"""Deal with user sessions"""
from uuid import UUID, uuid4
from typing import Any, Optional, TypedDict

from flask import request, session
from pymonad.either import Left, Right, Either


class UserDetails(TypedDict):
    """Session information relating specifically to the user."""
    user_id: UUID
    name: str
    email: str
    token: Either
    logged_in: bool


class SessionInfo(TypedDict):
    """All Session information we save."""
    session_id: UUID
    user: UserDetails
    anon_id: UUID
    user_agent: str
    ip_addr: str
    masquerade: Optional[UserDetails]
    auth_server_jwks: Optional[dict[str, Any]]


__SESSION_KEY__ = "GN::uploader::session_info" # Do not use this outside this module!!


def clear_session_info():
    """Clears the session."""
    session.pop(__SESSION_KEY__)


def save_session_info(sess_info: SessionInfo) -> SessionInfo:
    """Save `session_info`."""
    # T0d0: if it is an existing session, verify that certain important security
    #       bits have not changed before saving.
    # old_session_info = session.get(__SESSION_KEY__)
    # if bool(old_session_info):
    #     if old_session_info["user_agent"] == request.headers.get("User-Agent"):
    #         session[__SESSION_KEY__] = sess_info
    #         return sess_info
    #     # request session verification
    #     return verify_session(sess_info)
    # New session
    session[__SESSION_KEY__] = sess_info
    return sess_info


def session_info() -> SessionInfo:
    """Retrieve the session information"""
    anon_id = uuid4()
    return save_session_info(
        session.get(__SESSION_KEY__, {
            "session_id": uuid4(),
            "user": {
                "user_id": anon_id,
                "name": "Anonymous User",
                "email": "anon@ymous.user",
                "token": Left("INVALID-TOKEN"),
                "logged_in": False
            },
            "anon_id": anon_id,
            "user_agent": request.headers.get("User-Agent"),
            "ip_addr": request.environ.get("HTTP_X_FORWARDED_FOR",
                                           request.remote_addr),
            "masquerading": None
        }))


def set_user_token(token: str) -> SessionInfo:
    """Set the user's token."""
    info = session_info()
    return save_session_info({
        **info, "user": {**info["user"], "token": Right(token)}})#type: ignore[misc]


def set_user_details(userdets: UserDetails) -> SessionInfo:
    """Set the user details information"""
    return save_session_info({**session_info(), "user": userdets})#type: ignore[misc]

def user_details() -> UserDetails:
    """Retrieve user details."""
    return session_info()["user"]

def user_token() -> Either:
    """Retrieve the user token."""
    return session_info()["user"]["token"]