import spaces
import gradio as gr
from transformers import AutoModelForCausalLM, AutoTokenizer, TextStreamer
import torch
import random

# Define model parameters for 8-bit quantized loading
model_name = "AstroMLab/AstroSage-8B"

# Load the tokenizer
tokenizer = AutoTokenizer.from_pretrained(model_name)

# Load the model with 8-bit quantization using bitsandbytes
model = AutoModelForCausalLM.from_pretrained(
    model_name,
    torch_dtype=torch.float16,
    load_in_8bit=True,               # Enable 8-bit quantization
    device_map="auto"                # Automatically assign layers to available GPUs
)

streamer = TextStreamer(tokenizer)

# Placeholder responses for when context is empty
GREETING_MESSAGES = [
    "Greetings! I am AstroSage, your guide to the cosmos. What would you like to explore today?",
    "Welcome to our cosmic journey! I am AstroSage. How may I assist you in understanding the universe?",
    "AstroSage here. Ready to explore the mysteries of space and time. How may I be of assistance?",
    "The universe awaits! I'm AstroSage. What astronomical wonders shall we discuss?",
]

def user(user_message, history):
    """Add user message to chat history."""
    if history is None:
        history = []
    return "", history + [{"role": "user", "content": user_message}]

@spaces.GPU(duration=20)
def bot(history):
    """Generate the chatbot response."""
    
    if not history:
        history = []
    
    # Prepare input prompt for the model
    system_prompt = (
        "You are AstroSage, an intelligent AI assistant specializing in astronomy, astrophysics, and cosmology. "
        "Provide accurate, scientific information while making complex concepts accessible. "
        "You're enthusiastic about space exploration and maintain a sense of wonder about the cosmos."
    )
    
    # Construct the chat history as a single input string
    prompt = system_prompt + "\n\n"
    for message in history:
        if message["role"] == "user":
            prompt += f"User: {message['content']}\n"
        else:
            prompt += f"AstroSage: {message['content']}\n"
    prompt += "AstroSage: "

    # Generate response
    inputs = tokenizer(prompt, return_tensors="pt").to(model.device)
    outputs = model.generate(
        **inputs,
        max_new_tokens=512,
        temperature=0.7,
        top_p=0.95,
        do_sample=True,
        streamer=streamer
    )

    # Decode the generated output and update history
    response_text = tokenizer.decode(outputs[0], skip_special_tokens=True)
    response_text = response_text[len(prompt):].strip()
    history.append({"role": "assistant", "content": response_text})
    yield history
    
def initial_greeting():
    """Return properly formatted initial greeting."""
    return [{"role": "assistant", "content": random.choice(GREETING_MESSAGES)}]

# Custom CSS for a space theme
custom_css = """
#component-0 {
    background-color: #1a1a2e;
    border-radius: 15px;
    padding: 20px;
}
.dark {
    background-color: #0f0f1a;
}
.contain {
    max-width: 1200px !important;
}
"""

# Create the Gradio interface
with gr.Blocks(css=custom_css, theme=gr.themes.Soft(primary_hue="indigo", neutral_hue="slate")) as demo:
    gr.Markdown(
        """
        # 🌌 AstroSage: Your Cosmic AI Companion
        
        Welcome to AstroSage, an advanced AI assistant specializing in astronomy, astrophysics, and cosmology. 
        Powered by the AstroSage-Llama-3.1-8B model, I'm here to help you explore the wonders of the universe!
        
        ### What Can I Help You With?
        - 🪐 Explanations of astronomical phenomena
        - 🚀 Space exploration and missions
        - ⭐ Stars, galaxies, and cosmology
        - 🌍 Planetary science and exoplanets
        - 📊 Astrophysics concepts and theories
        - 🔭 Astronomical instruments and observations
        
        Just type your question below and let's embark on a cosmic journey together!
        """
    )
    
    chatbot = gr.Chatbot(
        label="Chat with AstroSage",
        bubble_full_width=False,
        show_label=True,
        height=450,
        type="messages"
    )
    
    with gr.Row():
        msg = gr.Textbox(
            label="Type your message here",
            placeholder="Ask me anything about space and astronomy...",
            scale=9
        )
        clear = gr.Button("Clear Chat", scale=1)
    
    # Example questions for quick start
    gr.Examples(
        examples=[
            "What is a black hole and how does it form?",
            "Can you explain the life cycle of a star?",
            "What are exoplanets and how do we detect them?",
            "Tell me about the James Webb Space Telescope.",
            "What is dark matter and why is it important?"
        ],
        inputs=msg,
        label="Example Questions"
    )
    
    # Set up the message chain with streaming
    msg.submit(
        user,
        [msg, chatbot],
        [msg, chatbot],
        queue=False
    ).then(
        bot,
        chatbot,
        chatbot
    )
    
    # Clear button functionality
    clear.click(lambda: None, None, chatbot, queue=False)
    
    # Initial greeting
    demo.load(initial_greeting, None, chatbot, queue=False)

# Launch the app
if __name__ == "__main__":
    demo.launch()