chat.py

"""
DOLPHIN PDF Document AI - Final Version
Optimized for HuggingFace Spaces NVIDIA T4 Small deployment
"""

import gradio as gr
import json
import markdown
import cv2
import numpy as np
from PIL import Image
from transformers import AutoProcessor, VisionEncoderDecoderModel, Gemma3nForConditionalGeneration, pipeline
import torch
try:
    from sentence_transformers import SentenceTransformer
    import numpy as np
    from sklearn.metrics.pairwise import cosine_similarity
    import google.generativeai as genai
    RAG_DEPENDENCIES_AVAILABLE = True
except ImportError as e:
    print(f"RAG dependencies not available: {e}")
    print("Please install: pip install sentence-transformers scikit-learn google-generativeai")
    RAG_DEPENDENCIES_AVAILABLE = False
    SentenceTransformer = None
import os
import tempfile
import uuid
import base64
import io
from utils.utils import *
from utils.markdown_utils import MarkdownConverter

# Math extension is optional for enhanced math rendering
MATH_EXTENSION_AVAILABLE = False
try:
    from mdx_math import MathExtension
    MATH_EXTENSION_AVAILABLE = True
except ImportError:
    pass


class DOLPHIN:
    def __init__(self, model_id_or_path):
        """Initialize the Hugging Face model optimized for T4 Small"""
        self.processor = AutoProcessor.from_pretrained(model_id_or_path)
        self.model = VisionEncoderDecoderModel.from_pretrained(
            model_id_or_path,
            torch_dtype=torch.float16,
            device_map="auto" if torch.cuda.is_available() else None
        )
        self.model.eval()
        
        self.device = "cuda" if torch.cuda.is_available() else "cpu"
        if not torch.cuda.is_available():
            self.model = self.model.float()
        
        self.tokenizer = self.processor.tokenizer
        
    def chat(self, prompt, image):
        """Process an image or batch of images with the given prompt(s)"""
        is_batch = isinstance(image, list)
        
        if not is_batch:
            images = [image]
            prompts = [prompt]
        else:
            images = image
            prompts = prompt if isinstance(prompt, list) else [prompt] * len(images)
        
        batch_inputs = self.processor(images, return_tensors="pt", padding=True)
        batch_pixel_values = batch_inputs.pixel_values
        
        if torch.cuda.is_available():
            batch_pixel_values = batch_pixel_values.half().to(self.device)
        else:
            batch_pixel_values = batch_pixel_values.to(self.device)
        
        prompts = [f"<s>{p} <Answer/>" for p in prompts]
        batch_prompt_inputs = self.tokenizer(
            prompts,
            add_special_tokens=False,
            return_tensors="pt"
        )

        batch_prompt_ids = batch_prompt_inputs.input_ids.to(self.device)
        batch_attention_mask = batch_prompt_inputs.attention_mask.to(self.device)
        
        with torch.no_grad():
            outputs = self.model.generate(
                pixel_values=batch_pixel_values,
                decoder_input_ids=batch_prompt_ids,
                decoder_attention_mask=batch_attention_mask,
                min_length=1,
                max_length=1024,  # Reduced for T4 Small
                pad_token_id=self.tokenizer.pad_token_id,
                eos_token_id=self.tokenizer.eos_token_id,
                use_cache=True,
                bad_words_ids=[[self.tokenizer.unk_token_id]],
                return_dict_in_generate=True,
                do_sample=False,
                num_beams=1,
                repetition_penalty=1.1,
                temperature=1.0
            )
        
        sequences = self.tokenizer.batch_decode(outputs.sequences, skip_special_tokens=False)
        
        results = []
        for i, sequence in enumerate(sequences):
            cleaned = sequence.replace(prompts[i], "").replace("<pad>", "").replace("</s>", "").strip()
            results.append(cleaned)
            
        if not is_batch:
            return results[0]
        return results


def convert_pdf_to_images_gradio(pdf_file):
    """Convert uploaded PDF file to list of PIL Images"""
    try:
        import pymupdf
        
        if isinstance(pdf_file, str):
            pdf_document = pymupdf.open(pdf_file)
        else:
            pdf_bytes = pdf_file.read()
            pdf_document = pymupdf.open(stream=pdf_bytes, filetype="pdf")
        
        images = []
        for page_num in range(len(pdf_document)):
            page = pdf_document[page_num]
            mat = pymupdf.Matrix(2.0, 2.0)
            pix = page.get_pixmap(matrix=mat)
            img_data = pix.tobytes("png")
            pil_image = Image.open(io.BytesIO(img_data)).convert("RGB")
            images.append(pil_image)
        
        pdf_document.close()
        return images
        
    except Exception as e:
        raise Exception(f"Error converting PDF: {str(e)}")


def process_pdf_document(pdf_file, model, progress=gr.Progress()):
    """Process uploaded PDF file page by page"""
    if pdf_file is None:
        return "No PDF file uploaded", ""
    
    try:
        progress(0.1, desc="Converting PDF to images...")
        images = convert_pdf_to_images_gradio(pdf_file)
        
        if not images:
            return "Failed to convert PDF to images", ""
        
        all_results = []
        
        for page_idx, pil_image in enumerate(images):
            progress((page_idx + 1) / len(images) * 0.8 + 0.1, 
                    desc=f"Processing page {page_idx + 1}/{len(images)}...")
            
            layout_output = model.chat("Parse the reading order of this document.", pil_image)
            
            padded_image, dims = prepare_image(pil_image)
            recognition_results = process_elements_optimized(
                layout_output, 
                padded_image, 
                dims, 
                model, 
                max_batch_size=2  # Smaller batch for T4 Small
            )
            
            try:
                markdown_converter = MarkdownConverter()
                markdown_content = markdown_converter.convert(recognition_results)
            except:
                markdown_content = generate_fallback_markdown(recognition_results)
            
            page_result = {
                "page_number": page_idx + 1,
                "markdown": markdown_content
            }
            all_results.append(page_result)
        
        progress(1.0, desc="Processing complete!")
        
        combined_markdown = "\n\n---\n\n".join([
            f"# Page {result['page_number']}\n\n{result['markdown']}" 
            for result in all_results
        ])
        
        return combined_markdown, "processing_complete"
        
    except Exception as e:
        error_msg = f"Error processing PDF: {str(e)}"
        return error_msg, "error"


def process_elements_optimized(layout_results, padded_image, dims, model, max_batch_size=2):
    """Optimized element processing for T4 Small"""
    layout_results = parse_layout_string(layout_results)
    
    text_elements = []
    table_elements = []
    figure_results = []
    previous_box = None
    reading_order = 0
    
    for bbox, label in layout_results:
        try:
            x1, y1, x2, y2, orig_x1, orig_y1, orig_x2, orig_y2, previous_box = process_coordinates(
                bbox, padded_image, dims, previous_box
            )
            
            cropped = padded_image[y1:y2, x1:x2]
            if cropped.size > 0 and cropped.shape[0] > 3 and cropped.shape[1] > 3:
                if label == "fig":
                    pil_crop = Image.fromarray(cv2.cvtColor(cropped, cv2.COLOR_BGR2RGB))
                    pil_crop = crop_margin(pil_crop)
                    
                    buffered = io.BytesIO()
                    pil_crop.save(buffered, format="PNG")
                    img_base64 = base64.b64encode(buffered.getvalue()).decode()
                    data_uri = f"data:image/png;base64,{img_base64}"
                    
                    figure_results.append({
                        "label": label,
                        "text": f"![Figure {reading_order}]({data_uri})",
                        "bbox": [orig_x1, orig_y1, orig_x2, orig_y2],
                        "reading_order": reading_order,
                    })
                else:
                    pil_crop = Image.fromarray(cv2.cvtColor(cropped, cv2.COLOR_BGR2RGB))
                    element_info = {
                        "crop": pil_crop,
                        "label": label,
                        "bbox": [orig_x1, orig_y1, orig_x2, orig_y2],
                        "reading_order": reading_order,
                    }
                    
                    if label == "tab":
                        table_elements.append(element_info)
                    else:
                        text_elements.append(element_info)
                        
            reading_order += 1
            
        except Exception as e:
            print(f"Error processing element {label}: {str(e)}")
            continue
    
    recognition_results = figure_results.copy()
    
    if text_elements:
        text_results = process_element_batch_optimized(
            text_elements, model, "Read text in the image.", max_batch_size
        )
        recognition_results.extend(text_results)
    
    if table_elements:
        table_results = process_element_batch_optimized(
            table_elements, model, "Parse the table in the image.", max_batch_size
        )
        recognition_results.extend(table_results)
    
    recognition_results.sort(key=lambda x: x.get("reading_order", 0))
    return recognition_results


def process_element_batch_optimized(elements, model, prompt, max_batch_size=2):
    """Process elements in small batches for T4 Small"""
    results = []
    batch_size = min(len(elements), max_batch_size)
    
    for i in range(0, len(elements), batch_size):
        batch_elements = elements[i:i+batch_size]
        crops_list = [elem["crop"] for elem in batch_elements]
        prompts_list = [prompt] * len(crops_list)
        
        batch_results = model.chat(prompts_list, crops_list)
        
        for j, result in enumerate(batch_results):
            elem = batch_elements[j]
            results.append({
                "label": elem["label"],
                "bbox": elem["bbox"],
                "text": result.strip(),
                "reading_order": elem["reading_order"],
            })
            
        del crops_list, batch_elements
        if torch.cuda.is_available():
            torch.cuda.empty_cache()
    
    return results


def generate_fallback_markdown(recognition_results):
    """Generate basic markdown if converter fails"""
    markdown_content = ""
    for element in recognition_results:
        if element["label"] == "tab":
            markdown_content += f"\n\n{element['text']}\n\n"
        elif element["label"] in ["para", "title", "sec", "sub_sec"]:
            markdown_content += f"{element['text']}\n\n"
        elif element["label"] == "fig":
            markdown_content += f"{element['text']}\n\n"
    return markdown_content


# Initialize model
model_path = "./hf_model"
if not os.path.exists(model_path):
    model_path = "ByteDance/DOLPHIN"

# Model paths and configuration
model_path = "./hf_model" if os.path.exists("./hf_model") else "ByteDance/DOLPHIN"
hf_token = os.getenv('HF_TOKEN')

# Don't load models initially - load them on demand
model_status = "✅ Models ready (Dynamic loading)"

# Initialize embedding model and Gemini API
if RAG_DEPENDENCIES_AVAILABLE:
    try:
        print("Loading embedding model for RAG...")
        embedding_model = SentenceTransformer('all-MiniLM-L6-v2', device='cpu')
        print("✅ Embedding model loaded successfully (CPU)")
        
        # Initialize Gemini API
        gemini_api_key = os.getenv('GEMINI_API_KEY')
        if gemini_api_key:
            genai.configure(api_key=gemini_api_key)
            gemini_model = genai.GenerativeModel('gemma-3n-e4b-it')
            print("✅ Gemini API configured successfully")
        else:
            print("❌ GEMINI_API_KEY not found in environment")
            gemini_model = None
    except Exception as e:
        print(f"❌ Error loading models: {e}")
        import traceback
        traceback.print_exc()
        embedding_model = None
        gemini_model = None
else:
    print("❌ RAG dependencies not available")
    embedding_model = None
    gemini_model = None

# Model management functions
def load_dolphin_model():
    """Load DOLPHIN model for PDF processing"""
    global dolphin_model, current_model
    
    if current_model == "dolphin":
        return dolphin_model
    
    # No need to unload chatbot model (using API now)
    
    try:
        print("Loading DOLPHIN model...")
        dolphin_model = DOLPHIN(model_path)
        current_model = "dolphin"
        print(f"✅ DOLPHIN model loaded (Device: {dolphin_model.device})")
        return dolphin_model
    except Exception as e:
        print(f"❌ Error loading DOLPHIN model: {e}")
        return None

def unload_dolphin_model():
    """Unload DOLPHIN model to free memory"""
    global dolphin_model, current_model
    
    if dolphin_model is not None:
        print("Unloading DOLPHIN model...")
        del dolphin_model
        dolphin_model = None
        if current_model == "dolphin":
            current_model = None
        if torch.cuda.is_available():
            torch.cuda.empty_cache()
        print("✅ DOLPHIN model unloaded")

def initialize_gemini_model():
    """Initialize Gemini API model"""
    global gemini_model
    
    if gemini_model is not None:
        return gemini_model
    
    try:
        gemini_api_key = os.getenv('GEMINI_API_KEY')
        if not gemini_api_key:
            print("❌ GEMINI_API_KEY not found in environment")
            return None
        
        print("Initializing Gemini API...")
        genai.configure(api_key=gemini_api_key)
        gemini_model = genai.GenerativeModel('gemma-3n-e4b-it')
        print("✅ Gemini API model ready")
        return gemini_model
    except Exception as e:
        print(f"❌ Error initializing Gemini model: {e}")
        import traceback
        traceback.print_exc()
        return None


# Global state for managing tabs
processed_markdown = ""
show_results_tab = False
document_chunks = []
document_embeddings = None

# Global model state
dolphin_model = None
gemini_model = None
current_model = None  # Track which model is currently loaded


def chunk_document(text, chunk_size=300, overlap=50):
    """Split document into overlapping chunks for RAG - optimized for API quota"""
    words = text.split()
    chunks = []
    
    for i in range(0, len(words), chunk_size - overlap):
        chunk = ' '.join(words[i:i + chunk_size])
        if chunk.strip():
            chunks.append(chunk)
    
    return chunks

def create_embeddings(chunks):
    """Create embeddings for document chunks"""
    if embedding_model is None:
        return None
    
    try:
        # Process in smaller batches on CPU
        batch_size = 32
        embeddings = []
        
        for i in range(0, len(chunks), batch_size):
            batch = chunks[i:i + batch_size]
            batch_embeddings = embedding_model.encode(batch, show_progress_bar=False)
            embeddings.extend(batch_embeddings)
        
        return np.array(embeddings)
    except Exception as e:
        print(f"Error creating embeddings: {e}")
        return None

def retrieve_relevant_chunks(question, chunks, embeddings, top_k=3):
    """Retrieve most relevant chunks for a question"""
    if embedding_model is None or embeddings is None:
        return chunks[:3]  # Fallback to first 3 chunks
    
    try:
        question_embedding = embedding_model.encode([question], show_progress_bar=False)
        similarities = cosine_similarity(question_embedding, embeddings)[0]
        
        # Get top-k most similar chunks
        top_indices = np.argsort(similarities)[-top_k:][::-1]
        relevant_chunks = [chunks[i] for i in top_indices]
        
        return relevant_chunks
    except Exception as e:
        print(f"Error retrieving chunks: {e}")
        return chunks[:3]  # Fallback

def process_uploaded_pdf(pdf_file, progress=gr.Progress()):
    """Main processing function for uploaded PDF"""
    global processed_markdown, show_results_tab, document_chunks, document_embeddings
    
    if pdf_file is None:
        return "❌ No PDF uploaded", gr.Tabs(visible=False)
    
    try:
        # Load DOLPHIN model for PDF processing
        progress(0.1, desc="Loading DOLPHIN model...")
        dolphin = load_dolphin_model()
        
        if dolphin is None:
            return "❌ Failed to load DOLPHIN model", gr.Tabs(visible=False)
        
        # Process PDF
        progress(0.2, desc="Processing PDF...")
        combined_markdown, status = process_pdf_document(pdf_file, dolphin, progress)
        
        if status == "processing_complete":
            processed_markdown = combined_markdown
            
            # Create chunks and embeddings for RAG
            progress(0.9, desc="Creating document chunks for RAG...")
            document_chunks = chunk_document(processed_markdown)
            document_embeddings = create_embeddings(document_chunks)
            print(f"Created {len(document_chunks)} chunks")
            
            # Keep DOLPHIN model loaded for GPU usage
            progress(0.95, desc="Preparing chatbot...")
            
            show_results_tab = True
            progress(1.0, desc="PDF processed successfully!")
            return "✅ PDF processed successfully! Chatbot is ready in the Chat tab.", gr.Tabs(visible=True)
        else:
            show_results_tab = False
            return combined_markdown, gr.Tabs(visible=False)
            
    except Exception as e:
        show_results_tab = False
        error_msg = f"❌ Error processing PDF: {str(e)}"
        return error_msg, gr.Tabs(visible=False)


def get_processed_markdown():
    """Return the processed markdown content"""
    global processed_markdown
    return processed_markdown if processed_markdown else "No document processed yet."


def clear_all():
    """Clear all data and hide results tab"""
    global processed_markdown, show_results_tab, document_chunks, document_embeddings
    processed_markdown = ""
    show_results_tab = False
    document_chunks = []
    document_embeddings = None
    
    # Unload DOLPHIN model
    unload_dolphin_model()
    
    return None, "", gr.Tabs(visible=False)


# Create Gradio interface
with gr.Blocks(
    title="DOLPHIN PDF AI", 
    theme=gr.themes.Soft(),
    css="""
    @import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&display=swap');
    
    * {
        font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif !important;
    }
    
    .main-container { 
        max-width: 1000px; 
        margin: 0 auto; 
    }
    .upload-container { 
        text-align: center; 
        padding: 40px 20px;
        border: 2px dashed #e0e0e0;
        border-radius: 15px;
        margin: 20px 0;
    }
    .upload-button {
        font-size: 18px !important;
        padding: 15px 30px !important;
        margin: 20px 0 !important;
        font-weight: 600 !important;
    }
    .status-message {
        text-align: center;
        padding: 15px;
        margin: 10px 0;
        border-radius: 8px;
        font-weight: 500;
    }
    .chatbot-container {
        max-height: 600px;
    }
    h1, h2, h3 {
        font-weight: 700 !important;
    }
    #progress-container {
        margin: 10px 0;
        min-height: 20px;
    }
    """
) as demo:
    
    with gr.Tabs() as main_tabs:
        # Home Tab
        with gr.TabItem("🏠 Home", id="home"):
            embedding_status = "✅ RAG ready" if embedding_model else "❌ RAG not loaded"
            gemini_status = "✅ Gemini API ready" if gemini_model else "❌ Gemini API not configured"
            current_status = f"Currently loaded: {current_model or 'None'}"
            gr.Markdown(
                "# Scholar Express\n"
                "### Upload a research paper to get a web-friendly version and an AI chatbot powered by Gemini API. DOLPHIN model runs on GPU for optimal performance.\n"
                f"**System:** {model_status}\n"
                f"**RAG System:** {embedding_status}\n"
                f"**Gemini API:** {gemini_status}\n"
                f"**Status:** {current_status}"
            )
            
            with gr.Column(elem_classes="upload-container"):
                gr.Markdown("## 📄 Upload Your PDF Document")
                
                pdf_input = gr.File(
                    file_types=[".pdf"],
                    label="",
                    height=150,
                    elem_id="pdf_upload"
                )
                
                process_btn = gr.Button(
                    "🚀 Process PDF", 
                    variant="primary", 
                    size="lg",
                    elem_classes="upload-button"
                )
                
                clear_btn = gr.Button(
                    "🗑️ Clear", 
                    variant="secondary"
                )
            
            # Dedicated progress space
            progress_space = gr.HTML(
                value="",
                visible=False,
                elem_id="progress-container"
            )
            
            # Status output (hidden during processing)
            status_output = gr.Markdown(
                "",
                elem_classes="status-message"
            )
        
        # Results Tab (initially hidden)
        with gr.TabItem("📖 Document", id="results", visible=False) as results_tab:
            gr.Markdown("## Processed Document")
            
            markdown_display = gr.Markdown(
                value="",
                latex_delimiters=[
                    {"left": "$$", "right": "$$", "display": True},
                    {"left": "$", "right": "$", "display": False}
                ],
                height=700
            )
        
        # Chatbot Tab (initially hidden)
        with gr.TabItem("💬 Chat", id="chat", visible=False) as chat_tab:
            gr.Markdown("## Ask Questions About Your Document")
            
            chatbot = gr.Chatbot(
                value=[],
                height=500,
                elem_classes="chatbot-container",
                placeholder="Your conversation will appear here once you process a document..."
            )
            
            with gr.Row():
                msg_input = gr.Textbox(
                    placeholder="Ask a question about the processed document...",
                    scale=4,
                    container=False
                )
                send_btn = gr.Button("Send", variant="primary", scale=1)
            
            gr.Markdown(
                "*Ask questions about your processed document. The AI uses RAG (Retrieval-Augmented Generation) with Gemini API to find relevant sections and provide accurate answers.*",
                elem_id="chat-notice"
            )
    
    # Event handlers
    process_btn.click(
        fn=process_uploaded_pdf,
        inputs=[pdf_input],
        outputs=[status_output, results_tab],
        show_progress=True
    ).then(
        fn=get_processed_markdown,
        outputs=[markdown_display]
    ).then(
        fn=lambda: gr.TabItem(visible=True),
        outputs=[chat_tab]
    )
    
    clear_btn.click(
        fn=clear_all,
        outputs=[pdf_input, status_output, results_tab]
    ).then(
        fn=lambda: gr.HTML(visible=False),
        outputs=[progress_space]
    ).then(
        fn=lambda: gr.TabItem(visible=False),
        outputs=[chat_tab]
    )
    
    # Chatbot functionality with Gemini API
    def chatbot_response(message, history):
        if not message.strip():
            return history
        
        if not processed_markdown:
            return history + [[message, "❌ Please process a PDF document first before asking questions."]]
        
        try:
            # Initialize Gemini model
            model = initialize_gemini_model()
            
            if model is None:
                return history + [[message, "❌ Failed to initialize Gemini model. Please check your GEMINI_API_KEY."]]
            
            # Use RAG to get relevant chunks from markdown (balanced for performance vs quota)
            if document_chunks and len(document_chunks) > 0:
                relevant_chunks = retrieve_relevant_chunks(message, document_chunks, document_embeddings, top_k=3)
                context = "\n\n".join(relevant_chunks)
                # Smart truncation: aim for ~1500 chars (good context while staying under quota)
                if len(context) > 1500:
                    # Try to cut at sentence boundaries
                    sentences = context[:1500].split('.')
                    context = '.'.join(sentences[:-1]) + '...' if len(sentences) > 1 else context[:1500] + '...'
            else:
                # Fallback to truncated document if RAG fails
                context = processed_markdown[:1200] + "..." if len(processed_markdown) > 1200 else processed_markdown
            
            # Create prompt for Gemini
            prompt = f"""You are a helpful assistant that answers questions about documents. Use the provided context to answer questions accurately and concisely.

Context from the document:
{context}

Question: {message}

Please provide a clear and helpful answer based on the context provided."""
            
            # Generate response using Gemini API with retry logic
            import time
            max_retries = 2
            
            for attempt in range(max_retries):
                try:
                    response = model.generate_content(prompt)
                    response_text = response.text if hasattr(response, 'text') else str(response)
                    return history + [[message, response_text]]
                except Exception as api_error:
                    if "429" in str(api_error) and attempt < max_retries - 1:
                        # Rate limit hit, wait and retry
                        time.sleep(3)
                        continue
                    else:
                        # Other error or final attempt failed
                        if "429" in str(api_error):
                            return history + [[message, "❌ API quota exceeded. Please wait a moment and try again, or check your Gemini API billing."]]
                        else:
                            raise api_error
            
        except Exception as e:
            error_msg = f"❌ Error generating response: {str(e)}"
            print(f"Full error: {e}")
            import traceback
            traceback.print_exc()
            return history + [[message, error_msg]]
    
    send_btn.click(
        fn=chatbot_response,
        inputs=[msg_input, chatbot],
        outputs=[chatbot]
    ).then(
        lambda: "",
        outputs=[msg_input]
    )
    
    # Also allow Enter key to send message
    msg_input.submit(
        fn=chatbot_response,
        inputs=[msg_input, chatbot],
        outputs=[chatbot]
    ).then(
        lambda: "",
        outputs=[msg_input]
    )


if __name__ == "__main__":
    demo.launch(
        server_name="0.0.0.0",
        server_port=7860,
        share=False,
        show_error=True,
        max_threads=1,  # Single thread for T4 Small
        inbrowser=False,
        quiet=True
    )