app.py

import PyPDF2
import re
from sentence_transformers import SentenceTransformer
import faiss
from langchain.agents import initialize_agent, AgentType,Tool
from langchain.schema import HumanMessage
from langchain_google_genai import ChatGoogleGenerativeAI
import gradio as gr
import os
import pytesseract
from PIL import Image
pytesseract.pytesseract.tesseract_cmd = r"tesseract.exe"



def load_pdf_text(file_path):
    with open(file_path, "rb") as file:
        reader = PyPDF2.PdfReader(file)
        text = ""
        for page in reader.pages:
            text += page.extract_text()
        return text

def chunk_text(text, chunk_size=700):
    # Splits the text into chunks of chunk_size while preserving sentences
    chunks = []
    sentences = re.split(r'(?<=[.!?])\s+', text)
    current_chunk = ""
    for sentence in sentences:
        if len(current_chunk) + len(sentence) > chunk_size:
            chunks.append(current_chunk)
            current_chunk = sentence
        else:
            current_chunk += " " + sentence
    chunks.append(current_chunk)
    return chunks


def load_and_process_chapters(directory):
    chapter_data = {}
    for filename in os.listdir(directory):
        if filename.endswith(".pdf"):
            file_path = os.path.join(directory, filename)
            text = load_pdf_text(file_path)
            chunks = chunk_text(text)
            chapter_data[filename] = chunks # Use filename as key
    return chapter_data

ipc_data = load_and_process_chapters("IPC") 
crpc_data=load_and_process_chapters("CrPC")
# Step 2: Embeddings and Indexing
model = SentenceTransformer('sentence-transformers/all-MiniLM-L6-v2')

index = faiss.IndexFlatL2(model.get_sentence_embedding_dimension())
index2 = faiss.IndexFlatL2(model.get_sentence_embedding_dimension())

# Flatten the chapter data and keep track of chapter and chunk indices
flattened_data = []
pdf_filenames = [] # Store PDF filenames for citation
chunk_indices = []
for pdf_filename, chunks in ipc_data.items():
    for i, chunk in enumerate(chunks):
        flattened_data.append(chunk)
        pdf_filenames.append(pdf_filename)
        chunk_indices.append(i)

embeddings = model.encode(flattened_data)
index.add(embeddings)

flattened_data2 = []
pdf_filenames2 = [] # Store PDF filenames for citation
chunk_indices2 = []
for pdf_filename, chunks in crpc_data.items():
    for i, chunk in enumerate(chunks):
        flattened_data2.append(chunk)
        pdf_filenames2.append(pdf_filename)
        chunk_indices2.append(i)

embeddings = model.encode(flattened_data2)
index2.add(embeddings)

# Step 3: Retrieval with Citations using PDF filename
def retrieve_info_with_citation(query, top_k=5):
    query_embedding = model.encode([query])
    D, I = index.search(query_embedding, k=top_k)

    results = []
    for i in range(min(top_k, len(I[0]))):
        if D[0][i] < 1.0:  # Relevance threshold
            chunk_index = I[0][i]
            pdf_filename = pdf_filenames[chunk_index]
            chunk_number = chunk_indices[chunk_index] + 1 
            match = flattened_data[chunk_index]
            citation = f"Source: {pdf_filename}, Chunk: {chunk_number}"
            results.append((match, citation))
        else:
            break

    if results:
        return results
    else:
        return [("I'm sorry, I couldn't find relevant information.", "Source: N/A")]


def retrieve_info_with_citation2(query, top_k=5):
    query_embedding = model.encode([query])
    D, I = index2.search(query_embedding, k=top_k)

    results = []
    for i in range(min(top_k, len(I[0]))):
        if D[0][i] < 1.0:  # Relevance threshold
            chunk_index = I[0][i]
            pdf_filename = pdf_filenames2[chunk_index]
            chunk_number = chunk_indices2[chunk_index] + 1 
            match = flattened_data2[chunk_index]
            citation = f"Source: {pdf_filename}, Chunk: {chunk_number}"
            results.append((match, citation))
        else:
            break

    if results:
        return results
    else:
        return [("I'm sorry, I couldn't find relevant information.", "Source: N/A")]

def retrieve_info(query):
    results = retrieve_info_with_citation(query)
    formatted_results = "\n\n".join([f"{i+1}. {match}\n{citation}" for i, (match, citation) in enumerate(results)])
    return formatted_results

def retrieve_info2(query):
    results = retrieve_info_with_citation2(query)
    formatted_results = "\n\n".join([f"{i+1}. {match}\n{citation}" for i, (match, citation) in enumerate(results)])
    return formatted_results

ipc_tool = Tool(
    name="IPC Information Retrieval",
    func=retrieve_info,
    description="Retrieve information from the Indian Penal Code Related to query keyword(s)."
)

crpc_tool=Tool(
    name="CrPC Information Retrieval",
    func=retrieve_info2,
    description="Retrieve information from the Code of Criminal Procedure(CrPC) Related to query keyword(s)."
)
llm = ChatGoogleGenerativeAI(
    model="gemini-1.5-pro",
    temperature=0.25,
    max_tokens=None,
    timeout=None,
    max_retries=2,
    prompt_template="""

    You are a highly specialized legal assistant with deep knowledge of the Indian Penal Code (IPC). 

    Your primary task is to retrieve and summarize legal information accurately from the IPC.pdf document provided to you. 

    Your responses should be highly specific, fact-based, and free from any speculation or hallucinations. 

    Always cite the exact section from the IPC when providing an answer. 

    If the information is not available in the document, clearly state that and do not make any assumptions.



    Example task: "What is the punishment for theft according to the IPC?"

    Example response: "According to Section 379 of the IPC, the punishment for theft is imprisonment of either description for a term which may extend to three years, or with fine, or with both."



    Task: {{query}}



    Response:

    """,
)

agent_tools = [ipc_tool,crpc_tool]

agent = initialize_agent(
    tools=agent_tools,
    llm=llm,
    agent=AgentType.STRUCTURED_CHAT_ZERO_SHOT_REACT_DESCRIPTION,
    verbose=True,
    return_intermediate_steps=True,
    handle_parsing_errors=True,
)
def encode_image_to_base64(image_path):
    return pytesseract.image_to_string(Image.open(image_path))
def chatbot_response(query):
    if query.get('files'):
        # Encode image to base64
        image_data=""
        for x in range(len(query["files"])):
            image_data += f"{x}. "+encode_image_to_base64(query["files"][x]) +"\n"
        
        # Create a multimodal message with both text and image data
        message = HumanMessage(
            content=[
                {"type": "text", "text": query['text'] +" System :Image(s) was added to this prompt by this user. Text Extracted from this image (Some words may be misspelled ,Use your understanding ):"+image_data},  # Add text input
               
            ]
        )
    else:
        # If no image, only pass the text
        message = HumanMessage(content=[{"type": "text", "text": query}])

    # Invoke the model with the multimodal message
    result = agent.invoke([message])
    response = result['output']
    intermediate_steps = result.get('intermediate_steps', [])
    
    thought_process = ""
    for action, observation in intermediate_steps:
        thought_process += f"**Thought:** {action.log}\n"
        thought_process += f"**Action:** {action.tool}\n"
        thought_process += f"**Observation:** {observation}\n\n"

    return response, thought_process.strip()
# Step 5: Gradio Interface
from gradio import ChatMessage
def chatbot_interface(messages,prompt):
    response, thought_process = chatbot_response(prompt)
    #messages.append(ChatMessage(role="user", content=prompt))
    
    for x in prompt["files"]:
            messages.append(ChatMessage(role="user", content={"path": x, "mime_type": "image/png"}))
    if prompt["text"] is not None:
            messages.append(ChatMessage(role="user", content=prompt['text']))
    if thought_process:
        messages.append(ChatMessage(role="assistant", content=thought_process,metadata={"title": "🧠 Thought Process"}))
    messages.append(ChatMessage(role="assistant", content=response))
   
    return messages,  gr.MultimodalTextbox(value=None, interactive=True)


def vote(data: gr.LikeData):
    if data.liked:
        print("You upvoted this response: " + data.value)
    else:
        print("You downvoted this response: " + data.value)

with gr.Blocks(theme=gr.themes.Soft()) as iface:
   
            gr.Markdown(
                """

                <div style="font-size: 24px; font-weight: bold; color: #333;">

                    DoJ Chatbot

                </div>

                <div style="font-size: 16px; color: #555;">

                    Ask questions related to the Department of Justice.

                </div>

                """
            )
            chatbot = gr.Chatbot(type="messages",avatar_images=("user.jpeg", "logo.jpeg"), bubble_full_width=True)  # Chatbot component to display conversation history
            query_input = gr.MultimodalTextbox(interactive=True,
                                      placeholder="Enter message or upload file...", show_label=False)
            submit_button = gr.Button("Send")

            submit_button.click(chatbot_interface, [chatbot, query_input], [chatbot, query_input])
            query_input.submit(chatbot_interface, [chatbot, query_input], [chatbot,query_input])

            chatbot.like(vote, None, None)  # Adding like/dislike functionality to the chatbot

        
iface.launch(
    show_error=True,
    prevent_thread_lock=True
)