/**
*
* 2ls10: a clone of the popular 2048 game
*
* (c) 2019 - Vincenzo "KatolaZ" Nicosia <katolaz@freaknet.org>
*
* See COPYING for terms and conditions
*
*/

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <termios.h>
#include <unistd.h>

#define cond(x) ((t) ? (x)/n : (x)%n)

int st[1<<8], lo, li, ls, m, pt, n, pl, t;
char nf;
struct termios t1, t2;

void clean(char *str){
	if (str) printf("%s\n", str);
	tcsetattr(0, TCSANOW, &t1);
	exit(0);	
}

int dash(int i){
	return i?
		putchar('-') + dash(i-1):0;
		}
		
int line(int i){
	return putchar('+') + (i ?
		dash(6)+ line(i-1):
		putchar(10));	
}

int valid_move(){
	int i;
	for (i=0; i<n*n - 1; i++){
		if ((i%n < n-1 && st[i]==st[i+1]) || (i/n < n-1 && st[i] == st[i+n]))
			return 1;
	}
	return 0;
}

void print_state(){
	int i, j,v;
	printf("\033[2J\033[1;1HScore: %d\n", pt);
	line(n);
	for (i=0; i<n; i++){
		printf("|");
		for(j=0; j<n; j++){
			v=st[n*i+j];
			if (v > 0)
				printf("%5d |", 1<<v);
			else printf("      |");
		}
		printf("\n");
	}
	line(n);
}

void set_rnd(){
	int i;
	while(nf){
		i = rand();
		if (!st[i%(n*n)]){
			st[i%(n*n)] = 1 + (i%8==0);
			if (! --nf) break;
			return;
		}
	}
	if (!valid_move()){
		print_state();	
		clean("no more moves");
	}
}


void shift(int j){
	int num_empty=0;
	do{
		if (! st[j]) /* empty*/
			num_empty -= li;
		else  if (num_empty){
			st[j + num_empty] = st[j];
			st[j] ^= st[j];
		}
		j += li;
	} while (j >= 0 && cond(j) != ls);
}

void merge(int j){
	do {
		if (st[j] && st[j] == st[j-li]){
			st[j-li] += 1;
			if (st[j-li] == 11) pl ^= pl;
			pt += 1<<st[j-li];
			st[j] ^= st[j];
			nf ++;
		}
		j += li;
	} while( j>= 0 && cond(j) != ls);
}

void update(){
	int i;
	for(i =0; i<n; i++){
		shift(m * i + lo);
		merge(m * i + lo + li);
		shift(m * i + lo);	
	}
}

void play(){
	set_rnd();
	pt = 0;
	pl = 1;
	while(pl){
		set_rnd();
		print_state();
		switch(getchar()){
			case 'l':
				lo = ls = n-1; 
				li = -1;
				m = n;
				t = 0;
				break;
			case 'h':
				lo = ls = 0;
				li = 1;
				m = n;
				t = 0;
				break;
			case 'j':
				lo = n * (n-1);
				li = -n;
				ls = -1;
				m = 1;
				t=1;
				break;
			case 'k':
				lo = 0;
				li = ls = n;
				m = 1;
				t=1;
				break;
			case 'q':
				clean("Thanks!");

		}
		update();
	}
	print_state();
	clean("you won!");
}


int main(int argc, char *argv[]){
 	srand(time(NULL));	
 	//srand(12345);
	n = 4;
	if (argc > 1) {
		n = atoi(argv[1]);
		if (n< 2 || n > 16){
			fprintf(stderr, "Usage: 2ls10 [2-16]\n");	
			exit(1);
		}
	}
	nf = n * n;	
	tcgetattr(0, &t1);
	t2 = t1;
	t2.c_lflag &= ~(ICANON | ECHO);
	tcsetattr(0, TCSANOW, &t2);

	play();
}