#include <SDL/SDL.h>
#include "pixel.h"

enum direction {up=0, down=1, left=2, right=3};
struct Player {
	enum direction dir;
	int points;
	SDL_Color color;
	int posx, posy;
};

struct Player player1, player2;

void initPlayers() {
	SDL_Surface *screen = SDL_GetVideoSurface();
	player1.dir = left;
	player1.posx = screen->w / 3 * 2;
	player1.posy = screen->h / 2;
	player1.points = 0;
	player1.color.r = 255;
	player1.color.g = 0;
	player1.color.b = 0;

	player2.dir = right;
	player2.posx = screen->w / 3;
	player2.posy = screen->h / 2;
	player2.points = 0;
	player2.color.r = 0;
	player2.color.g = 255;
	player2.color.b = 0;
}

Uint32 color2rgb(SDL_Color c) {
	return SDL_MapRGB(SDL_GetVideoSurface()->format, c.r, c.g, c.b);
}

void paintPlayer(struct Player *p) {
	putpixel(SDL_GetVideoSurface(), p->posx, p->posy, color2rgb(p->color));
}

void movePlayer(struct Player *p) {
	switch(p->dir) {
		case up:
			p->posy--;
		break;
		case down:
			p->posy++;
		break;
		case left:
			p->posx--;
		break;
		case right:
			p->posx++;
		break;
	}
}

int playerCollided(struct Player* p) {
	SDL_Surface *screen = SDL_GetVideoSurface();
	if(p->posx < 0 || p->posx >= screen->w ||
	   p->posy < 0 || p->posy >= screen->h ||
	   getpixel(screen, p->posx, p->posy) != SDL_MapRGB(screen->format, 0, 0, 0))
		return 1;
	return 0;
}

int gotCollision() {
	int p1 = playerCollided(&player1);
	int p2 = playerCollided(&player2);
	if((player1.posx == player2.posx && player1.posy == player2.posy) ||
	   (p1 && p2))
		return 3; // draw game
	if(p1)
		return 1;
	if(p2)
		return 2;
	return 0;
}

void updateWindowTitle() {
	char buf[128];
	sprintf(buf, "C-Kurs Tron - %02d : %02d", player2.points, player1.points);
	SDL_WM_SetCaption(buf, 0);
}

void resetGame() {
	SDL_Surface *screen = SDL_GetVideoSurface();
	SDL_FillRect(screen, NULL, SDL_MapRGB(screen->format, 0, 0, 0));

	player1.posx = screen->w / 3*2;
	player1.posy = screen->h / 2;
	player1.dir  = left;

	player2.posx = screen->w / 3;
	player2.posy = screen->h / 2;
	player2.dir  = right;

	updateWindowTitle();
}

int main(int argc, char **argv) {
	SDL_Init(SDL_INIT_EVERYTHING);
	SDL_Surface *screen = SDL_SetVideoMode(640, 480, 32, SDL_SWSURFACE);
	
	initPlayers();
	updateWindowTitle();

	int quit = 0;
	SDL_Event event;
	while(!quit) {
		if(SDL_PollEvent(&event)) {
			if(event.type == SDL_QUIT) {
				quit = 1;
			} else if(event.type == SDL_KEYDOWN) {
				switch(event.key.keysym.sym) {
						case SDLK_LEFT:		if(player1.dir!=right)	player1.dir = left;		break;
						case SDLK_RIGHT:	if(player1.dir!=left)	player1.dir = right;	break;
						case SDLK_UP:		if(player1.dir!=down)	player1.dir = up;		break;
						case SDLK_DOWN:		if(player1.dir!=up)		player1.dir = down;		break;
						case SDLK_a:		if(player2.dir!=right)	player2.dir = left;		break;
						case SDLK_d:		if(player2.dir!=left)	player2.dir = right;	break;
						case SDLK_w:		if(player2.dir!=up)		player2.dir = up;		break;
						case SDLK_s:		if(player2.dir!=down)	player2.dir = down;		break;
						default: /* unhandled key */  break;
				}
			}
		} else {
			int coll;
			movePlayer(&player1);
			movePlayer(&player2);
			if((coll = gotCollision())) {
				if(coll == 1)
					player2.points++;
				else if(coll == 2)
					player1.points++;
				resetGame();
			} else {
				paintPlayer(&player1);
				paintPlayer(&player2);
			}
			SDL_Flip(screen);
			SDL_Delay(10);
		}
	}
	
	SDL_Quit();
	return 0;
}