using ImageMagick;
using Ocr.Tesseract;
using Ocr.Tesseract.Configuration;
using Ocr.Tesseract.Extensions;
using Ocr.Tesseract.Models;
using Ocr.Tesseract.Screenshots;
using Ocr.Tesseract.Screenshots.Configuration;
using Process.Abstract.Configuration;
using Process.Interface;
using System.Text.Json;
using System.Text.RegularExpressions;

namespace CLI.Processor;

internal class EvaluationProcessor
{
  #region Configuration

  /// <summary>
  /// <see cref="Regex"/> expression for extracting whole words from scan results
  /// </summary>
  private static readonly Regex wordRegex = new(
    @"[\w'\-]{2,}",
    RegexOptions.Compiled | RegexOptions.Multiline | RegexOptions.IgnoreCase
  );

  private static readonly ITesseractConfiguration tesseractConfig =
    new TesseractScreenshotConfiguration
    {
      DataPath = "tessdata",
      Languages = new[] { "eng", "deu" }
    };

  #endregion

  #region Processors

  private static readonly IProcessorChain<ScanResult, ScanResult> postProcessor =
    new ProcessorChainConfiguration<ScanResult, ScanResult>()
      .Use(new ConfidenceFilter(50))
      .Use(new ToLowerProcessor())
      .Use(new DuplicateFilter())
      .Complete(new RegexFilter(wordRegex));

  private static readonly TesseractProcessor tesseractProcessor = new(tesseractConfig);

  private readonly StopwatchProcessor<MagickImage, MagickImage> _thresholdProcessor;

  #endregion


  public string OutputFolder { get; init; } = "results";

  public EvaluationProcessor(
    IProcessor<MagickImage, MagickImage> thresholdProcessor
  ) => _thresholdProcessor = new StopwatchProcessor<MagickImage, MagickImage>(thresholdProcessor);

  /// <inheritdoc />
  public Task Process(MagickImage image) => Task.Run(async () =>
  {
    var words = MakeProcessor()
      .Process(new[] { image })
      .Select(r => r.Word)
      .ToArray();

    var result = new
    {
      Words = words.ToArray(),
      Elapsed = _thresholdProcessor.Elapsed?.TotalMilliseconds,
    };

    var name = Path.GetFileNameWithoutExtension(image.FileName);
    var path = Path.Combine(OutputFolder, $"{name}.{_thresholdProcessor}.json");
    await using var file = File.OpenWrite(path);
    await JsonSerializer.SerializeAsync(file, result);
  });

  private IProcessorChain<MagickImage, ScanResult> MakeProcessor()
  {
    var preprocessing = new ProcessorChainConfiguration<MagickImage, MagickImage>()
      .Use(new CloneImageProcessor())
      .Use(new ResizeProcessor(FilterType.Lanczos2Sharp, PixelInterpolateMethod.Mesh))
      .Use(new NormalizeProcessor())
      .Use(_thresholdProcessor)
      .Use(new AddBorderProcessor(10))
      .Use(new BinarizeProcessor())
      .Use(new NegateCloneProcessor())
      .Complete(OnPreprocessed);

    return new ProcessorChainConfiguration<MagickImage, ScanResult>()
      .Use(preprocessing)
      .Use(tesseractProcessor)
      .Complete(postProcessor);
  }

  private IEnumerable<MagickImage> OnPreprocessed(IEnumerable<MagickImage> images)
  {
    var tImages = images.ToArray();

    for (var i = 0; i < tImages.Length; i++)
    {
      var image = tImages[i].CloneImage();
      var name = Path.GetFileName(image.FileName);
      var path = Path.Combine(OutputFolder, $"{_thresholdProcessor}.{i:D2}.{name}");
      image.Write(path);
    }

    return tImages;
  }
}