#include<sys/socket.h>
#include<sys/types.h>
#include<netinet/ip.h>
#include<arpa/inet.h>
#include<stdio.h>
#include<unistd.h>
#include<signal.h>
#include<stdlib.h>
#include<pthread.h>

/*
 * while(true) {
 *		next_fd  = select(client_fds)
 *		read from next_fd
 *		send an update to everybody
 * }	
 */
#include<vector>
#include<string>
using namespace std;
vector<int> client_fds;
vector<string> sqdescs;

/* Protocol:
 * 	uint16_t description_length (little endian)
 * 	actual description of the stated length
 */
char temp_buffer[65536];
void read_from_fd(int fd){
	uint16_t dlen;
	ssize_t readlen = read(fd, &dlen, 2);
	if(readlen != 2) 
		return;
	readlen = recv(fd, temp_buffer, dlen, MSG_WAITALL);
	temp_buffer[readlen] = 0;
	sqdescs.push_back(string(temp_buffer));
	// If this fails, that fd is probably disconnected, and needs to be removed from the set
	for(int fd : client_fds){
		write(fd, &dlen, 2);
		write(fd, temp_buffer, dlen);
	}
}

void *recorder_thread(void *p){
	while(1){
		if(client_fds.size() == 0) {
			usleep(1000);
			continue;
		}
		fd_set read_set;
		FD_ZERO(&read_set);
		int highest = 0;
		for(auto fd : client_fds) {
			printf("Adding fd %d to the set\n", fd);
			FD_SET(fd, &read_set);	
			if(fd > highest)
				highest = fd;
		}
		printf("Calling select, client_fds.size() = %d\n", client_fds.size());
		int nfds = select(highest + 1, &read_set, 0, 0, 0);
		printf("reading from %d fds\n", nfds);
		if(!nfds) 
			continue;
		for(auto fd : client_fds)
			if(FD_ISSET(fd, &read_set)){
				read_from_fd(fd);
				nfds--;
				if(!nfds)
					break;
			}
	}
}

int main(int argc, char ** argv){
	uint16_t port = 5143;
	int skt = socket(AF_INET, SOCK_STREAM, 0); // Step 1
	if(skt == -1){
		perror("socket");
		return 1;
	}
	
	struct sockaddr_in sad;
	sad.sin_addr.s_addr = INADDR_ANY;
	sad.sin_family = AF_INET;
retry_bind:
	sad.sin_port = htons(port);
	if( bind(skt, (struct sockaddr*)(&sad), sizeof(struct sockaddr_in)) ){ // step 2
		perror("bind");
		port++;
		goto retry_bind;
	}
	printf("Listening on port %d\n", port);
	if( listen(skt, 5) ){ // step 3
		perror("listen");
		return 1;
	}
	pthread_t thread_handle;
	pthread_create(&thread_handle, 0, recorder_thread, 0);
	while(1){
		int client_fd;
		struct sockaddr_in client_address;
		socklen_t address_size = sizeof(struct sockaddr_in);
		client_fd = accept(skt, (struct sockaddr *)(&client_address), &address_size); // step 4
		printf("Connection made from address %s\n", inet_ntoa(client_address.sin_addr));
		client_fds.push_back(client_fd);
	}
	
	return 0;
}