package jnpf.fileStorage.dms;

import jnpf.base.ActionResult;
import jnpf.base.ActionResultCode;
import jnpf.dmsEntity.preview.model.DmsFilePreviewTicket;
import jnpf.dmsEntity.storage.form.DmsPersistentPdfGenerateForm;
import jnpf.dmsEntity.storage.vo.DmsPersistentPdfGenerateVO;
import jnpf.exception.DataException;
import jnpf.onlyoffice.DmsPreviewPdfApi;
import jnpf.onlyoffice.DmsPreviewPdfRequest;
import jnpf.util.JsonUtil;
import jnpf.util.TicketUtil;
import lombok.RequiredArgsConstructor;
import org.dromara.x.file.storage.core.FileInfo;
import org.dromara.x.file.storage.core.FileStorageService;
import org.dromara.x.file.storage.core.platform.MinioFileStorage;
import org.springframework.http.MediaType;
import org.springframework.stereotype.Service;
import org.springframework.web.multipart.MultipartFile;

import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.nio.file.Files;
import java.util.Collections;
import java.util.Locale;
import java.util.Objects;

@Service
@RequiredArgsConstructor
public class DmsPersistentPdfStorageService {
    private static final long TICKET_TTL_SECONDS = 300L;

    private final FileStorageService fileStorageService;
    private final DmsPreviewPdfApi previewPdfApi;

    public DmsPersistentPdfGenerateVO generate(DmsPersistentPdfGenerateForm form) {
        validateSource(form);
        String ticket = TicketUtil.createTicket(JsonUtil.getObjectToString(sourceTicket(form)),
                TICKET_TTL_SECONDS);
        FileInfo stored = null;
        try {
            ActionResult<byte[]> result = previewPdfApi.render(
                    new DmsPreviewPdfRequest(form.getFileVersionId(), ticket));
            if (result == null || !ActionResultCode.SUCCESS.getCode().equals(result.getCode())
                    || result.getData() == null || result.getData().length == 0) {
                throw new DataException(result == null || result.getMsg() == null
                        ? "持久化 PDF 生成失败" : result.getMsg());
            }
            MultipartFile pdf = new GeneratedPdf(form.getFileVersionId() + ".pdf", result.getData());
            stored = fileStorageService.of(pdf)
                    .setPlatform(form.getStoragePlatform())
                    .setPath("dms-derived/pdf/" + form.getFileVersionId() + "/")
                    .setSaveFilename(form.getSourceChecksumSha256() + ".pdf")
                    .setOriginalFilename(pdf.getOriginalFilename())
                    .setHashCalculatorSha256()
                    .upload();
            if (stored == null || stored.getSize() == null || stored.getSize() <= 0
                    || stored.getHashInfo() == null || stored.getHashInfo().getSha256() == null) {
                deleteQuietly(stored);
                throw new DataException("持久化 PDF 保存失败");
            }
            DmsPersistentPdfGenerateVO value = new DmsPersistentPdfGenerateVO();
            value.setObjectKey(empty(stored.getPath()) + stored.getFilename());
            value.setSizeBytes(stored.getSize());
            value.setChecksumSha256(stored.getHashInfo().getSha256().toLowerCase(Locale.ROOT));
            value.setSourceChecksumSha256(form.getSourceChecksumSha256());
            return value;
        } finally {
            TicketUtil.deleteTicket(ticket);
        }
    }

    private void validateSource(DmsPersistentPdfGenerateForm form) {
        String extension = extension(form.getFileName());
        if (!"doc".equals(extension) && !"docx".equals(extension)) {
            throw new DataException("仅支持为 Word 文件生成持久化 PDF");
        }
        MinioFileStorage storage = fileStorageService.getFileStorageVerify(form.getStoragePlatform());
        if (!Objects.equals(storage.getBucketName(), form.getBucketName())) {
            throw new DataException("DMS 原文件存储桶与当前配置不匹配");
        }
    }

    private DmsFilePreviewTicket sourceTicket(DmsPersistentPdfGenerateForm form) {
        DmsFilePreviewTicket ticket = new DmsFilePreviewTicket();
        ticket.setScope(DmsFilePreviewTicket.SCOPE);
        ticket.setTenantId(form.getTenantId());
        ticket.setUserId("dms-pdf-generator");
        ticket.setFileVersionId(form.getFileVersionId());
        ticket.setFileName(form.getFileName());
        ticket.setMimeType(form.getMimeType());
        ticket.setSizeBytes(form.getSizeBytes());
        ticket.setStoragePlatform(form.getStoragePlatform());
        ticket.setBucketName(form.getBucketName());
        ticket.setBasePath(empty(form.getBasePath()));
        ticket.setObjectPath(form.getObjectPath());
        ticket.setObjectName(form.getObjectName());
        ticket.setWatermarks(Collections.emptyList());
        ticket.setExpiresAt(System.currentTimeMillis() + TICKET_TTL_SECONDS * 1000L);
        return ticket;
    }

    private void deleteQuietly(FileInfo stored) {
        if (stored == null) return;
        try { fileStorageService.delete(stored); }
        catch (RuntimeException ignored) { }
    }

    private String extension(String fileName) {
        int dot = fileName == null ? -1 : fileName.lastIndexOf('.');
        return dot < 0 ? "" : fileName.substring(dot + 1).toLowerCase(Locale.ROOT);
    }

    private String empty(String value) { return value == null ? "" : value; }

    private static final class GeneratedPdf implements MultipartFile {
        private final String fileName;
        private final byte[] content;

        private GeneratedPdf(String fileName, byte[] content) {
            this.fileName = fileName;
            this.content = content;
        }

        @Override public String getName() { return "file"; }
        @Override public String getOriginalFilename() { return fileName; }
        @Override public String getContentType() { return MediaType.APPLICATION_PDF_VALUE; }
        @Override public boolean isEmpty() { return content.length == 0; }
        @Override public long getSize() { return content.length; }
        @Override public byte[] getBytes() { return content.clone(); }
        @Override public InputStream getInputStream() { return new ByteArrayInputStream(content); }
        @Override public void transferTo(File destination) throws IOException {
            Files.write(destination.toPath(), content);
        }
    }
}