package jnpf.dmsService;

import jnpf.base.UserInfo;
import jnpf.dmsEntity.permission.entity.DmsFolderEntity;
import jnpf.dmsEntity.permission.entity.DmsPermissionResourceEntity;
import jnpf.dmsEntity.permission.enums.DmsFolderReorderDirection;
import jnpf.dmsEntity.permission.enums.DmsResourceType;
import jnpf.dmsEntity.permission.form.FolderCopyForm;
import jnpf.dmsEntity.permission.form.FolderAuditSignForm;
import jnpf.dmsEntity.permission.form.FolderMoveForm;
import jnpf.dmsEntity.permission.form.FolderRenameForm;
import jnpf.dmsEntity.permission.form.FolderReorderForm;
import jnpf.dmsEntity.permission.vo.DmsPermissionResourceVO;
import jnpf.dmsIntegration.audit.DmsAuditAdapter;
import jnpf.dmsIntegration.audit.DmsAuditRequestSignResolver;
import jnpf.dmsIntegration.audit.DmsFolderAuditEvent;
import jnpf.dmsIntegration.audit.DmsFolderAuditSnapshot;
import jnpf.dmsMapper.DmsFolderMapper;
import jnpf.dmsMapper.DmsPermissionResourceMapper;
import jnpf.dmsMapper.DmsPermissionRevisionMapper;
import jnpf.dmsPermission.DmsCurrentIdentity;
import jnpf.dmsPermission.DmsPermissionError;
import jnpf.dmsPermission.DmsPermissionException;
import lombok.RequiredArgsConstructor;
import org.springframework.dao.DuplicateKeyException;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.util.ArrayList;
import java.util.Comparator;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.UUID;

@Service
@RequiredArgsConstructor
public class DmsFolderManagementService {
    private static final String COPY_SOURCE_PREFIX = "web-folder-copy:";
    private static final String WEB_FOLDER_REGISTRAR = "jnpf-dms-web";

    private final DmsCurrentIdentity currentIdentity;
    private final DmsFolderMapper folderMapper;
    private final DmsPermissionResourceMapper resourceMapper;
    private final DmsPermissionRevisionMapper permissionRevisionMapper;
    private final DmsPermissionGrantService permissionGrantService;
    private final DmsAuditAdapter auditAdapter;

    @Transactional
    public DmsPermissionResourceVO rename(UUID id, FolderRenameForm form) {
        Actor actor = actor();
        DmsFolderEntity snapshot = requireFolder(actor.tenantId, id);
        lockSiblingSets(actor.tenantId, snapshot.getParentId());
        DmsFolderEntity folder = requireLockedFolder(actor.tenantId, id);
        requireRevision(folder, form.getRevision());
        String name = form.getName().trim();
        if (name.equals(folder.getName())) {
            return requireView(actor.tenantId, id);
        }
        if (folderMapper.siblingNameExists(actor.tenantId, folder.getParentId(), name, id)) {
            throw conflict("同级目录名称已存在", null);
        }
        String oldPath = folderMapper.selectPath(actor.tenantId, id);
        if (folderMapper.rename(actor.tenantId, id, name, folder.getRevision(), actor.userId) != 1) {
            throw revisionConflict();
        }
        auditAdapter.folderChange(folderEvent(id, "UPDATE", "重命名 DMS 文件夹",
                folderSnapshot(folder, oldPath),
                folderSnapshot(actor.tenantId, id, folder.getParentId(), name, folder.getRevision() + 1,
                        folderMapper.selectPath(actor.tenantId, id)),
                form.getRevision(), form));
        return requireView(actor.tenantId, id);
    }

    @Transactional
    public DmsPermissionResourceVO reorder(UUID id, FolderReorderForm form) {
        Actor actor = actor();
        DmsFolderEntity snapshot = requireFolder(actor.tenantId, id);
        lockSiblingSets(actor.tenantId, snapshot.getParentId());
        DmsFolderEntity folder = requireLockedFolder(actor.tenantId, id);
        requireRevision(folder, form.getRevision());
        DmsFolderEntity adjacent = form.getDirection() == DmsFolderReorderDirection.UP
                ? folderMapper.selectPreviousForUpdate(actor.tenantId, folder.getParentId(),
                folder.getSortCode(), folder.getId())
                : folderMapper.selectNextForUpdate(actor.tenantId, folder.getParentId(),
                folder.getSortCode(), folder.getId());
        if (adjacent == null) {
            throw DmsPermissionException.of(DmsPermissionError.INVALID_REQUEST,
                    form.getDirection() == DmsFolderReorderDirection.UP
                            ? "目录已经位于同级第一项" : "目录已经位于同级最后一项");
        }
        long folderSort = folder.getSortCode();
        long adjacentSort = adjacent.getSortCode();
        if (folderMapper.reorder(actor.tenantId, folder.getId(), adjacentSort,
                folder.getRevision(), actor.userId) != 1
                || folderMapper.reorder(actor.tenantId, adjacent.getId(), folderSort,
                adjacent.getRevision(), actor.userId) != 1) {
            throw revisionConflict();
        }
        auditAdapter.dataChange("UPDATE", "调整 DMS 同级目录排序", "dms_folders",
                id.toString(), null, null);
        return requireView(actor.tenantId, id);
    }

    @Transactional
    public DmsPermissionResourceVO move(UUID id, FolderMoveForm form) {
        Actor actor = actor();
        DmsFolderEntity snapshot = requireFolder(actor.tenantId, id);
        if (snapshot.getParentId() == null) {
            throw DmsPermissionException.of(DmsPermissionError.INVALID_RESOURCE_PARENT,
                    "根目录不能剪切移动");
        }
        requireFolder(actor.tenantId, form.getParentId());
        if (Objects.equals(snapshot.getParentId(), form.getParentId())) {
            requireRevision(snapshot, form.getRevision());
            return requireView(actor.tenantId, id);
        }
        if (folderMapper.targetIsSelfOrDescendant(actor.tenantId, id, form.getParentId())) {
            throw DmsPermissionException.of(DmsPermissionError.INVALID_RESOURCE_PARENT,
                    "目录不能移动到自身或其后代目录");
        }

        lockSiblingSets(actor.tenantId, snapshot.getParentId(), form.getParentId());
        DmsFolderEntity folder = requireLockedFolder(actor.tenantId, id);
        requireLockedFolder(actor.tenantId, form.getParentId());
        requireRevision(folder, form.getRevision());
        if (folderMapper.siblingNameExists(actor.tenantId, form.getParentId(), folder.getName(), null)) {
            throw conflict("目标目录下已存在同名目录", null);
        }
        long sortCode = folderMapper.nextSortCode(actor.tenantId, form.getParentId());
        String oldPath = folderMapper.selectPath(actor.tenantId, id);
        if (folderMapper.move(actor.tenantId, id, form.getParentId(), sortCode,
                folder.getRevision(), actor.userId) != 1) {
            throw revisionConflict();
        }
        permissionRevisionMapper.bump(actor.tenantId);
        auditAdapter.folderChange(folderEvent(id, "UPDATE", "移动 DMS 文件夹",
                folderSnapshot(folder, oldPath),
                folderSnapshot(actor.tenantId, id, form.getParentId(), folder.getName(), folder.getRevision() + 1,
                        folderMapper.selectPath(actor.tenantId, id)),
                form.getRevision(), form));
        return requireView(actor.tenantId, id);
    }

    @Transactional
    public DmsPermissionResourceVO copy(UUID id, FolderCopyForm form) {
        Actor actor = actor();
        DmsFolderEntity source = requireFolder(actor.tenantId, id);
        requireFolder(actor.tenantId, form.getParentId());
        if (folderMapper.targetIsSelfOrDescendant(actor.tenantId, id, form.getParentId())) {
            throw DmsPermissionException.of(DmsPermissionError.INVALID_RESOURCE_PARENT,
                    "目录不能复制到自身或其后代目录");
        }
        String requestId = form.getRequestId().trim();
        String rootSourceId = copySourceId(requestId, id);
        resourceMapper.lockSource(actor.tenantId, "SYSTEM", rootSourceId);
        DmsPermissionResourceEntity existing = resourceMapper.selectBySource(
                actor.tenantId, "SYSTEM", rootSourceId);
        if (existing != null) {
            DmsFolderEntity existingFolder = folderMapper.selectByTenantAndId(actor.tenantId, existing.getId());
            if (existingFolder == null || !Objects.equals(existingFolder.getParentId(), form.getParentId())
                    || !actor.userId.equals(existingFolder.getCreatedBy())) {
                throw DmsPermissionException.of(DmsPermissionError.IDEMPOTENCY_CONFLICT,
                        "复制请求 ID 已用于其他目标或用户");
            }
            return requireView(actor.tenantId, existing.getId());
        }

        List<DmsFolderEntity> subtree = folderMapper.selectSubtree(actor.tenantId, id);
        if (subtree.isEmpty()) {
            throw notFound(id);
        }
        lockSiblingSets(actor.tenantId, form.getParentId());
        String rootName = uniqueCopyName(actor.tenantId, form.getParentId(), source.getName());
        long rootSortCode = folderMapper.nextSortCode(actor.tenantId, form.getParentId());
        Map<UUID, UUID> copiedIds = new HashMap<>();
        UUID copiedRootId = null;
        try {
            for (DmsFolderEntity original : subtree) {
                UUID copiedId = resourceMapper.nextUuidV7();
                UUID copiedParentId = original.getId().equals(id)
                        ? form.getParentId() : copiedIds.get(original.getParentId());
                if (copiedParentId == null) {
                    throw DmsPermissionException.of(DmsPermissionError.INVALID_RESOURCE_PARENT,
                            "复制目录结构不完整");
                }
                DmsFolderEntity copy = new DmsFolderEntity();
                copy.setId(copiedId);
                copy.setTenantId(actor.tenantId);
                copy.setParentId(copiedParentId);
                copy.setName(original.getId().equals(id) ? rootName : original.getName());
                copy.setCreatedBy(actor.userId);
                copy.setSortCode(original.getId().equals(id) ? rootSortCode : original.getSortCode());
                copy.setRevision(0L);
                copy.setDeleteMark(null);
                folderMapper.insert(copy);
                insertRegistry(actor.tenantId, copiedId, copySourceId(requestId, original.getId()));
                permissionGrantService.ensureFolderCreatorCreatePermission(
                        actor.tenantId, copiedId, actor.userId);
                copiedIds.put(original.getId(), copiedId);
                if (original.getId().equals(id)) {
                    copiedRootId = copiedId;
                }
            }
        } catch (DuplicateKeyException ex) {
            throw conflict("复制目录时发生名称或资源冲突", ex);
        }
        auditAdapter.dataChange("CREATE", "复制 DMS 目录结构", "dms_folders",
                Objects.requireNonNull(copiedRootId).toString(), null,
                "{\"folderCount\":" + subtree.size() + "}");
        return requireView(actor.tenantId, copiedRootId);
    }

    @Transactional
    public void delete(UUID id, long revision) {
        Actor actor = actor();
        DmsFolderEntity snapshot = requireFolder(actor.tenantId, id);
        if (snapshot.getParentId() == null) {
            throw DmsPermissionException.of(DmsPermissionError.INVALID_RESOURCE_PARENT,
                    "根目录不能删除");
        }
        lockSiblingSets(actor.tenantId, snapshot.getParentId());
        DmsFolderEntity folder = requireLockedFolder(actor.tenantId, id);
        requireRevision(folder, revision);
        if (folderMapper.hasContents(actor.tenantId, id)) {
            throw DmsPermissionException.of(DmsPermissionError.INVALID_REQUEST,
                    "只能删除不包含子目录和文件的空目录");
        }
        String oldPath = folderMapper.selectPath(actor.tenantId, id);
        if (folderMapper.softDelete(actor.tenantId, id, folder.getRevision(), actor.userId) != 1) {
            throw revisionConflict();
        }
        permissionRevisionMapper.bump(actor.tenantId);
        auditAdapter.folderChange(folderEvent(id, "DELETE", "删除 DMS 文件夹",
                folderSnapshot(folder, oldPath), null, revision, null));
    }

    private String uniqueCopyName(String tenantId, UUID parentId, String sourceName) {
        String base = sourceName.length() <= 294 ? sourceName : sourceName.substring(0, 294);
        String candidate = base + " - 副本";
        int suffix = 2;
        while (folderMapper.siblingNameExists(tenantId, parentId, candidate, null)) {
            String ending = " - 副本 (" + suffix++ + ")";
            int baseLength = Math.min(sourceName.length(), 300 - ending.length());
            candidate = sourceName.substring(0, baseLength) + ending;
            if (suffix > 1000) {
                throw conflict("无法为复制目录生成唯一名称", null);
            }
        }
        return candidate;
    }

    private void insertRegistry(String tenantId, UUID id, String sourceId) {
        DmsPermissionResourceEntity registry = new DmsPermissionResourceEntity();
        registry.setId(id);
        registry.setTenantId(tenantId);
        registry.setResourceType(DmsResourceType.FOLDER.name());
        registry.setSourceType("SYSTEM");
        registry.setSourceId(sourceId);
        registry.setRegisteredBy(WEB_FOLDER_REGISTRAR);
        resourceMapper.insert(registry);
    }

    private String copySourceId(String requestId, UUID sourceId) {
        return COPY_SOURCE_PREFIX + requestId + ":" + sourceId;
    }

    private Actor actor() {
        currentIdentity.requirePermissionAdministrator();
        UserInfo user = currentIdentity.requireUser();
        return new Actor(currentIdentity.tenantId(user), user.getUserId().trim());
    }

    private DmsFolderEntity requireFolder(String tenantId, UUID id) {
        DmsFolderEntity folder = folderMapper.selectByTenantAndId(tenantId, id);
        if (folder == null) {
            throw notFound(id);
        }
        return folder;
    }

    private DmsFolderEntity requireLockedFolder(String tenantId, UUID id) {
        DmsFolderEntity folder = folderMapper.selectByTenantAndIdForUpdate(tenantId, id);
        if (folder == null) {
            throw notFound(id);
        }
        return folder;
    }

    private void requireRevision(DmsFolderEntity folder, Long expectedRevision) {
        if (expectedRevision == null || !expectedRevision.equals(folder.getRevision())) {
            throw revisionConflict();
        }
    }

    private DmsPermissionResourceVO requireView(String tenantId, UUID id) {
        DmsPermissionResourceVO view = resourceMapper.selectView(tenantId, id);
        if (view == null) {
            throw notFound(id);
        }
        return view;
    }

    private void lockSiblingSets(String tenantId, UUID... parentIds) {
        List<UUID> ids = new ArrayList<>();
        for (UUID parentId : parentIds) {
            if (!ids.contains(parentId)) {
                ids.add(parentId);
            }
        }
        ids.sort(Comparator.comparing(id -> id == null ? "" : id.toString()));
        for (UUID parentId : ids) {
            folderMapper.lockSiblingSet(tenantId, parentId);
        }
    }

    private DmsPermissionException revisionConflict() {
        return DmsPermissionException.of(DmsPermissionError.REVISION_CONFLICT,
                "目录已被其他管理员修改，请刷新后重试");
    }

    private DmsPermissionException notFound(UUID id) {
        return DmsPermissionException.of(DmsPermissionError.RESOURCE_NOT_FOUND,
                "目录不存在或已删除: " + id);
    }

    private DmsPermissionException conflict(String message, Throwable cause) {
        DmsPermissionException exception = DmsPermissionException.of(DmsPermissionError.SOURCE_CONFLICT, message);
        if (cause != null) {
            exception.initCause(cause);
        }
        return exception;
    }

    private DmsFolderAuditEvent folderEvent(UUID id, String actionCode, String actionLabel,
                                            DmsFolderAuditSnapshot before,
                                            DmsFolderAuditSnapshot after,
                                            Long requestRevision,
                                            FolderAuditSignForm signForm) {
        return DmsFolderAuditEvent.builder()
                .folderId(id)
                .actionCode(actionCode)
                .actionLabel(actionLabel)
                .before(before)
                .after(after)
                .requestRevision(requestRevision)
                .relatedSigns(DmsAuditRequestSignResolver.resolve(
                        signForm == null ? null : signForm.getAuditSignParameters()))
                .entryType("MENU")
                .entryId("dms-folder-management")
                .entryName("DMS 文件夹管理")
                .build();
    }

    private DmsFolderAuditSnapshot folderSnapshot(DmsFolderEntity folder, String path) {
        return folderSnapshot(folder.getTenantId(), folder.getId(), folder.getParentId(), folder.getName(),
                folder.getRevision(), path);
    }

    private DmsFolderAuditSnapshot folderSnapshot(String tenantId, UUID id, UUID parentId, String name,
                                                   Long revision, String path) {
        return DmsFolderAuditSnapshot.builder()
                .id(id)
                .parentId(parentId)
                .name(name)
                .parentName(parentName(tenantId, parentId))
                .revision(revision)
                .path(path)
                .build();
    }

    private String parentName(String tenantId, UUID parentId) {
        if (parentId == null) {
            return "根目录";
        }
        DmsFolderEntity parent = folderMapper.selectByTenantAndId(tenantId, parentId);
        return parent == null ? null : parent.getName();
    }

    private static class Actor {
        private final String tenantId;
        private final String userId;

        private Actor(String tenantId, String userId) {
            this.tenantId = tenantId;
            this.userId = userId;
        }
    }
}