app.py

import os
import time
import streamlit as st
from twilio.rest import Client
from pdfminer.high_level import extract_text
from sentence_transformers import SentenceTransformer
from transformers import AutoTokenizer
import faiss
import numpy as np
import docx
from groq import Groq
import PyPDF2
import requests

# --- Auto-refresh every 10 seconds ---
if "last_refresh" not in st.session_state:
    st.session_state.last_refresh = time.time()
elif time.time() - st.session_state.last_refresh > 10:
    st.session_state.last_refresh = time.time()
    st.experimental_rerun()

# --- Document Loaders ---
def extract_text_from_pdf(pdf_path):
    try:
        text = ""
        with open(pdf_path, 'rb') as file:
            pdf_reader = PyPDF2.PdfReader(file)
            for page_num in range(len(pdf_reader.pages)):
                page = pdf_reader.pages[page_num]
                page_text = page.extract_text()
                if page_text:
                    text += page_text
        return text
    except:
        return extract_text(pdf_path)

def extract_text_from_docx(docx_path):
    try:
        doc = docx.Document(docx_path)
        return '\n'.join(para.text for para in doc.paragraphs)
    except:
        return ""

def chunk_text(text, tokenizer, chunk_size=150, chunk_overlap=30):
    tokens = tokenizer.tokenize(text)
    chunks, start = [], 0
    while start < len(tokens):
        end = min(start + chunk_size, len(tokens))
        chunk_tokens = tokens[start:end]
        chunks.append(tokenizer.convert_tokens_to_string(chunk_tokens))
        start += chunk_size - chunk_overlap
    return chunks

def retrieve_chunks(question, index, embed_model, text_chunks, k=3):
    question_embedding = embed_model.encode([question])[0]
    D, I = index.search(np.array([question_embedding]), k)
    return [text_chunks[i] for i in I[0]]

# --- GROQ Answer Generation ---
def generate_answer_with_groq(question, context, retries=3, delay=2):
    url = "https://api.groq.com/openai/v1/chat/completions"
    api_key = os.environ["GROQ_API_KEY"]
    headers = {
        "Authorization": f"Bearer {api_key}",
        "Content-Type": "application/json",
    }
    prompt = (
        f"Customer asked: '{question}'\n\n"
        f"Here is the relevant product or policy info to help:\n{context}\n\n"
        f"Respond in a friendly and helpful tone as a toy shop support agent."
    )
    payload = {
        "model": "llama3-8b-8192",
        "messages": [
            {
                "role": "system",
                "content": (
                    "You are ToyBot, a friendly and helpful WhatsApp assistant for an online toy shop. "
                    "Your goal is to politely answer customer questions, help them choose the right toys, "
                    "provide order or delivery information, explain return policies, and guide them through purchases. "
                    "Always sound warm, helpful, and trustworthy like a professional customer support agent."
                )
            },
            {"role": "user", "content": prompt},
        ],
        "temperature": 0.5,
        "max_tokens": 300,
    }

    for attempt in range(retries):
        try:
            response = requests.post(url, headers=headers, json=payload)
            result = response.json()
            return result['choices'][0]['message']['content'].strip()
        except Exception as e:
            if "503" in str(e) and attempt < retries - 1:
                time.sleep(delay)
                continue
            else:
                return f"⚠️ Groq API Error: {str(e)}"

# --- Twilio Chat Handlers ---
def fetch_latest_conversation_sid(account_sid, auth_token):
    try:
        client = Client(account_sid, auth_token)
        conversations = client.conversations.v1.conversations.list(limit=1)
        if conversations:
            return conversations[0].sid
    except Exception as e:
        st.error(f"⚠️ Could not fetch conversation SID: {e}")
    return None

def fetch_latest_incoming_message(account_sid, auth_token, conversation_sid):
    client = Client(account_sid, auth_token)
    messages = client.conversations.v1.conversations(conversation_sid).messages.list(limit=10)
    for msg in reversed(messages):
        if msg.author.startswith("whatsapp:"):
            return msg.body, msg.author, msg.index
    return None, None, None

def send_twilio_message(account_sid, auth_token, conversation_sid, body):
    try:
        client = Client(account_sid, auth_token)
        # Get participants to find the bot's WhatsApp identity
        participants = client.conversations.v1.conversations(conversation_sid).participants.list()
        # Pick the first participant whose identity starts with 'whatsapp:'
        bot_identity = None
        for p in participants:
            if p.identity.startswith("whatsapp:"):
                bot_identity = p.identity
                break
        if not bot_identity:
            return "⚠️ Bot identity with whatsapp: prefix not found in participants."

        message = client.conversations.v1.conversations(conversation_sid).messages.create(
            author=bot_identity,
            body=body
        )
        return message.sid
    except Exception as e:
        return str(e)


# --- Streamlit UI ---
st.set_page_config(page_title="Quasa – A Smart WhatsApp Chatbot", layout="wide")

st.markdown("""
    <style>
        .big-font { font-size: 28px !important; font-weight: bold; }
        .small-font { font-size: 16px; color: #555; }
        .stButton > button {
            background-color: #0066CC; color: white;
            padding: 0.5em 1em; border-radius: 8px; font-size: 18px;
        }
        .stTextInput > div > input { font-size: 16px; }
    </style>
""", unsafe_allow_html=True)

st.markdown('<div class="big-font">📱 Quasa – A Smart WhatsApp Chatbot</div>', unsafe_allow_html=True)
st.markdown('<div class="small-font">Talk to your documents using WhatsApp. Powered by Groq, Twilio, and RAG.</div>', unsafe_allow_html=True)

# Load secrets or fallback
account_sid = st.secrets.get("TWILIO_SID")
auth_token = st.secrets.get("TWILIO_TOKEN")
GROQ_API_KEY = st.secrets.get("GROQ_API_KEY")

if not all([account_sid, auth_token, GROQ_API_KEY]):
    st.warning("⚠️ Some secrets are missing. Please provide them manually:")
    account_sid = st.text_input("Twilio SID", value=account_sid or "")
    auth_token = st.text_input("Twilio Auth Token", type="password", value=auth_token or "")
    GROQ_API_KEY = st.text_input("GROQ API Key", type="password", value=GROQ_API_KEY or "")

if all([account_sid, auth_token, GROQ_API_KEY]):
    os.environ["GROQ_API_KEY"] = GROQ_API_KEY

    conversation_sid = fetch_latest_conversation_sid(account_sid, auth_token)

    if conversation_sid:
        @st.cache_resource
        def setup_knowledge_base():
            folder_path = "docs"
            all_text = ""
            for file in os.listdir(folder_path):
                if file.endswith(".pdf"):
                    all_text += extract_text_from_pdf(os.path.join(folder_path, file)) + "\n"
                elif file.endswith((".docx", ".doc")):
                    all_text += extract_text_from_docx(os.path.join(folder_path, file)) + "\n"
            tokenizer = AutoTokenizer.from_pretrained('bert-base-uncased')
            chunks = chunk_text(all_text, tokenizer)
            model = SentenceTransformer('all-mpnet-base-v2')
            embeddings = model.encode(chunks)
            dim = embeddings[0].shape[0]
            index = faiss.IndexFlatL2(dim)
            index.add(np.array(embeddings))
            return index, model, chunks

        index, embedding_model, text_chunks = setup_knowledge_base()

        st.success(f"✅ Knowledge base ready. Monitoring WhatsApp messages for conversation: `{conversation_sid}`")

        if "last_processed_index" not in st.session_state:
            st.session_state.last_processed_index = -1

        with st.spinner("Checking for new WhatsApp messages..."):
            question, sender, msg_index = fetch_latest_incoming_message(account_sid, auth_token, conversation_sid)

            if question and msg_index != st.session_state.last_processed_index:
                st.session_state.last_processed_index = msg_index
                st.info(f"📥 New question from **{sender}**:\n\n> {question}")
                relevant_chunks = retrieve_chunks(question, index, embedding_model, text_chunks)
                context = "\n\n".join(relevant_chunks)
                answer = generate_answer_with_groq(question, context)
                send_twilio_message(account_sid, auth_token, conversation_sid, answer)
                st.success("📤 Answer sent back to user on WhatsApp!")
                st.markdown(f"### ✨ Answer:\n\n{answer}")
            else:
                st.warning("No new messages found.")
    else:
        st.warning("❗ No active conversation found.")
else:
    st.warning("❗ Please provide all required credentials.")