#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

int main()
{
    srand(time(NULL));

    int x = 0, y = 0, temp = 0;
    int end = 0;
    char action = 'l';

    int field[4][4];
    for(int i=0;i<16;i++) {
        field[0][i] = i+1;
    }
    field[3][3] = 0;
    for(int i=0;i<8;i++) {
        int x2 = rand() % 4;
        int y2 = rand() % 4;
        temp = field[x2][y2];
        x = rand() % 4;
        y = rand() % 4;
        field[x2][y2] = field[x][y];
        field[x][y] = temp;
    }

    for(int i=0;i<16;i++) {
        if(field[0][i] == 0) {
            x = i / 4;
            y = i % 4;
            break;
        }
    }

    printf("Commands: u - up, d - down, l - left, r - right\n\n\n");

    while(!end) {
        for(int i=0;i<4;i++) {
            for(int j=0;j<4;j++)
                printf("%2d ", field[i][j]);
            printf("\n");
        }
        printf("action> ");
        if(scanf("%c", &action) != 1) {
            printf("Invalid: not enough or too many commands\n");
            continue;
        }
        fflush(stdin);
        switch(action) {
            case 'u':
                if(x > 0) {
                    temp = field[x][y];
                    field[x][y] = field[x-1][y];
                    field[x-1][y] = temp;
                    x = x - 1;
                }
                break;
            case 'd':
                if(x < 3) {
                    temp = field[x][y];
                    field[x][y] = field[x+1][y];
                    field[x+1][y] = temp;
                    x = x+1;
                }
                break;
            case 'l':
                if(y > 0) {
                    temp = field[x][y];
                    field[x][y] = field[x][y-1];
                    field[x][y-1] = temp;
                    y = y - 1;
                }
                break;
            case 'r':
                if(y < 3) {
                    temp = field[x][y];
                    field[x][y] = field[x][y+1];
                    field[x][y+1] = temp;
                    y = y + 1;
                }
                break;
            default:
                printf("Invalid command\n");
        }

        for(int i=0;i<16;i++) {
            if(i == 15) {
                end = 1;
                break;
            }
            if(field[0][i] != i+1)
                break;
        }

    }

    printf("You won!\n");

    return 0;
}