from datetime import datetime, timedelta
from typing import Optional
from jose import JWTError, jwt
from passlib.context import CryptContext
from fastapi import Depends, HTTPException, status
from fastapi.security import OAuth2PasswordBearer
from pydantic import BaseModel
from src.core.config import settings

# Configuration for JWT
SECRET_KEY = settings.JWT_SECRET_KEY
ALGORITHM = settings.JWT_ALGORITHM
ACCESS_TOKEN_EXPIRE_MINUTES = settings.JWT_EXPIRES

# Password hashing context
pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")

# OAuth2 password bearer
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")


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


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


# Functions for password hashing and verification
def verify_password(plain_password: str, hashed_password: str) -> bool:
    return pwd_context.verify(plain_password, hashed_password)


def get_password_hash(password: str) -> str:
    return pwd_context.hash(password)


# Functions for generating and decoding JWT tokens
def create_access_token(data: dict, expires_delta: Optional[timedelta] = None) -> str:
    to_encode = data.copy()
    if expires_delta:
        expire = datetime.utcnow() + expires_delta
    else:
        expire = datetime.utcnow() + timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES)
    to_encode.update({"exp": expire})
    encoded_jwt = jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)
    return encoded_jwt


async def get_current_user(token: str = Depends(oauth2_scheme)) -> TokenData:
    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Could not validate credentials",
        headers={"WWW-Authenticate": "Bearer"},
    )
    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        username: str = payload.get("sub")
        if username is None:
            raise credentials_exception
        token_data = TokenData(username=username)
    except JWTError:
        raise credentials_exception
    return token_data


async def get_current_active_user(
    current_user: TokenData = Depends(get_current_user),
) -> TokenData:
    # You can add more checks here, such as checking if the user is active
    return current_user