#include <SDL2/SDL.h>
#include <SDL2/SDL_image.h>
#include <SDL2/SDL_timer.h>

#include <stdio.h>
#include <math.h>
#include <errno.h>
#include <time.h>

#include "textures/textures.ppm"

#define SPEED 1.5
#define RADSPD 0.05
// #define DELAY 1
#define MAPX 16
#define MAPY 16
#define PI 3.1415926535
#define DEG 0.01745329
#define HEIGHT 512
#define WIDTH 960
#define TILESIZE 32
#define SQRTTILE 5
#define MAPSCALE 2

struct player
{
	float x; 
	float y; 
	float dx; 
	float dy; 
	float th;
};

float dist(float x1, float y1, float x2, float y2)
{
	return ( sqrt((x2-x1)*(x2-x1)+(y2-y1)*(y2-y1)) );
}

int processEvents(SDL_Window *window, struct player *P, int map[], int *mpbool, clock_t *prevframe)
{
	// Вычисление FPS
	clock_t frame;
	float fps;
	
	frame = clock();
	fps = CLOCKS_PER_SEC/(double)(frame - *prevframe);
	*prevframe = frame;
	printf("%d\r", (int)fps);

	int done = 0;
	SDL_Event event;

	int xoff = 0;
	if((P->dx)>0) {xoff = 20;} else {xoff = -20;}

	int yoff = 0;
	if((P->dy)>0) {yoff = 20;} else {yoff = -20;}

	int px64 = (int)(P->x) >> SQRTTILE;
	int py64 = (int)(P->y) >> SQRTTILE;

	int pxadd = (int)(P->x + xoff) >> SQRTTILE, pyadd = (int)(P->y + yoff) >> SQRTTILE;
	int pxsub = (int)(P->x - xoff) >> SQRTTILE, pysub = (int)(P->y - yoff) >> SQRTTILE;

	while(SDL_PollEvent(&event))
	{
		switch(event.type)
		{	
			case SDL_WINDOWEVENT_CLOSE:
			{
				if(window)
				{
					SDL_DestroyWindow(window);
					window = NULL;
					done = 1;
				}
			}
			break;
			
			case SDL_KEYDOWN:
			{
				switch(event.key.keysym.sym)
				{
					case SDLK_ESCAPE:
						done = 1;
						break;
					case SDLK_m: // карта
						*mpbool = !*mpbool;
						break;
					case SDLK_e: // взаимодействие
						if(map[pyadd*MAPX + pxadd] == 4) // дверь
							map[pyadd*MAPX + pxadd] = 0;
				}
			}
			break;
			
			case SDL_QUIT:
				done = 1;
			break;
		}
	}

	const Uint8 *state = SDL_GetKeyboardState(NULL);
	if(state[SDL_SCANCODE_A])
		P->th -= RADSPD;


	if(state[SDL_SCANCODE_W]) {
		if(map[py64*MAPX + pxadd]==0) {P->x += P->dx;}
		if(map[pyadd*MAPX + px64]==0) {P->y += P->dy;}
	}
	if(state[SDL_SCANCODE_S]) {
		if(map[py64*MAPX + pxsub]==0) {P->x -= P->dx;}
		if(map[pysub*MAPX + px64]==0) {P->y -= P->dy;}
	}
	if(state[SDL_SCANCODE_D])
		P->th += RADSPD; 

	if(P->th < 0)
		P->th = 2*PI - 0.00001;
	if(P->th > 2*PI)
		P->th = 0.0;

	P->dx = cos(P->th)*(75/fps);
	P->dy = sin(P->th)*(75/fps);

	return done;
}

void drawLevel(SDL_Renderer *renderer, int map[], struct player P)
{
	for(int y = 0; y<MAPY; y++)
		for(int x = 0; x<MAPX; x++)
		{
			if(map[y*MAPX + x] > 0)
			{
				SDL_SetRenderDrawColor(renderer, 255, 255, 255, 128);
			} else {
				SDL_SetRenderDrawColor(renderer, 0, 0, 0, 128);
			}

				SDL_Rect wall = {x*TILESIZE/MAPSCALE, y*TILESIZE/MAPSCALE, TILESIZE/MAPSCALE-2, TILESIZE/MAPSCALE-2};
				SDL_RenderFillRect(renderer, &wall);
		}		
}

void drawPlayer(SDL_Renderer *renderer, struct player P)
{
		SDL_Vertex arrow[3];
		arrow[0].position.x = (P.x+7*cos(P.th-PI/2))/MAPSCALE;
		arrow[0].position.y = (P.y+7*sin(P.th-PI/2))/MAPSCALE;
		arrow[0].color.r = 255;
		arrow[0].color.g = 220;
		arrow[0].color.b = 0;
		arrow[0].color.a = 128;

		arrow[1].position.x = (P.x+7*cos(P.th+PI/2))/MAPSCALE;
		arrow[1].position.y = (P.y+7*sin(P.th+PI/2))/MAPSCALE;
		arrow[1].color.r = 255;
		arrow[1].color.g = 220;
		arrow[1].color.b = 0;
		arrow[1].color.a = 128;

		arrow[2].position.x = (P.x+20*cos(P.th))/MAPSCALE;
		arrow[2].position.y = (P.y+20*sin(P.th))/MAPSCALE;
		arrow[2].color.r = 255;
		arrow[2].color.g = 220;
		arrow[2].color.b = 0;
		arrow[2].color.a = 128;

		SDL_RenderGeometry(renderer, NULL, arrow, 3, NULL, 0);
}

void drawRays(SDL_Renderer *renderer, struct player P, int map[], int mapF[], int mapC[])
{
	int mx, my, mp, dof, texture_iv, texture_ih, texture_i;
	float rx, ry, ra, xo, yo, px, py, hlen, vlen, sinra, hx, hy, vx, vy, rdist;
	ra=P.th-30*DEG;
	if(ra<0)
		ra += 2*PI;
	if(ra>2*PI)
		ra -= 2*PI;

	px = P.x;
	py = P.y;
	float antan;
	for(int r = 0; r<240; r++)
	{
		// ----- по горизонтальным -----
		hlen = 100000;
		dof = 0;
		sinra = sin(ra);
		if(sinra<-0.001)	// "вверх"
		{
			antan=-1.0/tan(ra);
			ry = (((int)py>>SQRTTILE)<<SQRTTILE)-0.0001;
			rx = (py-ry)*antan+px;
			yo = -TILESIZE;
			xo = -yo*antan;
		} else {
		if(sinra>0.001)
		{
			antan=-1.0/tan(ra);
			ry = (((int)py>>SQRTTILE)<<SQRTTILE)+TILESIZE;
			rx = (py-ry)*antan+px;
			yo = TILESIZE;
			xo = -yo*antan;
		}
		else
		{
			rx = px;
			ry = py;
			dof = 16;
		}}

		while(dof<16)
		{	
			mx = (int)(rx)>>SQRTTILE;
			my = (int)(ry)>>SQRTTILE;
			mp = my*MAPX+mx;

			if(mp > 0 && mp < MAPX*MAPY && map[mp]>0){
				hx = rx;
				hy = ry;
				hlen = dist(px, py, hx, hy);
				texture_ih = map[mp]-1;
				dof = 16;
			} else {
				rx += xo;
				ry += yo;
				dof++;
			}
		}
		// ----- по вертикальным -----
		dof = 0;
		vlen = 100000;
		float cosra = cos(ra);
		if(cosra<-0.001)	// "влево"
		{
			antan=-tan(ra);
			rx = (((int)px>>SQRTTILE)<<SQRTTILE)-0.0001;
			ry = (px-rx)*antan+py;
			xo = -TILESIZE;
			yo = -xo*antan;
		} else {
		if(cosra>0.001)
		{
			antan=-tan(ra);
			rx = (((int)px>>SQRTTILE)<<SQRTTILE)+TILESIZE;
			ry = (px-rx)*antan+py;
			xo = TILESIZE;
			yo = -xo*antan;
		}
		else
		{
			rx = px;
			ry = py;
			dof = 16;
		}}

		while(dof<16)
		{	
			mx = (int)(rx)>>SQRTTILE;
			my = (int)(ry)>>SQRTTILE;
			mp = my*MAPX+mx;

			if(mp > 0 && mp < MAPX*MAPY && map[mp]>0){
				vx = rx;
				vy = ry;
				vlen = dist(px, py, vx, vy);
				texture_iv = map[mp]-1;
				dof = 16;
			} else {
				rx += xo;
				ry += yo;
				dof++;
			}
		}

		float shade = 1;
		if(vlen < hlen) 
		{ 
			rx = vx; ry = vy; rdist = vlen; texture_i = texture_iv;
		}
		else { rx = hx; ry = hy; rdist = hlen; shade = 0.6; texture_i = texture_ih;
		}

		// ----- Рисуем стены -----

		float corran = P.th - ra;
		if(corran<0)
			corran += 2*PI;
		if(corran>2*PI)
			corran -= 2*PI;
		rdist *= cos(corran); 						// рыбий глаз

		float lineh = (TILESIZE*HEIGHT)/rdist;
		float ty_step = 32.0 / lineh;
		float ty_offset = 0;
		
		if(lineh>HEIGHT){
			ty_offset = (lineh-HEIGHT)/2.0;
			lineh=HEIGHT;
		}
		float lineo = HEIGHT/2 - lineh/2;

		
		float ty = ty_offset*ty_step; // Текстурирование
		float tx;
		if(vlen > hlen) {
			tx = (int)(rx/(TILESIZE/32)) % 32;
			if(ra < 180*DEG) {tx = 31-tx;}
		} else {
			tx = (int)(ry/(TILESIZE/32)) % 32;
			if(ra>90*DEG && ra < 270*DEG) {tx = 31-tx;}
		}

		/*int y;
		for(y = 0; y<lineh; y++, ty+=ty_step)
		{
			int c = textures[(int)(ty)*32+(int)tx]*255*shade;
			// SDL_SetRenderDrawColor(renderer, c/rdist*15, c/rdist*15, c/rdist*15, 255);
			SDL_SetRenderDrawColor(renderer, c, c, c, 255);
			SDL_Rect line = {r*4, lineo+y, 4, 4};
			SDL_RenderFillRect(renderer, &line);
		}*/
		int y;
		for(y = 0; y<lineh; y++, ty+=ty_step)
		{
			int index = ((int)ty*32 + (int)tx)*3+(texture_i*32*32*3);
			int red = textures[index]*shade;
			int green = textures[index+1]*shade;
			int blue = textures[index+2]*shade;
	
			SDL_SetRenderDrawColor(renderer, red, green, blue, 255);
			SDL_Rect px = {r*4, lineo+y, 4, 4};
			SDL_RenderFillRect(renderer, &px);
		}

		//   ----- рисуем пол -----
		for(y = lineo+lineh; y<HEIGHT; y++)
		{
			float dy = y - (HEIGHT/2.0);
			tx = P.x  + cos(ra)*(0.4941406*HEIGHT)*32/(dy*cos(corran));
			ty = P.y  + sin(ra)*(0.4941406*HEIGHT)*32/(dy*cos(corran));
			int mp = mapF[(int)(ty/32.0)*MAPX + (int)(tx/32.0)]*32*32;

			int index = (((int)(ty)&31)*32 + ((int)(tx)&31))*3 + mp*3;
			int red = textures[index]*0.7;
			int green = textures[index+1]*0.7;
			int blue = textures[index+2]*0.7;

			// float c = textures[index]*0.7;
			// SDL_SetRenderDrawColor(renderer, c*dy/255, c*dy/255, c*dy/255, 255);
			SDL_SetRenderDrawColor(renderer, red, green, blue, 255);
			SDL_Rect line = {r*4, y, 4, 4};
			SDL_RenderFillRect(renderer, &line);

			mp = mapC[(int)(ty/32.0)*MAPX + (int)(tx/32.0)]*32*32;
			index = (((int)(ty)&31)*32 + ((int)(tx)&31))*3 + mp*3;
			red = textures[index]*0.7;
			green = textures[index+1]*0.7;
			blue = textures[index+2]*0.7;
			// SDL_SetRenderDrawColor(renderer, c*dy/255, c*dy/255, c*dy/255, 255);
			SDL_SetRenderDrawColor(renderer, red, green, blue, 255);
			SDL_Rect line_c = {r*4, HEIGHT-y, 4, 4};
			SDL_RenderFillRect(renderer, &line_c);

		}

		ra += 0.25*DEG;
		if(ra<0)
			ra += 2*PI;
		if(ra>2*PI)
			ra -= 2*PI;
	}
}

void Render(SDL_Renderer *renderer, int map[], int mapF[], int mapC[], struct player P, int *mpbool)
{	
	SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255); // фон
	SDL_RenderClear(renderer);
	drawRays(renderer, P, map, mapF, mapC);
	
	if(*mpbool) {
		drawLevel(renderer, map, P);
		drawPlayer(renderer, P);
	}

	SDL_RenderPresent(renderer);
	// SDL_Delay(DELAY);
}

int main(void)
{
	SDL_Window *window;
	SDL_Renderer *renderer;
	
	SDL_Init(SDL_INIT_VIDEO);

	window = SDL_CreateWindow("Raycast",
				  SDL_WINDOWPOS_UNDEFINED,
				  SDL_WINDOWPOS_UNDEFINED,
				  WIDTH,
				  HEIGHT,
				  0);

	renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED);
	SDL_SetRenderDrawBlendMode(renderer, SDL_BLENDMODE_BLEND);
	struct player P = {50, 50, 0, 0, PI/2};
	clock_t prevframe = clock();
	clock_t *pnt_pframe = &prevframe;

	int layoutW[MAPX*MAPY] = 
	{
	  /*				    10  12  14  */
		3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,//0
		3,0,0,3,3,0,0,0,0,0,0,0,0,0,0,3,//1
		3,0,0,3,3,0,3,0,0,3,0,0,3,0,0,3,//2
		3,0,0,3,3,0,0,0,0,0,0,0,0,0,0,3,//3
		3,0,0,3,3,0,3,0,0,3,0,0,3,0,0,3,//4
		3,0,0,3,3,0,0,0,0,0,0,0,0,0,0,3,//5
		3,0,0,3,3,3,3,3,3,3,3,3,3,0,0,3,//6
		3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,//7
		3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,//8
		3,3,4,3,3,0,2,0,2,0,2,0,2,0,0,3,//9
		3,0,0,0,3,3,3,3,3,4,3,3,3,0,0,3,//10
		3,3,0,3,3,0,0,0,0,0,0,3,3,0,0,3,//11
		3,0,0,0,3,0,3,3,3,3,0,3,3,0,0,3,//12
		3,3,0,3,3,0,3,3,3,3,3,3,3,0,0,3,//13
		3,0,0,0,3,0,0,0,0,0,0,0,4,0,0,3,//14
		3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,//15
	  /*0,1,2,3,4,5,6,7,8,9,  11  13  15*/
	};

	int layoutF[MAPX*MAPY] = 
	{
	  /*                    10  12  14  */
		0,0,0,0,0,0,0,0,0,0,0,0,0,2,2,2,//0
		0,0,0,0,0,0,0,0,0,0,0,0,0,2,2,2,//1
		0,0,0,0,0,0,0,0,0,0,0,0,0,2,2,2,//2
		0,0,0,0,0,0,0,0,0,0,0,0,0,2,2,2,//3
		0,0,0,0,0,0,0,0,0,0,0,0,0,2,2,2,//4
		0,0,0,0,0,0,0,0,0,0,0,0,0,2,2,2,//5
		0,0,0,0,0,0,0,0,0,0,0,0,0,2,2,2,//6
		1,1,1,0,0,0,0,0,0,0,0,0,0,2,2,2,//7
		1,1,1,0,0,0,0,0,0,0,0,0,0,2,2,2,//8
		0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,//9
		0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,//10
		0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,//11
		0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,//12
		0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,//13
		0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,//14
		0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,//15
	  /*0,1,2,3,4,5,6,7,8,9,  11  13  15*/
	};

	int layoutC[MAPX*MAPY] = 
	{
	  /*                    10  12  14  */
		0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,//0
		0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,//1
		0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,//2
		0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,//3
		0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,//4
		0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,//5
		0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,//6
		0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,//7
		0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,//8
		0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,//9
		0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,//10
		0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,//11
		0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,//12
		0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,//13
		0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,//14
		0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,//15
	  /*0,1,2,3,4,5,6,7,8,9,  11  13  15*/
	};

	int done = 0;	// bool завершения программы
	int mpbool = 0; // bool вкл/выкл карты

	while(!done)
	{
	// проверка событий
		if(processEvents(window, &P, layoutW, &mpbool, pnt_pframe) == 1)
			done = 1;
	//rendering 
		Render(renderer, layoutW, layoutF, layoutC, P, &mpbool);
	}

	SDL_DestroyWindow(window);
	SDL_DestroyRenderer(renderer);

	SDL_Quit();
	printf("!%d!", errno);
	return 0;
}