using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
using UnityEngine;
using System.Threading.Tasks;
using System.Linq;
using System.Globalization;

/// <summary>
/// 跨平台数据导出服务
/// 支持BFI测试记录、折线图和历史数据的导出
/// </summary>
public class DataExportService : IDataExportService
{
    private const string EXPORT_FOLDER = "DCX_Export";
    private const string HISTORY_FOLDER = "History";
    private const float ANDROID_USB_CACHE_SECONDS = 2f;
    private string _lastExportedFilePath;
    private string _lastErrorMessage;
    private string _cachedAndroidUsbDirectory;
    private bool _cachedAndroidUsbDirectoryWritable;
    private float _cachedAndroidUsbDirectoryTime;

    public string GetLastErrorMessage()
    {
        return _lastErrorMessage;
    }

    private void ClearLastError()
    {
        _lastErrorMessage = null;
    }

    private void SetLastError(string message)
    {
        _lastErrorMessage = message;
        if (!string.IsNullOrEmpty(message))
        {
            Debug.LogWarning(message);
        }
    }
    
    /// <summary>
    /// 导出数据到USB（跨平台实现），content为要写入的文件内容
    /// </summary>
    public bool ExportToUsb(string suggestedFilename, string content = null)
    {
        try
        {
            ClearLastError();
            #if UNITY_ANDROID && !UNITY_EDITOR
            return ExportToAndroidStorage(suggestedFilename, content);
            #else
            return ExportToEditorPath(suggestedFilename, content);
            #endif
        }
        catch (Exception ex)
        {
            SetLastError($"数据导出失败: {ex.Message}");
            return false;
        }
    }
    
    /// <summary>
    /// 导出多个历史记录
    /// </summary>
    public bool ExportHistoryRecords(List<BFITestRecord> records, ExportFormat format = ExportFormat.TXT)
    {
        try
        {
            ClearLastError();
            if (records == null || records.Count == 0)
            {
                SetLastError("没有可导出的历史记录");
                return false;
            }

            var emptyDetailRecords = records
                .Where(record => record == null || record.DataPoints == null || record.DataPoints.Count == 0)
                .ToList();
            if (emptyDetailRecords.Count > 0)
            {
                string names = string.Join("、", emptyDetailRecords
                    .Select(GetRecordDisplayName)
                    .Take(3));
                if (emptyDetailRecords.Count > 3)
                {
                    names += "等";
                }

                SetLastError($"所选BFI记录缺少明细数据，无法导出：{names}");
                return false;
            }

            if (records.Sum(record => GetValidDataPoints(record).Count) == 0)
            {
                SetLastError("所选BFI记录没有有效数据点，无法导出");
                return false;
            }

            if (!CheckExportPermissions())
            {
                return false;
            }

            #if UNITY_ANDROID && !UNITY_EDITOR
            if (HasAndroidSafUsbDirectoryPermission())
            {
                if (TryExportHistoryRecordsWithAndroidSaf(records, format))
                {
                    return true;
                }

                if (!string.IsNullOrEmpty(_lastErrorMessage))
                {
                    return false;
                }
            }
            #endif
            
            string filename = $"BFI_History_{format}_{DateTime.Now:yyyyMMdd_HHmmss_fff}";
            string exportPath = GetExportPath(filename);
            if (string.IsNullOrEmpty(exportPath))
            {
                SetLastError("未找到可写入的U盘导出目录");
                return false;
            }

            switch (format)
            {
                case ExportFormat.TXT:
                    return ExportHistoryToTXT(records, exportPath);
                case ExportFormat.CSV:
                    return ExportHistoryToCSV(records, exportPath);
                case ExportFormat.PDF:
                    return ExportHistoryToPDF(records, exportPath);
                default:
                    return ExportHistoryToTXT(records, exportPath);
            }
        }
        catch (Exception ex)
        {
            SetLastError($"历史记录导出失败: {ex.Message}");
            return false;
        }
    }

    #if UNITY_ANDROID && !UNITY_EDITOR
    private bool TryExportHistoryRecordsWithAndroidSaf(List<BFITestRecord> records, ExportFormat format)
    {
        try
        {
            if (!HasAndroidSafUsbDirectoryPermission())
            {
                if (RequestAndroidSafUsbDirectoryPermission())
                {
                    SetLastError("请在弹出的文件选择器中选择 U S B 根目录并授权，然后重新点击导出");
                }
                return false;
            }

            string fileName = $"BFI_History_{format}_{DateTime.Now:yyyyMMdd_HHmmss_fff}{GetExportFileExtension(format)}";
            bool success;
            if (format == ExportFormat.PDF)
            {
                byte[] pdfBytes = BuildSimplePdfBytes(BuildPdfReportLines(records));
                success = AndroidSafWriteBytesFile(fileName, pdfBytes);
            }
            else
            {
                string content = BuildHistoryExportContent(records, format);
                if (string.IsNullOrEmpty(content))
                {
                    SetLastError("导出内容为空");
                    return false;
                }

                success = AndroidSafWriteTextFile(fileName, content);
            }

            if (success)
            {
                _lastExportedFilePath = $"U S B/DCX_Export/{fileName}";
                Debug.Log($"历史记录已通过U盘目录授权导出: {_lastExportedFilePath}");
                return true;
            }

            ClearAndroidSafUsbDirectoryPermission();
            if (RequestAndroidSafUsbDirectoryPermission())
            {
                SetLastError("U盘目录授权已失效或当前U盘不可写，已重新打开授权窗口。请选择 U S B 根目录并授权后再次导出");
            }
            return false;
        }
        catch (Exception ex)
        {
            SetLastError($"U盘授权写入失败: {ex.Message}");
            return false;
        }
    }

    private string GetExportFileExtension(ExportFormat format)
    {
        switch (format)
        {
            case ExportFormat.CSV:
                return "_history.csv";
            case ExportFormat.PDF:
                return "_history.pdf";
            case ExportFormat.TXT:
            default:
                return "_history.txt";
        }
    }

    private string BuildHistoryExportContent(List<BFITestRecord> records, ExportFormat format)
    {
        switch (format)
        {
            case ExportFormat.CSV:
                return BuildHistoryCsvContent(records);
            case ExportFormat.TXT:
            default:
                return BuildHistoryTxtContent(records);
        }
    }

    private string BuildHistoryTxtContent(List<BFITestRecord> records)
    {
        var reportBuilder = new StringBuilder();
        reportBuilder.AppendLine("BFI测试历史报告");
        reportBuilder.AppendLine($"生成时间: {DateTime.Now:yyyy-MM-dd HH:mm:ss}");
        reportBuilder.AppendLine($"记录数量: {records.Count}");
        reportBuilder.AppendLine();

        foreach (var record in records)
        {
            reportBuilder.AppendLine(GenerateBFIReportContent(record));
            reportBuilder.AppendLine("" + new string('=', 50));
        }

        return reportBuilder.ToString();
    }

    private string BuildHistoryCsvContent(List<BFITestRecord> records)
    {
        var csvBuilder = new StringBuilder();
        csvBuilder.AppendLine("测试名称,患者姓名,住院号,性别,年龄,身高(cm),体重(kg),开始时间,结束时间,时间戳,BFI值,状态,备注");

        foreach (var record in records)
        {
            DateTime startTime = GetEffectiveStartTime(record);
            DateTime endTime = GetEffectiveEndTime(record, startTime);
            var validPoints = GetValidDataPoints(record);

            string patientName = EscapeCsv(GetPatientName(record));
            string patientId = EscapeCsv(GetPatientId(record));
            string patientGender = EscapeCsv(GetPatientGender(record));
            string patientAge = FormatPatientAge(record.PatientAge);
            string patientHeight = FormatPatientHeight(record.PatientHeight);
            string patientWeight = FormatPatientWeight(record.PatientWeight);

            if (validPoints.Count == 0)
            {
                csvBuilder.AppendLine($"{EscapeCsv(record.TestName)},{patientName},{patientId},{patientGender},{patientAge},{patientHeight},{patientWeight},{startTime:yyyy-MM-dd HH:mm:ss},{endTime:yyyy-MM-dd HH:mm:ss},,,无有效数据点,");
                continue;
            }

            foreach (var dataPoint in validPoints)
            {
                csvBuilder.AppendLine($"{EscapeCsv(record.TestName)},{patientName},{patientId},{patientGender},{patientAge},{patientHeight},{patientWeight},{startTime:yyyy-MM-dd HH:mm:ss},{endTime:yyyy-MM-dd HH:mm:ss},{dataPoint.Timestamp:yyyy-MM-dd HH:mm:ss},{dataPoint.BFI:F2},{EscapeCsv(dataPoint.Status)},{EscapeCsv(dataPoint.Notes)}");
            }
        }

        return csvBuilder.ToString();
    }

    private bool HasAndroidSafUsbDirectoryPermission()
    {
        using (var unityClass = new AndroidJavaClass("com.unity3d.player.UnityPlayer"))
        using (var currentActivity = unityClass.GetStatic<AndroidJavaObject>("currentActivity"))
        using (var usbAccess = new AndroidJavaClass("com.dcx.ruiyiweiux.UsbStorageAccess"))
        {
            return usbAccess.CallStatic<bool>("hasPersistedUsbDirectory", currentActivity);
        }
    }

    private bool RequestAndroidSafUsbDirectoryPermission()
    {
        try
        {
            using (var unityClass = new AndroidJavaClass("com.unity3d.player.UnityPlayer"))
            using (var currentActivity = unityClass.GetStatic<AndroidJavaObject>("currentActivity"))
            using (var usbAccess = new AndroidJavaClass("com.dcx.ruiyiweiux.UsbStorageAccess"))
            {
                usbAccess.CallStatic("requestUsbDirectoryPermission", currentActivity);
                return true;
            }
        }
        catch (Exception ex)
        {
            SetLastError($"无法打开U盘目录授权窗口: {ex.Message}");
            return false;
        }
    }

    private void ClearAndroidSafUsbDirectoryPermission()
    {
        using (var unityClass = new AndroidJavaClass("com.unity3d.player.UnityPlayer"))
        using (var currentActivity = unityClass.GetStatic<AndroidJavaObject>("currentActivity"))
        using (var usbAccess = new AndroidJavaClass("com.dcx.ruiyiweiux.UsbStorageAccess"))
        {
            usbAccess.CallStatic("clearPersistedUsbDirectory", currentActivity);
        }
    }

    private bool AndroidSafWriteTextFile(string fileName, string content)
    {
        using (var unityClass = new AndroidJavaClass("com.unity3d.player.UnityPlayer"))
        using (var currentActivity = unityClass.GetStatic<AndroidJavaObject>("currentActivity"))
        using (var usbAccess = new AndroidJavaClass("com.dcx.ruiyiweiux.UsbStorageAccess"))
        {
            return usbAccess.CallStatic<bool>("writeTextFile", currentActivity, fileName, content);
        }
    }

    private bool AndroidSafWriteBytesFile(string fileName, byte[] bytes)
    {
        using (var unityClass = new AndroidJavaClass("com.unity3d.player.UnityPlayer"))
        using (var currentActivity = unityClass.GetStatic<AndroidJavaObject>("currentActivity"))
        using (var usbAccess = new AndroidJavaClass("com.dcx.ruiyiweiux.UsbStorageAccess"))
        {
            return usbAccess.CallStatic<bool>("writeBytesFile", currentActivity, fileName, bytes);
        }
    }

    private int GetAndroidSdkInt()
    {
        using (var buildVersion = new AndroidJavaClass("android.os.Build$VERSION"))
        {
            return buildVersion.GetStatic<int>("SDK_INT");
        }
    }
    #endif
    
    #region 平台特定实现
    
    #if UNITY_ANDROID && !UNITY_EDITOR
    
    /// <summary>
    /// Android平台导出到存储
    /// 导出路径：/sdcard/Download/DCX_Export/
    /// </summary>
    private bool ExportToAndroidStorage(string filename, string content = null)
    {
        try
        {
            if (GetAndroidSdkInt() >= 29)
            {
                if (HasAndroidSafUsbDirectoryPermission())
                {
                    bool safSuccess = AndroidSafWriteTextFile(filename, content ?? string.Empty);
                    if (safSuccess)
                    {
                        _lastExportedFilePath = $"U S B/DCX_Export/{filename}";
                        Debug.Log($"Android: 文件已通过U盘目录授权写入 {_lastExportedFilePath}");
                        return true;
                    }

                    ClearAndroidSafUsbDirectoryPermission();
                    if (RequestAndroidSafUsbDirectoryPermission())
                    {
                        SetLastError("U盘目录授权已失效或当前U盘不可写，已重新打开授权窗口。请选择 U S B 根目录并授权后再次导出");
                    }
                    return false;
                }
            }

            string exportDir = GetExportDirectory();
            if (string.IsNullOrEmpty(exportDir))
            {
                if (GetAndroidSdkInt() >= 29 && RequestAndroidSafUsbDirectoryPermission())
                {
                    SetLastError("未检测到可直接写入的U盘路径。请在弹出的文件选择器中选择 U S B 根目录并授权，然后重新点击导出");
                }
                else
                {
                    SetLastError("未检测到可写入的U盘，请插入U盘后重试");
                }
                return false;
            }

            exportDir = EnsureExportDirectoryWithRootFolder(exportDir);
            if (!Directory.Exists(exportDir))
            {
                Directory.CreateDirectory(exportDir);
            }

            string fullPath = Path.Combine(exportDir, filename);

            // 写入文件内容
            if (content != null)
            {
                File.WriteAllText(fullPath, content, Encoding.UTF8);
                Debug.Log($"Android: 文件已写入 {fullPath}");
                _lastExportedFilePath = fullPath;
            }
            else
            {
                Debug.Log($"Android: 导出目录已准备 {fullPath}（无内容写入）");
            }

            // 通知媒体扫描器更新文件，使其在文件管理器中可见
            using (var unityClass = new AndroidJavaClass("com.unity3d.player.UnityPlayer"))
            using (var currentActivity = unityClass.GetStatic<AndroidJavaObject>("currentActivity"))
            {
                NotifyMediaScanner(currentActivity, fullPath);
            }

            return true;
        }
        catch (Exception ex)
        {
            SetLastError($"Android导出失败: {ex.Message}");
            return false;
        }
    }
    
    /// <summary>
    /// 通知Android媒体扫描器更新文件
    /// </summary>
    private void NotifyMediaScanner(AndroidJavaObject activity, string filePath)
    {
        try
        {
            var intent = new AndroidJavaObject("android.content.Intent");
            intent.Call<AndroidJavaObject>("setAction", "android.intent.action.MEDIA_SCANNER_SCAN_FILE");
            
            var uri = new AndroidJavaClass("android.net.Uri");
            var fileUri = uri.CallStatic<AndroidJavaObject>("parse", $"file://{filePath}");
            intent.Call<AndroidJavaObject>("setData", fileUri);
            
            activity.Call("sendBroadcast", intent);
        }
        catch (Exception ex)
        {
            Debug.LogWarning($"媒体扫描器通知失败: {ex.Message}");
        }
    }
    
    #else
    
    /// <summary>
    /// 编辑器/Windows模式导出
    /// </summary>
    private bool ExportToEditorPath(string filename, string content = null)
    {
        try
        {
            string exportDir = EnsureExportDirectoryWithRootFolder(GetExportDirectory());
            
            if (!Directory.Exists(exportDir))
            {
                Directory.CreateDirectory(exportDir);
            }
            
            string fullPath = Path.Combine(exportDir, filename);
            
            // 写入文件内容
            if (content != null)
            {
                File.WriteAllText(fullPath, content, Encoding.UTF8);
                Debug.Log($"编辑器: 文件已写入 {fullPath}");
                _lastExportedFilePath = fullPath;
            }
            else
            {
                Debug.Log($"编辑器: 导出目录已准备 {fullPath}（无内容写入）");
            }
            
            return true;
        }
        catch (Exception ex)
        {
            Debug.LogError($"编辑器导出失败: {ex.Message}");
            return false;
        }
    }
    
    /// <summary>
    /// 获取Windows平台USB设备驱动器列表
    /// </summary>
    private List<string> GetUsbDrives()
    {
        var usbDrives = new List<string>();
        #if UNITY_STANDALONE_WIN || UNITY_EDITOR_WIN
        try
        {
            foreach (var drive in System.IO.DriveInfo.GetDrives())
            {
                if (!drive.IsReady)
                {
                    continue;
                }

                string root = drive.RootDirectory.FullName;
                bool isRemovable = drive.DriveType == System.IO.DriveType.Removable;
                bool hasDcxExportFolder = Directory.Exists(Path.Combine(root, EXPORT_FOLDER));
                bool isSystemDrive = string.Equals(
                    Path.GetPathRoot(Environment.GetFolderPath(Environment.SpecialFolder.Windows)),
                    root,
                    StringComparison.OrdinalIgnoreCase);

                if (isRemovable || (!isSystemDrive && hasDcxExportFolder))
                {
                    usbDrives.Add(root);
                }
            }
        }
        catch (Exception ex)
        {
            Debug.LogWarning($"获取USB驱动器失败: {ex.Message}");
        }
        #endif
        return usbDrives;
    }
    
    #endif
    
    #endregion

    #if UNITY_ANDROID && !UNITY_EDITOR
    private string GetAndroidUsbExportDirectory(bool requireWritable)
    {
        if (Application.platform == RuntimePlatform.Android &&
            Time.unscaledTime - _cachedAndroidUsbDirectoryTime <= ANDROID_USB_CACHE_SECONDS &&
            !string.IsNullOrEmpty(_cachedAndroidUsbDirectory))
        {
            if (!requireWritable || _cachedAndroidUsbDirectoryWritable)
            {
                return _cachedAndroidUsbDirectory;
            }
        }

        string firstCandidate = null;

        foreach (var root in GetAndroidUsbCandidateRoots())
        {
            if (string.IsNullOrEmpty(root))
            {
                continue;
            }

            string exportDir = EnsureExportDirectoryWithRootFolder(root);
            if (string.IsNullOrEmpty(firstCandidate))
            {
                firstCandidate = exportDir;
            }

            if (IsWritableDirectory(exportDir))
            {
                Debug.Log($"检测到可写U盘导出目录: {exportDir}");
                _cachedAndroidUsbDirectory = exportDir;
                _cachedAndroidUsbDirectoryWritable = true;
                _cachedAndroidUsbDirectoryTime = Time.unscaledTime;
                return exportDir;
            }
        }

        _cachedAndroidUsbDirectory = firstCandidate;
        _cachedAndroidUsbDirectoryWritable = false;
        _cachedAndroidUsbDirectoryTime = Time.unscaledTime;
        return requireWritable ? null : firstCandidate;
    }

    private IEnumerable<string> GetAndroidUsbCandidateRoots()
    {
        var roots = new List<string>();
        AddAndroidUsbRootsFromStorageManager(roots);
        AddAndroidUsbRootsFromEnvironment(roots);

        AddAndroidUsbRoot(roots, "/storage/USB");
        AddAndroidUsbRoot(roots, "/storage/U S B");
        AddAndroidUsbRoot(roots, "/storage/usbotg");
        AddAndroidUsbRoot(roots, "/storage/usb");
        AddAndroidUsbRoot(roots, "/storage/udisk");
        AddAndroidUsbRoot(roots, "/storage/udisk1");
        AddAndroidUsbRoot(roots, "/mnt/usb");
        AddAndroidUsbRoot(roots, "/mnt/udisk");
        AddAndroidUsbRoot(roots, "/mnt/usb_storage/USB_DISK0");
        AddAndroidUsbRoot(roots, "/mnt/usb_storage/USB_DISK1");

        return roots;
    }

    private void AddAndroidUsbRootsFromStorageManager(List<string> roots)
    {
        try
        {
            using (var unityClass = new AndroidJavaClass("com.unity3d.player.UnityPlayer"))
            using (var currentActivity = unityClass.GetStatic<AndroidJavaObject>("currentActivity"))
            using (var context = currentActivity.Call<AndroidJavaObject>("getApplicationContext"))
            {
                var storageManager = context.Call<AndroidJavaObject>("getSystemService", "storage");
                if (storageManager == null)
                {
                    return;
                }

                var volumes = storageManager.Call<AndroidJavaObject>("getStorageVolumes");
                if (volumes == null)
                {
                    return;
                }

                int count = volumes.Call<int>("size");
                for (int i = 0; i < count; i++)
                {
                    using (var volume = volumes.Call<AndroidJavaObject>("get", i))
                    {
                        if (volume == null)
                        {
                            continue;
                        }

                        bool isPrimary = SafeCallBool(volume, "isPrimary");
                        bool isRemovable = SafeCallBool(volume, "isRemovable");
                        if (isPrimary || !isRemovable)
                        {
                            continue;
                        }

                        string description = TryGetStorageVolumeDescription(volume, context);
                        string path = TryGetStorageVolumeDirectory(volume);
                        if (!string.IsNullOrEmpty(path) &&
                            IsLikelyAndroidUsbRoot(description, path))
                        {
                            Debug.Log($"检测到可移动存储卷: {description}, 路径: {path}");
                            AddAndroidUsbRoot(roots, path);
                        }
                    }
                }
            }
        }
        catch (Exception ex)
        {
            Debug.LogWarning($"通过StorageManager扫描U盘失败: {ex.Message}");
        }
    }

    private bool SafeCallBool(AndroidJavaObject target, string methodName)
    {
        try
        {
            return target != null && target.Call<bool>(methodName);
        }
        catch
        {
            return false;
        }
    }

    private string TryGetStorageVolumeDescription(AndroidJavaObject volume, AndroidJavaObject context)
    {
        try
        {
            return volume.Call<string>("getDescription", context);
        }
        catch
        {
            return null;
        }
    }

    private string TryGetStorageVolumeDirectory(AndroidJavaObject volume)
    {
        try
        {
            using (var directory = volume.Call<AndroidJavaObject>("getDirectory"))
            {
                string path = directory?.Call<string>("getAbsolutePath");
                if (!string.IsNullOrEmpty(path))
                {
                    return path;
                }
            }
        }
        catch
        {
            // Android 10及以下没有公开getDirectory，继续尝试厂商/旧系统常见方法。
        }

        try
        {
            string path = volume.Call<string>("getPath");
            if (!string.IsNullOrEmpty(path))
            {
                return path;
            }
        }
        catch
        {
            return null;
        }

        return null;
    }

    private void AddAndroidUsbRootsFromEnvironment(List<string> roots)
    {
        AddAndroidUsbRootsFromEnvironmentValue(roots, Environment.GetEnvironmentVariable("SECONDARY_STORAGE"));
        AddAndroidUsbRootsFromEnvironmentValue(roots, Environment.GetEnvironmentVariable("EXTERNAL_STORAGE"));
    }

    private void AddAndroidUsbRootsFromEnvironmentValue(List<string> roots, string value)
    {
        if (string.IsNullOrEmpty(value))
        {
            return;
        }

        foreach (var path in value.Split(new[] { ':' }, StringSplitOptions.RemoveEmptyEntries))
        {
            AddAndroidUsbRoot(roots, path);
        }
    }

    private bool IsLikelyAndroidUsbRoot(string name, string path)
    {
        if (string.IsNullOrEmpty(name) || string.IsNullOrEmpty(path))
        {
            return false;
        }

        string lowerName = name.ToLowerInvariant();
        string lowerPath = path.ToLowerInvariant();
        string normalizedName = lowerName.Replace(" ", string.Empty)
            .Replace("_", string.Empty)
            .Replace("-", string.Empty);

        if (lowerName == "emulated" || lowerName == "self" || lowerName == "sdcard0" || lowerName == "sdcard")
        {
            return false;
        }

        if (lowerPath.Contains("/android/data") || lowerPath.Contains("/obb"))
        {
            return false;
        }

        return lowerName.Contains("usb") ||
               normalizedName.Contains("usb") ||
               lowerName.Contains("udisk") ||
               lowerName.Contains("otg") ||
               lowerName.Contains("disk") ||
               System.Text.RegularExpressions.Regex.IsMatch(name, "^[0-9A-Fa-f]{4}-[0-9A-Fa-f]{4}$");
    }

    private void AddAndroidUsbRoot(List<string> roots, string root)
    {
        if (string.IsNullOrEmpty(root))
        {
            return;
        }

        if (IsAndroidInternalStorageRoot(root))
        {
            return;
        }

        try
        {
            string fullPath = Path.GetFullPath(root);
            #if UNITY_ANDROID && !UNITY_EDITOR
            if (!roots.Any(existing => string.Equals(existing, fullPath, StringComparison.OrdinalIgnoreCase)))
            {
                roots.Add(fullPath);
            }
            #else
            if (Directory.Exists(fullPath) && !roots.Any(existing => string.Equals(existing, fullPath, StringComparison.OrdinalIgnoreCase)))
            {
                roots.Add(fullPath);
            }
            #endif
        }
        catch
        {
            #if UNITY_ANDROID && !UNITY_EDITOR
            if (!roots.Contains(root))
            {
                roots.Add(root);
            }
            #else
            if (Directory.Exists(root) && !roots.Contains(root))
            {
                roots.Add(root);
            }
            #endif
        }
    }

    private bool IsAndroidInternalStorageRoot(string root)
    {
        if (string.IsNullOrEmpty(root))
        {
            return true;
        }

        string normalized = root.Replace('\\', '/').TrimEnd('/').ToLowerInvariant();
        return normalized == "/sdcard" ||
               normalized == "/storage/emulated" ||
               normalized.StartsWith("/storage/emulated/", StringComparison.OrdinalIgnoreCase) ||
               normalized == "/storage/self" ||
               normalized.StartsWith("/storage/self/", StringComparison.OrdinalIgnoreCase);
    }
    #endif
    
    #region BFI数据导出实现
    
    /// <summary>
    /// 导出BFI折线图为图片
    /// </summary>
    private bool ExportHistoryToImage(List<BFITestRecord> records, string exportPath)
    {
        try
        {
            // 这里需要图表生成库
            // 临时实现：生成数据点描述
            foreach (var record in records)
            {
                DateTime startTime = GetEffectiveStartTime(record);
                DateTime endTime = GetEffectiveEndTime(record, startTime);
                var validPoints = GetValidDataPoints(record);

                var imageDataBuilder = new StringBuilder();
                imageDataBuilder.AppendLine($"BFI折线图数据 - {record.TestName}");
                imageDataBuilder.AppendLine($"患者姓名: {GetPatientName(record)}");
                imageDataBuilder.AppendLine($"住院号: {GetPatientId(record)}");
                imageDataBuilder.AppendLine($"性别: {GetPatientGender(record)}");
                imageDataBuilder.AppendLine($"年龄: {FormatPatientAge(record.PatientAge)}");
                imageDataBuilder.AppendLine($"身高(cm): {FormatPatientHeight(record.PatientHeight)}");
                imageDataBuilder.AppendLine($"体重(kg): {FormatPatientWeight(record.PatientWeight)}");
                imageDataBuilder.AppendLine($"开始时间: {startTime:yyyy-MM-dd HH:mm:ss}");
                imageDataBuilder.AppendLine($"结束时间: {endTime:yyyy-MM-dd HH:mm:ss}");
                imageDataBuilder.AppendLine($"测试时长: {GetEffectiveDurationMinutes(startTime, endTime):F1} 分钟");
                imageDataBuilder.AppendLine($"有效数据点: {validPoints.Count}/{record?.DataPoints?.Count ?? 0}");
                imageDataBuilder.AppendLine("数据点:");
                
                foreach (var point in validPoints)
                {
                    imageDataBuilder.AppendLine($"  {FormatPointTime(point.Timestamp)} - BFI: {point.BFI:F2}");
                }
                
                string txtPath = exportPath + "_chart.txt";
                File.WriteAllText(txtPath, imageDataBuilder.ToString(), Encoding.UTF8);
                
                Debug.Log($"BFI图表数据已导出: {txtPath}");
            }
            return true;
        }
        catch (Exception ex)
        {
            Debug.LogError($"图表导出失败: {ex.Message}");
            return false;
        }
    }
    
    #endregion
    
    #region 历史记录导出
    
    /// <summary>
    /// 导出历史记录为TXT
    /// </summary>
    private bool ExportHistoryToTXT(List<BFITestRecord> records, string exportPath)
    {
        try
        {
            var reportBuilder = new StringBuilder();
            reportBuilder.AppendLine("BFI测试历史报告");
            reportBuilder.AppendLine($"生成时间: {DateTime.Now:yyyy-MM-dd HH:mm:ss}");
            reportBuilder.AppendLine($"记录数量: {records.Count}");
            reportBuilder.AppendLine();
            
            foreach (var record in records)
            {
                reportBuilder.AppendLine(GenerateBFIReportContent(record));
                reportBuilder.AppendLine("" + new string('=', 50));
            }
            
            string txtPath = GetUniqueFilePath(exportPath + "_history.txt");
            string content = reportBuilder.ToString();
            if (!WriteTextFileVerified(txtPath, content))
            {
                return false;
            }

            _lastExportedFilePath = txtPath;
            NotifyExportedFile(txtPath);
            Debug.Log($"历史记录报告已生成: {txtPath}");
            
            return true;
        }
        catch (Exception ex)
        {
            Debug.LogError($"历史记录TXT导出失败: {ex.Message}");
            return false;
        }
    }
    
    /// <summary>
    /// 导出历史记录为CSV
    /// </summary>
    private bool ExportHistoryToCSV(List<BFITestRecord> records, string exportPath)
    {
        try
        {
            var csvBuilder = new StringBuilder();
            csvBuilder.AppendLine("测试名称,患者姓名,住院号,性别,年龄,身高(cm),体重(kg),开始时间,结束时间,时间戳,BFI值,状态,备注");
            
            foreach (var record in records)
            {
                DateTime startTime = GetEffectiveStartTime(record);
                DateTime endTime = GetEffectiveEndTime(record, startTime);
                var validPoints = GetValidDataPoints(record);

                string patientName = EscapeCsv(GetPatientName(record));
                string patientId = EscapeCsv(GetPatientId(record));
                string patientGender = EscapeCsv(GetPatientGender(record));
                string patientAge = FormatPatientAge(record.PatientAge);
                string patientHeight = FormatPatientHeight(record.PatientHeight);
                string patientWeight = FormatPatientWeight(record.PatientWeight);

                if (validPoints.Count == 0)
                {
                    csvBuilder.AppendLine($"{EscapeCsv(record.TestName)},{patientName},{patientId},{patientGender},{patientAge},{patientHeight},{patientWeight},{startTime:yyyy-MM-dd HH:mm:ss},{endTime:yyyy-MM-dd HH:mm:ss},,,无有效数据点,");
                    continue;
                }

                foreach (var dataPoint in validPoints)
                {
                    csvBuilder.AppendLine($"{EscapeCsv(record.TestName)},{patientName},{patientId},{patientGender},{patientAge},{patientHeight},{patientWeight},{startTime:yyyy-MM-dd HH:mm:ss},{endTime:yyyy-MM-dd HH:mm:ss},{dataPoint.Timestamp:yyyy-MM-dd HH:mm:ss},{dataPoint.BFI:F2},{EscapeCsv(dataPoint.Status)},{EscapeCsv(dataPoint.Notes)}");
                }
            }
            
            string csvPath = GetUniqueFilePath(exportPath + "_history.csv");
            if (!WriteTextFileVerified(csvPath, csvBuilder.ToString()))
            {
                return false;
            }

            _lastExportedFilePath = csvPath;
            NotifyExportedFile(csvPath);
            
            Debug.Log($"历史记录CSV已导出: {csvPath}");
            return true;
        }
        catch (Exception ex)
        {
            Debug.LogError($"历史记录CSV导出失败: {ex.Message}");
            return false;
        }
    }

    /// <summary>
    /// 导出历史记录为PDF
    /// </summary>
    private bool ExportHistoryToPDF(List<BFITestRecord> records, string exportPath)
    {
        try
        {
            var lines = BuildPdfReportLines(records);
            string pdfPath = GetUniqueFilePath(exportPath + "_history.pdf");
            byte[] pdfBytes = BuildSimplePdfBytes(lines);
            if (!WriteBytesFileVerified(pdfPath, pdfBytes))
            {
                return false;
            }

            _lastExportedFilePath = pdfPath;
            NotifyExportedFile(pdfPath);

            Debug.Log($"历史记录PDF已导出: {pdfPath}");
            return true;
        }
        catch (Exception ex)
        {
            Debug.LogError($"历史记录PDF导出失败: {ex.Message}");
            return false;
        }
    }
    
    #endregion
    
    #region 辅助方法
    
    /// <summary>
    /// 生成BFI文件名
    /// </summary>
    private string GenerateBFIFilename(BFITestRecord record)
    {
        return $"BFI_{record.TestName}_{record.StartTime:yyyyMMdd_HHmmss}";
    }
    
    /// <summary>
    /// 获取导出路径
    /// </summary>
    private string GetExportPath(string filename)
    {
        string exportDirectory = EnsureExportDirectoryWithRootFolder(GetExportDirectory());
        if (!Directory.Exists(exportDirectory))
        {
            Directory.CreateDirectory(exportDirectory);
        }
        return Path.Combine(exportDirectory, filename);
    }

    private string GetUniqueFilePath(string filePath)
    {
        if (string.IsNullOrEmpty(filePath) || !File.Exists(filePath))
        {
            return filePath;
        }

        string directory = Path.GetDirectoryName(filePath);
        string fileName = Path.GetFileNameWithoutExtension(filePath);
        string extension = Path.GetExtension(filePath);

        for (int i = 1; i < 10000; i++)
        {
            string candidate = Path.Combine(directory, $"{fileName}_{i}{extension}");
            if (!File.Exists(candidate))
            {
                return candidate;
            }
        }

        return Path.Combine(directory, $"{fileName}_{Guid.NewGuid():N}{extension}");
    }
    
    /// <summary>
    /// 生成BFI报告内容
    /// </summary>
    private string GenerateBFIReportContent(BFITestRecord record)
    {
        var builder = new StringBuilder();
        DateTime startTime = GetEffectiveStartTime(record);
        DateTime endTime = GetEffectiveEndTime(record, startTime);
        var validPoints = GetValidDataPoints(record);
        int totalPoints = record?.DataPoints?.Count ?? 0;
        int ignoredPoints = totalPoints - validPoints.Count;
        
        builder.AppendLine($"BFI测试报告 - {record.TestName}");
        builder.AppendLine($"患者姓名: {GetPatientName(record)}");
        builder.AppendLine($"住院号: {GetPatientId(record)}");
        builder.AppendLine($"性别: {GetPatientGender(record)}");
        builder.AppendLine($"年龄: {FormatPatientAge(record.PatientAge)}");
        builder.AppendLine($"身高(cm): {FormatPatientHeight(record.PatientHeight)}");
        builder.AppendLine($"体重(kg): {FormatPatientWeight(record.PatientWeight)}");
        builder.AppendLine($"开始时间: {startTime:yyyy-MM-dd HH:mm:ss}");
        builder.AppendLine($"结束时间: {endTime:yyyy-MM-dd HH:mm:ss}");
        builder.AppendLine($"测试时长: {GetEffectiveDurationMinutes(startTime, endTime):F1} 分钟");
        builder.AppendLine($"数据点数量: {totalPoints}（有效: {validPoints.Count}）");

        if (record.EndTime <= DateTime.MinValue || record.EndTime < startTime)
        {
            builder.AppendLine("说明: 结束时间未正常记录，已按最后有效数据点时间进行估算。");
        }

        if (ignoredPoints > 0)
        {
            builder.AppendLine($"说明: 已过滤 {ignoredPoints} 条异常BFI数据点（超范围或非数值）。");
        }

        builder.AppendLine();
        
        if (validPoints.Count > 0)
        {
            builder.AppendLine("BFI数据统计:");
            var bfiValues = validPoints.ConvertAll(dp => dp.BFI);
            builder.AppendLine($"  最大值: {bfiValues.Max():F2}");
            builder.AppendLine($"  最小值: {bfiValues.Min():F2}");
            builder.AppendLine($"  平均值: {bfiValues.Average():F2}");
            builder.AppendLine();
            
            builder.AppendLine("详细数据:");
            foreach (var point in validPoints)
            {
                builder.AppendLine($"  {FormatPointTime(point.Timestamp)} | BFI: {point.BFI:F2} | 状态: {point.Status}");
            }
        }
        else
        {
            builder.AppendLine("无有效BFI数据点");
        }
        
        return builder.ToString();
    }

    private bool IsValidBfiValue(float value)
    {
        return !float.IsNaN(value) && !float.IsInfinity(value) && value >= 0f && value <= 1000f;
    }

    private List<BFIDataPoint> GetValidDataPoints(BFITestRecord record)
    {
        var validPoints = new List<BFIDataPoint>();
        if (record?.DataPoints == null)
        {
            return validPoints;
        }

        foreach (var point in record.DataPoints)
        {
            if (point == null || !IsValidBfiValue(point.BFI))
            {
                continue;
            }

            validPoints.Add(point);
        }

        return validPoints;
    }

    private string GetRecordDisplayName(BFITestRecord record)
    {
        if (!string.IsNullOrEmpty(record?.TestName))
        {
            return record.TestName;
        }

        if (!string.IsNullOrEmpty(record?.TestId))
        {
            return record.TestId;
        }

        return "未知记录";
    }

    private DateTime GetEffectiveStartTime(BFITestRecord record)
    {
        if (record.StartTime > DateTime.MinValue)
        {
            return record.StartTime;
        }

        if (record?.DataPoints != null)
        {
            foreach (var point in record.DataPoints)
            {
                if (point != null && point.Timestamp > DateTime.MinValue)
                {
                    return point.Timestamp;
                }
            }
        }

        return DateTime.Now;
    }

    private DateTime GetEffectiveEndTime(BFITestRecord record, DateTime startTime)
    {
        if (record.EndTime > startTime)
        {
            return record.EndTime;
        }

        DateTime lastPointTime = DateTime.MinValue;
        if (record?.DataPoints != null)
        {
            foreach (var point in record.DataPoints)
            {
                if (point != null && point.Timestamp > lastPointTime)
                {
                    lastPointTime = point.Timestamp;
                }
            }
        }

        if (lastPointTime > startTime)
        {
            return lastPointTime;
        }

        return startTime;
    }

    private double GetEffectiveDurationMinutes(DateTime startTime, DateTime endTime)
    {
        double duration = (endTime - startTime).TotalMinutes;
        return duration < 0 ? 0 : duration;
    }

    private string FormatPointTime(DateTime timestamp)
    {
        return timestamp > DateTime.MinValue ? timestamp.ToString("HH:mm:ss") : "--:--:--";
    }

    private string GetPatientName(BFITestRecord record)
    {
        return string.IsNullOrWhiteSpace(record?.PatientName) ? "未知患者" : record.PatientName;
    }

    private string GetPatientId(BFITestRecord record)
    {
        return string.IsNullOrWhiteSpace(record?.PatientId) ? "-" : record.PatientId;
    }

    private string GetPatientGender(BFITestRecord record)
    {
        return string.IsNullOrWhiteSpace(record?.PatientGender) ? "-" : record.PatientGender;
    }

    private string FormatPatientAge(int age)
    {
        return age > 0 ? age.ToString() : "-";
    }

    private string FormatPatientHeight(float height)
    {
        return height > 0f ? height.ToString("F1") : "-";
    }

    private string FormatPatientWeight(float weight)
    {
        return weight > 0f ? weight.ToString("F1") : "-";
    }

    private string EscapeCsv(string value)
    {
        if (string.IsNullOrEmpty(value))
        {
            return string.Empty;
        }

        string escaped = value.Replace("\"", "\"\"");
        if (escaped.Contains(",") || escaped.Contains("\n") || escaped.Contains("\r") || escaped.Contains("\""))
        {
            return $"\"{escaped}\"";
        }

        return escaped;
    }

    private List<string> BuildPdfReportLines(List<BFITestRecord> records)
    {
        var lines = new List<string>
        {
            "BFI测试历史报告",
            $"生成时间: {DateTime.Now:yyyy-MM-dd HH:mm:ss}",
            $"记录数量: {records.Count}",
            string.Empty
        };

        foreach (var record in records)
        {
            DateTime startTime = GetEffectiveStartTime(record);
            DateTime endTime = GetEffectiveEndTime(record, startTime);
            var validPoints = GetValidDataPoints(record);
            int totalPoints = record?.DataPoints?.Count ?? 0;

            lines.Add($"测试名称: {record.TestName}");
            lines.Add($"患者姓名: {GetPatientName(record)}    住院号: {GetPatientId(record)}");
            lines.Add($"性别: {GetPatientGender(record)}    年龄: {FormatPatientAge(record.PatientAge)}    身高(cm): {FormatPatientHeight(record.PatientHeight)}    体重(kg): {FormatPatientWeight(record.PatientWeight)}");
            lines.Add($"开始时间: {startTime:yyyy-MM-dd HH:mm:ss}");
            lines.Add($"结束时间: {endTime:yyyy-MM-dd HH:mm:ss}");
            lines.Add($"测试时长: {GetEffectiveDurationMinutes(startTime, endTime):F1} 分钟    数据点: {totalPoints}（有效: {validPoints.Count}）");

            if (validPoints.Count > 0)
            {
                var bfiValues = validPoints.ConvertAll(dp => dp.BFI);
                lines.Add($"统计: 最大值 {bfiValues.Max():F2}    最小值 {bfiValues.Min():F2}    平均值 {bfiValues.Average():F2}");
                lines.Add("详细数据（时间 / BFI / 状态）:");

                foreach (var point in validPoints.Take(120))
                {
                    lines.Add($"  {FormatPointTime(point.Timestamp)}    {point.BFI:F2}    {point.Status}");
                }

                if (validPoints.Count > 120)
                {
                    lines.Add($"  …… 其余 {validPoints.Count - 120} 个数据点请导出CSV查看。");
                }
            }
            else
            {
                lines.Add("无有效BFI数据点");
            }

            lines.Add(new string('-', 48));
            lines.Add(string.Empty);
        }

        return lines;
    }

    private void WriteSimplePdf(string filePath, List<string> lines)
    {
        if (!WriteBytesFileVerified(filePath, BuildSimplePdfBytes(lines)))
        {
            throw new IOException(_lastErrorMessage ?? "PDF文件写入失败");
        }
    }

    private bool WriteTextFileVerified(string filePath, string content)
    {
        byte[] bytes = Encoding.UTF8.GetBytes(content ?? string.Empty);
        return WriteBytesFileVerified(filePath, bytes);
    }

    private bool WriteBytesFileVerified(string filePath, byte[] bytes)
    {
        try
        {
            if (string.IsNullOrEmpty(filePath))
            {
                SetLastError("导出路径为空");
                return false;
            }

            bytes = bytes ?? new byte[0];
            string directory = Path.GetDirectoryName(filePath);
            if (!string.IsNullOrEmpty(directory) && !Directory.Exists(directory))
            {
                Directory.CreateDirectory(directory);
            }

            using (var stream = new FileStream(filePath, FileMode.Create, FileAccess.Write, FileShare.Read, 8192))
            {
                stream.Write(bytes, 0, bytes.Length);
                FlushFileStream(stream);
            }

            var info = new FileInfo(filePath);
            if (!info.Exists || info.Length < bytes.Length)
            {
                SetLastError($"导出文件写入不完整: {filePath}, 已写入 {info.Length} / {bytes.Length} 字节");
                return false;
            }

            return true;
        }
        catch (Exception ex)
        {
            SetLastError($"写入导出文件失败: {filePath}, {ex.Message}");
            return false;
        }
    }

    private void FlushFileStream(FileStream stream)
    {
        try
        {
            stream.Flush(true);
        }
        catch
        {
            stream.Flush();
        }
    }

    private byte[] BuildSimplePdfBytes(List<string> lines)
    {
        const float pageWidth = 595f;
        const float pageHeight = 842f;
        const float marginLeft = 48f;
        const float marginTop = 54f;
        const float lineHeight = 17f;
        const int maxCharsPerLine = 46;

        var wrappedLines = new List<string>();
        foreach (var line in lines)
        {
            wrappedLines.AddRange(WrapTextForPdf(line, maxCharsPerLine));
        }

        int linesPerPage = Mathf.Max(1, Mathf.FloorToInt((pageHeight - marginTop - 48f) / lineHeight));
        var pages = new List<List<string>>();
        for (int i = 0; i < wrappedLines.Count; i += linesPerPage)
        {
            pages.Add(wrappedLines.Skip(i).Take(linesPerPage).ToList());
        }

        if (pages.Count == 0)
        {
            pages.Add(new List<string> { "无可导出内容" });
        }

        var objects = new List<byte[]>();
        objects.Add(PdfAscii("<< /Type /Catalog /Pages 2 0 R >>"));

        var kids = new StringBuilder();
        for (int i = 0; i < pages.Count; i++)
        {
            int pageObjectNumber = 5 + i * 2;
            kids.Append($"{pageObjectNumber} 0 R ");
        }
        objects.Add(PdfAscii($"<< /Type /Pages /Kids [{kids}] /Count {pages.Count} >>"));

        objects.Add(PdfAscii("<< /Type /Font /Subtype /Type0 /BaseFont /STSong-Light /Encoding /UniGB-UCS2-H /DescendantFonts [4 0 R] >>"));
        objects.Add(PdfAscii("<< /Type /Font /Subtype /CIDFontType0 /BaseFont /STSong-Light /CIDSystemInfo << /Registry (Adobe) /Ordering (GB1) /Supplement 2 >> >>"));

        for (int i = 0; i < pages.Count; i++)
        {
            int pageObjectNumber = 5 + i * 2;
            int contentObjectNumber = pageObjectNumber + 1;
            objects.Add(PdfAscii($"<< /Type /Page /Parent 2 0 R /MediaBox [0 0 {pageWidth.ToString(CultureInfo.InvariantCulture)} {pageHeight.ToString(CultureInfo.InvariantCulture)}] /Resources << /Font << /F1 3 0 R >> >> /Contents {contentObjectNumber} 0 R >>"));

            byte[] content = BuildPdfPageContent(pages[i], pageHeight, marginLeft, marginTop, lineHeight);
            objects.Add(PdfStream(content));
        }

        using (var stream = new MemoryStream())
        {
            WriteAscii(stream, "%PDF-1.4\n%\u00e2\u00e3\u00cf\u00d3\n");
            var offsets = new List<long> { 0 };

            for (int i = 0; i < objects.Count; i++)
            {
                offsets.Add(stream.Position);
                WriteAscii(stream, $"{i + 1} 0 obj\n");
                stream.Write(objects[i], 0, objects[i].Length);
                WriteAscii(stream, "\nendobj\n");
            }

            long xrefOffset = stream.Position;
            WriteAscii(stream, $"xref\n0 {objects.Count + 1}\n");
            WriteAscii(stream, "0000000000 65535 f \n");
            for (int i = 1; i < offsets.Count; i++)
            {
                WriteAscii(stream, $"{offsets[i]:D10} 00000 n \n");
            }
            WriteAscii(stream, $"trailer\n<< /Size {objects.Count + 1} /Root 1 0 R >>\nstartxref\n{xrefOffset}\n%%EOF");
            return stream.ToArray();
        }
    }

    private IEnumerable<string> WrapTextForPdf(string text, int maxChars)
    {
        if (string.IsNullOrEmpty(text))
        {
            yield return string.Empty;
            yield break;
        }

        for (int index = 0; index < text.Length; index += maxChars)
        {
            int length = Math.Min(maxChars, text.Length - index);
            yield return text.Substring(index, length);
        }
    }

    private byte[] BuildPdfPageContent(List<string> lines, float pageHeight, float marginLeft, float marginTop, float lineHeight)
    {
        var builder = new StringBuilder();
        builder.AppendLine("BT");
        builder.AppendLine("/F1 11 Tf");
        builder.AppendLine($"{marginLeft.ToString(CultureInfo.InvariantCulture)} {(pageHeight - marginTop).ToString(CultureInfo.InvariantCulture)} Td");

        bool firstLine = true;
        foreach (var line in lines)
        {
            if (!firstLine)
            {
                builder.AppendLine($"0 -{lineHeight.ToString(CultureInfo.InvariantCulture)} Td");
            }
            builder.AppendLine($"{PdfUnicodeHexString(line)} Tj");
            firstLine = false;
        }

        builder.AppendLine("ET");
        return Encoding.ASCII.GetBytes(builder.ToString());
    }

    private string PdfUnicodeHexString(string value)
    {
        byte[] bytes = Encoding.BigEndianUnicode.GetBytes(value ?? string.Empty);
        var builder = new StringBuilder(bytes.Length * 2 + 2);
        builder.Append('<');
        foreach (byte b in bytes)
        {
            builder.Append(b.ToString("X2"));
        }
        builder.Append('>');
        return builder.ToString();
    }

    private byte[] PdfStream(byte[] content)
    {
        using (var memory = new MemoryStream())
        {
            WriteAscii(memory, $"<< /Length {content.Length} >>\nstream\n");
            memory.Write(content, 0, content.Length);
            WriteAscii(memory, "\nendstream");
            return memory.ToArray();
        }
    }

    private byte[] PdfAscii(string value)
    {
        return Encoding.ASCII.GetBytes(value);
    }

    private void WriteAscii(Stream stream, string value)
    {
        byte[] bytes = Encoding.ASCII.GetBytes(value);
        stream.Write(bytes, 0, bytes.Length);
    }

    /// <summary>
    /// 规范化导出目录，保证最终目录以 DCX_Export 结尾
    /// </summary>
    private string EnsureExportDirectoryWithRootFolder(string baseDirectory)
    {
        if (string.IsNullOrEmpty(baseDirectory))
        {
            return Path.Combine(Application.persistentDataPath, EXPORT_FOLDER);
        }

        string normalizedPath = baseDirectory.TrimEnd(Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar);
        string folderName = Path.GetFileName(normalizedPath);

        if (string.Equals(folderName, EXPORT_FOLDER, StringComparison.OrdinalIgnoreCase))
        {
            return normalizedPath;
        }

        return Path.Combine(normalizedPath, EXPORT_FOLDER);
    }

    private bool IsWritableDirectory(string directory)
    {
        try
        {
            if (string.IsNullOrEmpty(directory))
            {
                return false;
            }

            if (!Directory.Exists(directory))
            {
                Directory.CreateDirectory(directory);
            }

            string testFile = Path.Combine(directory, ".dcx_write_test");
            File.WriteAllText(testFile, DateTime.Now.ToString("O"), Encoding.UTF8);
            File.Delete(testFile);

#if !UNITY_ANDROID || UNITY_EDITOR
            if (!HasEnoughFreeSpace(directory, 10L * 1024L * 1024L))
            {
                return false;
            }
#endif

            return true;
        }
        catch (Exception ex)
        {
            Debug.LogWarning($"目录不可写: {directory}, {ex.Message}");
            return false;
        }
    }

    private bool HasEnoughFreeSpace(string directory, long requiredBytes)
    {
        try
        {
            string root = Path.GetPathRoot(Path.GetFullPath(directory));
            if (string.IsNullOrEmpty(root))
            {
                return true;
            }

            var drive = new DriveInfo(root);
            if (!drive.IsReady)
            {
                return true;
            }

            if (drive.AvailableFreeSpace < requiredBytes)
            {
                Debug.LogWarning($"导出目录空间不足: {directory}, 剩余 {drive.AvailableFreeSpace / 1024 / 1024}MB");
                return false;
            }

            return true;
        }
        catch (Exception ex)
        {
            Debug.LogWarning($"检查导出目录剩余空间失败: {directory}, {ex.Message}");
            return true;
        }
    }

    private void NotifyExportedFile(string filePath)
    {
        #if UNITY_ANDROID && !UNITY_EDITOR
        try
        {
            using (var unityClass = new AndroidJavaClass("com.unity3d.player.UnityPlayer"))
            using (var currentActivity = unityClass.GetStatic<AndroidJavaObject>("currentActivity"))
            {
                NotifyMediaScanner(currentActivity, filePath);
            }
        }
        catch (Exception ex)
        {
            Debug.LogWarning($"导出文件媒体扫描通知失败: {ex.Message}");
        }
        #endif
    }
    
    #endregion
    
    #region IDataExportService接口实现
    
    /// <summary>
    /// 检查是否可以导出
    /// </summary>
    public bool CanExport()
    {
        #if UNITY_ANDROID && !UNITY_EDITOR
        int sdkInt = GetAndroidSdkInt();
        if (sdkInt >= 29)
        {
            if (HasAndroidSafUsbDirectoryPermission())
            {
                return true;
            }

            return !string.IsNullOrEmpty(GetAndroidUsbExportDirectory(requireWritable: true));
        }

        if (!HasAndroidUsbWritePermission(sdkInt))
        {
            return false;
        }

        return !string.IsNullOrEmpty(GetAndroidUsbExportDirectory(requireWritable: true));
        #elif UNITY_STANDALONE_WIN || UNITY_EDITOR_WIN
        string exportDir = EnsureExportDirectoryWithRootFolder(GetExportDirectory());
        return IsWritableDirectory(exportDir);
        #else
        return true; // 编辑器模式总是可以导出
        #endif
    }
    
    /// <summary>
    /// 获取导出目录
    /// </summary>
    public string GetExportDirectory()
    {
        #if UNITY_ANDROID && !UNITY_EDITOR
        if (GetAndroidSdkInt() >= 29)
        {
            string directUsbDirectory = GetAndroidUsbExportDirectory(requireWritable: true);
            if (!string.IsNullOrEmpty(directUsbDirectory))
            {
                return directUsbDirectory;
            }

            return HasAndroidSafUsbDirectoryPermission() ? "U S B/DCX_Export" : null;
        }

        return GetAndroidUsbExportDirectory(requireWritable: true);
        #elif UNITY_STANDALONE_WIN || UNITY_EDITOR_WIN
        var usbDrives = GetUsbDrives();
        if (usbDrives.Count > 0)
        {
            return Path.Combine(usbDrives[0], EXPORT_FOLDER);
        }
        else
        {
            string desktopPath = Environment.GetFolderPath(Environment.SpecialFolder.Desktop);
            return Path.Combine(desktopPath, EXPORT_FOLDER);
        }
        #else
        return Path.Combine(Application.dataPath, "..", "Exports");
        #endif
    }

    public string GetLastExportedFilePath()
    {
        return _lastExportedFilePath;
    }
    
    /// <summary>
    /// 检查导出权限
    /// </summary>
    public bool CheckExportPermissions()
    {
        try
        {
            #if UNITY_ANDROID && !UNITY_EDITOR
            int sdkInt = GetAndroidSdkInt();

            if (sdkInt >= 29)
            {
                if (HasAndroidSafUsbDirectoryPermission())
                {
                    return true;
                }

                string androidScopedWritableUsbDirectory = GetAndroidUsbExportDirectory(requireWritable: true);
                if (!string.IsNullOrEmpty(androidScopedWritableUsbDirectory))
                {
                    return true;
                }

                string androidScopedDetectedUsbDirectory = GetAndroidUsbExportDirectory(requireWritable: false);
                if (!string.IsNullOrEmpty(androidScopedDetectedUsbDirectory))
                {
                    if (RequestAndroidSafUsbDirectoryPermission())
                    {
                        SetLastError($"检测到U盘路径 {androidScopedDetectedUsbDirectory}，但系统不允许直接写入。请在弹出的文件选择器中选择 U S B 根目录并授权，然后重新点击导出");
                    }
                }
                else if (RequestAndroidSafUsbDirectoryPermission())
                {
                    SetLastError("未检测到可直接写入的U盘路径。请在弹出的文件选择器中选择 U S B 根目录并授权，然后重新点击导出");
                }
                return false;
            }

            if (!HasAndroidUsbWritePermission(sdkInt))
            {
                RequestAndroidUsbPermission(sdkInt);
                return false;
            }

            string writableUsbDirectory = GetAndroidUsbExportDirectory(requireWritable: true);
            if (!string.IsNullOrEmpty(writableUsbDirectory))
            {
                return true;
            }

            string detectedUsbDirectory = GetAndroidUsbExportDirectory(requireWritable: false);
            if (!string.IsNullOrEmpty(detectedUsbDirectory))
            {
                SetLastError($"检测到U盘但无法写入: {detectedUsbDirectory}。请检查U盘格式、只读状态或系统存储权限");
            }
            else
            {
                SetLastError("未检测到可写入的U盘，请确认U盘已插入并重新导出");
            }

            return false;

        #elif UNITY_STANDALONE_WIN || UNITY_EDITOR_WIN
            
            string exportDir = GetExportDirectory();
            string finalExportDir = EnsureExportDirectoryWithRootFolder(exportDir);
            if (!IsWritableDirectory(finalExportDir))
            {
                Debug.LogWarning($"导出目录不可访问: {finalExportDir}");
                return false;
            }
            return true;
            #endif
        }
        catch (Exception ex)
        {
            Debug.LogError($"权限检查失败: {ex.Message}");
            return false;
        }
    }

    private bool HasAndroidUsbWritePermission()
    {
        #if UNITY_ANDROID && !UNITY_EDITOR
        return HasAndroidUsbWritePermission(new AndroidJavaClass("android.os.Build$VERSION").GetStatic<int>("SDK_INT"));
        #else
        return true;
        #endif
    }

    private bool HasAndroidUsbWritePermission(int sdkInt)
    {
        if (sdkInt <= 28)
        {
            return AndroidExportPermissionManager.HasWriteExternalStoragePermission();
        }

        return AndroidExportPermissionManager.HasManageExternalStoragePermission();
    }

    private void RequestAndroidUsbPermission(int sdkInt)
    {
        if (sdkInt <= 28)
        {
            SetLastError("缺少存储权限，已请求授权，请允许后重新导出");
            AndroidExportPermissionManager.RequestWriteExternalStoragePermission();
        }
        else
        {
            SetLastError("缺少所有文件访问权限，已打开权限设置，请授权后重新导出");
            AndroidExportPermissionManager.RequestManageExternalStoragePermission();
        }
    }
    
    #endregion
}

/// <summary>
/// 导出格式枚举
/// </summary>
public enum ExportFormat
{
    TXT,    // TXT报告
    CSV,    // CSV数据
    PDF,    // PDF报告
}