app.py

import datetime

from openai import OpenAI
import gradio as gr

from theme import apriel
from utils import COMMUNITY_POSTFIX_URL, get_model_config, log_message, check_format, models_config, DEBUG_MODE

MODEL_TEMPERATURE = 0.8
BUTTON_WIDTH = 160

DEFAULT_MODEL_NAME = "Apriel-Nemotron-15b-Thinker" if not DEBUG_MODE else "Apriel-5b"
# DEFAULT_MODEL_NAME = "Apriel-5b"

print(f"Gradio version: {gr.__version__}")

BUTTON_ENABLED = gr.update(interactive=True)
BUTTON_DISABLED = gr.update(interactive=False)
INPUT_ENABLED = gr.update(interactive=True)
INPUT_DISABLED = gr.update(interactive=False)
DROPDOWN_ENABLED = gr.update(interactive=True)
DROPDOWN_DISABLED = gr.update(interactive=False)

SEND_BUTTON_ENABLED = gr.update(interactive=True, visible=True)
SEND_BUTTON_DISABLED = gr.update(interactive=True, visible=False)
STOP_BUTTON_ENABLED = gr.update(interactive=True, visible=True)
STOP_BUTTON_DISABLED = gr.update(interactive=True, visible=False)

chat_start_count = 0
model_config = {}
openai_client = None


def update_model_and_clear_chat(model_name):
    actual_model_name = model_name.replace("Model: ", "")
    desc = setup_model(actual_model_name)
    return desc, []


def setup_model(model_name, intial=False):
    global model_config, openai_client
    model_config = get_model_config(model_name)
    log_message(f"update_model() --> Model config: {model_config}")
    openai_client = OpenAI(
        api_key=model_config.get('AUTH_TOKEN'),
        base_url=model_config.get('VLLM_API_URL')
    )

    _model_hf_name = model_config.get("MODEL_HF_URL").split('https://huggingface.co/')[1]
    _link = f"<a href='{model_config.get('MODEL_HF_URL')}{COMMUNITY_POSTFIX_URL}' target='_blank'>{_model_hf_name}</a>"
    _description = f"We'd love to hear your thoughts on the model. Click here to provide feedback - {_link}"

    print(f"Switched to model {_model_hf_name}")

    if intial:
        return
    else:
        return _description


def chat_started():
    # outputs: model_dropdown, user_input, send_btn, stop_btn, clear_btn
    return (DROPDOWN_DISABLED, gr.update(value="", interactive=False),
            SEND_BUTTON_DISABLED, STOP_BUTTON_ENABLED, BUTTON_DISABLED)


def chat_finished():
    # outputs: model_dropdown, user_input, send_btn, stop_btn, clear_btn
    return DROPDOWN_ENABLED, INPUT_ENABLED, SEND_BUTTON_ENABLED, STOP_BUTTON_DISABLED, BUTTON_ENABLED


def stop_chat(state):
    state["stop_flag"] = True
    gr.Info("Chat stopped")
    return state


def run_chat_inference(history, message, state):
    global chat_start_count
    state["is_streaming"] = True
    state["stop_flag"] = False

    # outputs: model_dropdown, user_input, send_btn, stop_btn, clear_btn, session_state
    log_message(f"{'-' * 80}")
    log_message(f"chat_fn() --> Message: {message}")
    log_message(f"chat_fn() --> History: {history}")

    try:
        # Check if the message is empty
        if not message.strip():
            gr.Info("Please enter a message before sending")
            yield history, INPUT_ENABLED, SEND_BUTTON_ENABLED, STOP_BUTTON_DISABLED, BUTTON_ENABLED, state
            return history, INPUT_ENABLED, SEND_BUTTON_ENABLED, STOP_BUTTON_DISABLED, BUTTON_ENABLED, state

        chat_start_count = chat_start_count + 1
        print(
            f"{datetime.datetime.now()}: chat_start_count: {chat_start_count}, turns: {int(len(history if history else []) / 3)}")

        is_reasoning = model_config.get("REASONING")

        # Remove any assistant messages with metadata from history for multiple turns
        log_message(f"Initial History: {history}")
        check_format(history, "messages")
        history.append({"role": "user", "content": message})
        log_message(f"History with user message: {history}")
        check_format(history, "messages")

        # Create the streaming response
        try:
            history_no_thoughts = [item for item in history if
                                   not (isinstance(item, dict) and
                                        item.get("role") == "assistant" and
                                        isinstance(item.get("metadata"), dict) and
                                        item.get("metadata", {}).get("title") is not None)]
            log_message(f"Updated History: {history_no_thoughts}")
            check_format(history_no_thoughts, "messages")
            log_message(f"history_no_thoughts with user message: {history_no_thoughts}")

            stream = openai_client.chat.completions.create(
                model=model_config.get('MODEL_NAME'),
                messages=history_no_thoughts,
                temperature=MODEL_TEMPERATURE,
                stream=True
            )
        except Exception as e:
            print(f"Error: {e}")
            yield ([{"role": "assistant",
                     "content": "😔 The model is unavailable at the moment. Please try again later."}],
                   INPUT_ENABLED, SEND_BUTTON_ENABLED, STOP_BUTTON_DISABLED, BUTTON_ENABLED, state)
            return history, INPUT_ENABLED, SEND_BUTTON_ENABLED, STOP_BUTTON_DISABLED, BUTTON_ENABLED, state

        if is_reasoning:
            history.append(gr.ChatMessage(
                role="assistant",
                content="Thinking...",
                metadata={"title": "🧠 Thought"}
            ))
            log_message(f"History added thinking: {history}")
            check_format(history, "messages")
        else:
            history.append(gr.ChatMessage(
                role="assistant",
                content="",
            ))
            log_message(f"History added empty assistant: {history}")
            check_format(history, "messages")

        output = ""
        completion_started = False
        for chunk in stream:
            if state["stop_flag"]:
                log_message(f"chat_fn() --> Stopping streaming...")
                break  # Exit the loop if the stop flag is set
            # Extract the new content from the delta field
            content = getattr(chunk.choices[0].delta, "content", "")
            output += content

            if is_reasoning:
                parts = output.split("[BEGIN FINAL RESPONSE]")

                if len(parts) > 1:
                    if parts[1].endswith("[END FINAL RESPONSE]"):
                        parts[1] = parts[1].replace("[END FINAL RESPONSE]", "")
                    if parts[1].endswith("[END FINAL RESPONSE]\n<|end|>"):
                        parts[1] = parts[1].replace("[END FINAL RESPONSE]\n<|end|>", "")
                    if parts[1].endswith("<|end|>"):
                        parts[1] = parts[1].replace("<|end|>", "")

                history[-1 if not completion_started else -2] = gr.ChatMessage(
                    role="assistant",
                    content=parts[0],
                    metadata={"title": "🧠 Thought"}
                )
                if completion_started:
                    history[-1] = gr.ChatMessage(
                        role="assistant",
                        content=parts[1]
                    )
                elif len(parts) > 1 and not completion_started:
                    completion_started = True
                    history.append(gr.ChatMessage(
                        role="assistant",
                        content=parts[1]
                    ))
            else:
                if output.endswith("<|end|>"):
                    output = output.replace("<|end|>", "")
                history[-1] = gr.ChatMessage(
                    role="assistant",
                    content=output
                )

            # log_message(f"Yielding messages: {history}")
            yield history, INPUT_DISABLED, SEND_BUTTON_DISABLED, STOP_BUTTON_ENABLED, BUTTON_DISABLED, state

        log_message(f"Final History: {history}")
        check_format(history, "messages")
        yield history, INPUT_ENABLED, SEND_BUTTON_ENABLED, STOP_BUTTON_DISABLED, BUTTON_ENABLED, state
    finally:
        state["is_streaming"] = False
        state["stop_flag"] = False
        log_message(f"chat_fn() --> Finished streaming. {chat_start_count} chats started.")
        return history, INPUT_ENABLED, SEND_BUTTON_ENABLED, STOP_BUTTON_DISABLED, BUTTON_ENABLED, state


title = None
description = None
theme = apriel

with open('styles.css', 'r') as f:
    custom_css = f.read()

with gr.Blocks(theme=theme, css=custom_css) as demo:
    session_state = gr.State(value={"is_streaming": False, "stop_flag": False})  # Store session state as a dictionary

    gr.HTML(f"""
        <style>
            @media (min-width: 1024px) {{
                .send-button-container, .clear-button-container {{
                    max-width: {BUTTON_WIDTH}px;
                }}
            }}
        </style>
        """, elem_classes="css-styles")
    with gr.Row(variant="panel", elem_classes="responsive-row"):
        with gr.Column(scale=1, min_width=400, elem_classes="model-dropdown-container"):
            model_dropdown = gr.Dropdown(
                choices=[f"Model: {model}" for model in models_config.keys()],
                value=f"Model: {DEFAULT_MODEL_NAME}",
                label=None,
                interactive=True,
                container=False,
                scale=0,
                min_width=400
            )
        with gr.Column(scale=4, min_width=0):
            description_html = gr.HTML(description, elem_classes="model-message")

    chatbot = gr.Chatbot(
        type="messages",
        height="calc(100dvh - 280px)",
        elem_classes="chatbot",
    )

    with gr.Row():
        with gr.Column(scale=10, min_width=400, elem_classes="user-input-container"):
            user_input = gr.Textbox(
                show_label=False,
                placeholder="Type your message here and press Enter",
                container=False
            )
        with gr.Column(scale=1, min_width=BUTTON_WIDTH * 2 + 20):
            with gr.Row():
                with gr.Column(scale=1, min_width=BUTTON_WIDTH, elem_classes="send-button-container"):
                    send_btn = gr.Button("Send", variant="primary")
                    stop_btn = gr.Button("Stop", variant="cancel", visible=False)
                with gr.Column(scale=1, min_width=BUTTON_WIDTH, elem_classes="clear-button-container"):
                    clear_btn = gr.ClearButton(chatbot, value="New Chat", variant="secondary")

    gr.on(
        triggers=[send_btn.click, user_input.submit],
        fn=run_chat_inference,  # this generator streams results. do not use logged_event_handler wrapper
        inputs=[chatbot, user_input, session_state],
        outputs=[chatbot, user_input, send_btn, stop_btn, clear_btn, session_state]
    ).then(
        fn=chat_finished, inputs=None, outputs=[model_dropdown, user_input, send_btn, stop_btn, clear_btn], queue=False)

    # In parallel, disable or update the UI controls
    gr.on(
        triggers=[send_btn.click, user_input.submit],
        fn=chat_started,
        inputs=None,
        outputs=[model_dropdown, user_input, send_btn, stop_btn, clear_btn],
        queue=False,
        show_progress='hidden'
    )

    stop_btn.click(
        fn=stop_chat,
        inputs=[session_state],
        outputs=[session_state]
    )

    # Ensure the model is reset to default on page reload
    demo.load(lambda: setup_model(DEFAULT_MODEL_NAME, intial=False), [], [description_html])

    model_dropdown.change(
        fn=update_model_and_clear_chat,
        inputs=[model_dropdown],
        outputs=[description_html, chatbot]
    )

demo.launch(ssr_mode=False, show_api=False)