from datetime import datetime, timedelta

from fastapi import APIRouter, Depends, HTTPException, status
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from jose import jwt
from pydantic import BaseModel

from ..config import (ACCESS_TOKEN_EXPIRE_MINUTES, ALGORITHM, CRYPT_CONTEXT,
                      SECRET_KEY)
from ..db import User

router = APIRouter(prefix="/auth")
SCHEME = OAuth2PasswordBearer(
    tokenUrl=f".{router.prefix}/token"
)


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


def create_access_token(data: dict, expires_delta: timedelta | None = None):
    to_encode = data.copy()
    if expires_delta is None:
        expires_delta = timedelta(minutes=15)

    to_encode.update({"exp": datetime.utcnow() + expires_delta})
    return jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)


@router.post("/token", response_model=Token)
async def login_for_access_token(
        form_data: OAuth2PasswordRequestForm = Depends()
):
    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Could not validate credentials",
        headers={"WWW-Authenticate": "Bearer"},
    )

    user = User.get_by_name(form_data.username)
    if user is None:
        CRYPT_CONTEXT.dummy_verify()
        raise credentials_exception

    if not user.verify(form_data.password):
        raise credentials_exception

    access_token = create_access_token(
        data={"sub": user.name},
        expires_delta=timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES),
    )
    return {"access_token": access_token, "token_type": "bearer"}