using System;
using System.Collections;
using System.Drawing;
using System.Drawing.Imaging;

namespace AForge.Imaging;

public class DocumentSkewChecker
{
	private int stepsPerDegree;

	private int houghHeight;

	private double thetaStep;

	private double maxSkewToDetect;

	private double[] sinMap;

	private double[] cosMap;

	private bool needToInitialize = true;

	private short[,] houghMap;

	private short maxMapIntensity;

	private int localPeakRadius = 4;

	private ArrayList lines = new ArrayList();

	public int StepsPerDegree
	{
		get
		{
			return stepsPerDegree;
		}
		set
		{
			stepsPerDegree = System.Math.Max(1, System.Math.Min(10, value));
			needToInitialize = true;
		}
	}

	public double MaxSkewToDetect
	{
		get
		{
			return maxSkewToDetect;
		}
		set
		{
			maxSkewToDetect = System.Math.Max(0.0, System.Math.Min(45.0, value));
			needToInitialize = true;
		}
	}

	[Obsolete("The property is deprecated and setting it has not any effect. Use MaxSkewToDetect property instead.")]
	public double MinBeta
	{
		get
		{
			return 0.0 - maxSkewToDetect;
		}
		set
		{
		}
	}

	[Obsolete("The property is deprecated and setting it has not any effect. Use MaxSkewToDetect property instead.")]
	public double MaxBeta
	{
		get
		{
			return maxSkewToDetect;
		}
		set
		{
		}
	}

	public int LocalPeakRadius
	{
		get
		{
			return localPeakRadius;
		}
		set
		{
			localPeakRadius = System.Math.Max(1, System.Math.Min(10, value));
		}
	}

	public DocumentSkewChecker()
	{
		StepsPerDegree = 10;
		MaxSkewToDetect = 30.0;
	}

	public double GetSkewAngle(Bitmap image)
	{
		return GetSkewAngle(image, new Rectangle(0, 0, ((Image)image).Width, ((Image)image).Height));
	}

	public double GetSkewAngle(Bitmap image, Rectangle rect)
	{
		//IL_0001: Unknown result type (might be due to invalid IL or missing references)
		//IL_000b: Invalid comparison between Unknown and I4
		if ((int)((Image)image).PixelFormat != 198659)
		{
			throw new UnsupportedImageFormatException("Unsupported pixel format of the source image.");
		}
		BitmapData val = image.LockBits(new Rectangle(0, 0, ((Image)image).Width, ((Image)image).Height), (ImageLockMode)1, (PixelFormat)198659);
		try
		{
			return GetSkewAngle(new UnmanagedImage(val), rect);
		}
		finally
		{
			image.UnlockBits(val);
		}
	}

	public double GetSkewAngle(BitmapData imageData)
	{
		return GetSkewAngle(new UnmanagedImage(imageData), new Rectangle(0, 0, imageData.Width, imageData.Height));
	}

	public double GetSkewAngle(BitmapData imageData, Rectangle rect)
	{
		return GetSkewAngle(new UnmanagedImage(imageData), rect);
	}

	public double GetSkewAngle(UnmanagedImage image)
	{
		return GetSkewAngle(image, new Rectangle(0, 0, image.Width, image.Height));
	}

	public unsafe double GetSkewAngle(UnmanagedImage image, Rectangle rect)
	{
		//IL_0001: Unknown result type (might be due to invalid IL or missing references)
		//IL_000b: Invalid comparison between Unknown and I4
		if ((int)image.PixelFormat != 198659)
		{
			throw new UnsupportedImageFormatException("Unsupported pixel format of the source image.");
		}
		InitHoughMap();
		int width = image.Width;
		int height = image.Height;
		int num = width / 2;
		int num2 = height / 2;
		rect.Intersect(new Rectangle(0, 0, width, height));
		int num3 = -num + rect.Left;
		int num4 = -num2 + rect.Top;
		int num5 = width - num - (width - rect.Right);
		int num6 = height - num2 - (height - rect.Bottom) - 1;
		int num7 = image.Stride - rect.Width;
		int num8 = (int)System.Math.Sqrt(num * num + num2 * num2);
		int num9 = num8 * 2;
		houghMap = new short[houghHeight, num9];
		byte* ptr = (byte*)image.ImageData.ToPointer() + (nint)rect.Top * (nint)image.Stride + rect.Left;
		byte* ptr2 = ptr + image.Stride;
		for (int i = num4; i < num6; i++)
		{
			int num10 = num3;
			while (num10 < num5)
			{
				if (*ptr < 128 && *ptr2 >= 128)
				{
					for (int j = 0; j < houghHeight; j++)
					{
						int num11 = (int)(cosMap[j] * (double)num10 - sinMap[j] * (double)i) + num8;
						if (num11 >= 0 && num11 < num9)
						{
							houghMap[j, num11]++;
						}
					}
				}
				num10++;
				ptr++;
				ptr2++;
			}
			ptr += num7;
			ptr2 += num7;
		}
		maxMapIntensity = 0;
		for (int k = 0; k < houghHeight; k++)
		{
			for (int l = 0; l < num9; l++)
			{
				if (houghMap[k, l] > maxMapIntensity)
				{
					maxMapIntensity = houghMap[k, l];
				}
			}
		}
		CollectLines((short)(width / 10));
		HoughLine[] mostIntensiveLines = GetMostIntensiveLines(5);
		double num12 = 0.0;
		double num13 = 0.0;
		HoughLine[] array = mostIntensiveLines;
		foreach (HoughLine houghLine in array)
		{
			if (houghLine.RelativeIntensity > 0.5)
			{
				num12 += houghLine.Theta * houghLine.RelativeIntensity;
				num13 += houghLine.RelativeIntensity;
			}
		}
		if (mostIntensiveLines.Length > 0)
		{
			num12 /= num13;
		}
		return num12 - 90.0;
	}

	private HoughLine[] GetMostIntensiveLines(int count)
	{
		int num = System.Math.Min(count, lines.Count);
		HoughLine[] array = new HoughLine[num];
		lines.CopyTo(0, array, 0, num);
		return array;
	}

	private void CollectLines(short minLineIntensity)
	{
		int length = houghMap.GetLength(0);
		int length2 = houghMap.GetLength(1);
		int num = length2 >> 1;
		lines.Clear();
		for (int i = 0; i < length; i++)
		{
			for (int j = 0; j < length2; j++)
			{
				short num2 = houghMap[i, j];
				if (num2 < minLineIntensity)
				{
					continue;
				}
				bool flag = false;
				int k = i - localPeakRadius;
				for (int num3 = i + localPeakRadius; k < num3; k++)
				{
					if (k < 0)
					{
						continue;
					}
					if (k >= length || flag)
					{
						break;
					}
					int l = j - localPeakRadius;
					for (int num4 = j + localPeakRadius; l < num4; l++)
					{
						if (l >= 0)
						{
							if (l >= length2)
							{
								break;
							}
							if (houghMap[k, l] > num2)
							{
								flag = true;
								break;
							}
						}
					}
				}
				if (!flag)
				{
					lines.Add(new HoughLine(90.0 - maxSkewToDetect + (double)i / (double)stepsPerDegree, (short)(j - num), num2, (double)num2 / (double)maxMapIntensity));
				}
			}
		}
		lines.Sort();
	}

	private void InitHoughMap()
	{
		if (needToInitialize)
		{
			needToInitialize = false;
			houghHeight = (int)(2.0 * maxSkewToDetect * (double)stepsPerDegree);
			thetaStep = 2.0 * maxSkewToDetect * System.Math.PI / 180.0 / (double)houghHeight;
			sinMap = new double[houghHeight];
			cosMap = new double[houghHeight];
			double num = 90.0 - maxSkewToDetect;
			for (int i = 0; i < houghHeight; i++)
			{
				sinMap[i] = System.Math.Sin(num * System.Math.PI / 180.0 + (double)i * thetaStep);
				cosMap[i] = System.Math.Cos(num * System.Math.PI / 180.0 + (double)i * thetaStep);
			}
		}
	}
}