using PdfiumViewer;
using System.Drawing.Imaging;
using System.Drawing;
using System;
using System.Linq;
using System.Threading.Tasks;
using System.IO;
using System.Collections.Generic;

namespace Shentun.Utilities
{
    public class PdfiumConverter
    {
        public static List<string> ConvertPdfToImages(string pdfBase64)
        {
            List<string> base64Images = new List<string>();
            //try
            //{

            if (pdfBase64.Contains("base64,"))
            {
                pdfBase64 = pdfBase64.Substring(pdfBase64.IndexOf(",") + 1);
            }
            // 将Base64字符串转换为字节数组
            byte[] pdfBytes = Convert.FromBase64String(pdfBase64);
            Stream pdfStream = new MemoryStream(pdfBytes);

            using var document = PdfDocument.Load(pdfStream);

            for (int i = 0; i < document.PageCount; i++)
            {
                // 将页面转换为图片
                using (Image image = document.Render(i, 600, 600, true))
                {
                    // 将图片转换为Base64字符串
                    string base64 = ImageToBase64(image, ImageFormat.Jpeg);
                    base64Images.Add(base64);
                }
            }

            //}
            //catch (Exception ex)
            //{

            //}

            return base64Images;
        }

        private static string ImageToBase64(Image image, ImageFormat format)
        {
            using (MemoryStream ms = new MemoryStream())
            {
                image.Save(ms, format);
                byte[] imageBytes = ms.ToArray();
                return Convert.ToBase64String(imageBytes);
            }
        }
    }
}