package jnpf.fileStorage.dms;

import jakarta.servlet.http.HttpServletResponse;
import jnpf.dms.DmsTicketLifecycleApi;
import jnpf.dms.DmsTicketLifecycleChecks;
import jnpf.dmsEntity.download.model.DmsFileDownloadTicket;
import jnpf.dmsEntity.preview.enums.DmsWatermarkTargetType;
import jnpf.exception.DataException;
import jnpf.base.ActionResult;
import jnpf.onlyoffice.DmsDownloadPdfApi;
import jnpf.onlyoffice.DmsDownloadPdfRequest;
import jnpf.util.TicketUtil;
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.beans.factory.annotation.Autowired;
import org.springframework.http.ContentDisposition;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.stereotype.Service;

import java.io.ByteArrayOutputStream;
import java.nio.charset.StandardCharsets;
import java.util.Locale;
import java.util.Objects;
import java.util.UUID;

@Service
public class DmsFileDownloadStorageService {
    private static final String DMS_STORAGE_PLATFORM = "seaweedfs-1";
    private static final long MAX_WATERMARK_SOURCE_BYTES = 100L * 1024L * 1024L;

    private final FileStorageService fileStorageService;
    private final TicketReader ticketReader;
    private final DmsFileWatermarkService watermarkService;
    private final DmsDownloadPdfApi pdfRenderer;
    private final DmsPersistentPdfRecoveryReporter recoveryReporter;

    @Autowired
    public DmsFileDownloadStorageService(FileStorageService fileStorageService,
                                         DmsFileWatermarkService watermarkService,
                                         DmsDownloadPdfApi pdfRenderer,
                                         DmsPersistentPdfRecoveryReporter recoveryReporter, DmsTicketLifecycleApi lifecycleApi) {
        this(fileStorageService, ticket -> DmsTicketLifecycleChecks.download(TicketUtil.parseTicket(ticket), lifecycleApi, "jnpf-file"), watermarkService, pdfRenderer,
                recoveryReporter);
    }

    DmsFileDownloadStorageService(FileStorageService fileStorageService, TicketReader ticketReader,
                                  DmsFileWatermarkService watermarkService, DmsDownloadPdfApi pdfRenderer) {
        this(fileStorageService, ticketReader, watermarkService, pdfRenderer, null);
    }

    DmsFileDownloadStorageService(FileStorageService fileStorageService, TicketReader ticketReader,
                                  DmsFileWatermarkService watermarkService, DmsDownloadPdfApi pdfRenderer,
                                  DmsPersistentPdfRecoveryReporter recoveryReporter) {
        this.fileStorageService = fileStorageService;
        this.ticketReader = ticketReader;
        this.watermarkService = watermarkService;
        this.pdfRenderer = pdfRenderer;
        this.recoveryReporter = recoveryReporter;
    }

    public void stream(UUID fileVersionId, String accessTicket, HttpServletResponse response) {
        stream(fileVersionId, accessTicket, null, response);
    }

    public void stream(UUID fileVersionId, String accessTicket, String format, HttpServletResponse response) {
        DmsFileDownloadTicket payload = parse(accessTicket);
        if (!fileVersionId.equals(payload.getFileVersionId())) {
            throw new DataException("DMS 下载票据与文件版本不匹配");
        }
        if (!DMS_STORAGE_PLATFORM.equals(payload.getStoragePlatform())) {
            throw new DataException("DMS 下载票据的存储平台无效");
        }
        boolean pdf = !isBlank(format);
        if (pdf && !"pdf".equalsIgnoreCase(format.trim())) {
            throw new DataException("不支持的下载格式，format 仅支持 pdf");
        }
        String lowerName = payload.getFileName().toLowerCase(Locale.ROOT);
        if (pdf && !lowerName.endsWith(".doc") && !lowerName.endsWith(".docx")
                && !lowerName.endsWith(".pdf")) {
            throw new DataException("仅支持将 Word 文件转换为 PDF 下载");
        }

        MinioFileStorage storage = fileStorageService.getFileStorageVerify(payload.getStoragePlatform());
        if (!Objects.equals(storage.getBucketName(), payload.getBucketName())) {
            throw new DataException("DMS 下载票据的存储桶与当前配置不匹配");
        }

        if (pdf && (lowerName.endsWith(".doc") || lowerName.endsWith(".docx"))
                && reusablePersistentPdf(payload)) {
            if (streamPersistentPdf(payload, response)) return;
        }
        if (pdf && (lowerName.endsWith(".doc") || lowerName.endsWith(".docx"))) {
            streamPdf(payload, accessTicket, response);
            return;
        }

        FileInfo fileInfo = new FileInfo()
                .setPlatform(payload.getStoragePlatform())
                .setBasePath(empty(payload.getBasePath()))
                .setPath(payload.getObjectPath())
                .setFilename(payload.getObjectName())
                .setOriginalFilename(payload.getFileName())
                .setContentType(payload.getMimeType())
                .setSize(payload.getSizeBytes());
        response.setContentType(pdf ? MediaType.APPLICATION_PDF_VALUE : isBlank(payload.getMimeType())
                ? MediaType.APPLICATION_OCTET_STREAM_VALUE : payload.getMimeType());
        response.setHeader(HttpHeaders.CONTENT_DISPOSITION, ContentDisposition.attachment()
                .filename(payload.getFileName(), StandardCharsets.UTF_8).build().toString());
        response.setHeader(HttpHeaders.CACHE_CONTROL, "no-store");
        try {
            if (payload.getWatermarks() == null || payload.getWatermarks().isEmpty()) {
                if (payload.getSizeBytes() != null && payload.getSizeBytes() >= 0) {
                    response.setContentLengthLong(payload.getSizeBytes());
                }
                fileStorageService.download(fileInfo).outputStream(response.getOutputStream());
                return;
            }
            DmsWatermarkTargetType targetType = DmsWatermarkTargetType.from(
                    payload.getFileName(), payload.getMimeType());
            if (targetType == DmsWatermarkTargetType.UNSUPPORTED) {
                throw new DataException("该文件格式不支持动态水印");
            }
            if (targetType == DmsWatermarkTargetType.IMAGE) {
                response.setContentType(DmsImageWatermarkService.contentType(
                        payload.getFileName(), payload.getMimeType()));
            }
            long sourceLimit = targetType == DmsWatermarkTargetType.IMAGE
                    ? DmsImageWatermarkService.MAX_SOURCE_BYTES : MAX_WATERMARK_SOURCE_BYTES;
            if (payload.getSizeBytes() != null
                    && payload.getSizeBytes() > sourceLimit) {
                throw new DataException(targetType == DmsWatermarkTargetType.IMAGE
                        ? "图片超过动态水印处理上限（50 MB）"
                        : "DOCX 文件超过动态水印处理上限（100 MB）");
            }
            byte[] result = watermarkService.loadAndApply(() -> {
                DmsBoundedByteArrayOutputStream source = new DmsBoundedByteArrayOutputStream(sourceLimit,
                        targetType == DmsWatermarkTargetType.IMAGE
                                ? "图片超过动态水印处理上限（50 MB）"
                                : "DOCX 文件超过动态水印处理上限（100 MB）");
                fileStorageService.download(fileInfo).outputStream(source);
                return source.toByteArrayAndRelease();
            }, payload);
            response.setContentLengthLong(result.length);
            response.getOutputStream().write(result);
        } catch (DataException exception) {
            if (!response.isCommitted()) response.reset();
            throw exception;
        } catch (Exception exception) {
            if (!response.isCommitted()) response.reset();
            throw new DataException("下载 DMS 文件失败：" + exception.getMessage());
        }
    }

    private void streamPdf(DmsFileDownloadTicket payload, String accessTicket, HttpServletResponse response) {
        try {
            ActionResult<byte[]> result = pdfRenderer.render(
                    new DmsDownloadPdfRequest(payload.getFileVersionId(), accessTicket));
            if (result == null || result.getCode() != 200 || result.getData() == null
                    || result.getData().length == 0) {
                throw new DataException(result == null || isBlank(result.getMsg())
                        ? "DOCX 转换为 PDF 失败" : result.getMsg());
            }
            byte[] bytes = result.getData();
            String fileName = payload.getFileName();
            fileName = fileName.substring(0, fileName.lastIndexOf('.')) + ".pdf";
            // Only commit download headers once conversion has completed successfully.
            response.setContentType(MediaType.APPLICATION_PDF_VALUE);
            response.setHeader(HttpHeaders.CONTENT_DISPOSITION, ContentDisposition.attachment()
                    .filename(fileName, StandardCharsets.UTF_8).build().toString());
            response.setHeader(HttpHeaders.CACHE_CONTROL, "no-store");
            response.setContentLengthLong(bytes.length);
            response.getOutputStream().write(bytes);
        } catch (DataException exception) {
            throw exception;
        } catch (Exception exception) {
            throw new DataException("DOCX 转换为 PDF 下载失败，请稍后重试");
        }
    }

    private boolean reusablePersistentPdf(DmsFileDownloadTicket payload) {
        return (payload.getWatermarks() == null || payload.getWatermarks().isEmpty())
                && payload.getPdfSource() != null
                && payload.getPdfSource().getObjectKey() != null
                && payload.getPdfSource().getObjectKey().startsWith("dms-derived/pdf/")
                && !payload.getPdfSource().getObjectKey().contains("..")
                && payload.getPdfSource().getSizeBytes() != null
                && payload.getPdfSource().getSizeBytes() > 0;
    }

    private boolean streamPersistentPdf(DmsFileDownloadTicket payload, HttpServletResponse response) {
        String key = payload.getPdfSource().getObjectKey();
        int slash = key.lastIndexOf('/');
        if (slash < 0 || slash == key.length() - 1) return false;
        String original = payload.getFileName();
        int dot = original.lastIndexOf('.');
        String fileName = (dot > 0 ? original.substring(0, dot) : original) + ".pdf";
        FileInfo fileInfo = new FileInfo()
                .setPlatform(payload.getStoragePlatform())
                .setBasePath(empty(payload.getBasePath()))
                .setPath(key.substring(0, slash + 1))
                .setFilename(key.substring(slash + 1))
                .setOriginalFilename(fileName)
                .setContentType(MediaType.APPLICATION_PDF_VALUE)
                .setSize(payload.getPdfSource().getSizeBytes());
        try {
            if (!fileStorageService.exists(fileInfo)) {
                reportInvalid(payload, "持久化 PDF 对象不存在");
                return false;
            }
            ByteArrayOutputStream output = new ByteArrayOutputStream();
            fileStorageService.download(fileInfo).outputStream(output);
            byte[] bytes = output.toByteArray();
            if (bytes.length == 0 || bytes.length != payload.getPdfSource().getSizeBytes()) {
                reportInvalid(payload, "持久化 PDF 对象大小不匹配");
                return false;
            }
            response.setContentType(MediaType.APPLICATION_PDF_VALUE);
            response.setHeader(HttpHeaders.CONTENT_DISPOSITION, ContentDisposition.attachment()
                    .filename(fileName, StandardCharsets.UTF_8).build().toString());
            response.setHeader(HttpHeaders.CACHE_CONTROL, "no-store");
            response.setContentLengthLong(bytes.length);
            response.getOutputStream().write(bytes);
            return true;
        } catch (Exception exception) {
            if (!response.isCommitted()) response.reset();
            reportInvalid(payload, "持久化 PDF 对象读取失败");
            return false;
        }
    }

    private void reportInvalid(DmsFileDownloadTicket payload, String reason) {
        if (recoveryReporter != null) recoveryReporter.report(payload, reason);
    }

    DmsFileDownloadTicket parse(String accessTicket) {
        if (isBlank(accessTicket)) {
            throw new DataException("缺少 DMS 下载票据");
        }
        try {
            return DmsFileDownloadTicket.fromRaw(ticketReader.read(accessTicket));
        } catch (RuntimeException exception) {
            throw new DataException("DMS 下载票据无效或已过期");
        }
    }

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

    private boolean isBlank(String value) {
        return value == null || value.trim().isEmpty();
    }

    @FunctionalInterface
    interface TicketReader {
        Object read(String ticket);
    }
}