#include <string.h>

#include <errno.h>

#include <stdio.h>

#include <signal.h>

#include <stdlib.h>

#include <event2/bufferevent.h>

#include <event2/buffer.h>

#include <event2/listener.h>

#include <event2/util.h>

#include <event2/event.h>

#include <sys/un.h>

#include <unistd.h>

#define MAX_LINE 16384

static const char MESSAGE[] = "Hello, World!\n";

static const char PATH[] = "./roura";

static void listener_cb(struct evconnlistener *, evutil_socket_t, struct sockaddr *, int socklen, void *);

static void conn_read_cb(struct bufferevent *, void *);

static void conn_write_cb(struct bufferevent *, void *);

static void conn_event_cb(struct bufferevent *, short, void *);

static void signal_cb(evutil_socket_t, short, void *);

int main(int argc, char **argv) {

	struct event_base *base;

	struct evconnlistener *listener;

	struct event *signal_event;

	struct sockaddr_un sun;

	base = event_base_new();

	if (!base) {

		fprintf(stderr, "Could not initialize libevent!\n");

		return 1;

	}

	memset(&sun, 0, sizeof (sun));

	sun.sun_family = AF_UNIX;

	strcpy(sun.sun_path, PATH);

	listener = evconnlistener_new_bind(base, listener_cb, (void *) base,

			LEV_OPT_REUSEABLE | LEV_OPT_CLOSE_ON_FREE, -1,

			(struct sockaddr*) &sun,

			sizeof (sun));

	if (!listener) {

		fprintf(stderr, "Could not create domain socket: %s!\n", PATH);

		return 1;

	}

	signal_event = evsignal_new(base, SIGINT, signal_cb, (void *) base);

	if (!signal_event || event_add(signal_event, NULL) < 0) {

		fprintf(stderr, "Could not create/add a signal event!\n");

		return 1;

	}

	event_base_dispatch(base);

	evconnlistener_free(listener);

	event_free(signal_event);

	event_base_free(base);

	// smažeme soket na disku / soubor -- jinak by program příště spadl na evconnlistener_new_bind()

	unlink(PATH);

	printf("done\n");

	return 0;

}

static void listener_cb(struct evconnlistener *listener, evutil_socket_t fd, struct sockaddr *sa, int socklen, void *user_data) {

	struct event_base *base = (event_base *) user_data;

	struct bufferevent *bev;

	//bev = bufferevent_socket_new(base, fd, BEV_OPT_CLOSE_ON_FREE); // zavírá spojení

	bev = bufferevent_socket_new(base, fd, 0); // nezavírá spojení

	if (!bev) {

		fprintf(stderr, "Error constructing bufferevent!");

		event_base_loopbreak(base);

		return;

	}

	bufferevent_setcb(bev, conn_read_cb, conn_write_cb, conn_event_cb, NULL);

	bufferevent_setwatermark(bev, EV_READ, 0, MAX_LINE);

	bufferevent_enable(bev, EV_READ | EV_WRITE);

	printf("někdo se k nám připojil! / %p\n", bev);

	bufferevent_write(bev, MESSAGE, strlen(MESSAGE));

}

static void conn_read_cb(struct bufferevent *bev, void *user_data) {

	/* This callback is invoked when there is data to read on bev. */

	struct evbuffer *input = bufferevent_get_input(bev);

	struct evbuffer *output = bufferevent_get_output(bev);

	struct event_base *base = (event_base *) user_data;

	size_t len = evbuffer_get_length(input);

	char *data;

	data = (char*) malloc(len);

	evbuffer_copyout(input, data, len);

	printf("we got some data: %s / %d\n", data, memcmp(data, "exit", len));

	if (memcmp(data, "exit\n", len) == 0) {

		struct timeval delay = {2, 123};

		event_base_loopexit(base, &delay);

	}

	/* Copy all the data from the input buffer to the output buffer. */

	evbuffer_add_buffer(output, input);

	free(data);

}

static void conn_write_cb(struct bufferevent *bev, void *user_data) {

	struct evbuffer *output = bufferevent_get_output(bev);

	if (evbuffer_get_length(output) == 0) {

		printf("flushed answer / %p\n", bev);

		bufferevent_free(bev);

	}

}

static void conn_event_cb(struct bufferevent *bev, short events, void *user_data) {

	if (events & BEV_EVENT_EOF) {

		printf("Connection closed.\n");

	} else if (events & BEV_EVENT_ERROR) {

		printf("Got an error on the connection: %s\n", strerror(errno));

	}

	// None of the other events can happen here, since we haven't enabled timeouts

	bufferevent_free(bev);

}

static void signal_cb(evutil_socket_t sig, short events, void *user_data) {

	struct event_base *base = (event_base *) user_data;

	struct timeval delay = {2, 123};

	printf("Zachycen SIGINT (Ctrl+C); ukončuji program během %ld sekund a %ld mikrosekund.\n", delay.tv_sec, delay.tv_usec);

	event_base_loopexit(base, &delay);

}