using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using static RaytracerEngine.hitable;

namespace RaytracerEngine
{
    public partial class Form1 : Form
    {
        vec3 origin;
        vec3 lower_left_corner;
        vec3 horizontal;
        vec3 vertical;
        List<hitable> objects;
        Bitmap bmp;
        LockBitmap dbm;
		int nx = 200;
		int ny = 100;
		int ns = 3;
        bool left;
        bool right;
        bool fore;
        bool back;
        bool look_left;
        bool look_right;
        Random rnd;
        float rand { get{ return (float)rnd.NextDouble();}}
        
        public Form1()
        {
            InitializeComponent();
            //DoubleBuffered = true;
            left = false;
            right = false;
            fore = false;
            back = false;
            look_left = false;
            look_right = false;
            origin = new vec3(0, 0, 0);
            lower_left_corner = new vec3(-2.0f, -1.0f, -1.0f);
            horizontal = new vec3(4.0f, 0.0f, 0.0f);
            vertical = new vec3(0.0f, 2.0f, 0.0f);
            objects = new List<hitable>();
            //OLD VERSION
            //lower_left_corner = new vec3(-2.0f, -1.0f, -1.0f);
            //horizontal = new vec3(4.0f, 0.0f, 0.0f);
            //vertical = new vec3(0.0f, 2.0f, 0.0f);
            lower_left_corner = new vec3(2.0f, 1.0f, -1.0f);
            horizontal = new vec3(-4.0f, 0.0f, 0.0f);
            vertical = new vec3(0.0f, -2.0f, 0.0f);

            objects = new List<hitable>();
            //objects.Add(new sphere(new vec3(0, 0, -1.0f), 0.5f));
            //objects.Add(new sphere(new vec3(0, -100.5f, -1f), 100f));

            objects.Add(new sphere(new vec3(0, 0, -16), 2));
            objects.Add(new sphere(new vec3(3, -1, -14), 1));
            objects.Add(new sphere(new vec3(-3, -1, -14), 1));

            objects.Add(new triangle(new vec3(-8, -2, -20), new vec3(8, -2, -20), new vec3(8, 10, -20), 0));
            objects.Add(new triangle(new vec3(-8, -2, -20), new vec3(8, 10, -20), new vec3(-8, 10, -20), 0));
            objects.Add(new triangle(new vec3(-8, -2, -20), new vec3(8, -2, -10), new vec3(8, -2, -20), 0));
            objects.Add(new triangle(new vec3(-8, -2, -20), new vec3(-8, -2, -10), new vec3(8, -2, -10), 0));
            objects.Add(new triangle(new vec3(8, -2, -20), new vec3(8, -2, -10), new vec3(8, 10, -20), 0));

            bmp = new Bitmap(nx, ny);
            dbm = new LockBitmap(bmp);
            rnd = new Random();
            timer1.Interval = 10;            
        }

        protected override void OnLoad(EventArgs e)
        {
            timer1.Start();
            base.OnLoad(e);
        }

        protected override void OnClosed(EventArgs e)
        {
            bmp.Dispose();
            timer1.Stop();
            base.OnClosed(e);
        }

        vec3 color(ray r, int reflect)
        {
            bool hit_any = false;
            hit_record temp_rec = new hit_record();
            hit_record rec = new hit_record();
            float closest = float.MaxValue;

            foreach(var o in objects)
            {
                if (o.hit(r, 0.001f, closest, out temp_rec))
                {
                    hit_any = true;
                    closest = temp_rec.t;
                    rec = temp_rec;
                }
            }

            if (hit_any && reflect>0)
            {
                vec3 target = rec.p + rec.normal; //+ random_unit_in_sphere();
                return 0.5f * color(new ray(rec.p, target - rec.p), --reflect);
            }

            vec3 unit_dir = vec3.unit_vector(r.direction);
            float t = 0.5f * (unit_dir.y + 1.0f);
            return (1.0f - t) * new vec3(1.0f, 1.0f, 1.0f) + t * new vec3(0.5f, 0.7f, 1.0f);
        }
        
        private vec3 random_unit_in_sphere()
        {
            vec3 p;
            float o = 0f;
            do
            {
                p = 2.0f * new vec3(rand, rand, rand) - new vec3(1,1,1);
                o = p.square_length();
            } while (o >= 1f);
            return p;
        }

        private void draw_scene()
        {
            dbm.LockBits();
            for (int j = ny - 1; j >= 0; j--)
            {
                for (int i = 0; i < nx; i++)
                {
					vec3 col = new vec3(0, 0, 0);
					float u = (float)i / (float)nx;
					float v = (float)j / (float)ny;
					//for (int s = 0; s < ns; s++)
                    //{
					//	float u = (float)(i + rand) / (float)nx;
					//	float v = (float)(j + rand) / (float)ny;
						ray r = new ray(origin, lower_left_corner + u * horizontal + v * vertical);
						col = color(r, 4);
                    //}
                    //col /= (float)ns;
					int ir = (int)(255.99 * col.r);
					int ig = (int)(255.99 * col.g);
					int ib = (int)(255.99 * col.b);
					dbm.SetPixel(i, j, Color.FromArgb(255, (byte)ir, (byte)ig, (byte)ib));
                }
            }
            dbm.UnlockBits();
            pictureBox1.Image = bmp;
        }

        private void timer1_Tick(object sender, EventArgs e)
        {
            const float scale = 0.7f;//for 'walking' speed
            vec3 forwards_back = vec3.cross(horizontal, vertical);
            forwards_back.normalize();
            vec3 left_right = vec3.cross(vertical, forwards_back);
            left_right.normalize();

            if (left)
                origin = origin - left_right * scale;

            if (right)
                origin = origin + left_right * scale;

            if (fore)
                origin = origin - forwards_back * scale;

            if (back)
                origin = origin + forwards_back * scale;

            if (look_left)
            {
                //rotational matrix on camera left 25*
                lower_left_corner = vec3.turn_y(lower_left_corner, ((float)Math.PI / 16));
                horizontal = vec3.turn_y(horizontal, ((float)Math.PI / 16));
                vertical = vec3.turn_y(vertical, ((float)Math.PI / 16));
            }

            if (look_right)
            {
                //rotational matrix on camera right 25*
                lower_left_corner = vec3.turn_y(lower_left_corner, -((float)Math.PI / 16));
                horizontal = vec3.turn_y(horizontal, -((float)Math.PI / 16));
                vertical = vec3.turn_y(vertical, -((float)Math.PI / 16));
            }

            draw_scene();
            pictureBox1.Refresh();
        }

        protected override void OnPaint(PaintEventArgs e)
        {
            draw_scene();
            base.OnPaint(e);
        }
        
        protected override void OnKeyDown(KeyEventArgs e)
        {
            if (e.KeyValue == 'A')
                left = true;

            if (e.KeyValue == 'D')
                right = true;

            if (e.KeyValue == 'W')
                fore = true;

            if (e.KeyValue == 'S')
                back = true;

            if (e.KeyValue == 'Q')
                look_left = true;

            if (e.KeyValue == 'E')
                look_right = true;

            base.OnKeyDown(e);
        }

        protected override void OnKeyUp(KeyEventArgs e)
        {
            if (e.KeyValue == 'A')
                left = false;

            if (e.KeyValue == 'D')
                right = false;

            if (e.KeyValue == 'W')
                fore = false;

            if (e.KeyValue == 'S')
                back = false;

            if (e.KeyValue == 'Q')
                look_left = false;

            if (e.KeyValue == 'E')
                look_right = false;

            base.OnKeyUp(e);
        }
    }
}