package cn.lili.common.utils;

import lombok.extern.slf4j.Slf4j;
import org.springframework.web.multipart.MultipartFile;

import java.io.*;
import java.util.Base64;
import java.util.Base64.Decoder;

/**
 * base64转为multipartFile工具类
 *
 * @author Chopper
 */
@Slf4j
public class Base64DecodeMultipartFile implements MultipartFile {

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

    public Base64DecodeMultipartFile(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() + (int) Math.random() * 10000 + "." + header.split("/")[1];
    }

    @Override
    public String getContentType() {
        return header.split(":")[1];
    }

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

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

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

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

    @Override
    public void transferTo(File dest) throws IOException, IllegalStateException {
        OutputStream stream = null;
        try {
            stream = new FileOutputStream(dest);
            stream.write(imgContent);
        } catch (IOException e) {
            log.error("transferTo错误", e);
        } finally {
            assert stream != null;
            stream.close();
        }
    }


    public static MultipartFile base64Convert(String base64) {

        String[] baseStrs = base64.split(",");
        Decoder decoder = Base64.getDecoder();
        byte[] b = decoder.decode(baseStrs[1]);

        for (int i = 0; i < b.length; ++i) {
            if (b[i] < 0) {
                b[i] += 256;
            }
        }
        return new Base64DecodeMultipartFile(b, baseStrs[0]);
    }


    public static InputStream base64ToInputStream(String base64) {
        ByteArrayInputStream stream = null;
        try {
            byte[] bytes = Base64.getDecoder().decode(base64);
            stream = new ByteArrayInputStream(bytes);
        } catch (Exception e) {
            log.error("base64ToInputStream错误", e);
        }
        return stream;
    }

    public static String inputStreamToStream(InputStream in) {
        byte[] data = null;
        //读取图片字节数组
        try {
            ByteArrayOutputStream swapStream = new ByteArrayOutputStream();
            byte[] buff = new byte[100];
            int rc = 0;
            while ((rc = in.read(buff, 0, 100)) > 0) {
                swapStream.write(buff, 0, rc);
            }
            data = swapStream.toByteArray();
        } catch (IOException e) {
            log.error("转码错误", e);
        } finally {
            if (in != null) {
                try {
                    in.close();
                } catch (IOException e) {
                    log.error("inputStreamToStream错误", e);
                }
            }
        }
        return Base64.getEncoder().encodeToString(data);
    }
}