import streamlit as st
from openai import OpenAI
from config import config
import requests
from prompts import SYSTEM_PROMPT


def setup_page():
    """Set up the Streamlit app's page configuration."""
    st.set_page_config(
        page_title="Ollama Chatbot",
        page_icon="🤖",
        layout="wide",
        initial_sidebar_state="auto",
    )


def initialize_session_state():
    """Initialize session state variables."""
    if "messages" not in st.session_state:
        st.session_state.messages = []
    if "ollama_server" not in st.session_state:
        st.session_state.ollama_server = config.OLLAMA_SERVER


def get_ollama_client():
    """Initialize the OpenAI client for Ollama."""
    base_url = f"{st.session_state.ollama_server}/v1/"
    return OpenAI(base_url=base_url, api_key="ollama")


def create_message(role, content):
    """Create a chat message dictionary."""
    return {"role": role, "content": content}


def fetch_chat_response(client, messages, model):
    """Fetch a response from the OpenAI client."""
    try:
        response = client.chat.completions.create(messages=messages, model=model)
        return response.choices[0].message.content
    except Exception as e:
        st.error(f"Error generating response: {e}")
        return None


def fetch_available_models(server_url):
    """Fetch available models from the Ollama server."""
    url = f"{server_url}/api/tags"
    try:
        response = requests.get(url)
        response.raise_for_status()
        return [item["model"] for item in response.json().get("models", [])]
    except requests.RequestException as e:
        st.error(f"Error fetching models: {e}")
        return []


def render_chat_messages():
    """Display chat messages in the UI."""
    for message in st.session_state.messages:
        role = message["role"]
        content = message["content"]
        if role == "user":
            st.chat_message("user").write(content)
        elif role == "assistant":
            st.chat_message("assistant").write(content)


def handle_user_input(client, model):
    """Handle user input and process responses."""
    if user_input := st.chat_input("Say something"):
        # Add system prompt if it's the first message
        if not st.session_state.messages:
            st.session_state.messages.append(create_message("system", SYSTEM_PROMPT))
        
        # Add user input to chat
        st.session_state.messages.append(create_message("user", user_input))
        st.chat_message("user").write(user_input)

        # Get assistant response
        response = fetch_chat_response(client, st.session_state.messages, model)
        if response:
            st.session_state.messages.append(create_message("assistant", response))
            st.chat_message("assistant").write(response)


def clear_chat():
    """Clear all chat messages."""
    st.session_state.messages = []


def sanitize_url(url):
    """Remove trailing slash from a URL if present."""
    return url.rstrip("/") if url.endswith("/") else url


def main():
    """Main function to run the chatbot application."""
    # Setup page and session state
    setup_page()
    initialize_session_state()
    
    # Initialize client
    client = get_ollama_client()

    # App Title
    st.title("Ollama Chatbot")
    st.sidebar.title("Settings")

    # Sidebar: Server and Models
    ollama_server = st.sidebar.text_input("Ollama Server", value=st.session_state.ollama_server)
    models = fetch_available_models(ollama_server)
    
    if not models:
        st.error("No models available. Please check the server connection.")
        return

    model = st.sidebar.selectbox("Select a Model", models)

    # Sidebar: System Prompt
    global SYSTEM_PROMPT
    updated_prompt = st.sidebar.text_area("System Prompt", value=SYSTEM_PROMPT)
    
    if st.sidebar.button("Update settings", use_container_width=True):
        st.session_state.ollama_server = sanitize_url(ollama_server)
        SYSTEM_PROMPT = updated_prompt
        
        # Update the system message if it exists, otherwise add it
        if st.session_state.messages and st.session_state.messages[0]["role"] == "system":
            st.session_state.messages[0]["content"] = SYSTEM_PROMPT
        elif not st.session_state.messages:
            st.session_state.messages.insert(0, create_message("system", SYSTEM_PROMPT))

    if st.sidebar.button("Clear Chat", use_container_width=True):
        clear_chat()

    # Main Chat Interface
    render_chat_messages()
    handle_user_input(client, model)


if __name__ == "__main__":
    main()