using System;
using System.Collections.Generic;
using System.Data;
using System.Diagnostics;
using System.Drawing;
using System.IO;
using System.Windows.Forms;
using Microsoft.Win32;
using Smart.CustomComponents;

namespace 成套报价软件
{
    /// <summary>主窗口 拆分文件:由 主窗口.cs 按模块拆出,同一 partial class。</summary>
    public partial class MainForm
    {
        // ============================================================
        //  项目导入/导出
        //  · 导出:把选中项目的独立库(项目<编号>.db)和元数据(项目列表那一行)
        //         打包成一个 .zip 文件,带元数据 meta.json
        //  · 导入:解压 .zip → 项目编号冲突时自动改名 → db 放到 sjk\bjb\ →
        //         元数据 INSERT 到项目列表 → 刷新项目表显示
        // ============================================================

        // <summary>导出项目:读项目表 → 弹列表让用户选 → 打包导出。</summary>
        private void button7_Click(object sender, EventArgs e)
        {
            string pid = "";
            string dbPath = "";
            string dstDb = "";
            string zipPath = "";
            try
            {
                Log("[项目导出] ===== 开始导出 =====");

                // ① 先从项目表读取所有项目
                Log("[项目导出] 步骤1: 读项目表");
                var projects = ReadAllProjectsFromDatabase();
                if (projects == null || projects.Count == 0)
                {
                    MessageBox.Show(this, "项目列表为空,无项目可导出。",
                        "导出项目", MessageBoxButtons.OK, MessageBoxIcon.Information);
                    return;
                }
                Log("[项目导出] 步骤1完成: 共 " + projects.Count + " 个项目");

                // ② 弹出列表让用户选择要导出的项目(支持多选)
                Log("[项目导出] 步骤2: 选择项目(多选)");
                var selectedPids = new System.Collections.Generic.List<string>();
                if (projects.Count == 1)
                {
                    var first = projects[0];
                    string singlePid = first.ContainsKey("项目编号") ? (first["项目编号"] ?? "").ToString() : "";
                    if (!string.IsNullOrWhiteSpace(singlePid)) selectedPids.Add(singlePid);
                }
                else
                {
                    selectedPids = PickProjectDialogMulti(projects);
                    if (selectedPids == null || selectedPids.Count == 0)
                    {
                        Log("[项目导出] 用户取消选择");
                        return;
                    }
                }

                if (selectedPids == null || selectedPids.Count == 0)
                {
                    MessageBox.Show(this, "未能确定要导出的项目编号。",
                        "导出项目", MessageBoxButtons.OK, MessageBoxIcon.Warning);
                    return;
                }
                Log("[项目导出] 步骤2完成: 选中 " + selectedPids.Count + " 个项目");

                // 先把当前项目所有未保存的修改写库
                Log("[项目导出] 步骤3: SaveAllToDatabase");
                SaveAllToDatabase();
                Log("[项目导出] 步骤3完成");

                // ★ 选择保存位置:单个项目弹文件对话框,多个项目弹文件夹对话框
                string singleZipPath = "";

                if (selectedPids.Count == 1)
                {
                    // ===== 单项目导出:弹保存文件对话框(保持原有行为)=====
                    pid = selectedPids[0];
                    dbPath = GetQuoteDbPath(pid);
                    if (!System.IO.File.Exists(dbPath))
                    {
                        MessageBox.Show(this, "项目数据库文件不存在:\n" + dbPath,
                            "导出项目", MessageBoxButtons.OK, MessageBoxIcon.Warning);
                        return;
                    }

                    var meta = ReadProjectMetaData(pid);
                    if (meta == null)
                    {
                        MessageBox.Show(this, "项目元数据读取失败,项目编号:" + pid,
                            "导出项目", MessageBoxButtons.OK, MessageBoxIcon.Warning);
                        return;
                    }

                    string projName = meta.ContainsKey("项目名称") ? (meta["项目名称"] ?? "").ToString() : "";
                    string safeName = MakeSafeFileName(projName);
                    if (string.IsNullOrWhiteSpace(safeName)) safeName = MakeSafeFileName(pid);
                    string defaultFileName = safeName + ".zip";

                    string initialDir = "";
                    try
                    {
                        string desktop = Environment.GetFolderPath(Environment.SpecialFolder.Desktop);
                        if (!string.IsNullOrEmpty(desktop) && System.IO.Directory.Exists(desktop))
                            initialDir = desktop;
                    }
                    catch { }
                    if (string.IsNullOrEmpty(initialDir))
                    {
                        try
                        {
                            string docs = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
                            if (!string.IsNullOrEmpty(docs) && System.IO.Directory.Exists(docs))
                                initialDir = docs;
                        }
                        catch { }
                    }

                    using (var sfd = new SaveFileDialog
                    {
                        Title = "导出项目",
                        Filter = "项目包 (*.zip)|*.zip",
                        FileName = defaultFileName,
                        RestoreDirectory = true,
                    })
                    {
                        if (!string.IsNullOrEmpty(initialDir))
                            sfd.InitialDirectory = initialDir;

                        if (sfd.ShowDialog(this) != DialogResult.OK)
                        {
                            Log("[项目导出] 用户取消保存");
                            return;
                        }
                        singleZipPath = sfd.FileName;
                    }

                    // 导出单个
                    var pidsToExport = new System.Collections.Generic.List<string>();
                    pidsToExport.Add(pid);
                    int okCount = ExportProjectsToZip(pidsToExport, null, singleZipPath);
                    if (okCount > 0)
                    {
                        MessageBox.Show(this,
                            "导出成功!\n\n文件:" + singleZipPath,
                            "导出项目", MessageBoxButtons.OK, MessageBoxIcon.Information);
                    }
                }
                else
                {
                    // ===== 多项目导出:打成一个 zip 包,里面每个项目一个子文件夹 =====
                    string initialDir = "";
                    try
                    {
                        string desktop = Environment.GetFolderPath(Environment.SpecialFolder.Desktop);
                        if (!string.IsNullOrEmpty(desktop) && System.IO.Directory.Exists(desktop))
                            initialDir = desktop;
                    }
                    catch { }

                    string multiZipPath = "";
                    using (var sfd = new SaveFileDialog
                    {
                        Title = "导出 " + selectedPids.Count + " 个项目到一个压缩包",
                        Filter = "项目包 (*.zip)|*.zip",
                        FileName = selectedPids.Count + "个项目_" + DateTime.Now.ToString("yyyyMMdd") + ".zip",
                        RestoreDirectory = true,
                    })
                    {
                        if (!string.IsNullOrEmpty(initialDir))
                            sfd.InitialDirectory = initialDir;

                        if (sfd.ShowDialog(this) != DialogResult.OK)
                        {
                            Log("[项目导出] 用户取消保存");
                            return;
                        }
                        multiZipPath = sfd.FileName;
                    }

                    // 批量导出到一个 zip(每个项目一个子文件夹)
                    int okCount = ExportProjectsToSingleZip(selectedPids, multiZipPath);
                    MessageBox.Show(this,
                        "批量导出完成!\n\n成功导出 " + okCount + " / " + selectedPids.Count + " 个项目\n压缩包:" + multiZipPath,
                        "导出项目", MessageBoxButtons.OK, MessageBoxIcon.Information);
                }
                Log("[项目导出] ===== 导出成功 =====");
            }
            catch (Exception ex)
            {
                Log("[项目导出异常] 失败步骤位置: pid=[" + pid + "] dbPath=[" + dbPath +
                    "] dstDb=[" + dstDb + "] zipPath=[" + zipPath + "]");
                Log("[项目导出异常] " + ex.GetType().Name + ": " + ex.Message);
                Log("[项目导出异常] 堆栈:\n" + ex.StackTrace);
                MessageBox.Show(this,
                    "导出失败:\n" + ex.Message +
                    "\n\n异常类型: " + ex.GetType().Name +
                    "\n\n=== 详细堆栈 ===\n" + ex.StackTrace,
                    "导出项目", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }

        /// <summary>
        /// 把多个项目打到同一个 .zip 包里,每个项目一个子文件夹(以项目名称命名)。
        /// 返回成功导出的数量。
        /// </summary>
        private int ExportProjectsToSingleZip(System.Collections.Generic.List<string> pids, string zipPath)
        {
            int okCount = 0;
            // 临时根目录
            string tempRoot = System.IO.Path.Combine(System.IO.Path.GetTempPath(),
                "成套报价_批量导出_" + System.Guid.NewGuid().ToString("N"));
            System.IO.Directory.CreateDirectory(tempRoot);

            // 记录子文件夹名,用于去重(项目名可能重复)
            var usedNames = new System.Collections.Generic.HashSet<string>(System.StringComparer.Ordinal);

            try
            {
                foreach (string currentPid in pids)
                {
                    try
                    {
                        string currentDbPath = GetQuoteDbPath(currentPid);
                        if (!System.IO.File.Exists(currentDbPath))
                        {
                            Log("[项目导出] 跳过(数据库不存在): " + currentPid);
                            continue;
                        }

                        var meta = ReadProjectMetaData(currentPid);
                        if (meta == null)
                        {
                            Log("[项目导出] 跳过(元数据读取失败): " + currentPid);
                            continue;
                        }

                        // 子文件夹名 = 项目名称(去重)
                        string projName = meta.ContainsKey("项目名称") ? (meta["项目名称"] ?? "").ToString() : "";
                        string folderName = MakeSafeFileName(projName);
                        if (string.IsNullOrWhiteSpace(folderName)) folderName = MakeSafeFileName(currentPid);
                        // 去重:同名项目加编号
                        if (usedNames.Contains(folderName))
                        {
                            string baseFolder = folderName;
                            int dup = 1;
                            while (usedNames.Contains(folderName))
                            {
                                folderName = baseFolder + "(" + dup + ")";
                                dup++;
                            }
                        }
                        usedNames.Add(folderName);

                        // 创建子文件夹
                        string subDir = System.IO.Path.Combine(tempRoot, folderName);
                        System.IO.Directory.CreateDirectory(subDir);

                        // 复制 db
                        string dstDbFile = System.IO.Path.Combine(subDir, "项目" + MakeSafeFileName(currentPid) + ".db");
                        BackupSQLiteDb(currentDbPath, dstDbFile);

                        // 写 meta.json
                        var sb = new System.Text.StringBuilder();
                        sb.Append("{\n  \"项目编号\": \"");
                        sb.Append(EscapeJsonString(currentPid));
                        sb.Append("\",\n  \"字段\": {");
                        bool firstKv = true;
                        foreach (var kv in meta)
                        {
                            if (firstKv) firstKv = false; else sb.Append(",");
                            sb.Append("\n    \"");
                            sb.Append(EscapeJsonString(kv.Key));
                            sb.Append("\": \"");
                            sb.Append(EscapeJsonString((kv.Value ?? "").ToString()));
                            sb.Append("\"");
                        }
                        sb.Append("\n  }\n}");

                        string metaPath = System.IO.Path.Combine(subDir, "meta.json");
                        System.IO.File.WriteAllText(metaPath, sb.ToString(), new System.Text.UTF8Encoding(false));

                        okCount++;
                        Log("[项目导出] 批量: " + currentPid + " → 子文件夹[" + folderName + "]");
                    }
                    catch (Exception exProj)
                    {
                        Log("[项目导出] 单个项目导出失败 [" + currentPid + "]: " + exProj.Message);
                    }
                }

                // 全部完成后打成一个 zip
                if (okCount > 0)
                {
                    if (System.IO.File.Exists(zipPath))
                        System.IO.File.Delete(zipPath);
                    System.IO.Compression.ZipFile.CreateFromDirectory(tempRoot, zipPath);
                    Log("[项目导出] 批量打包完成: " + okCount + " 个项目 → " + zipPath);
                }
            }
            finally
            {
                try { System.IO.Directory.Delete(tempRoot, true); } catch { }
            }
            return okCount;
        }

        /// <summary>
        /// 把多个项目逐个导出为独立的 .zip 文件。
        /// 导出到 exportDir 目录(多项目),或 singleZipPath(单项目)。
        /// 返回成功导出的数量。
        /// </summary>
        // ---- 项目云窗体(项目云.cs)用的转发包装:原方法 private,包装成 public 供跨类调用 ----
        public System.Collections.Generic.List<System.Collections.Generic.Dictionary<string, object>> ReadAllProjectsFromDatabaseForCloud()
        { return ReadAllProjectsFromDatabase(); }
        public string GetQuoteDbPathForCloud(string pid) { return GetQuoteDbPath(pid); }
        public System.Collections.Generic.Dictionary<string, object> ReadProjectMetaDataForCloud(string pid)
        { return ReadProjectMetaData(pid); }
        public string MakeSafeFileNameForCloud(string s) { return MakeSafeFileName(s); }
        public string EscapeJsonStringForCloud(string s) { return EscapeJsonString(s); }
        public void BackupSQLiteDbForCloud(string src, string dst) { BackupSQLiteDb(src, dst); }
        public string ImportProjectFromZipForCloud(string zipPath) { return ImportProjectFromZip(zipPath); }

        private int ExportProjectsToZip(System.Collections.Generic.List<string> pids,
            string exportDir, string singleZipPath)
        {            int okCount = 0;
            foreach (string currentPid in pids)
            {
                try
                {
                    string currentDbPath = GetQuoteDbPath(currentPid);
                    if (!System.IO.File.Exists(currentDbPath))
                    {
                        Log("[项目导出] 跳过(数据库不存在): " + currentPid);
                        continue;
                    }

                    var meta = ReadProjectMetaData(currentPid);
                    if (meta == null)
                    {
                        Log("[项目导出] 跳过(元数据读取失败): " + currentPid);
                        continue;
                    }

                    string projName = meta.ContainsKey("项目名称") ? (meta["项目名称"] ?? "").ToString() : "";
                    string safeName = MakeSafeFileName(projName);
                    if (string.IsNullOrWhiteSpace(safeName)) safeName = MakeSafeFileName(currentPid);

                    // 确定 zip 路径
                    string currentZipPath;
                    if (!string.IsNullOrEmpty(singleZipPath))
                        currentZipPath = singleZipPath;
                    else
                        currentZipPath = System.IO.Path.Combine(exportDir, safeName + ".zip");

                    // 临时目录打包
                    string tempDir = System.IO.Path.Combine(System.IO.Path.GetTempPath(),
                        "成套报价_导出_" + System.Guid.NewGuid().ToString("N"));
                    System.IO.Directory.CreateDirectory(tempDir);

                    try
                    {
                        // 复制 db
                        string dstDbFile = System.IO.Path.Combine(tempDir, "项目" + MakeSafeFileName(currentPid) + ".db");
                        BackupSQLiteDb(currentDbPath, dstDbFile);

                        // 写 meta.json
                        var sb = new System.Text.StringBuilder();
                        sb.Append("{\n  \"项目编号\": \"");
                        sb.Append(EscapeJsonString(currentPid));
                        sb.Append("\",\n  \"字段\": {");
                        bool firstKv = true;
                        foreach (var kv in meta)
                        {
                            if (firstKv) firstKv = false; else sb.Append(",");
                            sb.Append("\n    \"");
                            sb.Append(EscapeJsonString(kv.Key));
                            sb.Append("\": \"");
                            sb.Append(EscapeJsonString((kv.Value ?? "").ToString()));
                            sb.Append("\"");
                        }
                        sb.Append("\n  }\n}");

                        string metaPath = System.IO.Path.Combine(tempDir, "meta.json");
                        System.IO.File.WriteAllText(metaPath, sb.ToString(), new System.Text.UTF8Encoding(false));

                        // 打包 zip
                        if (System.IO.File.Exists(currentZipPath))
                            System.IO.File.Delete(currentZipPath);
                        System.IO.Compression.ZipFile.CreateFromDirectory(tempDir, currentZipPath);

                        okCount++;
                        Log("[项目导出] 成功: " + currentPid + " → " + currentZipPath);
                    }
                    finally
                    {
                        try { System.IO.Directory.Delete(tempDir, true); } catch { }
                    }
                }
                catch (Exception exProj)
                {
                    Log("[项目导出] 单个项目导出失败 [" + currentPid + "]: " + exProj.Message);
                }
            }
            return okCount;
        }

        /// <summary>
        /// 复制 SQLite 数据库文件到目标路径,解决"没有权限/被占用"问题。
        /// 主路径:用 SQL ATTACH + CREATE TABLE AS SELECT 在 SQL 层复制,完全绕开文件锁
        /// 兜底:File.Copy + ClearAllPools(以防 SQL 复制失败)
        /// </summary>
        private void BackupSQLiteDb(string srcDbPath, string dstDbPath)
        {
            // 清掉旧的目标文件(失败也无所谓,SQL CREATE 会覆盖)
            TryDeleteFile(dstDbPath);

            // ① 主路径:SQL 层复制(完全绕开文件锁)
            Exception sqlErr = null;
            try
            {
                // 用独立的 Pooling=False 连接,不参与主程序的连接池。
                // 注意:不能加 ReadOnly=True — 只读连接上 ATTACH 新建目标库会被拒
                // (unable to open database),导致总是掉进 File.Copy 兜底。
                using (var srcConn = new System.Data.SQLite.SQLiteConnection(
                    "Data Source=" + srcDbPath + ";Version=3;Pooling=False;"))
                {
                    srcConn.Open();

                    // 把目标库 ATTACH 上来,别名 dst
                    using (var att = new System.Data.SQLite.SQLiteCommand(
                        "ATTACH DATABASE @path AS dst;", srcConn))
                    {
                        att.Parameters.AddWithValue("@path", dstDbPath);
                        att.ExecuteNonQuery();
                    }

                    try
                    {
                        // 读源库所有表(排除 sqlite_ 系统表)
                        var tableNames = new System.Collections.Generic.List<string>();
                        using (var sel = new System.Data.SQLite.SQLiteCommand(
                            "SELECT name FROM sqlite_master WHERE type='table' AND name NOT LIKE 'sqlite_%';", srcConn))
                        using (var rd = sel.ExecuteReader())
                        {
                            while (rd.Read())
                            {
                                string nm = rd.GetString(0);
                                if (!string.IsNullOrEmpty(nm))
                                    tableNames.Add(nm);
                            }
                        }

                        // 逐表复制(结构 + 数据 + 自增主键)
                        foreach (string tbl in tableNames)
                        {
                            string safe = tbl.Replace("\"", "\"\"");
                            string main = "main.\"" + safe + "\"";
                            string dst = "dst.\"" + safe + "\"";

                            // 1) 拿源表的 CREATE 语句,改个名建到 dst 下
                            string createSql = null;
                            using (var selSql = new System.Data.SQLite.SQLiteCommand(
                                "SELECT sql FROM sqlite_master WHERE type='table' AND name=@n;", srcConn))
                            {
                                selSql.Parameters.AddWithValue("@n", tbl);
                                object o = selSql.ExecuteScalar();
                                createSql = (o == null || o == DBNull.Value) ? null : o.ToString();
                            }

                            if (!string.IsNullOrEmpty(createSql))
                            {
                                // 把 CREATE TABLE "原表名" 替换成 CREATE TABLE dst."原表名"
                                // 简单处理:在 CREATE TABLE 后插入 dst.
                                string dstCreateSql = createSql.Replace(
                                    "CREATE TABLE \"" + safe + "\"",
                                    "CREATE TABLE dst.\"" + safe + "\"");
                                // 兜底替换:可能 sqlite_master 存的是不带引号的形式
                                if (dstCreateSql == createSql)
                                {
                                    dstCreateSql = createSql.Replace(
                                        "CREATE TABLE " + tbl,
                                        "CREATE TABLE dst.\"" + safe + "\"");
                                }
                                using (var ct = new System.Data.SQLite.SQLiteCommand(dstCreateSql, srcConn))
                                    ct.ExecuteNonQuery();

                                // 2) INSERT 数据
                                using (var ins = new System.Data.SQLite.SQLiteCommand(
                                    "INSERT INTO " + dst + " SELECT * FROM " + main + ";", srcConn))
                                    ins.ExecuteNonQuery();
                            }
                            else
                            {
                                // 兜底:CREATE AS SELECT(自增主键不会保留,但本场景没主键也无所谓)
                                using (var cp = new System.Data.SQLite.SQLiteCommand(
                                    "CREATE TABLE " + dst + " AS SELECT * FROM " + main + ";", srcConn))
                                    cp.ExecuteNonQuery();
                            }
                        }
                    }
                    finally
                    {
                        try
                        {
                            using (var det = new System.Data.SQLite.SQLiteCommand("DETACH DATABASE dst;", srcConn))
                                det.ExecuteNonQuery();
                        }
                        catch { }
                    }
                }
                return;  // 成功
            }
            catch (Exception ex)
            {
                sqlErr = ex;
                Log("[项目复制] SQL 复制失败,改用 File.Copy: " + ex.Message);
                TryDeleteFile(dstDbPath);  // 清理半成品
            }

            // ② 兜底:File.Copy + ClearAllPools 重试 3 次
            for (int attempt = 1; attempt <= 3; attempt++)
            {
                try
                {
                    System.Data.SQLite.SQLiteConnection.ClearAllPools();
                    GC.Collect();
                    GC.WaitForPendingFinalizers();
                    System.Threading.Thread.Sleep(50 * attempt);
                    System.IO.File.Copy(srcDbPath, dstDbPath, true);
                    return;
                }
                catch (Exception ex)
                {
                    Log("[项目复制] File.Copy 第 " + attempt + " 次失败: " + ex.Message);
                }
            }

            throw new Exception("无法复制数据库文件。\n" +
                "SQL 复制失败: " + (sqlErr == null ? "(未知)" : sqlErr.Message) + "\n" +
                "File.Copy 也失败(权限/占用),请关闭其他打开此项目的程序后重试。");
        }

        /// <summary>尝试删除文件,删不掉就改名,实在不行就忽略。</summary>
        private static void TryDeleteFile(string path)
        {
            if (!System.IO.File.Exists(path)) return;
            try { System.IO.File.Delete(path); return; } catch { }
            try
            {
                string tmp = path + ".old_" + Guid.NewGuid().ToString("N").Substring(0, 6);
                System.IO.File.Move(path, tmp);
            }
            catch { }
        }

        /// <summary>从项目表读取所有项目(每个项目是一个字段字典)。</summary>
        private System.Collections.Generic.List<System.Collections.Generic.Dictionary<string, object>> ReadAllProjectsFromDatabase()
        {
            var list = new System.Collections.Generic.List<System.Collections.Generic.Dictionary<string, object>>();
            try
            {
                string dbPath = GetDbFullPath(ProjectsDbPath);
                if (!System.IO.File.Exists(dbPath)) return list;

                using (var conn = new System.Data.SQLite.SQLiteConnection(GetConnString(dbPath)))
                {
                    conn.Open();
                    using (var cmd = new System.Data.SQLite.SQLiteCommand(
                        "SELECT * FROM " + ProjectsTableName + " ORDER BY rowid;", conn))
                    using (var rd = cmd.ExecuteReader())
                    {
                        while (rd.Read())
                        {
                            var dict = new System.Collections.Generic.Dictionary<string, object>(StringComparer.Ordinal);
                            for (int i = 0; i < rd.FieldCount; i++)
                            {
                                string col = rd.GetName(i);
                                object v = rd.GetValue(i);
                                if (v == null || v == DBNull.Value) v = "";
                                dict[col] = v;
                            }
                            list.Add(dict);
                        }
                    }
                }
            }
            catch (Exception ex)
            {
                Log("[项目导出] 读项目表失败: " + ex.Message);
            }
            return list;
        }

        /// <summary>
        /// 弹出一个简单对话框,让用户从项目列表中选一个项目。
        /// 返回选中的"项目编号",用户取消返回空字符串。
        /// </summary>
        /// <summary>
        /// 弹出项目选择对话框(支持多选),返回选中的项目编号列表。
        /// </summary>
        private System.Collections.Generic.List<string> PickProjectDialogMulti(System.Collections.Generic.List<System.Collections.Generic.Dictionary<string, object>> projects)
        {
            var result = new System.Collections.Generic.List<string>();
            try
            {
                using (var dlg = new System.Windows.Forms.Form
                {
                    Text = "选择要导出的项目(可多选)",
                    StartPosition = FormStartPosition.CenterParent,
                    FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedDialog,
                    MaximizeBox = false,
                    MinimizeBox = false,
                    ClientSize = new System.Drawing.Size(520, 380),
                })
                {
                    var lbl = new System.Windows.Forms.Label
                    {
                        Text = "请选择要导出的项目(Ctrl/Shift 可多选):",
                        Location = new System.Drawing.Point(12, 12),
                        Size = new System.Drawing.Size(496, 23),
                        TextAlign = System.Drawing.ContentAlignment.MiddleLeft,
                    };
                    dlg.Controls.Add(lbl);

                    var lv = new System.Windows.Forms.ListView
                    {
                        Location = new System.Drawing.Point(12, 40),
                        Size = new System.Drawing.Size(496, 280),
                        View = System.Windows.Forms.View.Details,
                        FullRowSelect = true,
                        MultiSelect = true,  // ★ 允许多选
                        HideSelection = false,
                    };
                    lv.Columns.Add("项目编号", 100);
                    lv.Columns.Add("项目名称", 160);
                    lv.Columns.Add("客户名称", 130);
                    lv.Columns.Add("项目日期", 90);

                    foreach (var p in projects)
                    {
                        string bh = p.ContainsKey("项目编号") ? (p["项目编号"] ?? "").ToString() : "";
                        string mc = p.ContainsKey("项目名称") ? (p["项目名称"] ?? "").ToString() : "";
                        string kh = p.ContainsKey("客户名称") ? (p["客户名称"] ?? "").ToString() : "";
                        string rq = p.ContainsKey("项目日期") ? (p["项目日期"] ?? "").ToString() : "";

                        var item = new System.Windows.Forms.ListViewItem(bh);
                        item.SubItems.Add(mc);
                        item.SubItems.Add(kh);
                        item.SubItems.Add(rq);
                        lv.Items.Add(item);
                    }

                    if (lv.Items.Count > 0)
                        lv.Items[0].Selected = true;

                    dlg.Controls.Add(lv);

                    // "全选"按钮
                    var btnAll = new System.Windows.Forms.Button
                    {
                        Text = "全选",
                        Location = new System.Drawing.Point(12, 330),
                        Size = new System.Drawing.Size(75, 28),
                    };
                    btnAll.Click += (s2, e2) => { foreach (System.Windows.Forms.ListViewItem it in lv.Items) it.Selected = true; };
                    dlg.Controls.Add(btnAll);

                    var btnOk = new System.Windows.Forms.Button
                    {
                        Text = "导出选中项",
                        DialogResult = System.Windows.Forms.DialogResult.OK,
                        Location = new System.Drawing.Point(330, 330),
                        Size = new System.Drawing.Size(85, 28),
                    };
                    dlg.Controls.Add(btnOk);

                    var btnCancel = new System.Windows.Forms.Button
                    {
                        Text = "取消",
                        DialogResult = System.Windows.Forms.DialogResult.Cancel,
                        Location = new System.Drawing.Point(423, 330),
                        Size = new System.Drawing.Size(85, 28),
                    };
                    dlg.Controls.Add(btnCancel);

                    dlg.AcceptButton = btnOk;
                    dlg.CancelButton = btnCancel;

                    if (dlg.ShowDialog(this) == System.Windows.Forms.DialogResult.OK)
                    {
                        if (lv.SelectedItems != null)
                        {
                            foreach (System.Windows.Forms.ListViewItem it in lv.SelectedItems)
                            {
                                result.Add(it.Text);  // 第 0 列就是项目编号
                            }
                        }
                    }
                }
            }
            catch (Exception ex)
            {
                Log("[项目导出] 弹选择对话框失败: " + ex.Message);
            }
            return result;
        }

        private string PickProjectDialog(System.Collections.Generic.List<System.Collections.Generic.Dictionary<string, object>> projects)
        {
            try
            {
                // 用一个临时 Form 做选择对话框
                using (var dlg = new System.Windows.Forms.Form
                {
                    Text = "选择要导出的项目",
                    StartPosition = FormStartPosition.CenterParent,
                    FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedDialog,
                    MaximizeBox = false,
                    MinimizeBox = false,
                    ClientSize = new System.Drawing.Size(520, 360),
                })
                {
                    var lbl = new System.Windows.Forms.Label
                    {
                        Text = "请选择要导出的项目:",
                        Location = new System.Drawing.Point(12, 12),
                        Size = new System.Drawing.Size(496, 23),
                        TextAlign = System.Drawing.ContentAlignment.MiddleLeft,
                    };
                    dlg.Controls.Add(lbl);

                    var lv = new System.Windows.Forms.ListView
                    {
                        Location = new System.Drawing.Point(12, 40),
                        Size = new System.Drawing.Size(496, 260),
                        View = System.Windows.Forms.View.Details,
                        FullRowSelect = true,
                        MultiSelect = false,
                        HideSelection = false,
                    };
                    lv.Columns.Add("项目编号", 100);
                    lv.Columns.Add("项目名称", 160);
                    lv.Columns.Add("客户名称", 130);
                    lv.Columns.Add("项目日期", 90);

                    foreach (var p in projects)
                    {
                        string bh = p.ContainsKey("项目编号") ? (p["项目编号"] ?? "").ToString() : "";
                        string mc = p.ContainsKey("项目名称") ? (p["项目名称"] ?? "").ToString() : "";
                        string kh = p.ContainsKey("客户名称") ? (p["客户名称"] ?? "").ToString() : "";
                        string rq = p.ContainsKey("项目日期") ? (p["项目日期"] ?? "").ToString() : "";

                        var item = new System.Windows.Forms.ListViewItem(bh);
                        item.SubItems.Add(mc);
                        item.SubItems.Add(kh);
                        item.SubItems.Add(rq);
                        lv.Items.Add(item);
                    }

                    if (lv.Items.Count > 0)
                        lv.Items[0].Selected = true;

                    dlg.Controls.Add(lv);

                    var btnOk = new System.Windows.Forms.Button
                    {
                        Text = "导出选中项",
                        DialogResult = System.Windows.Forms.DialogResult.OK,
                        Location = new System.Drawing.Point(330, 310),
                        Size = new System.Drawing.Size(85, 28),
                    };
                    dlg.Controls.Add(btnOk);

                    var btnCancel = new System.Windows.Forms.Button
                    {
                        Text = "取消",
                        DialogResult = System.Windows.Forms.DialogResult.Cancel,
                        Location = new System.Drawing.Point(423, 310),
                        Size = new System.Drawing.Size(85, 28),
                    };
                    dlg.Controls.Add(btnCancel);

                    dlg.AcceptButton = btnOk;
                    dlg.CancelButton = btnCancel;

                    // 双击列表项也相当于点确定
                    lv.DoubleClick += (s2, e2) => { dlg.DialogResult = System.Windows.Forms.DialogResult.OK; };

                    if (dlg.ShowDialog(this) == System.Windows.Forms.DialogResult.OK)
                    {
                        if (lv.SelectedItems != null && lv.SelectedItems.Count > 0)
                        {
                            return lv.SelectedItems[0].Text;  // 第 0 列就是项目编号
                        }
                    }
                }
            }
            catch (Exception ex)
            {
                Log("[项目导出] 弹选择对话框失败: " + ex.Message);
            }
            return "";
        }

        // <summary>导入项目:从 .zip 包导入一个项目(冲突时自动改名)。</summary>
        private void button8_Click(object sender, EventArgs e)
        {
            try
            {
                // 默认打开桌面(避免 exe 所在的源码目录无权限)
                string initialDir = "";
                try
                {
                    string desktop = Environment.GetFolderPath(Environment.SpecialFolder.Desktop);
                    if (!string.IsNullOrEmpty(desktop) && System.IO.Directory.Exists(desktop))
                        initialDir = desktop;
                }
                catch { }

                using (var ofd = new OpenFileDialog
                {
                    Title = "导入项目(可多选)",
                    Filter = "项目包 (*.zip)|*.zip",
                    RestoreDirectory = true,
                    Multiselect = true,  // ★ 允许多选 zip 文件
                })
                {
                    if (!string.IsNullOrEmpty(initialDir))
                        ofd.InitialDirectory = initialDir;

                    if (ofd.ShowDialog(this) != DialogResult.OK) return;

                    int totalOk = 0;
                    int totalFail = 0;
                    var importedPids = new System.Collections.Generic.List<string>();

                    foreach (string zipPath in ofd.FileNames)
                    {
                        // 每个 zip 里可能有一个或多个项目(子文件夹)
                        var pids = ImportAllProjectsFromZip(zipPath);
                        if (pids != null && pids.Count > 0)
                        {
                            totalOk += pids.Count;
                            importedPids.AddRange(pids);
                        }
                        else
                        {
                            totalFail++;
                        }
                    }

                    // 刷新项目列表
                    if (totalOk > 0) ReloadProjectsFromDatabase();

                    string msg;
                    if (ofd.FileNames.Length == 1 && totalOk == 1)
                    {
                        msg = "导入成功!\n项目编号:" + importedPids[0];
                    }
                    else
                    {
                        msg = "批量导入完成!\n\n成功导入 " + totalOk + " 个项目";
                        if (totalFail > 0) msg += ",失败 " + totalFail + " 个压缩包";
                        msg += "\n导入的项目:\n" + string.Join("\n", importedPids.ToArray());
                    }
                    MessageBox.Show(this, msg,
                        "导入项目", MessageBoxButtons.OK,
                        totalOk > 0 ? MessageBoxIcon.Information : MessageBoxIcon.Warning);
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(this, "导入失败:\n" + ex.Message,
                    "导入项目", MessageBoxButtons.OK, MessageBoxIcon.Error);
                Log("[项目导入异常] " + ex.Message);
            }
        }

        /// <summary>
        /// 从 zip 包导入所有项目(支持 zip 根目录单个项目 + 子文件夹多个项目)。
        /// 返回成功导入的项目编号列表。
        /// </summary>
        private System.Collections.Generic.List<string> ImportAllProjectsFromZip(string zipPath)
        {
            var result = new System.Collections.Generic.List<string>();
            if (!System.IO.File.Exists(zipPath))
            {
                MessageBox.Show(this, "项目包文件不存在:\n" + zipPath,
                    "导入项目", MessageBoxButtons.OK, MessageBoxIcon.Warning);
                return result;
            }

            // 解压到临时目录
            string tempDir = System.IO.Path.Combine(System.IO.Path.GetTempPath(),
                "成套报价_导入_" + System.Guid.NewGuid().ToString("N"));
            System.IO.Directory.CreateDirectory(tempDir);
            try
            {
                System.IO.Compression.ZipFile.ExtractToDirectory(zipPath, tempDir);

                // 扫描所有含 meta.json 的目录(根目录 + 所有子文件夹)
                var metaDirs = new System.Collections.Generic.List<string>();
                // ① 根目录
                if (System.IO.File.Exists(System.IO.Path.Combine(tempDir, "meta.json")))
                    metaDirs.Add(tempDir);
                // ② 所有子文件夹
                foreach (var sub in System.IO.Directory.GetDirectories(tempDir, "*", System.IO.SearchOption.AllDirectories))
                {
                    if (System.IO.File.Exists(System.IO.Path.Combine(sub, "meta.json")))
                        metaDirs.Add(sub);
                }

                if (metaDirs.Count == 0)
                {
                    MessageBox.Show(this, "无效的项目包:缺少 meta.json\n" + zipPath,
                        "导入项目", MessageBoxButtons.OK, MessageBoxIcon.Warning);
                    return result;
                }

                Log("[项目导入] " + zipPath + " 中发现 " + metaDirs.Count + " 个项目");

                // 逐个导入
                foreach (string dir in metaDirs)
                {
                    string pid = ImportSingleProjectFromDir(dir);
                    if (!string.IsNullOrEmpty(pid)) result.Add(pid);
                }
            }
            finally
            {
                try { System.IO.Directory.Delete(tempDir, true); } catch { }
            }
            return result;
        }

        /// <summary>从指定目录导入单个项目(读 meta.json + db),返回新项目编号。</summary>
        private string ImportSingleProjectFromDir(string dir)
        {
            try
            {
                string metaPath = System.IO.Path.Combine(dir, "meta.json");
                if (!System.IO.File.Exists(metaPath)) return null;

                string metaJson = System.IO.File.ReadAllText(metaPath, new System.Text.UTF8Encoding(false));
                var fields = ParseSimpleJsonFields(metaJson);
                if (fields == null || fields.Count == 0) return null;

                string origPid = fields.ContainsKey("项目编号") ? (fields["项目编号"] ?? "").ToString() : "";
                if (string.IsNullOrWhiteSpace(origPid)) origPid = "未命名";

                // 找 db 文件
                string[] dbFiles = System.IO.Directory.GetFiles(dir, "*.db");
                if (dbFiles.Length == 0) return null;
                string srcDbPath = dbFiles[0];

                // 项目编号冲突时改名
                string newPid = origPid;
                int suffix = 1;
                while (ProjectExists(newPid) || System.IO.File.Exists(GetQuoteDbPath(newPid)))
                {
                    newPid = origPid + "_" + suffix.ToString();
                    suffix++;
                    if (suffix > 999) break;
                }

                // 复制 db
                string dstDbPath = GetQuoteDbPath(newPid);
                string dstDir = System.IO.Path.GetDirectoryName(dstDbPath);
                if (!System.IO.Directory.Exists(dstDir))
                    System.IO.Directory.CreateDirectory(dstDir);
                BackupSQLiteDb(srcDbPath, dstDbPath);

                // 改写库里的项目编号
                try
                {
                    using (var conn = new System.Data.SQLite.SQLiteConnection(GetConnString(dstDbPath)))
                    {
                        conn.Open();
                        using (var chk = new System.Data.SQLite.SQLiteCommand(
                            "SELECT name FROM sqlite_master WHERE type='table' AND name='项目信息';", conn))
                        {
                            object o = chk.ExecuteScalar();
                            if (o != null)
                            {
                                using (var upd = new System.Data.SQLite.SQLiteCommand(
                                    "UPDATE 项目信息 SET 项目编号 = @p;", conn))
                                {
                                    upd.Parameters.AddWithValue("@p", newPid);
                                    upd.ExecuteNonQuery();
                                }
                            }
                        }
                    }
                }
                catch { }

                // 插入项目列表
                fields["项目编号"] = newPid;
                InsertProjectRow(fields);

                Log("[项目导入] " + origPid + " -> " + newPid +
                    (newPid != origPid ? " (原编号:" + origPid + ")" : ""));
                return newPid;
            }
            catch (Exception ex)
            {
                Log("[项目导入] 单个项目导入失败: " + ex.Message);
                return null;
            }
        }

        /// <summary>从 zip 包导入项目,返回新项目编号(失败返回 null)。</summary>
        private string ImportProjectFromZip(string zipPath)
        {
            try
            {
                if (!System.IO.File.Exists(zipPath))
                {
                    MessageBox.Show(this, "项目包文件不存在:\n" + zipPath,
                        "导入项目", MessageBoxButtons.OK, MessageBoxIcon.Warning);
                    return null;
                }

                // 解压到临时目录
                string tempDir = System.IO.Path.Combine(System.IO.Path.GetTempPath(),
                    "成套报价_导入_" + Guid.NewGuid().ToString("N"));
                System.IO.Directory.CreateDirectory(tempDir);
                try
                {
                    System.IO.Compression.ZipFile.ExtractToDirectory(zipPath, tempDir);

                    // 读 meta.json
                    string metaPath = System.IO.Path.Combine(tempDir, "meta.json");
                    if (!System.IO.File.Exists(metaPath))
                    {
                        MessageBox.Show(this, "无效的项目包:缺少 meta.json",
                            "导入项目", MessageBoxButtons.OK, MessageBoxIcon.Warning);
                        return null;
                    }
                    string metaJson = System.IO.File.ReadAllText(metaPath, new System.Text.UTF8Encoding(false));
                    var fields = ParseSimpleJsonFields(metaJson);
                    if (fields == null || fields.Count == 0)
                    {
                        MessageBox.Show(this, "无效的项目包:meta.json 解析失败",
                            "导入项目", MessageBoxButtons.OK, MessageBoxIcon.Warning);
                        return null;
                    }

                    // 原 pid(可能跟现有冲突,后面要改名)
                    string origPid = fields.ContainsKey("项目编号") ? (fields["项目编号"] ?? "").ToString() : "";
                    if (string.IsNullOrWhiteSpace(origPid))
                        origPid = "未命名";

                    // 找包里的 db 文件(只取第一个 .db)
                    string[] dbFiles = System.IO.Directory.GetFiles(tempDir, "*.db");
                    if (dbFiles.Length == 0)
                    {
                        MessageBox.Show(this, "无效的项目包:缺少 .db 文件",
                            "导入项目", MessageBoxButtons.OK, MessageBoxIcon.Warning);
                        return null;
                    }
                    string srcDbPath = dbFiles[0];

                    // 项目编号冲突时改名:在末尾加 _1, _2, ...
                    string newPid = origPid;
                    int suffix = 1;
                    while (ProjectExists(newPid) || System.IO.File.Exists(GetQuoteDbPath(newPid)))
                    {
                        newPid = origPid + "_" + suffix.ToString();
                        suffix++;
                        if (suffix > 999) break;  // 防止死循环
                    }

                    // 把 db 复制到 sjk\bjb\项目<newPid>.db
                    string dstDbPath = GetQuoteDbPath(newPid);
                    string dstDir = System.IO.Path.GetDirectoryName(dstDbPath);
                    if (!System.IO.Directory.Exists(dstDir))
                        System.IO.Directory.CreateDirectory(dstDir);
                    // 用 SQLite Backup API 复制(避免目标路径被连接池锁住)
                    BackupSQLiteDb(srcDbPath, dstDbPath);

                    // 改写库里的"项目信息"表的项目编号字段(同步成新 pid)
                    try
                    {
                        using (var conn = new System.Data.SQLite.SQLiteConnection(GetConnString(dstDbPath)))
                        {
                            conn.Open();
                            using (var chk = new System.Data.SQLite.SQLiteCommand(
                                "SELECT name FROM sqlite_master WHERE type='table' AND name='项目信息';", conn))
                            {
                                object o = chk.ExecuteScalar();
                                if (o != null)
                                {
                                    using (var upd = new System.Data.SQLite.SQLiteCommand(
                                        "UPDATE 项目信息 SET 项目编号 = @p;", conn))
                                    {
                                        upd.Parameters.AddWithValue("@p", newPid);
                                        upd.ExecuteNonQuery();
                                    }
                                }
                            }
                        }
                    }
                    catch { /* 项目信息表更新失败不阻断 */ }

                    // 把项目元数据 INSERT 到项目列表(用新 pid)
                    fields["项目编号"] = newPid;
                    InsertProjectRow(fields);

                    // 刷新项目列表显示
                    ReloadProjectsFromDatabase();

                    Log("[项目导入] " + zipPath + " -> " + newPid +
                        (newPid != origPid ? " (原编号:" + origPid + ")" : ""));
                    return newPid;
                }
                finally
                {
                    try { System.IO.Directory.Delete(tempDir, true); } catch { }
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(this, "导入失败:\n" + ex.Message,
                    "导入项目", MessageBoxButtons.OK, MessageBoxIcon.Error);
                Log("[项目导入异常] " + ex.Message);
                return null;
            }
        }

        /// <summary>
        /// 取当前要导出/导入操作的项目编号。
        /// 优先级:① 项目列表(advancedDataGridView6)中用户选中的行
        ///       ② 已双击进入的当前项目(_currentProjectId)
        /// </summary>
        private string GetCurrentProjectIdFromGrid()
        {
            try
            {
                var grid = this.advancedDataGridView6;
                if (grid != null && grid.Columns.Contains("项目编号"))
                {
                    // ① CurrentRow(无论 SelectionMode,只要用户在 grid 上点击过,这就是当前行)
                    if (grid.CurrentRow != null && grid.CurrentRow.Index >= 0
                        && grid.CurrentRow.Index < grid.Rows.Count)
                    {
                        object v = grid.CurrentRow.Cells["项目编号"].Value;
                        if (v != null && v != DBNull.Value)
                        {
                            string s = v.ToString();
                            if (!string.IsNullOrWhiteSpace(s)) return s;
                        }
                    }

                    // ② SelectedRows(RowHeaderSelect 模式下点行头会进 SelectedRows)
                    if (grid.SelectedRows != null && grid.SelectedRows.Count > 0)
                    {
                        foreach (DataGridViewRow sr in grid.SelectedRows)
                        {
                            if (sr.Index < 0) continue;
                            object v = sr.Cells["项目编号"].Value;
                            if (v != null && v != DBNull.Value)
                            {
                                string s = v.ToString();
                                if (!string.IsNullOrWhiteSpace(s)) return s;
                            }
                        }
                    }

                    // ③ SelectedCells 回退:单元格选中模式下,从选中单元格反查所属行
                    if (grid.SelectedCells != null && grid.SelectedCells.Count > 0)
                    {
                        int rowIdx = grid.SelectedCells[0].RowIndex;
                        if (rowIdx >= 0 && rowIdx < grid.Rows.Count)
                        {
                            object v = grid.Rows[rowIdx].Cells["项目编号"].Value;
                            if (v != null && v != DBNull.Value)
                            {
                                string s = v.ToString();
                                if (!string.IsNullOrWhiteSpace(s)) return s;
                            }
                        }
                    }

                    // ④ FirstDisplayedScrollingRowIndex(用户滚动到的那行)
                    if (grid.FirstDisplayedScrollingRowIndex >= 0
                        && grid.FirstDisplayedScrollingRowIndex < grid.Rows.Count)
                    {
                        object v = grid.Rows[grid.FirstDisplayedScrollingRowIndex].Cells["项目编号"].Value;
                        if (v != null && v != DBNull.Value)
                        {
                            string s = v.ToString();
                            if (!string.IsNullOrWhiteSpace(s)) return s;
                        }
                    }
                }
            }
            catch { }

            // ⑤ 兜底:已经双击进入的项目
            if (!string.IsNullOrWhiteSpace(_currentProjectId))
                return _currentProjectId;

            return "";
        }

        /// <summary>从项目表读取指定项目编号那一行的所有字段(字典)。</summary>
        private System.Collections.Generic.Dictionary<string, object> ReadProjectMetaData(string pid)
        {
            var dict = new System.Collections.Generic.Dictionary<string, object>(StringComparer.Ordinal);
            try
            {
                string dbPath = GetDbFullPath(ProjectsDbPath);
                using (var conn = new System.Data.SQLite.SQLiteConnection(GetConnString(dbPath)))
                {
                    conn.Open();
                    using (var cmd = new System.Data.SQLite.SQLiteCommand(
                        "SELECT * FROM " + ProjectsTableName + " WHERE 项目编号 = @p LIMIT 1;", conn))
                    {
                        cmd.Parameters.AddWithValue("@p", pid);
                        using (var rd = cmd.ExecuteReader())
                        {
                            if (!rd.Read()) return null;
                            for (int i = 0; i < rd.FieldCount; i++)
                            {
                                string col = rd.GetName(i);
                                object v = rd.GetValue(i);
                                if (v == null || v == DBNull.Value) v = "";
                                dict[col] = v;
                            }
                        }
                    }
                }
            }
            catch { return null; }
            return dict;
        }

        /// <summary>把项目元数据字段字典插入到项目表(过滤不存在的列)。</summary>
        private void InsertProjectRow(System.Collections.Generic.Dictionary<string, string> fields)
        {
            try
            {
                string dbPath = GetDbFullPath(ProjectsDbPath);
                using (var conn = new System.Data.SQLite.SQLiteConnection(GetConnString(dbPath)))
                {
                    conn.Open();
                    // 读项目表实际有的列
                    var tableCols = new System.Collections.Generic.HashSet<string>(StringComparer.Ordinal);
                    using (var infoCmd = new System.Data.SQLite.SQLiteCommand(
                        "PRAGMA table_info(" + ProjectsTableName + ");", conn))
                    using (var rd = infoCmd.ExecuteReader())
                    {
                        while (rd.Read())
                            tableCols.Add(rd.GetString(1));
                    }

                    // 只插入项目表有的列
                    var colNames = new System.Collections.Generic.List<string>();
                    var paramNames = new System.Collections.Generic.List<string>();
                    foreach (var kv in fields)
                    {
                        if (tableCols.Contains(kv.Key))
                        {
                            colNames.Add(kv.Key);
                            paramNames.Add("@" + kv.Key);
                        }
                    }
                    if (colNames.Count == 0) return;

                    string sql = "INSERT INTO " + ProjectsTableName + " (" +
                                 string.Join(", ", colNames.ToArray()) + ") VALUES (" +
                                 string.Join(", ", paramNames.ToArray()) + ");";
                    using (var cmd = new System.Data.SQLite.SQLiteCommand(sql, conn))
                    {
                        foreach (string col in colNames)
                            cmd.Parameters.AddWithValue("@" + col, fields[col] ?? "");
                        cmd.ExecuteNonQuery();
                    }
                }
            }
            catch (Exception ex)
            {
                Log("[项目导入] 插入项目表失败: " + ex.Message);
            }
        }

        /// <summary>把字符串转成合法文件名(替换非法字符为下划线)。</summary>
        private static string MakeSafeFileName(string s)
        {
            if (string.IsNullOrEmpty(s)) return "未命名";
            string r = s;
            char[] invalid = System.IO.Path.GetInvalidFileNameChars();
            foreach (char c in invalid) r = r.Replace(c, '_');
            return r;
        }

        /// <summary>简单的 JSON 字符串转义。</summary>
        private static string EscapeJsonString(string s)
        {
            if (s == null) return "";
            return s.Replace("\\", "\\\\").Replace("\"", "\\\"")
                    .Replace("\r", "\\r").Replace("\n", "\\n").Replace("\t", "\\t");
        }

        /// <summary>
        /// 极简 JSON 解析:只支持读 { "字段": { "k":"v", "k2":"v2" }, "项目编号":"xxx" } 这种结构。
        /// 返回 "字段" 字典 + "项目编号" 顶层键合并到一起(用于导入元数据)。
        /// 不支持数组、嵌套对象等(本场景够用)。
        /// </summary>
        private static System.Collections.Generic.Dictionary<string, string> ParseSimpleJsonFields(string json)
        {
            var dict = new System.Collections.Generic.Dictionary<string, string>(StringComparer.Ordinal);
            if (string.IsNullOrWhiteSpace(json)) return dict;
            try
            {
                // 用正则提取所有 "键": "值" 配对(不区分是否嵌套,统统拍平)
                // 值里可能含转义 \" \\ 等,贪婪到第一个未转义的 "
                string pattern = "\"((?:[^\"\\\\]|\\\\.)*)\"\\s*:\\s*\"((?:[^\"\\\\]|\\\\.)*)\"";
                var rx = new System.Text.RegularExpressions.Regex(pattern);
                var matches = rx.Matches(json);
                foreach (System.Text.RegularExpressions.Match m in matches)
                {
                    string key = UnescapeJsonString(m.Groups[1].Value);
                    string val = UnescapeJsonString(m.Groups[2].Value);
                    if (!dict.ContainsKey(key))
                        dict[key] = val;
                }
                return dict;
            }
            catch
            {
                return dict;
            }
        }

        /// <summary>反转 JSON 字符串的转义。</summary>
        private static string UnescapeJsonString(string s)
        {
            if (string.IsNullOrEmpty(s)) return s;
            return s.Replace("\\\"", "\"").Replace("\\\\", "\\")
                    .Replace("\\n", "\n").Replace("\\r", "\r").Replace("\\t", "\t");
        }

    }
}