app.py

import gradio as gr
from huggingface_hub import InferenceClient
import os
from src.data_processor import LegalDocProcessor
from src.hybrid_retriever import HybridRetriever

# --- Configuration & Initialization ---
INDEX_DIR = "index_storage"
PARENT_DATA = "data/parent_docs.json"
CHILD_DATA = "data/child_docs.json"

def initialize_retriever():
    try:
        if os.path.exists(INDEX_DIR):
            print("[*] Loading existing index...")
            return HybridRetriever(index_dir=INDEX_DIR)
        else:
            print("[*] Building new index...")
            processor = LegalDocProcessor(PARENT_DATA, CHILD_DATA)
            docs = processor.load_and_clean()
            if not docs:
                return None
            ret = HybridRetriever(documents=docs, index_dir=INDEX_DIR)
            ret.save_index()
            return ret
    except Exception as e:
        print(f"Error initializing retriever: {e}")
        return None

# Global retriever instance
retriever = initialize_retriever()

def respond(
    message,
    history, 
    system_message,
    max_tokens,
    temperature,
    top_p,
    hf_token: gr.OAuthToken | None = None,
):
    # 1. RETRIEVAL STEP
    context = ""
    if retriever:
        try:
            search_results = retriever.hybrid_search(message, top_k=3)
            context = "\n\nRELEVANT NEPALESE LAW CONTEXT:\n"
            if not search_results:
                context += "No specific legal clauses found for this query."
            for res in search_results:
                src = res.get('legal_document_source', 'Unknown')
                cid = res.get('parent_clause_id', 'N/A')
                txt = res.get('parent_clause_text', 'Text not found')
                context += f"--- Source: {src} ---\nClause: {cid}\nText: {txt}\n\n"
        except Exception as e:
            print(f"Retrieval Error: {e}")
            context = "\n(Error retrieving specific law context.)"

    # 2. PROMPT ENGINEERING
    augmented_system_message = (
        f"{system_message}\n\n"
        "You are a legal assistant specializing in Nepalese Law. "
        "Use the legal context provided below to answer. Cite the Source and Clause ID.\n"
        f"{context}"
    )

    # 3. TOKEN SETUP
    raw_token = hf_token.token if (hf_token and hasattr(hf_token, 'token')) else os.getenv("HF_TOKEN", "")
    token = raw_token.strip() if raw_token else None
    if not token:
        yield "⚠️ Error: Please sign in with Hugging Face (see sidebar) or set HF_TOKEN secret."
        return

    client = InferenceClient(token=token, model="meta-llama/Llama-3.1-70B-Instruct")

    # 4. UNIVERSAL HISTORY PARSER (Handles both List of Lists and List of Dicts)
    messages = [{"role": "system", "content": augmented_system_message}]
    
    for item in history:
        if isinstance(item, dict):
            # Gradio 5 or Newer Gradio 4 format: {"role": "user", "content": "..."}
            messages.append({"role": item["role"], "content": item["content"]})
        elif isinstance(item, (list, tuple)):
            # Traditional Gradio 4 format: [user_msg, bot_msg]
            u, a = item
            if u: messages.append({"role": "user", "content": u})
            if a: messages.append({"role": "assistant", "content": a})
        
    messages.append({"role": "user", "content": message})

    # 5. GENERATION
    response = ""
    try:
        for msg in client.chat_completion(
            messages,
            max_tokens=max_tokens,
            stream=True,
            temperature=temperature,
            top_p=top_p,
        ):
            token_text = msg.choices[0].delta.content
            if token_text:
                response += token_text
                yield response
    except Exception as e:
        yield f"AI Error: {str(e)}"

# --- Gradio UI Setup ---
chatbot = gr.ChatInterface(
    respond,
    # REMOVED type="messages" to fix TypeError
    additional_inputs=[
        gr.Textbox(value="You are a helpful Nepalese Legal Advisor.", label="System message"),
        gr.Slider(minimum=1, maximum=2048, value=1024, step=1, label="Max tokens"),
        gr.Slider(minimum=0.1, maximum=4.0, value=0.7, step=0.1, label="Temperature"),
        gr.Slider(minimum=0.1, maximum=1.0, value=0.95, step=0.05, label="Top-p"),
    ],
    title="Nepal Law Search AI",
    description="Ask questions about Nepalese Constitution and Acts.",
    examples=[
        ["What are the punishments for cybercrime?"],
        ["What does the constitution say about the right to equality?"],
        ["Is witchcraft accusation a crime in Nepal?"]
    ],
    cache_examples=False,
)

with gr.Blocks() as demo:
    with gr.Sidebar():
        gr.Markdown("### Authentication")
        gr.LoginButton()
        gr.Markdown("---")
        gr.Markdown("**Status:** Database Ready ✅")
    chatbot.render()

if __name__ == "__main__":
    # Disable SSR to avoid Python 3.13 asyncio noise
    demo.launch(ssr_mode=False, show_error=True)