scalars(
            select(distinct(sys_user_role.c.user_id))
            .join(sys_user_role, sys_role_menu.c.role_id == sys_user_role.c.role_id)
            .where(sys_role_menu.c.menu_id == menu.id)
        ).all()
        for user_id in user_ids:
            self._invalidate_user_cache(user_id)