using iText.Kernel.Pdf;
using iText.Kernel.Pdf.Canvas.Parser;
using iText.Kernel.Pdf.Canvas.Parser.Listener;
using iText.Kernel.Pdf.Xobject;
using OpenCvSharp;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Forms;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using Image = System.Drawing.Image;
using Path = System.IO.Path;
using Window = System.Windows.Window;

// see huggingface\ExtractPdfImage\ExportPdfImage\ExportPDFImage.xaml.cs

namespace WpfEditor
{
    /// <summary>
    /// Interaction logic for ExportPDFImage.xaml
    /// </summary>
    public partial class ExportPDFImage : Window
    {
        private string pdfFilePath = "";
        private string outputFolderPath = "";

        public ExportPDFImage()
        {
            InitializeComponent();
        }

        private void btnSelectPdf_Click(object sender, RoutedEventArgs e)
        {
            OpenFileDialog openFileDialog = new OpenFileDialog()
            {
                Filter = "PDF文件|*.pdf",
                Title = "选择PDF文件"
            };

            if (openFileDialog.ShowDialog() == System.Windows.Forms.DialogResult.OK)
            {
                pdfFilePath = openFileDialog.FileName;
                txtPdfPath.Text = pdfFilePath;
                lblStatus.Content = "状态：已选择PDF文件";
            }
        }

        private void btnSelectOutputFolder_Click(object sender, RoutedEventArgs e)
        {
            FolderBrowserDialog folderBrowserDialog = new FolderBrowserDialog()
            {
                Description = "选择图片输出文件夹"
            };

            if (folderBrowserDialog.ShowDialog() == System.Windows.Forms.DialogResult.OK)
            {
                outputFolderPath = folderBrowserDialog.SelectedPath;
                txtOutputPath.Text = outputFolderPath;
                lblStatus.Content = "状态：已选择输出文件夹";
            }
        }

        private async void btnExtractImages_Click(object sender, RoutedEventArgs e)
        {
            if (string.IsNullOrEmpty(pdfFilePath))
            {
                System.Windows.MessageBox.Show("请先选择PDF文件！", "提示", MessageBoxButton.OK, MessageBoxImage.Warning);
                return;
            }

            if (string.IsNullOrEmpty(outputFolderPath))
            {
                System.Windows.MessageBox.Show("请先选择输出文件夹！", "提示", MessageBoxButton.OK, MessageBoxImage.Warning);
                return;
            }

            btnExtractImages.IsEnabled = false;
            listBoxImages.Items.Clear();
            progressBar.Value = 0;
            lblStatus.Content = "状态：正在提取图片...";

            try
            {
                await Task.Run(() => ExtractImagesFromPdf());
                lblStatus.Content = "状态：图片提取完成！";
                System.Windows.MessageBox.Show("图片提取完成！", "成功", MessageBoxButton.OK, MessageBoxImage.Information);
            }
            catch (Exception ex)
            {
                lblStatus.Content = "状态：提取失败";
                System.Windows.MessageBox.Show($"提取图片时发生错误：{ex.Message}", "错误", MessageBoxButton.OK, MessageBoxImage.Error);
            }
            finally
            {
                btnExtractImages.IsEnabled = true;
                progressBar.Value = 0;
            }
        }

        private void ExtractImagesFromPdf()
        {
            using (PdfReader reader = new PdfReader(pdfFilePath))
            using (PdfDocument pdfDoc = new PdfDocument(reader))
            {
                int totalPages = pdfDoc.GetNumberOfPages();
                int imageCount = 0;

                for (int pageNumber = 1; pageNumber <= totalPages; pageNumber++)
                {
                    Dispatcher.Invoke(() =>
                    {
                        progressBar.Value = (int)((double)pageNumber / totalPages * 100);
                        lblStatus.Content = $"状态：正在处理第 {pageNumber}/{totalPages} 页...";
                    });

                    PdfPage page = pdfDoc.GetPage(pageNumber);
                    PdfDictionary pageDict = page.GetPdfObject();
                    PdfDictionary resources = pageDict.GetAsDictionary(PdfName.Resources);

                    if (resources != null)
                    {
                        PdfDictionary xObjects = resources.GetAsDictionary(PdfName.XObject);
                        if (xObjects != null)
                        {
                            foreach (PdfName name in xObjects.KeySet())
                            {
                                PdfObject obj = xObjects.Get(name);
                                if (obj.IsStream())
                                {
                                    PdfStream stream = (PdfStream)obj;
                                    PdfObject subtype = stream.Get(PdfName.Subtype);

                                    if (subtype != null && subtype.Equals(PdfName.Image))
                                    {
                                        try
                                        {
                                            imageCount++;
                                            string imageName = $"{pageNumber:D4}";
                                            string imagePath = Path.Combine(outputFolderPath, imageName);

                                            ExtractImage(stream, imagePath);

                                            Dispatcher.Invoke(() =>
                                            {
                                                listBoxImages.Items.Add($"已提取：{imageName}");
                                            });
                                        }
                                        catch (Exception ex)
                                        {
                                            Dispatcher.Invoke(() =>
                                            {
                                                listBoxImages.Items.Add($"提取失败：第{pageNumber}页图片 - {ex.Message}");
                                            });
                                        }
                                    }
                                }
                            }
                        }
                    }
                }

                Dispatcher.Invoke(() =>
                {
                    lblStatus.Content = $"状态：完成！共提取 {imageCount} 张图片";
                });
            }
        }

        private void ExtractImage(PdfStream stream, string imagePath)
        {
            byte[] bts = stream.GetBytes();
            Mat img = Cv2.ImDecode(bts, ImreadModes.Color);
            Cv2.ImWrite(imagePath + ".jpg", img);
            return;

            PdfObject filter = stream.Get(PdfName.Filter);

            if (filter != null)
            {
                if (filter.Equals(PdfName.DCTDecode)) // JPEG
                {
                    File.WriteAllBytes(imagePath + ".jpg", stream.GetBytes());
                }
                else if (filter.Equals(PdfName.JPXDecode)) // JPEG2000
                {
                    File.WriteAllBytes(imagePath + ".jp2", stream.GetBytes());
                }
                else
                {

                }
            }
            else
            {
                File.WriteAllBytes(imagePath + ".raw", stream.GetBytes());
            }
        }
    }
}