import jwt
import datetime
from flask import current_app


class AuthService:
    @staticmethod
    def login(username, password):
        """
        Login method that checks for specific credentials and returns a JWT token
        """
        # Define valid credentials for testing
        valid_credentials = {
            "digifiuser": "digifipass",
            "admin": "admin123",
            "test": "test123"
        }

        # Check if the provided credentials are valid
        if username in valid_credentials and password == valid_credentials[username]:
            # Generate JWT token with 15 minutes expiration
            payload = {
                'sub': username,  # Subject (typically user ID)
                'iat': datetime.datetime.utcnow(),  # Issued at
                'exp': datetime.datetime.utcnow() + datetime.timedelta(minutes=15),  # Expiration (15 minutes)
                'role': 'admin' if username == 'admin' else 'user'  # Role based on username
            }

            # Get the secret key from config
            secret_key = current_app.config.get('JWT_SECRET_KEY', 'default-secret-key')

            # Generate the token
            token = jwt.encode(payload, secret_key, algorithm='HS256')

            # Return the token and user info
            return {
                'jwt_token': token,
                'user': {
                    'username': username,
                    'role': 'admin' if username == 'admin' else 'user'
                },
                'expires_in': 900  # 15 minutes in seconds
            }
        else:
            # Return error for invalid credentials
            return {
                'error': 'Invalid credentials',
                'message': 'The username or password is incorrect'
            }, 401

    @staticmethod
    def verify_token(token):
        """
        Verify the JWT token
        """
        try:
            # Get the secret key from config
            secret_key = current_app.config.get('JWT_SECRET_KEY', 'default-secret-key')

            # Decode the token
            payload = jwt.decode(token, secret_key, algorithms=['HS256'])
            return payload
        except jwt.ExpiredSignatureError:
            return None  # Token has expired
        except jwt.InvalidTokenError:
            return None  # Invalid token