package jnpf.dmsService;

import jnpf.audit.sdk.annotation.AuditLog;
import jnpf.base.UserInfo;
import jnpf.dmsEntity.compare.DmsCompareRequest;
import jnpf.dmsEntity.compare.DmsCompareTicket;
import jnpf.dmsEntity.permission.entity.DmsFileVersionEntity;
import jnpf.dmsEntity.permission.enums.DmsPermissionAction;
import jnpf.dmsEntity.permission.enums.DmsResourceType;
import jnpf.dmsEntity.preview.form.DmsFilePreviewTicketRequest;
import jnpf.dmsEntity.preview.vo.DmsFilePreviewTicketVO;
import jnpf.dmsMapper.DmsFileVersionMapper;
import jnpf.dmsPermission.DmsCurrentIdentity;
import jnpf.exception.DataException;
import lombok.RequiredArgsConstructor;
import org.springframework.stereotype.Service;
import java.nio.charset.StandardCharsets;
import java.util.Locale;
import java.util.UUID;

@Service
@RequiredArgsConstructor
public class DmsFileCompareService {
    private final DmsCurrentIdentity identity;
    private final DmsPermissionDecisionService permissions;
    private final DmsFileVersionMapper versions;
    private final DmsFilePreviewService previews;
    private final DmsCompareTicketIssuer issuer;

    @AuditLog(action = "FILE_VERSION_COMPARE", label = "文件版本比较", bizModule = "DMS",
            bizCodeExpr = "#p0.documentId",
            extraExpr = "{'historicalVersionId': #p0.historicalVersionId, 'currentVersionId': #p0.currentVersionId}")
    public String createTicket(DmsCompareRequest request) {
        UserInfo user = identity.requireUser();
        String tenant = identity.tenantId(user);
        permissions.requireAllowed(DmsResourceType.FILE_VERSION, request.getCurrentVersionId(), DmsPermissionAction.READ);
        permissions.requireAllowed(DmsResourceType.FILE_VERSION, request.getHistoricalVersionId(), DmsPermissionAction.READ);
        DmsFileVersionEntity current = versions.selectCurrentEffective(tenant, request.getDocumentId());
        DmsFileVersionEntity historical = versions.selectReadableByTenantAndId(tenant, request.getHistoricalVersionId());
        validatePair(request, current, historical);
        DmsCompareTicket ticket = new DmsCompareTicket();
        ticket.setTenantId(tenant);
        ticket.setUserId(user.getUserId());
        ticket.setDocumentId(request.getDocumentId());
        ticket.setHistoricalLabel(label(historical));
        ticket.setCurrentLabel(label(current));
        ticket.setHistorical(preview(historical.getId(), request.getOperationId(), "historical"));
        ticket.setCurrent(preview(current.getId(), request.getOperationId(), "current"));
        ticket.setExpiresAt(Math.min(ticket.getHistorical().getExpiresAt().getTime(), ticket.getCurrent().getExpiresAt().getTime()));
        return issuer.issue(ticket, Math.max(1, (ticket.getExpiresAt() - System.currentTimeMillis()) / 1000));
    }

    static void validatePair(DmsCompareRequest request, DmsFileVersionEntity current, DmsFileVersionEntity historical) {
        if (current == null || !current.getId().equals(request.getCurrentVersionId())) {
            throw new DataException("现行版本已变化，请刷新文件列表后重新比较");
        }
        if (historical == null || !request.getDocumentId().equals(current.getDocumentId())
                || !request.getDocumentId().equals(historical.getDocumentId())
                || historical.getId().equals(current.getId())
                || historical.getVersionNo() == null || current.getVersionNo() == null
                || historical.getVersionNo() >= current.getVersionNo()) {
            throw new DataException("请选择同一文件之前修订的历史版本");
        }
        if (!isDocx(current.getFileName()) || !isDocx(historical.getFileName())) {
            throw new DataException("版本比较目前仅支持 DOCX 文件");
        }
    }

    private DmsFilePreviewTicketVO preview(UUID id, UUID operationId, String side) {
        DmsFilePreviewTicketRequest request = new DmsFilePreviewTicketRequest();
        request.setResourceType(DmsResourceType.FILE_VERSION);
        request.setResourceId(id);
        request.setOperationId(UUID.nameUUIDFromBytes((operationId + ":compare:" + side + ":" + id).getBytes(StandardCharsets.UTF_8)));
        return previews.createTicket(request);
    }

    private static boolean isDocx(String name) {
        return name != null && name.toLowerCase(Locale.ROOT).endsWith(".docx");
    }

    private static String label(DmsFileVersionEntity version) {
        return version.getVersionLabel() == null || version.getVersionLabel().trim().isEmpty()
                ? "v" + version.getVersionNo() : version.getVersionLabel();
    }
}