app.py

import gradio as gr
from transformers import pipeline
from datasets import load_dataset
import chromadb
from chromadb.config import Settings

print("="*70)
print("Loading Restaurant Review Advisor...")
print("="*70)

print("\n[1/3] Loading fine-tuned sentiment model...")

try:
    sentiment_analyzer = pipeline(
        "sentiment-analysis",
        model="Isap31/restaurant-sentiment-distilbert"
    )
    print("✅ Sentiment model loaded (94.93% accuracy)")
except Exception as e:
    print(f"Error loading sentiment model: {e}")
    sentiment_analyzer = None

print("\n[2/3] Setting up RAG knowledge base...")

try:
    # Load dataset
    dataset = load_dataset("fancyzhx/yelp_polarity", split="train")
    sampled_reviews = dataset.shuffle(seed=42).select(range(500))
    
    # Create ChromaDB
    chroma_client = chromadb.Client(Settings(
        anonymized_telemetry=False,
        allow_reset=True
    ))
    
    collection = chroma_client.create_collection(name="yelp_reviews")
    
    # Add reviews
    documents = []
    metadatas = []
    ids = []
    
    for idx, review in enumerate(sampled_reviews):
        if len(review['text']) >= 50:
            documents.append(review['text'])
            metadatas.append({'sentiment': 'positive' if review['label'] == 1 else 'negative'})
            ids.append(f"review_{idx}")
    
    collection.add(documents=documents, metadatas=metadatas, ids=ids)
    
    print(f"✅ RAG knowledge base ready with {len(documents)} reviews")
    
    # Load generation model
    generator = pipeline("text2text-generation", model="google/flan-t5-small", max_length=150)
    print("✅ RAG generation model loaded")
    
    rag_ready = True
except Exception as e:
    print(f"Error setting up RAG: {e}")
    rag_ready = False
    collection = None
    generator = None
    
print("\n[3/3] Setting up application...")

def analyze_sentiment(text):
    """Analyze sentiment of restaurant review"""
    if not text.strip():
        return "⚪ No input provided"
    
    if sentiment_analyzer is None:
        return "❌ Sentiment model not loaded"
    
    try:
        result = sentiment_analyzer(text)[0]
        label = result['label']
        confidence = result['score']
        
        if label.upper() in ['POSITIVE', 'LABEL_1', '1']:
            sentiment = f"🟢 POSITIVE ({confidence:.1%} confidence)"
            interpretation = "Great review! Customer is satisfied."
        else:
            sentiment = f"🔴 NEGATIVE ({confidence:.1%} confidence)"
            interpretation = "Negative feedback detected."
        
        return f"{sentiment}\n\n{interpretation}"
    except Exception as e:
        return f"❌ Error: {str(e)}"

def rag_query(question):
    """RAG system - retrieve reviews and generate answer"""
    if not question.strip():
        return "Please ask a question about restaurants."
    
    if not rag_ready:
        return "❌ RAG system not loaded"
    
    try:
        # Retrieval
        results = collection.query(query_texts=[question], n_results=3)
        
        if not results['documents'][0]:
            return "I couldn't find relevant reviews for that question."
        
        # Build context
        review_texts = []
        sentiments = []
        
        for doc, metadata in zip(results['documents'][0], results['metadatas'][0]):
            sentiment = metadata.get('sentiment', 'unknown')
            sentiments.append(sentiment)
            review_texts.append(f"[{sentiment.upper()}] {doc}")
        
        context = "\n\n".join(review_texts)
        
        # Generate
        prompt = f"""Based on these customer reviews, answer the question concisely.

Reviews:
{context}

Question: {question}

Answer:"""
        
        answer = generator(prompt, max_length=150)[0]['generated_text']
        
        # Format response
        response = f"**Generated Answer:**\n{answer}\n\n"
        response += f"**Based on:** {len(results['documents'][0])} customer reviews "
        response += f"({sentiments.count('positive')} positive, {sentiments.count('negative')} negative)"
        
        return response
        
    except Exception as e:
        return f"❌ Error: {str(e)}"

print("\nCreating Gradio interface...")

demo = gr.Interface(
    fn=analyze_sentiment,
    inputs=gr.Textbox(
        lines=3,
        placeholder="Enter restaurant review...",
        label="Review Text"
    ),
    outputs=gr.Textbox(label="Sentiment Analysis Result"),
    title="🍽️ Restaurant Review Advisor - Sentiment Analysis",
    description="""
    **Component 1: Fine-Tuned DistilBERT Sentiment Model (94.93% accuracy)**
    
    Trained on 50,000 Yelp restaurant reviews. Enter a review to analyze its sentiment!
    """,
    examples=[
        ["This restaurant exceeded all expectations! The service was impeccable and food was divine."],
        ["Worst dining experience ever. Cold food, rude staff, and overpriced."],
        ["The ambiance was nice, but the food was just okay."],
    ]
)

demo_rag = gr.Interface(
    fn=rag_query,
    inputs=gr.Textbox(
        lines=2,
        placeholder="Ask a question about restaurants...",
        label="Question"
    ),
    outputs=gr.Textbox(label="RAG Answer"),
    title="🔍 Restaurant Knowledge Query (RAG System)",
    description="""
    **Component 2: RAG with Yelp Reviews (Retrieval + Augmentation + Generation)**
    
    Ask questions and get answers based on 500+ real customer reviews!
    """,
    examples=[
        ["What do customers say about food quality at restaurants?"],
        ["Are portions typically good at restaurants?"],
        ["What about customer service?"],
    ]
)

app = gr.TabbedInterface(
    [demo, demo_rag],
    ["Sentiment Analysis", "RAG Knowledge Query"],
    title="☕ Restaurant Review Advisor - INFO 452 Final Project"
)

print("✅ Gradio interface ready!")
print("="*70)
print("Launching application...")

if __name__ == "__main__":
    app.launch()