// C includes
#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<sys/stat.h>
#include<fcntl.h>

// C++ includes
#include<thread>
#include<vector>
using namespace std;

struct message {
	uint8_t type;
	uint16_t length;
	char recipient_name[32];
	char sender_name[32];
	char *message;
}__attribute__((packed));

int read_message(struct message* m, int fd){
	if(67 != recv(fd, m, 67, MSG_WAITALL))
		return 1;
	m->message = (char*)malloc(m->length);
	if(m->length != recv(fd, m->message, m->length, MSG_WAITALL))
		return 2;
	return 0;
}

void send_message(struct message* m, int fd){
	write(fd, m, 67);
	write(fd, m->message, m->length);
}

vector<int> client_fds;

/* Client should send a length of filename, then filename */
void handle_client(int client_fd, struct sockaddr_in client_address){
	struct message m;
	client_fds.push_back(client_fd);
	while(1){
		if(read_message(&m, client_fd))
			break;
		printf("Received message from %s to %s (%d bytes):  %s\n", m.sender_name, m.recipient_name, m.length, m.message);
		for(int cfd : client_fds)
			if(cfd != client_fd)
				send_message(&m, cfd);
		free(m.message);
		
	}
	printf("Closing connection with client %d\n", client_fd);
	// Remove from list of clients before we close
	for(int i = 0; i < client_fds.size(); i++){
		if(client_fds[i] == client_fd){
			client_fds.erase(client_fds.begin() + i);  // Could this cause a race condition?
		}
	}

	close(client_fd);
}

int main(int argc, char ** argv){
	struct sockaddr_in sad;
	sad.sin_port = htons(5143);
	sad.sin_addr.s_addr = INADDR_ANY;
	sad.sin_family = AF_INET;

	int skt = socket(AF_INET, SOCK_STREAM, 0); // Step 1
	if(skt == -1){
		perror("socket");
		return 1;
	}
	if( bind(skt, (struct sockaddr*)(&sad), sizeof(struct sockaddr_in)) ){ // step 2
		perror("bind");
		return 1;
	}
	if( listen(skt, 5) ){ // step 3
		perror("listen");
		return 1;
	}	
	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

		thread client_thread(handle_client, client_fd, client_address);
		client_thread.detach();
	}

	return 0;
}