#include <linux/input.h>
#include <linux/uinput.h>
#include <fcntl.h> 
#include <unistd.h>
#include <stdio.h>
#include <string.h> /* memset */
#include <stdlib.h> /* EXIT_FAILURE */

int keys[] = {
	KEY_Q, /* prev */
	KEY_E, /* next */
	KEY_Z, /* shoot */
	KEY_W,
	KEY_A,
	KEY_S,
	KEY_D,
	KEY_P, /* pause */
	KEY_BACKSPACE, /* really "backspace" */
};

#define ARRAY_SIZE(a) (sizeof (a) / sizeof *(a) )

int main() {
	int i;
	int fd = open("/dev/uinput", O_WRONLY);
	if (fd < 0) {
		perror("open");
		return 1;
	}
	if (ioctl(fd, UI_SET_EVBIT, EV_KEY) < 0) {
		perror("Cannot set EV_KEY bit");
		goto err_close;
	}
	if (ioctl(fd, UI_SET_EVBIT, EV_SYN) < 0) {
		perror("Cannot set EV_SYN bit");
		goto err_close;
	}
	for (i = 0; i < ARRAY_SIZE(keys); ++i) {
		if (ioctl(fd, UI_SET_KEYBIT, keys[i]) < 0) {
			perror("SET_KEYBIT");
			goto err_close;
		}
	}

	struct uinput_user_dev uidev;
	memset(&uidev, 0, sizeof(uidev));
	snprintf(uidev.name, UINPUT_MAX_NAME_SIZE, "Boxhead");
	if (write(fd, &uidev, sizeof(uidev)) < 0) {
		perror("write uinput struct");
		goto err_close;
	}

	if (ioctl(fd, UI_DEV_CREATE) < 0) {
		perror("UI_DEV_CREATE");
		goto err_close;
	}

	unsigned int code, is_pressed;
	printf("Waiting for input...\n");
	struct input_event ev;
	memset(&ev, 0, sizeof(ev));
	while (scanf("%u %u", &code, &is_pressed) == 2) {
		if (code >= 1 && code <= ARRAY_SIZE(keys)) {
			ev.type = EV_KEY;
			ev.code = keys[code - 1];
			ev.value = !!is_pressed;
			//printf("code=%u value=%u\n", ev.code, ev.value);
			if (write(fd, &ev, sizeof(ev)) < 0)
				perror("write key");
			/* input_sync() */
			ev.type = EV_SYN;
			ev.code = SYN_REPORT;
			ev.value = 0;
			if (write(fd, &ev, sizeof(ev)) < 0)
				perror("write sync");
		} else {
			fprintf(stderr, "Unexpected key: %u (%#02x)\n", code, code);
			break;
		}
	}
	if (ioctl(fd, UI_DEV_DESTROY) < 0)
		perror("Cannot destroy device");
	if (close(fd) < 0)
		perror("close");
	return 0;
err_close:
	if (close(fd) < 0)
		perror("close");
	return EXIT_FAILURE;
}