#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <signal.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <pthread.h>

#define PORT 8888
#define BUFF_SIZE 8192
#define MAX_CLIENTS 125

typedef struct {
	struct sockaddr_in clients[MAX_CLIENTS + 1];
	int client_fds[MAX_CLIENTS + 1];
} DATA;

void *process_clients(void *p) {
	DATA *data = (DATA *)p;
	char buf[BUFF_SIZE];

	while (1) {
		off_t ret = read(STDIN_FILENO, buf, sizeof(buf));
		if (ret <= 0)
			continue;

		socklen_t len = sizeof(struct sockaddr_in);
		for (size_t i = 0; i < MAX_CLIENTS; i++)
			if (data->client_fds[i] != -1)
				if (sendto(data->client_fds[i], buf, ret, 0, (struct sockaddr *)&data->clients[i], len) <= 0)
					data->client_fds[i] = -1;
	}
}

int main(void) {
	signal(SIGPIPE, SIG_IGN);

	int fd = socket(AF_INET, SOCK_STREAM, 0);
	if (fd < 0)
		goto ERROR_WITHOUTCLOSE;

	struct timeval tv = {.tv_sec = 0, .tv_usec = 0};
	if (setsockopt(fd, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv)) < 0)
		goto ERROR;

	int reuse = 1;
	if (setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &reuse, sizeof(int)) < 0)
		goto ERROR;

	static struct sockaddr_in addr;
	addr.sin_family = AF_INET;
	addr.sin_port = htons(PORT);
	addr.sin_addr.s_addr = htonl(INADDR_ANY);
	if (bind(fd, (struct sockaddr *)&addr, sizeof(addr)) < 0)
		goto ERROR;

	if (listen(fd, 0) < 0)
		goto ERROR;

	/* Thread of common buffer */
	static DATA data;
	memset(data.client_fds, -1, sizeof(data.client_fds));

	pthread_t td;
	pthread_create(&td, NULL, process_clients, (void *)&data);

	/* Accept clients and update the fds buffer */
	socklen_t len = sizeof(addr);
	while (1) {
		int client_fd = accept(fd, (struct sockaddr *)&addr, &len);
		if (client_fd < 0)
			continue;

		for (size_t i = 0; i < MAX_CLIENTS; i++) {
			if (data.client_fds[i] == -1) {
				data.clients[i] = addr;
				data.client_fds[i] = client_fd;
				break;
			}
		}
	}

ERROR:
	close(fd);

ERROR_WITHOUTCLOSE:
	fprintf(stderr, "streamer: %s\n", strerror(errno));
	return 1;
}