agent.py

import os
import logging
from typing import List, Dict, Any, Tuple
from langchain.tools import BaseTool
from langchain_core.messages import HumanMessage, AIMessage, SystemMessage
from langchain_core.prompts import ChatPromptTemplate, MessagesPlaceholder
from langchain_core.output_parsers import StrOutputParser
from langchain_core.runnables import RunnablePassthrough
from langchain_huggingface import HuggingFaceEndpoint
from langgraph.graph import START, StateGraph, MessagesState
from langgraph.prebuilt import tools_condition, ToolNode

from tools import WebSearchTool, WebContentTool, WikipediaSearchTool
#, AudioToTextTool, SpreadsheetParserTool, StringUtilitiesTool 

import config

# Configure logging
logging.basicConfig(
    level=logging.INFO,
    format='%(asctime)s - %(name)s - %(levelname)s - %(message)s',
    handlers=[logging.StreamHandler()]
)
logger = logging.getLogger("Agent")

class LangGraphAgent:
    """
    Advanced agent using LangGraph and the Qwen3-30B-A3B model
    """
    
    def __init__(self, verbose: bool = True):
        """
        Initialize the agent with its tools and configuration.
        """
        self.verbose = verbose
        
        # Initialize the model
        self.llm = HuggingFaceEndpoint(
            repo_id="Qwen/Qwen2.5-Coder-32B-Instruct",
            huggingfacehub_api_token=config.HUGGINGFACE_API_KEY,
            task="text-generation",
            temperature = config.TEMPERATURE
        )
        
        # Load tools
        self.tools = self._setup_tools()
        
        # Create the execution graph
        self.workflow = self._create_workflow()
    
    def _setup_tools(self) -> List[BaseTool]:
        """Configure and return the available tools for the agent"""
        tools = []
        
        # Add tools according to configuration
        if config.ENABLE_WEB_SEARCH:
            tools.append(WebSearchTool())
            tools.append(WebContentTool())
            
        if config.ENABLE_WIKIPEDIA_SEARCH:
            tools.append(WikipediaSearchTool())
            
        # if config.ENABLE_AUDIO_TO_TEXT:
        #     tools.append(AudioToTextTool())
            
        # if config.ENABLE_SPREADSHEET_PARSER:
        #     tools.append(SpreadsheetParserTool())
            
        # if config.ENABLE_STRING_UTILITIES:
        #     tools.append(StringUtilitiesTool())
        
        logger.info(f"Agent initialized with {len(tools)} tools")
        return tools
    
    def _create_workflow(self) -> StateGraph:
        """Create the agent's execution graph"""
        
        # Define the prompt
        prompt = ChatPromptTemplate.from_messages([
            ("system", config.DEFAULT_SYSTEM_MESSAGE),
            MessagesPlaceholder(variable_name="chat_history"),
            ("human", "{input}"),
            MessagesPlaceholder(variable_name="agent_scratchpad"),
        ])
        
        # Define the nodes
        def assistant(state: MessagesState):
            # Use the prompt to format messages
            messages = prompt.format_messages(
                chat_history=state["messages"][:-1],
                input=state["messages"][-1].content,
                agent_scratchpad=[]
            )
            return {"messages": [self.llm.invoke(messages)]}
        
        # Create the graph
        builder = StateGraph(MessagesState)
        
        # Add nodes
        builder.add_node("assistant", assistant)
        builder.add_node("tools", ToolNode(self.tools))
        
        # Add edges
        builder.add_edge(START, "assistant")
        builder.add_conditional_edges(
            "assistant",
            tools_condition,
        )
        builder.add_edge("tools", "assistant")
        
        # Compile the graph
        return builder.compile()
    
    def __call__(self, question: str) -> str:
        """
        Answer a question using the agent.
        
        Args:
            question: The question to answer
            
        Returns:
            The agent's answer
        """
        if not question.strip():
            return "Please ask a question."
            
        try:
            logger.info(f"Question received: {question[:50]}...")
            
            # Execute the workflow
            result = self.workflow.invoke({
                "messages": [HumanMessage(content=question)]
            })
            
            # Extract the final answer
            final_message = result["messages"][-1].content
            # if "FINAL ANSWER:" in final_message:
            #     return final_message.split("FINAL ANSWER:")[1].strip()
            return final_message
            
        except Exception as e:
            logger.error(f"Error processing the question: {str(e)}")
            return f"Sorry, an error occurred: {str(e)}" 

if __name__ == "__main__":
    # Create an instance of the agent
    agent = LangGraphAgent(verbose=True)
    
    # Question to test
    question = "How many studio albums were published by Mercedes Sosa between 2000 and 2009 (included)? You can use the latest 2022 version of english wikipedia."
    
    # Get the answer
    response = agent(question)
    
    # Display the answer
    print("\nQuestion:", question)
    print("\nAnswer:", response) 

    # Question to test
    question = ".rewsna eht sa \"tfel\" drow eht fo etisoppo eht etirw ,ecnetnes siht dnatsrednu uoy fI"
    
    # Obtenir la réponse
    response = agent(question)
    # Afficher la réponse
    print("\nQuestion:", question)
    print("\nRéponse:", response)