import gradio as gr
from pdf_bot import create_qa_chain_from_pdf

qa_chain = None  # Global chain reference

css = """
#chatbot { 
    height: 350px; 
    overflow: auto; 
    border-radius: 10px;
    border: 1px solid #e0e0e0;
}
.textbox {
    border-radius: 20px !important;
    padding: 12px 20px !important;
}
.btn-column {
    display: flex;
    flex-direction: column;
    gap: 10px;
}
"""

def upload_pdf(pdf_file):
    global qa_chain
    try:
        qa_chain = create_qa_chain_from_pdf(pdf_file.name)
        return gr.update(visible=True), f"✅ PDF `{pdf_file.name}` loaded successfully!"
    except Exception as e:
        return gr.update(visible=False), f"❌ Error: {e}"

def respond(message, chat_history):
    global qa_chain
    if qa_chain is None:
        return message, chat_history + [[message, "⚠️ Please upload a PDF first."]]
    try:
        result = qa_chain({"query": message})
        answer = result["result"]
        chat_history.append((message, answer))
        return "", chat_history
    except Exception as e:
        return "", chat_history + [[message, f"❌ Error: {e}"]]

def create_interface():
    with gr.Blocks(css=css, theme="soft") as demo:
        gr.Markdown("""
            <h1 style='text-align: center;'>📘 University of Education Lahore PDF Chatbot</h1>
            <p style='text-align: center;'>Upload a university prospectus or document and ask anything!</p>
        """)

        pdf_input = gr.File(label="Upload PDF", type="file", file_types=[".pdf"])
        status = gr.Markdown()

        chatbot = gr.Chatbot(elem_id="chatbot", visible=False)

        examples = [
            "What are the admission requirements?",
            "How can I contact the administration?",
            "What programs are offered?"
        ]

        with gr.Row():
            message = gr.Textbox(
                label="Type your question here",
                placeholder="Ask about the uploaded PDF...",
                elem_classes="textbox",
                scale=4
            )
            with gr.Column(scale=1, elem_classes="btn-column"):
                submit_button = gr.Button("↩️ Enter")
                reset_button = gr.Button("🗑️ Reset Chat")

        pdf_input.change(upload_pdf, inputs=[pdf_input], outputs=[chatbot, status])
        message.submit(respond, [message, chatbot], [message, chatbot])
        submit_button.click(respond, [message, chatbot], [message, chatbot])
        reset_button.click(lambda: [], None, chatbot)

        gr.Examples(examples, inputs=message)

    return demo

if __name__ == "__main__":
    demo = create_interface()
    demo.launch()