package edu.travel.upload.obs;

import com.obs.services.ObsClient;
import com.obs.services.exception.ObsException;
import com.obs.services.internal.ServiceException;
import com.obs.services.model.*;
import edu.travel.upload.obs.property.ObsProperties;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.stereotype.Component;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Base64;
import java.util.Optional;

@Component
@ConditionalOnClass(ObsClient.class)
public class HuaweiOBSUtils {
    Logger log = LoggerFactory.getLogger(HuaweiOBSUtils.class);
    @Autowired
    private ObsClient obsClient;
    @Autowired
    private ObsProperties obsProperties;
    //注意这里传进来的参数是处理后的图片 base64 参数，处理方法只需要调用 api,这里不做过多解释，可以上网查询转换方法，另外是指定的文件名称和bucket名称，上传后的文件将是以该 fileName 存在于该bucket 内
    //此方法是用于上传文件，内部调用了 obs 的含有 MD5 参数校验的api方法
    public void uploadPic(String base64, String fileName) {
        byte[] bytes = Base64.getDecoder().decode(base64);
        ObjectMetadata meta = new ObjectMetadata();
        // 设置MD5校验。
        String md5 = toBase64String(calculateMd5(bytes));
        meta.setContentMd5(md5);
        try (InputStream inputStream = new ByteArrayInputStream(bytes)) {
            PutObjectResult result = obsClient.putObject(obsProperties.getBucketName(), fileName, inputStream,meta);
        } catch (Exception e) {
            log.error("Upload failed: ", e);
        }
    }

    // 计算 MD5 值的方法
    private static byte[] calculateMd5(byte[] data) {
        try {
            MessageDigest md = MessageDigest.getInstance("MD5");
            return md.digest(data);
        } catch (NoSuchAlgorithmException e) {
            throw new RuntimeException("MD5 algorithm not found.", e);
        }
    }

    // 将字节数组转换为 Base64 编码的字符串
    private static String toBase64String(byte[] bytes) {
        return Base64.getEncoder().encodeToString(bytes);
    }

    //该方法是用于检查bucket 内是否有指定文件，内部调用了 obs 的获取文件方法
    public Boolean checkExist(String fileName,String bucketName) {
        ObsObject object = null;
        InputStream inputStream = null;
        try {
            object = obsClient.getObject(bucketName, fileName);
            inputStream = object.getObjectContent();
            if (inputStream != null) {
                return true;
            }
        } catch (Exception e) {
            log.error("请求异常:{}", fileName, e);
            return false;
        } finally {
            // 确保关闭 InputStream
            try {
                if (inputStream != null) {
                    inputStream.close();
                }
            } catch (IOException e) {
                log.error("关闭 InputStream 异常", e);
            }
        }
        return false;
    }


    //该方法是用于获取指定时间内的文件下载链接
    public String getPicViewUrlByInternal(String fileName) {
        Boolean aBoolean = checkExist(fileName,obsProperties.getBucketName());
        if (!aBoolean) {
            return null;
        }
        // 生成以GET方法访问的签名URL，访客可以直接通过浏览器访问相关内容。
        String url = generatePresignedUrl(obsProperties.getExpiration(), fileName,obsProperties.getBucketName());
        return url;
    }

    private  String generatePresignedUrl(Long expire,String fileName,String bucketName) {
        TemporarySignatureResponse response = null;
        try {
            // URL有效期，3600秒
            //long expireSeconds = 3600L;
            TemporarySignatureRequest request = new TemporarySignatureRequest(HttpMethodEnum.GET, expire);
            request.setBucketName(bucketName);
            request.setObjectKey(fileName);
            response = obsClient.createTemporarySignature(request);
        } catch (ObsException e) {
            log.error("get obs failed :{}", e.getMessage());
            throw new ServiceException(e.getMessage());
        }
        return Optional.ofNullable(response)
                .map(TemporarySignatureResponse::getSignedUrl)
                .orElse(null);
    }

}