import com.google.zxing.BarcodeFormat;
import com.google.zxing.BinaryBitmap;
import com.google.zxing.DecodeHintType;
import com.google.zxing.LuminanceSource;
import com.google.zxing.MultiFormatReader;
import com.google.zxing.NotFoundException;
import com.google.zxing.Result;
import com.google.zxing.client.j2se.BufferedImageLuminanceSource;
import com.google.zxing.common.GlobalHistogramBinarizer;
import com.google.zxing.common.HybridBinarizer;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.File;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.EnumMap;
import java.util.List;
import java.util.Map;

/**
 * 二维码标签解码校验
 *
 * 用法：java DecodeQr <标签目录>
 *
 * 对每张标签分别用「整图」和「裁到二维码区域」两种方式解码：
 * 整图失败而裁图成功，说明标签本身没坏，是下方文字干扰了检测器，属解码端问题；
 * 两种方式都失败，才是标签真的不可识读。
 */
public class DecodeQr {

    /** 标签排版参数，须与 QrCodeImageUtils 保持一致 */
    private static final int PADDING = 16;
    private static final int QR_SIZE = 260;
    /** 裁图时向外多留的余量，保证二维码静区不被切掉 */
    private static final int CROP_MARGIN = 10;

    public static void main(String[] args) throws Exception {
        if (args.length == 0) {
            System.out.println("用法: java DecodeQr <标签目录>");
            return;
        }
        File dir = new File(args[0]);
        File[] files = dir.listFiles((d, n) -> n.toLowerCase().endsWith(".png"));
        if (files == null || files.length == 0) {
            System.out.println("目录内没有 PNG 文件：" + dir.getAbsolutePath());
            return;
        }
        Arrays.sort(files);

        int fullOk = 0;
        int cropOk = 0;
        int bothFail = 0;
        List<String> fullFailCropOk = new ArrayList<>();
        List<String> hardFail = new ArrayList<>();
        List<String> mismatched = new ArrayList<>();
        String sampleContent = null;

        for (File f : files) {
            String name = f.getName();
            String code = name.endsWith(".png") ? name.substring(0, name.length() - 4) : name;
            BufferedImage image = ImageIO.read(f);
            if (image == null) {
                hardFail.add(name + " -> 图片无法读取");
                bothFail++;
                continue;
            }
            String full = decode(image);
            String crop = decode(cropQrArea(image));
            if (full != null) {
                fullOk++;
            }
            if (crop != null) {
                cropOk++;
            }
            if (full == null && crop == null) {
                bothFail++;
                hardFail.add(name + " -> 整图与裁图均解码失败");
                continue;
            }
            if (full == null) {
                fullFailCropOk.add(name);
            }
            String text = full != null ? full : crop;
            if (!text.contains(code)) {
                mismatched.add(name + " -> 内容与码值不符: " + text);
            }
            if (sampleContent == null) {
                sampleContent = "码值 " + code + "\n        二维码内容 " + text;
            }
        }

        int total = files.length;
        System.out.println("标签总数        : " + total);
        System.out.printf ("整图解码成功    : %d (%.2f%%)%n", fullOk, fullOk * 100.0 / total);
        System.out.printf ("裁图解码成功    : %d (%.2f%%)%n", cropOk, cropOk * 100.0 / total);
        System.out.printf ("两种方式都失败  : %d (%.2f%%)%n", bothFail, bothFail * 100.0 / total);
        System.out.println("整图失败但裁图成功（检测受下方文字干扰，标签本身正常）: " + fullFailCropOk.size());
        System.out.println("\n--- 样本 ---\n         " + sampleContent);

        if (!fullFailCropOk.isEmpty()) {
            System.out.println("\n--- 仅整图失败的码（前 10） ---");
            fullFailCropOk.stream().limit(10).forEach(s -> System.out.println("  " + s));
        }
        if (!mismatched.isEmpty()) {
            System.out.println("\n!!! 内容与码值不符（前 10） !!!");
            mismatched.stream().limit(10).forEach(s -> System.out.println("  " + s));
        }
        if (!hardFail.isEmpty()) {
            System.out.println("\n--- 真正不可识读的标签（前 20） ---");
            hardFail.stream().limit(20).forEach(s -> System.out.println("  " + s));
        }
    }

    /** 裁出二维码所在区域，去掉下方叠加的文字 */
    private static BufferedImage cropQrArea(BufferedImage src) {
        int x = Math.max(0, PADDING - CROP_MARGIN);
        int y = Math.max(0, PADDING - CROP_MARGIN);
        int w = Math.min(src.getWidth() - x, QR_SIZE + CROP_MARGIN * 2);
        int h = Math.min(src.getHeight() - y, QR_SIZE + CROP_MARGIN * 2);
        return src.getSubimage(x, y, w, h);
    }

    /** 尝试多种二值化策略解码，全部失败返回 null */
    private static String decode(BufferedImage image) {
        LuminanceSource source = new BufferedImageLuminanceSource(image);
        Map<DecodeHintType, Object> hints = new EnumMap<>(DecodeHintType.class);
        hints.put(DecodeHintType.CHARACTER_SET, "UTF-8");
        hints.put(DecodeHintType.TRY_HARDER, Boolean.TRUE);
        hints.put(DecodeHintType.POSSIBLE_FORMATS, List.of(BarcodeFormat.QR_CODE));
        // HybridBinarizer 适合光照不均，GlobalHistogramBinarizer 对高对比度图更稳，两者互补
        for (var binarizer : List.of(new HybridBinarizer(source), new GlobalHistogramBinarizer(source))) {
            try {
                Result r = new MultiFormatReader().decode(new BinaryBitmap(binarizer), hints);
                if (r != null && r.getText() != null) {
                    return r.getText();
                }
            } catch (NotFoundException ignored) {
                // 换下一种策略
            } catch (Exception ignored) {
                // 同上
            }
        }
        return null;
    }
}