from datetime import datetime, timedelta, timezone
from typing import Dict
from jose import jwt, JWTError
from infra.config.app_settings import app_settings
from fastapi import Depends, HTTPException
from fastapi.security import OAuth2PasswordBearer
from starlette.status import HTTP_401_UNAUTHORIZED


class TokenManager:
    def __init__(self):
        self.secret_key = app_settings.JWT_SECRET_KEY
        self.algorithm = "HS256"
        self.access_token_expire_minutes = app_settings.ACCESS_TOKEN_EXPIRE_MINUTES
        self.refresh_token_expire_days = app_settings.REFRESH_TOKEN_EXPIRE_DAYS

    def create_access_token(self, subject: Dict[str, str]) -> str:
        """
        Generates an access token with a short expiration time.
        """
        expire = datetime.now(timezone.utc) + timedelta(
            minutes=self.access_token_expire_minutes
        )
        to_encode = subject.copy()
        to_encode.update({"exp": expire})
        return jwt.encode(to_encode, self.secret_key, algorithm=self.algorithm)

    def create_refresh_token(self, subject: Dict[str, str]) -> str:
        """
        Generates a refresh token with a longer expiration time.
        """
        expire = datetime.now(timezone.utc) + timedelta(
            days=self.refresh_token_expire_days
        )
        to_encode = subject.copy()
        to_encode.update({"exp": expire})
        return jwt.encode(to_encode, self.secret_key, algorithm=self.algorithm)

    def decode_token(self, token: str) -> Dict:
        """
        Decodes a JWT token and returns the payload.
        """
        try:
            payload = jwt.decode(token, self.secret_key, algorithms=[self.algorithm])
            return payload
        except JWTError:
            raise ValueError("Invalid token")

    def verify_refresh_token(self, token: str) -> bool:
        """
        Verifies a refresh token to ensure it is valid and not expired.
        """
        try:
            payload = self.decode_token(token)
            return True
        except ValueError:
            return False

    def refresh_access_token(self, refresh_token: str, subject: Dict[str, str]) -> str:
        """
        Verifies the refresh token and creates a new access token.
        """
        if self.verify_refresh_token(refresh_token):
            return self.create_access_token(subject)
        else:
            raise ValueError("Invalid refresh token")

    async def get_current_user(
        self, token: str = Depends(OAuth2PasswordBearer(tokenUrl="token"))
    ) -> Dict:
        """
        Extract and validate user information from the JWT token.
        """
        try:
            payload = self.decode_token(token)  # Decode JWT token
            return payload
        except ValueError:
            raise HTTPException(
                status_code=HTTP_401_UNAUTHORIZED, detail="Invalid or expired token"
            )