#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <pthread.h>
#include <linux/input.h>
#include <stdlib.h>

#define EV_PRESSED 1

// bounds
#define MAX_X 55
#define MIN_X 25
#define MAX_Y 20
#define MIN_Y 10


int is_possible_move(int y, int x) {
    return MIN_X < x && x < MAX_X && MIN_Y < y && y < MAX_Y;
}


int quit = 0;
int keyboard;

int init_keyboard() {
    /*
     * Check before start
     * command ->   grep -E 'Handlers|EV=' /proc/bus/input/devices | grep -B1 '120013' | grep -Eo 'event[0-9]+'
     */
    char *device = "/dev/input/event4";
    if ((getuid()) != 0) {
        printf("You are not root! This may not work...\n");
        return -1;
    }

    if ((keyboard = open(device, O_RDONLY)) == -1) {
        printf("%s is not a valid device.\n", device);
        return -1;
    }

    return 0;
}

void * update_keyboard() {
    struct input_event event;
    const char ESC[] = "\033";
    char cmd[50];

    int y = 15;
    int x = 30;

    system("stty -echo");
    while (1) {
        read(keyboard, &event, sizeof(struct input_event));
        if (event.type == EV_KEY) {
            if (event.value == EV_PRESSED) {
                switch (event.code) {
                    case KEY_UP: {
                        if (is_possible_move(y - 1, x)) {
                            y--;
                            system("clear");
                            sprintf(cmd, "printf '%s[%d;%dH*'", ESC, y, x);
                            system(cmd);
                        }
                        break;
                    }
                    case KEY_DOWN: {
                        if (is_possible_move(y + 1, x)) {
                            y++;
                            system("clear");
                            sprintf(cmd, "printf '%s[%d;%dH*'", ESC, y, x);
                            system(cmd);
                        }
                        break;
                    }
                    case KEY_LEFT: {
                        if (is_possible_move(y, x - 1)) {
                            x--;
                            system("clear");
                            sprintf(cmd, "printf '%s[%d;%dH*'", ESC, y, x);
                            system(cmd);
                        }
                        break;
                    }
                    case KEY_RIGHT: {
                        if (is_possible_move(y, x + 1)) {
                            x++;
                            system("clear");
                            sprintf(cmd, "printf '%s[%d;%dH*'", ESC, y, x);
                            system(cmd);
                        }
                        break;
                    }
                    case KEY_ESC: {
                        quit = 1;
                    }
                }
            }
        }
    }
}

int main() {
    if (init_keyboard() != 0) return -1;

    pthread_t thread;
    int id = 1;
    int result = 0;

    result = pthread_create(&thread, NULL, update_keyboard, &id);
    if (result != 0) {
        printf("Create thread failed\n");
        return -1;
    }

    while(!quit) {
    }

    return 0;
}