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import os
import streamlit as st
import json
import sys
import time
import base64
# Updated import section
from pathlib import Path
import tempfile
import io
from pdf2image import convert_from_bytes
from PIL import Image, ImageEnhance, ImageFilter
import cv2
import numpy as np
from datetime import datetime

# Import the StructuredOCR class and config from the local files
from structured_ocr import StructuredOCR
from config import MISTRAL_API_KEY

# Import utilities for handling previous results
from ocr_utils import create_results_zip

def get_base64_from_image(image_path):
    """Get base64 string from image file"""
    with open(image_path, "rb") as img_file:
        return base64.b64encode(img_file.read()).decode('utf-8')

# Set favicon path
favicon_path = os.path.join(os.path.dirname(__file__), "static/favicon.png")

# Set page configuration
st.set_page_config(
    page_title="Historical OCR",
    page_icon=favicon_path if os.path.exists(favicon_path) else "📜",
    layout="wide",
    initial_sidebar_state="expanded"
)

# Enable caching for expensive operations with longer TTL for better performance
@st.cache_data(ttl=24*3600, show_spinner=False)  # Cache for 24 hours instead of 1 hour
def convert_pdf_to_images(pdf_bytes, dpi=150, rotation=0):
    """Convert PDF bytes to a list of images with caching"""
    try:
        images = convert_from_bytes(pdf_bytes, dpi=dpi)
        
        # Apply rotation if specified
        if rotation != 0 and images:
            rotated_images = []
            for img in images:
                rotated_img = img.rotate(rotation, expand=True, resample=Image.BICUBIC)
                rotated_images.append(rotated_img)
            return rotated_images
        
        return images
    except Exception as e:
        st.error(f"Error converting PDF: {str(e)}")
        return []

# Cache preprocessed images for better performance
@st.cache_data(ttl=24*3600, show_spinner=False)  # Cache for 24 hours
def preprocess_image(image_bytes, preprocessing_options):
    """Preprocess image with selected options optimized for historical document OCR quality"""
    # Setup basic console logging
    import logging
    logger = logging.getLogger("image_preprocessor")
    logger.setLevel(logging.INFO)
    
    # Log which preprocessing options are being applied
    logger.info(f"Preprocessing image with options: {preprocessing_options}")
    
    # Convert bytes to PIL Image
    image = Image.open(io.BytesIO(image_bytes))
    
    # Check for alpha channel (RGBA) and convert to RGB if needed
    if image.mode == 'RGBA':
        # Convert RGBA to RGB by compositing the image onto a white background
        background = Image.new('RGB', image.size, (255, 255, 255))
        background.paste(image, mask=image.split()[3])  # 3 is the alpha channel
        image = background
        logger.info("Converted RGBA image to RGB")
    elif image.mode not in ('RGB', 'L'):
        # Convert other modes to RGB as well
        image = image.convert('RGB')
        logger.info(f"Converted {image.mode} image to RGB")
    
    # Apply rotation if specified
    if preprocessing_options.get("rotation", 0) != 0:
        rotation_degrees = preprocessing_options.get("rotation")
        image = image.rotate(rotation_degrees, expand=True, resample=Image.BICUBIC)
    
    # Resize large images while preserving details important for OCR
    width, height = image.size
    max_dimension = max(width, height)
    
    # Less aggressive resizing to preserve document details
    if max_dimension > 2500:
        scale_factor = 2500 / max_dimension
        new_width = int(width * scale_factor)
        new_height = int(height * scale_factor)
        # Use LANCZOS for better quality preservation
        image = image.resize((new_width, new_height), Image.LANCZOS)
    
    img_array = np.array(image)
    
    # Apply preprocessing based on selected options with settings optimized for historical documents
    document_type = preprocessing_options.get("document_type", "standard")
    
    # Process grayscale option first as it's a common foundation
    if preprocessing_options.get("grayscale", False):
        if len(img_array.shape) == 3:  # Only convert if it's not already grayscale
            if document_type == "handwritten":
                # Enhanced grayscale processing for handwritten documents
                img_array = cv2.cvtColor(img_array, cv2.COLOR_RGB2GRAY)
                # Apply adaptive histogram equalization to enhance handwriting
                clahe = cv2.createCLAHE(clipLimit=2.0, tileGridSize=(8,8))
                img_array = clahe.apply(img_array)
            else:
                # Standard grayscale for printed documents
                img_array = cv2.cvtColor(img_array, cv2.COLOR_RGB2GRAY)
                
            # Convert back to RGB for further processing
            img_array = cv2.cvtColor(img_array, cv2.COLOR_GRAY2RGB)
    
    if preprocessing_options.get("contrast", 0) != 0:
        contrast_factor = 1 + (preprocessing_options.get("contrast", 0) / 10)
        image = Image.fromarray(img_array)
        enhancer = ImageEnhance.Contrast(image)
        image = enhancer.enhance(contrast_factor)
        img_array = np.array(image)
    
    if preprocessing_options.get("denoise", False):
        try:
            # Apply appropriate denoising based on document type
            if document_type == "handwritten":
                # Very light denoising for handwritten documents to preserve pen strokes
                if len(img_array.shape) == 3 and img_array.shape[2] == 3:  # Color image
                    img_array = cv2.fastNlMeansDenoisingColored(img_array, None, 3, 3, 5, 9)
                else:  # Grayscale image
                    img_array = cv2.fastNlMeansDenoising(img_array, None, 3, 7, 21)
            else:
                # Standard denoising for printed documents
                if len(img_array.shape) == 3 and img_array.shape[2] == 3:  # Color image
                    img_array = cv2.fastNlMeansDenoisingColored(img_array, None, 5, 5, 7, 21)
                else:  # Grayscale image
                    img_array = cv2.fastNlMeansDenoising(img_array, None, 5, 7, 21)
        except Exception as e:
            print(f"Denoising error: {str(e)}, falling back to standard processing")
        
    # Convert back to PIL Image
    processed_image = Image.fromarray(img_array)
    
    # Higher quality for OCR processing
    byte_io = io.BytesIO()
    try:
        # Make sure the image is in RGB mode before saving as JPEG
        if processed_image.mode not in ('RGB', 'L'):
            processed_image = processed_image.convert('RGB')
        
        processed_image.save(byte_io, format='JPEG', quality=92, optimize=True)
        byte_io.seek(0)
        
        logger.info(f"Preprocessing complete. Original image mode: {image.mode}, processed mode: {processed_image.mode}")
        logger.info(f"Original size: {len(image_bytes)/1024:.1f}KB, processed size: {len(byte_io.getvalue())/1024:.1f}KB")
        
        return byte_io.getvalue()
    except Exception as e:
        logger.error(f"Error saving processed image: {str(e)}")
        # Fallback to original image
        logger.info("Using original image as fallback")
        image_io = io.BytesIO()
        image.save(image_io, format='JPEG', quality=92)
        image_io.seek(0)
        return image_io.getvalue()

# Cache OCR results in memory to speed up repeated processing
@st.cache_data(ttl=24*3600, max_entries=20, show_spinner=False)
def process_file_cached(file_path, file_type, use_vision, file_size_mb, cache_key):
    """Cached version of OCR processing to reuse results"""
    # Initialize OCR processor
    processor = StructuredOCR()
    
    # Process the file
    result = processor.process_file(
        file_path, 
        file_type=file_type, 
        use_vision=use_vision, 
        file_size_mb=file_size_mb
    )
    
    return result

# Define functions
def process_file(uploaded_file, use_vision=True, preprocessing_options=None, progress_container=None):
    """Process the uploaded file and return the OCR results
    
    Args:
        uploaded_file: The uploaded file to process
        use_vision: Whether to use vision model
        preprocessing_options: Dictionary of preprocessing options
        progress_container: Optional container for progress indicators
    """
    if preprocessing_options is None:
        preprocessing_options = {}
    
    # Create a container for progress indicators if not provided
    if progress_container is None:
        progress_container = st.empty()
        
    with progress_container.container():
        progress_bar = st.progress(0)
        status_text = st.empty()
        status_text.markdown('<div class="processing-status-container">Preparing file for processing...</div>', unsafe_allow_html=True)
    
    try:
        # Check if API key is available
        if not MISTRAL_API_KEY:
            # Return dummy data if no API key
            progress_bar.progress(100)
            status_text.empty()
            return {
                "file_name": uploaded_file.name,
                "topics": ["Document"],
                "languages": ["English"],
                "ocr_contents": {
                    "title": "API Key Required",
                    "content": "Please set the MISTRAL_API_KEY environment variable to process documents."
                }
            }
        
        # Update progress - more granular steps
        progress_bar.progress(10)
        status_text.markdown('<div class="processing-status-container">Initializing OCR processor...</div>', unsafe_allow_html=True)
        
        # Determine file type from extension
        file_ext = Path(uploaded_file.name).suffix.lower()
        file_type = "pdf" if file_ext == ".pdf" else "image"
        file_bytes = uploaded_file.getvalue()
        
        # Create a temporary file for processing
        with tempfile.NamedTemporaryFile(delete=False, suffix=file_ext) as tmp:
            tmp.write(file_bytes)
            temp_path = tmp.name
        
        # Get PDF rotation value if available and file is a PDF
        pdf_rotation_value = pdf_rotation if 'pdf_rotation' in locals() and file_type == "pdf" else 0
        
        progress_bar.progress(15)
        
        # For PDFs, we need to handle differently
        if file_type == "pdf":
            status_text.markdown('<div class="processing-status-container">Converting PDF to images...</div>', unsafe_allow_html=True)
            progress_bar.progress(20)
            
            # Convert PDF to images
            try:
                # Use the PDF processing pipeline directly from the StructuredOCR class
                processor = StructuredOCR()
                
                # Process the file with direct PDF handling
                progress_bar.progress(30)
                status_text.markdown('<div class="processing-status-container">Processing PDF with OCR...</div>', unsafe_allow_html=True)
                
                # Get file size in MB for API limits
                file_size_mb = os.path.getsize(temp_path) / (1024 * 1024)
                
                # Check if file exceeds API limits (50 MB)
                if file_size_mb > 50:
                    os.unlink(temp_path)  # Clean up temp file
                    progress_bar.progress(100)
                    status_text.empty()
                    progress_container.empty()
                    return {
                        "file_name": uploaded_file.name,
                        "topics": ["Document"],
                        "languages": ["English"],
                        "error": f"File size {file_size_mb:.2f} MB exceeds Mistral API limit of 50 MB",
                        "ocr_contents": {
                            "error": f"Failed to process file: File size {file_size_mb:.2f} MB exceeds Mistral API limit of 50 MB",
                            "partial_text": "Document could not be processed due to size limitations."
                        }
                    }
                
                # Generate cache key
                import hashlib
                file_hash = hashlib.md5(file_bytes).hexdigest()
                cache_key = f"{file_hash}_{file_type}_{use_vision}_{pdf_rotation_value}"
                
                # Process with cached function if possible
                try:
                    result = process_file_cached(temp_path, file_type, use_vision, file_size_mb, cache_key)
                    progress_bar.progress(90)
                    status_text.markdown('<div class="processing-status-container">Finalizing results...</div>', unsafe_allow_html=True)
                except Exception as e:
                    status_text.markdown(f'<div class="processing-status-container">Processing error: {str(e)}. Retrying...</div>', unsafe_allow_html=True)
                    progress_bar.progress(60)
                    # If caching fails, process directly
                    result = processor.process_file(
                        temp_path, 
                        file_type=file_type, 
                        use_vision=use_vision, 
                        file_size_mb=file_size_mb,
                    )
                    progress_bar.progress(90)
                    status_text.markdown('<div class="processing-status-container">Finalizing results...</div>', unsafe_allow_html=True)
            
            except Exception as e:
                os.unlink(temp_path)  # Clean up temp file
                progress_bar.progress(100)
                status_text.empty()
                progress_container.empty()
                raise ValueError(f"Error processing PDF: {str(e)}")
                
        else:
            # For image files, apply preprocessing if needed
            # Check if any preprocessing options with boolean values are True, or if any non-boolean values are non-default
            has_preprocessing = (
                preprocessing_options.get("grayscale", False) or
                preprocessing_options.get("denoise", False) or
                preprocessing_options.get("contrast", 0) != 0 or
                preprocessing_options.get("rotation", 0) != 0 or
                preprocessing_options.get("document_type", "standard") != "standard"
            )
            
            if has_preprocessing:
                status_text.markdown('<div class="processing-status-container">Applying image preprocessing...</div>', unsafe_allow_html=True)
                progress_bar.progress(20)
                processed_bytes = preprocess_image(file_bytes, preprocessing_options)
                progress_bar.progress(25)
                
                # Save processed image to temp file
                with tempfile.NamedTemporaryFile(delete=False, suffix=file_ext) as proc_tmp:
                    proc_tmp.write(processed_bytes)
                    # Clean up original temp file and use the processed one
                    if os.path.exists(temp_path):
                        os.unlink(temp_path)
                    temp_path = proc_tmp.name
                progress_bar.progress(30)
            else:
                progress_bar.progress(30)
            
            # Get file size in MB for API limits
            file_size_mb = os.path.getsize(temp_path) / (1024 * 1024)
            
            # Check if file exceeds API limits (50 MB)
            if file_size_mb > 50:
                os.unlink(temp_path)  # Clean up temp file
                progress_bar.progress(100)
                status_text.empty()
                progress_container.empty()
                return {
                    "file_name": uploaded_file.name,
                    "topics": ["Document"],
                    "languages": ["English"],
                    "error": f"File size {file_size_mb:.2f} MB exceeds Mistral API limit of 50 MB",
                    "ocr_contents": {
                        "error": f"Failed to process file: File size {file_size_mb:.2f} MB exceeds Mistral API limit of 50 MB",
                        "partial_text": "Document could not be processed due to size limitations."
                    }
                }
            
            # Update progress - more granular steps
            progress_bar.progress(40)
            status_text.markdown('<div class="processing-status-container">Preparing document for OCR analysis...</div>', unsafe_allow_html=True)
            
            # Generate a cache key based on file content, type and settings
            import hashlib
            # Add pdf_rotation to cache key if present
            pdf_rotation_value = pdf_rotation if 'pdf_rotation' in locals() else 0
            file_hash = hashlib.md5(open(temp_path, 'rb').read()).hexdigest()
            cache_key = f"{file_hash}_{file_type}_{use_vision}_{pdf_rotation_value}"
            
            progress_bar.progress(50)
            status_text.markdown('<div class="processing-status-container">Processing document with OCR...</div>', unsafe_allow_html=True)
            
            # Process the file using cached function if possible
            try:
                result = process_file_cached(temp_path, file_type, use_vision, file_size_mb, cache_key)
                progress_bar.progress(80)
                status_text.markdown('<div class="processing-status-container">Analyzing document structure...</div>', unsafe_allow_html=True)
                progress_bar.progress(90)
                status_text.markdown('<div class="processing-status-container">Finalizing results...</div>', unsafe_allow_html=True)
            except Exception as e:
                progress_bar.progress(60)
                status_text.markdown(f'<div class="processing-status-container">Processing error: {str(e)}. Retrying...</div>', unsafe_allow_html=True)
                # If caching fails, process directly
                processor = StructuredOCR()
                result = processor.process_file(temp_path, file_type=file_type, use_vision=use_vision, file_size_mb=file_size_mb)
                progress_bar.progress(90)
                status_text.markdown('<div class="processing-status-container">Finalizing results...</div>', unsafe_allow_html=True)
        
        # Complete progress
        progress_bar.progress(100)
        status_text.markdown('<div class="processing-status-container">Processing complete!</div>', unsafe_allow_html=True)
        time.sleep(0.8)  # Brief pause to show completion
        status_text.empty()
        progress_container.empty()  # Remove progress indicators when done
        
        # Clean up the temporary file
        if os.path.exists(temp_path):
            try:
                os.unlink(temp_path)
            except:
                pass # Ignore errors when cleaning up temporary files
        
        return result
    except Exception as e:
        progress_bar.progress(100)
        error_message = str(e)
        
        # Check for specific error types and provide helpful user-facing messages
        if "rate limit" in error_message.lower() or "429" in error_message or "requests rate limit exceeded" in error_message.lower():
            friendly_message = "The AI service is currently experiencing high demand. Please try again in a few minutes."
            logger = logging.getLogger("app")
            logger.error(f"Rate limit error: {error_message}")
            status_text.markdown(f'<div class="processing-status-container" style="border-left-color: #ff9800;">Rate Limit: {friendly_message}</div>', unsafe_allow_html=True)
        elif "quota" in error_message.lower() or "credit" in error_message.lower() or "subscription" in error_message.lower():
            friendly_message = "The API usage quota has been reached. Please check your API key and subscription limits."
            status_text.markdown(f'<div class="processing-status-container" style="border-left-color: #ef5350;">API Quota: {friendly_message}</div>', unsafe_allow_html=True)
        else:
            status_text.markdown(f'<div class="processing-status-container" style="border-left-color: #ef5350;">Error: {error_message}</div>', unsafe_allow_html=True)
        
        time.sleep(1.5)  # Show error briefly
        status_text.empty()
        progress_container.empty()
        
        # Display an appropriate error message based on the exception type
        if "rate limit" in error_message.lower() or "429" in error_message or "requests rate limit exceeded" in error_message.lower():
            st.warning(f"API Rate Limit: {friendly_message} This is a temporary issue and does not indicate any problem with your document.")
        elif "quota" in error_message.lower() or "credit" in error_message.lower() or "subscription" in error_message.lower():
            st.error(f"API Quota Exceeded: {friendly_message}")
        else:
            st.error(f"Error during processing: {error_message}")
        
        # Clean up the temporary file
        try:
            if 'temp_path' in locals() and os.path.exists(temp_path):
                os.unlink(temp_path)
        except:
            pass  # Ignore errors when cleaning up temporary files
        
        raise

# App title and description
favicon_base64 = get_base64_from_image(os.path.join(os.path.dirname(__file__), "static/favicon.png"))
st.markdown(f'<div style="display: flex; align-items: center; gap: 10px;"><img src="data:image/png;base64,{favicon_base64}" width="36" height="36" alt="Scroll Icon"/> <div><h1 style="margin: 0; padding: 20px 0 0 0;">Historical Document OCR</h1></div></div>', unsafe_allow_html=True)
st.subheader("Made possible by Mistral AI")

# Check if pytesseract is available for fallback
try:
    import pytesseract
    has_pytesseract = True
except ImportError:
    has_pytesseract = False

# Initialize session state for storing previous results if not already present
if 'previous_results' not in st.session_state:
    st.session_state.previous_results = []

# Create main layout with tabs and columns
main_tab1, main_tab2, main_tab3 = st.tabs(["Document Processing", "Previous Results", "About"])

with main_tab1:
    # Create a two-column layout for file upload and results
    left_col, right_col = st.columns([1, 1])
    
    # File uploader in the left column
    with left_col:
        # Simple CSS just to fix vertical text in drag and drop area
        st.markdown("""
        <style>
        /* Reset all file uploader styling */
        .uploadedFile, .uploadedFileData, .stFileUploader {
            color: inherit !important;
        }
        
        /* Fix vertical text orientation */
        .stFileUploader p,
        .stFileUploader span,
        .stFileUploader div p,
        .stFileUploader div span,
        .stFileUploader label p, 
        .stFileUploader label span,
        .stFileUploader div[data-testid="stFileUploadDropzone"] p,
        .stFileUploader div[data-testid="stFileUploadDropzone"] span {
            writing-mode: horizontal-tb !important;
        }
        
        /* Simplify the drop zone appearance */
        .stFileUploader > section > div,
        .stFileUploader div[data-testid="stFileUploadDropzone"] {
            min-height: 100px !important;
        }
        </style>
        """, unsafe_allow_html=True)
        
        # Add heading for the file uploader (just text, no container)
        st.markdown('### Upload Document')
        
        # Model info below the heading
        st.markdown("Using the latest `mistral-ocr-latest` model for advanced document understanding.")
        
        # Enhanced file uploader with better help text
        uploaded_file = st.file_uploader("Drag and drop PDFs or images here", type=["pdf", "png", "jpg", "jpeg"], 
                                        help="Supports PDFs, JPGs, PNGs and other image formats")
        
        # Removed seed prompt instructions from here, moving to sidebar

# Sidebar with options - moved up with equal spacing
with st.sidebar:
    # Options title with reduced top margin
    st.markdown("<h2 style='margin-top:-25px; margin-bottom:5px; padding:0;'>Options</h2>", unsafe_allow_html=True)
    
    # Reduce spacing between sidebar sections
    st.markdown("""
    <style>
    /* Reduce all spacing in sidebar */
    .block-container {padding-top: 0;}
    .stSidebar .block-container {padding-top: 0 !important;}
    .stSidebar [data-testid='stSidebarNav'] {margin-bottom: 0 !important;}
    .stSidebar [data-testid='stMarkdownContainer'] {margin-bottom: 0 !important; margin-top: 0 !important;}
    .stSidebar [data-testid='stVerticalBlock'] {gap: 0 !important;}
    
    /* Make checkbox rows more compact */
    .stCheckbox {margin-bottom: 0 !important; padding-bottom: 0 !important; padding-top: 0 !important;}
    .stExpander {margin-top: 0 !important; margin-bottom: 10px !important;}
    
    /* Reduce space between section headings and content */
    .stSidebar h1, .stSidebar h2, .stSidebar h3, .stSidebar h4, .stSidebar h5 {
        margin-top: 0 !important;
        margin-bottom: 0 !important;
        padding-top: 0 !important;
        padding-bottom: 0 !important;
        line-height: 1.2 !important;
    }
    
    /* Make selectbox and other inputs more compact */
    .stSidebar .stSelectbox, .stSidebar .stSlider, .stSidebar .stNumberInput {
        margin-bottom: 5px !important;
        padding-bottom: 0 !important;
        padding-top: 0 !important;
    }
    
    /* Reduce all form element margins */
    .stForm > div {margin-bottom: 5px !important;}
    .stSidebar label {margin-bottom: 0 !important; line-height: 1.2 !important;}
    </style>
    """, unsafe_allow_html=True)
    
    # Model options - more compact
    st.markdown("##### Model Settings", help="Configure model options")
    use_vision = st.checkbox("Use Vision Model", value=True, 
                            help="For image files, use the vision model for improved analysis (may be slower)")
    
    # Historical Context section with minimal spacing
    st.markdown("##### Historical Context", help="Add historical context information")
    
    # Historical period selector
    historical_periods = [
        "Select period (if known)",
        "Pre-1700s",
        "18th Century (1700s)",
        "19th Century (1800s)",
        "Early 20th Century (1900-1950)",
        "Modern (Post 1950)"
    ]
    
    selected_period = st.selectbox(
        "Historical Period", 
        options=historical_periods,
        index=0,
        help="Select the time period of the document for better OCR processing"
    )
    
    # Document purpose selector
    document_purposes = [
        "Select purpose (if known)",
        "Personal Letter/Correspondence",
        "Official/Government Document",
        "Business/Financial Record",
        "Literary/Academic Work", 
        "News/Journalism",
        "Religious Text",
        "Legal Document"
    ]
    
    selected_purpose = st.selectbox(
        "Document Purpose",
        options=document_purposes,
        index=0,
        help="Select the purpose or type of the document for better OCR processing"
    )
    
    # Custom prompt field
    custom_prompt_text = ""
    if selected_period != "Select period (if known)":
        custom_prompt_text += f"This is a {selected_period} document. "
        
    if selected_purpose != "Select purpose (if known)":
        custom_prompt_text += f"It appears to be a {selected_purpose}. "
    
    custom_prompt = st.text_area(
        "Additional Context", 
        value=custom_prompt_text,
        placeholder="Example: This document has unusual handwriting with cursive script. Please identify any mentioned locations and dates.",
        height=150,
        max_chars=500,
        key="custom_analysis_instructions",
        help="Powerful instructions field that impacts how the AI processes your document. Can request translations, format images correctly, extract specific information, or handle challenging documents. See the 'Additional Context Instructions & Examples' section below for more details."
    )
    
    # Enhanced instructions for Additional Context with more capabilities
    with st.expander("Prompting Instructions"):
        st.markdown("""
        ### How Additional Context Affects Processing

        The "Additional Context" field provides instructions directly to the AI to influence how it processes your document. Use it to:
        
        #### Document Understanding
        - **Specify handwriting styles**: "This document uses old-fashioned cursive with numerous flourishes and abbreviations"
        - **Identify language features**: "The text contains archaic spellings common in 18th century documents"
        - **Highlight focus areas**: "Look for mentions of financial transactions or dates of travel"
        
        #### Output Formatting & Languages
        - **Request translations**: "After extracting the text, translate the content into Spanish"
        - **Format image orientation**: "Ensure images are displayed in the same orientation as they appear in the document"
        - **Format tables**: "Convert any tables in the document to structured format with clear columns"
        
        #### Special Processing
        - **Handle challenges**: "Some portions may be faded; the page edges contain handwritten notes"
        - **Technical terms**: "This is a medical document with specialized terminology about surgical procedures"
        - **Organization**: "Separate the letter content from the address blocks and signature"
        
        #### Example Combinations
        ```
        This is a handwritten letter from the 1850s. The writer uses archaic spellings and formal language.
        Please preserve paragraph structure, identify any place names mentioned, and note any references
        to historical events. Format any lists as bullet points.
        ```
        """)
    
    # Image preprocessing options with reduced spacing
    st.markdown("##### Image Preprocessing", help="Options for enhancing images before OCR")
    with st.expander("Preprocessing Options", expanded=False):
        preprocessing_options = {}
        
        # Document type selector - important for optimized processing
        doc_type_options = ["standard", "handwritten", "typed", "printed"]
        preprocessing_options["document_type"] = st.selectbox(
            "Document Type",
            options=doc_type_options,
            index=0,  # Default to standard
            format_func=lambda x: x.capitalize(),
            help="Select document type for optimized processing - choose 'Handwritten' for letters and manuscripts"
        )
        
        preprocessing_options["grayscale"] = st.checkbox("Convert to Grayscale", 
                                                        help="Convert image to grayscale before OCR")
        preprocessing_options["denoise"] = st.checkbox("Denoise Image", 
                                                     help="Remove noise from the image")
        preprocessing_options["contrast"] = st.slider("Adjust Contrast", -5, 5, 0, 
                                                    help="Adjust image contrast (-5 to +5)")
        
        # Add rotation options
        rotation_options = [0, 90, 180, 270]
        preprocessing_options["rotation"] = st.select_slider(
            "Rotate Document",
            options=rotation_options,
            value=0,
            format_func=lambda x: f"{x}° {'(No rotation)' if x == 0 else ''}",
            help="Rotate the document to correct orientation"
        )
    
    # PDF options with consistent formatting
    st.markdown("##### PDF Options", help="Settings for PDF documents")
    with st.expander("PDF Settings", expanded=False):
        pdf_dpi = st.slider("PDF Resolution (DPI)", 72, 300, 100, 
                          help="Higher DPI gives better quality but slower processing. Try 100 for faster processing.")
        max_pages = st.number_input("Maximum Pages to Process", 1, 20, 3, 
                                  help="Limit number of pages to process")
        
        # Add PDF rotation option
        rotation_options = [0, 90, 180, 270]
        pdf_rotation = st.select_slider(
            "Rotate PDF",
            options=rotation_options,
            value=0,
            format_func=lambda x: f"{x}° {'(No rotation)' if x == 0 else ''}",
            help="Rotate the PDF pages to correct orientation"
        )
        
        # Store PDF rotation separately instead of in preprocessing_options
        # This prevents conflict with image preprocessing

# Previous Results tab content
with main_tab2:
    st.markdown('<h2>Previous Results</h2>', unsafe_allow_html=True)
    
    # Load custom CSS for Previous Results tab
    from ui.layout import load_css
    load_css()
    
    # Display previous results if available
    if not st.session_state.previous_results:
        st.markdown("""
        <div class="previous-results-container" style="text-align: center; padding: 40px 20px; background-color: #f0f2f6; border-radius: 8px;">
            <div style="font-size: 48px; margin-bottom: 20px;">📄</div>
            <h3 style="margin-bottom: 10px; font-weight: 600;">No Previous Results</h3>
            <p style="font-size: 16px;">Process a document to see your results history saved here.</p>
        </div>
        """, unsafe_allow_html=True)
    else:
        # Create a container for the results list
        st.markdown('<div class="previous-results-container">', unsafe_allow_html=True)
        st.markdown(f'<h3>{len(st.session_state.previous_results)} Previous Results</h3>', unsafe_allow_html=True)
        
        # Create two columns for filters and download buttons
        filter_col, download_col = st.columns([2, 1])
        
        with filter_col:
            # Add filter options
            filter_options = ["All Types"]
            if any(result.get("file_name", "").lower().endswith(".pdf") for result in st.session_state.previous_results):
                filter_options.append("PDF Documents")
            if any(result.get("file_name", "").lower().endswith((".jpg", ".jpeg", ".png")) for result in st.session_state.previous_results):
                filter_options.append("Images")
                
            selected_filter = st.selectbox("Filter by Type:", filter_options)
        
        with download_col:
            # Add download all button for results
            if len(st.session_state.previous_results) > 0:
                try:
                    # Create buffer in memory instead of file on disk
                    import io
                    from ocr_utils import create_results_zip_in_memory
                    
                    # Get zip data directly in memory
                    zip_data = create_results_zip_in_memory(st.session_state.previous_results)
                    
                    st.download_button(
                        label="Download All Results",
                        data=zip_data,
                        file_name="all_ocr_results.zip",
                        mime="application/zip",
                        help="Download all previous results as a ZIP file containing HTML and JSON files"
                    )
                except Exception as e:
                    st.error(f"Error creating download: {str(e)}")
                    st.info("Try with fewer results or individual downloads")
        
        # Filter results based on selection
        filtered_results = st.session_state.previous_results
        if selected_filter == "PDF Documents":
            filtered_results = [r for r in st.session_state.previous_results if r.get("file_name", "").lower().endswith(".pdf")]
        elif selected_filter == "Images":
            filtered_results = [r for r in st.session_state.previous_results if r.get("file_name", "").lower().endswith((".jpg", ".jpeg", ".png"))]
        
        # Show a message if no results match the filter
        if not filtered_results:
            st.markdown("""
            <div style="text-align: center; padding: 20px; background-color: #f9f9f9; border-radius: 5px; margin: 20px 0;">
                <p>No results match the selected filter.</p>
            </div>
            """, unsafe_allow_html=True)
        
        # Display each result as a card
        for i, result in enumerate(filtered_results):
            # Determine file type icon
            file_name = result.get("file_name", f"Document {i+1}")
            file_type_lower = file_name.lower()
            
            if file_type_lower.endswith(".pdf"):
                icon = "📄"
            elif file_type_lower.endswith((".jpg", ".jpeg", ".png", ".gif")):
                icon = "🖼️"
            else:
                icon = "📝"
            
            # Create a card for each result
            st.markdown(f"""
            <div class="result-card">
                <div class="result-header">
                    <div class="result-filename">{icon} {file_name}</div>
                    <div class="result-date">{result.get('timestamp', 'Unknown')}</div>
                </div>
                <div class="result-metadata">
                    <div class="result-tag">Languages: {', '.join(result.get('languages', ['Unknown']))}</div>
                    <div class="result-tag">Topics: {', '.join(result.get('topics', ['Unknown']))}</div>
                </div>
            """, unsafe_allow_html=True)
            
            # Add view button inside the card with proper styling
            st.markdown('<div class="result-action-button">', unsafe_allow_html=True)
            if st.button(f"View Document", key=f"view_{i}"):
                # Set the selected result in the session state
                st.session_state.selected_previous_result = st.session_state.previous_results[i]
                # Force a rerun to show the selected result
                st.rerun()
            st.markdown('</div>', unsafe_allow_html=True)
            
            # Close the result card
            st.markdown('</div>', unsafe_allow_html=True)
        
        # Close the container
        st.markdown('</div>', unsafe_allow_html=True)
        
        # Display the selected result if available
        if 'selected_previous_result' in st.session_state and st.session_state.selected_previous_result:
            selected_result = st.session_state.selected_previous_result
            
            # Create a styled container for the selected result
            st.markdown(f"""
            <div class="selected-result-container">
                <div class="result-header" style="margin-bottom: 20px;">
                    <div class="selected-result-title">Selected Document: {selected_result.get('file_name', 'Unknown')}</div>
                    <div class="result-date">{selected_result.get('timestamp', '')}</div>
                </div>
            """, unsafe_allow_html=True)
            
            # Display metadata in a styled way
            meta_col1, meta_col2 = st.columns(2)
            
            with meta_col1:
                # Display document metadata
                if 'languages' in selected_result:
                    languages = [lang for lang in selected_result['languages'] if lang is not None]
                    if languages:
                        st.write(f"**Languages:** {', '.join(languages)}")
                
                if 'topics' in selected_result and selected_result['topics']:
                    st.write(f"**Topics:** {', '.join(selected_result['topics'])}")
            
            with meta_col2:
                # Display processing metadata
                if 'limited_pages' in selected_result:
                    st.info(f"Processed {selected_result['limited_pages']['processed']} of {selected_result['limited_pages']['total']} pages")
                
                if 'processing_time' in selected_result:
                    proc_time = selected_result['processing_time']
                    st.write(f"**Processing Time:** {proc_time:.1f}s")
            
            # Create tabs for content display
            has_images = selected_result.get('has_images', False)
            if has_images:
                view_tab1, view_tab2, view_tab3 = st.tabs(["Structured View", "Raw JSON", "With Images"])
            else:
                view_tab1, view_tab2 = st.tabs(["Structured View", "Raw JSON"])
            
            with view_tab1:
                # Display structured content
                if 'ocr_contents' in selected_result and isinstance(selected_result['ocr_contents'], dict):
                    for section, content in selected_result['ocr_contents'].items():
                        if content and section not in ['error', 'raw_text', 'partial_text']:  # Skip error and raw text sections
                            st.markdown(f"#### {section.replace('_', ' ').title()}")
                            
                            if isinstance(content, str):
                                st.write(content)
                            elif isinstance(content, list):
                                for item in content:
                                    if isinstance(item, str):
                                        st.write(f"- {item}")
                                    else:
                                        st.write(f"- {str(item)}")
                            elif isinstance(content, dict):
                                for k, v in content.items():
                                    st.write(f"**{k}:** {v}")
            
            with view_tab2:
                # Show the raw JSON with an option to download it
                try:
                    st.json(selected_result)
                except Exception as e:
                    st.error(f"Error displaying JSON: {str(e)}")
                    # Try a safer approach with string representation
                    st.code(str(selected_result))
                
                # Add JSON download button
                try:
                    json_str = json.dumps(selected_result, indent=2)
                    filename = selected_result.get('file_name', 'document').split('.')[0]
                    st.download_button(
                        label="Download JSON",
                        data=json_str,
                        file_name=f"{filename}_data.json",
                        mime="application/json"
                    )
                except Exception as e:
                    st.error(f"Error creating JSON download: {str(e)}")
                    # Fallback to string representation for download
                    st.download_button(
                        label="Download as Text",
                        data=str(selected_result),
                        file_name=f"{filename}_data.txt", 
                        mime="text/plain"
                    )
            
            if has_images and 'pages_data' in selected_result:
                with view_tab3:
                    # Display content with images in a nicely formatted way
                    pages_data = selected_result.get('pages_data', [])
                    
                    # Process and display each page
                    for page_idx, page in enumerate(pages_data):
                        # Add a page header if multi-page
                        if len(pages_data) > 1:
                            st.markdown(f"### Page {page_idx + 1}")
                        
                        # Create columns for better layout
                        if page.get('images'):
                            # Extract images for this page
                            images = page.get('images', [])
                            for img in images:
                                if 'image_base64' in img:
                                    st.image(img['image_base64'], width=600)
                            
                            # Display text content if available
                            text_content = page.get('markdown', '')
                            if text_content:
                                with st.expander("View Page Text", expanded=True):
                                    st.markdown(text_content)
                        else:
                            # Just display text if no images
                            text_content = page.get('markdown', '')
                            if text_content:
                                st.markdown(text_content)
                        
                        # Add page separator
                        if page_idx < len(pages_data) - 1:
                            st.markdown("---")
                    
                    # Add HTML download button if images are available
                    from ocr_utils import create_html_with_images
                    html_content = create_html_with_images(selected_result)
                    filename = selected_result.get('file_name', 'document').split('.')[0]
                    st.download_button(
                        label="Download as HTML with Images",
                        data=html_content,
                        file_name=f"{filename}_with_images.html",
                        mime="text/html"
                    )
            
            # Close the container
            st.markdown('</div>', unsafe_allow_html=True)
            
            # Add clear button outside the container with proper styling
            col1, col2, col3 = st.columns([1, 1, 1])
            with col2:
                st.markdown('<div class="result-action-button" style="text-align: center;">', unsafe_allow_html=True)
                if st.button("Close Selected Document", key="close_selected"):
                    # Clear the selected result from session state
                    del st.session_state.selected_previous_result
                    # Force a rerun to update the view
                    st.rerun()
                st.markdown('</div>', unsafe_allow_html=True)

# About tab content
with main_tab3:
    # Add a notice about local OCR fallback if available
    fallback_notice = ""
    if 'has_pytesseract' in locals() and has_pytesseract:
        fallback_notice = """
    **Local OCR Fallback:**
    - Local OCR fallback using Tesseract is available if API rate limits are reached
    - Provides basic text extraction when cloud OCR is unavailable
    """
    
    st.markdown(f"""
    ### About Historical Document OCR
    
    This application specializes in processing historical documents using [Mistral AI's Document OCR](https://docs.mistral.ai/capabilities/document/), which is particularly effective for handling challenging textual materials.
    
    #### Document Processing Capabilities
    - **Historical Images**: Process vintage photographs, scanned historical papers, manuscripts
    - **Handwritten Documents**: Extract text from letters, journals, notes, and records
    - **Multi-Page PDFs**: Process historical books, articles, and longer documents
    - **Mixed Content**: Handle documents with both text and imagery
    
    #### Key Features
    - **Advanced Image Preprocessing**
      - Grayscale conversion optimized for historical documents
      - Denoising to remove artifacts and improve clarity
      - Contrast adjustment to enhance faded text
      - Document rotation for proper orientation
    
    - **Document Analysis**
      - Text extraction with `mistral-ocr-latest`
      - Structured data extraction: dates, names, places, topics
      - Multi-language support with automatic detection
      - Handling of period-specific terminology and obsolete language
    
    - **Flexible Output Formats**
      - Structured view with organized content sections
      - Developer JSON for integration with other applications
      - Visual representation preserving original document layout
      - Downloadable results in various formats
    
    #### Historical Context
    Add period-specific context to improve analysis:
    - Historical period selection
    - Document purpose identification
    - Custom instructions for specialized terminology
    
    #### Data Privacy
    - All document processing happens through secure AI processing
    - No documents are permanently stored on the server
    - Results are only saved in your current session
    {fallback_notice}
    """)

with main_tab1:
    if uploaded_file is not None:
        # Check file size (cap at 50MB)
        file_size_mb = len(uploaded_file.getvalue()) / (1024 * 1024)
        
        if file_size_mb > 50:
            with left_col:
                st.error(f"File too large ({file_size_mb:.1f} MB). Maximum file size is 50MB.")
            st.stop()
        
        file_ext = Path(uploaded_file.name).suffix.lower()
        
        # Process button - flush left with similar padding as file browser
        with left_col:
            process_button = st.button("Process Document")
            
            # Empty container for progress indicators - will be filled during processing
            # Positioned right after the process button for better visibility
            progress_placeholder = st.empty()
            
            # Image preprocessing preview - automatically show only the preprocessed version
            if any(preprocessing_options.values()) and uploaded_file.type.startswith('image/'):
                st.markdown("**Preprocessed Preview**")
                try:
                    # Create a container for the preview to better control layout
                    with st.container():
                        processed_bytes = preprocess_image(uploaded_file.getvalue(), preprocessing_options)
                        # Use use_column_width=True for responsive design
                        st.image(io.BytesIO(processed_bytes), use_column_width=True)
                    
                    # Show preprocessing metadata in a well-formatted caption
                    meta_items = []
                    if preprocessing_options.get("document_type", "standard") != "standard":
                        meta_items.append(f"Document type ({preprocessing_options['document_type']})")
                    if preprocessing_options.get("grayscale", False):
                        meta_items.append("Grayscale")
                    if preprocessing_options.get("denoise", False):
                        meta_items.append("Denoise")
                    if preprocessing_options.get("contrast", 0) != 0:
                        meta_items.append(f"Contrast ({preprocessing_options['contrast']})")
                    if preprocessing_options.get("rotation", 0) != 0:
                        meta_items.append(f"Rotation ({preprocessing_options['rotation']}°)")
                    
                    # Only show "Applied:" if there are actual preprocessing steps
                    if meta_items:
                        meta_text = "Applied: " + ", ".join(meta_items)
                        st.caption(meta_text)
                except Exception as e:
                    st.error(f"Error in preprocessing: {str(e)}")
                    st.info("Try using grayscale preprocessing for PNG images with transparency")
            
            # Container for success message (will be filled after processing)
            # No extra spacing needed as it will be managed programmatically
            metadata_placeholder = st.empty()
        
        # Results section
        if process_button:
            # Move the progress indicator reference to just below the button
            progress_container = progress_placeholder
            try:
                # Get max_pages or default if not available
                max_pages_value = max_pages if 'max_pages' in locals() else None
                
                # Apply performance mode settings
                if 'perf_mode' in locals():
                    if perf_mode == "Speed":
                        # Override settings for faster processing
                        if 'preprocessing_options' in locals():
                            preprocessing_options["denoise"] = False  # Skip denoising for speed
                        if 'pdf_dpi' in locals() and file_ext.lower() == '.pdf':
                            pdf_dpi = min(pdf_dpi, 100)  # Lower DPI for speed
                
                # Process file with or without custom prompt
                if custom_prompt and custom_prompt.strip():
                    # Process with custom instructions for the AI
                    with progress_placeholder.container():
                        progress_bar = st.progress(0)
                        status_text = st.empty()
                        status_text.markdown('<div class="processing-status-container">Processing with custom instructions...</div>', unsafe_allow_html=True)
                        progress_bar.progress(30)
                    
                    # Special handling for PDF files with custom prompts
                    if file_ext.lower() == ".pdf":
                        # For PDFs with custom prompts, we use a special two-step process
                        with progress_placeholder.container():
                            status_text.markdown('<div class="processing-status-container">Using special PDF processing for custom instructions...</div>', unsafe_allow_html=True)
                            progress_bar.progress(40)
                            
                            try:
                                # Step 1: Process without custom prompt to get OCR text
                                processor = StructuredOCR()
                                
                                # First save the PDF to a temp file
                                with tempfile.NamedTemporaryFile(delete=False, suffix=".pdf") as tmp:
                                    tmp.write(uploaded_file.getvalue())
                                    temp_path = tmp.name
                                
                                # Process with NO custom prompt first
                                # Apply PDF rotation if specified
                                pdf_rotation_value = pdf_rotation if 'pdf_rotation' in locals() else 0
                                
                                base_result = processor.process_file(
                                    file_path=temp_path,
                                    file_type="pdf",
                                    use_vision=use_vision,
                                    custom_prompt=None,  # No custom prompt in first step
                                    file_size_mb=len(uploaded_file.getvalue()) / (1024 * 1024),
                                    pdf_rotation=pdf_rotation_value  # Pass rotation value to processor
                                )
                                
                                progress_bar.progress(70)
                                status_text.markdown('<div class="processing-status-container">Applying custom analysis to extracted text...</div>', unsafe_allow_html=True)
                                
                                # Step 2: Apply custom prompt to the extracted text using text-only LLM
                                if 'ocr_contents' in base_result and isinstance(base_result['ocr_contents'], dict):
                                    # Get text from OCR result
                                    ocr_text = ""
                                    for section, content in base_result['ocr_contents'].items():
                                        if isinstance(content, str):
                                            ocr_text += content + "\n\n"
                                        elif isinstance(content, list):
                                            for item in content:
                                                if isinstance(item, str):
                                                    ocr_text += item + "\n"
                                            ocr_text += "\n"
                                    
                                    # Format the custom prompt for text-only processing
                                    formatted_prompt = f"USER INSTRUCTIONS: {custom_prompt.strip()}\nPay special attention to these instructions and respond accordingly."
                                    
                                    # Apply custom prompt to extracted text
                                    enhanced_result = processor._extract_structured_data_text_only(ocr_text, uploaded_file.name, formatted_prompt)
                                    
                                    # Merge results, keeping images from base_result
                                    result = base_result.copy()
                                    result['custom_prompt_applied'] = 'text_only'
                                    
                                    # Update with enhanced analysis results, preserving image data
                                    for key, value in enhanced_result.items():
                                        if key not in ['raw_response_data', 'pages_data', 'has_images']:
                                            result[key] = value
                                else:
                                    # If no OCR content, just use the base result
                                    result = base_result
                                    result['custom_prompt_applied'] = 'failed'
                                    
                                # Clean up temp file
                                if os.path.exists(temp_path):
                                    os.unlink(temp_path)
                                    
                            except Exception as e:
                                # If anything fails, revert to standard processing
                                st.warning(f"Special PDF processing failed. Falling back to standard method: {str(e)}")
                                result = process_file(uploaded_file, use_vision, {}, progress_container=progress_placeholder)
                    else:
                        # For non-PDF files, use normal processing with custom prompt
                        # Save the uploaded file to a temporary file with preprocessing
                        with tempfile.NamedTemporaryFile(delete=False, suffix=Path(uploaded_file.name).suffix) as tmp:
                            # Apply preprocessing if any options are selected
                            if any(preprocessing_options.values()):
                                # Apply performance mode settings
                                if 'perf_mode' in locals() and perf_mode == "Speed":
                                    # Skip denoising for speed in preprocessing
                                    speed_preprocessing = preprocessing_options.copy()
                                    speed_preprocessing["denoise"] = False
                                    processed_bytes = preprocess_image(uploaded_file.getvalue(), speed_preprocessing)
                                else:
                                    processed_bytes = preprocess_image(uploaded_file.getvalue(), preprocessing_options)
                                tmp.write(processed_bytes)
                            else:
                                tmp.write(uploaded_file.getvalue())
                            temp_path = tmp.name
                        
                        # Show progress
                        with progress_placeholder.container():
                            progress_bar.progress(50)
                            status_text.markdown('<div class="processing-status-container">Analyzing with custom instructions...</div>', unsafe_allow_html=True)
                        
                        # Initialize OCR processor and process with custom prompt
                        processor = StructuredOCR()
                        
                        # Format the custom prompt to ensure it has an impact
                        formatted_prompt = f"USER INSTRUCTIONS: {custom_prompt.strip()}\nPay special attention to these instructions and respond accordingly."
                        
                        try:
                            result = processor.process_file(
                                file_path=temp_path,
                                file_type="image",  # Always use image for non-PDFs
                                use_vision=use_vision,
                                custom_prompt=formatted_prompt,
                                file_size_mb=len(uploaded_file.getvalue()) / (1024 * 1024)
                            )
                        except Exception as e:
                            # For any error, fall back to standard processing
                            st.warning(f"Custom prompt processing failed. Falling back to standard processing: {str(e)}")
                            result = process_file(uploaded_file, use_vision, preprocessing_options, progress_container=progress_placeholder)
                    
                    # Complete progress
                    with progress_placeholder.container():
                        progress_bar.progress(100)
                        status_text.markdown('<div class="processing-status-container">Processing complete!</div>', unsafe_allow_html=True)
                        time.sleep(0.8)
                        progress_placeholder.empty()
                    
                    # Clean up temporary file
                    if os.path.exists(temp_path):
                        try:
                            os.unlink(temp_path)
                        except:
                            pass
                else:
                    # Standard processing without custom prompt
                    result = process_file(uploaded_file, use_vision, preprocessing_options, progress_container=progress_placeholder)
                
                # Document results will be shown in the right column
                with right_col:
                    
                    # Add Document Metadata section header
                    st.subheader("Document Metadata")
                    
                    # Create metadata card with standard styling
                    metadata_html = '<div class="metadata-card" style="padding:15px; margin-bottom:20px;">'
                    
                    # File info
                    metadata_html += f'<p><strong>File Name:</strong> {result.get("file_name", uploaded_file.name)}</p>'
                    
                    # Info about limited pages
                    if 'limited_pages' in result:
                        metadata_html += f'<p style="padding:8px; border-radius:4px;"><strong>Pages:</strong> {result["limited_pages"]["processed"]} of {result["limited_pages"]["total"]} processed</p>'
                    
                    # Languages
                    if 'languages' in result:
                        languages = [lang for lang in result['languages'] if lang is not None]
                        if languages:
                            metadata_html += f'<p><strong>Languages:</strong> {", ".join(languages)}</p>'
                    
                    # Topics
                    if 'topics' in result and result['topics']:
                        metadata_html += f'<p><strong>Topics:</strong> {", ".join(result["topics"])}</p>'
                    
                    # Processing time
                    if 'processing_time' in result:
                        proc_time = result['processing_time']
                        metadata_html += f'<p><strong>Processing Time:</strong> {proc_time:.1f}s</p>'
                    
                    # Close the metadata card
                    metadata_html += '</div>'
                    
                    # Render the metadata HTML
                    st.markdown(metadata_html, unsafe_allow_html=True)
                    
                    # Add content section heading - using standard subheader
                    st.subheader("Document Content")
                    
                    # Start document content div with consistent styling class
                    st.markdown('<div class="document-content" style="margin-top:10px;">', unsafe_allow_html=True)
                    if 'ocr_contents' in result:
                        # Check for has_images in the result
                        has_images = result.get('has_images', False)
                        
                        # Create tabs for different views
                        if has_images:
                            view_tab1, view_tab2, view_tab3 = st.tabs(["Structured View", "Raw JSON", "With Images"])
                        else:
                            view_tab1, view_tab2 = st.tabs(["Structured View", "Raw JSON"])
                    
                    with view_tab1:
                        # Display in a more user-friendly format based on the content structure
                        html_content = ""
                        if isinstance(result['ocr_contents'], dict):
                            for section, content in result['ocr_contents'].items():
                                if content:  # Only display non-empty sections
                                    # Add consistent styling for each section
                                    section_title = f'<h4 style="font-family: Georgia, serif; font-size: 18px; margin-top: 20px; margin-bottom: 10px;">{section.replace("_", " ").title()}</h4>'
                                    html_content += section_title
                                    
                                    if isinstance(content, str):
                                        # Optimize by using a expander for very long content
                                        if len(content) > 1000:
                                            # Format content for long text - bold everything after "... that"
                                            preview_content = content[:1000] + "..." if len(content) > 1000 else content
                                            
                                            if "... that" in content:
                                                # For the preview (first 1000 chars)
                                                if "... that" in preview_content:
                                                    parts = preview_content.split("... that", 1)
                                                    formatted_preview = f"{parts[0]}... that<strong>{parts[1]}</strong>"
                                                    html_content += f"<p style=\"font-size:16px;\">{formatted_preview}</p>"
                                                else:
                                                    html_content += f"<p style=\"font-size:16px; font-weight:normal;\">{preview_content}</p>"
                                                
                                                # For the full content in expander
                                                parts = content.split("... that", 1)
                                                formatted_full = f"{parts[0]}... that**{parts[1]}**"
                                                
                                                st.markdown(f"#### {section.replace('_', ' ').title()}")
                                                with st.expander("Show full content"):
                                                    st.markdown(formatted_full)
                                            else:
                                                html_content += f"<p style=\"font-size:16px; font-weight:normal;\">{preview_content}</p>"
                                                st.markdown(f"#### {section.replace('_', ' ').title()}")
                                                with st.expander("Show full content"):
                                                    st.write(content)
                                        else:
                                            # Format content - bold everything after "... that"
                                            if "... that" in content:
                                                parts = content.split("... that", 1)
                                                formatted_content = f"{parts[0]}... that<strong>{parts[1]}</strong>"
                                                html_content += f"<p style=\"font-size:16px;\">{formatted_content}</p>"
                                                st.markdown(f"#### {section.replace('_', ' ').title()}")
                                                st.markdown(f"{parts[0]}... that**{parts[1]}**")
                                            else:
                                                html_content += f"<p style=\"font-size:16px; font-weight:normal;\">{content}</p>"
                                                st.markdown(f"#### {section.replace('_', ' ').title()}")
                                                st.write(content)
                                    elif isinstance(content, list):
                                        html_list = "<ul>"
                                        st.markdown(f"#### {section.replace('_', ' ').title()}")
                                        # Limit display for very long lists
                                        if len(content) > 20:
                                            with st.expander(f"Show all {len(content)} items"):
                                                for item in content:
                                                    if isinstance(item, str):
                                                        html_list += f"<li>{item}</li>"
                                                        st.write(f"- {item}")
                                                    elif isinstance(item, dict):
                                                        try:
                                                            st.json(item)
                                                        except Exception as e:
                                                            st.error(f"Error displaying JSON: {str(e)}")
                                                            st.code(str(item))
                                        else:
                                            for item in content:
                                                if isinstance(item, str):
                                                    html_list += f"<li>{item}</li>"
                                                    st.write(f"- {item}")
                                                elif isinstance(item, dict):
                                                    try:
                                                        st.json(item)
                                                    except Exception as e:
                                                        st.error(f"Error displaying JSON: {str(e)}")
                                                        st.code(str(item))
                                        html_list += "</ul>"
                                        html_content += html_list
                                    elif isinstance(content, dict):
                                        html_dict = "<dl>"
                                        st.markdown(f"#### {section.replace('_', ' ').title()}")
                                        for k, v in content.items():
                                            html_dict += f"<dt>{k}</dt><dd>{v}</dd>"
                                            st.write(f"**{k}:** {v}")
                                        html_dict += "</dl>"
                                        html_content += html_dict
                        
                        # Add download button in a smaller section
                        with st.expander("Export Content"):
                            # Get original filename without extension
                            original_name = Path(result.get('file_name', uploaded_file.name)).stem
                            # HTML download button
                            html_bytes = html_content.encode()
                            st.download_button(
                                label="Download as HTML",
                                data=html_bytes,
                                file_name=f"{original_name}_processed.html",
                                mime="text/html"
                            )
                    
                    with view_tab2:
                        # Show the raw JSON for developers, with an expander for large results
                        if len(json.dumps(result)) > 5000:
                            with st.expander("View full JSON"):
                                try:
                                    st.json(result)
                                except Exception as e:
                                    st.error(f"Error displaying JSON: {str(e)}")
                                    # Fallback to string representation 
                                    st.code(str(result))
                        else:
                            try:
                                st.json(result)
                            except Exception as e:
                                st.error(f"Error displaying JSON: {str(e)}")
                                # Fallback to string representation
                                st.code(str(result))
                    
                    if has_images and 'pages_data' in result:
                        with view_tab3:
                            # Use pages_data directly instead of raw_response
                            try:
                                # Use the serialized pages data
                                pages_data = result.get('pages_data', [])
                                if not pages_data:
                                    st.warning("No image data found in the document.")
                                    st.stop()
                                
                                # Construct markdown from pages_data directly
                                from ocr_utils import replace_images_in_markdown
                                combined_markdown = ""
                                
                                for page in pages_data:
                                    page_markdown = page.get('markdown', '')
                                    images = page.get('images', [])
                                    
                                    # Create image dictionary
                                    image_dict = {}
                                    for img in images:
                                        if 'id' in img and 'image_base64' in img:
                                            image_dict[img['id']] = img['image_base64']
                                    
                                    # Replace image references in markdown
                                    if page_markdown and image_dict:
                                        page_markdown = replace_images_in_markdown(page_markdown, image_dict)
                                        combined_markdown += page_markdown + "\n\n---\n\n"
                                
                                if not combined_markdown:
                                    st.warning("No content with images found.")
                                    st.stop()
                                
                                # Add CSS for better image handling
                                st.markdown("""
                                <style>
                                .image-container {
                                    margin: 20px 0;
                                    text-align: center;
                                }
                                .markdown-text-container {
                                    padding: 10px;
                                    background-color: #f9f9f9;
                                    border-radius: 5px;
                                }
                                .markdown-text-container img {
                                    margin: 15px auto;
                                    max-width: 90%;
                                    max-height: 500px;
                                    object-fit: contain;
                                    border: 1px solid #ddd;
                                    border-radius: 4px;
                                    display: block;
                                }
                                .markdown-text-container p {
                                    margin-bottom: 16px;
                                    line-height: 1.6;
                                    font-family: Georgia, serif;
                                }
                                .page-break {
                                    border-top: 1px solid #ddd;
                                    margin: 20px 0;
                                    padding-top: 20px;
                                }
                                .page-text-content {
                                    margin-bottom: 20px;
                                }
                                .text-block {
                                    background-color: #fff;
                                    padding: 15px;
                                    border-radius: 4px;
                                    border-left: 3px solid #546e7a;
                                    margin-bottom: 15px;
                                    color: #333;
                                }
                                .text-block p {
                                    margin: 8px 0;
                                    color: #333;
                                }
                                </style>
                                """, unsafe_allow_html=True)
                                
                                # Process and display content with images properly
                                import re

                                # Process each page separately
                                pages_content = []
                                
                                # Check if this is from a PDF processed through pdf2image
                                is_pdf2image = result.get('pdf_processing_method') == 'pdf2image'
                                
                                for i, page in enumerate(pages_data):
                                    page_markdown = page.get('markdown', '')
                                    images = page.get('images', [])
                                    
                                    if not page_markdown:
                                        continue
                                        
                                    # Create image dictionary
                                    image_dict = {}
                                    for img in images:
                                        if 'id' in img and 'image_base64' in img:
                                            image_dict[img['id']] = img['image_base64']
                                    
                                    # Create HTML content for this page
                                    page_html = f"<h3>Page {i+1}</h3>" if i > 0 else ""
                                    
                                    # Display the raw text content first to ensure it's visible
                                    page_html += f"<div class='page-text-content'>"
                                    
                                    # Special handling for PDF2image processed documents
                                    if is_pdf2image and i == 0 and 'ocr_contents' in result:
                                        # Display all structured content from OCR for PDFs
                                        page_html += "<div class='text-block pdf-content'>"
                                        
                                        # Check if custom prompt was applied
                                        if result.get('custom_prompt_applied') == 'text_only':
                                            page_html += "<div class='prompt-info'><i>Custom analysis applied using text-only processing</i></div>"
                                            
                                        ocr_contents = result.get('ocr_contents', {})
                                        # Get a sorted list of sections to ensure consistent order
                                        section_keys = sorted(ocr_contents.keys())
                                        
                                        # Place important sections first
                                        priority_sections = ['title', 'subtitle', 'header', 'publication', 'date', 'content', 'main_text']
                                        for important in priority_sections:
                                            if important in ocr_contents and important in section_keys:
                                                section_keys.remove(important)
                                                section_keys.insert(0, important)
                                                
                                        for section in section_keys:
                                            content = ocr_contents[section]
                                            if section in ['raw_text', 'error', 'partial_text']:
                                                continue  # Skip these fields
                                                
                                            section_title = section.replace('_', ' ').title()
                                            page_html += f"<h4>{section_title}</h4>"
                                            
                                            if isinstance(content, str):
                                                # Convert newlines to <br> tags
                                                content_html = content.replace('\n', '<br>')
                                                page_html += f"<p>{content_html}</p>"
                                            elif isinstance(content, list):
                                                page_html += "<ul>"
                                                for item in content:
                                                    if isinstance(item, str):
                                                        page_html += f"<li>{item}</li>"
                                                    elif isinstance(item, dict):
                                                        page_html += "<li>"
                                                        for k, v in item.items():
                                                            page_html += f"<strong>{k}:</strong> {v}<br>"
                                                        page_html += "</li>"
                                                    else:
                                                        page_html += f"<li>{str(item)}</li>"
                                                page_html += "</ul>"
                                            elif isinstance(content, dict):
                                                for k, v in content.items():
                                                    if isinstance(v, str):
                                                        page_html += f"<p><strong>{k}:</strong> {v}</p>"
                                                    elif isinstance(v, list):
                                                        page_html += f"<p><strong>{k}:</strong></p><ul>"
                                                        for item in v:
                                                            page_html += f"<li>{item}</li>"
                                                        page_html += "</ul>"
                                                    else:
                                                        page_html += f"<p><strong>{k}:</strong> {str(v)}</p>"
                                        
                                        page_html += "</div>"
                                    else:
                                        # Standard processing for regular documents
                                        # Get all text content that isn't an image and add it first
                                        text_content = []
                                        for line in page_markdown.split("\n"):
                                            if not re.search(r'!\[(.*?)\]\((.*?)\)', line) and line.strip():
                                                text_content.append(line)
                                        
                                        # Add the text content as a block
                                        if text_content:
                                            page_html += f"<div class='text-block'>"
                                            for line in text_content:
                                                page_html += f"<p>{line}</p>"
                                            page_html += "</div>"
                                    
                                    page_html += "</div>"
                                    
                                    # Then add images separately
                                    for line in page_markdown.split("\n"):
                                        # Handle image lines
                                        img_match = re.search(r'!\[(.*?)\]\((.*?)\)', line)
                                        if img_match:
                                            alt_text = img_match.group(1)
                                            img_ref = img_match.group(2)
                                            
                                            # Get the base64 data for this image ID
                                            img_data = image_dict.get(img_ref, "")
                                            if img_data:
                                                img_html = f'<div class="image-container"><img src="{img_data}" alt="{alt_text}"></div>'
                                                page_html += img_html
                                    
                                    # Add page separator if not the last page
                                    if i < len(pages_data) - 1:
                                        page_html += '<div class="page-break"></div>'
                                        
                                    pages_content.append(page_html)
                                
                                # Combine all pages HTML
                                html_content = "\n".join(pages_content)
                                
                                # Wrap the content in a div with the class for styling
                                st.markdown(f"""
                                <div class="markdown-text-container">
                                {html_content}
                                </div>
                                """, unsafe_allow_html=True)
                                
                                # Create download HTML content
                                download_html = f"""
                                <html>
                                <head>
                                    <style>
                                    body {{ 
                                        font-family: Georgia, serif; 
                                        line-height: 1.7; 
                                        margin: 0 auto;
                                        max-width: 800px;
                                        padding: 20px;
                                    }}
                                    img {{ 
                                        max-width: 90%; 
                                        max-height: 500px;
                                        object-fit: contain;
                                        margin: 20px auto; 
                                        display: block;
                                        border: 1px solid #ddd;
                                        border-radius: 4px;
                                    }}
                                    .image-container {{
                                        margin: 20px 0;
                                        text-align: center;
                                    }}
                                    .page-break {{
                                        border-top: 1px solid #ddd;
                                        margin: 40px 0;
                                        padding-top: 40px;
                                    }}
                                    h3 {{
                                        color: #333;
                                        border-bottom: 1px solid #eee;
                                        padding-bottom: 10px;
                                    }}
                                    p {{
                                        margin: 12px 0;
                                    }}
                                    .page-text-content {{
                                        margin-bottom: 20px;
                                    }}
                                    .text-block {{
                                        background-color: #f9f9f9;
                                        padding: 15px;
                                        border-radius: 4px;
                                        border-left: 3px solid #546e7a;
                                        margin-bottom: 15px;
                                        color: #333;
                                    }}
                                    .text-block p {{
                                        margin: 8px 0;
                                        color: #333;
                                    }}
                                    </style>
                                </head>
                                <body>
                                <div class="markdown-text-container">
                                {html_content}
                                </div>
                                </body>
                                </html>
                                """
                                
                                # Get original filename without extension
                                original_name = Path(result.get('file_name', uploaded_file.name)).stem
                                
                                # Add download button as an expander to prevent page reset
                                with st.expander("Download Document with Images"):
                                    st.markdown("Click the button below to download the document with embedded images")
                                    st.download_button(
                                        label="Download as HTML",
                                        data=download_html,
                                        file_name=f"{original_name}_with_images.html",
                                        mime="text/html",
                                        key="download_with_images_button"
                                    )
                                
                            except Exception as e:
                                st.error(f"Could not display document with images: {str(e)}")
                                st.info("Try refreshing or processing the document again.")
                
                    if 'ocr_contents' not in result:
                        st.error("No OCR content was extracted from the document.")
                        
                    # Close document content div
                    st.markdown('</div>', unsafe_allow_html=True)
                
                # Show a compact success message without extra container space
                metadata_placeholder.success("**Document processed successfully**")
                    
                # Store the result in the previous results list
                # Add timestamp to result for history tracking
                result_copy = result.copy()
                result_copy['timestamp'] = datetime.now().strftime("%Y-%m-%d %H:%M")
                
                # Add to session state, keeping the most recent 20 results
                st.session_state.previous_results.insert(0, result_copy)
                if len(st.session_state.previous_results) > 20:
                    st.session_state.previous_results = st.session_state.previous_results[:20]
                    
            except Exception as e:
                st.error(f"Error processing document: {str(e)}")
    else:
        # Empty placeholder - we've moved the upload instruction to the file_uploader
        
        # Show example images in a simpler layout
        st.subheader("Example Documents")
        
        # Add a simplified info message about examples
        st.markdown("""
        This app can process various historical documents:
        - Historical photographs, maps, and manuscripts
        - Handwritten letters and documents
        - Printed books and articles
        - Multi-page PDFs
        
        Upload your own document to get started or explore the 'About' tab for more information.
        """)
        
        # Display a direct message about sample documents
        st.info("Sample documents are available in the input directory. Upload a document to begin analysis.")# Minor update