import gradio as gr
import os
from pdf2image import convert_from_path
from pathlib import Path
import uuid

def pdf_to_jpeg(pdf_file, dpi, quality):
    """
    Converts a PDF file into a list of high-resolution JPEG images.
    
    Args:
        pdf_file (str): Path to the uploaded PDF file.
        dpi (int): Dots per inch for resolution.
        quality (int): JPEG quality (1-100).
        
    Returns:
        list: List of paths to the generated JPEG files.
    """
    if pdf_file is None:
        raise gr.Error("Please upload a PDF file first.")

    try:
        # Create a unique directory for this session's output to avoid collisions
        session_id = str(uuid.uuid4())
        output_dir = Path(f"outputs/{session_id}")
        output_dir.mkdir(parents=True, exist_ok=True)

        # Convert PDF to images
        # dpi=300 is generally considered high resolution for printing/viewing
        images = convert_from_path(pdf_file, dpi=dpi)
        
        jpeg_paths = []
        for i, image in enumerate(images):
            # Generate filename: page_1.jpg, page_2.jpg...
            file_path = output_dir / f"page_{i+1}.jpg"
            # Save as JPEG with specified quality
            image.save(file_path, "JPEG", quality=quality)
            jpeg_paths.append(str(file_path))

        return jpeg_paths

    except Exception as e:
        raise gr.Error(f"An error occurred during conversion: {str(e)}")

# Custom professional theme for Gradio 6
custom_theme = gr.themes.Soft(
    primary_hue="indigo",
    secondary_hue="slate",
    neutral_hue="gray",
    font=gr.themes.GoogleFont("Inter"),
    spacing_size="lg",
    radius_size="md"
).set(
    button_primary_background_fill="*primary_600",
    button_primary_background_fill_hover="*primary_700",
)

with gr.Blocks() as demo:
    # Header section
    gr.Markdown(
        """
        # 📄 PDF to High-Res JPEG Converter
        Convert your PDF documents into professional, high-resolution JPEG images. 
        Each page of your PDF will be processed as a separate high-quality image slice.
        
        ***
        [Built with anycoder](https://huggingface.co/spaces/akhaliq/anycoder)
        """
    )
    
    with gr.Row():
        with gr.Column(scale=1):
            gr.Markdown("### ⚙️ Conversion Settings")
            pdf_input = gr.File(
                label="Upload PDF", 
                file_types=[".pdf"], 
                file_count="single"
            )
            
            with gr.Group():
                dpi_slider = gr.Slider(
                    minimum=72, 
                    maximum=600, 
                    value=300, 
                    step=1, 
                    label="Resolution (DPI)", 
                    info="300 DPI is standard for high quality. 600 DPI is ultra-high."
                )
                quality_slider = gr.Slider(
                    minimum=1, 
                    maximum=100, 
                    value=95, 
                    step=1, 
                    label="JPEG Quality", 
                    info="Higher value means better quality but larger file size."
                )
            
            convert_btn = gr.Button("Convert to JPEG", variant="primary", size="lg")
            clear_btn = gr.Button("Clear All", variant="secondary")

        with gr.Column(scale=2):
            gr.Markdown("### 🖼️ Generated Images")
            # Gallery is perfect for showing multiple slices of the PDF
            output_gallery = gr.Gallery(
                label="Processed Pages", 
                show_label=False, 
                columns=2, 
                object_fit="contain", 
                height="auto"
            )

    # Event Listeners
    convert_btn.click(
        fn=pdf_to_jpeg,
        inputs=[pdf_input, dpi_slider, quality_slider],
        outputs=[output_gallery],
        api_visibility="public"
    )
    
    clear_btn.click(
        fn=lambda: (None, None),
        inputs=None,
        outputs=[pdf_input, output_gallery],
        api_visibility="public"
    )

# Gradio 6 Launch Configuration
demo.launch(
    theme=custom_theme,
    footer_links=[
        {"label": "Built with anycoder", "url": "https://huggingface.co/spaces/akhaliq/anycoder"}
    ]
)