#include <stdio.h>
#include <stdlib.h>
#include <netdb.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <lua5.3/lualib.h>
#include <lua5.3/lauxlib.h>
#include <string.h>
#include <unistd.h>


#include "oct_networking.h"

struct {
	int needs_recv;
	char recv_buffer[BUFFER_SIZE];
	//char recv_from[NI_MAXHOST];
	
	int needs_send;
	char send_buffer[BUFFER_SIZE];
	int sfd;
} oct_network_node;

int oct_network_node_init(char* port, lua_State* L) {
	oct_network_node.needs_recv = 1;
	oct_network_node.needs_send = 0;

	struct addrinfo hints;
	memset(&hints, 0, sizeof(hints));
	hints.ai_family = AF_UNSPEC; // ipv4 or ipv6
	hints.ai_socktype = SOCK_DGRAM; // datagram
	hints.ai_flags = AI_PASSIVE; // any IP address
	hints.ai_protocol = 0; // any protocol
	hints.ai_canonname = NULL;
	hints.ai_addr = NULL;
	hints.ai_next = NULL;

	struct addrinfo* result;
	int s = getaddrinfo(NULL, port, &hints, &result);
	if (s != 0) {
		//fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(s));
		return 0;
	}

	/* getaddrinfo() returns a list of address structures.
	   Try each address until we successfully bind(2).
	   If socket(2) (or bind(2)) fails, we (close the socket
	   and) try the next address. */

	struct addrinfo *rp;

	for (rp = result; rp != NULL; rp = rp->ai_next) {
		oct_network_node.sfd = socket(rp->ai_family, rp->ai_socktype,
					 rp->ai_protocol);
		if (oct_network_node.sfd == -1)
			continue;

		if (bind(oct_network_node.sfd, rp->ai_addr, rp->ai_addrlen) == 0)
			break;                  /* Success */

		close(oct_network_node.sfd);
	}

	freeaddrinfo(result);
	if (!rp) {
		return 0;
	}

	lua_pushcfunction(L, oct_network_recv_msg_lua);
	lua_setglobal(L, "oct_recv");
	lua_pushcfunction(L, oct_network_send_msg_lua);
	lua_setglobal(L, "oct_send");
	
	return 1;
}


// This runs every loop, filling the receive buffer if needed
int oct_network_recv_msg() {
	if (oct_network_node.needs_recv) {
		struct sockaddr_storage peer_addr;
		socklen_t peer_addrlen = 0; // init is needed to make valgrind happy

		// recvfrom returns -1 if nothing was received
		// Need MSG_DONTWAIT flag for nonblocking
		if (recvfrom(oct_network_node.sfd, oct_network_node.recv_buffer, BUFFER_SIZE, MSG_DONTWAIT, (struct sockaddr *) &peer_addr, &peer_addrlen) > 0) {		
			oct_network_node.needs_recv = 0;
		}
	}
	return 0;
}


int oct_network_send_msg() {
	return 0;
}

int oct_network_recv_msg_lua(lua_State* L) {
	if (!oct_network_node.needs_recv) {
		lua_pushstring(L, oct_network_node.recv_buffer);
		oct_network_node.needs_recv = 1;
	}
	else {
		lua_pushstring(L, "");
	}
	return 1;
}
int oct_network_send_msg_lua(lua_State* L) {
	return 0;
}