src/streamlit_app.py

import os
import streamlit as st
from typing import Literal
from tavily import TavilyClient
from deepagents import create_deep_agent
from langgraph.store.memory import InMemoryStore
from langchain.chat_models import init_chat_model
from langchain_huggingface import ChatHuggingFace, HuggingFacePipeline

from langchain_community.callbacks.streamlit import (
    StreamlitCallbackHandler,
)

st.title("🦜🔗 Open DeepAgent App")
# --- Sidebar: API Keys ---
st.sidebar.header("🔑 API Keys")

tavily_api_key = st.sidebar.text_input("Tavily API Key", type="password", placeholder="sk-tavily-XXXX")
openai_api_key = st.sidebar.text_input("OpenAI API Key", type="password", placeholder="sk-openai-XXXX")
claude_api_key = st.sidebar.text_input("Anthropic API Key", type="password", placeholder="sk-ant-XXXX")
gemini_api_key = st.sidebar.text_input("Google Gemini API Key", type="password", placeholder="AIzaSyXXXX")

# --- Sidebar: Model Selection ---
st.sidebar.header("🧠 Choose Model Provider")
provider = st.sidebar.selectbox(
    "Select provider:",
    ["OpenAI", "Claude", "Gemini", "Hugging Face"],
    index=1,
)

# --- Editable system prompt ---
st.sidebar.header("🧩 Research Instructions")
research_instructions = st.sidebar.text_area(
    "System prompt for the agent:",
    value=(
        "You are an expert code researcher. Your job is to conduct thorough research, analyze complex information, "
        "and write a concise, well-structured report.\n\n"
        "You have access to an internet search tool as your primary method of gathering external information.\n"
        "## `internet_search`\n"
        "Use this function to query the web. Specify a topic, max results, and whether to include raw content."
    ),
    height=200,
)

# --- Store & Tavily Client ---
if not tavily_api_key:
    st.warning("Please enter your Tavily API key in the left menu to start the agent.")
    st.stop()

store = InMemoryStore()
tavily_client = TavilyClient(api_key=tavily_api_key)

# --- Web search tool ---
def internet_search(
    query: str,
    max_results: int = 5,
    topic: Literal["general", "news", "finance"] = "general",
    include_raw_content: bool = False,
):
    """
    Perform an internet search using the Tavily API.

    Args:
        query (str): The search query.
        max_results (int): Maximum number of results to return.
        topic (Literal["general", "news", "finance"]): Type of search to perform.
        include_raw_content (bool): Whether to include raw page content in results.

    Returns:
        dict: The structured search results from the Tavily API.
    """
    return tavily_client.search(
        query,
        max_results=max_results,
        include_raw_content=include_raw_content,
        topic=topic,
    )

# --- Model Loader ---
def load_model(provider: str):
    if provider == "OpenAI":
        if not openai_api_key:
            st.error("Please enter your OpenAI API key.")
            st.stop()
        os.environ["OPENAI_API_KEY"] = openai_api_key
        return init_chat_model(model="openai:gpt-5")

    elif provider == "Claude":
        if not claude_api_key:
            st.error("Please enter your Anthropic API key.")
            st.stop()
        os.environ["ANTHROPIC_API_KEY"] = claude_api_key
        return init_chat_model(model="claude-sonnet-4-5-20250929")

    elif provider == "Gemini":
        if not gemini_api_key:
            st.error("Please enter your Google Gemini API key.")
            st.stop()
        os.environ["GOOGLE_API_KEY"] = gemini_api_key
        return init_chat_model(model="gemini-2.5-pro")

    else:
        st.error("Unknown provider selected.")
        st.stop()

# --- Initialize Model ---
model = load_model(provider)

# --- Create the Deep Agent ---
agent = create_deep_agent(
    store=store,
    use_longterm_memory=True,
    model=model,
    tools=[internet_search],
    system_prompt=research_instructions,
)

# Initialize chat history
if "messages" not in st.session_state:
    st.session_state["messages"] = [
        {"role": "assistant", "content": "Hello! I’m your Deep Research Agent. What would you like to explore today?"}
    ]

# Display chat history
for msg in st.session_state.messages:
    with st.chat_message(msg["role"]):
        st.markdown(msg["content"])

# --- Chat Input ---

if prompt := st.chat_input("Ask your research question..."):
    # Save user message
    st.session_state.messages.append({"role": "user", "content": prompt})
    st.chat_message("user").write(prompt)

    # Process assistant response
    with st.chat_message("assistant"):
        st_callback = StreamlitCallbackHandler(st.container())
        response = agent.invoke(
            {"messages": st.session_state.messages},
            {"callbacks": [st_callback]},
        )

        # Extract and display assistant reply
        reply = response["messages"][-1].content
        st.markdown(reply)
        st.session_state.messages.append({"role": "assistant", "content": reply})