import gradio as gr

def reply(user_msg: str, history: list, name: str):
    name = name or "friend"
    assistant_msg = f"Nice to meet you, {name}! You said: {user_msg}"
    
    history = history + [
        {"role": "user", "content": user_msg},
        {"role": "assistant", "content": assistant_msg},
    ]
    return history, "" # clear the textbox

def set_name_and_greet(name: str):
    name = name or "friend"
    greeting = [
        {"role": "assistant", "content": f"Hi, {name}! How can I help you?"}
    ]
    return name, greeting # matches the two outputs

with gr.Blocks() as demo:
    name_state = gr.State("") # remembers the chosen name

    with gr.Row():
        with gr.Column(scale=1):
            gr.Markdown("### Enter your name, then click **Set Name**")
            name_input = gr.Textbox(placeholder="Type your name here…")
            set_btn = gr.Button("Set Name")
            gr.Markdown("_After the greeting appears, start chatting →_")

        with gr.Column(scale=2):
            chatbot = gr.Chatbot(label="Chat", type="messages")
            user_text = gr.Textbox(placeholder="Ask me something…")

    set_btn.click(
        fn=set_name_and_greet,
        inputs=name_input,
        outputs=[name_state, chatbot], # update state & chatbot history
        show_progress=False,
    )

    user_text.submit(
        fn=reply,
        inputs=[user_text, chatbot, name_state], # latest msg, history, name
        outputs=[chatbot, user_text], # update history & clear input
    )

demo.launch()