app.py

import os
import subprocess

subprocess.run(["pip", "install", "-q", "pymupdf", "langchain", "langchain_community", "sentence-transformers", "faiss-cpu", "llama-cpp-python", "gradio", "transformers", "rank_bm25"], check=True)
subprocess.run(["curl", "--proto", "=https", "--tlsv1.2", "-sSf", "https://sh.rustup.rs | sh"], check=True)
subprocess.run("source $HOME/.cargo/env", shell=True, check=True)
subprocess.run(["pip", "install", "-q", "git+https://github.com/chroma-core/chroma.git"], check=True)
subprocess.run(["wget", "-q", "-O", "models/mistral-7b-instruct-v0.3.Q8_0.gguf", "https://huggingface.co/MaziyarPanahi/Mistral-7B-Instruct-v0.3-GGUF/resolve/main/Mistral-7B-Instruct-v0.3.Q8_0.gguf"])

os.makedirs("pdfs", exist_ok=True)
os.makedirs("models", exist_ok=True)

import re
import fitz  # PyMuPDF
import numpy as np
import gc
import torch
import time
import shutil
import hashlib
import pickle
import traceback
from typing import List, Dict, Any, Tuple, Optional, Union, Generator
from dataclasses import dataclass
from langchain.text_splitter import RecursiveCharacterTextSplitter
from langchain_community.vectorstores import FAISS
from langchain_community.embeddings import HuggingFaceEmbeddings
from llama_cpp import Llama
import gradio as gr
from rank_bm25 import BM25Okapi
import nltk
from nltk.tokenize import word_tokenize
from nltk.corpus import stopwords
from sentence_transformers import CrossEncoder

# Download nltk resources
try:
    nltk.download('punkt', quiet=True)
    nltk.download('stopwords', quiet=True)
except:
    print("Failed to download NLTK resources, continuing without them")

# === MEMORY MANAGEMENT UTILITIES ===
def clear_memory():
    """Clear memory to prevent OOM errors"""
    gc.collect()
    torch.cuda.empty_cache() if torch.cuda.is_available() else None

# === PDF PROCESSING ===
@dataclass
class PDFChunk:
    """Class to represent a chunk of text extracted from a PDF"""
    text: str
    source: str
    page_num: int
    chunk_id: int

class PDFProcessor:
    def __init__(self, pdf_dir: str = "pdfs"):
        """Initialize PDF processor

        Args:
            pdf_dir: Directory containing PDF files
        """
        self.pdf_dir = pdf_dir
        # Smaller chunk size with more overlap for better retrieval
        self.text_splitter = RecursiveCharacterTextSplitter(
            chunk_size=384,
            chunk_overlap=288,  # 75% overlap for better context preservation
            length_function=len,
            is_separator_regex=False,
        )

        # Create cache directory
        self.cache_dir = os.path.join(os.getcwd(), "pdf_cache")
        os.makedirs(self.cache_dir, exist_ok=True)

    def list_pdfs(self) -> List[str]:
        """List all PDF files in the directory"""
        if not os.path.exists(self.pdf_dir):
            return []
        return [f for f in os.listdir(self.pdf_dir) if f.lower().endswith('.pdf')]

    def _get_cache_path(self, pdf_path: str) -> str:
        """Get the cache file path for a PDF"""
        pdf_hash = hashlib.md5(open(pdf_path, 'rb').read(8192)).hexdigest()
        return os.path.join(self.cache_dir, f"{os.path.basename(pdf_path)}_{pdf_hash}.pkl")

    def _is_cached(self, pdf_path: str) -> bool:
        """Check if a PDF is cached"""
        cache_path = self._get_cache_path(pdf_path)
        return os.path.exists(cache_path)

    def _load_from_cache(self, pdf_path: str) -> List[PDFChunk]:
        """Load chunks from cache"""
        cache_path = self._get_cache_path(pdf_path)
        try:
            with open(cache_path, 'rb') as f:
                return pickle.load(f)
        except:
            return None

    def _save_to_cache(self, pdf_path: str, chunks: List[PDFChunk]) -> None:
        """Save chunks to cache"""
        cache_path = self._get_cache_path(pdf_path)
        try:
            with open(cache_path, 'wb') as f:
                pickle.dump(chunks, f)
        except Exception as e:
            print(f"Warning: Failed to cache PDF {pdf_path}: {str(e)}")

    def clean_text(self, text: str) -> str:
        """Clean extracted text"""
        # Remove excessive whitespace
        text = re.sub(r'\s+', ' ', text).strip()
        # Remove header/footer patterns (common in PDFs)
        text = re.sub(r'(?<!\w)page \d+(?!\w)', '', text, flags=re.IGNORECASE)
        return text

    def extract_text_from_pdf(self, pdf_path: str) -> List[PDFChunk]:
        """Extract text content from a PDF file with improved extraction

        Args:
            pdf_path: Path to the PDF file

        Returns:
            List of PDFChunk objects extracted from the PDF
        """
        # Check cache first
        if self._is_cached(pdf_path):
            cached_chunks = self._load_from_cache(pdf_path)
            if cached_chunks:
                print(f"Loaded {len(cached_chunks)} chunks from cache for {os.path.basename(pdf_path)}")
                return cached_chunks

        try:
            doc = fitz.open(pdf_path)
            pdf_chunks = []
            pdf_name = os.path.basename(pdf_path)

            for page_num in range(len(doc)):
                page = doc.load_page(page_num)

                # Extract text with more options for better quality
                page_text = page.get_text("text", sort=True)
                # Try to extract text with alternative layout analysis if the text is too short
                if len(page_text) < 100:
                    try:
                        page_text = page.get_text("dict", sort=True)
                        # Convert dict to text
                        if isinstance(page_text, dict) and "blocks" in page_text:
                            extracted_text = ""
                            for block in page_text["blocks"]:
                                if "lines" in block:
                                    for line in block["lines"]:
                                        if "spans" in line:
                                            for span in line["spans"]:
                                                if "text" in span:
                                                    extracted_text += span["text"] + " "
                            page_text = extracted_text
                    except:
                        # Fallback to default extraction
                        page_text = page.get_text("text")

                # Clean the text
                page_text = self.clean_text(page_text)

                # Extract tables
                try:
                    tables = page.find_tables()
                    if tables and hasattr(tables, "tables"):
                        for table in tables.tables:
                            table_text = ""
                            for i, row in enumerate(table.rows):
                                row_cells = []
                                for cell in row.cells:
                                    if hasattr(cell, "rect"):
                                        cell_text = page.get_text("text", clip=cell.rect)
                                        cell_text = self.clean_text(cell_text)
                                        row_cells.append(cell_text)
                                if row_cells:
                                    table_text += " | ".join(row_cells) + "\n"

                            # Add table text to page text
                            if table_text.strip():
                                page_text += "\n\nTABLE:\n" + table_text
                except Exception as table_err:
                    print(f"Warning: Skipping table extraction for page {page_num}: {str(table_err)}")

                # Split the page text into chunks
                if page_text.strip():
                    page_chunks = self.text_splitter.split_text(page_text)

                    # Create PDFChunk objects
                    for i, chunk_text in enumerate(page_chunks):
                        pdf_chunks.append(PDFChunk(
                            text=chunk_text,
                            source=pdf_name,
                            page_num=page_num + 1,  # 1-based page numbering for humans
                            chunk_id=i
                        ))

                # Clear memory periodically
                if page_num % 10 == 0:
                    clear_memory()

            doc.close()

            # Cache the results
            self._save_to_cache(pdf_path, pdf_chunks)

            return pdf_chunks
        except Exception as e:
            print(f"Error extracting text from {pdf_path}: {str(e)}")
            return []

    def process_pdf(self, pdf_name: str) -> List[PDFChunk]:
        """Process a single PDF file and extract chunks

        Args:
            pdf_name: Name of the PDF file in the pdf_dir

        Returns:
            List of PDFChunk objects from the PDF
        """
        pdf_path = os.path.join(self.pdf_dir, pdf_name)
        return self.extract_text_from_pdf(pdf_path)

    def process_all_pdfs(self, batch_size: int = 3) -> List[PDFChunk]:
        """Process all PDFs in batches to manage memory

        Args:
            batch_size: Number of PDFs to process in each batch

        Returns:
            List of all PDFChunk objects from all PDFs
        """
        all_chunks = []
        pdf_files = self.list_pdfs()

        if not pdf_files:
            print("No PDF files found in the directory.")
            return []

        # Process PDFs in batches
        for i in range(0, len(pdf_files), batch_size):
            batch = pdf_files[i:i+batch_size]
            print(f"Processing batch {i//batch_size + 1}/{(len(pdf_files)-1)//batch_size + 1}")

            for pdf_name in batch:
                print(f"Processing {pdf_name}")
                chunks = self.process_pdf(pdf_name)
                all_chunks.extend(chunks)
                print(f"Extracted {len(chunks)} chunks from {pdf_name}")

            # Clear memory after each batch
            clear_memory()

        return all_chunks

# === VECTOR DATABASE SETUP ===
class VectorDBManager:
    def __init__(self, model_name: str = "sentence-transformers/all-MiniLM-L6-v2"):
        """Initialize vector database manager

        Args:
            model_name: Name of the embedding model
        """
        # Initialize embedding model with normalization
        try:
            self.embedding_model = HuggingFaceEmbeddings(
                model_name=model_name,
                model_kwargs={"device": "cpu"},
                encode_kwargs={"normalize_embeddings": True}
            )
        except Exception as e:
            print(f"Error initializing embedding model {model_name}: {str(e)}")
            print("Falling back to all-MiniLM-L6-v2 model")
            self.embedding_model = HuggingFaceEmbeddings(
                model_name="sentence-transformers/all-MiniLM-L6-v2",
                model_kwargs={"device": "cpu"},
                encode_kwargs={"normalize_embeddings": True}
            )

        # Initialize cross-encoder for re-ranking
        try:
            self.cross_encoder = CrossEncoder('cross-encoder/ms-marco-MiniLM-L-6-v2')
        except Exception as e:
            print(f"Error initializing cross-encoder: {str(e)}")
            self.cross_encoder = None

        self.vectordb = None
        # BM25 index for hybrid search
        self.bm25_index = None
        self.chunks = []
        self.tokenized_chunks = []

    def _prepare_bm25(self, chunks: List[PDFChunk]):
        """Prepare BM25 index for hybrid search"""
        # Tokenize chunks for BM25
        try:
            tokenized_chunks = []
            for chunk in chunks:
                # Tokenize and remove stopwords
                tokens = word_tokenize(chunk.text.lower())
                stop_words = set(stopwords.words('english'))
                filtered_tokens = [w for w in tokens if w.isalnum() and w not in stop_words]
                tokenized_chunks.append(filtered_tokens)

            # Create BM25 index
            self.bm25_index = BM25Okapi(tokenized_chunks)
            self.tokenized_chunks = tokenized_chunks
        except Exception as e:
            print(f"Error creating BM25 index: {str(e)}")
            print(traceback.format_exc())
            self.bm25_index = None

    def create_vector_db(self, chunks: List[PDFChunk]) -> None:
        """Create vector database from text chunks

        Args:
            chunks: List of PDFChunk objects
        """
        try:
            if not chunks or len(chunks) == 0:
                print("ERROR: No chunks provided to create vector database")
                return

            print(f"Creating vector DB with {len(chunks)} chunks")

            # Store chunks for hybrid search
            self.chunks = chunks

            # Prepare data for vector DB
            chunk_texts = [chunk.text for chunk in chunks]

            # Create BM25 index for hybrid search
            print("Creating BM25 index for hybrid search")
            self._prepare_bm25(chunks)

            # Process in smaller batches to manage memory
            batch_size = 32
            all_embeddings = []

            for i in range(0, len(chunk_texts), batch_size):
                batch = chunk_texts[i:i+batch_size]
                print(f"Embedding batch {i//batch_size + 1}/{(len(chunk_texts)-1)//batch_size + 1}")

                # Generate embeddings for the batch
                batch_embeddings = self.embedding_model.embed_documents(batch)
                all_embeddings.extend(batch_embeddings)

                # Clear memory after each batch
                clear_memory()

            # Create FAISS index
            print(f"Creating FAISS index with {len(all_embeddings)} embeddings")
            self.vectordb = FAISS.from_embeddings(
                text_embeddings=list(zip(chunk_texts, all_embeddings)),
                embedding=self.embedding_model
            )

            print(f"Vector database created with {len(chunks)} documents")

        except Exception as e:
            print(f"Error creating vector database: {str(e)}")
            print(traceback.format_exc())
            raise

    def _format_chunk_with_metadata(self, chunk: PDFChunk) -> str:
        """Format a chunk with its metadata for better context"""
        return f"Source: {chunk.source} | Page: {chunk.page_num}\n\n{chunk.text}"

    def _rerank_with_cross_encoder(self, query: str, chunks: List[PDFChunk], k: int = 5) -> List[PDFChunk]:
        """Re-rank chunks using cross-encoder

        Args:
            query: User query
            chunks: List of retrieved chunks
            k: Number of top chunks to return

        Returns:
            Re-ranked chunks
        """
        if not self.cross_encoder or not chunks:
            return chunks[:k] if len(chunks) > k else chunks

        try:
            # Prepare passage pairs for re-ranking
            pairs = [[query, chunk.text] for chunk in chunks]

            # Score passages in smaller batches to prevent OOM
            batch_size = 16
            all_scores = []

            for i in range(0, len(pairs), batch_size):
                batch_pairs = pairs[i:i+batch_size]
                batch_scores = self.cross_encoder.predict(batch_pairs)
                all_scores.extend(batch_scores)

                # Clear memory
                clear_memory()

            # Create chunk-score pairs
            scored_chunks = list(zip(chunks, all_scores))

            # Sort by score
            scored_chunks.sort(key=lambda x: x[1], reverse=True)

            # Return top k chunks
            return [chunk for chunk, score in scored_chunks[:k]]
        except Exception as e:
            print(f"Error during cross-encoder re-ranking: {str(e)}")
            # Fallback to original chunks
            return chunks[:k] if len(chunks) > k else chunks

    def hybrid_search(self, query: str, k: int = 5, alpha: float = 0.7) -> List[str]:
        """Hybrid search combining vector search and BM25 with cross-encoder re-ranking

        Args:
            query: Query text
            k: Number of results to return
            alpha: Weight for vector search (1-alpha for BM25)

        Returns:
            List of formatted documents
        """
        if self.vectordb is None:
            print("Vector database not initialized")
            return []

        try:
            # Get vector search results
            vector_results = self.vectordb.similarity_search(query, k=k*3)  # Get more for re-ranking
            vector_texts = [doc.page_content for doc in vector_results]

            retrieved_chunks = []

            # Combine with BM25 if available
            if self.bm25_index is not None:
                try:
                    # Tokenize query for BM25
                    query_tokens = word_tokenize(query.lower())
                    stop_words = set(stopwords.words('english'))
                    filtered_query = [w for w in query_tokens if w.isalnum() and w not in stop_words]

                    # Get BM25 scores
                    bm25_scores = self.bm25_index.get_scores(filtered_query)

                    # Combine scores (normalized)
                    combined_results = []
                    seen_texts = set()

                    # First add vector results with their positions as scores
                    for i, text in enumerate(vector_texts):
                        if text not in seen_texts:
                            seen_texts.add(text)
                            # Find corresponding chunk
                            for j, chunk in enumerate(self.chunks):
                                if chunk.text == text:
                                    # Combine scores: alpha * vector_score + (1-alpha) * bm25_score
                                    # For vector, use inverse of position as score (normalized)
                                    vector_score = 1.0 - (i / len(vector_texts))
                                    # Normalize BM25 score
                                    bm25_score = bm25_scores[j] / max(bm25_scores) if max(bm25_scores) > 0 else 0
                                    combined_score = alpha * vector_score + (1-alpha) * bm25_score

                                    combined_results.append((chunk, combined_score))
                                    break

                    # Sort by combined score
                    combined_results.sort(key=lambda x: x[1], reverse=True)

                    # Get top k*2 results for re-ranking
                    retrieved_chunks = [item[0] for item in combined_results[:k*2]]
                except Exception as e:
                    print(f"Error in BM25 scoring: {str(e)}")
                    # Fallback to vector search results
                    retrieved_chunks = [self.chunks[i] for i, text in enumerate(self.chunks)
                                        if text.text in vector_texts[:k*2]]
            else:
                # Just use vector search results if BM25 is not available
                retrieved_chunks = [self.chunks[i] for i, chunk in enumerate(self.chunks)
                                     if chunk.text in vector_texts[:k*2]]

            # Re-rank with cross-encoder
            if retrieved_chunks:
                reranked_chunks = self._rerank_with_cross_encoder(query, retrieved_chunks, k)
                # Format results with metadata
                final_results = [self._format_chunk_with_metadata(chunk) for chunk in reranked_chunks]
            else:
                # Fallback to basic results
                final_results = vector_texts[:k]

            return final_results
        except Exception as e:
            print(f"Error during hybrid search: {str(e)}")
            return []

# === QUERY EXPANSION ===
class QueryExpander:
    def __init__(self, llm_model):
        """Initialize query expander

        Args:
            llm_model: LLM model for query expansion
        """
        self.llm = llm_model

    def expand_query(self, query: str) -> str:
        """Expand the query using the LLM to improve retrieval

        Args:
            query: Original query

        Returns:
            Expanded query
        """
        try:
            prompt = f"""<s>[INST] I need to search for documents related to this question: "{query}"

Please help me expand this query by identifying key concepts, synonyms, and related terms that might be used in the documents.
Return only the expanded search query, without any explanations or additional text. [/INST]"""

            expanded = self.llm.generate(prompt, max_tokens=100, temperature=0.3)

            # Combine original and expanded
            combined = f"{query} {expanded}"

            # Limit length
            if len(combined) > 300:
                combined = combined[:300]

            return combined
        except:
            # Return original query if expansion fails
            return query

# === LLM SETUP ===
class MistralModel:
    def __init__(self, model_path: str = "models/mistral-7b-instruct-v0.3.Q8_0.gguf"):
        """Initialize Mistral model

        Args:
            model_path: Path to the model file
        """
        try:
            # Initialize Mistral with llama.cpp
            self.llm = Llama(
                model_path=model_path,
                n_ctx=4096,         # Increased context window for better reasoning
                n_batch=256,        # Batch size to save memory
                n_gpu_layers=0,     # Run on CPU only for Colab free tier
                verbose=False
            )
        except Exception as e:
            print(f"Error initializing Mistral model: {str(e)}")
            raise

    def generate(self, prompt: str,
                 max_tokens: int = 512,
                 temperature: float = 0.7,
                 top_p: float = 0.9,
                 stream: bool = False) -> Union[str, Generator[str, None, None]]:
        """Generate text using Mistral

        Args:
            prompt: Input prompt
            max_tokens: Maximum number of tokens to generate
            temperature: Sampling temperature
            top_p: Top-p sampling parameter
            stream: Whether to stream the output

        Returns:
            Generated text or generator if streaming
        """
        try:
            if stream:
                return self._generate_stream(prompt, max_tokens, temperature, top_p)
            else:
                output = self.llm(
                    prompt,
                    max_tokens=max_tokens,
                    temperature=temperature,
                    top_p=top_p,
                    echo=False
                )
                return output["choices"][0]["text"].strip()
        except Exception as e:
            print(f"Error generating text: {str(e)}")
            return "Error: Could not generate response."

    def _generate_stream(self, prompt: str,
                         max_tokens: int = 512,
                         temperature: float = 0.7,
                         top_p: float = 0.9) -> Generator[str, None, None]:
        """Stream text generation using Mistral

        Args:
            prompt: Input prompt
            max_tokens: Maximum number of tokens to generate
            temperature: Sampling temperature
            top_p: Top-p sampling parameter

        Yields:
            Generated text tokens
        """
        response = ""
        for output in self.llm(
            prompt,
            max_tokens=max_tokens,
            temperature=temperature,
            top_p=top_p,
            echo=False,
            stream=True
        ):
            token = output["choices"][0]["text"]
            response += token
            yield response

# === SELF-CHECKING ===
class SelfChecker:
    def __init__(self, llm_model):
        """Initialize self-checker for improved response quality

        Args:
            llm_model: LLM model to use for checking
        """
        self.llm = llm_model

    def check_answer(self, query: str, initial_answer: str, contexts: List[str]) -> str:
        """Check if answer is correct and complete based on the contexts

        Args:
            query: User query
            initial_answer: Initial generated answer
            contexts: Retrieved contexts used to generate the answer

        Returns:
            Improved answer after reflection
        """
        # Guard against very long inputs that could cause runtime disconnection
        # Limit contexts to prevent excessive token usage
        max_contexts_len = 4000
        contexts_text = "\n\n".join(contexts)
        if len(contexts_text) > max_contexts_len:
            # Truncate while keeping as many complete contexts as possible
            truncated_contexts = []
            current_len = 0
            for ctx in contexts:
                if current_len + len(ctx) + 2 <= max_contexts_len:
                    truncated_contexts.append(ctx)
                    current_len += len(ctx) + 2
                else:
                    break
            contexts_text = "\n\n".join(truncated_contexts)

        # Check if we should skip reflection to prevent disconnection
        if len(initial_answer) + len(contexts_text) + len(query) > 6000:
            print("Skipping reflection due to excessive input length")
            return initial_answer

        try:
            prompt = f"""<s>[INST] You're an AI assistant tasked with evaluating and improving an answer to a user query.

QUERY: {query}

INITIAL ANSWER: {initial_answer}

AVAILABLE CONTEXTS:
{contexts_text}

First, carefully check if the initial answer:
1. Is factually accurate based on the provided contexts
2. Addresses all aspects of the user's query
3. Contains any information not supported by the contexts
4. Misses important information from the contexts

Then improve the answer to fix any issues identified. The final answer should:
- Be comprehensive and accurate based ONLY on the contexts
- Not include any unsupported information
- Be well-structured and clear
- Cite specific sources when appropriate (e.g., "According to [Source, Page X]...")

Provide ONLY the improved answer without explanations about your reasoning process. [/INST]"""

            # We use slightly lower temperature for more focused reflection
            improved_answer = self.llm.generate(
                prompt,
                max_tokens=1024,
                temperature=0.3,
                stream=False
            )

            # If reflection produced nothing useful, return original answer
            if not improved_answer or len(improved_answer) < 10:
                return initial_answer

            return improved_answer

        except Exception as e:
            # On any error, return the original answer to ensure robustness
            print(f"Self-check error: {str(e)}")
            return initial_answer

# === RAG SYSTEM ===
class RAGSystem:
    def __init__(self, pdf_processor: PDFProcessor,
                 vector_db: VectorDBManager,
                 model: MistralModel):
        """Initialize RAG system

        Args:
            pdf_processor: PDF processor instance
            vector_db: Vector database manager instance
            model: LLM model instance
        """
        self.pdf_processor = pdf_processor
        self.vector_db = vector_db
        self.model = model
        self.query_expander = QueryExpander(model)
        self.self_checker = SelfChecker(model)
        self.is_initialized = False

    def process_documents(self) -> bool:
        """Process all documents and create vector database

        Returns:
            True if successful, False otherwise
        """
        try:
            # Process PDFs
            chunks = self.pdf_processor.process_all_pdfs()
            if not chunks:
                print("No chunks were extracted from PDFs")
                return False

            print(f"Total chunks extracted: {len(chunks)}")

            # Create vector database
            print("Creating vector database...")
            self.vector_db.create_vector_db(chunks)

            # Verify success
            if self.vector_db.vectordb is None:
                print("Failed to create vector database")
                return False

            # Set initialization flag
            self.is_initialized = True
            return True

        except Exception as e:
            print(f"Error processing documents: {str(e)}")
            print(traceback.format_exc())
            return False

    def generate_prompt(self, query: str, contexts: List[str]) -> str:
        """Generate prompt for the LLM with better instructions

        Args:
            query: User query
            contexts: Retrieved contexts

        Returns:
            Formatted prompt
        """
        # Format contexts with numbering for better reference
        formatted_contexts = ""
        for i, context in enumerate(contexts):
            formatted_contexts += f"[CONTEXT {i+1}]\n{context}\n\n"

        # Create prompt with Mistral's chat format
        prompt = f"""<s>[INST] You are an AI assistant that answers questions based on the provided context information.

User Query: {query}

Below are relevant passages from documents that might help answer the query:

{formatted_contexts}

Using ONLY the information provided in the context above, provide a comprehensive answer to the user's query.
If the provided context doesn't contain relevant information to answer the query, clearly state: "I don't have enough information in the provided context to answer this question."

Do not use any prior knowledge that is not contained in the provided context.
If quoting from the context, mention the source document and page number.
Organize your answer in a clear, coherent manner. [/INST]"""
        return prompt

    def answer_query(self, query: str, k: int = 5, max_tokens: int = 512,
                 temperature: float = 0.7, stream: bool = False, enable_reflection: bool = True) -> Union[str, Generator[str, None, None]]:
        """Answer a query using RAG with query expansion and self-checking

        Args:
            query: User query
            k: Number of contexts to retrieve
            max_tokens: Maximum number of tokens to generate
            temperature: Temperature for generation
            stream: Whether to stream the output
            enable_reflection: Whether to enable self-reflection for better answers

        Returns:
            Answer text or generator if streaming
        """
        # Check if system is initialized
        if not self.is_initialized or self.vector_db.vectordb is None:
            return "Error: Documents have not been processed yet. Please process documents first."

        try:
            # Expand query for better retrieval
            expanded_query = self.query_expander.expand_query(query)
            print(f"Expanded query: {expanded_query}")

            # Retrieve relevant contexts using hybrid search
            contexts = self.vector_db.hybrid_search(expanded_query, k=k)

            if not contexts:
                return "No relevant information found in the documents. Please try a different query or check if documents were processed correctly."

            # Generate prompt with improved instructions
            prompt = self.generate_prompt(query, contexts)

            # For streaming, we can't do self-checking
            if stream:
                return self.model.generate(
                    prompt,
                    max_tokens=max_tokens,
                    temperature=temperature,
                    stream=True
                )

            # Generate initial answer
            initial_answer = self.model.generate(
                prompt,
                max_tokens=max_tokens,
                temperature=temperature,
                stream=False
            )

            # Perform self-checking if enabled and initial answer exists
            if enable_reflection and initial_answer and len(initial_answer) > 10:
                try:
                    print("Performing self-checking to improve answer quality...")
                    improved_answer = self.self_checker.check_answer(query, initial_answer, contexts)
                    return improved_answer
                except Exception as e:
                    print(f"Error during self-checking: {str(e)}")
                    # Fallback to initial answer if self-checking fails
                    return initial_answer
            else:
                return initial_answer

        except Exception as e:
            print(f"Error answering query: {str(e)}")
            print(traceback.format_exc())
            return f"Error processing your query: {str(e)}"

# === GRADIO UI ===
class RAGUI:
    def __init__(self, rag_system: RAGSystem):
        """Initialize RAG UI

        Args:
            rag_system: RAG system instance
        """
        self.rag_system = rag_system
        self.pdf_dir = rag_system.pdf_processor.pdf_dir
        self.interface = None

    def _list_uploaded_pdfs(self) -> str:
        """List all uploaded PDFs"""
        pdfs = self.rag_system.pdf_processor.list_pdfs()
        if not pdfs:
            return "No PDFs uploaded yet."
        return "\n".join([f"- {pdf}" for pdf in pdfs])

    def upload_pdf(self, files) -> str:
        """Upload PDF files

        Args:
            files: File objects

        Returns:
            Status message
        """
        try:
            # Create directory if it doesn't exist
            os.makedirs(self.pdf_dir, exist_ok=True)

            # Copy files to pdf directory
            for file in files:
                shutil.copy(file.name, os.path.join(self.pdf_dir, os.path.basename(file.name)))

            return f"Successfully uploaded {len(files)} file(s). Please process documents to make them searchable."
        except Exception as e:
            return f"Error uploading files: {str(e)}"

    def process_documents(self) -> str:
        """Process documents and create vector database

        Returns:
            Status message
        """
        try:
            # Check if there are PDFs
            pdf_files = self.rag_system.pdf_processor.list_pdfs()
            if not pdf_files:
                return "No PDF files uploaded. Please upload PDFs first."

            # Process PDFs
            start_time = time.time()
            success = self.rag_system.process_documents()
            process_time = time.time() - start_time

            if success:
                return f"Successfully processed {len(pdf_files)} PDF file(s) in {process_time:.2f} seconds. You can now ask questions."
            else:
                return "Failed to process documents. Check the logs for details."
        except Exception as e:
            return f"Error processing documents: {str(e)}"

    def answer_query(self, query: str, stream_output: bool = True,
                    k: int = 4, temperature: float = 0.7,
                    enable_reflection: bool = True) -> str:
        """Answer a query using RAG

        Args:
            query: User query
            stream_output: Whether to stream the output
            k: Number of contexts to retrieve
            temperature: Temperature for text generation
            enable_reflection: Whether to use reflection to improve answers

        Returns:
            Answer text
        """
        if not query or query.strip() == "":
            return "Please enter a query."

        # Check if system is initialized
        if not self.rag_system.is_initialized:
            return "Documents have not been processed yet. Please process documents first."

        try:
            # For streaming, we need to handle gradio uniqueness
            if stream_output:
                # We can't stream with reflection
                return self.rag_system.answer_query(
                    query,
                    k=k,
                    max_tokens=1024,
                    temperature=temperature,
                    stream=True,
                    enable_reflection=False
                )
            else:
                return self.rag_system.answer_query(
                    query,
                    k=k,
                    max_tokens=1024,
                    temperature=temperature,
                    stream=False,
                    enable_reflection=enable_reflection
                )
        except Exception as e:
            print(f"Error in answer_query: {str(e)}")
            print(traceback.format_exc())
            return f"Error processing your query: {str(e)}"

    def launch(self):
        """Launch Gradio UI"""
        try:
            with gr.Blocks(title="Document Q&A System") as self.interface:
                gr.Markdown("# PDF Question Answering System")
                gr.Markdown("Upload PDF documents and ask questions about their content.")

                with gr.Tab("Upload & Process"):
                    with gr.Row():
                        with gr.Column():
                            upload_button = gr.File(
                                label="Upload PDF Files",
                                file_count="multiple",
                                file_types=[".pdf"]
                            )
                            upload_output = gr.Textbox(
                                label="Upload Status",
                                interactive=False
                            )
                            upload_btn = gr.Button("Upload Files")

                        with gr.Column():
                            pdf_list = gr.Textbox(
                                label="Uploaded PDFs",
                                value=self._list_uploaded_pdfs(),
                                interactive=False
                            )
                            refresh_btn = gr.Button("Refresh List")

                    process_btn = gr.Button("Process Documents")
                    process_output = gr.Textbox(
                        label="Processing Status",
                        interactive=False
                    )

                with gr.Tab("Ask Questions"):
                    with gr.Row():
                        with gr.Column():
                            query_input = gr.Textbox(
                                label="Enter your question",
                                placeholder="What are the main findings of the report?",
                                lines=2
                            )

                            with gr.Row():
                                k_slider = gr.Slider(
                                    minimum=1,
                                    maximum=10,
                                    value=4,
                                    step=1,
                                    label="Number of contexts to retrieve"
                                )
                                temp_slider = gr.Slider(
                                    minimum=0.1,
                                    maximum=1.0,
                                    value=0.7,
                                    step=0.1,
                                    label="Temperature"
                                )

                            with gr.Row():
                                stream_checkbox = gr.Checkbox(
                                    label="Stream output",
                                    value=True
                                )
                                reflection_checkbox = gr.Checkbox(
                                    label="Use self-reflection (disables streaming)",
                                    value=True
                                )

                            query_btn = gr.Button("Submit Question")

                    answer_output = gr.Textbox(
                        label="Answer",
                        interactive=False,
                        lines=15
                    )

                # Event handlers
                upload_btn.click(
                    fn=self.upload_pdf,
                    inputs=[upload_button],
                    outputs=[upload_output]
                )

                refresh_btn.click(
                    fn=lambda: self._list_uploaded_pdfs(),
                    inputs=[],
                    outputs=[pdf_list]
                )

                process_btn.click(
                    fn=self.process_documents,
                    inputs=[],
                    outputs=[process_output]
                )

                query_btn.click(
                    fn=self.answer_query,
                    inputs=[query_input, stream_checkbox, k_slider, temp_slider, reflection_checkbox],
                    outputs=[answer_output]
                )

                # Checkbox dependency
                def update_stream_state(reflection_enabled):
                    return not reflection_enabled if reflection_enabled else gr.update()

                reflection_checkbox.change(
                    fn=update_stream_state,
                    inputs=[reflection_checkbox],
                    outputs=[stream_checkbox]
                )

            # Launch UI
            self.interface.launch(share=True)

        except Exception as e:
            print(f"Error launching UI: {str(e)}")
            print(traceback.format_exc())

# === MAIN APPLICATION ===
def main():
    # Initialize components
    print("Initializing PDF processor...")
    pdf_processor = PDFProcessor()

    print("Initializing vector database manager...")
    vector_db = VectorDBManager()

    print("Initializing Mistral model...")
    model = MistralModel()

    print("Initializing RAG system...")
    rag_system = RAGSystem(pdf_processor, vector_db, model)

    print("Initializing UI...")
    ui = RAGUI(rag_system)

    print("Launching UI...")
    ui.launch()

if __name__ == "__main__":
    main()