package com.xindao.ocr.swingui.swing.jpanel;

import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.rendering.PDFRenderer;

import javax.swing.*;
import java.awt.*;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;
import java.awt.geom.AffineTransform;
import java.awt.geom.Rectangle2D;
import java.awt.image.BufferedImage;
import java.io.IOException;

public class PdfPreviewPanel extends JPanel {
        private PDDocument document;
        private int pageNumber;
        private BufferedImage pageImage;
        private Rectangle2D selection = null;
        private Rectangle2D lastSelection = null; // 上次选择的区域
        private Point startDrag = null;
        private float scale = 1.0f;
        private Point translation = new Point(0, 0); // 平移量
        private Point lastDragPoint = null;
        private float pdfWidth;
        private float pdfHeight;
        private boolean isDraggingPage = false; // 是否正在拖拽页面

        private static final Color SELECTION_COLOR = new Color(255, 193, 7, 100); // 半透明黄色
        private static final Color LAST_SELECTION_COLOR = new Color(76, 175, 80, 100); // 半透明绿色，用于标识上次选择的区域

        public PdfPreviewPanel(PDDocument doc, int pageNum, Rectangle2D lastArea) throws IOException {
            this.document = doc;
            this.pageNumber = pageNum;
            this.lastSelection = lastArea;

            // 渲染PDF页面为图片
            PDFRenderer renderer = new PDFRenderer(doc);
            pageImage = renderer.renderImage(pageNumber);

            // 获取PDF页面尺寸
            pdfWidth = pageImage.getWidth();
            pdfHeight = pageImage.getHeight();

            // 如果有上次选择的区域，默认选中
            if (lastSelection != null) {
                this.selection = lastSelection;
            }

            // 添加鼠标监听器处理选择和拖拽
            addMouseListener(new MouseAdapter() {
                @Override
                public void mousePressed(MouseEvent e) {
                    // 检查点击位置是否在PDF页面上
                    Rectangle2D pageBounds = getPageBounds();
                    if (pageBounds.contains(e.getPoint())) {
                        // 检查是否点击在选择区域内
                        if (selection != null && selection.contains(e.getPoint())) {
                            startDrag = e.getPoint();
                            isDraggingPage = false;
                        } else {
                            // 开始新的选择
                            startDrag = e.getPoint();
                            selection = null;
                            isDraggingPage = false;
                        }
                    } else {
                        // 点击在页面外，准备拖拽整个页面
                        lastDragPoint = e.getPoint();
                        isDraggingPage = true;
                    }
                    repaint();
                }

                @Override
                public void mouseReleased(MouseEvent e) {
                    startDrag = null;
                    lastDragPoint = null;
                    isDraggingPage = false;
                    repaint();
                }
            });

            addMouseMotionListener(new MouseMotionAdapter() {
                @Override
                public void mouseDragged(MouseEvent e) {
                    if (isDraggingPage && lastDragPoint != null) {
                        // 拖拽整个页面
                        int dx = e.getX() - lastDragPoint.x;
                        int dy = e.getY() - lastDragPoint.y;
                        translation.x += dx;
                        translation.y += dy;
                        lastDragPoint = e.getPoint();
                        repaint();
                    } else if (startDrag != null) {
                        // 拖拽选择区域
                        Point endDrag = e.getPoint();
                        selection = createRectangle(startDrag, endDrag);
                        repaint();
                    }
                }
            });

            // 设置面板首选大小
            setPreferredSize(new Dimension(pageImage.getWidth(), pageImage.getHeight()));
        }

        // 获取PDF页面在面板中的边界
        private Rectangle2D getPageBounds() {
            return new Rectangle2D.Double(
                translation.getX(),
                translation.getY(),
                pageImage.getWidth() * scale,
                pageImage.getHeight() * scale
            );
        }

        private Rectangle2D createRectangle(Point p1, Point p2) {
            int x = Math.min(p1.x, p2.x);
            int y = Math.min(p1.y, p2.y);
            int width = Math.abs(p1.x - p2.x);
            int height = Math.abs(p1.y - p2.y);
            return new Rectangle2D.Double(x, y, width, height);
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            Graphics2D g2 = (Graphics2D) g;
            g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
            g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);

            // 绘制背景
            g2.setColor(new Color(240, 240, 240));
            g2.fillRect(0, 0, getWidth(), getHeight());

            // 绘制PDF页面
            if (pageImage != null) {
                // 保存当前变换
                AffineTransform originalTransform = g2.getTransform();

                // 应用平移和缩放
                g2.translate(translation.x, translation.y);
                g2.scale(scale, scale);

                // 绘制PDF图像
                g2.drawImage(pageImage, 0, 0, null);

                // 绘制上次选择的区域（如果有）
                if (lastSelection != null && (selection == null || !selection.equals(lastSelection))) {
                    g2.setColor(LAST_SELECTION_COLOR);
                    g2.fill(lastSelection);
                    g2.setColor(new Color(76, 175, 80));
                    g2.setStroke(new BasicStroke(1));
                    g2.draw(lastSelection);
                }

                // 绘制当前选择区域
                if (selection != null) {
                    // 转换选择区域坐标到PDF坐标系统
                    Rectangle2D pdfSelection = new Rectangle2D.Double(
                        selection.getX() - translation.x,
                        selection.getY() - translation.y,
                        selection.getWidth(),
                        selection.getHeight()
                    );
                    pdfSelection = new Rectangle2D.Double(
                        pdfSelection.getX() / scale,
                        pdfSelection.getY() / scale,
                        pdfSelection.getWidth() / scale,
                        pdfSelection.getHeight() / scale
                    );

                    g2.setColor(SELECTION_COLOR);
                    g2.fill(pdfSelection);
                    g2.setColor(Color.ORANGE);
                    g2.setStroke(new BasicStroke(2));
                    g2.draw(pdfSelection);
                }

                // 恢复变换
                g2.setTransform(originalTransform);
            }
        }

        public Rectangle2D getSelection() {
            return selection;
        }

        public float getScale() {
            return scale;
        }

        public Point getTranslation() {
            return translation;
        }

        public float getPdfHeight() {
            return pdfHeight;
        }
    }