from __future__ import annotations

import secrets

from typing import Any

from fastapi import Depends, HTTPException, Request

from Groups import AdminGroupName, GetGroupsForUser, GuestGroupName, IsUserInGroup
from Users import GetUser


ActiveSessions: dict[str, str] = {}

SessionCookieName = "SaraViewSession"

GuestUser: dict[str, Any] = {
    "Username": None,
    "IsAdmin": False,
    "IsGuest": True,
    "Groups": [GuestGroupName],
    "Colour": "Purple",
}


def CreateSession(Username: str) -> str:
    Token = secrets.token_urlsafe(32)
    ActiveSessions[Token] = Username
    return Token


def DeleteSession(Token: str) -> None:
    ActiveSessions.pop(Token, None)


def _BuildUserRecord(Username: str, User: dict[str, Any]) -> dict[str, Any]:
    UserGroups = GetGroupsForUser(Username)

    if GuestGroupName not in UserGroups:
        UserGroups = [*UserGroups, GuestGroupName]

    return {
        "Username": Username,
        "IsAdmin": AdminGroupName in UserGroups,
        "IsGuest": False,
        "Groups": UserGroups,
        "Colour": User.get("Colour", "Purple"),
    }


def GetCurrentUser(request: Request) -> dict[str, Any]:
    Token = request.cookies.get(SessionCookieName)
    Username = ActiveSessions.get(Token) if Token else None

    if Username is None:
        raise HTTPException(status_code=401, detail="Not logged in.")

    User = GetUser(Username)

    if User is None:
        raise HTTPException(status_code=401, detail="Session user no longer exists.")

    return _BuildUserRecord(Username, User)


def GetCurrentUserOrGuest(request: Request) -> dict[str, Any]:
    Token = request.cookies.get(SessionCookieName)
    Username = ActiveSessions.get(Token) if Token else None

    if Username is None:
        return dict(GuestUser)

    User = GetUser(Username)

    if User is None:
        return dict(GuestUser)

    return _BuildUserRecord(Username, User)


def RequireAdmin(CurrentUser: dict = Depends(GetCurrentUser)) -> dict:
    if not CurrentUser.get("IsAdmin"):
        raise HTTPException(status_code=403, detail="Admin access required.")

    return CurrentUser