app.py

import os
import sys
import logging
import uuid
from typing import List, Dict, Any, Tuple
from logging.handlers import RotatingFileHandler

import gradio as gr
from tenacity import retry, stop_after_attempt, wait_exponential

from core.rag_engine import RAGEngine
from core.user_profile import UserProfile
from config.config import settings

# ======================================================================================
# Logging Setup
# ======================================================================================

os.makedirs("logs", exist_ok=True)

logging.basicConfig(
    level=getattr(logging, settings.LOG_LEVEL.upper(), logging.INFO),
    format=settings.LOG_FORMAT,
    handlers=[
        logging.StreamHandler(sys.stdout),
        RotatingFileHandler(
            settings.LOG_FILE_PATH,
            maxBytes=settings.LOG_FILE_MAX_BYTES,
            backupCount=settings.LOG_FILE_BACKUP_COUNT
        ),
    ],
)
logger = logging.getLogger(__name__)

# ======================================================================================
# Core Module Initialization
# ======================================================================================

@retry(stop=stop_after_attempt(3), wait=wait_exponential(multiplier=1, min=4, max=10))
def initialize_with_retry(func):
    """Initializes a component with retry logic."""
    try:
        return func()
    except Exception as e:
        logger.error(f"Initialization failed: {e}", exc_info=True)
        raise

try:
    user_profile = initialize_with_retry(UserProfile)
    rag_engine = initialize_with_retry(lambda: RAGEngine(user_profile=user_profile))
    logger.info("Core modules initialized successfully.")
except Exception as e:
    logger.critical(f"Fatal: Could not initialize core modules: {e}. Exiting.", exc_info=True)
    sys.exit(1)

# ======================================================================================
# Business Logic
# ======================================================================================

async def handle_chat_interaction(
    message: str, chat_history: List[List[str]], user_id: str, categories: List[str]
) -> List[List[str]]:
    """Handles the user's chat message, processes it, and updates the history."""
    if not message.strip():
        gr.Warning("Message cannot be empty. Please type a question.")
        return chat_history

    try:
        profile = user_profile.get_profile(user_id)
        profile["preferences"]["favorite_categories"] = categories
        user_profile.update_profile(user_id, profile)
        logger.info(f"Updated preferences for user {user_id}: {categories}")

        result = await rag_engine.process_query(query=message, user_id=user_id)
        response = result.get("answer", "Sorry, I could not find an answer.")

        sources = result.get("sources")
        if sources:
            response += "\n\n**Sources:**\n" + format_sources(sources)

        chat_history.append((message, response))
        logger.info(f"User {user_id} received response.")
        return chat_history

    except Exception as e:
        error_message = f"An unexpected error occurred: {str(e)}"
        logger.error(f"Error for user {user_id}: {error_message}", exc_info=True)
        gr.Warning("Sorry, I encountered a problem. Please try again or rephrase your question.")
        return chat_history

def format_sources(sources: List[Dict[str, Any]]) -> str:
    """Formats the source documents into a readable string."""
    if not sources:
        return ""
    formatted_list = [f"- **{source.get('title', 'Unknown Source')}** (Category: {source.get('category', 'N/A')})" for source in sources]
    return "\n".join(formatted_list)

# ======================================================================================
# Gradio UI Definition
# ======================================================================================

def handle_slider_change(value: int) -> None:
    """
    Handles the change event for the document loader slider.
    Note: This currently only shows a notification. A restart is required.
    """
    gr.Info(f"Document limit set to {int(value)}. Please restart the app for changes to take effect.")


def create_interface() -> gr.Blocks:
    """Creates and configures the Gradio web interface."""
    
    with gr.Blocks(
        title="TravelMate - Your AI Travel Assistant",
        theme=gr.themes.Base(),
    ) as demo:
        
        user_id = gr.State(lambda: str(uuid.uuid4()))

        gr.Markdown("""
        <div style="text-align: center;">
            <h1 style="font-size: 2.5em;">✈️ TravelMate</h1>
            <p style="font-size: 1.1em; color: #333;">Your AI-powered travel assistant. Ask me anything to plan your next trip!</p>
        </div>
        """)

        with gr.Accordion("Advanced Settings", open=False):
            doc_load_slider = gr.Slider(
                minimum=100,
                maximum=5000,
                value=settings.MAX_DOCUMENTS_TO_LOAD,
                step=100,
                label="Documents to Load",
                info="Controls how many documents are loaded for the RAG engine. Higher values may increase startup time.",
            )
            doc_load_slider.change(
                fn=handle_slider_change, inputs=[doc_load_slider], outputs=None
            )

        with gr.Row():
            with gr.Column(scale=2):
                chatbot = gr.Chatbot(
                    elem_id="chatbot",
                    label="TravelMate Chat",
                    height=600,
                    show_label=False,
                    show_copy_button=True,
                    bubble_full_width=False,
                    avatar_images=("assets/user_avatar.png", "assets/bot_avatar.png"),
                )
                with gr.Row():
                    msg = gr.Textbox(
                        placeholder="Ask me about destinations, flights, hotels...",
                        show_label=False,
                        container=False,
                        scale=8,
                    )
                    submit_btn = gr.Button("Send", variant="primary", scale=1)

            with gr.Column(scale=1):
                gr.Markdown("### Select Your Interests")
                categories = gr.CheckboxGroup(
                    choices=[
                        "Flights", "Hotels", "Destinations", "Activities", 
                        "Transportation", "Food & Dining", "Shopping", 
                        "Health & Safety", "Budget Planning"
                    ],
                    value=["Flights", "Hotels"],
                    label="Travel Categories",
                )
                gr.Markdown("### Example Questions")
                gr.Examples(
                    examples=[
                        "What are the best places to visit in Japan?",
                        "How do I find cheap flights to Europe?",
                        "What should I pack for a beach vacation?",
                        "Tell me about local customs in Thailand",
                        "What's the best time to visit Paris?",
                    ],
                    inputs=msg,
                )

        async def on_submit(message: str, history: List[List[str]], uid: str, cats: List[str]) -> Tuple[str, List[List[str]]]:
            """Handles submission and returns updated values for the message box and chatbot."""
            updated_history = await handle_chat_interaction(message, history, uid, cats)
            return "", updated_history

        submit_btn.click(on_submit, [msg, chatbot, user_id, categories], [msg, chatbot])
        msg.submit(on_submit, [msg, chatbot, user_id, categories], [msg, chatbot])

    return demo

# ======================================================================================
# Application Launch
# ======================================================================================

if __name__ == "__main__":
    try:
        app = create_interface()
        app.queue(default_concurrency_limit=settings.GRADIO_CONCURRENCY_COUNT)
        app.launch(
            server_name=settings.GRADIO_SERVER_NAME,
            server_port=settings.GRADIO_SERVER_PORT,
            share=settings.GRADIO_SHARE,
            show_error=True,
            show_api=False,
        )
    except Exception as e:
        logger.critical(f"Failed to launch Gradio app: {e}", exc_info=True)
        raise