from datetime import timedelta, datetime
from typing import Annotated
from fastapi import APIRouter, Depends
from pydantic import BaseModel
from passlib.context import CryptContext
from sqlalchemy.orm import Session
from starlette import status
from fastapi.security import OAuth2PasswordRequestForm
from jose import jwt

from models import User
from database import SessionLocal

router = APIRouter()

SECRET_KEY = '3b004eeae34b43bd05226f210d9bdc2ad99abdd3c52bf32802906085b762ff55'
ALGORITHM = 'HS256'

bcrypt_context = CryptContext(schemes=['bcrypt'], deprecated='auto')


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


db_dependency = Annotated[Session, Depends(get_db)]


def authenticate_user(username: str, password: str, db):
    user = db.query(User).filter(User.username == username).first()
    if not user:
        return False
    if not bcrypt_context.verify(password, user.password):
        return False
    return user


def create_access_token(username: str, user_id: int, expires_delta: timedelta):
    encode = {'sub': username, 'id': user_id}
    expire = datetime.now() + expires_delta
    encode.update({'exp': expire})

    return jwt.encode(encode, SECRET_KEY, ALGORITHM)


class CreateUser(BaseModel):
    username: str
    email: str
    password: str


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


@router.post('/auth/create', status_code=status.HTTP_201_CREATED)
async def create_user(db: db_dependency, data: CreateUser):
    create_user_model = User(
        username=data.username,
        email=data.email,
        password=bcrypt_context.hash(data.password),
        role='admin'
    )

    db.add(create_user_model)
    db.commit()


@router.post('/auth/token', status_code=status.HTTP_200_OK, response_model=Token)
async def get_token(
        form_data: Annotated[OAuth2PasswordRequestForm, Depends()],
        db: db_dependency
):
    user = authenticate_user(form_data.username, form_data.password, db)
    if not user:
        return "authentication failed"

    token = create_access_token(user.username, user.id, timedelta(minutes=20))
    return {'access_token': token, 'token_type': 'bearer'}