backend/app_v2.py

import gradio as gr
from rag import RAG  # Assuming your rag.py is in the same directory
import os
import time

# --- Configuration ---
GOOGLE_API_KEY = os.getenv("GOOGLE_API_KEY")
if not GOOGLE_API_KEY:
    raise ValueError("GOOGLE_API_KEY environment variable not set. Please set it before running the app.")

COLLECTION_NAME = os.getenv("COLLECTION_NAME", "ca_documents")

# --- Initialize RAG System ---
try:
    rag = RAG(GOOGLE_API_KEY, COLLECTION_NAME)
except Exception as e:
    print(f"Fatal Error initializing RAG system: {e}")
    raise

# --- Initial Chat State ---
welcome_message = {
    "role": "assistant",
    "content": """
👋 **Welcome to your CA Study Assistant!**
"""
}
initial_chat_history = [welcome_message]

# --- Core Functions ---
def upload_file(file):
    if file is None:
        return """<div class="message-bubble error">
            <p><strong>⚠️ Please select a file.</strong></p>
            <p>Supported formats: PDF, DOCX, TXT.</p>
        </div>"""
    try:
        start_time = time.time()
        file_path = file.name
        success = rag.upload_document(file_path)
        duration = time.time() - start_time
        if success:
            return f"""<div class=\"message-bubble success\">
                <p><strong>✅ Success!</strong></p>
                <p><em>{os.path.basename(file_path)}</em> uploaded.</p>
                <p><small>Processed in {duration:.2f}s</small></p>
            </div>"""
        else:
            return f"""<div class=\"message-bubble error\"><p><strong>❌ Upload Failed.</strong></p><p>Please ensure <em>{os.path.basename(file_path)}</em> is a valid file.</p></div>"""
    except Exception as e:
        return f"""<div class=\"message-bubble error\"><p><strong>❌ An Error Occurred</strong></p><p><small>{str(e)}</small></p></div>"""

def chat_with_docs(message: str, history: list):
    if not message or not message.strip():
        return "", history
    history.append({"role": "user", "content": message})
    answer = rag.ask_question(message)
    history.append({"role": "assistant", "content": answer})
    return "", history

def clear_chat():
    return initial_chat_history, ""

# --- Load Custom CSS ---
with open("style.css") as f:
    css = f.read()

# --- Gradio App Layout ---
with gr.Blocks(css=css, title="CA Study Assistant", theme=gr.themes.Base(), mode="auto") as app:
    with gr.Column(elem_id="app-container"):

        gr.HTML("""
            <div id="header">
                <h1>CA Study Assistant</h1>
                <p>The smartest way to study your materials.</p>
            </div>
        """)

        with gr.Tabs(elem_classes="tab-nav"):
            with gr.TabItem("💬 Ask Questions", id="chat_tab"):
                chatbot = gr.Chatbot(
                    value=initial_chat_history,
                    elem_id="chat-history",
                    show_label=False,
                    type="messages",
                    bubble_full_width=False,
                )
                with gr.Row(elem_id="chat-input-container"):
                    with gr.Column(scale=10):
                        chat_input = gr.Textbox(
                            placeholder="Ask anything about your documents...",
                            show_label=False, elem_id="chat-input", lines=1, max_lines=5,
                        )
                    with gr.Column(scale=1, min_width=60):
                        send_btn = gr.Button('➤', elem_id="send-btn")
                clear_btn = gr.Button("🗑️ Clear", elem_id="clear-btn")
                clear_btn.click(fn=clear_chat, outputs=[chatbot, chat_input])

            with gr.TabItem("📚 Upload Documents", id="upload_tab"):
                with gr.Column(elem_id="upload-area"):
                    gr.HTML("""
                        <div id="upload-icon">
                            <svg xmlns="http://www.w3.org/2000/svg" width="80" height="80" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M21 15v4a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2v-4"></path><polyline points="17 8 12 3 7 8"></polyline><line x1="12" y1="3" x2="12" y2="15"></line></svg>
                        </div>
                        <h3>Upload Your Study Materials</h3>
                        <p>Drag & drop or click below to select a file.</p>
                        <div style="margin-top: 0.5rem;">
                            <span style="background:#c7d2fe;color:#5046e5;padding:0.3rem 0.75rem;border-radius:999px;margin-right:0.5rem;">PDF</span>
                            <span style="background:#c7d2fe;color:#5046e5;padding:0.3rem 0.75rem;border-radius:999px;margin-right:0.5rem;">DOCX</span>
                            <span style="background:#c7d2fe;color:#5046e5;padding:0.3rem 0.75rem;border-radius:999px;">TXT</span>
                        </div>
                    """)
                    upload_input = gr.File(
                        label="", file_count="single", file_types=[".pdf", ".docx", ".txt"],
                        type="filepath",
                    )
                    upload_output = gr.HTML(elem_id="upload-output")

    upload_input.upload(
        fn=upload_file, inputs=[upload_input], outputs=[upload_output],
        api_name="upload_document"
    )
    send_btn.click(
        fn=chat_with_docs, inputs=[chat_input, chatbot], outputs=[chat_input, chatbot],
    )
    chat_input.submit(
        fn=chat_with_docs, inputs=[chat_input, chatbot], outputs=[chat_input, chatbot],
    )

if __name__ == "__main__":
    app.launch(share=True, debug=True)