using System;
using System.Diagnostics;
using System.Drawing;

namespace DesertPaintCodex.Util
{
    public class Pixels
    {
        private readonly Bitmap _bitmap;
        private readonly int _pixelMultiplier;

        public int Height => _bitmap.Height / _pixelMultiplier;
        public int Width => _bitmap.Width / _pixelMultiplier;

        public Pixels(Bitmap bitmap, int pixellMutliplier)
        {
            _bitmap = bitmap;
            _pixelMultiplier = pixellMutliplier;
        }

        public Color ColorAt(int x, int y)
        {
            return _bitmap.GetPixel(x * _pixelMultiplier, y * _pixelMultiplier);
        }

        public bool DoesPixelMatch(int x, int y, Func<Color, bool> matchFunc)
        {
            int xMult = x * _pixelMultiplier;
            int yMult = y * _pixelMultiplier;

            if (xMult < 0 || xMult >= _bitmap.Width || yMult < 0 || yMult >= _bitmap.Height)
            {
                Debug.WriteLine("Problem at position [" + x + ", " + y + "]");
            }
            
            return matchFunc(_bitmap.GetPixel(x * _pixelMultiplier, y * _pixelMultiplier));
        }

        // Compute length of horizontal bar starting at x,y using matching function
        public int LengthOfColorAt(int x, int y, int scanWidth, Func<Color, bool> matchFunc)
        {
            int count = 0;
            for (int xVal = x; xVal < scanWidth + x; ++xVal)
            {
                Color c = _bitmap.GetPixel(xVal * _pixelMultiplier, y * _pixelMultiplier);
                if (!matchFunc(c))
                {
                    break;
                }
                ++count;
            }
            return count;
        }

        public bool IsSolidPatchAt(int x, int y, int patchWidth, int patchHeight)
        {
            if ((x + patchWidth >= Width) || (y + patchHeight >= Height)) return false;
            Color color = _bitmap.GetPixel(x * _pixelMultiplier, y * _pixelMultiplier);
            
            // Debug.WriteLine("color at {0},{1} = {2},{3},{4}", x, y, color.R, color.G, color.B);

            for (int pX = 0; pX < patchWidth; pX++)
            {
                for (int pY = 0; pY < patchHeight; pY++)
                {
                    if (!PixelColor.IsMatch(color, _bitmap.GetPixel((x + pX) * _pixelMultiplier, (y + pY) * _pixelMultiplier)))
                        return false;
                }
            }

            return true;
        }
    }
}