import enum
import uuid
from datetime import datetime, timedelta, timezone
from typing import Any, Final

from config import OIDC_ENABLED, ROMM_AUTH_SECRET_KEY
from exceptions.auth_exceptions import OAuthCredentialsException, UserDisabledException
from fastapi import HTTPException, status
from joserfc import jwt
from joserfc.errors import BadSignatureError
from joserfc.jwk import OctKey
from logger.logger import log
from passlib.context import CryptContext
from starlette.requests import HTTPConnection

ALGORITHM: Final = "HS256"
DEFAULT_OAUTH_TOKEN_EXPIRY: Final = timedelta(minutes=15)


class Scope(enum.StrEnum):
    ME_READ = "me.read"
    ME_WRITE = "me.write"
    ROMS_READ = "roms.read"
    ROMS_WRITE = "roms.write"
    ROMS_USER_READ = "roms.user.read"
    ROMS_USER_WRITE = "roms.user.write"
    PLATFORMS_READ = "platforms.read"
    PLATFORMS_WRITE = "platforms.write"
    ASSETS_READ = "assets.read"
    ASSETS_WRITE = "assets.write"
    FIRMWARE_READ = "firmware.read"
    FIRMWARE_WRITE = "firmware.write"
    COLLECTIONS_READ = "collections.read"
    COLLECTIONS_WRITE = "collections.write"
    USERS_READ = "users.read"
    USERS_WRITE = "users.write"
    TASKS_RUN = "tasks.run"


DEFAULT_SCOPES_MAP: Final = {
    Scope.ME_READ: "View your profile",
    Scope.ME_WRITE: "Modify your profile",
    Scope.ROMS_READ: "View ROMs",
    Scope.PLATFORMS_READ: "View platforms",
    Scope.ASSETS_READ: "View assets",
    Scope.ASSETS_WRITE: "Modify assets",
    Scope.FIRMWARE_READ: "View firmware",
    Scope.ROMS_USER_READ: "View user-rom properties",
    Scope.ROMS_USER_WRITE: "Modify user-rom properties",
    Scope.COLLECTIONS_READ: "View collections",
    Scope.COLLECTIONS_WRITE: "Modify collections",
}

WRITE_SCOPES_MAP: Final = {
    Scope.ROMS_WRITE: "Modify ROMs",
    Scope.PLATFORMS_WRITE: "Modify platforms",
    Scope.FIRMWARE_WRITE: "Modify firmware",
}

FULL_SCOPES_MAP: Final = {
    Scope.USERS_READ: "View users",
    Scope.USERS_WRITE: "Modify users",
    Scope.TASKS_RUN: "Run tasks",
}

DEFAULT_SCOPES: Final = list(DEFAULT_SCOPES_MAP.keys())
WRITE_SCOPES: Final = DEFAULT_SCOPES + list(WRITE_SCOPES_MAP.keys())
FULL_SCOPES: Final = WRITE_SCOPES + list(FULL_SCOPES_MAP.keys())


class AuthHandler:
    def __init__(self) -> None:
        self.pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")

    def verify_password(self, plain_password, hashed_password):
        return self.pwd_context.verify(plain_password, hashed_password)

    def get_password_hash(self, password):
        return self.pwd_context.hash(password)

    def authenticate_user(self, username: str, password: str):
        from handler.database import db_user_handler

        user = db_user_handler.get_user_by_username(username)
        if not user:
            return None

        if not self.verify_password(password, user.hashed_password):
            return None

        return user

    async def get_current_active_user_from_session(self, conn: HTTPConnection):
        from handler.database import db_user_handler

        issuer = conn.session.get("iss")
        if not issuer or issuer != "romm:auth":
            return None

        username = conn.session.get("sub")
        if not username:
            return None

        # Key exists therefore user is probably authenticated
        user = db_user_handler.get_user_by_username(username)
        if user is None or not user.enabled:
            conn.session.clear()
            log.error(
                "User '%s' %s",
                username,
                "not found" if user is None else "not enabled",
            )
            return None

        return user


class OAuthHandler:
    def __init__(self) -> None:
        pass

    def create_oauth_token(
        self, data: dict, expires_delta: timedelta = DEFAULT_OAUTH_TOKEN_EXPIRY
    ) -> str:
        to_encode = data.copy()
        expire = datetime.now(timezone.utc) + expires_delta
        to_encode.update({"exp": expire})

        return jwt.encode(
            {"alg": ALGORITHM}, to_encode, OctKey.import_key(ROMM_AUTH_SECRET_KEY)
        )

    async def get_current_active_user_from_bearer_token(self, token: str):
        from handler.database import db_user_handler

        try:
            payload = jwt.decode(token, OctKey.import_key(ROMM_AUTH_SECRET_KEY))
        except (BadSignatureError, ValueError) as exc:
            raise OAuthCredentialsException from exc

        issuer = payload.claims.get("iss")
        if not issuer or issuer != "romm:oauth":
            return None, None

        username = payload.claims.get("sub")
        if username is None:
            raise OAuthCredentialsException

        user = db_user_handler.get_user_by_username(username)
        if user is None:
            raise OAuthCredentialsException

        if not user.enabled:
            raise UserDisabledException

        return user, payload.claims


class OpenIDHandler:
    async def get_current_active_user_from_openid_token(self, token: Any):
        from handler.database import db_user_handler
        from models.user import Role, User

        if not OIDC_ENABLED:
            return None, None

        userinfo = token.get("userinfo")
        if userinfo is None:
            log.error("Userinfo is missing from token.")
            raise HTTPException(
                status_code=status.HTTP_400_BAD_REQUEST,
                detail="Userinfo is missing from token.",
            )

        email = userinfo.get("email")
        if email is None:
            log.error("Email is missing from token.")
            raise HTTPException(
                status_code=status.HTTP_400_BAD_REQUEST,
                detail="Email is missing from token.",
            )
        if userinfo.get("email_verified", None) is not True:
            log.error("Email is not verified.")
            raise HTTPException(
                status_code=status.HTTP_400_BAD_REQUEST,
                detail="Email is not verified.",
            )

        preferred_username = userinfo.get("preferred_username")

        user = db_user_handler.get_user_by_email(email)
        if user is None:
            log.info("User with email '%s' not found, creating new user", email)
            user = User(
                username=preferred_username,
                hashed_password=str(uuid.uuid4()),
                email=email,
                enabled=True,
                role=Role.VIEWER,
            )
            db_user_handler.add_user(user)

        if not user.enabled:
            raise UserDisabledException

        log.info("User successfully authenticated: %s", email)
        return user, userinfo