PAS/src/main/java/cn/cslg/pas/service/business/PDFExportFirstPageService.java

package cn.cslg.pas.service.business;

import cn.cslg.pas.common.dto.PatentColumnDTO;
import cn.cslg.pas.common.dto.PatentDTO;
import cn.cslg.pas.common.model.request.QueryRequest;
import cn.cslg.pas.common.utils.FormatUtil;
import cn.cslg.pas.exception.XiaoShiException;
import cn.cslg.pas.service.business.es.EsService;
import cn.cslg.pas.service.common.FileManagerService;
import lombok.extern.slf4j.Slf4j;
import org.apache.pdfbox.multipdf.PDFMergerUtility;
import org.apache.pdfbox.io.MemoryUsageSetting;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDPage;
import org.apache.pdfbox.rendering.PDFRenderer;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.io.ByteArrayOutputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

/**
 * @Author xiexiang
 * @Date 2024/1/4
 */
@Slf4j
@Service
public class PDFExportFirstPageService {
    @Autowired
    private FileManagerService fileManagerService;
    @Autowired
    private EsService esService;

    /**
     * 1
     * @param projectId
     * @return
     * @throws IOException
     */
    public byte[] mergeAndExportPDFFirstPage(Integer projectId) throws IOException {
        //根据projectId查询专利信息
        QueryRequest queryRequest = new QueryRequest();
        queryRequest.setProjectId(projectId);
        PatentDTO patentDTO;
        try {
            patentDTO = esService.esSearch(queryRequest);
        } catch (Exception e) {
            throw new XiaoShiException("检索专利错误");
        }
        List<PatentColumnDTO> patents = patentDTO.getPatents();
        byte[][] pdfDocuments = this.getPDFByteByAppNo(patents);
        byte[] pdfData = new byte[0];
        // 判断 byte[][] 数组是否为空
        if (!this.isByteEmpty(pdfDocuments)) {
            pdfData = this.mergeFirstPage(pdfDocuments);
        }
        return pdfData;
    }

    /**
     * 判断文件数组是否为空
     * @param pdfDocuments
     * @return
     */
    private boolean isByteEmpty(byte[][] pdfDocuments) {
        return pdfDocuments == null || pdfDocuments.length == 0 || Arrays.stream(pdfDocuments).allMatch(array -> array == null || array.length == 0);
    }

    /**
     * 3
     * @param pdfDatas
     * @return
     * @throws IOException
     */
    public byte[] mergeFirstPage(byte[][] pdfDatas) throws IOException{
        //创建一个输出流
        try {
            // 创建一个PDFMergerUtility实例
            PDFMergerUtility merger = new PDFMergerUtility();
            PDDocument resultDocument = new PDDocument();
            //逐个处理每个pdf文件
            for (byte[] pdfData : pdfDatas) {
                // 加载每个输入的PDF文档
                PDDocument document = PDDocument.load(pdfData);
                // 获取第一页
                PDPage firstPage = document.getPage(0);
                // 创建一个新的文档用于保存第一页
                PDDocument firstPageDocument = new PDDocument();
                firstPageDocument.addPage(firstPage);
                // 将第一页添加到合并器中
                merger.appendDocument(resultDocument, firstPageDocument);
                // 关闭当前处理的文档
                document.close();
                firstPageDocument.close();
            }
            ByteArrayOutputStream out = new ByteArrayOutputStream();
            resultDocument.save(out);
            resultDocument.close();
            return out.toByteArray();
        } catch (FileNotFoundException e) {
            throw new FileNotFoundException();
        }
    }

    /**
     * 2
     * 根据查询到的专利信息获取它公告或公开专利的pdf文档数据流
     * @param patents
     * @return
     */
    public byte[][] getPDFByteByAppNo(List<PatentColumnDTO> patents){
        List<byte[]> pdfDatas = new ArrayList<>();
        //遍历传入专利集合
        for (PatentColumnDTO item : patents) {
            //判断申请号是否为空
            if (item.getAppNo() != null) {
                String appNo = item.getAppNo();
                Integer type = 1;
                //获取公告专利pdf文档guid
                String pdfGuid = FormatUtil.getPDFFormat(appNo, type);

                byte[] pdfData = new byte[0];
                try {
                    pdfData = fileManagerService.downloadSystemFileFromFMS(pdfGuid);
                    if (pdfData == null  || pdfData.length == 0) {
                        //获取公开专利pdf文档guid
                        Integer type2 = 0;
                        String pdfGuid2 = FormatUtil.getPDFFormat(appNo, type2);
                        pdfData = fileManagerService.downloadSystemFileFromFMS(pdfGuid2);
                        if (pdfData == null  || pdfData.length == 0) {
                            continue;
                        } else {
                            pdfDatas.add(pdfData);
                        }
                    } else {
                        pdfDatas.add(pdfData);
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                    continue;//继续处理下一件专利
                }
            }
        }
        byte[][] pdfDataArray = new byte[pdfDatas.size()][];
        return pdfDatas.toArray(pdfDataArray);
    }
}