using System.IO.Compression;
using WorkCameraExport.Models;
using WorkCameraExport.Services.Interfaces;

namespace WorkCameraExport.Services
{
    /// <summary>
    /// 导出服务实现 - 负责在客户端本地生成 Excel 和 ZIP 文件
    /// </summary>
    public class ExportService : IExportService
    {
        private readonly IApiService _apiService;
        private readonly IImageService _imageService;
        private readonly IConfigService _configService;
        private readonly ILogService? _logService;
        private readonly ExcelService _excelService;

        // 配置常量
        private const int DefaultPageSize = 50;
        private const int DefaultConcurrency = 5;
        private const int DefaultImageQuality = 50;

        public ExportService(
            IApiService apiService,
            IImageService imageService,
            IConfigService configService,
            ILogService? logService = null)
        {
            _apiService = apiService;
            _imageService = imageService;
            _configService = configService;
            _logService = logService;
            _excelService = new ExcelService(logService);
        }

        #region 工作记录导出

        /// <summary>
        /// 导出工作记录到 Excel（按查询条件导出全部）
        /// </summary>
        public async Task ExportWorkRecordsAsync(
            WorkRecordQueryDto query,
            string outputPath,
            IProgress<ExportProgress>? progress = null,
            CancellationToken cancellationToken = default)
        {
            var tempDir = CreateTempDirectory();
            try
            {
                _logService?.Info($"开始导出工作记录: {outputPath}");

                // 获取配置
                var config = _configService.LoadConfig();
                var concurrency = config?.ImageDownloadConcurrency ?? DefaultConcurrency;
                var imageQuality = config?.ImageCompressQuality ?? DefaultImageQuality;

                // 1. 分页获取所有数据
                var allRecords = await FetchAllRecordsAsync(query, progress, cancellationToken);
                if (allRecords.Count == 0)
                {
                    _logService?.Warn("没有找到符合条件的工作记录");
                    throw new InvalidOperationException("没有找到符合条件的工作记录");
                }

                // 2. 收集所有图片 URL
                var allImageUrls = allRecords
                    .SelectMany(r => r.Images)
                    .Where(url => !string.IsNullOrEmpty(url))
                    .Distinct()
                    .ToList();

                ReportProgress(progress, allRecords.Count, 0, allImageUrls.Count, 0, "正在下载图片...");

                // 3. 并发下载图片
                var imagePathMap = await DownloadImagesAsync(
                    allImageUrls, tempDir, concurrency, imageQuality,
                    downloaded => ReportProgress(progress, allRecords.Count, 0, allImageUrls.Count, downloaded, "正在下载图片..."),
                    cancellationToken);

                // 4. 构建导出数据
                var exportItems = BuildExportItems(allRecords, imagePathMap);

                ReportProgress(progress, allRecords.Count, allRecords.Count, allImageUrls.Count, allImageUrls.Count, "正在生成 Excel...");

                // 5. 生成 Excel
                await _excelService.ExportWorkRecordsToExcelAsync(exportItems, outputPath, cancellationToken);

                ReportProgress(progress, allRecords.Count, allRecords.Count, allImageUrls.Count, allImageUrls.Count, "导出完成");
                _logService?.Info($"工作记录导出完成: {allRecords.Count} 条记录, {allImageUrls.Count} 张图片");
            }
            finally
            {
                // 清理临时目录
                CleanupTempDirectory(tempDir);
            }
        }

        /// <summary>
        /// 导出指定 ID 的工作记录到 Excel
        /// </summary>
        public async Task ExportWorkRecordsByIdsAsync(
            List<int> ids,
            string outputPath,
            IProgress<ExportProgress>? progress = null,
            CancellationToken cancellationToken = default)
        {
            if (ids == null || ids.Count == 0)
            {
                throw new ArgumentException("请选择要导出的记录", nameof(ids));
            }

            var tempDir = CreateTempDirectory();
            try
            {
                _logService?.Info($"开始导出选中的工作记录: {ids.Count} 条");

                var config = _configService.LoadConfig();
                var concurrency = config?.ImageDownloadConcurrency ?? DefaultConcurrency;
                var imageQuality = config?.ImageCompressQuality ?? DefaultImageQuality;

                // 1. 逐个获取记录详情
                var allRecords = new List<WorkRecordExportDto>();
                for (int i = 0; i < ids.Count; i++)
                {
                    cancellationToken.ThrowIfCancellationRequested();
                    ReportProgress(progress, ids.Count, i, 0, 0, $"正在获取记录 {i + 1}/{ids.Count}...");

                    var result = await _apiService.GetWorkRecordAsync(ids[i]);
                    if (result.Success && result.Data != null)
                    {
                        allRecords.Add(ConvertToExportDto(result.Data));
                    }
                }

                if (allRecords.Count == 0)
                {
                    throw new InvalidOperationException("没有找到有效的工作记录");
                }

                // 2. 收集所有图片 URL
                var allImageUrls = allRecords
                    .SelectMany(r => r.Images)
                    .Where(url => !string.IsNullOrEmpty(url))
                    .Distinct()
                    .ToList();

                ReportProgress(progress, allRecords.Count, allRecords.Count, allImageUrls.Count, 0, "正在下载图片...");

                // 3. 并发下载图片
                var imagePathMap = await DownloadImagesAsync(
                    allImageUrls, tempDir, concurrency, imageQuality,
                    downloaded => ReportProgress(progress, allRecords.Count, allRecords.Count, allImageUrls.Count, downloaded, "正在下载图片..."),
                    cancellationToken);

                // 4. 构建导出数据
                var exportItems = BuildExportItems(allRecords, imagePathMap);

                ReportProgress(progress, allRecords.Count, allRecords.Count, allImageUrls.Count, allImageUrls.Count, "正在生成 Excel...");

                // 5. 生成 Excel
                await _excelService.ExportWorkRecordsToExcelAsync(exportItems, outputPath, cancellationToken);

                ReportProgress(progress, allRecords.Count, allRecords.Count, allImageUrls.Count, allImageUrls.Count, "导出完成");
                _logService?.Info($"选中记录导出完成: {allRecords.Count} 条记录");
            }
            finally
            {
                CleanupTempDirectory(tempDir);
            }
        }


        /// <summary>
        /// 分页获取所有记录
        /// </summary>
        private async Task<List<WorkRecordExportDto>> FetchAllRecordsAsync(
            WorkRecordQueryDto query,
            IProgress<ExportProgress>? progress,
            CancellationToken cancellationToken)
        {
            var allRecords = new List<WorkRecordExportDto>();
            var pageNum = 1;
            var pageSize = DefaultPageSize;
            int totalRecords = 0;

            do
            {
                cancellationToken.ThrowIfCancellationRequested();

                var pagedQuery = new WorkRecordQueryDto
                {
                    PageNum = pageNum,
                    PageSize = pageSize,
                    StartDate = query.StartDate,
                    EndDate = query.EndDate,
                    DeptName = query.DeptName,
                    Address = query.Address,
                    Content = query.Content,
                    WorkerName = query.WorkerName,
                    StatusName = query.StatusName
                };

                var result = await _apiService.GetWorkRecordsAsync(pagedQuery);
                if (!result.Success || result.Data == null)
                {
                    _logService?.Error($"获取工作记录失败: {result.Message}");
                    throw new Exception($"获取工作记录失败: {result.Message}");
                }

                if (pageNum == 1)
                {
                    totalRecords = result.Data.TotalNum;
                    ReportProgress(progress, totalRecords, 0, 0, 0, $"正在获取数据 (共 {totalRecords} 条)...");
                }

                // 转换为导出 DTO
                foreach (var record in result.Data.Result)
                {
                    allRecords.Add(ConvertToExportDto(record));
                }

                ReportProgress(progress, totalRecords, allRecords.Count, 0, 0, $"正在获取数据 {allRecords.Count}/{totalRecords}...");

                // 检查是否还有更多数据
                if (result.Data.Result.Count < pageSize || allRecords.Count >= totalRecords)
                {
                    break;
                }

                pageNum++;
            } while (true);

            return allRecords;
        }

        /// <summary>
        /// 下载图片并返回 URL 到本地路径的映射
        /// </summary>
        private async Task<Dictionary<string, string?>> DownloadImagesAsync(
            List<string> imageUrls,
            string outputDir,
            int concurrency,
            int quality,
            Action<int>? progressCallback,
            CancellationToken cancellationToken)
        {
            if (imageUrls.Count == 0)
            {
                return new Dictionary<string, string?>();
            }

            var downloadProgress = new Progress<int>(count => progressCallback?.Invoke(count));

            var results = await _imageService.DownloadImagesAsync(
                imageUrls,
                outputDir,
                concurrency,
                downloadProgress,
                cancellationToken);

            // 压缩下载的图片
            foreach (var kvp in results.Where(r => r.Value != null))
            {
                try
                {
                    var originalPath = kvp.Value!;
                    var imageData = await File.ReadAllBytesAsync(originalPath, cancellationToken);
                    var compressedData = _imageService.CompressAndResizeImage(imageData, 100, 60, quality);
                    await File.WriteAllBytesAsync(originalPath, compressedData, cancellationToken);
                }
                catch (Exception ex)
                {
                    _logService?.Warn($"压缩图片失败: {kvp.Key}, {ex.Message}");
                }
            }

            return results;
        }

        /// <summary>
        /// 构建导出项列表
        /// </summary>
        private List<WorkRecordExportItem> BuildExportItems(
            List<WorkRecordExportDto> records,
            Dictionary<string, string?> imagePathMap)
        {
            return records.Select(r =>
            {
                var item = WorkRecordExportItem.FromDto(r);
                item.ImagePaths = r.Images
                    .Where(url => !string.IsNullOrEmpty(url) && imagePathMap.ContainsKey(url))
                    .Select(url => imagePathMap[url])
                    .Where(path => path != null)
                    .Cast<string>()
                    .ToList();
                return item;
            }).ToList();
        }

        /// <summary>
        /// 转换 WorkRecordDto 为 WorkRecordExportDto
        /// </summary>
        private WorkRecordExportDto ConvertToExportDto(WorkRecordDto dto)
        {
            return new WorkRecordExportDto
            {
                Id = dto.Id,
                DeptName = dto.DeptName,
                RecordTime = dto.RecordTime,
                Longitude = dto.Longitude,
                Latitude = dto.Latitude,
                Address = dto.Address,
                Content = dto.Content,
                StatusName = dto.StatusName,
                Workers = dto.Workers?.Select(w => w.WorkerName).ToList() ?? new List<string>(),
                Images = dto.Images.Select(i => i.Url).ToList(),
                CreateTime = dto.CreateTime,
                UpdateTime = dto.UpdateTime
            };
        }

        #endregion

        #region 月报表导出

        /// <summary>
        /// 导出月报表到 Excel
        /// </summary>
        public async Task ExportMonthlyReportAsync(
            List<MonthlyReportDto> data,
            string outputPath)
        {
            if (data == null || data.Count == 0)
            {
                throw new ArgumentException("没有数据可导出", nameof(data));
            }

            _logService?.Info($"开始导出月报表: {data.Count} 条记录");
            await _excelService.ExportMonthlyReportToExcelAsync(data, outputPath);
            _logService?.Info($"月报表导出完成: {outputPath}");
        }

        #endregion


        #region 照片 ZIP 下载

        /// <summary>
        /// 下载指定月份的照片并打包成 ZIP
        /// </summary>
        public async Task DownloadPhotosZipAsync(
            string yearMonth,
            string outputPath,
            IProgress<DownloadProgress>? progress = null,
            CancellationToken cancellationToken = default)
        {
            if (string.IsNullOrEmpty(yearMonth))
            {
                throw new ArgumentException("请选择月份", nameof(yearMonth));
            }

            var tempDir = CreateTempDirectory();
            try
            {
                _logService?.Info($"开始下载 {yearMonth} 月份照片");

                var config = _configService.LoadConfig();
                var concurrency = config?.ImageDownloadConcurrency ?? DefaultConcurrency;

                // 1. 获取月份图片列表
                ReportDownloadProgress(progress, 0, 0, "正在获取图片列表...");
                var result = await _apiService.GetMonthImagesAsync(yearMonth);
                if (!result.Success || result.Data == null || result.Data.Count == 0)
                {
                    throw new InvalidOperationException($"没有找到 {yearMonth} 月份的图片");
                }

                var monthImages = result.Data;
                var totalImages = monthImages.Sum(m => m.ImageUrls.Count);
                ReportDownloadProgress(progress, totalImages, 0, $"共 {totalImages} 张图片");

                // 2. 按目录结构下载图片
                var downloadedCount = 0;
                foreach (var record in monthImages)
                {
                    cancellationToken.ThrowIfCancellationRequested();

                    // 创建目录结构
                    var directories = CreateDirectoryStructure(tempDir, yearMonth, record);

                    // 下载图片到各个目录
                    foreach (var imageUrl in record.ImageUrls)
                    {
                        cancellationToken.ThrowIfCancellationRequested();

                        var imageData = await _imageService.DownloadImageAsync(imageUrl, cancellationToken);
                        if (imageData != null)
                        {
                            var fileName = GetFileNameFromUrl(imageUrl);
                            
                            // 保存到各个分类目录
                            foreach (var dir in directories)
                            {
                                var filePath = Path.Combine(dir, fileName);
                                filePath = EnsureUniqueFilePath(filePath);
                                await File.WriteAllBytesAsync(filePath, imageData, cancellationToken);
                            }
                        }

                        downloadedCount++;
                        ReportDownloadProgress(progress, totalImages, downloadedCount, $"正在下载 {downloadedCount}/{totalImages}...");
                    }
                }

                // 3. 打包成 ZIP
                ReportDownloadProgress(progress, totalImages, downloadedCount, "正在打包 ZIP...");
                
                // 确保输出目录存在
                var outputDir = Path.GetDirectoryName(outputPath);
                if (!string.IsNullOrEmpty(outputDir) && !Directory.Exists(outputDir))
                {
                    Directory.CreateDirectory(outputDir);
                }

                // 删除已存在的文件
                if (File.Exists(outputPath))
                {
                    File.Delete(outputPath);
                }

                ZipFile.CreateFromDirectory(tempDir, outputPath, CompressionLevel.Optimal, false);

                ReportDownloadProgress(progress, totalImages, downloadedCount, "下载完成");
                _logService?.Info($"照片 ZIP 下载完成: {outputPath}, 共 {downloadedCount} 张图片");
            }
            finally
            {
                CleanupTempDirectory(tempDir);
            }
        }

        /// <summary>
        /// 创建目录结构并返回所有目录路径
        /// 目录结构：/workfiles/{yyyyMM}/{yyyyMMdd}/当日照片/、参与人员/{人员姓名}/、工作内容/{工作内容}/、部门/{部门名称}/
        /// </summary>
        private List<string> CreateDirectoryStructure(string baseDir, string yearMonth, MonthImageDto record)
        {
            var directories = new List<string>();
            var yyyyMM = yearMonth.Replace("-", "");
            var yyyyMMdd = record.RecordDate?.ToString("yyyyMMdd") ?? yyyyMM + "01";

            var basePath = Path.Combine(baseDir, "workfiles", yyyyMM, yyyyMMdd);

            // 1. 当日照片目录
            var dailyDir = Path.Combine(basePath, "当日照片");
            EnsureDirectoryExists(dailyDir);
            directories.Add(dailyDir);

            // 2. 参与人员目录
            foreach (var worker in record.Workers.Where(w => !string.IsNullOrEmpty(w)))
            {
                var workerDir = Path.Combine(basePath, "参与人员", SanitizeFileName(worker));
                EnsureDirectoryExists(workerDir);
                directories.Add(workerDir);
            }

            // 3. 工作内容目录
            if (!string.IsNullOrEmpty(record.Content))
            {
                var contentDir = Path.Combine(basePath, "工作内容", SanitizeFileName(record.Content));
                EnsureDirectoryExists(contentDir);
                directories.Add(contentDir);
            }

            // 4. 部门目录
            if (!string.IsNullOrEmpty(record.DeptName))
            {
                var deptDir = Path.Combine(basePath, "部门", SanitizeFileName(record.DeptName));
                EnsureDirectoryExists(deptDir);
                directories.Add(deptDir);
            }

            return directories;
        }

        #endregion

        #region 辅助方法

        /// <summary>
        /// 创建临时目录
        /// </summary>
        private string CreateTempDirectory()
        {
            var tempDir = Path.Combine(Path.GetTempPath(), "WorkCameraExport", $"export_{Guid.NewGuid():N}");
            Directory.CreateDirectory(tempDir);
            return tempDir;
        }

        /// <summary>
        /// 清理临时目录
        /// </summary>
        private void CleanupTempDirectory(string tempDir)
        {
            try
            {
                var config = _configService.LoadConfig();
                if (config?.AutoCleanTempFiles != false && Directory.Exists(tempDir))
                {
                    Directory.Delete(tempDir, true);
                    _logService?.Info($"已清理临时目录: {tempDir}");
                }
            }
            catch (Exception ex)
            {
                _logService?.Warn($"清理临时目录失败: {ex.Message}");
            }
        }

        /// <summary>
        /// 确保目录存在
        /// </summary>
        private void EnsureDirectoryExists(string path)
        {
            if (!Directory.Exists(path))
            {
                Directory.CreateDirectory(path);
            }
        }

        /// <summary>
        /// 从 URL 提取文件名
        /// </summary>
        private string GetFileNameFromUrl(string url)
        {
            try
            {
                var uri = new Uri(url);
                var fileName = Path.GetFileName(uri.LocalPath);
                if (!string.IsNullOrWhiteSpace(fileName) && fileName.Contains('.'))
                {
                    return SanitizeFileName(fileName);
                }
            }
            catch { }

            return $"{Guid.NewGuid():N}.jpg";
        }

        /// <summary>
        /// 清理文件名中的非法字符
        /// </summary>
        private string SanitizeFileName(string fileName)
        {
            var invalidChars = Path.GetInvalidFileNameChars();
            var sanitized = fileName;
            foreach (var c in invalidChars)
            {
                sanitized = sanitized.Replace(c, '_');
            }
            // 限制长度
            if (sanitized.Length > 50)
            {
                var ext = Path.GetExtension(sanitized);
                sanitized = sanitized.Substring(0, 50 - ext.Length) + ext;
            }
            return sanitized;
        }

        /// <summary>
        /// 确保文件路径唯一
        /// </summary>
        private string EnsureUniqueFilePath(string filePath)
        {
            if (!File.Exists(filePath))
            {
                return filePath;
            }

            var directory = Path.GetDirectoryName(filePath) ?? "";
            var fileNameWithoutExt = Path.GetFileNameWithoutExtension(filePath);
            var extension = Path.GetExtension(filePath);
            var counter = 1;

            string newPath;
            do
            {
                newPath = Path.Combine(directory, $"{fileNameWithoutExt}_{counter}{extension}");
                counter++;
            } while (File.Exists(newPath));

            return newPath;
        }

        /// <summary>
        /// 报告导出进度
        /// </summary>
        private void ReportProgress(
            IProgress<ExportProgress>? progress,
            int totalRecords,
            int processedRecords,
            int totalImages,
            int downloadedImages,
            string status)
        {
            progress?.Report(new ExportProgress
            {
                TotalRecords = totalRecords,
                ProcessedRecords = processedRecords,
                TotalImages = totalImages,
                DownloadedImages = downloadedImages,
                Status = status
            });
        }

        /// <summary>
        /// 报告下载进度
        /// </summary>
        private void ReportDownloadProgress(
            IProgress<DownloadProgress>? progress,
            int totalImages,
            int downloadedImages,
            string status)
        {
            progress?.Report(new DownloadProgress
            {
                TotalImages = totalImages,
                DownloadedImages = downloadedImages,
                Status = status
            });
        }

        #endregion
    }
}