# patent_8_privacy_validation.py

import hashlib
import random
import logging
import numpy as np  # For numerical operations, especially for confidence scores

# Configure logging (important for auditing and debugging)
logging.basicConfig(level=logging.INFO, format='%(asctime)s - %(levelname)s - %(message)s')

class PrivacyPreservingValidator:
    """
    Validates AI model outputs without exposing sensitive data, using data masking,
    tokenization, differential privacy, and secure confidence scoring.
    """

    def __init__(self, epsilon=1.0, delta=1e-5):  # Differential privacy parameters
        """
        Initializes the validator.

        Args:
            epsilon (float):  Privacy parameter for differential privacy.  Lower values mean more privacy.
            delta (float):  Privacy parameter for differential privacy.  Represents the probability of a privacy breach.
        """
        self.epsilon = epsilon
        self.delta = delta
        self.tokenizer = self.create_tokenizer() # Initialize tokenizer
        self.salt = self.generate_salt()       # Add a salt for hashing to prevent rainbow table attacks

    def create_tokenizer(self):
        """
        Creates a simple tokenizer (replace with a more sophisticated one if needed).
        For this example, it's a dictionary mapping values to tokens.  In real applications,
        consider using libraries like scikit-learn's CountVectorizer or more advanced NLP tokenizers.
        """
        # Example token vocabulary (expand as needed)
        vocabulary = {
            "positive": 1,
            "negative": 2,
            "neutral": 3,
            "true": 4,
            "false": 5,
            "high": 6,
            "low": 7,
            "medium": 8,
        }
        return vocabulary

    def generate_salt(self):
        """
        Generates a random salt for hashing.  This is crucial for security.
        """
        return str(random.randint(100000, 999999))  # Generate a random 6-digit number as a string

    def mask_data(self, data):
        """
        Masks sensitive data using techniques like generalization or suppression.
        This is a placeholder; implement domain-specific masking logic here.

        Args:
            data (dict): The data to be masked (e.g., a dictionary of key-value pairs).

        Returns:
            dict: The masked data.
        """
        masked_data = {}
        for key, value in data.items():
            # Example: Replace email addresses with a generic placeholder
            if "email" in key.lower():
                masked_data[key] = "[EMAIL_REDACTED]"
            # Example: Replace numerical values with a range
            elif isinstance(value, (int, float)):
                masked_data[key] = "[NUMERICAL_VALUE]" # Or a range, e.g., "[0-100]"
            else:
                masked_data[key] = value  # Keep other values as they are (for now)

        logging.info(f"Data masked: {masked_data}") # Log the masked data (without sensitive parts!)
        return masked_data


    def tokenize_data(self, data):
        """
        Tokenizes the data using the defined tokenizer.

        Args:
            data (dict): The data to be tokenized.

        Returns:
            dict: The tokenized data.
        """
        tokenized_data = {}
        for key, value in data.items():
            if isinstance(value, str):
                try:
                    tokenized_data[key] = self.tokenizer[value.lower()]  # Convert to lowercase for consistency
                except KeyError:
                    # Handle unknown tokens (e.g., assign a special "unknown" token)
                    tokenized_data[key] = 0  # Or raise an error, depending on your requirements
                    logging.warning(f"Unknown token: {value}") # Log unknown tokens
            else:
                tokenized_data[key] = value  # Keep non-string values as they are
        logging.info(f"Data tokenized: {tokenized_data}")
        return tokenized_data

    def hash_data(self, data):
        """
        Hashes the data using SHA-256.  Includes a salt to prevent rainbow table attacks.

        Args:
            data (dict): The data to be hashed.

        Returns:
            str: The hexadecimal representation of the hash.
        """
        data_str = str(data) + self.salt  # Combine data with salt
        hashed_data = hashlib.sha256(data_str.encode('utf-8')).hexdigest()
        logging.debug(f"Data hashed (first 10 characters): {hashed_data[:10]}...") # Log a truncated hash for debugging
        return hashed_data


    def privacy_safe_confidence_score(self, confidence_score):
        """
        Calculates a privacy-safe confidence score using differential privacy.

        Args:
            confidence_score (float): The original confidence score (between 0 and 1).

        Returns:
            float: The differentially private confidence score.
        """
        # Implement Laplace mechanism for differential privacy
        sensitivity = 1.0  # Sensitivity of the confidence score (max change)
        beta = sensitivity / self.epsilon  # Parameter for Laplace distribution

        # Add Laplace noise
        noise = np.random.laplace(0, beta)
        private_score = confidence_score + noise

        # Clip the score to [0, 1]
        private_score = np.clip(private_score, 0, 1)

        logging.info(f"Original score: {confidence_score}, Private score: {private_score}")
        return private_score


    def validate_output(self, model_output, expected_output):
        """
        Validates the model output against the expected output in a privacy-preserving manner.

        Args:
            model_output (dict): The output from the AI model.
            expected_output (dict): The expected output for validation.

        Returns:
            bool: True if the validation is successful (based on hashed data), False otherwise.
        """
        # 1. Mask sensitive data
        masked_model_output = self.mask_data(model_output)
        masked_expected_output = self.mask_data(expected_output)

        # 2. Tokenize the masked data
        tokenized_model_output = self.tokenize_data(masked_model_output)
        tokenized_expected_output = self.tokenize_data(masked_expected_output)

        # 3. Hash the tokenized data
        hashed_model_output = self.hash_data(tokenized_model_output)
        hashed_expected_output = self.hash_data(tokenized_expected_output)

        # 4. Compare the hashes
        validation_result = hashed_model_output == hashed_expected_output
        logging.info(f"Validation result: {validation_result}")

        return validation_result

# Example usage:
if __name__ == "__main__":
    validator = PrivacyPreservingValidator(epsilon=0.5)

    # Example model output and expected output (containing sensitive data)
    model_output = {
        "prediction": "positive",
        "confidence": 0.85,
        "user_email": "test@example.com",
        "age": 30,
    }
    expected_output = {
        "prediction": "positive",
        "confidence": 0.90,
        "user_email": "test@example.com",  # Ideally, expected output would also be masked
        "age": 30,
    }

    # Validate the output
    is_valid = validator.validate_output(model_output, expected_output)
    print(f"Is validation successful? {is_valid}")

    # Example of privacy-safe confidence scoring
    original_confidence = model_output["confidence"]
    private_confidence = validator.privacy_safe_confidence_score(original_confidence)
    print(f"Original confidence: {original_confidence}, Private confidence: {private_confidence}")
