agent.py

"""LangGraph Agent"""
import os
from dotenv import load_dotenv
from langgraph.graph import START, StateGraph, MessagesState
from langgraph.prebuilt import tools_condition
from langgraph.prebuilt import ToolNode
from langchain_google_genai import ChatGoogleGenerativeAI
from langchain_groq import ChatGroq
from langchain_huggingface import ChatHuggingFace, HuggingFaceEndpoint, HuggingFaceEmbeddings
from langchain_community.tools.tavily_search import TavilySearchResults
from langchain_community.document_loaders import WikipediaLoader
from langchain_community.document_loaders import ArxivLoader
from langchain_community.vectorstores import SupabaseVectorStore
from langchain_core.messages import SystemMessage, HumanMessage
from langchain_core.tools import tool
from langchain.tools.retriever import create_retriever_tool
from supabase.client import Client, create_client

from langchain.tools import Tool


load_dotenv()

def multiply(a: int, b: int) -> int:
    return a * b

multiply_tool = Tool(
    name="multiply",
    func=multiply,
    description="Multiply two numbers. Args (a: first int, b: second int)"
)

def add(a: int, b: int) -> int:
    return a + b

add_tool = Tool(
    name="add",
    func=add,
    description="Add two numbers. Args (a: first int, b: second int)"
)

def substract(a: int, b: int) -> int:
    return a - b

substract_tool = Tool(
    name="substract",
    func=substract,
    description="Substract two numbers. Args (a: first int, b: second int)"
)

def divide(a: int, b: int) -> int:
    if b == 0:
        raise ValueError("Cannot divide by zero.")
    return a / b

divide_tool = Tool(
    name="divide",
    func=divide,
    description="Divide two numbers. Args (a: first int, b: second int)"
)

def modulus(a: int, b: int) -> int:
    return a % b
    
modulus_tool = Tool(
    name="modulus",
    func=modulus,
    description="Modulus two numbers. Args (a: first int, b: second int)"
)

def wiki_search(query: str) -> str:
    search_docs = WikipediaLoader(query=query, load_max_docs=2).load()
    formatted_search_docs = "\n\n---\n\n".join(
        [
            f'<Document source="{doc.metadata["source"]}" page="{doc.metadata.get("page", "")}"/>\n{doc.page_content}\n</Document>'
            for doc in search_docs
        ])
    return {"wiki_results": formatted_search_docs}

wiki_search_tool = Tool(
    name="wiki_search",
    func=wiki_search,
    description="Search Wikipedia for a query and return maximum 2 results. Args (query: the search query)"
)

def web_search(query: str) -> str:
    search_docs = TavilySearchResults(max_results=3).invoke(query=query)
    formatted_search_docs = "\n\n---\n\n".join(
        [
            f'<Document source="{doc.metadata["source"]}" page="{doc.metadata.get("page", "")}"/>\n{doc.page_content}\n</Document>'
            for doc in search_docs
        ])
    return {"web_results": formatted_search_docs}
    
web_search_tool = Tool(
    name="web_search",
    func=web_search,
    description="Search Tavily for a query and return maximum 3 results. Args (query: the search query)"
)

def arvix_search(query: str) -> str:
    """Search Arxiv for a query and return maximum 3 result.
    
    Args:
        query: The search query."""
    search_docs = ArxivLoader(query=query, load_max_docs=3).load()
    formatted_search_docs = "\n\n---\n\n".join(
        [
            f'<Document source="{doc.metadata["source"]}" page="{doc.metadata.get("page", "")}"/>\n{doc.page_content[:1000]}\n</Document>'
            for doc in search_docs
        ])
    return {"arvix_results": formatted_search_docs}

arvix_search_tool = Tool(
    name="arvix_search",
    func=arvix_search,
    description="Search Arxiv for a query and return maximum 3 result. Args (query: the search query)"
)


# load the system prompt from the file
with open("system_prompt.txt", "r", encoding="utf-8") as f:
    system_prompt = f.read()

# System message
sys_msg = SystemMessage(content=system_prompt)

tools = [
    multiply_tool,
    add_tool,
    substract_tool,
    divide_tool,
    modulus_tool,
    wiki_search_tool,
    web_search_tool,
    arvix_search_tool,
]

# Build graph function
def build_graph(provider: str = "google"):
    """Build the graph"""
    # Load environment variables from .env file
    if provider == "google":
        # Google Gemini
        chat = ChatGoogleGenerativeAI(model="gemini-2.0-flash", temperature=0)
    elif provider == "groq":
        # Groq https://console.groq.com/docs/models
        chat = ChatGroq(model="qwen-qwq-32b", temperature=0) # optional : qwen-qwq-32b gemma2-9b-it
    elif provider == "huggingface":
        # TODO: Add huggingface endpoint
        chat = ChatHuggingFace(
            llm=HuggingFaceEndpoint(
                url="https://api-inference.huggingface.co/models/Meta-DeepLearning/llama-2-7b-chat-hf",
                temperature=0,
            ),
        )
    else:
        raise ValueError("Invalid provider. Choose 'google', 'groq' or 'huggingface'.")
    # Bind tools to LLM
    chat_with_tools = chat.bind_tools(tools)

    # Node
    def assistant(state: MessagesState):
        """Assistant node"""
        return {"messages": [llm_with_tools.invoke(state["messages"])]}
    
    # def retriever(state: MessagesState):
      #  """Retriever node"""
       # similar_question = vector_store.similarity_search(state["messages"][0].content)
        #example_msg = HumanMessage(
         #   content=f"Here I provide a similar question and answer for reference: \n\n{similar_question[0].page_content}",
       # )
       # return {"messages": [sys_msg] + state["messages"] + [example_msg]}

    from langchain_core.messages import AIMessage

    def retriever(state: MessagesState):
        query = state["messages"][-1].content
        similar_doc = vector_store.similarity_search(query, k=1)[0]

        content = similar_doc.page_content
        if "Final answer :" in content:
            answer = content.split("Final answer :")[-1].strip()
        else:
            answer = content.strip()

        return {"messages": [AIMessage(content=answer)]}

   # builder = StateGraph(MessagesState)
    #builder.add_node("retriever", retriever)
    #builder.add_node("assistant", assistant)
    #builder.add_node("tools", ToolNode(tools))
    #builder.add_edge(START, "retriever")
    #builder.add_edge("retriever", "assistant")
    #builder.add_conditional_edges(
     #   "assistant",
      #  tools_condition,
    #)
    #builder.add_edge("tools", "assistant")

    #builder = StateGraph(MessagesState)
    #builder.add_node("retriever", retriever)

    # Retriever ist Start und Endpunkt
    #builder.set_entry_point("retriever")
    #builder.set_finish_point("retriever")

    # Compile graph
    #return builder.compile()



    builder = StateGraph(MessagesState)
    # Define nodes: these do the work
    builder.add_node("assistant", assistant)
    builder.add_node("tools", ToolNode(tools))
    # Define edges: these determine how the control flow moves
    builder.add_edge(START, "assistant")
    builder.add_conditional_edges(
        "assistant",
        # If the latest message requires a tool, route to tools
        # Otherwise, provide a direct response
        tools_condition,
    )
    builder.add_edge("tools", "assistant")

    # Compile graph
    return builder.compile()