app.py

import os
import threading
import logging
import uuid
import shutil
import json
import tempfile
import glob
from flask import Flask, request as flask_request, make_response
import dash
from dash import dcc, html, Input, Output, State, callback_context
import dash_bootstrap_components as dbc
import openai
import base64
import datetime
from werkzeug.utils import secure_filename
import numpy as np

logging.basicConfig(level=logging.INFO, format="%(asctime)s %(levelname)s %(threadName)s %(message)s")
logger = logging.getLogger("AskTricare")

app_flask = Flask(__name__)
SESSION_DATA = {}
SESSION_LOCKS = {}
SESSION_DIR_BASE = os.path.join(tempfile.gettempdir(), "asktricare_sessions")
os.makedirs(SESSION_DIR_BASE, exist_ok=True)

openai.api_key = os.environ.get("OPENAI_API_KEY")

EMBEDDING_INDEX = {}
EMBEDDING_TEXTS = {}
EMBEDDING_MODEL = "text-embedding-ada-002"

def get_session_id():
    sid = flask_request.cookies.get("asktricare_session_id")
    if not sid:
        sid = str(uuid.uuid4())
    return sid

def get_session_dir(session_id):
    d = os.path.join(SESSION_DIR_BASE, session_id)
    os.makedirs(d, exist_ok=True)
    return d

def get_session_lock(session_id):
    if session_id not in SESSION_LOCKS:
        SESSION_LOCKS[session_id] = threading.Lock()
    return SESSION_LOCKS[session_id]

def get_session_state(session_id):
    if session_id not in SESSION_DATA:
        SESSION_DATA[session_id] = {
            "messages": [],
            "uploads": [],
            "created": datetime.datetime.utcnow().isoformat(),
            "streaming": False,
            "stream_buffer": "",
            "chat_histories": []
        }
    return SESSION_DATA[session_id]

def save_session_state(session_id):
    state = get_session_state(session_id)
    d = get_session_dir(session_id)
    with open(os.path.join(d, "state.json"), "w") as f:
        json.dump(state, f)

def load_session_state(session_id):
    d = get_session_dir(session_id)
    path = os.path.join(d, "state.json")
    if os.path.exists(path):
        with open(path, "r") as f:
            SESSION_DATA[session_id] = json.load(f)

def load_system_prompt():
    prompt_path = os.path.join(os.getcwd(), "system_prompt.txt")
    try:
        with open(prompt_path, "r", encoding="utf-8") as f:
            return f.read().strip()
    except Exception as e:
        logger.error(f"Failed to load system prompt: {e}")
        return "You are Ask Tricare, a helpful assistant for TRICARE health benefits. Respond conversationally, and cite relevant sources when possible. If you do not know, say so."

def embed_docs_folder():
    global EMBEDDING_INDEX, EMBEDDING_TEXTS
    docs_folder = os.path.join(os.getcwd(), "docs")
    if not os.path.isdir(docs_folder):
        logger.warning(f"Docs folder '{docs_folder}' does not exist. Skipping embedding.")
        return
    doc_files = []
    for ext in ("*.txt", "*.md", "*.pdf"):
        doc_files.extend(glob.glob(os.path.join(docs_folder, ext)))
    for doc_path in doc_files:
        fname = os.path.basename(doc_path)
        if fname in EMBEDDING_INDEX:
            continue
        try:
            with open(doc_path, "r", encoding="utf-8", errors="ignore") as f:
                text = f.read()
            if not text.strip():
                continue
            chunk = text[:4000]
            response = openai.Embedding.create(
                input=[chunk],
                model=EMBEDDING_MODEL
            )
            embedding = response['data'][0]['embedding']
            EMBEDDING_INDEX[fname] = embedding
            EMBEDDING_TEXTS[fname] = chunk
            logger.info(f"Embedded doc: {fname}")
        except Exception as e:
            logger.error(f"Embedding failed for {fname}: {e}")

embed_docs_folder()

def embed_user_doc(session_id, filename, text):
    session_dir = get_session_dir(session_id)
    if not text.strip():
        return
    try:
        chunk = text[:4000]
        response = openai.Embedding.create(
            input=[chunk],
            model=EMBEDDING_MODEL
        )
        embedding = response['data'][0]['embedding']
        user_embeds_path = os.path.join(session_dir, "user_embeds.json")
        if os.path.exists(user_embeds_path):
            with open(user_embeds_path, "r") as f:
                user_embeds = json.load(f)
        else:
            user_embeds = {"embeddings": [], "texts": [], "filenames": []}
        user_embeds["embeddings"].append(embedding)
        user_embeds["texts"].append(chunk)
        user_embeds["filenames"].append(filename)
        with open(user_embeds_path, "w") as f:
            json.dump(user_embeds, f)
        logger.info(f"Session {session_id}: Embedded user doc {filename}")
    except Exception as e:
        logger.error(f"Session {session_id}: Failed to embed user doc {filename}: {e}")

def get_user_embeddings(session_id):
    session_dir = get_session_dir(session_id)
    user_embeds_path = os.path.join(session_dir, "user_embeds.json")
    if os.path.exists(user_embeds_path):
        with open(user_embeds_path, "r") as f:
            d = json.load(f)
        embeds = np.array(d.get("embeddings", []))
        texts = d.get("texts", [])
        filenames = d.get("filenames", [])
        return embeds, texts, filenames
    return np.array([]), [], []

def semantic_search(query, embed_matrix, texts, filenames, top_k=2):
    if len(embed_matrix) == 0:
        return []
    try:
        q_embed = openai.Embedding.create(input=[query], model=EMBEDDING_MODEL)["data"][0]["embedding"]
        q_embed = np.array(q_embed)
        embed_matrix = np.array(embed_matrix)
        scores = np.dot(embed_matrix, q_embed) / (np.linalg.norm(embed_matrix, axis=1) * np.linalg.norm(q_embed) + 1e-8)
        idx = np.argsort(scores)[::-1][:top_k]
        results = []
        for i in idx:
            results.append({"filename": filenames[i], "text": texts[i], "score": float(scores[i])})
        return results
    except Exception as e:
        logger.error(f"Semantic search error: {e}")
        return []

app = dash.Dash(
    __name__,
    server=app_flask,
    suppress_callback_exceptions=True,
    external_stylesheets=[dbc.themes.BOOTSTRAP, "/assets/custom.css"],
    update_title="Ask Tricare"
)

def chat_message_card(msg, is_user):
    align = "end" if is_user else "start"
    color = "primary" if is_user else "secondary"
    avatar = "🧑" if is_user else "🤖"
    return dbc.Card(
        dbc.CardBody([
            html.Div([
                html.Span(avatar, style={"fontSize": "2rem"}),
                html.Span(msg, style={"whiteSpace": "pre-wrap", "marginLeft": "0.75rem"})
            ], style={"display": "flex", "alignItems": "center", "justifyContent": align})
        ]),
        className=f"mb-2 ms-3 me-3",
        color=color,
        inverse=is_user,
        style={"maxWidth": "80%", "alignSelf": f"flex-{align}"}
    )

def uploaded_file_card(filename, is_img):
    ext = os.path.splitext(filename)[1].lower()
    icon = "🖼️" if is_img else "📄"
    return dbc.Card(
        dbc.CardBody([
            html.Span(icon, style={"fontSize": "2rem", "marginRight": "0.5rem"}),
            html.Span(filename)
        ]),
        className="mb-2",
        color="tertiary"
    )

def disclaimer_card():
    return dbc.Card(
        dbc.CardBody([
            html.H5("Disclaimer", className="card-title"),
            html.P("This information is not private. Do not send PII or PHI. For official guidance visit the Tricare website.", style={"fontSize": "0.95rem"})
        ]),
        className="mb-2"
    )

def left_navbar_static():
    return html.Div([
        html.H3("Ask Tricare", className="mb-3 mt-3", style={"fontWeight": "bold"}),
        disclaimer_card(),
        dcc.Upload(
            id="file-upload",
            children=dbc.Button("Upload Document/Image", color="secondary", className="mb-2", style={"width": "100%"}),
            multiple=True,
            style={"width": "100%"}
        ),
        html.Div(id="upload-list"),
        html.Hr(),
        html.H5("Chat History", className="mb-2"),
        html.Ul(id="chat-history-list", style={"listStyle": "none", "paddingLeft": "0"}),
    ], style={"padding": "1rem", "backgroundColor": "#f8f9fa", "height": "100vh", "overflowY": "auto"})

def chat_box_card():
    return dbc.Card(
        dbc.CardBody([
            html.Div(id="chat-window", style={
                "height": "60vh",
                "overflowY": "auto",
                "display": "flex",
                "flexDirection": "column",
                "justifyContent": "flex-end",
                "backgroundColor": "#fff",
                "padding": "0.5rem",
                "borderRadius": "0.5rem"
            })
        ]),
        className="mt-3"
    )

def user_input_card():
    return dbc.Card(
        dbc.CardBody([
            html.Div([
                dcc.Textarea(
                    id="user-input",
                    placeholder="Type your question...",
                    style={"width": "100%", "height": "60px", "resize": "vertical", "wordWrap": "break-word"},
                    wrap="soft",
                    maxLength=1000,
                    n_submit=0,
                    n_blur=0,
                ),
                dcc.Store(id="enter-triggered", data=False),
                html.Div([
                    dbc.Button("Send", id="send-btn", color="primary", className="mt-2 me-2", style={"minWidth": "100px"}),
                    dbc.Button("New Chat", id="new-chat-btn", color="secondary", className="mt-2", style={"minWidth": "110px"}),
                ], style={"float": "right", "display": "flex", "gap": "0.5rem"}),
                dcc.Store(id="user-input-store", data="", storage_type="session"),
                html.Button(id='hidden-send', style={'display': 'none'})
            ], style={"marginTop": "1rem"}),
            html.Div(id="error-message", style={"color": "#bb2124", "marginTop": "0.5rem"}),
            dcc.Store(id="should-clear-input", data=False)
        ])
    )

def right_main_static():
    return html.Div([
        chat_box_card(),
        user_input_card(),
        dcc.Loading(id="loading", type="default", fullscreen=False, style={"position": "absolute", "top": "5%", "left": "50%"}),
        dcc.Interval(id="stream-interval", interval=400, n_intervals=0, disabled=True, max_intervals=1000),
        dcc.Store(id="client-question", data="")
    ], style={"padding": "1rem", "backgroundColor": "#fff", "height": "100vh", "overflowY": "auto"})

app.layout = html.Div([
    dcc.Store(id="session-id", storage_type="local"),
    dcc.Location(id="url"),
    dcc.Store(id="selected-history", data=None),
    html.Div([
        html.Div(left_navbar_static(), id='left-navbar', style={"width": "30vw", "height": "100vh", "position": "fixed", "left": 0, "top": 0, "zIndex": 2, "overflowY": "auto"}),
        html.Div(right_main_static(), id='right-main', style={"marginLeft": "30vw", "width": "70vw", "overflowY": "auto"})
    ], style={"display": "flex"}),
    dcc.Store(id="clear-input", data=False),
    dcc.Store(id="scroll-bottom", data=0),
    # clientside callback for textarea enter/shift-enter
    dcc.Store(id="enter-pressed", data=False)
])

# JS callback to intercept Enter/Shift+Enter for dcc.Textarea
app.clientside_callback(
    """
    function(n, value) {
        var ta = document.getElementById('user-input');
        if (!ta) return window.dash_clientside.no_update;
        if (!window._asktricare_enter_handler) {
            ta.addEventListener('keydown', function(e) {
                if (e.key === 'Enter' && !e.shiftKey) {
                    e.preventDefault();
                    var btn = document.getElementById('hidden-send');
                    if (btn) btn.click();
                }
            });
            window._asktricare_enter_handler = true;
        }
        return window.dash_clientside.no_update;
    }
    """,
    Output('enter-pressed', 'data'),
    Input('user-input', 'n_blur'),
    State('user-input', 'value')
)

def _is_supported_doc(filename):
    ext = os.path.splitext(filename)[1].lower()
    return ext in [".txt", ".pdf", ".md", ".docx"]

def _extract_text_from_upload(filepath, ext):
    # Only .txt and .md are extracted for now
    if ext in [".txt", ".md"]:
        try:
            with open(filepath, "r", encoding="utf-8", errors="ignore") as f:
                text = f.read()
            return text
        except Exception as e:
            logger.error(f"Error reading {filepath}: {e}")
            return ""
    else:
        return ""

@app.callback(
    Output("session-id", "data"),
    Input("url", "href"),
    prevent_initial_call=False
)
def assign_session_id(_):
    sid = get_session_id()
    d = get_session_dir(sid)
    load_session_state(sid)
    logger.info(f"Assigned session id: {sid}")
    return sid

@app.callback(
    Output("upload-list", "children"),
    Output("chat-history-list", "children"),
    Output("chat-window", "children"),
    Output("error-message", "children"),
    Output("stream-interval", "disabled"),
    Output("stream-interval", "n_intervals"),
    Output("user-input", "value"),
    Output("selected-history", "data"),
    Input("session-id", "data"),
    Input("send-btn", "n_clicks"),
    Input("file-upload", "contents"),
    Input("new-chat-btn", "n_clicks"),
    Input("stream-interval", "n_intervals"),
    Input({"type": "chat-history-item", "index": dash.ALL}, "n_clicks"),
    Input('hidden-send', 'n_clicks'),
    State("file-upload", "filename"),
    State("user-input", "value"),
    State("selected-history", "data"),
    State("chat-history-list", "children"),
    prevent_initial_call=False
)
def main_callback(session_id, send_clicks, file_contents, new_chat_clicks, stream_n, chat_history_clicks, hidden_send_clicks, file_names, user_input, selected_history, chat_history_list_children):
    trigger = callback_context.triggered[0]['prop_id'].split('.')[0] if callback_context.triggered else ""
    session_id = session_id or get_session_id()
    session_lock = get_session_lock(session_id)
    with session_lock:
        load_session_state(session_id)
        state = get_session_state(session_id)
        error = ""
        start_streaming = False
        chat_histories = state.get("chat_histories", [])
        uploads = state.get("uploads", [])

        # Handle clickable chat history loading
        history_index_clicked = None
        if trigger == "" and chat_history_clicks:
            for idx, n in enumerate(chat_history_clicks):
                if n:
                    history_index_clicked = idx
                    break
        elif trigger.startswith("{\"type\":\"chat-history-item\""):
            for idx, n in enumerate(chat_history_clicks):
                if n:
                    history_index_clicked = idx
                    break
        if history_index_clicked is not None and history_index_clicked < len(chat_histories):
            selected_dialog = chat_histories[history_index_clicked]["dialog"]
            state["messages"] = selected_dialog.copy()
            state["stream_buffer"] = ""
            state["streaming"] = False
            save_session_state(session_id)
            logger.info(f"Session {session_id}: Loaded chat history index {history_index_clicked}")
            # Rebuild downstream outputs with this dialog
            chat_cards = []
            for msg in state["messages"]:
                chat_cards.append(chat_message_card(msg['content'], is_user=(msg['role'] == "user")))
            upload_cards = [uploaded_file_card(os.path.basename(f["name"]), f["is_img"]) for f in state.get("uploads", [])]
            chat_history_items = [
                html.Li(
                    dbc.Button(
                        chat["name"],
                        id={"type": "chat-history-item", "index": i},
                        color="tertiary",
                        outline=False,
                        style={"width": "100%", "textAlign": "left", "fontWeight": "bold" if i == len(chat_histories)-1 else "normal", "fontSize": "0.92rem", "marginBottom": "0.2rem"}
                    )
                )
                for i, chat in enumerate(chat_histories[-6:])
            ]
            return (
                upload_cards,
                chat_history_items,
                chat_cards,
                "",
                True,
                0,
                "",
                history_index_clicked
            )

        # Handle File Upload
        file_was_uploaded_and_sent = False
        if trigger == "file-upload" and file_contents and file_names:
            uploads = []
            if not isinstance(file_contents, list):
                file_contents = [file_contents]
                file_names = [file_names]
            for c, n in zip(file_contents, file_names):
                header, data = c.split(',', 1)
                ext = os.path.splitext(n)[1].lower()
                is_img = ext in [".png", ".jpg", ".jpeg", ".gif", ".bmp", ".webp"]
                fname = secure_filename(f"{datetime.datetime.utcnow().strftime('%Y%m%d%H%M%S')}_{n}")
                session_dir = get_session_dir(session_id)
                fp = os.path.join(session_dir, fname)
                with open(fp, "wb") as f:
                    f.write(base64.b64decode(data))
                uploads.append({"name": fname, "is_img": is_img, "path": fp})
                if _is_supported_doc(n) and not is_img:
                    text = _extract_text_from_upload(fp, ext)
                    if text.strip():
                        embed_user_doc(session_id, fname, text)
                        logger.info(f"Session {session_id}: Uploaded doc '{n}' embedded for user vector store")
            state["uploads"].extend(uploads)
            save_session_state(session_id)
            logger.info(f"Session {session_id}: Uploaded files {[u['name'] for u in uploads]}")

        # Determine if send was triggered (via send-btn, hidden-send, or enter)
        send_triggered = False
        if trigger == "send-btn" or trigger == "hidden-send":
            send_triggered = True

        # Handle Send
        if send_triggered and user_input and user_input.strip():
            question = user_input.strip()
            state["messages"].append({"role": "user", "content": question})
            state["streaming"] = True
            state["stream_buffer"] = ""
            save_session_state(session_id)

            def run_stream(session_id, messages, question):
                try:
                    system_prompt = load_system_prompt()
                    # Retrieve relevant context from global RAG
                    rag_chunks = []
                    try:
                        # Search global docs
                        global_embeds = []
                        global_texts = []
                        global_fnames = []
                        for fname, emb in EMBEDDING_INDEX.items():
                            global_embeds.append(emb)
                            global_texts.append(EMBEDDING_TEXTS[fname])
                            global_fnames.append(fname)
                        global_rag = semantic_search(question, global_embeds, global_texts, global_fnames, top_k=2)
                        if global_rag:
                            for r in global_rag:
                                rag_chunks.append(f"Global doc [{r['filename']}]:\n{r['text'][:1000]}")
                        # Search user docs
                        user_embeds, user_texts, user_fnames = get_user_embeddings(session_id)
                        user_rag = semantic_search(question, user_embeds, user_texts, user_fnames, top_k=2)
                        if user_rag:
                            for r in user_rag:
                                rag_chunks.append(f"User upload [{r['filename']}]:\n{r['text'][:1000]}")
                    except Exception as e:
                        logger.error(f"Session {session_id}: RAG error: {e}")
                    context_block = ""
                    if rag_chunks:
                        context_block = "The following sources may help answer the question:\n\n" + "\n\n".join(rag_chunks) + "\n\n"
                    msg_list = [{"role": "system", "content": system_prompt}]
                    if context_block:
                        msg_list.append({"role": "system", "content": context_block})
                    for m in messages:
                        msg_list.append({"role": m["role"], "content": m["content"]})
                    response = openai.ChatCompletion.create(
                        model="gpt-3.5-turbo",
                        messages=msg_list,
                        max_tokens=700,
                        temperature=0.2,
                        stream=True,
                    )
                    reply = ""
                    for chunk in response:
                        delta = chunk["choices"][0]["delta"]
                        content = delta.get("content", "")
                        if content:
                            reply += content
                            session_lock = get_session_lock(session_id)
                            with session_lock:
                                load_session_state(session_id)
                                state = get_session_state(session_id)
                                state["stream_buffer"] = reply
                                save_session_state(session_id)
                    session_lock = get_session_lock(session_id)
                    with session_lock:
                        load_session_state(session_id)
                        state = get_session_state(session_id)
                        state["messages"].append({"role": "assistant", "content": reply})
                        state["stream_buffer"] = ""
                        state["streaming"] = False
                        save_session_state(session_id)
                    logger.info(f"Session {session_id}: User: {question} | Assistant: {reply}")
                except Exception as e:
                    session_lock = get_session_lock(session_id)
                    with session_lock:
                        load_session_state(session_id)
                        state = get_session_state(session_id)
                        state["streaming"] = False
                        state["stream_buffer"] = ""
                        save_session_state(session_id)
                    logger.error(f"Session {session_id}: Streaming error: {e}")

            threading.Thread(target=run_stream, args=(session_id, list(state["messages"]), question), daemon=True).start()
            start_streaming = True

        # Handle New Chat button logic: auto-name and reset
        if trigger == "new-chat-btn":
            chat_dialog = list(state.get("messages", []))
            if not chat_dialog:
                error = "No chat to save. Start chatting!"
            else:
                chat_title = "Chat " + datetime.datetime.utcnow().strftime("%Y-%m-%d %H:%M")
                state.setdefault("chat_histories", []).append({
                    "name": chat_title,
                    "dialog": chat_dialog
                })
                state["messages"] = []
                state["stream_buffer"] = ""
                state["streaming"] = False
                save_session_state(session_id)
                logger.info(f"Session {session_id}: Saved chat history '{chat_title}'")

        # Handle polling for streaming
        if trigger == "stream-interval":
            chat_history = state.get("messages", [])
            chat_cards = []
            for msg in chat_history:
                chat_cards.append(chat_message_card(msg['content'], is_user=(msg['role'] == "user")))
            if state.get("streaming", False):
                if state.get("stream_buffer", ""):
                    chat_cards.append(chat_message_card(state["stream_buffer"], is_user=False))
                upload_cards = [uploaded_file_card(os.path.basename(f["name"]), f["is_img"]) for f in state.get("uploads", [])]
                chat_history_items = [
                    html.Li(
                        dbc.Button(
                            chat["name"],
                            id={"type": "chat-history-item", "index": i},
                            color="tertiary",
                            outline=False,
                            style={"width": "100%", "textAlign": "left", "fontWeight": "bold" if i == len(state.get("chat_histories", []) )-1 else "normal", "fontSize": "0.92rem", "marginBottom": "0.2rem"}
                        )
                    )
                    for i, chat in enumerate(state.get("chat_histories", [])[-6:])
                ]
                return (
                    upload_cards,
                    chat_history_items,
                    chat_cards,
                    "",
                    False,
                    stream_n+1,
                    "",
                    selected_history
                )
            else:
                chat_cards = []
                for msg in state.get("messages", []):
                    chat_cards.append(chat_message_card(msg['content'], is_user=(msg['role'] == "user")))
                upload_cards = [uploaded_file_card(os.path.basename(f["name"]), f["is_img"]) for f in state.get("uploads", [])]
                chat_history_items = [
                    html.Li(
                        dbc.Button(
                            chat["name"],
                            id={"type": "chat-history-item", "index": i},
                            color="tertiary",
                            outline=False,
                            style={"width": "100%", "textAlign": "left", "fontWeight": "bold" if i == len(state.get("chat_histories", []))-1 else "normal", "fontSize": "0.92rem", "marginBottom": "0.2rem"}
                        )
                    )
                    for i, chat in enumerate(state.get("chat_histories", [])[-6:])
                ]
                return (
                    upload_cards,
                    chat_history_items,
                    chat_cards,
                    "",
                    True,
                    0,
                    "",
                    selected_history
                )

        # Default: Build Uploads, Chat History and Chat Window
        chat_history = state.get("messages", [])
        uploads = state.get("uploads", [])
        chat_histories = state.get("chat_histories", [])
        upload_cards = [uploaded_file_card(os.path.basename(f["name"]), f["is_img"]) for f in uploads]
        chat_history_items = [
            html.Li(
                dbc.Button(
                    chat["name"],
                    id={"type": "chat-history-item", "index": i},
                    color="tertiary",
                    outline=False,
                    style={"width": "100%", "textAlign": "left", "fontWeight": "bold" if i == len(chat_histories)-1 else "normal", "fontSize": "0.92rem", "marginBottom": "0.2rem"}
                )
            )
            for i, chat in enumerate(chat_histories[-6:])
        ]
        chat_cards = []
        for msg in chat_history:
            chat_cards.append(chat_message_card(msg['content'], is_user=(msg['role'] == "user")))
        if state.get("streaming", False):
            if state.get("stream_buffer", ""):
                chat_cards.append(chat_message_card(state["stream_buffer"], is_user=False))
            return upload_cards, chat_history_items, chat_cards, error, False, 0, "", selected_history
        # Always clear input after send
        if send_triggered:
            return upload_cards, chat_history_items, chat_cards, error, (not state.get("streaming", False)), 0, "", selected_history
        return upload_cards, chat_history_items, chat_cards, error, (not state.get("streaming", False)), 0, user_input or "", selected_history

@app_flask.after_request
def set_session_cookie(resp):
    sid = flask_request.cookies.get("asktricare_session_id")
    if not sid:
        sid = str(uuid.uuid4())
        resp.set_cookie("asktricare_session_id", sid, max_age=60*60*24*7, path="/")
    return resp

def cleanup_sessions(max_age_hours=48):
    now = datetime.datetime.utcnow()
    for sid in os.listdir(SESSION_DIR_BASE):
        d = os.path.join(SESSION_DIR_BASE, sid)
        try:
            state_path = os.path.join(d, "state.json")
            if os.path.exists(state_path):
                with open(state_path, "r") as f:
                    st = json.load(f)
                created = st.get("created")
                if created and (now - datetime.datetime.fromisoformat(created)).total_seconds() > max_age_hours * 3600:
                    shutil.rmtree(d)
                    logger.info(f"Cleaned up session {sid}")
        except Exception as e:
            logger.error(f"Cleanup error for {sid}: {e}")

try:
    import torch
    if torch.cuda.is_available():
        torch.set_default_tensor_type(torch.cuda.FloatTensor)
        logger.info("CUDA GPU detected and configured.")
except Exception as e:
    logger.warning(f"CUDA config failed: {e}")

if __name__ == '__main__':
    print("Starting the Dash application...")
    app.run(debug=True, host='0.0.0.0', port=7860, threaded=True)
    print("Dash application has finished running.")