import gradio as gr

def process_question(question, history, uploaded_files):
    # This is where you would integrate your RAG system logic.
    # For this example, we'll just return a placeholder response.
    if uploaded_files is None:
        return history, [("", "Please upload a PDF first.")]
    answer = f"Answer to: {question} (Based on {len(uploaded_files)} uploaded files)"
    history.append((question, answer))
    return history, [("", answer)]

with gr.Blocks(css="""
    body {
        background-color: #f4f4f4;
    }
    .gradio-container {
        border-radius: 10px;
        box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
    }
    .container {
        padding: 20px;
    }
    .question-area {
        margin-bottom: 20px;
    }
    .history-button {
        background-color: #4CAF50;
        color: white;
        padding: 10px 20px;
        border: none;
        border-radius: 5px;
        cursor: pointer;
    }
    .history-button:hover {
        background-color: #46a049;
    }
    .gradio-chatbot > .wrap > div:last-child > div:last-child {
        display: none !important;
    }
""") as demo:
    gr.Markdown("## RAG System Demo")

    with gr.Tabs() as tabs:
        with gr.TabItem("Upload PDFs") as upload_tab:
            uploaded_files = gr.Files(label="Upload at least one PDF", type="filepath")
            with gr.Row():
                upload_button = gr.Button("Upload")  # Upload button is visible initially
                upload_status = gr.Textbox(visible=False)

        with gr.TabItem("Chat", visible=False) as chat_tab:
            question = gr.Textbox(label="Ask a Question", placeholder="Enter your question here...")
            submit_btn = gr.Button("Submit")
            rag_reply = gr.Chatbot(label="RAG Reply")

        with gr.TabItem("History"):
            history_markdown = gr.Markdown("No chat history yet.")

    chat_history = gr.State([])

    def activate_chat_tab():
        return gr.Tabs.update(selected=1)

    def upload_pdfs(files):
        # Simulate an upload process (replace with your actual logic)
        # time.sleep(2)
        if files:
            return gr.update(visible=True, value="Upload finished!"), gr.update(visible=True)
        else:
            return gr.update(visible=True, value="Please upload at least one PDF file."), gr.update(visible=False)

    upload_button.click(
        upload_pdfs,
        inputs=uploaded_files,
        outputs=[upload_status, chat_tab],
    )

    upload_button.click(
        fn=activate_chat_tab,
        inputs=None,
        outputs=tabs,
    )

    upload_status.change(
        fn=lambda: gr.update(visible=False),
        inputs=None,
        outputs=[upload_status],
    )

    submit_btn.click(
        fn=process_question,
        inputs=[question, chat_history, uploaded_files],
        outputs=[chat_history, rag_reply],
    )

    chat_history.change(
        fn=lambda x: gr.Markdown("<br>".join([f"**Question:** {q}<br>**Answer:** {a}" for q, a in x])),
        inputs=chat_history,
        outputs=history_markdown,
    )

demo.launch()