大型企业文档管理系统架构设计：多部门权限隔离 + 跨区域数据同步方案

// 基于Entity Framework Core的权限模型示例
public class DocumentPermission
{
    public int Id { get; set; }
    public int UserId { get; set; }
    public int DocumentId { get; set; }
    public PermissionLevel Level { get; set; }
    public DateTime GrantedAt { get; set; }
    public int GrantedBy { get; set; }
    
    // 导航属性
    public virtual User User { get; set; }
    public virtual Document Document { get; set; }
}

public enum PermissionLevel
{
    Read = 1,
    Write = 2,
    Delete = 3,
    Share = 4
}

// 权限检查服务
public class PermissionService
{
    private readonly DocumentContext _context;
    
    public PermissionService(DocumentContext context)
    {
        _context = context;
    }
    
    public async Task HasPermissionAsync(int userId, int documentId, PermissionLevel requiredLevel)
    {
        var permission = await _context.DocumentPermissions
            .FirstOrDefaultAsync(p => p.UserId == userId && p.DocumentId == documentId);
            
        return permission != null && permission.Level >= requiredLevel;
    }
}

// 文档同步服务示例
public class DocumentSyncService
{
    private readonly List _regionNodes;
    private readonly IDocumentVersionManager _versionManager;
    
    public async Task SyncDocumentAsync(int documentId, int sourceRegionId, int targetRegionId)
    {
        // 获取文档最新版本信息
        var latestVersion = await _versionManager.GetLatestVersionAsync(documentId);
        
        // 检查目标节点是否已是最新版本
        var targetNode = _regionNodes.FirstOrDefault(n => n.RegionId == targetRegionId);
        if (targetNode != null && await targetNode.HasVersionAsync(documentId, latestVersion.VersionNumber))
        {
            return; // 已同步，无需操作
        }
        
        // 执行差分同步
        var delta = await _versionManager.GetDeltaAsync(documentId, targetRegionId);
        if (delta.HasChanges)
        {
            await targetNode.ApplyDeltaAsync(documentId, delta);
            await _versionManager.UpdateRegionVersionAsync(documentId, targetRegionId, latestVersion.VersionNumber);
        }
    }
    
    // 冲突解决策略
    public async Task ResolveConflictAsync(int documentId, DocumentVersion versionA, DocumentVersion versionB)
    {
        // 采用最后写入获胜策略，可根据业务需求调整
        return versionA.LastModified > versionB.LastModified ? versionA : versionB;
    }
}