using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using DevExtreme.AspNet.Mvc.FileManagement;
using PdfiumViewer;

namespace PdfThumbnailExtractor
{
    public class PdfThumbnailService
    {
        public static string GenerateThumbnail(FileSystemLoadFile file)
        {
            // Ensure the uploaded file is a PDF
            if (!file.Name.EndsWith(".pdf", StringComparison.OrdinalIgnoreCase))
            {
                throw new InvalidOperationException("Only PDF files are supported.");
            }

            // Load the PDF file
            using (var pdfStream = new MemoryStream(file.Content))
            using (var pdfDocument = PdfDocument.Load(pdfStream))
            {
                // Render the first page as an image
                var image = pdfDocument.Render(0, 200, 200, true);

                // Save the thumbnail to a temporary file
                var thumbnailPath = Path.Combine(Path.GetTempPath(), $"{Path.GetFileNameWithoutExtension(file.Name)}_thumbnail.png");
                image.Save(thumbnailPath, ImageFormat.Png);

                return thumbnailPath;
            }
        }
    }
}

/*
using DevExpress.Pdf;
using DevExpress.Drawing;

using (PdfDocumentProcessor processor = new PdfDocumentProcessor()) {
    processor.LoadDocument("uploaded.pdf");
    DXBitmap bitmap = processor.CreateBitmap(0); // First page
    bitmap.Save("thumbnail.png");
}

*/