langchain_agent.py

import re
import constants
import time
from langchain_google_genai import ChatGoogleGenerativeAI
from langchain.agents import AgentExecutor, create_tool_calling_agent
from langchain_core.prompts import ChatPromptTemplate, MessagesPlaceholder
from langchain_core.messages import SystemMessage

# --- Custom Tools ---
from wikipedia_tool import wikipedia_revision_by_year_keyword
from count_max_bird_species_tool import count_max_bird_species_in_video
from image_to_text_tool import image_to_text
from internet_search_tool import internet_search
from botanical_classification_tool import get_botanical_classification
from excel_parser_tool import parse_excel

class LangChainAgent:
    def __init__(self):
        llm = ChatGoogleGenerativeAI(
            model=constants.MODEL,
            api_key=constants.API_KEY, 
            temperature=0.7)

        tools = [
            wikipedia_revision_by_year_keyword,
            count_max_bird_species_in_video,
            image_to_text,
            internet_search,
            get_botanical_classification,
            parse_excel
        ]

        prompt = ChatPromptTemplate.from_messages([
            SystemMessage(content=constants.PROMPT_LIMITADOR_LLM),
            MessagesPlaceholder(variable_name="chat_history"),
            ("human", "{input}"),
            MessagesPlaceholder(variable_name="agent_scratchpad"),
        ])

        agent = create_tool_calling_agent(llm, tools, prompt=prompt)
        self.executor = AgentExecutor(agent=agent, tools=tools, verbose=True)

    def __call__(self, question: str) -> str:
        print(f"LangChain agent received: {question[:50]}...")
        result = self.executor.invoke({
            "input": question,
            "chat_history": []
        })
        output = result.get("output", "No answer returned.")
        print(f"Agent response: {output}")
        match = re.search(r"FINAL ANSWER:\s*(.*)", output)
        if match:
            return match.group(1).strip()
        else:
            return output