using System;
using System.Collections.Generic;
using TellmePdmsPluging.Models;
using Aveva.ApplicationFramework;
using Aveva.Pdms.Database;
using Aveva.ApplicationFramework.Presentation;
using System.Linq;

namespace TellmePdmsPluging.Core
{
    public class PdmsManager
    {
        private static PdmsManager _instance;
        private static readonly object _lock = new object();
        private static readonly object _attributeCacheLock = new object();
        private static readonly Dictionary<string, DbAttribute> _attributeCache = new Dictionary<string, DbAttribute>(StringComparer.OrdinalIgnoreCase);
        private static string _lastExportErrorMessage;
        private static readonly string[] LinkedAttributeCandidates = new[]
        {
            "ATCONN", "BRCON", "DEPREF", "ECRFA", "CONNE", "CONNS", "ATTC",
            "CTYA", "CTYE", "CTYO", "CTYS", "ENDPOI", "CLNK", "CONN", "DCON", "DPCO"
        };

        public static PdmsManager Instance
        {
            get
            {
                if (_instance == null)
                {
                    lock (_lock)
                    {
                        if (_instance == null)
                            _instance = new PdmsManager();
                    }
                }
                return _instance;
            }
        }

        private PdmsManager()
        {
        }

        public SimplifyModelResult SimplifyModel(SimplifyModelRequest request)
        {
            var effectiveRequest = request ?? new SimplifyModelRequest();
            effectiveRequest.ApplyDefaults();

            var result = new SimplifyModelResult
            {
                DryRun = effectiveRequest.DryRun,
                SkipLinkedElements = effectiveRequest.SkipLinkedElements,
                StartedAt = DateTime.Now
            };

            try
            {
                if (!IsPdmsConnected())
                {
                    result.Success = false;
                    result.CompletedAt = DateTime.Now;
                    result.Message = "PDMS 未连接";
                    result.Errors.Add("PDMS 未连接");
                    return result;
                }

                var currentMdb = MDB.CurrentMDB;
                var designDb = currentMdb?.GetFirstDB(DbType.Design);
                if (designDb == null || designDb.World == null)
                {
                    result.Success = false;
                    result.CompletedAt = DateTime.Now;
                    result.Message = "未找到有效的设计数据库";
                    result.Errors.Add("未找到有效的设计数据库");
                    return result;
                }

                if (!effectiveRequest.DryRun && IsDbReadOnly(designDb))
                {
                    result.Success = false;
                    result.CompletedAt = DateTime.Now;
                    result.Message = "当前Design DB为只读，无法执行真实删除";
                    result.Errors.Add("当前Design DB为只读，无法执行真实删除");
                    return result;
                }

                var context = new SimplifyContext(effectiveRequest, result);
                var sites = designDb.World.Members();
                bool processed = false;

                if (sites != null)
                {
                    foreach (var site in sites)
                    {
                        if (!IsElementValid(site) || !string.Equals(GetElementTypeName(site), "SITE", StringComparison.OrdinalIgnoreCase))
                        {
                            continue;
                        }

                        var zones = site.Members();
                        if (zones == null)
                        {
                            continue;
                        }

                        foreach (var zone in zones)
                        {
                            if (!IsElementValid(zone) || !string.Equals(GetElementTypeName(zone), "ZONE", StringComparison.OrdinalIgnoreCase))
                            {
                                continue;
                            }

                            if (!context.ShouldProcessZone(zone))
                            {
                                continue;
                            }

                            processed = true;
                            context.EnterZone(zone);
                            context.ProcessChildren(zone);
                        }
                    }
                }

                if (!effectiveRequest.DryRun && processed && result.RemovedCount > 0)
                {
                    string persistError;
                    if (!TryPersistCurrentMdbChanges("TellmePdms simplify model", out persistError))
                    {
                        result.Errors.Add("删除已执行，但保存更改失败: " + persistError);
                    }
                }

                result.Success = processed && result.Errors.Count == 0;
                if (!processed)
                {
                    result.Message = "未找到符合过滤条件的Zone";
                }
                else if (result.Success)
                {
                    result.Message = result.DryRun ? "模型轻量化干跑完成" : "模型轻量化完成";
                }
                else
                {
                    var topErrors = result.Errors.Take(3).ToArray();
                    var errorSummary = topErrors.Length == 0 ? "UNKNOWN_ERROR" : string.Join(" | ", topErrors);
                    result.Message = (result.DryRun ? "模型轻量化干跑完成，但存在错误: " : "模型轻量化完成，但存在错误: ") + errorSummary;
                }

                if (effectiveRequest.SkipLinkedElements && result.SkippedLinkedCount > 0)
                {
                    result.Message += "；已跳过连接元素 " + result.SkippedLinkedCount + " 个";
                }

                result.CompletedAt = DateTime.Now;
                return result;
            }
            catch (Exception ex)
            {
                result.Success = false;
                result.Errors.Add(ex.Message);
                result.Message = "模型轻量化失败";
                result.CompletedAt = DateTime.Now;
                return result;
            }
        }

        public ShrinkwrapModelResult ShrinkwrapModel(ShrinkwrapModelRequest request)
        {
            var effectiveRequest = request ?? new ShrinkwrapModelRequest();
            effectiveRequest.ApplyDefaults();

            var result = new ShrinkwrapModelResult
            {
                DryRun = effectiveRequest.DryRun,
                SkipLinkedElements = effectiveRequest.SkipLinkedElements,
                Padding = effectiveRequest.Padding,
                DeletionMode = "conservative",
                StartedAt = DateTime.Now
            };

            try
            {
                if (!IsPdmsConnected())
                {
                    result.Success = false;
                    result.CompletedAt = DateTime.Now;
                    result.Message = "PDMS 未连接";
                    result.Errors.Add("PDMS 未连接");
                    return result;
                }

                var currentMdb = MDB.CurrentMDB;
                var designDb = currentMdb?.GetFirstDB(DbType.Design);
                if (designDb == null || designDb.World == null)
                {
                    result.Success = false;
                    result.CompletedAt = DateTime.Now;
                    result.Message = "未找到有效的设计数据库";
                    result.Errors.Add("未找到有效的设计数据库");
                    return result;
                }

                if (!effectiveRequest.DryRun && IsDbReadOnly(designDb))
                {
                    result.Success = false;
                    result.CompletedAt = DateTime.Now;
                    result.Message = "当前Design DB为只读，无法执行真实删除";
                    result.Errors.Add("当前Design DB为只读，无法执行真实删除");
                    return result;
                }

                var context = new ShrinkwrapContext(effectiveRequest, result);
                var sites = designDb.World.Members();
                bool processed = false;

                if (sites != null)
                {
                    foreach (var site in sites)
                    {
                        if (!IsElementValid(site) || !string.Equals(GetElementTypeName(site), "SITE", StringComparison.OrdinalIgnoreCase))
                        {
                            continue;
                        }

                        var zones = site.Members();
                        if (zones == null)
                        {
                            continue;
                        }

                        foreach (var zone in zones)
                        {
                            if (!IsElementValid(zone) || !string.Equals(GetElementTypeName(zone), "ZONE", StringComparison.OrdinalIgnoreCase))
                            {
                                continue;
                            }

                            if (!context.ShouldProcessZone(zone))
                            {
                                continue;
                            }

                            processed = true;
                            context.EnterZone(zone);
                            context.ProcessZone(zone);
                        }
                    }
                }

                if (!effectiveRequest.DryRun && processed && result.RemovedCount > 0)
                {
                    string persistError;
                    if (!TryPersistCurrentMdbChanges("TellmePdms shrinkwrap model", context.GetTouchedWritableDbs(), result.ProcessedDbNames, out persistError))
                    {
                        result.FatalErrors.Add("删除已执行，但保存更改失败: " + persistError);
                    }
                }

                result.Success = processed && result.Errors.Count == 0 && result.FatalErrors.Count == 0;
                if (!processed)
                {
                    result.Message = "未找到符合过滤条件的Zone";
                }
                else if (result.Success)
                {
                    result.Message = result.DryRun ? "外壳保留干跑完成" : "外壳保留完成";
                }
                else
                {
                    var mergedErrors = result.FatalErrors.Concat(result.Errors).Take(3).ToArray();
                    var topErrors = mergedErrors;
                    var errorSummary = topErrors.Length == 0 ? "UNKNOWN_ERROR" : string.Join(" | ", topErrors);
                    result.Message = (result.DryRun ? "外壳保留干跑完成，但存在错误: " : "外壳保留完成，但存在错误: ") + errorSummary;
                }

                if (effectiveRequest.SkipLinkedElements && result.SkippedLinkedCount > 0)
                {
                    result.Message += "；已跳过连接元素 " + result.SkippedLinkedCount + " 个";
                }

                if (result.SkippedUnsafeCount > 0)
                {
                    result.Message += "；已跳过不安全元素 " + result.SkippedUnsafeCount + " 个";
                }

                result.CompletedAt = DateTime.Now;
                return result;
            }
            catch (Exception ex)
            {
                result.Success = false;
                result.FatalErrors.Add(ex.Message);
                result.Message = "外壳保留失败";
                result.CompletedAt = DateTime.Now;
                return result;
            }
        }

        public ModelStatusResponse GetModelStatus()
        {
            try
            {
                // 检查PDMS是否连接
                if (!IsPdmsConnected())
                {
                    return new ModelStatusResponse
                    {
                        ModelLoaded = false
                    };
                }

                return new ModelStatusResponse
                {
                    ModelLoaded = true,
                    ProjectInfo = GetProjectInfo(),
                    ModelStatistics = GetModelStatistics(),
                    SessionInfo = GetSessionInfo(),
                    ExportDiagnostics = GetExportDiagnostics(null)
                };
            }
            catch (Exception ex)
            {
                // 记录错误日志
                System.Diagnostics.Debug.WriteLine($"获取PDMS模型状态失败: {ex.Message}");
                return new ModelStatusResponse
                {
                    ModelLoaded = false,
                    ExportDiagnostics = GetExportDiagnostics(null)
                };
            }
        }

        public OpenProjectResult OpenProject(OpenProjectRequest request)
        {
            var effectiveRequest = request ?? new OpenProjectRequest();
            effectiveRequest.ApplyDefaults();

            var result = new OpenProjectResult
            {
                ProjectName = effectiveRequest.ProjectName,
                FileSize = -1,
                PolygonCount = -1,
                FeatureCount = -1,
                CompletedAt = DateTime.Now
            };

            try
            {
                var currentProject = Project.CurrentProject;
                if (currentProject == null)
                {
                    result.Success = false;
                    result.Message = "Project.CurrentProject 为空，无法打开项目";
                    return result;
                }

                bool alreadyOpen = false;
                try
                {
                    alreadyOpen = currentProject.IsOpen();
                }
                catch
                {
                    alreadyOpen = false;
                }

                result.WasAlreadyOpen = alreadyOpen;

                // 如果已经打开且未指定目标项目名，则直接返回成功
                if (alreadyOpen && string.IsNullOrEmpty(effectiveRequest.ProjectName))
                {
                    result.Success = true;
                    result.Message = "项目已打开";
                    PopulateOpenProjectMetrics(result);
                    return result;
                }

                if (string.IsNullOrEmpty(effectiveRequest.ProjectName))
                {
                    result.Success = false;
                    result.Message = "ProjectName 不能为空";
                    return result;
                }

                bool opened = currentProject.Open(
                    effectiveRequest.ProjectName,
                    effectiveRequest.UserName ?? string.Empty,
                    effectiveRequest.Password ?? string.Empty);

                result.Success = opened;
                result.Message = opened ? "项目打开成功" : "项目打开失败（Open 返回 false）";
                if (opened)
                {
                    PopulateOpenProjectMetrics(result);
                }
                result.CompletedAt = DateTime.Now;
                return result;
            }
            catch (Exception ex)
            {
                result.Success = false;
                result.Message = "项目打开异常: " + ex.Message;
                result.CompletedAt = DateTime.Now;
                return result;
            }
        }

        public CloseProjectResult CloseProject(CloseProjectRequest request)
        {
            var effectiveRequest = request ?? new CloseProjectRequest();
            effectiveRequest.ApplyDefaults();

            var result = new CloseProjectResult
            {
                CompletedAt = DateTime.Now
            };

            try
            {
                var currentProject = Project.CurrentProject;
                if (currentProject == null)
                {
                    result.Success = false;
                    result.Message = "Project.CurrentProject 为空，无法关闭项目";
                    return result;
                }

                bool isOpen = false;
                try
                {
                    isOpen = currentProject.IsOpen();
                }
                catch
                {
                    isOpen = false;
                }

                result.WasOpen = isOpen;
                result.ProjectName = GetProjectNameSafe(currentProject);

                if (!isOpen)
                {
                    result.Success = true;
                    result.Message = "当前没有已打开项目";
                    result.CompletedAt = DateTime.Now;
                    return result;
                }

                var projectType = currentProject.GetType();

                var closeWithForce = projectType.GetMethod("Close", new[] { typeof(bool) });
                if (closeWithForce != null)
                {
                    closeWithForce.Invoke(currentProject, new object[] { effectiveRequest.Force });
                }
                else
                {
                    var closeNoArg = projectType.GetMethod("Close", Type.EmptyTypes);
                    if (closeNoArg == null)
                    {
                        result.Success = false;
                        result.Message = "未找到可用的 Project.Close 方法";
                        result.CompletedAt = DateTime.Now;
                        return result;
                    }

                    closeNoArg.Invoke(currentProject, null);
                }

                result.Success = true;
                result.Message = "项目关闭成功";
                result.CompletedAt = DateTime.Now;
                return result;
            }
            catch (Exception ex)
            {
                result.Success = false;
                result.Message = "关闭项目异常: " + ex.Message;
                result.CompletedAt = DateTime.Now;
                return result;
            }
        }

        public ExportIfcResult ExportIfc(ExportIfcRequest request)
        {
            var effectiveRequest = request ?? new ExportIfcRequest();
            effectiveRequest.ApplyDefaults();

            var result = new ExportIfcResult
            {
                StartedAt = DateTime.Now,
                ExportPath = effectiveRequest.ExportPath,
                FileName = effectiveRequest.FileName,
                FullPath = effectiveRequest.GetFullPath(),
                RequestedMdbName = effectiveRequest.MdbName,
                DriverMode = "macro-export"
            };

            try
            {
                if (!IsPdmsConnected())
                {
                    result.Success = false;
                    result.Message = "PDMS 未连接";
                    result.FailureCategory = "pdms-connection";
                    result.RawError = result.Message;
                    SetLastExportError(result.Message);
                    result.CompletedAt = DateTime.Now;
                    result.DurationSeconds = (result.CompletedAt - result.StartedAt).TotalSeconds;
                    return result;
                }

                string mdbValidationError;
                var currentMdb = ResolveExportMdb(effectiveRequest, result, out mdbValidationError);
                if (currentMdb == null)
                {
                    result.Success = false;
                    result.Message = mdbValidationError ?? "未找到可用于导出的MDB";
                    result.FailureCategory = "mdb-validation";
                    result.RawError = result.Message;
                    SetLastExportError(result.Message);
                    result.CompletedAt = DateTime.Now;
                    result.DurationSeconds = (result.CompletedAt - result.StartedAt).TotalSeconds;
                    return result;
                }

                result.ActiveMdbName = GetMdbNameSafe(currentMdb);
                result.BaseChecksPassed = true;

                var designDb = currentMdb?.GetFirstDB(DbType.Design);
                if (designDb == null || designDb.World == null)
                {
                    result.Success = false;
                    result.Message = "未找到有效的设计数据库";
                    result.FailureCategory = "design-db";
                    result.RawError = result.Message;
                    SetLastExportError(result.Message);
                    result.CompletedAt = DateTime.Now;
                    result.DurationSeconds = (result.CompletedAt - result.StartedAt).TotalSeconds;
                    return result;
                }

                // 确保导出目录存在
                if (!System.IO.Directory.Exists(effectiveRequest.ExportPath))
                {
                    System.IO.Directory.CreateDirectory(effectiveRequest.ExportPath);
                }

                // 执行PML命令 - 通过MacroCommand类型反射构造并执行
                var macroType = CommandManager.Instance.MacroCommand;
                if (macroType == null)
                    throw new InvalidOperationException("MacroCommand类型未注册");
                var ctor = macroType.GetConstructor(
                    System.Reflection.BindingFlags.Public |
                    System.Reflection.BindingFlags.NonPublic |
                    System.Reflection.BindingFlags.Instance,
                    null,
                    new[] { typeof(string), typeof(string), typeof(string) },
                    null);
                if (ctor == null)
                {
                    var ctors = macroType.GetConstructors(
                        System.Reflection.BindingFlags.Public |
                        System.Reflection.BindingFlags.NonPublic |
                        System.Reflection.BindingFlags.Instance);
                    var ctorInfo = new System.Text.StringBuilder();
                    foreach (var c in ctors)
                    {
                        ctorInfo.Append(c.ToString()).Append(" | ");
                    }

                    throw new InvalidOperationException(
                        "MacroCommand未找到(string,string,string)构造函数，类型: " + macroType.FullName + " 构造函数: " + ctorInfo);
                }

                var exportCommands = BuildExportCommands(effectiveRequest);
                for (int i = 0; i < exportCommands.Length; i++)
                {
                    result.ExecutedCommands.Add(exportCommands[i]);
                    var macroCommand = ctor.Invoke(new object[]
                    {
                        "TellmePdmsPluging.ExportIfc." + (i + 1),
                        exportCommands[i],
                        string.Empty
                    }) as Command;

                    if (macroCommand == null)
                    {
                        throw new InvalidOperationException("MacroCommand实例创建失败，类型: " + macroType.FullName);
                    }

                    macroCommand.Execute();
                }

                // 检查文件是否生成
                if (System.IO.File.Exists(result.FullPath))
                {
                    var fileInfo = new System.IO.FileInfo(result.FullPath);
                    result.FileSizeBytes = fileInfo.Length;
                    result.Success = true;
                    result.Message = "RVM导出成功";
                    result.FailureCategory = null;
                    result.RawError = null;
                    SetLastExportError(null);
                }
                else
                {
                    result.Success = false;
                    result.Message = "RVM导出失败，未生成文件";
                    result.FailureCategory = "output-path";
                    result.RawError = result.Message;
                    result.Diagnostics.Add("导出命令已执行，但目标文件未生成");
                    SetLastExportError(result.Message);
                }

                result.CompletedAt = DateTime.Now;
                result.DurationSeconds = (result.CompletedAt - result.StartedAt).TotalSeconds;
                return result;
            }
            catch (Exception ex)
            {
                result.Success = false;
                result.RawError = ex.Message;
                result.FailureCategory = ClassifyExportFailure(ex.Message);
                result.Message = TranslateExportException(ex, result.ActiveMdbName, effectiveRequest.MdbName);
                result.Diagnostics.Add("导出命令执行失败，分类=" + result.FailureCategory);
                SetLastExportError(result.Message);
                result.CompletedAt = DateTime.Now;
                result.DurationSeconds = (result.CompletedAt - result.StartedAt).TotalSeconds;
                return result;
            }
        }

        private ExportDiagnostics GetExportDiagnostics(string requestedMdbName)
        {
            var diagnostics = new ExportDiagnostics
            {
                RequestedMdbName = NormalizeMdbName(requestedMdbName),
                LastExportError = _lastExportErrorMessage
            };

            try
            {
                var currentMdb = MDB.CurrentMDB;
                diagnostics.ActiveMdbName = GetMdbNameSafe(currentMdb);
                diagnostics.CurrentMdbMatchesRequested = string.IsNullOrEmpty(diagnostics.RequestedMdbName) ||
                                                        IsSameMdbName(diagnostics.ActiveMdbName, diagnostics.RequestedMdbName);

                var designDb = currentMdb == null ? null : currentMdb.GetFirstDB(DbType.Design);
                diagnostics.DesignDbAvailable = designDb != null && designDb.World != null;
                diagnostics.DefinitionsLikelyMissing = IsDefinitionsError(_lastExportErrorMessage);

                if (currentMdb == null)
                {
                    diagnostics.ExportPrecheckPassed = false;
                    diagnostics.Message = "当前没有活动MDB";
                    return diagnostics;
                }

                if (!diagnostics.CurrentMdbMatchesRequested)
                {
                    diagnostics.ExportPrecheckPassed = false;
                    diagnostics.Message = "当前活动MDB与请求的MDB不一致";
                    return diagnostics;
                }

                if (!diagnostics.DesignDbAvailable)
                {
                    diagnostics.ExportPrecheckPassed = false;
                    diagnostics.Message = "当前MDB未挂接有效的Design DB";
                    return diagnostics;
                }

                if (diagnostics.DefinitionsLikelyMissing)
                {
                    diagnostics.ExportPrecheckPassed = false;
                    diagnostics.Message = "当前MDB疑似缺少导出所需的UDET/UDA definitions";
                    return diagnostics;
                }

                diagnostics.ExportPrecheckPassed = true;
                diagnostics.Message = "导出前置检查通过";
                return diagnostics;
            }
            catch (Exception ex)
            {
                diagnostics.ExportPrecheckPassed = false;
                diagnostics.Message = "导出检查异常: " + ex.Message;
                return diagnostics;
            }
        }

        private MDB ResolveExportMdb(ExportIfcRequest request, ExportIfcResult result, out string error)
        {
            error = null;

            try
            {
                var currentMdb = MDB.CurrentMDB;
                var requestedMdbName = NormalizeMdbName(request.MdbName);
                request.MdbName = requestedMdbName;
                result.RequestedMdbName = requestedMdbName;
                result.ActiveMdbName = GetMdbNameSafe(currentMdb);

                if (string.IsNullOrEmpty(requestedMdbName))
                {
                    result.UsedRequestedMdb = false;
                    result.Diagnostics.Add("未提供mdbName，直接使用当前活动MDB");
                    return currentMdb;
                }

                if (currentMdb != null && IsSameMdbName(currentMdb.Name, requestedMdbName))
                {
                    result.UsedRequestedMdb = true;
                    result.Diagnostics.Add("请求的MDB与当前活动MDB一致，直接使用当前MDB");
                    return currentMdb;
                }

                result.UsedRequestedMdb = false;
                result.Diagnostics.Add("请求的MDB与当前活动MDB不一致，插件不会自动切换MDB");
                error = "当前活动MDB " + (GetMdbNameSafe(currentMdb) ?? "NULL") + " 与请求的MDB " + requestedMdbName + " 不一致，请先在PDMS中手动切换后重试";
                return null;
            }
            catch (Exception ex)
            {
                error = "校验导出MDB异常: " + ex.Message;
                return null;
            }
        }

        private static string GetMdbNameSafe(MDB mdb)
        {
            if (mdb == null)
            {
                return null;
            }

            try
            {
                return mdb.Name;
            }
            catch
            {
                return null;
            }
        }

        private static string NormalizeMdbName(string value)
        {
            if (string.IsNullOrEmpty(value))
            {
                return null;
            }

            var trimmed = value.Trim();
            if (trimmed.Length == 0)
            {
                return null;
            }

            if (!trimmed.StartsWith("/", StringComparison.Ordinal))
            {
                trimmed = "/" + trimmed.TrimStart('/');
            }

            return trimmed;
        }

        private static bool IsSameMdbName(string left, string right)
        {
            var normalizedLeft = NormalizeMdbName(left);
            var normalizedRight = NormalizeMdbName(right);

            if (string.IsNullOrEmpty(normalizedLeft) || string.IsNullOrEmpty(normalizedRight))
            {
                return false;
            }

            return string.Equals(normalizedLeft, normalizedRight, StringComparison.OrdinalIgnoreCase);
        }

        private static string TranslateExportException(Exception ex, string activeMdbName, string requestedMdbName)
        {
            var rawMessage = ex == null ? string.Empty : ex.Message ?? string.Empty;
            var mdbName = !string.IsNullOrEmpty(activeMdbName) ? activeMdbName : requestedMdbName;

            if (IsDefinitionsError(rawMessage))
            {
                if (!string.IsNullOrEmpty(mdbName))
                {
                    return "RVM导出失败: 当前MDB " + mdbName + " 缺少导出所需的UDET/UDA定义，请切换到包含定义库的MDB后重试";
                }

                return "RVM导出失败: 当前MDB缺少导出所需的UDET/UDA定义，请切换到包含定义库的MDB后重试";
            }

            if (rawMessage.IndexOf("找不到文件", StringComparison.OrdinalIgnoreCase) >= 0 ||
                rawMessage.IndexOf("could not find file", StringComparison.OrdinalIgnoreCase) >= 0)
            {
                return "RVM导出失败: Review driver/template 路径或输入文件无效";
            }

            return "RVM导出异常: " + rawMessage;
        }

        private static string ClassifyExportFailure(string rawMessage)
        {
            if (string.IsNullOrEmpty(rawMessage))
            {
                return "command";
            }

            if (IsDefinitionsError(rawMessage))
            {
                return "definitions";
            }

            if (rawMessage.IndexOf("找不到文件", StringComparison.OrdinalIgnoreCase) >= 0 ||
                rawMessage.IndexOf("could not find file", StringComparison.OrdinalIgnoreCase) >= 0)
            {
                return "driver-template";
            }

            if (rawMessage.IndexOf("应用程序中的错误", StringComparison.OrdinalIgnoreCase) >= 0)
            {
                return "mdb-switch";
            }

            return "command";
        }

        private static bool IsDefinitionsError(string message)
        {
            if (string.IsNullOrEmpty(message))
            {
                return false;
            }

            return message.IndexOf("Undefined UDA or UDET name", StringComparison.OrdinalIgnoreCase) >= 0;
        }

        private static void SetLastExportError(string message)
        {
            _lastExportErrorMessage = message;
        }

        private string[] BuildExportCommands(ExportIfcRequest request)
        {
            // 按文档流程构建命令：
            // EXPORT SYSTEM <driver> (可选)
            // EXPORT FILE <name> OVERWRITE
            // EXPORT <selection>
            // EXPORT FINISH
            string fullPath = request.GetFullPath().Replace("\\", "/");
            var commands = new List<string>();

            if (!string.IsNullOrEmpty(request.ExportSystem))
            {
                commands.Add("EXPORT SYSTEM " + request.ExportSystem);
            }

            commands.Add(string.Format("EXPORT FILE {0} {1}", fullPath, request.Overwrite.GetValueOrDefault(true) ? "OVERWRITE" : "READ"));

            var selections = request.GetEffectiveSelections();
            foreach (var selectionCommand in selections)
            {
                commands.Add(selectionCommand);
            }

            commands.Add("EXPORT FINISH");

            return commands.ToArray();
        }

        public OpenMdbResult OpenMdb(OpenMdbRequest request)
        {
            var effectiveRequest = request ?? new OpenMdbRequest();
            effectiveRequest.ApplyDefaults();

            var result = new OpenMdbResult
            {
                MdbName = effectiveRequest.MdbName,
                ReadOnly = effectiveRequest.ReadOnly,
                DefaultType = effectiveRequest.DefaultType,
                FileSize = -1,
                PolygonCount = -1,
                FeatureCount = -1,
                CompletedAt = DateTime.Now
            };

            try
            {
                if (string.IsNullOrEmpty(effectiveRequest.MdbName))
                {
                    result.Success = false;
                    result.Message = "MdbName 不能为空";
                    return result;
                }

                // 如果当前MDB已经是目标，则直接返回成功
                try
                {
                    var current = MDB.CurrentMDB;
                    if (current != null && string.Equals(current.Name, effectiveRequest.MdbName, StringComparison.OrdinalIgnoreCase))
                    {
                        result.Success = true;
                        result.WasAlreadyOpen = true;
                        result.Message = "MDB 已经打开";
                        PopulateOpenMdbMetrics(result);
                        result.CompletedAt = DateTime.Now;
                        return result;
                    }
                }
                catch
                {
                    // ignore, continue to open
                }

                var setup = MDBSetup.CreateMDBSetup(effectiveRequest.MdbName);
                if (setup == null)
                {
                    result.Success = false;
                    result.Message = "创建 MDBSetup 失败";
                    return result;
                }

                setup.ReadOnly = effectiveRequest.ReadOnly;

                if (effectiveRequest.Subtype.HasValue)
                {
                    setup.Subtype = effectiveRequest.Subtype.Value;
                }

                if (!string.IsNullOrEmpty(effectiveRequest.DefaultType))
                {
                    DbType defaultType;
                    if (!TryParseDbType(effectiveRequest.DefaultType, out defaultType))
                    {
                        result.Success = false;
                        result.Message = "DefaultType 无效: " + effectiveRequest.DefaultType;
                        return result;
                    }
                    setup.DefaultType = defaultType;
                }

                if (effectiveRequest.ReadTypes != null && effectiveRequest.ReadTypes.Count > 0)
                {
                    DbType[] readTypes;
                    string error;
                    if (!TryParseDbTypes(effectiveRequest.ReadTypes, out readTypes, out error))
                    {
                        result.Success = false;
                        result.Message = "ReadTypes 无效: " + error;
                        return result;
                    }
                    setup.ReadTypes = readTypes;
                }

                if (effectiveRequest.WriteTypes != null && effectiveRequest.WriteTypes.Count > 0)
                {
                    DbType[] writeTypes;
                    string error;
                    if (!TryParseDbTypes(effectiveRequest.WriteTypes, out writeTypes, out error))
                    {
                        result.Success = false;
                        result.Message = "WriteTypes 无效: " + error;
                        return result;
                    }
                    setup.WriteTypes = writeTypes;
                }

                var openedMdb = Project.OpenMDB(setup);
                if (openedMdb == null)
                {
                    result.Success = false;
                    result.Message = "打开 MDB 失败（OpenMDB 返回 null）";
                    result.CompletedAt = DateTime.Now;
                    return result;
                }

                result.Success = true;
                result.WasAlreadyOpen = false;
                result.MdbName = openedMdb.Name;
                result.Message = "MDB 打开成功";
                PopulateOpenMdbMetrics(result);
                result.CompletedAt = DateTime.Now;
                return result;
            }
            catch (Exception ex)
            {
                result.Success = false;
                result.Message = "打开 MDB 异常: " + ex.Message;
                result.CompletedAt = DateTime.Now;
                return result;
            }
        }

        private static bool TryParseDbTypes(IEnumerable<string> values, out DbType[] types, out string error)
        {
            var list = new List<DbType>();
            var invalid = new List<string>();

            foreach (var raw in values)
            {
                if (string.IsNullOrEmpty(raw))
                {
                    continue;
                }

                DbType parsed;
                if (TryParseDbType(raw, out parsed))
                {
                    if (!list.Contains(parsed))
                    {
                        list.Add(parsed);
                    }
                }
                else
                {
                    invalid.Add(raw);
                }
            }

            if (invalid.Count > 0)
            {
                types = null;
                error = string.Join(",", invalid.ToArray());
                return false;
            }

            types = list.ToArray();
            error = null;
            return true;
        }

        private static bool TryParseDbType(string value, out DbType dbType)
        {
            dbType = DbType.Design;
            if (string.IsNullOrEmpty(value))
            {
                return false;
            }

            try
            {
                dbType = (DbType)Enum.Parse(typeof(DbType), value.Trim(), true);
                return true;
            }
            catch
            {
                return false;
            }
        }

        private static string GetProjectNameSafe(Project project)
        {
            if (project == null)
            {
                return null;
            }

            try
            {
                var nameProperty = project.GetType().GetProperty("Name");
                if (nameProperty != null)
                {
                    var value = nameProperty.GetValue(project, null) as string;
                    if (!string.IsNullOrEmpty(value))
                    {
                        return value;
                    }
                }
            }
            catch
            {
                // ignore and fallback
            }

            return null;
        }

        private static bool IsDbReadOnly(Db db)
        {
            if (db == null)
            {
                return true;
            }

            try
            {
                var property = db.GetType().GetProperty("IsReadOnly");
                if (property == null)
                {
                    return false;
                }

                var value = property.GetValue(db, null);
                if (value is bool)
                {
                    return (bool)value;
                }
            }
            catch
            {
                // ignore and treat as writable
            }

            return false;
        }

        private static bool TryPersistCurrentMdbChanges(string comment, out string error)
        {
            error = null;
            try
            {
                var mdb = MDB.CurrentMDB;
                if (mdb == null)
                {
                    error = "当前MDB为空";
                    return false;
                }

                bool saveResult;
                if (TryInvokeSaveWorkByComment(mdb, comment, out saveResult))
                {
                    if (saveResult)
                    {
                        return true;
                    }

                    error = "SaveWork(string) 返回 false";
                    return false;
                }

                var designDb = mdb.GetFirstDB(DbType.Design);
                if (designDb == null)
                {
                    error = "未找到Design DB";
                    return false;
                }

                if (IsDbReadOnly(designDb))
                {
                    error = "Design DB为只读";
                    return false;
                }

                if (TryInvokeSaveWorkByDbs(mdb, new[] { designDb }, comment, out saveResult))
                {
                    if (saveResult)
                    {
                        return true;
                    }

                    error = "SaveWork(Db[], string) 返回 false";
                    return false;
                }

                error = "未找到可用的SaveWork重载";
                return false;
            }
            catch (Exception ex)
            {
                error = ex.Message;
                return false;
            }
        }

        private static bool TryPersistCurrentMdbChanges(string comment, IList<Db> touchedDbs, IList<string> processedDbNames, out string error)
        {
            error = null;

            if (processedDbNames != null)
            {
                processedDbNames.Clear();
            }

            try
            {
                var mdb = MDB.CurrentMDB;
                if (mdb == null)
                {
                    error = "当前MDB为空";
                    return false;
                }

                var writableDbs = new List<Db>();
                if (touchedDbs != null)
                {
                    for (int i = 0; i < touchedDbs.Count; i++)
                    {
                        var db = touchedDbs[i];
                        if (db == null || IsDbReadOnly(db))
                        {
                            continue;
                        }

                        if (!ContainsDb(writableDbs, db))
                        {
                            writableDbs.Add(db);
                            if (processedDbNames != null)
                            {
                                processedDbNames.Add(GetDbNameSafe(db));
                            }
                        }
                    }
                }

                if (writableDbs.Count > 0)
                {
                    bool saveResult;
                    if (TryInvokeSaveWorkByDbs(mdb, writableDbs.ToArray(), comment, out saveResult))
                    {
                        if (saveResult)
                        {
                            return true;
                        }

                        error = "SaveWork(Db[], string) 返回 false";
                        return false;
                    }
                }

                return TryPersistCurrentMdbChanges(comment, out error);
            }
            catch (Exception ex)
            {
                error = ex.Message;
                return false;
            }
        }

        private static bool TryInvokeSaveWorkByComment(MDB mdb, string comment, out bool saveResult)
        {
            saveResult = false;
            try
            {
                var method = mdb.GetType().GetMethod("SaveWork", new[] { typeof(string) });
                if (method == null)
                {
                    return false;
                }

                var result = method.Invoke(mdb, new object[] { comment ?? string.Empty });
                saveResult = !(result is bool) || (bool)result;
                return true;
            }
            catch
            {
                return false;
            }
        }

        private static bool TryInvokeSaveWorkByDbs(MDB mdb, Db[] dbs, string comment, out bool saveResult)
        {
            saveResult = false;
            try
            {
                var method = mdb.GetType().GetMethod("SaveWork", new[] { typeof(Db[]), typeof(string) });
                if (method == null)
                {
                    return false;
                }

                var result = method.Invoke(mdb, new object[] { dbs, comment ?? string.Empty });
                saveResult = !(result is bool) || (bool)result;
                return true;
            }
            catch
            {
                return false;
            }
        }

        private static bool ContainsDb(IList<Db> dbs, Db candidate)
        {
            if (dbs == null || candidate == null)
            {
                return false;
            }

            for (int i = 0; i < dbs.Count; i++)
            {
                if (object.ReferenceEquals(dbs[i], candidate))
                {
                    return true;
                }
            }

            return false;
        }

        private bool IsPdmsConnected()
        {
            try
            {
                // 使用MDB.CurrentMDB检查PDMS连接状态
                var currentMdb = MDB.CurrentMDB;
                return currentMdb != null;
            }
            catch
            {
                return false;
            }
        }

        private ProjectInfo GetProjectInfo()
        {
            try
            {
                // 使用MDB.CurrentMDB和Project.CurrentProject获取真实项目信息
                var currentMdb = MDB.CurrentMDB;
                var currentProject = Project.CurrentProject;
                
                if (currentMdb != null)
                {
                    var designDb = currentMdb.GetFirstDB(DbType.Design);
                    if (designDb != null)
                    {
                        return new ProjectInfo
                        {
                            ProjectName = designDb.Name ?? "Unknown",
                            MdsName = currentMdb.Name ?? "Unknown", 
                            PdmsVersion = "12.1.SP4"
                        };
                    }
                }
                
                return new ProjectInfo
                {
                    ProjectName = "Unknown",
                    MdsName = "Unknown", 
                    PdmsVersion = "12.1.SP4"
                };
            }
            catch (Exception ex)
            {
                System.Diagnostics.Debug.WriteLine($"获取项目信息失败: {ex.Message}");
                return new ProjectInfo
                {
                    ProjectName = "Unknown",
                    MdsName = "Unknown",
                    PdmsVersion = "12.1.SP4"
                };
            }
        }



        private ModelStatistics GetModelStatistics()
        {
            try
            {
                // 使用MDB.CurrentMDB获取真实模型统计信息
                var currentMdb = MDB.CurrentMDB;
                if (currentMdb != null)
                {
                    var designDb = currentMdb.GetFirstDB(DbType.Design);
                    if (designDb?.World != null)
                    {
                        // 初始化统计计数器
                        var elementCounts = new Dictionary<string, int>
                        {
                            {"SITE", 0}, {"ZONE", 0}, {"PIPE", 0}, {"EQUI", 0},
                            {"STRU", 0}, {"VALVE", 0}, {"FITT", 0}, {"NOZZ", 0}
                        };

                        int totalElements = 0;
                        var activeZones = new List<string>();
                        int zoneCount = 0;

                        // 递归统计所有元素
                        CountElementsByType(designDb.World, elementCounts, ref totalElements);

                        // 专门统计Zone信息
                        CountZones(designDb.World, ref zoneCount, activeZones);

                        return new ModelStatistics
                        {
                            TotalElements = totalElements,
                            ElementCounts = elementCounts,
                            ZoneCount = zoneCount,
                            ActiveZones = activeZones,
                            FileSize = TryGetCurrentModelFileSize(),
                            PolygonCount = -1,
                            FeatureCount = totalElements
                        };
                    }
                }

                return new ModelStatistics
                {
                    TotalElements = 0,
                    ElementCounts = new Dictionary<string, int>(),
                    ZoneCount = 0,
                    ActiveZones = new List<string>(),
                    FileSize = -1,
                    PolygonCount = -1,
                    FeatureCount = 0
                };
            }
            catch (Exception ex)
            {
                System.Diagnostics.Debug.WriteLine($"获取模型统计信息失败: {ex.Message}");
                return new ModelStatistics
                {
                    TotalElements = 0,
                    ElementCounts = new Dictionary<string, int>(),
                    ZoneCount = 0,
                    ActiveZones = new List<string>(),
                    FileSize = -1,
                    PolygonCount = -1,
                    FeatureCount = 0
                };
            }
        }

        private void PopulateOpenProjectMetrics(OpenProjectResult result)
        {
            var statistics = GetModelStatistics();
            if (statistics == null)
            {
                return;
            }

            result.FileSize = statistics.FileSize;
            result.PolygonCount = statistics.PolygonCount;
            result.FeatureCount = statistics.FeatureCount;
        }

        private void PopulateOpenMdbMetrics(OpenMdbResult result)
        {
            var statistics = GetModelStatistics();
            if (statistics == null)
            {
                return;
            }

            result.FileSize = statistics.FileSize;
            result.PolygonCount = statistics.PolygonCount;
            result.FeatureCount = statistics.FeatureCount;
        }

        private long TryGetCurrentModelFileSize()
        {
            try
            {
                var currentMdb = MDB.CurrentMDB;
                if (currentMdb == null)
                {
                    return -1;
                }

                var designDb = currentMdb.GetFirstDB(DbType.Design);
                string path = TryGetCandidatePath(designDb) ?? TryGetCandidatePath(currentMdb);
                if (string.IsNullOrEmpty(path) || !System.IO.File.Exists(path))
                {
                    return -1;
                }

                return new System.IO.FileInfo(path).Length;
            }
            catch
            {
                return -1;
            }
        }

        private static string TryGetCandidatePath(object source)
        {
            if (source == null)
            {
                return null;
            }

            var type = source.GetType();
            var names = new[] { "FileName", "Filename", "FullName", "Path" };
            foreach (var name in names)
            {
                var prop = type.GetProperty(name);
                if (prop != null && prop.PropertyType == typeof(string))
                {
                    var value = prop.GetValue(source, null) as string;
                    if (LooksLikeFilePath(value))
                    {
                        return value;
                    }
                }

                var field = type.GetField(name);
                if (field != null && field.FieldType == typeof(string))
                {
                    var value = field.GetValue(source) as string;
                    if (LooksLikeFilePath(value))
                    {
                        return value;
                    }
                }
            }

            return null;
        }

        private static bool LooksLikeFilePath(string value)
        {
            if (string.IsNullOrEmpty(value))
            {
                return false;
            }

            var trimmed = value.Trim();
            if (trimmed.Length < 3)
            {
                return false;
            }

            return trimmed.IndexOf('\\') >= 0 || trimmed.IndexOf('/') >= 0;
        }

        private void CountElementsByType(DbElement parentElement, Dictionary<string, int> elementCounts, ref int totalElements)
        {
            try
            {
                if (parentElement == null || parentElement.IsNull || !parentElement.IsValid)
                    return;

                // 获取所有子元素
                var members = parentElement.Members();
                if (members != null)
                {
                    foreach (var element in members)
                    {
                        if (element != null && !element.IsNull && element.IsValid)
                        {
                            totalElements++;

                            // 获取元素的实际类型
                            var elementType = element.GetActualType();
                            if (elementType != null)
                            {
                                string typeName = elementType.Name;
                                if (elementCounts.ContainsKey(typeName))
                                {
                                    elementCounts[typeName]++;
                                }
                            }

                            // 递归统计子元素
                            CountElementsByType(element, elementCounts, ref totalElements);
                        }
                    }
                }
            }
            catch (Exception ex)
            {
                System.Diagnostics.Debug.WriteLine($"统计元素类型时出错: {ex.Message}");
            }
        }

        private void CountZones(DbElement worldElement, ref int zoneCount, List<string> activeZones)
        {
            try
            {
                if (worldElement == null || worldElement.IsNull || !worldElement.IsValid)
                    return;

                // 查找SITE元素
                var sites = worldElement.Members();
                if (sites != null)
                {
                    foreach (var site in sites)
                    {
                        if (site != null && !site.IsNull && site.IsValid)
                        {
                            var siteType = site.GetActualType();
                            if (siteType != null && siteType.Name == "SITE")
                            {
                                // 在SITE下查找ZONE元素
                                var zones = site.Members();
                                if (zones != null)
                                {
                                    foreach (var zone in zones)
                                    {
                                        if (zone != null && !zone.IsNull && zone.IsValid)
                                        {
                                            var zoneType = zone.GetActualType();
                                            if (zoneType != null && zoneType.Name == "ZONE")
                                            {
                                                zoneCount++;

                                                // 获取Zone名称
                                                try
                                                {
                                                    string zoneName = "";
                                                    if (zone.GetValidString(DbAttributeInstance.NAME, ref zoneName))
                                                    {
                                                        if (!string.IsNullOrEmpty(zoneName))
                                                        {
                                                            activeZones.Add(zoneName);
                                                        }
                                                    }
                                                }
                                                catch
                                                {
                                                    // 如果无法获取名称，跳过
                                                }
                                            }
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
            }
            catch (Exception ex)
            {
                System.Diagnostics.Debug.WriteLine($"统计Zone信息时出错: {ex.Message}");
            }
        }

        private SessionInfo GetSessionInfo()
        {
            try
            {
                // 使用MDB.CurrentMDB获取真实会话信息
                var currentMdb = MDB.CurrentMDB;
                if (currentMdb != null)
                {
                    var designDb = currentMdb.GetFirstDB(DbType.Design);
                    if (designDb?.CurrentSession != null)
                    {
                        // 从真实的数据库会话获取信息
                        var session = designDb.CurrentSession;
                        return new SessionInfo
                        {
                            UserName = session.User ?? Environment.UserName, // 从DbSession获取用户名
                            StartTime = session.Date, // 从DbSession获取会话创建时间
                            DurationMinutes = (int)(DateTime.Now - session.Date).TotalMinutes // 计算会话持续时间
                        };
                    }
                }
                
                return new SessionInfo
                {
                    UserName = Environment.UserName,
                    StartTime = DateTime.Now,
                    DurationMinutes = 0
                };
            }
            catch (Exception ex)
            {
                System.Diagnostics.Debug.WriteLine($"获取会话信息失败: {ex.Message}");
                return new SessionInfo
                {
                    UserName = Environment.UserName,
                    StartTime = DateTime.Now,
                    DurationMinutes = 0
                };
            }
        }
        private static bool IsElementValid(DbElement element)
        {
            return element != null && !element.IsNull && element.IsValid;
        }

        private static string GetElementTypeName(DbElement element)
        {
            try
            {
                var type = element?.GetActualType();
                return type?.Name ?? string.Empty;
            }
            catch
            {
                return string.Empty;
            }
        }

        private static string BuildElementPath(DbElement element)
        {
            var segments = new List<string>();
            var current = element;
            int guard = 0;

            while (IsElementValid(current) && guard < 128)
            {
                string name = string.Empty;
                try
                {
                    if (!current.GetValidString(DbAttributeInstance.NAME, ref name) || string.IsNullOrEmpty(name))
                    {
                        name = current.ToString();
                    }
                }
                catch
                {
                    name = current.ToString();
                }

                segments.Add(name.Trim());
                current = current.Owner;
                guard++;
            }

            segments.Reverse();
            return "/" + string.Join("/", segments.ToArray());
        }

        private static bool TryGetElementDb(DbElement element, out Db db)
        {
            db = null;
            if (!IsElementValid(element))
            {
                return false;
            }

            var names = new[] { "DB", "Db", "Database", "OwningDB", "OwnerDB" };
            var type = element.GetType();

            for (int i = 0; i < names.Length; i++)
            {
                var prop = type.GetProperty(names[i]);
                if (prop != null && typeof(Db).IsAssignableFrom(prop.PropertyType))
                {
                    try
                    {
                        db = prop.GetValue(element, null) as Db;
                        if (db != null)
                        {
                            return true;
                        }
                    }
                    catch
                    {
                        // ignore
                    }
                }
            }

            return false;
        }

        private static string GetDbNameSafe(Db db)
        {
            if (db == null)
            {
                return "UNKNOWN_DB";
            }

            try
            {
                return db.Name ?? db.ToString();
            }
            catch
            {
                return "UNKNOWN_DB";
            }
        }

        private static bool IsDesignDb(Db db)
        {
            if (db == null)
            {
                return false;
            }

            try
            {
                var property = db.GetType().GetProperty("Type");
                if (property == null)
                {
                    return false;
                }

                var value = property.GetValue(db, null);
                if (value is DbType)
                {
                    return (DbType)value == DbType.Design;
                }
            }
            catch
            {
                // ignore
            }

            return false;
        }

        private static bool IsElementUnderOwner(DbElement element, DbElement expectedOwner)
        {
            if (!IsElementValid(element) || !IsElementValid(expectedOwner))
            {
                return false;
            }

            var current = element;
            int guard = 0;
            while (IsElementValid(current) && guard < 512)
            {
                if (object.ReferenceEquals(current, expectedOwner))
                {
                    return true;
                }

                current = current.Owner;
                guard++;
            }

            return false;
        }

        private static bool ShouldSkipLinkedElement(DbElement element, bool skipLinkedElements, out string reason)
        {
            reason = null;

            if (!skipLinkedElements || !IsElementValid(element))
            {
                return false;
            }

            try
            {
                if (!element.IsDeleteable)
                {
                    reason = "IsDeleteable=false";
                    return true;
                }
            }
            catch
            {
                // ignore
            }

            string attributeName;
            string attributeValue;
            if (TryFindLinkedAttributeValue(element, out attributeName, out attributeValue))
            {
                reason = string.IsNullOrEmpty(attributeValue)
                    ? attributeName
                    : (attributeName + "=" + attributeValue);
                return true;
            }

            return false;
        }

        private static bool TryFindLinkedAttributeValue(DbElement element, out string attributeName, out string attributeValue)
        {
            attributeName = null;
            attributeValue = null;

            if (!IsElementValid(element))
            {
                return false;
            }

            foreach (var candidate in LinkedAttributeCandidates)
            {
                DbAttribute attribute;
                if (!TryGetDbAttributeByName(candidate, out attribute) || attribute == null)
                {
                    continue;
                }

                bool isValid;
                try
                {
                    isValid = element.IsAttributeValid(attribute);
                }
                catch
                {
                    continue;
                }

                if (!isValid)
                {
                    continue;
                }

                string textValue = string.Empty;
                try
                {
                    if (element.GetValidAsString(attribute, ref textValue) && HasMeaningfulLinkedValue(textValue))
                    {
                        attributeName = candidate;
                        attributeValue = SummarizeValue(textValue);
                        return true;
                    }
                }
                catch
                {
                    // ignore and fallback to array check
                }

                try
                {
                    var refs = element.GetElementArray(attribute);
                    if (refs != null)
                    {
                        for (int i = 0; i < refs.Length; i++)
                        {
                            if (IsElementValid(refs[i]))
                            {
                                attributeName = candidate;
                                attributeValue = "REFS>0";
                                return true;
                            }
                        }
                    }
                }
                catch
                {
                    // ignore
                }
            }

            return false;
        }

        private static bool TryGetDbAttributeByName(string name, out DbAttribute attribute)
        {
            attribute = null;
            if (string.IsNullOrEmpty(name))
            {
                return false;
            }

            lock (_attributeCacheLock)
            {
                if (_attributeCache.TryGetValue(name, out attribute))
                {
                    return attribute != null;
                }
            }

            DbAttribute resolved = null;
            try
            {
                var flags = System.Reflection.BindingFlags.Public |
                            System.Reflection.BindingFlags.Static |
                            System.Reflection.BindingFlags.IgnoreCase;

                var field = typeof(DbAttributeInstance).GetField(name, flags);
                if (field != null)
                {
                    resolved = field.GetValue(null) as DbAttribute;
                }

                if (resolved == null)
                {
                    var property = typeof(DbAttributeInstance).GetProperty(name, flags);
                    if (property != null)
                    {
                        resolved = property.GetValue(null, null) as DbAttribute;
                    }
                }
            }
            catch
            {
                resolved = null;
            }

            lock (_attributeCacheLock)
            {
                _attributeCache[name] = resolved;
            }

            attribute = resolved;
            return attribute != null;
        }

        private static bool HasMeaningfulLinkedValue(string value)
        {
            if (IsNullOrWhiteSpace(value))
            {
                return false;
            }

            var normalized = value.Trim().ToUpperInvariant();
            switch (normalized)
            {
                case "0":
                case "FALSE":
                case "NONE":
                case "NO":
                case "NULREF":
                case "NULL":
                case "UNSET":
                case "UNDEFINED":
                case "[]":
                case "{}":
                    return false;
            }

            if (normalized.IndexOf("NULREF", StringComparison.Ordinal) >= 0 ||
                normalized.IndexOf("UNSET", StringComparison.Ordinal) >= 0 ||
                normalized.IndexOf("UNDEFINED", StringComparison.Ordinal) >= 0)
            {
                return false;
            }

            bool hasLetter = false;
            bool hasSlash = false;
            for (int i = 0; i < normalized.Length; i++)
            {
                char ch = normalized[i];
                if (char.IsLetter(ch))
                {
                    hasLetter = true;
                    break;
                }
                if (ch == '/')
                {
                    hasSlash = true;
                }
            }

            if (!hasLetter && !hasSlash)
            {
                return false;
            }

            return true;
        }

        private static string SummarizeValue(string value)
        {
            if (string.IsNullOrEmpty(value))
            {
                return value;
            }

            var trimmed = value.Trim();
            const int maxLength = 64;
            if (trimmed.Length <= maxLength)
            {
                return trimmed;
            }

            return trimmed.Substring(0, maxLength) + "...";
        }

        private static bool IsNullOrWhiteSpace(string value)
        {
            if (value == null)
            {
                return true;
            }

            for (int i = 0; i < value.Length; i++)
            {
                if (!char.IsWhiteSpace(value[i]))
                {
                    return false;
                }
            }

            return true;
        }

        private class SimplifyContext
        {
            private const int MaxRemovedSnapshots = 200;
            private const int MaxSkippedSnapshots = 200;

            public SimplifyContext(SimplifyModelRequest request, SimplifyModelResult result)
            {
                Request = request;
                Result = result;
                _keepTypes = new HashSet<string>(request.KeepTypes ?? new List<string>());
                _removeTypes = new HashSet<string>(request.RemoveTypes ?? new List<string>());
            }

            public SimplifyModelRequest Request { get; }
            public SimplifyModelResult Result { get; }
            public string CurrentZoneName { get; private set; }

            private readonly HashSet<string> _keepTypes;
            private readonly HashSet<string> _removeTypes;

            public bool ShouldProcessZone(DbElement zone)
            {
                if (Request.ZoneFilters == null || Request.ZoneFilters.Count == 0)
                {
                    return true;
                }

                var zonePath = BuildElementPath(zone).ToUpperInvariant();
                return Request.ZoneFilters.Any(filter => zonePath.Contains(filter));
            }

            public void EnterZone(DbElement zone)
            {
                CurrentZoneName = BuildElementPath(zone);
                if (!Result.ZoneSummaries.Contains(CurrentZoneName))
                {
                    Result.ZoneSummaries.Add(CurrentZoneName);
                }
            }

            public void ProcessChildren(DbElement parent)
            {
                var members = parent.Members();
                if (members == null)
                {
                    return;
                }

                foreach (var child in members)
                {
                    ProcessElement(child);
                }
            }

            private void ProcessElement(DbElement element)
            {
                if (!IsElementValid(element))
                {
                    return;
                }

                Result.TotalVisited++;
                var typeName = GetElementTypeName(element);
                var normalizedType = string.IsNullOrEmpty(typeName) ? string.Empty : typeName.ToUpperInvariant();

                bool keep = _keepTypes.Contains(normalizedType);
                bool remove = _removeTypes.Contains(normalizedType) && !keep;

                if (remove)
                {
                    RemoveElement(element, normalizedType);
                    return;
                }

                Result.KeptCount++;
                ProcessChildren(element);
            }

            private void RemoveElement(DbElement element, string typeName)
            {
                var elementPath = BuildElementPath(element);

                try
                {
                    string linkedReason;
                    if (ShouldSkipLinkedElement(element, Request.SkipLinkedElements, out linkedReason))
                    {
                        Result.KeptCount++;
                        SnapshotSkipped(elementPath, typeName, linkedReason);
                        return;
                    }

                    if (Request.DryRun)
                    {
                        SnapshotRemoval(elementPath, typeName, true);
                        return;
                    }

                    element.Delete();
                    SnapshotRemoval(elementPath, typeName, false);
                }
                catch (Exception ex)
                {
                    Result.Errors.Add($"删除元素 {elementPath} 失败: {ex.Message}");
                }
            }

            private void SnapshotRemoval(string elementPath, string typeName, bool dryRun)
            {
                Result.RemovedCount++;

                if (Result.RemovedElements.Count < MaxRemovedSnapshots)
                {
                    Result.RemovedElements.Add((dryRun ? "[DRYRUN-DEL] " : "[DEL] ") + elementPath + " (" + typeName + ")");
                }
            }

            private void SnapshotSkipped(string elementPath, string typeName, string reason)
            {
                Result.SkippedLinkedCount++;

                if (Result.SkippedLinkedElements.Count < MaxSkippedSnapshots)
                {
                    var suffix = string.IsNullOrEmpty(reason) ? string.Empty : (" [" + reason + "]");
                    Result.SkippedLinkedElements.Add("[SKIP-LINKED] " + elementPath + " (" + typeName + ")" + suffix);
                }
            }
        }

        private class ShrinkwrapContext
        {
            private const int MaxRemovedSnapshots = 200;
            private const int MaxSkippedSnapshots = 200;
            private const float MinBoxEdge = 0.001f;
            private readonly List<Db> _touchedWritableDbs;

            public ShrinkwrapContext(ShrinkwrapModelRequest request, ShrinkwrapModelResult result)
            {
                Request = request;
                Result = result;
                _keepTypes = new HashSet<string>(request.KeepTypes ?? new List<string>());
                _shellBoxes = new List<float[]>();
                _touchedWritableDbs = new List<Db>();
            }

            public ShrinkwrapModelRequest Request { get; }
            public ShrinkwrapModelResult Result { get; }
            public string CurrentZoneName { get; private set; }

            private readonly HashSet<string> _keepTypes;
            private float[] _zoneBox;
            private float[] _innerBox;
            private float[] _innerDeleteBox;
            private List<float[]> _shellBoxes;

            public bool ShouldProcessZone(DbElement zone)
            {
                if (Request.ZoneFilters == null || Request.ZoneFilters.Count == 0)
                {
                    return true;
                }

                var zonePath = BuildElementPath(zone).ToUpperInvariant();
                return Request.ZoneFilters.Any(filter => zonePath.Contains(filter));
            }

            public void EnterZone(DbElement zone)
            {
                CurrentZoneName = BuildElementPath(zone);
                if (!Result.ZoneSummaries.Contains(CurrentZoneName))
                {
                    Result.ZoneSummaries.Add(CurrentZoneName);
                }
            }

            public void ProcessZone(DbElement zone)
            {
                if (!TryGetZoneBounds(zone, out _zoneBox))
                {
                    SnapshotUnsafe(BuildElementPath(zone), "ZONE", "Zone及其子元素均无法计算包围盒");
                    return;
                }

                _innerBox = BuildInnerBox(_zoneBox, (float)Math.Max(0d, Request.Padding));
                _innerDeleteBox = BuildDeleteCoreBox(_innerBox, (float)Math.Max(0d, Request.TouchTolerance));
                _shellBoxes = BuildShellBoxes(_zoneBox, _innerDeleteBox);

                if (_innerDeleteBox == null || _shellBoxes == null || _shellBoxes.Count == 0)
                {
                    SnapshotUnsafe(BuildElementPath(zone), "ZONE", "Zone几何边界不足以构建保壳删除区域");
                    return;
                }

                if (!ProcessZoneWithExactSpatial(zone))
                {
                    Result.UsedExactSpatial = false;
                    ProcessFallbackCandidates(zone);
                }
            }

            public IList<Db> GetTouchedWritableDbs()
            {
                return _touchedWritableDbs;
            }

            private bool TryGetZoneBounds(DbElement zone, out float[] box)
            {
                box = null;
                if (!IsElementValid(zone))
                {
                    return false;
                }

                if (TryGetLimitsBox(zone, out box))
                {
                    return true;
                }

                var aggregate = new List<float[]>();
                CollectDescendantBoxes(zone, aggregate);
                if (aggregate.Count == 0)
                {
                    return false;
                }

                box = MergeBoxes(aggregate);
                return box != null;
            }

            private void CollectDescendantBoxes(DbElement parent, List<float[]> boxes)
            {
                var members = SnapshotMembers(parent);
                for (int i = 0; i < members.Count; i++)
                {
                    var child = members[i];
                    if (!IsElementValid(child))
                    {
                        continue;
                    }

                    float[] childBox;
                    if (TryGetLimitsBox(child, out childBox))
                    {
                        boxes.Add(childBox);
                    }

                    CollectDescendantBoxes(child, boxes);
                }
            }

            private bool ProcessZoneWithExactSpatial(DbElement zone)
            {
                if (_shellBoxes == null || _shellBoxes.Count == 0 || _innerDeleteBox == null)
                {
                    return false;
                }

                var spatial = Spatial.Instance;
                if (spatial == null)
                {
                    return false;
                }

                DbElement[] candidates;
                try
                {
                    candidates = spatial.ElementsInElementExact(zone, true);
                }
                catch
                {
                    return false;
                }

                if (candidates == null || candidates.Length == 0)
                {
                    Result.UsedExactSpatial = true;
                    return true;
                }

                Array.Sort(candidates, delegate (DbElement a, DbElement b)
                {
                    return GetOwnerDepth(b).CompareTo(GetOwnerDepth(a));
                });

                Result.UsedExactSpatial = true;
                foreach (var element in candidates)
                {
                    ProcessExactCandidate(element, zone);
                }

                return true;
            }

            private void ProcessExactCandidate(DbElement element, DbElement zone)
            {
                if (!IsElementValid(element))
                {
                    return;
                }

                Result.TotalVisited++;

                var typeName = GetElementTypeName(element);
                var normalizedType = string.IsNullOrEmpty(typeName) ? string.Empty : typeName.ToUpperInvariant();

                if (_keepTypes.Contains(normalizedType))
                {
                    Result.KeptCount++;
                    return;
                }

                if (OverlapsAnyShellBox(element))
                {
                    Result.ShellKeptCount++;
                    Result.KeptCount++;
                    return;
                }

                bool overlapsDeleteCore;
                if (!TryElementInBox(element, _innerDeleteBox, out overlapsDeleteCore))
                {
                    float[] box;
                    if (TryGetLimitsBox(element, out box) && IsInsideInnerBox(box, _innerDeleteBox, 0f))
                    {
                        RemoveElement(element, normalizedType, zone, "exact-inner");
                        return;
                    }

                    SnapshotUnsafe(elementPath: BuildElementPath(element), typeName: normalizedType, reason: "无法稳定计算删除核包围盒关系");
                    return;
                }

                if (overlapsDeleteCore)
                {
                    RemoveElement(element, normalizedType, zone, "exact-overlap");
                    return;
                }

                Result.KeptCount++;
            }

            private void ProcessFallbackCandidates(DbElement zone)
            {
                var candidates = new List<ShrinkwrapCandidate>();
                CollectFallbackCandidates(zone, candidates, zone);

                candidates.Sort(delegate (ShrinkwrapCandidate a, ShrinkwrapCandidate b)
                {
                    return b.Depth.CompareTo(a.Depth);
                });

                for (int i = 0; i < candidates.Count; i++)
                {
                    ProcessFallbackCandidate(candidates[i], zone);
                }
            }

            private void CollectFallbackCandidates(DbElement parent, List<ShrinkwrapCandidate> candidates, DbElement zone)
            {
                var members = SnapshotMembers(parent);
                for (int i = 0; i < members.Count; i++)
                {
                    var child = members[i];
                    if (!IsElementValid(child))
                    {
                        continue;
                    }

                    candidates.Add(new ShrinkwrapCandidate(child, GetOwnerDepth(child)));
                    CollectFallbackCandidates(child, candidates, zone);
                }
            }

            private void ProcessFallbackCandidate(ShrinkwrapCandidate candidate, DbElement zone)
            {
                var element = candidate.Element;
                if (!IsElementValid(element))
                {
                    return;
                }

                Result.TotalVisited++;

                var typeName = GetElementTypeName(element);
                var normalizedType = string.IsNullOrEmpty(typeName) ? string.Empty : typeName.ToUpperInvariant();

                if (_keepTypes.Contains(normalizedType))
                {
                    Result.KeptCount++;
                    return;
                }

                if (OverlapsAnyShellBox(element))
                {
                    Result.ShellKeptCount++;
                    Result.KeptCount++;
                    return;
                }

                float[] box;
                if (!TryGetLimitsBox(element, out box))
                {
                    SnapshotUnsafe(BuildElementPath(element), normalizedType, "无法计算包围盒");
                    return;
                }

                if (IsInsideInnerBox(box, _innerDeleteBox, 0f))
                {
                    RemoveElement(element, normalizedType, zone, "fallback-inner");
                    return;
                }

                Result.KeptCount++;
            }

            private bool OverlapsAnyShellBox(DbElement element)
            {
                if (_shellBoxes == null || _shellBoxes.Count == 0)
                {
                    return false;
                }

                foreach (var shellBox in _shellBoxes)
                {
                    bool overlaps;
                    if (TryElementInBox(element, shellBox, out overlaps) && overlaps)
                    {
                        return true;
                    }
                }

                return false;
            }

            private void RemoveElement(DbElement element, string typeName, DbElement zone, string source)
            {
                var elementPath = BuildElementPath(element);

                try
                {
                    string linkedReason;
                    if (ShouldSkipLinkedElement(element, Request.SkipLinkedElements, out linkedReason))
                    {
                        Result.KeptCount++;
                        SnapshotSkipped(elementPath, typeName, linkedReason);
                        return;
                    }

                    string unsafeReason;
                    Db elementDb;
                    if (!IsSafeToDelete(element, zone, out elementDb, out unsafeReason))
                    {
                        SnapshotUnsafe(elementPath, typeName, unsafeReason);
                        return;
                    }

                    if (Request.DryRun)
                    {
                        SnapshotRemoval(elementPath, typeName, true);
                        return;
                    }

                    element.Delete();
                    SnapshotRemoval(elementPath, typeName, false);
                    TrackTouchedDb(elementDb);
                }
                catch (Exception ex)
                {
                    Result.Errors.Add("删除元素 " + elementPath + " 失败: " + ex.Message);
                }
            }

            private void SnapshotRemoval(string elementPath, string typeName, bool dryRun)
            {
                Result.RemovedCount++;

                if (Result.RemovedElements.Count < MaxRemovedSnapshots)
                {
                    Result.RemovedElements.Add((dryRun ? "[DRYRUN-DEL] " : "[DEL] ") + elementPath + " (" + typeName + ")");
                }
            }

            private void SnapshotSkipped(string elementPath, string typeName, string reason)
            {
                Result.SkippedLinkedCount++;

                if (Result.SkippedLinkedElements.Count < MaxSkippedSnapshots)
                {
                    var suffix = string.IsNullOrEmpty(reason) ? string.Empty : (" [" + reason + "]");
                    Result.SkippedLinkedElements.Add("[SKIP-LINKED] " + elementPath + " (" + typeName + ")" + suffix);
                }
            }

            private void SnapshotUnsafe(string elementPath, string typeName, string reason)
            {
                Result.KeptCount++;
                Result.SkippedUnsafeCount++;

                if (Result.SkippedUnsafeElements.Count < MaxSkippedSnapshots)
                {
                    var suffix = string.IsNullOrEmpty(reason) ? string.Empty : (" [" + reason + "]");
                    Result.SkippedUnsafeElements.Add("[SKIP-UNSAFE] " + elementPath + " (" + typeName + ")" + suffix);
                }
            }

            private bool IsSafeToDelete(DbElement element, DbElement zone, out Db elementDb, out string reason)
            {
                elementDb = null;
                reason = null;

                if (!IsElementValid(element))
                {
                    reason = "元素无效";
                    return false;
                }

                if (!IsElementValid(zone))
                {
                    reason = "Zone无效";
                    return false;
                }

                var owner = element.Owner;
                if (!IsElementValid(owner))
                {
                    reason = "Owner无效";
                    return false;
                }

                if (!IsElementUnderOwner(element, zone))
                {
                    reason = "元素已不在目标Zone下";
                    return false;
                }

                if (!TryGetElementDb(element, out elementDb) || elementDb == null)
                {
                    reason = "无法确认元素所属DB";
                    return false;
                }

                if (!IsDesignDb(elementDb))
                {
                    reason = "元素所属DB不是Design DB";
                    return false;
                }

                if (IsDbReadOnly(elementDb))
                {
                    reason = "元素所属DB为只读";
                    return false;
                }

                return true;
            }

            private void TrackTouchedDb(Db db)
            {
                if (db == null || IsDbReadOnly(db))
                {
                    return;
                }

                if (!ContainsDb(_touchedWritableDbs, db))
                {
                    _touchedWritableDbs.Add(db);
                }
            }

            private static List<DbElement> SnapshotMembers(DbElement parent)
            {
                var snapshot = new List<DbElement>();
                if (!IsElementValid(parent))
                {
                    return snapshot;
                }

                DbElement[] members = null;
                try
                {
                    members = parent.Members();
                }
                catch
                {
                    return snapshot;
                }

                if (members == null)
                {
                    return snapshot;
                }

                for (int i = 0; i < members.Length; i++)
                {
                    snapshot.Add(members[i]);
                }

                return snapshot;
            }

            private static int GetOwnerDepth(DbElement element)
            {
                var current = element;
                int depth = 0;
                int guard = 0;

                while (IsElementValid(current) && guard < 512)
                {
                    depth++;
                    current = current.Owner;
                    guard++;
                }

                return depth;
            }

            private static bool TryElementInBox(DbElement element, float[] box, out bool overlaps)
            {
                overlaps = false;
                if (!IsElementValid(element) || box == null || box.Length < 6)
                {
                    return false;
                }

                try
                {
                    float[] elementBox;
                    if (!TryGetLimitsBox(element, out elementBox))
                    {
                        return false;
                    }

                    overlaps = BoxesOverlap(elementBox, box);
                    return true;
                }
                catch
                {
                    return false;
                }
            }

            private static bool TryGetLimitsBox(DbElement element, out float[] box)
            {
                box = null;
                if (!IsElementValid(element))
                {
                    return false;
                }

                try
                {
                    var spatial = Spatial.Instance;
                    if (spatial == null)
                    {
                        return false;
                    }

                    var spatialType = spatial.GetType();

                    var arrayMethod = spatialType.GetMethod("LimitsBox", new[] { typeof(DbElement), typeof(float[]) });
                    if (arrayMethod != null)
                    {
                        var args = new object[] { element, new float[6] };
                        var okObj = arrayMethod.Invoke(spatial, args);
                        if (okObj is bool && (bool)okObj)
                        {
                            if (TryNormalizeBox(args[1] as float[], out box))
                            {
                                return true;
                            }
                        }
                    }

                    var methods = spatialType.GetMethods().Where(m => m.Name == "LimitsBox").ToArray();
                    foreach (var method in methods)
                    {
                        var parameters = method.GetParameters();
                        if (parameters.Length != 2 || parameters[0].ParameterType != typeof(DbElement) || !parameters[1].ParameterType.IsByRef)
                        {
                            continue;
                        }

                        object boxValue;
                        try
                        {
                            boxValue = Activator.CreateInstance(parameters[1].ParameterType.GetElementType());
                        }
                        catch
                        {
                            continue;
                        }

                        var args = new object[] { element, boxValue };
                        var okObj = method.Invoke(spatial, args);
                        if (!(okObj is bool) || !(bool)okObj)
                        {
                            continue;
                        }

                        var converted = ConvertLimitsBoxObject(args[1]);
                        if (TryNormalizeBox(converted, out box))
                        {
                            return true;
                        }
                    }
                }
                catch
                {
                    // ignore
                }

                return false;
            }

            private static float[] ConvertLimitsBoxObject(object limits)
            {
                if (limits == null)
                {
                    return null;
                }

                var type = limits.GetType();

                try
                {
                    float xmin = ReadFloat(limits, type, new[] { "XMIN", "XMin", "MinX", "Xmin" });
                    float ymin = ReadFloat(limits, type, new[] { "YMIN", "YMin", "MinY", "Ymin" });
                    float zmin = ReadFloat(limits, type, new[] { "ZMIN", "ZMin", "MinZ", "Zmin" });
                    float xmax = ReadFloat(limits, type, new[] { "XMAX", "XMax", "MaxX", "Xmax" });
                    float ymax = ReadFloat(limits, type, new[] { "YMAX", "YMax", "MaxY", "Ymax" });
                    float zmax = ReadFloat(limits, type, new[] { "ZMAX", "ZMax", "MaxZ", "Zmax" });
                    return new[] { xmin, ymin, zmin, xmax, ymax, zmax };
                }
                catch
                {
                    return null;
                }
            }

            private static float ReadFloat(object boxed, Type type, string[] names)
            {
                foreach (var name in names)
                {
                    var prop = type.GetProperty(name);
                    if (prop != null)
                    {
                        var value = prop.GetValue(boxed, null);
                        if (value != null)
                        {
                            return Convert.ToSingle(value);
                        }
                    }

                    var field = type.GetField(name);
                    if (field != null)
                    {
                        var value = field.GetValue(boxed);
                        if (value != null)
                        {
                            return Convert.ToSingle(value);
                        }
                    }
                }

                throw new InvalidOperationException("LimitsBox缺少必要字段/属性");
            }

            private static bool TryNormalizeBox(float[] source, out float[] normalized)
            {
                normalized = null;
                if (source == null || source.Length < 6)
                {
                    return false;
                }

                float xmin = Math.Min(source[0], source[3]);
                float ymin = Math.Min(source[1], source[4]);
                float zmin = Math.Min(source[2], source[5]);
                float xmax = Math.Max(source[0], source[3]);
                float ymax = Math.Max(source[1], source[4]);
                float zmax = Math.Max(source[2], source[5]);

                if ((xmax - xmin) < MinBoxEdge || (ymax - ymin) < MinBoxEdge || (zmax - zmin) < MinBoxEdge)
                {
                    return false;
                }

                normalized = new[] { xmin, ymin, zmin, xmax, ymax, zmax };
                return true;
            }

            private static float[] BuildInnerBox(float[] outerBox, float padding)
            {
                if (outerBox == null || outerBox.Length < 6)
                {
                    return null;
                }

                var inner = new float[6];
                inner[0] = outerBox[0] + padding;
                inner[1] = outerBox[1] + padding;
                inner[2] = outerBox[2] + padding;
                inner[3] = outerBox[3] - padding;
                inner[4] = outerBox[4] - padding;
                inner[5] = outerBox[5] - padding;

                if (inner[3] < inner[0])
                {
                    inner[0] = outerBox[0];
                    inner[3] = outerBox[3];
                }

                if (inner[4] < inner[1])
                {
                    inner[1] = outerBox[1];
                    inner[4] = outerBox[4];
                }

                if (inner[5] < inner[2])
                {
                    inner[2] = outerBox[2];
                    inner[5] = outerBox[5];
                }

                return inner;
            }

            private static float[] BuildDeleteCoreBox(float[] innerBox, float tolerance)
            {
                if (innerBox == null || innerBox.Length < 6)
                {
                    return null;
                }

                var core = new float[6];
                var offset = Math.Max(0f, tolerance);
                core[0] = innerBox[0] + offset;
                core[1] = innerBox[1] + offset;
                core[2] = innerBox[2] + offset;
                core[3] = innerBox[3] - offset;
                core[4] = innerBox[4] - offset;
                core[5] = innerBox[5] - offset;

                float[] normalized;
                return TryNormalizeBox(core, out normalized) ? normalized : null;
            }

            private static List<float[]> BuildShellBoxes(float[] outerBox, float[] innerDeleteBox)
            {
                var boxes = new List<float[]>();
                if (outerBox == null || innerDeleteBox == null)
                {
                    return boxes;
                }

                AddShellBox(boxes, outerBox[0], outerBox[1], outerBox[2], innerDeleteBox[0], outerBox[4], outerBox[5]); // Left
                AddShellBox(boxes, innerDeleteBox[3], outerBox[1], outerBox[2], outerBox[3], outerBox[4], outerBox[5]); // Right
                AddShellBox(boxes, innerDeleteBox[0], outerBox[1], outerBox[2], innerDeleteBox[3], innerDeleteBox[1], outerBox[5]); // Front
                AddShellBox(boxes, innerDeleteBox[0], innerDeleteBox[4], outerBox[2], innerDeleteBox[3], outerBox[4], outerBox[5]); // Back
                AddShellBox(boxes, innerDeleteBox[0], innerDeleteBox[1], outerBox[2], innerDeleteBox[3], innerDeleteBox[4], innerDeleteBox[2]); // Bottom
                AddShellBox(boxes, innerDeleteBox[0], innerDeleteBox[1], innerDeleteBox[5], innerDeleteBox[3], innerDeleteBox[4], outerBox[5]); // Top

                return boxes;
            }

            private static void AddShellBox(List<float[]> boxes, float xmin, float ymin, float zmin, float xmax, float ymax, float zmax)
            {
                var candidate = new[] { xmin, ymin, zmin, xmax, ymax, zmax };
                float[] normalized;
                if (TryNormalizeBox(candidate, out normalized))
                {
                    boxes.Add(normalized);
                }
            }

            private static bool IsInsideInnerBox(float[] box, float[] innerBox, float tolerance)
            {
                if (box == null || innerBox == null || box.Length < 6 || innerBox.Length < 6)
                {
                    return false;
                }

                return (box[0] > innerBox[0] + tolerance) &&
                       (box[1] > innerBox[1] + tolerance) &&
                       (box[2] > innerBox[2] + tolerance) &&
                       (box[3] < innerBox[3] - tolerance) &&
                       (box[4] < innerBox[4] - tolerance) &&
                       (box[5] < innerBox[5] - tolerance);
            }

            private static bool BoxesOverlap(float[] a, float[] b)
            {
                if (a == null || b == null || a.Length < 6 || b.Length < 6)
                {
                    return false;
                }

                return (a[0] <= b[3]) && (a[3] >= b[0]) &&
                       (a[1] <= b[4]) && (a[4] >= b[1]) &&
                       (a[2] <= b[5]) && (a[5] >= b[2]);
            }

            private static float[] MergeBoxes(IList<float[]> boxes)
            {
                if (boxes == null || boxes.Count == 0)
                {
                    return null;
                }

                float xmin = float.MaxValue;
                float ymin = float.MaxValue;
                float zmin = float.MaxValue;
                float xmax = float.MinValue;
                float ymax = float.MinValue;
                float zmax = float.MinValue;
                bool found = false;

                for (int i = 0; i < boxes.Count; i++)
                {
                    var box = boxes[i];
                    if (box == null || box.Length < 6)
                    {
                        continue;
                    }

                    xmin = Math.Min(xmin, box[0]);
                    ymin = Math.Min(ymin, box[1]);
                    zmin = Math.Min(zmin, box[2]);
                    xmax = Math.Max(xmax, box[3]);
                    ymax = Math.Max(ymax, box[4]);
                    zmax = Math.Max(zmax, box[5]);
                    found = true;
                }

                if (!found)
                {
                    return null;
                }

                float[] merged;
                return TryNormalizeBox(new[] { xmin, ymin, zmin, xmax, ymax, zmax }, out merged) ? merged : null;
            }

            private class ShrinkwrapCandidate
            {
                public ShrinkwrapCandidate(DbElement element, int depth)
                {
                    Element = element;
                    Depth = depth;
                }

                public DbElement Element { get; private set; }
                public int Depth { get; private set; }
            }
        }
    }
}