app.py

import os
import zipfile
import chromadb
import gradio as gr
from langchain_core.prompts import ChatPromptTemplate
from langchain_core.runnables import RunnableLambda, RunnablePassthrough
from langchain_core.output_parsers import StrOutputParser
from langchain_together import ChatTogether
from langchain_community.vectorstores import Chroma
from langchain_community.embeddings import HuggingFaceEmbeddings

# Log: Check if chroma_store exists
if not os.path.exists("chroma_store"):
    print("🔍 chroma_store folder not found. Attempting to unzip...")
    try:
        with zipfile.ZipFile("chroma_store.zip", "r") as zip_ref:
            zip_ref.extractall("chroma_store")
        print("✅ Successfully extracted chroma_store.zip.")
    except Exception as e:
        print(f"❌ Failed to unzip chroma_store.zip: {e}")
else:
    print("✅ chroma_store folder already exists. Skipping unzip.")

# Initialize ChromaDB client
chroma_client = chromadb.PersistentClient(path="./chroma_store")

# Vector store and retriever
embedding_function = HuggingFaceEmbeddings(model_name="BAAI/bge-base-en-v1.5")
vectorstore = Chroma(
    client=chroma_client,
    collection_name="imageonline_chunks",
    embedding_function=embedding_function
)

retriever = vectorstore.as_retriever(search_kwargs={"k": 3, "filter": {"site": "imageonline"}})

# Retrieval logic
def retrieve_with_metadata(query, k=5):
    docs = retriever.get_relevant_documents(query)
    if not docs:
        return {"context": "No relevant context found.", "references": []}
    top_doc = docs[0]
    return {
        "context": top_doc.page_content,
        "references": [{
            "section": top_doc.metadata.get("section", "Unknown"),
            "source": top_doc.metadata.get("source", "Unknown")
        }]
    }

# LLM setup
llm = ChatTogether(
    model="meta-llama/Llama-3-8b-chat-hf",
    temperature=0.3,
    max_tokens=1024,
    top_p=0.7,
    together_api_key="a36246d65d8290f43667350b364c5b6bb8562eb50a4b947eec5bd7e79f2dffc6"
)

# Prompt template
prompt = ChatPromptTemplate.from_template("""
You are an expert assistant for ImageOnline Web Solutions.

Answer the user's query based ONLY on the following context:

{context}

Query: {question}
""")

rag_chain = (
    {
        "context": lambda x: retrieve_with_metadata(x)["context"],
        "question": RunnablePassthrough()
    }
    | prompt
    | llm
    | StrOutputParser()
)

def get_references(query):
    return retrieve_with_metadata(query)["references"]

# Gradio UI
def chat_interface(message, history):
    history = history or []
    history.append(("🧑 You: " + message, "⏳ Generating response..."))
    try:
        answer = rag_chain.invoke(message)
        references = get_references(message)
        if references:
            ref = references[0]
            ref_string = f"\n\n📚 **Reference:**\nSection: {ref['section']}\nURL: {ref['source']}"
        else:
            ref_string = "\n\n📚 **Reference:**\n_None available_"
        full_response = answer + ref_string
        history[-1] = ("🧑 You: " + message, "🤖 Bot: " + full_response)
    except Exception as e:
        history[-1] = ("🧑 You: " + message, f"🤖 Bot: ⚠️ {str(e)}")
    return history, history

def launch_gradio():
    with gr.Blocks() as demo:
        gr.Markdown("# 💬 ImageOnline RAG Chatbot")
        gr.Markdown("Ask about Website Designing, App Development, SEO, Hosting, etc.")
        chatbot = gr.Chatbot()
        state = gr.State([])
        with gr.Row():
            msg = gr.Textbox(placeholder="Ask your question here...", show_label=False, scale=8)
            send_btn = gr.Button("📨 Send", scale=1)
        msg.submit(chat_interface, inputs=[msg, state], outputs=[chatbot, state])
        send_btn.click(chat_interface, inputs=[msg, state], outputs=[chatbot, state])
        with gr.Row():
            clear_btn = gr.Button("🧹 Clear Chat")
            clear_btn.click(fn=lambda: ([], []), outputs=[chatbot, state])
    return demo

demo = launch_gradio()
demo.launch()