using System;
using System.IO;

using ImageSharp;
using ImageSharp.PixelFormats;

using OpenTK.Graphics.OpenGL4;
using OpenTK;

using org.nhengine.graphics;

namespace nhengine
{
	public class SquaredMap : GLObject
	{
		private int width,
					height;

		private float[] heightMap;

		public SquaredMap(int width,int height)
			:base( 12 * width * height )
		{
			this.width = width;
			this.height = height;

			this.heightMap = new float[ (width + 1) * (height + 1) ];

			normalsEnabled = true;

			generateHeightMap();

			computeGL();
			updateGL();
		}
		
		public SquaredMap(Image heightMap)
		:base(12 * heightMap.Width * heightMap.Height)
		{
			this.width = heightMap.Width;
			this.height = heightMap.Height;

			this.heightMap = new float[ (width + 1) * (height + 1) ];

			normalsEnabled = true;

			loadHeightMap(heightMap);

			computeGL();
			updateGL();

		}
		

		public void generateHeightMap(){
			Random rand = new Random();

			for (int y = 0; y <= height; y++)
			{
				for (int x = 0; x <= width; x++)				
				{
					float h = (float)rand.NextDouble();
					heightMap[x + (y * width)] = (float)(256 * (h * h));
				}
			}
		}
		
		public void loadHeightMap(Image _heightMap){
		
			Rgba32[] pixels = _heightMap.Pixels;
		
			for (int y = 0; y <= height; y++)
			{
				for (int x = 0; x <= width; x++)				
				{
					Rgba32 pixel = pixels[ x + (y * _heightMap.Width)];
					float h = (pixel.R + pixel.G + pixel.B);
					heightMap[x + (y * width)] = (float)(h);
				}
			}
		}

		public void computeGL(){
			float left,
					right,
					bottom,
					top,
					vcenter,
					hcenter;

			Console.WriteLine("Creating geometry");

			for (int x = 0; x < width; x++)
			{
				for (int y = 0; y < height; y++)
				{
					int i = x + ((width + 1) * y);
					int j = x + ((width + 1) * (y + 1));

					float[] h = new float[4];
					h[0] = heightMap[i];
					h[1] = heightMap[i+1];
					h[2] = heightMap[j];
					h[3] = heightMap[j+1];

					float ah = (h[0] + h[1] + h[2] + h[3]) / 4.0f;

					left = 128 * x;
					right = 128 * (x + 1);
					bottom = 128 * y;
					top = 128 * (y + 1);
					vcenter = (top + bottom) / 2.0f;
					hcenter = (left + right) / 2.0f;

					int b = 4 * (x + (width * y));

					setTriangle(
						b,
						new Vector3(left,	top,	h[2]),
						new Vector3(right,	top,	h[3]),
						new Vector3(hcenter,vcenter,ah)
					);
                    setTriangle(
						b + 1,
						new Vector3(right, top, h[3]),
						new Vector3(right, bottom, h[1]),
						new Vector3(hcenter, vcenter, ah)
					);
	               setTriangle(
						b + 2,
						new Vector3(right, bottom, h[1]),
						new Vector3(left, bottom, h[0]),
						new Vector3(hcenter, vcenter, ah)
					);
					setTriangle(
						b + 3,
						new Vector3(left, bottom, h[0]),
						new Vector3(left, top, h[2]),
						new Vector3(hcenter, vcenter, ah)
					);
				}
			}

			Console.WriteLine("Coloring...");

			for (int n = 0; n < vertices.Length / 3;n++){
				float _h = vertices[(3 * n) + 2] / 512.0f;
            	setColor(
					n,
					new Vector4(
							0.3f + (0.7f * _h),
					        0.2f + (0.8f * _h),
					        0.4f + (0.6f * _h),
							1.0f
						)
					);
			}


		}


	}
}