package com.ycwl.basic.utils;

import cn.hutool.core.codec.Base64;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.multipart.MultipartFile;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;

@Slf4j
public class ImageUtils {
    public static MultipartFile base64ToMultipartFile(String base64) {
        String[] baseStrs = base64.split(",");
        byte[] b;
        b = Base64.decode(baseStrs[0]);
        for (int i = 0; i < b.length; ++i) {
            if (b[i] < 0) {
                b[i] += (byte) 256;
            }
        }
        return new Base64DecodedMultipartFile(b, baseStrs[0]);
    }

    public static MultipartFile cropImage(MultipartFile file, int x, int y, int w, int h) throws IOException {
        BufferedImage image = null;
        BufferedImage targetImage = null;
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        try {
            image = ImageIO.read(file.getInputStream());
            log.info("图片宽高：{}", image.getWidth() + "x" + image.getHeight());
            log.info("图片裁切：{}@{}", w + "x" + h, x + "," + y);
            if (image.getWidth() < w) {
                w = image.getWidth();
            }
            if (image.getHeight() < h) {
                h = image.getHeight();
            }
            int targetX = x;
            if (x < 0) {
                targetX = 0;
            } else if ((x + w) > image.getWidth()) {
                targetX = image.getWidth() - w;
            }
            int targetY = y;
            if (y < 0) {
                targetY = 0;
            } else if ((y + h) > image.getHeight()) {
                targetY = image.getHeight() - h;
            }
            log.info("图片实际裁切：{}@{}", w + "x" + h, targetX + "," + targetY);
            targetImage = image.getSubimage(targetX, targetY, w, h);
            ImageIO.write(targetImage, "jpg", baos);
            return new Base64DecodedMultipartFile(baos.toByteArray(), "image/jpeg");
        } finally {
            // 修复内存泄漏：显式释放图片资源
            if (image != null) {
                image.flush();
                image = null;
            }
            if (targetImage != null) {
                targetImage.flush();
                targetImage = null;
            }
            try {
                baos.close();
            } catch (IOException e) {
                log.warn("关闭ByteArrayOutputStream失败", e);
            }
            // 建议JVM进行垃圾回收
            System.gc();
        }
    }

    public static class Base64DecodedMultipartFile implements MultipartFile {

        private final byte[] imgContent;
        private final String header;

        public Base64DecodedMultipartFile(byte[] imgContent, String header) {
            this.imgContent = imgContent;
            this.header = header.split(";")[0];
        }

        @Override
        public String getName() {
            return System.currentTimeMillis() + Math.random() + "." + header.split("/")[1];
        }

        @Override
        public String getOriginalFilename() {
            return System.currentTimeMillis() + "." + header.split("/")[1];
        }

        @Override
        public String getContentType() {
            return "";
        }

        @Override
        public boolean isEmpty() {
            return imgContent == null || imgContent.length == 0;
        }

        @Override
        public long getSize() {
            return imgContent.length;
        }

        @Override
        public byte[] getBytes() {
            return imgContent;
        }

        @Override
        public InputStream getInputStream() {
            return new ByteArrayInputStream(imgContent);
        }

        @Override
        public void transferTo(File dest) throws IOException, IllegalStateException {
            new FileOutputStream(dest).write(imgContent);
        }

    }

}