package com.bcxin.backend.utils;

import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.rendering.ImageType;
import org.apache.pdfbox.rendering.PDFRenderer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.nio.file.Path;
import java.nio.file.Paths;

public class DocumentFileUtil {
    private static final Logger logger = LoggerFactory.getLogger(DocumentFileUtil.class);
    // 添加最小印章像素阈值（例如：50x50 像素）
    private static final int MIN_SEAL_PIXELS = 50 * 50;

    public static boolean checkPdfForRedSeal(
            String rootPath,
            String filePath) {
        try {
            Path pdfPath = Paths.get(rootPath + filePath);
            File file = pdfPath.toFile();

            if (!file.exists()) {
                logger.error("文件不存在: {}", pdfPath);
                return false;
            }

            try (PDDocument document = PDDocument.load(file)) {
                PDFRenderer pdfRenderer = new PDFRenderer(document);
                BufferedImage image = pdfRenderer.renderImageWithDPI(0, 300, ImageType.RGB);

                int width = image.getWidth();
                int height = image.getHeight();

                // 使用二维数组记录已访问的像素点
                boolean[][] visited = new boolean[height][width];
                int minSealDetected = 0;

                for (int y = 0; y < height; y++) {
                    for (int x = 0; x < width; x++) {
                        if (visited[y][x]) continue;

                        int rgb = image.getRGB(x, y);
                        int r = (rgb >> 16) & 0xFF;
                        int g = (rgb >> 8) & 0xFF;
                        int b = rgb & 0xFF;

                        // 判断是否为红色像素
                        if (r > 150 && g < 100 && b < 100) {
                            // 使用广度优先搜索查找连通区域
                            int areaSize = floodFill(image, x, y, visited, width, height);
                            if (areaSize > MIN_SEAL_PIXELS) {
                                logger.info("发现疑似红色印章，面积：{}", areaSize);
                                minSealDetected++;
                            }
                        }
                    }
                }

                return minSealDetected > 0;

            } catch (IOException e) {
                logger.error("读取PDF文件失败: {}", filePath, e);
            }
        } catch (Exception ex) {
            logger.error("checkPdfForRedSeal: 执行失败:filePath={}", filePath, ex);
        }

        return false;
    }

    private static int floodFill(BufferedImage image, int startX, int startY, boolean[][] visited, int width, int height) {
        int count = 0;
        java.util.Queue<int[]> queue = new java.util.LinkedList<>();
        queue.add(new int[]{startX, startY});
        visited[startY][startX] = true;

        while (!queue.isEmpty()) {
            int[] point = queue.poll();
            int x = point[0];
            int y = point[1];

            count++;

            // 检查上下左右四个方向
            for (int dx = -1; dx <= 1; dx++) {
                for (int dy = -1; dy <= 1; dy++) {
                    if (dx == 0 && dy == 0) continue;
                    int nx = x + dx;
                    int ny = y + dy;

                    if (nx >= 0 && nx < width && ny >= 0 && ny < height && !visited[ny][nx]) {
                        int rgb = image.getRGB(nx, ny);
                        int r = (rgb >> 16) & 0xFF;
                        int g = (rgb >> 8) & 0xFF;
                        int b = rgb & 0xFF;

                        if (r > 150 && g < 100 && b < 100) {
                            visited[ny][nx] = true;
                            queue.add(new int[]{nx, ny});
                        }
                    }
                }
            }
        }

        return count;
    }
}