/**
 * libzt API example
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <string>

#include "ZeroTierSockets.h"

bool nodeReady = false;
bool networkReady = false;

// Example callbacks
void myZeroTierEventCallback(void *msgPtr)
{
	struct zts_callback_msg *msg = (struct zts_callback_msg *)msgPtr;

	// Node events
	if (msg->eventCode == ZTS_EVENT_NODE_ONLINE) {
		printf("ZTS_EVENT_NODE_ONLINE --- This node's ID is %llx\n", msg->node->address);
		nodeReady = true;
	}
	if (msg->eventCode == ZTS_EVENT_NODE_OFFLINE) {
		printf("ZTS_EVENT_NODE_OFFLINE --- Check your physical Internet connection, router, firewall, etc. What ports are you blocking?\n");
		nodeReady = false;
	}
	if (msg->eventCode == ZTS_EVENT_NODE_NORMAL_TERMINATION) {
		printf("ZTS_EVENT_NODE_NORMAL_TERMINATION\n");
	}

	// Virtual network events
	if (msg->eventCode == ZTS_EVENT_NETWORK_NOT_FOUND) {
		printf("ZTS_EVENT_NETWORK_NOT_FOUND --- Are you sure %llx is a valid network?\n",
			msg->network->nwid);
	}
	if (msg->eventCode == ZTS_EVENT_NETWORK_REQ_CONFIG) {
		printf("ZTS_EVENT_NETWORK_REQ_CONFIG --- Requesting config for network %llx, please wait a few seconds...\n", msg->network->nwid);
	} 
	if (msg->eventCode == ZTS_EVENT_NETWORK_ACCESS_DENIED) {
		printf("ZTS_EVENT_NETWORK_ACCESS_DENIED --- Access to virtual network %llx has been denied. Did you authorize the node yet?\n",
			msg->network->nwid);
	}
	if (msg->eventCode == ZTS_EVENT_NETWORK_READY_IP4) {
		printf("ZTS_EVENT_NETWORK_READY_IP4 --- Network config received. IPv4 traffic can now be sent over network %llx\n",
			msg->network->nwid);
		networkReady = true;
	}
	if (msg->eventCode == ZTS_EVENT_NETWORK_READY_IP6) {
		printf("ZTS_EVENT_NETWORK_READY_IP6 --- Network config received. IPv6 traffic can now be sent over network %llx\n",
			msg->network->nwid);
		networkReady = true;
	}
	if (msg->eventCode == ZTS_EVENT_NETWORK_DOWN) {
		printf("ZTS_EVENT_NETWORK_DOWN --- %llx\n", msg->network->nwid);
	}

	// Address events
	if (msg->eventCode == ZTS_EVENT_ADDR_ADDED_IP4) {
		char ipstr[ZTS_INET_ADDRSTRLEN];
		struct zts_sockaddr_in *in4 = (struct zts_sockaddr_in*)&(msg->addr->addr);
		zts_inet_ntop(ZTS_AF_INET, &(in4->sin_addr), ipstr, ZTS_INET_ADDRSTRLEN);
		printf("ZTS_EVENT_ADDR_NEW_IP4 --- This node's virtual address on network %llx is %s\n", 
			msg->addr->nwid, ipstr);
	}
	if (msg->eventCode == ZTS_EVENT_ADDR_ADDED_IP6) {
		char ipstr[ZTS_INET6_ADDRSTRLEN];
		struct zts_sockaddr_in6 *in6 = (struct zts_sockaddr_in6*)&(msg->addr->addr);
		zts_inet_ntop(ZTS_AF_INET6, &(in6->sin6_addr), ipstr, ZTS_INET6_ADDRSTRLEN);
		printf("ZTS_EVENT_ADDR_NEW_IP6 --- This node's virtual address on network %llx is %s\n", 
			msg->addr->nwid, ipstr);
	}
	if (msg->eventCode == ZTS_EVENT_ADDR_REMOVED_IP4) {
		char ipstr[ZTS_INET_ADDRSTRLEN];
		struct zts_sockaddr_in *in4 = (struct zts_sockaddr_in*)&(msg->addr->addr);
		zts_inet_ntop(ZTS_AF_INET, &(in4->sin_addr), ipstr, ZTS_INET_ADDRSTRLEN);
		printf("ZTS_EVENT_ADDR_REMOVED_IP4 --- The virtual address %s for this node on network %llx has been removed.\n", 
			ipstr, msg->addr->nwid);
	}
	if (msg->eventCode == ZTS_EVENT_ADDR_REMOVED_IP6) {
		char ipstr[ZTS_INET6_ADDRSTRLEN];
		struct zts_sockaddr_in6 *in6 = (struct zts_sockaddr_in6*)&(msg->addr->addr);
		zts_inet_ntop(ZTS_AF_INET6, &(in6->sin6_addr), ipstr, ZTS_INET6_ADDRSTRLEN);
		printf("ZTS_EVENT_ADDR_REMOVED_IP6 --- The virtual address %s for this node on network %llx has been removed.\n", 
			ipstr, msg->addr->nwid);
	}
	// Peer events
	if (msg->eventCode == ZTS_EVENT_PEER_DIRECT) {
		printf("ZTS_EVENT_PEER_DIRECT --- node=%llx\n", msg->peer->address);
		// A direct path is known for nodeId
	}
	if (msg->eventCode == ZTS_EVENT_PEER_RELAY) {
		printf("ZTS_EVENT_PEER_RELAY --- node=%llx\n", msg->peer->address);
		// No direct path is known for nodeId
	}
}

/**
 *
 *   IDENTITIES and AUTHORIZATION:
 *
 * - Upon the first execution of this code, a new identity will be generated and placed in
 *   the location given in the first argument to zts_start(path, ...). If you accidentally
 *   duplicate the identity files and use them simultaneously in a different node instance
 *   you will experience undefined behavior and it is likely nothing will work.
 * 
 * - You must authorize the node ID provided by the ZTS_EVENT_NODE_ONLINE callback to join
 *   your network, otherwise nothing will happen. This can be done manually or via
 *   our web API: https://my.zerotier.com/help/api
 *
 * - Exceptions to the above rule are:
 *    1) Joining a public network (such as "earth")
 *    2) Joining an Ad-hoc network, (no controller and therefore requires no authorization.)
 *
 *
 *   ESTABLISHING A CONNECTION:
 *
 * - Creating a standard socket connection generally works the same as it would using
 *   an ordinary socket interface, however with libzt there is a subtle difference in
 *   how connections are established which may cause confusion:
 *
 *   The underlying virtual ZT layer creates what are called "transport-triggered links"
 *   between nodes. That is, links are not established until an attempt to communicate
 *   with a peer has taken place. The side effect is that the first few packets sent from
 *   a libzt instance are usually relayed via our free infrastructure and it isn't until a
 *   root server has passed contact information to both peers that a direct connection will be
 *   established. Therefore, it is required that multiple connection attempts be undertaken
 *   when initially communicating with a peer. After a transport-triggered link is
 *   established libzt will inform you via ZTS_EVENT_PEER_DIRECT for a specific peer ID. No
 *   action is required on your part for this callback event.
 *
 *   Note: In these initial moments before ZTS_EVENT_PEER_DIRECT has been received for a
 *         specific peer, traffic may be slow, jittery and there may be high packet loss.
 *         This will subside within a couple of seconds.
 *
 *
 *   ERROR HANDLING:
 *
 * - libzt's API is actually composed of two categories of functions with slightly
 *   different error reporting mechanisms.
 *
 *   Category 1: Control functions (zts_start, zts_join, zts_get_peer_status, etc). Errors
 *                returned by these functions can be any of the following:
 *
 *      ZTS_ERR_OK            0 // No error
 *      ZTS_ERR_SOCKET       -1 // Socket error, see zts_errno
 *      ZTS_ERR_SERVICE      -2 // You probably did something at the wrong time
 *      ZTS_ERR_ARG          -3 // Invalid argument
 *      ZTS_ERR_NO_RESULT    -4 // No result (not necessarily an error)
 *      ZTS_ERR_GENERAL      -5 // Consider filing a bug report
 *
 *   Category 2: Sockets (zts_socket, zts_bind, zts_connect, zts_listen, etc).
 *               Errors returned by these functions can be the same as the above. With
 *               the added possibility of zts_errno being set. Much like standard
 *               errno this will provide a more specific reason for an error's occurrence.
 *               See ZeroTierSockets.h for values.
 *
 *
 *   API COMPATIBILITY WITH HOST OS:
 *
 * - While the ZeroTier socket interface can coexist with your host OS's own interface in
 *   the same file with no type and naming conflicts, try not to mix and match host
 *   OS/libzt structures, functions, or constants. It may look similar and may even work
 *   some of the time but there enough differences that it will cause headaches. Here
 *   are a few guidelines:
 *
 *   If you are calling a zts_* function, use the appropriate ZTS_* constants:
 *             
 *          zts_socket(ZTS_AF_INET6, ZTS_SOCK_DGRAM, 0); (CORRECT)
 *          zts_socket(AF_INET6, SOCK_DGRAM, 0);         (INCORRECT)
 *
 *   If you are calling a zts_* function, use the appropriate zts_* structure:
 *
 *          struct zts_sockaddr_in in4;  <------ Note the zts_* prefix
 *             ...
 *          zts_bind(fd, (struct zts_sockaddr *)&in4, sizeof(struct zts_sockaddr_in)) < 0)
 *
 */

int main(int argc, char **argv) 
{
	if (argc != 6) {
		printf("\nlibzt example client\n");
		printf("client <config_file_path> <nwid> <remoteAddr> <remotePort> <ztServicePort>\n");
		exit(0);
	}
	uint64_t nwid = strtoull(argv[2],NULL,16); // Network ID to join
	std::string remoteAddr = argv[3]; // Remote application's virtual ZT address
	int remotePort = atoi(argv[4]); // Port the application will try to connect to the server on
	int ztServicePort = atoi(argv[5]); // Port ZT uses to send encrypted UDP packets to peers (try something like 9994)

	struct zts_sockaddr_in in4;
	in4.sin_port = zts_htons(remotePort);
#if defined(_WIN32)
	in4.sin_addr.S_addr = zts_inet_addr(remoteAddr.c_str());
#else
	in4.sin_addr.s_addr = zts_inet_addr(remoteAddr.c_str());
#endif
	in4.sin_family = ZTS_AF_INET;

	// Bring up ZeroTier service and join network

	int err = ZTS_ERR_OK;

	if((err = zts_start(argv[1], &myZeroTierEventCallback, ztServicePort)) != ZTS_ERR_OK) {
		printf("Unable to start service, error = %d. Exiting.\n", err);
		exit(1);
	}
	printf("Waiting for node to come online...\n");
	while (!nodeReady) { zts_delay_ms(50); }
	printf("This node's identity is stored in %s\n", argv[1]);

	if((err = zts_join(nwid)) != ZTS_ERR_OK) {
		printf("Unable to join network, error = %d. Exiting.\n", err);
		exit(1);
	}
	printf("Joining network %llx\n", nwid);
	printf("Don't forget to authorize this device in my.zerotier.com or the web API!\n");
	while (!networkReady) { zts_delay_ms(50); }

	// Socket-like API example

	char *msgStr = (char*)"Welcome to the machine";
	int bytes=0, fd;
	char recvBuf[128];
	memset(recvBuf, 0, sizeof(recvBuf));

	if ((fd = zts_socket(ZTS_AF_INET, ZTS_SOCK_STREAM, 0)) < 0) {
		printf("Error creating ZeroTier socket (fd=%d, zts_errno=%d). Exiting.\n", fd, zts_errno);
		exit(1);
	}
	// Retries are often required since ZT uses transport-triggered links (explained above)
	for (;;) {
		printf("Connecting to remote host...\n");
		if ((err = zts_connect(fd, (const struct zts_sockaddr *)&in4, sizeof(in4))) < 0) {
			printf("Error connecting to remote host (fd=%d, ret=%d, zts_errno=%d). Trying again.\n",
				fd, err, zts_errno);
			zts_close(fd);
			printf("Creating socket...\n");
			if ((fd = zts_socket(ZTS_AF_INET, ZTS_SOCK_STREAM, 0)) < 0) {
				printf("Error creating ZeroTier socket (fd=%d, zts_errno=%d). Exiting.\n", fd, zts_errno);
				exit(1);
			}
			zts_delay_ms(250);
		} 
		else {
			printf("Connected.\n");
			break;
		}
	}
	printf("Sending message string to server...\n");
	if((bytes = zts_write(fd, msgStr, strlen(msgStr))) < 0) {
		printf("Error writing to socket (fd=%d, ret=%d, zts_errno=%d). Exiting.\n", fd, bytes, zts_errno);
		exit(1);
	}
	printf("Sent %d bytes: %s\n", bytes, msgStr);
	printf("Reading message string from server...\n");
	if((bytes = zts_read(fd, recvBuf, sizeof(recvBuf))) < 0) {
		printf("Error writing to socket (fd=%d, ret=%d, zts_errno=%d). Exiting.\n", fd, bytes, zts_errno);
		exit(1);
	}
	printf("Read %d bytes: %s\n", bytes, recvBuf);
	printf("Closing socket\n");
	zts_close(fd);
	printf("Shutting down service\n");
	zts_stop();
	return 0;
}