import uuid

from datetime import datetime, timedelta
from typing import List, Optional

from fastapi import Depends, HTTPException, Security, status
from fastapi.security import OAuth2PasswordBearer, SecurityScopes
from jose import jwt
from jose.exceptions import ExpiredSignatureError
from jwt import PyJWTError
from pydantic import BaseModel, ValidationError
from sqlalchemy.orm import Session

from ..core.config import settings
from ..db.session import SessionLocal
from ..models.auth import Client
from ..models.auth import User as UserModel

# to get a string like this run:
from ..schemas.auth import UserToken


oauth2_scheme = OAuth2PasswordBearer(tokenUrl="/token", scopes={})


class Token(BaseModel):
    access_token: str
    token_type: str


class TokenData(BaseModel):
    username: str = None
    scopes: List[str] = []


def f7(seq):
    seen = set()
    seen_add = seen.add
    return [x for x in seq if not (x in seen or seen_add(x))]


# Dependency
def get_db():
    try:
        db = SessionLocal()
        yield db
    finally:
        db.close()


def create_access_token(*, data: dict, expires_delta: timedelta = None):
    to_encode = data.copy()
    if expires_delta:
        expire = datetime.utcnow() + expires_delta
    else:
        expire = datetime.utcnow() + timedelta(minutes=15)
    to_encode.update({"exp": expire})
    encoded_jwt = jwt.encode(
        to_encode, settings.SECRET_KEY, algorithm=settings.ALGORITHM
    )
    return encoded_jwt


def get_user(username: str, id_: str, locked_out: bool, scopes: List[str]) -> UserToken:
    return UserToken(
        id_=uuid.UUID(id_),
        name=username,
        locked_out=locked_out,
        password="",
        permissions=scopes,
    )


def authenticate_user(
    username: str, password: str, client_id: Optional[int], otp: int, db: Session
) -> Optional[UserModel]:
    user = UserModel.auth(username, password, db)
    return user


def client_allowed(
    user: UserModel, client_id: int, otp: Optional[int] = None, db: Session = None
) -> (bool, int):
    client = (
        db.query(Client).filter(Client.code == client_id).first() if client_id else None
    )
    allowed = "clients" in set(
        [p.name.replace(" ", "-").lower() for r in user.roles for p in r.permissions]
    )
    if allowed:
        return True, 0
    elif client is None:
        client = Client.create(db)
        return False, client.code
    elif client.enabled:
        return True, client.code
    elif client.otp == otp:
        client.otp = None
        client.enabled = True
        return True, client.code
    else:
        return False, client.code


async def get_current_user(
    security_scopes: SecurityScopes,
    token: str = Depends(oauth2_scheme),
) -> UserToken:
    if security_scopes.scopes:
        authenticate_value = f'Bearer scope="{security_scopes.scope_str}"'
    else:
        authenticate_value = f"Bearer"
    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Could not validate credentials",
        headers={"WWW-Authenticate": authenticate_value},
    )
    try:
        payload = jwt.decode(
            token, settings.SECRET_KEY, algorithms=[settings.ALGORITHM]
        )
        username: str = payload.get("sub")
        if username is None:
            raise credentials_exception
        token_scopes = payload.get("scopes", [])
        token_data = TokenData(scopes=token_scopes, username=username)
    except (PyJWTError, ValidationError, ExpiredSignatureError):
        raise credentials_exception
    user = get_user(
        username=token_data.username,
        id_=payload.get("userId", None),
        locked_out=payload.get("lockedOut", True),
        scopes=token_scopes,
    )
    if user is None:
        raise credentials_exception
    for scope in security_scopes.scopes:
        if scope not in token_data.scopes:
            raise HTTPException(
                status_code=status.HTTP_401_UNAUTHORIZED,
                detail="Not enough permissions",
                headers={"WWW-Authenticate": authenticate_value},
            )
    return user


async def get_current_active_user(
    current_user: UserToken = Security(get_current_user, scopes=["authenticated"])
) -> UserToken:
    if current_user.locked_out:
        raise HTTPException(status_code=400, detail="Inactive user")
    return current_user