using System;
using System.IO;
using System.Threading.Tasks;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using Prism.Events;
using XP.Common.Logging.Interfaces;
using XP.Hardware.Detector.Abstractions;
using XP.Hardware.Detector.Abstractions.Events;

namespace XP.Hardware.Detector.Services
{
    /// <summary>
    /// 图像服务实现 | Image service implementation
    /// 提供最新帧获取和 16 位 TIFF 保存功能
    /// </summary>
    public class ImageService : IImageService
    {
        private readonly IDetectorService _detectorService;
        private readonly ILoggerService _logger;

        /// <summary>
        /// 最新采集的原始图像数据 | Latest captured raw image data
        /// </summary>
        private volatile ImageCapturedEventArgs _latestFrame;

        public ImageService(
            IDetectorService detectorService,
            IEventAggregator eventAggregator,
            ILoggerService logger)
        {
            _detectorService = detectorService ?? throw new ArgumentNullException(nameof(detectorService));
            _logger = logger?.ForModule<ImageService>();

            // 订阅图像采集事件，缓存最新帧 | Subscribe to image captured event, cache latest frame
            if (eventAggregator == null) throw new ArgumentNullException(nameof(eventAggregator));
            eventAggregator.GetEvent<ImageCapturedEvent>()
                .Subscribe(OnImageCaptured, ThreadOption.BackgroundThread);
        }

        /// <inheritdoc/>
        public ImageCapturedEventArgs LatestFrame => _latestFrame;

        /// <summary>
        /// 图像采集事件回调，缓存最新帧 | Image captured callback, cache latest frame
        /// </summary>
        private void OnImageCaptured(ImageCapturedEventArgs args)
        {
            if (args?.ImageData != null && args.Width > 0 && args.Height > 0)
                _latestFrame = args;
        }

        /// <inheritdoc/>
        public Task<DetectorResult> SaveAsTiffAsync(ushort[] imageData, int width, int height, string filePath)
        {
            return Task.Run(() =>
            {
                try
                {
                    if (imageData == null || imageData.Length == 0)
                        return DetectorResult.Failure("图像数据为空 | Image data is empty");

                    if (width <= 0 || height <= 0)
                        return DetectorResult.Failure($"图像尺寸无效：{width}x{height} | Invalid image size: {width}x{height}");

                    // 确保目录存在 | Ensure directory exists
                    var directory = Path.GetDirectoryName(filePath);
                    if (!string.IsNullOrEmpty(directory))
                        Directory.CreateDirectory(directory);

                    // 创建 16 位灰度 BitmapSource | Create 16-bit grayscale BitmapSource
                    int stride = width * sizeof(ushort);
                    var bitmap = BitmapSource.Create(width, height, 96, 96, PixelFormats.Gray16, null, imageData, stride);
                    bitmap.Freeze();

                    // 编码为 TIFF（无压缩）| Encode as TIFF (no compression)
                    var encoder = new TiffBitmapEncoder { Compression = TiffCompressOption.None };
                    encoder.Frames.Add(BitmapFrame.Create(bitmap));

                    using (var stream = new FileStream(filePath, FileMode.Create, FileAccess.Write))
                    {
                        encoder.Save(stream);
                    }

                    _logger?.Info("图像已保存：{FilePath}，分辨率：{Width}x{Height} | Image saved: {FilePath}, resolution: {Width}x{Height}", filePath, width, height);
                    return DetectorResult.Success($"图像已保存 | Image saved: {filePath}");
                }
                catch (Exception ex)
                {
                    var errorMsg = $"保存图像失败：{ex.Message} | Failed to save image: {ex.Message}";
                    _logger?.Error(ex, errorMsg);
                    return DetectorResult.Failure(errorMsg, ex);
                }
            });
        }

        /// <inheritdoc/>
        public Task<DetectorResult> SaveAsTiffAsync(ushort[] imageData, int width, int height, string saveDirectory, string prefix, int frameNumber)
        {
            var timestamp = DateTime.Now.ToString("yyyyMMdd_HHmmss_fff");
            var fileName = $"{prefix}_{timestamp}_F{frameNumber}.tif";
            var filePath = Path.Combine(saveDirectory, fileName);
            return SaveAsTiffAsync(imageData, width, height, filePath);
        }

        /// <inheritdoc/>
        public Task<DetectorResult> SaveLatestFrameAsync(string saveDirectory, string prefix)
        {
            var frame = _latestFrame;
            if (frame?.ImageData == null)
                return Task.FromResult(DetectorResult.Failure("无可用的图像数据 | No image data available"));

            return SaveAsTiffAsync(frame.ImageData, (int)frame.Width, (int)frame.Height, saveDirectory, prefix, frame.FrameNumber);
        }

        /// <inheritdoc/>
        public string GetDefaultSaveDirectory()
        {
            var config = _detectorService.GetCurrentConfig();
            if (config != null && !string.IsNullOrEmpty(config.SavePath))
                return config.SavePath;

            return Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "Images");
        }
    }
}