app.py

import gradio as gr
import torch
from transformers import AutoTokenizer, AutoModelForSequenceClassification
import logging
import numpy as np

# Configure logging
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

# Model configuration
MODEL_NAME = "cybersectony/phishing-email-detection-distilbert_v2.4.1"

# Global variables for model and tokenizer
tokenizer = None
model = None

def load_model():
    """Load the model and tokenizer with error handling"""
    global tokenizer, model
    try:
        logger.info("Loading model and tokenizer...")
        tokenizer = AutoTokenizer.from_pretrained(MODEL_NAME)
        model = AutoModelForSequenceClassification.from_pretrained(MODEL_NAME)
        
        # Debug: Print model configuration
        logger.info(f"Model config: {model.config}")
        logger.info(f"Number of labels: {model.config.num_labels}")
        if hasattr(model.config, 'id2label'):
            logger.info(f"Label mapping: {model.config.id2label}")
        
        # Test model with simple input to check if it's working
        test_input = "Hello world"
        inputs = tokenizer(test_input, return_tensors="pt", truncation=True, max_length=512)
        with torch.no_grad():
            outputs = model(**inputs)
            test_probs = torch.nn.functional.softmax(outputs.logits, dim=-1)
            logger.info(f"Test probabilities: {test_probs[0].tolist()}")
        
        logger.info("Model loaded successfully!")
        return True
    except Exception as e:
        logger.error(f"Error loading model: {e}")
        return False

def get_colored_bar(percentage, label):
    """Create colored progress bar based on percentage and label type"""
    # Determine color based on percentage and label
    if "phishing" in label.lower() or "suspicious" in label.lower():
        # Red scale for dangerous content
        if percentage >= 70:
            color = "🟥"  # High danger - red
        elif percentage >= 40:
            color = "🟠"  # Medium danger - orange  
        else:
            color = "🟡"  # Low danger - yellow
    else:
        # Green scale for legitimate content
        if percentage >= 70:
            color = "🟢"  # High confidence - green
        elif percentage >= 40:
            color = "🟡"  # Medium confidence - yellow
        else:
            color = "⚪"  # Low confidence - white
    
    # Create bar (scale to 20 characters)
    bar_length = max(1, int(percentage / 5))  # Ensure at least 1 if percentage > 0
    bar = color * bar_length + "⚪" * (20 - bar_length)
    
    return bar

def predict_email(email_text):
    """
    Enhanced prediction function with proper model output handling
    """
    # Input validation
    if not email_text or not email_text.strip():
        return "⚠️ **Error**: Please enter some email text to analyze."
    
    if len(email_text.strip()) < 5:
        return "⚠️ **Warning**: Email text too short for reliable analysis."
    
    # Check if model is loaded
    if tokenizer is None or model is None:
        if not load_model():
            return "❌ **Error**: Failed to load the model."
    
    try:
        # Preprocess and tokenize
        inputs = tokenizer(
            email_text,
            return_tensors="pt",
            truncation=True,
            max_length=512,
            padding=True
        )
        
        # Get prediction with proper handling
        with torch.no_grad():
            outputs = model(**inputs)
            # Apply temperature scaling to prevent overconfidence
            temperature = 1.5
            scaled_logits = outputs.logits / temperature
            predictions = torch.nn.functional.softmax(scaled_logits, dim=-1)
        
        # Get probabilities
        probs = predictions[0].tolist()
        
        # Log raw outputs for debugging
        logger.info(f"Raw logits: {outputs.logits[0].tolist()}")
        logger.info(f"Scaled probabilities: {probs}")
        
        # Get proper labels from model config or use fallback
        if hasattr(model.config, 'id2label') and model.config.id2label:
            labels = {model.config.id2label[i]: probs[i] for i in range(len(probs))}
        else:
            # Fallback - check the actual model output dimension
            if len(probs) == 2:
                labels = {
                    "Legitimate Email": probs[0],
                    "Phishing Email": probs[1]
                }
            elif len(probs) == 4:
                labels = {
                    "Legitimate Email": probs[0],
                    "Phishing Email": probs[1],
                    "Suspicious Content": probs[2],
                    "Spam Email": probs[3]
                }
            else:
                # Generic labels
                labels = {f"Class {i}": probs[i] for i in range(len(probs))}
        
        # Check if model is giving reasonable outputs
        prob_variance = np.var(probs)
        max_prob = max(probs)
        
        # If variance is too low, the model might not be working properly
        if prob_variance < 0.01 and max_prob > 0.99:
            logger.warning("Model showing signs of overconfidence or poor calibration")
            # Apply smoothing
            smoothed_probs = [(p * 0.8 + 0.2/len(probs)) for p in probs]
            labels = {list(labels.keys())[i]: smoothed_probs[i] for i in range(len(smoothed_probs))}
        
        # Find prediction
        max_label = max(labels.items(), key=lambda x: x[1])
        
        # Determine risk level and emoji
        confidence = max_label[1]
        prediction_name = max_label[0]
        
        if any(word in prediction_name.lower() for word in ['phishing', 'suspicious', 'spam']):
            if confidence > 0.8:
                risk_emoji = "🚨"
                risk_level = "HIGH RISK"
            elif confidence > 0.6:
                risk_emoji = "⚠️"
                risk_level = "MEDIUM RISK"
            else:
                risk_emoji = "⚡"
                risk_level = "LOW RISK"
        else:
            if confidence > 0.8:
                risk_emoji = "✅"
                risk_level = "SAFE"
            elif confidence > 0.6:
                risk_emoji = "✅"
                risk_level = "LIKELY SAFE"
            else:
                risk_emoji = "❓"
                risk_level = "UNCERTAIN"
        
        # Format output with colored bars
        result = f"{risk_emoji} **{risk_level}**\n\n"
        result += f"**Primary Classification**: {prediction_name}\n"
        result += f"**Confidence**: {confidence:.1%}\n\n"
        result += f"**Detailed Analysis**:\n"
        
        # Sort by probability and add colored bars
        for label, prob in sorted(labels.items(), key=lambda x: x[1], reverse=True):
            percentage = prob * 100
            colored_bar = get_colored_bar(percentage, label)
            result += f"{label}: {percentage:.1f}% {colored_bar}\n"
        
        # Add debug info
        result += f"\n**Debug Info**:\n"
        result += f"Model Variance: {prob_variance:.4f}\n"
        result += f"Raw Probabilities: {[f'{p:.3f}' for p in probs]}\n"
        
        # Add recommendations based on actual classification
        if any(word in prediction_name.lower() for word in ['phishing', 'suspicious']) and confidence > 0.6:
            result += f"\n⚠️ **Recommendation**: This email shows signs of being malicious. Avoid clicking links or providing personal information."
        elif 'spam' in prediction_name.lower():
            result += f"\n🗑️ **Recommendation**: This appears to be spam. Consider deleting or marking as junk."
        elif confidence > 0.7:
            result += f"\n✅ **Recommendation**: This email appears legitimate, but always remain vigilant."
        else:
            result += f"\n❓ **Recommendation**: Classification uncertain. Exercise caution and verify sender if needed."
            
        return result
        
    except Exception as e:
        logger.error(f"Error during prediction: {e}", exc_info=True)
        return f"❌ **Error**: Analysis failed - {str(e)}"

# Example emails for testing
example_legitimate = """Dear Customer,

Thank you for your recent purchase from TechStore. Your order #ORD-2024-001234 has been successfully processed.

Order Details:
- Product: Wireless Headphones  
- Amount: $79.99
- Estimated delivery: 3-5 business days

You will receive a tracking number once your item ships.

Best regards,
TechStore Customer Service"""

example_phishing = """URGENT SECURITY ALERT!!!

Your account has been COMPROMISED! Immediate action required!

Click here NOW to secure your account: http://fake-security-site.malicious.com/urgent-verify

WARNING: You have only 24 hours before your account is permanently suspended!

This is your FINAL notice - act immediately!

Security Department"""

example_neutral = """Hi team,

Hope everyone is doing well. Just wanted to remind you about the meeting scheduled for tomorrow at 2 PM in the conference room.

Please bring your project updates and any questions you might have.

Thanks,
Sarah"""

# Load model on startup
load_model()

# Create enhanced Gradio interface
with gr.Blocks(title="PhishGuardian AI", theme=gr.themes.Soft()) as iface:
    gr.Markdown("""
    # 🛡️ PhishGuardian AI - Enhanced Detection
    
    Advanced phishing email detection with colored risk indicators and improved model handling.
    """)
    
    with gr.Row():
        with gr.Column(scale=2):
            email_input = gr.Textbox(
                lines=10,
                placeholder="Paste your email content here for analysis...",
                label="📧 Email Content",
                info="Enter the complete email text for comprehensive analysis"
            )
            
            with gr.Row():
                analyze_btn = gr.Button("🔍 Analyze Email", variant="primary", size="lg")
                clear_btn = gr.Button("🗑️ Clear", variant="secondary")
        
        with gr.Column(scale=2):
            output = gr.Textbox(
                label="🛡️ Security Analysis Results",
                lines=20,
                interactive=False,
                show_copy_button=True
            )
    
    # Example section with better examples
    gr.Markdown("### 📝 Test Examples")
    with gr.Row():
        legit_btn = gr.Button("✅ Legitimate Email", size="sm")
        phish_btn = gr.Button("🚨 Phishing Email", size="sm") 
        neutral_btn = gr.Button("📄 Neutral Text", size="sm")
    
    # Event handlers
    analyze_btn.click(predict_email, inputs=email_input, outputs=output)
    clear_btn.click(lambda: ("", ""), outputs=[email_input, output])
    
    legit_btn.click(lambda: example_legitimate, outputs=email_input)
    phish_btn.click(lambda: example_phishing, outputs=email_input)
    neutral_btn.click(lambda: example_neutral, outputs=email_input)
    
    # Footer with model info
    gr.Markdown("""
    ---
    **🔧 Model**: cybersectony/phishing-email-detection-distilbert_v2.4.1  
    **🎯 Features**: Temperature scaling, colored risk bars, enhanced debugging  
    **🏛️ Institution**: University of Dar es Salaam (UDSM)
    """)

if __name__ == "__main__":
    iface.launch(
        share=True,
        server_name="0.0.0.0", 
        server_port=7860,
        show_error=True,
        debug=True
    )