using System.Collections.Concurrent;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.IO;
using Azaion.Annotator.Extensions;
using Azaion.Common.Database;
using Azaion.Common.DTO;
using Azaion.Common.DTO.Config;
using Azaion.Common.DTO.Queue;
using Azaion.Common.Extensions;
using LinqToDB;
using LinqToDB.Data;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using Color = System.Drawing.Color;
using ParallelOptions = Azaion.Annotator.Extensions.ParallelOptions;
using Size = System.Windows.Size;

namespace Azaion.Common.Services;

public delegate void ThumbnailsUpdatedEventHandler(double thumbnailsPercentage);

public class GalleryService(
    IOptions<DirectoriesConfig> directoriesConfig,
    IOptions<ThumbnailConfig> thumbnailConfig,
    IOptions<AnnotationConfig> annotationConfig,
    ILogger<GalleryService> logger,
    IDbFactory dbFactory) : IGalleryService
{
    private readonly DirectoriesConfig _dirConfig = directoriesConfig.Value;
    private readonly ThumbnailConfig _thumbnailConfig = thumbnailConfig.Value;
    private readonly AnnotationConfig _annotationConfig = annotationConfig.Value;

    public event ThumbnailsUpdatedEventHandler? ThumbnailsUpdate;


    private readonly SemaphoreSlim _updateLock = new(1);

    public double ProcessedThumbnailsPercentage { get; set; }

    private DirectoryInfo? _thumbnailsDirectory;

    private DirectoryInfo ThumbnailsDirectory
    {
        get
        {
            if (_thumbnailsDirectory != null)
                return _thumbnailsDirectory;

            var dir = new DirectoryInfo(_dirConfig.ThumbnailsDirectory);
            if (!dir.Exists)
                Directory.CreateDirectory(_dirConfig.ThumbnailsDirectory);
            _thumbnailsDirectory = new DirectoryInfo(_dirConfig.ThumbnailsDirectory);
            return _thumbnailsDirectory;
        }
    }

    public async Task ClearThumbnails(CancellationToken cancellationToken = default)
    {
        foreach(var file in new DirectoryInfo(_dirConfig.ThumbnailsDirectory).GetFiles())
            file.Delete();
        await dbFactory.RunWrite(async db =>
        {
            await db.Detections.DeleteAsync(x => true, token: cancellationToken);
            await db.Annotations.DeleteAsync(x => true, token: cancellationToken);
        });
    }

    public async Task RefreshThumbnails()
    {
        await _updateLock.WaitAsync();
        var existingAnnotations = new ConcurrentDictionary<string, Annotation>(await dbFactory.Run(async db =>
            await db.Annotations.ToDictionaryAsync(x => x.Name)));
        var missedAnnotations = new ConcurrentDictionary<string, Annotation>();
        try
        {
            var prefixLen = Constants.THUMBNAIL_PREFIX.Length;

            var thumbnails = ThumbnailsDirectory.GetFiles()
                .Select(x => Path.GetFileNameWithoutExtension(x.Name)[..^prefixLen])
                .GroupBy(x => x)
                .Select(gr => gr.Key)
                .ToHashSet();

            var files = new DirectoryInfo(_dirConfig.ImagesDirectory).GetFiles();
            var imagesCount = files.Length;

            await ParallelExt.ForEachAsync(files, async (file, cancellationToken) =>
            {
                var fName = file.Name.ToFName();
                try
                {
                    var labelName = Path.Combine(_dirConfig.LabelsDirectory, $"{fName}.txt");
                    if (!File.Exists(labelName))
                    {
                        File.Delete(file.FullName);
                        logger.LogInformation($"No labels found for image {file.FullName}! Image deleted!");
                        await dbFactory.DeleteAnnotations([fName], cancellationToken);
                        return;
                    }

                    //Read labels file only when it needed
                    if (existingAnnotations.ContainsKey(fName) && thumbnails.Contains(fName))
                        return;

                    var detections = (await YoloLabel.ReadFromFile(labelName, cancellationToken)).Select(x => new Detection(fName, x)).ToList();

                    //get names and time
                    var fileName = Path.GetFileNameWithoutExtension(file.Name);
                    var strings = fileName.Split("_");
                    var timeStr = strings.LastOrDefault();

                    string originalMediaName;
                    TimeSpan time;

                    //For some reason, TimeSpan.ParseExact doesn't work on every platform.
                    if (!string.IsNullOrEmpty(timeStr) &&
                        timeStr.Length == 6 &&
                        int.TryParse(timeStr[..1], out var hours) &&
                        int.TryParse(timeStr[1..3], out var minutes) &&
                        int.TryParse(timeStr[3..5], out var seconds) &&
                        int.TryParse(timeStr[5..], out var milliseconds))
                    {
                        time = new TimeSpan(0, hours, minutes, seconds, milliseconds * 100);
                        originalMediaName = fileName[..^7];
                    }
                    else
                    {
                        originalMediaName = fileName;
                        time = TimeSpan.FromSeconds(0);
                    }

                    var annotation = new Annotation
                    {
                        Time = time,
                        OriginalMediaName = originalMediaName,
                        Name = fName,
                        ImageExtension = Path.GetExtension(file.Name),
                        Detections = detections,
                        CreatedDate = File.GetCreationTimeUtc(file.FullName),
                        Source = SourceEnum.Manual,
                        CreatedRole = RoleEnum.Validator,
                        CreatedEmail = Constants.ADMIN_EMAIL,
                        AnnotationStatus = AnnotationStatus.Validated
                    };

                    //Remove duplicates
                    if (!existingAnnotations.ContainsKey(fName))
                    {
                        if (missedAnnotations.ContainsKey(fName))
                            logger.LogInformation($"{fName} is already exists! Duplicate!");
                        else
                            missedAnnotations.TryAdd(fName, annotation);
                    }


                    if (!thumbnails.Contains(fName))
                        await CreateThumbnail(annotation, cancellationToken: cancellationToken);

                }
                catch (Exception e)
                {
                    logger.LogError(e, $"Failed to generate thumbnail for {file.Name}! Error: {e.Message}");
                }
            },
            new ParallelOptions
            {
                ProgressFn = async num =>
                {
                    logger.LogInformation($"Processed {num} item by Thread {Environment.CurrentManagedThreadId}");
                    ProcessedThumbnailsPercentage = imagesCount == 0 ? 0 : Math.Min(100, num * 100 / (double)imagesCount);
                    ThumbnailsUpdate?.Invoke(ProcessedThumbnailsPercentage);
                    await Task.CompletedTask;
                },
                CpuUtilPercent = 100,
                ProgressUpdateInterval = 200
            });
        }
        catch (Exception e)
        {
            logger.LogError(e, $"Failed to refresh thumbnails! Error: {e.Message}");
        }
        finally
        {
            var copyOptions = new BulkCopyOptions
            {
                MaxBatchSize = 50
            };

            //Db could be updated during the long files scraping
            existingAnnotations = new ConcurrentDictionary<string, Annotation>(await dbFactory.Run(async db =>
                await db.Annotations.ToDictionaryAsync(x => x.Name)));
            var insertedDuplicates = missedAnnotations.Where(x => existingAnnotations.ContainsKey(x.Key)).ToList();
            var annotationsToInsert = missedAnnotations
                .Where(a => !existingAnnotations.ContainsKey(a.Key))
                .Select(x => x.Value)
                .ToList();

            await dbFactory.RunWrite(async db =>
            {
                await db.BulkCopyAsync(copyOptions, annotationsToInsert);
                await db.BulkCopyAsync(copyOptions, annotationsToInsert.SelectMany(x => x.Detections));
            });
            _updateLock.Release();
        }
    }

    public async Task CreateThumbnail(Annotation annotation, Image? originalImage = null, CancellationToken cancellationToken = default)
    {
        try
        {
            var width = (int)_thumbnailConfig.Size.Width;
            var height = (int)_thumbnailConfig.Size.Height;

            originalImage ??= Image.FromStream(new MemoryStream(await File.ReadAllBytesAsync(annotation.ImagePath, cancellationToken)));

            var bitmap = new Bitmap(width, height);

            using var g = Graphics.FromImage(bitmap);
            g.CompositingQuality = CompositingQuality.HighSpeed;
            g.SmoothingMode = SmoothingMode.HighSpeed;
            g.InterpolationMode = InterpolationMode.Default;

            var size = new Size(originalImage.Width, originalImage.Height);

            var thumbWhRatio = width / (float)height;
            var border = _thumbnailConfig.Border;

            var frameX = 0.0;
            var frameY = 0.0;
            var frameHeight = size.Height;
            var frameWidth = size.Width;

            var labels = annotation.Detections
                .Select(x => new CanvasLabel(x, size))
                .ToList();
            if (annotation.Detections.Any())
            {
                var labelsMinX = labels.Min(x => x.X);
                var labelsMaxX = labels.Max(x => x.X + x.Width);

                var labelsMinY = labels.Min(x => x.Y);
                var labelsMaxY = labels.Max(x => x.Y + x.Height);

                var labelsHeight = labelsMaxY - labelsMinY + 2 * border;
                var labelsWidth = labelsMaxX - labelsMinX + 2 * border;

                if (labelsWidth / labelsHeight > thumbWhRatio)
                {
                    frameWidth = labelsWidth;
                    frameHeight = Math.Min(labelsWidth / thumbWhRatio, size.Height);
                    frameX = Math.Max(0, labelsMinX - border);
                    frameY = Math.Max(0, 0.5 * (labelsMinY + labelsMaxY - frameHeight) - border);
                }
                else
                {
                    frameHeight = labelsHeight;
                    frameWidth = Math.Min(labelsHeight * thumbWhRatio, size.Width);
                    frameY = Math.Max(0, labelsMinY - border);
                    frameX = Math.Max(0, 0.5 * (labelsMinX + labelsMaxX - frameWidth) - border);
                }
            }

            var scale = frameHeight / height;
            g.DrawImage(originalImage, new Rectangle(0, 0, width, height), new RectangleF((float)frameX, (float)frameY, (float)frameWidth, (float)frameHeight), GraphicsUnit.Pixel);

            foreach (var label in labels)
            {
                var color = _annotationConfig.DetectionClassesDict[label.ClassNumber].Color;
                var brush = new SolidBrush(Color.FromArgb(color.A, color.R, color.G, color.B));

                g.DrawRectangle(new Pen(brush, width: 3), (float)((label.X - frameX) / scale), (float)((label.Y - frameY) / scale), (float)(label.Width / scale), (float)(label.Height / scale));
            }

            bitmap.Save(annotation.ThumbPath, ImageFormat.Jpeg);
        }
        catch (Exception e)
        {
            logger.LogError(e, e.Message);
        }
    }
    public async Task CreateAnnotatedImage(Annotation annotation, Image? originalImage = null, CancellationToken token = default)
    {
        originalImage ??= Image.FromStream(new MemoryStream(await File.ReadAllBytesAsync(annotation.ImagePath, token)));

        using var g = Graphics.FromImage(originalImage);
        foreach (var detection in annotation.Detections)
        {
            var detClass = _annotationConfig.DetectionClassesDict[detection.ClassNumber];
            var color = detClass.Color;
            var brush = new SolidBrush(Color.FromArgb(color.A, color.R, color.G, color.B));
            var det = new CanvasLabel(detection, new Size(originalImage.Width, originalImage.Height));
            g.DrawRectangle(new Pen(brush, width: 3), (float)det.X, (float)det.Y, (float)det.Width, (float)det.Height);

            var label  = detection.Confidence >= 0.995 ? detClass.UIName : $"{detClass.UIName}: {detection.Confidence * 100:F0}%";
            g.DrawTextBox(label, new PointF((float)(det.X + det.Width / 2.0), (float)(det.Y - 24)), brush, Brushes.Black);
        }

        var imagePath = Path.Combine(_dirConfig.ResultsDirectory, $"{annotation.Name}{Constants.RESULT_PREFIX}.jpg");
        if (File.Exists(imagePath))
            ResilienceExt.WithRetry(() => File.Delete(imagePath));

        originalImage.Save(imagePath, ImageFormat.Jpeg);
    }
}

public interface IGalleryService
{
    event ThumbnailsUpdatedEventHandler? ThumbnailsUpdate;
    Task CreateThumbnail(Annotation annotation, Image? originalImage = null, CancellationToken cancellationToken = default);
    Task RefreshThumbnails();
    Task ClearThumbnails(CancellationToken cancellationToken = default);
    Task CreateAnnotatedImage(Annotation annotation, Image? originalImage = null, CancellationToken token = default);
}