agent.py

import os
from dotenv import load_dotenv
from typing import TypedDict, List, Dict, Any, Optional
from langgraph.graph import StateGraph, START, END, MessagesState
from langchain.agents import create_tool_calling_agent, ConversationalAgent, AgentExecutor, initialize_agent, create_react_agent
from langchain_google_genai import ChatGoogleGenerativeAI
from langchain_groq import ChatGroq
from langchain_core.tools import tool
from langchain_core.messages import HumanMessage, SystemMessage
from langchain.memory import ConversationBufferMemory
from langchain_core.prompts import ChatPromptTemplate, PromptTemplate
from langgraph.prebuilt import ToolNode
from langgraph.prebuilt import tools_condition

# 1. Web Browsing
from langchain_community.tools import DuckDuckGoSearchResults
from langchain_community.document_loaders import ImageCaptionLoader
import requests, time
import pandas as pd
from pathlib import Path
from langchain_community.tools import WikipediaQueryRun
from langchain_community.utilities import WikipediaAPIWrapper
from langchain_community.document_loaders import YoutubeLoader
from langchain_community.document_loaders import UnstructuredExcelLoader
from langchain_community.document_loaders import AssemblyAIAudioTranscriptLoader
from langchain.text_splitter import CharacterTextSplitter
from langchain_community.utilities import GoogleSerperAPIWrapper

load_dotenv()
DEFAULT_API_URL = "https://agents-course-unit4-scoring.hf.space"

@tool
def duckduck_websearch(query: str) -> str:
    """Allows search through DuckDuckGo.
    Args:
        query: what you want to search
    """
    search = DuckDuckGoSearchResults()
    results = search.invoke(query)
    return "\n".join(results)

@tool
def serper_websearch(query: str) -> str:
    """Allows search through Serper.
    Args:
        query: what you want to search
    """
    search = GoogleSerperAPIWrapper(serper_api_key=os.getenv("SERPER_API_KEY"))
    results = search.run(query)
    return results

@tool
def visit_webpage(url: str) -> str:
    """Fetches raw HTML content of a web page.
    Args:
        url: the webpage url
    """
    try:
        response = requests.get(url, timeout=5)
        return response.text[:5000]
    except Exception as e:
        return f"[ERROR fetching {url}]: {str(e)}"

@tool
def wiki_search(query: str) -> str:
    """Wiki search tools.
    Args:
        query: what you want to wiki
    """
    api_wrapper = WikipediaAPIWrapper(top_k_results=1, doc_content_chars_max=100)
    wikipediatool = WikipediaQueryRun(api_wrapper=api_wrapper)
    return wikipediatool.run({"query": query})

@tool
def text_splitter(text: str) -> List[str]:
    """Splits text into chunks using LangChain's CharacterTextSplitter.
    Args:
        text: A string of text to split.
    """
    splitter = CharacterTextSplitter(chunk_size=450, chunk_overlap=10)
    return splitter.split_text(text)

@tool
def youtube_transcript(video_url: str) -> str:
    """Fetched youtube transcript
    Args:
        video_url: YouTube video url
    """
    try:
        loader = YoutubeLoader.from_youtube_url(video_url)
        # video_id = video_url.split("v=")[-1].split("&")[0]
        # transcript = YouTubeTranscriptApi.get_transcript(video_id)
        return loader.load()
    except Exception as e:
        return f"Error fetching transcript: {str(e)}"

# 4. File Reading
@tool
def read_file(task_id: str) -> str:
    """First download the file, then read its content
    Args:
        dir: the task_id
    """
    file_url = f'{DEFAULT_API_URL}/files/{task_id}'
    r = requests.get(file_url, timeout=15, allow_redirects=True)
    with open('temp', "wb") as fp:
        fp.write(r.content)
    with open('temp') as f:
        return f.read()

@tool
def excel_read(task_id: str) -> str:
    """First download the excel file, then read its content
    Args:
        dir: the task_id
    """
    try:
        file_url = f'{DEFAULT_API_URL}/files/{task_id}'
        r = requests.get(file_url, timeout=15, allow_redirects=True)
        with open('temp.xlsx', "wb") as fp:
            fp.write(r.content)
        # Read the Excel file
        df = pd.read_excel('temp.xlsx')
        # Run various analyses based on the query
        result = (
            f"Excel file loaded with {len(df)} rows and {len(df.columns)} columns.\n"
        )
        result += f"Columns: {', '.join(df.columns)}\n\n"
        # Add summary statistics
        result += "Summary statistics:\n"
        result += str(df.describe())
        return result
    except Exception as e:
        return f"Error analyzing Excel file: {str(e)}"
   
@tool
def csv_read(task_id: str) -> str:
    """First download the csv file, then read its content
    Args:
        dir: the task_id
    """
    try:
        file_url = f'{DEFAULT_API_URL}/files/{task_id}'
        r = requests.get(file_url, timeout=15, allow_redirects=True)
        with open('temp.csv', "wb") as fp:
            fp.write(r.content)
        # Read the CSV file
        df = pd.read_csv(temp.csv)
        # Run various analyses based on the query
        result = (
            f"Excel file loaded with {len(df)} rows and {len(df.columns)} columns.\n"
        )
        result += f"Columns: {', '.join(df.columns)}\n\n"
        # Add summary statistics
        result += "Summary statistics:\n"
        result += str(df.describe())
        return result
    except Exception as e:
        return f"Error analyzing CSV file: {str(e)}"
        
@tool
def mp3_listen(task_id: str) -> str:
    """First download the mp3 file, then listen to it
    Args:
        dir: the task_id
    """
    file_url = f'{DEFAULT_API_URL}/files/{task_id}'
    r = requests.get(file_url, timeout=15, allow_redirects=True)
    with open('temp.mp3', "wb") as fp:
        fp.write(r.content)
    loader = AssemblyAIAudioTranscriptLoader(file_path="temp.mp3", api_key=os.getenv("AssemblyAI_API_KEY"))
    docs = loader.load()
    contents = [doc.page_content for doc in docs]
    return "\n".join(contents)
    
# 5. Image Open
@tool
def image_caption(dir: str) -> str:
    """Understand the content of the provided image
    Args:
        dir: the image url link
    """
    loader = ImageCaptionLoader(images=[dir])
    metadata = loader.load()
    return metadata[0].page_content

# 2. Coding
from langchain_experimental.tools import PythonREPLTool
@tool
def run_python(code: str):
    """ Run the given python code
    Args:
        code: the python code
    """
    return PythonREPLTool().run(code)

@tool
def multiply(a: float, b: float) -> float:
    """Multiply two numbers.
    Args:
        a: first float
        b: second float
    """
    return a * b

@tool
def add(a: float, b: float) -> float:
    """Add two numbers.
    Args:
        a: first float
        b: second float
    """
    return a + b

@tool
def subtract(a: float, b: float) -> float:
    """Subtract two numbers.
    Args:
        a: first float
        b: second float
    """
    return a - b

@tool
def divide(a: float, b: float) -> float:
    """Divide two numbers.
    Args:
        a: first float
        b: second float
    """
    if b == 0:
        raise ValueError("Cannot divide by zero.")
    return a / b

# 3. Multi-Modality
# - multiply: multiply two numbers, A and B
# - add: add two numbers, A and B
# - subtract: Subtract A by B with passing A as the first argument
# - divide: Divide A by B with passing A as the first argument



# ("human", f"Question: {question}\nReport to validate: {final_answer}")
class BasicAgent:
    def __init__(self):
        self.model = ChatGoogleGenerativeAI(
            model="gemini-2.0-flash-lite",
            temperature=0,
            max_tokens=1024,
            candidate_count=1,
            google_api_key=os.getenv("GEMINI_API_KEY"),
        )
        # System Prompt for few shot prompting
        self.sys_prompt = """"
                You are a general AI assistant. I will ask you a question. Report your thoughts, and finish your answer with the following template: 
                FINAL ANSWER: [YOUR FINAL ANSWER].
                YOUR FINAL ANSWER should be a number OR as few words as possible OR a comma separared list of numbers and/or strings.
                If you are asked for a number, don't use comma to write your number neither use units such as $ or percent sign unless specified otherwise.
                If you are asked for a string, don't use articles, neither abbreviations (eg. for cities), and write the digits in plain text unless specified otherwise.
                If you are asked for a comma separated list, apply the above rules depending of whether the element to put in the list is a number or a string.

                You have access to the following tools:
                - serper_websearch: web search the content of the query by passing the query as input with Serper Search Engine
                - duckduck_websearch: web search the content of the query by passing the query as input with DuckDuckGo Search Engine
                - visit_webpage: visit the given webpage url by passing the url as input
                - wiki_search: wiki search the content of the query by passing the query as input if the question asks for wiki search it
                - text_splitter: split text into chunks
                - youtube_transcript: fetch the transcript of the Youtube video by passing the video url as input if the question asks for watching a Youtube video
                - read_file: read the content of the attached file by passing the TASK-ID as input
                - excel_read: read the content of the attached excel file by passing the TASK-ID as input
                - csv_read: read the content of the attached csv file by passing the TASK-ID as input
                - mp3_listen: listen to the content of the attached mp3 file by passing the TASK-ID as input
                - image_caption: understand the visual content of the attached image by passing the TASK-ID as input
                - run_python: run the python code
                
                If Task ID is included in the question, remember to call the relevant read tools [ie. read_file, excel_read, csv_read, mp3_listen, image_caption]
                Note: python_tool is called when the question mentions the term "Python" or any math calculation.
        """
        self.tools = [duckduck_websearch, serper_websearch, visit_webpage, wiki_search, text_splitter, youtube_transcript, read_file, excel_read, csv_read, mp3_listen, image_caption, run_python]
        # Setup memory
        self.memory = ConversationBufferMemory(
            memory_key="chat_history",
            return_messages=True
        )
        self.agent = self.__setup__agent__()
        # self.prompt = ChatPromptTemplate.from_messages([
        #     ("system", self.sys_prompt),
        #     ("human", "{input}")
        # ])

        # self.agent = initialize_agent(
        #     tools=self.tools,
        #     llm=self.model,
        #     agent="zero-shot-react-description",  # ReAct agent type
        #     verbose=True,
        #     system_prompt=self.prompt,
        #     handle_parsing_errors=True,
        #     max_iterations=30
        #     # "Check your output and make sure it conforms, use the Action/Action Input syntax"
        # )
        print("BasicAgent initialized.")
    
    def __call__(self, task: dict) -> str:
        task_id, question, file_name = task["task_id"], task["question"], task["file_name"]
        print(f"Agent received question (first 50 chars): {question[:50]}...")
        
        if file_name == "" or file_name is None:
            question = question
        else:
            question = f"{question} with TASK-ID: {task_id}"
            # fixed_answer = self.agent.run(f'{question} with TASK-ID: {task_id}')
        fixed_answer = "This is a default answer."
        

        max_retries = 3
        base_sleep = 1
        for attempt in range(max_retries):
            try:
                fixed_answer = self.agent.run(question)
                print(f"Agent returning fixed answer: {fixed_answer}")
                time.sleep(60)
                return fixed_answer
            except Exception as e:
                sleep_time = base_sleep * (attempt + 1)
                if attempt < max_retries - 1:
                    print(f"Attempt {attempt + 1} failed. Retrying in {sleep_time} seconds...")
                    time.sleep(sleep_time)
                    continue
                return f"Error processing query after {max_retries} attempts: {str(e)}"
        return fixed_answer

    def __setup__agent__(self) -> AgentExecutor:
        PREFIX = """
                You are a general AI assistant that can use various tools to answer question. I will ask you a question. Report your thoughts, and finish your answer with the following template: 
                FINAL ANSWER: [YOUR FINAL ANSWER].
                YOUR FINAL ANSWER should be a number OR as few words as possible OR a comma separared list of numbers and/or strings.
                If you are asked for a number, don't use comma to write your number neither use units such as $ or percent sign unless specified otherwise.
                If you are asked for a string, don't use articles, neither abbreviations (eg. for cities), and write the digits in plain text unless specified otherwise.
                If you are asked for a comma separated list, apply the above rules depending of whether the element to put in the list is a number or a string.

                NOTE:
                - If Task ID is included in the question, remember to call the relevant read tools [ie. read_file, excel_read, csv_read, mp3_listen, image_caption]
                - python_tool is called when the question mentions the term "Python" or any math calculation.
        """
        FORMAT_INSTRUCTIONS = """
                To use a tool, use the following format:
                Thought: Do I need to use a tool? Yes
                Action: the action to take, should be one of [{tool_names}]
                Action Input: the input to the action
                Observation: the result of the action
                When you have a response to say to the Human, or if you do not need to use a tool, you MUST use the format:
                Thought: Do I need to use a tool? No
                Final Answer: [your response here]
                Begin! Remember to ALWAYS include 'Thought:', 'Action:', 'Action Input:', and 'Final Answer:' in your responses.
        """
        SUFFIX = """
                Previous conversation history:
                {chat_history}
                New question: {input}
                {agent_scratchpad}
        """
        agent = ConversationalAgent.from_llm_and_tools(
            llm=self.model,
            tools=self.tools,
            prefix=PREFIX,
            format_instructions=FORMAT_INSTRUCTIONS,
            suffix=SUFFIX,
            input_variables=["input", "chat_history", "agent_scratchpad", "tool_names"],
            handle_parsing_errors=True
        )
        return AgentExecutor.from_agent_and_tools(
            agent=agent,
            tools=self.tools,
            memory=self.memory,
            max_iterations=5,
            verbose=True,
            handle_parsing_errors=True,
            return_only_outputs=True  # This ensures we only get the final output
        )