#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <unistd.h>
#include <pthread.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#include "libp2p/conn/session.h"
#include "libp2p/net/multistream.h"
#include "libp2p/net/p2pnet.h"
#include "libp2p/nodeio/nodeio.h"
#include "libp2p/record/message.h"
#include "libp2p/routing/dht_protocol.h"
#include "libp2p/secio/secio.h"
#include "libp2p/utils/logger.h"
#include "ipfs/core/daemon.h"
#include "ipfs/routing/routing.h"
#include "ipfs/core/ipfs_node.h"
#include "ipfs/merkledag/merkledag.h"
#include "ipfs/merkledag/node.h"
#include "ipfs/util/thread_pool.h"
#include "ipfs/exchange/bitswap/network.h"

#define BUF_SIZE 4096

// this should be set to 5 for normal operation, perhaps higher for debugging purposes
#define DEFAULT_NETWORK_TIMEOUT 5

static int null_shutting_down = 0;

/***
 * Compare incoming to see if they are requesting a protocol upgrade
 * @param incoming the incoming string
 * @param incoming_size the size of the incoming string
 * @param test the protocol string to compare it with (i.e. "/secio" or "/nodeio"
 * @returns true(1) if there was a match, false(0) otherwise
 */
int protocol_compare(const unsigned char* incoming, size_t incoming_size, const char* test) {
	int test_size = strlen(test);
	if (incoming_size >= test_size && strncmp((char*)incoming, test, test_size) == 0)
		return 1;
	return 0;
}

/***
 * Handle the incoming request from a Multistream
 * @param incoming the incoming request
 * @param incoming_size the size of the request in bytes
 * @param session the session context
 * @param connection_param the connection parameters
 * @returns True(1) on success, False(0) on error
 */
int ipfs_null_marshal(const unsigned char* incoming, size_t incoming_size, struct SessionContext* session, struct null_connection_params *connection_param) {
	if (protocol_compare(incoming, incoming_size, "/secio")) {
		libp2p_logger_debug("null", "Attempting secure io connection...\n");
		if (!libp2p_secio_handshake(session, &connection_param->local_node->identity->private_key, connection_param->local_node->peerstore, 1)) {
			// rejecting connection
			libp2p_logger_debug("null", "Secure IO connection failed\n");
			return 0;
		}
		libp2p_logger_debug("null", "Secure IO connection successful.\n");
	} else if (protocol_compare(incoming, incoming_size, "/nodeio")) {
		libp2p_logger_debug("null", "Attempting a nodeio connection.\n");
		if (!libp2p_nodeio_handshake(session)) {
			return 0;
		}
		// loop through file requests
		int _continue = 1;
		while(_continue) {
			unsigned char* hash;
			size_t hash_length = 0;
			_continue = session->default_stream->read(session, &hash, &hash_length, DEFAULT_NETWORK_TIMEOUT);
			if (hash_length < 20) {
				_continue = 0;
				continue;
			}
			else {
				// try to get the Node
				struct HashtableNode* node = NULL;
				if (!ipfs_merkledag_get(hash, hash_length, &node, connection_param->local_node->repo)) {
					_continue = 0;
					continue;
				}
				size_t results_size = ipfs_hashtable_node_protobuf_encode_size(node);
				unsigned char results[results_size];
				if (!ipfs_hashtable_node_protobuf_encode(node, results, results_size, &results_size)) {
					_continue = 0;
					continue;
				}
				// send it to the requestor
				session->default_stream->write(session, results, results_size);
			}
		}
	} else if (protocol_compare(incoming, incoming_size, "/ipfs/kad/")) {
		libp2p_logger_log("null", LOGLEVEL_DEBUG, "Attempting kademlia connection...\n");
		if (!libp2p_routing_dht_handshake(session)) {
			libp2p_logger_log("null", LOGLEVEL_DEBUG, "kademlia connection handshake failed\n");
			return 0;
		}
		// this handles 1 transaction
		libp2p_routing_dht_handle_message(session, connection_param->local_node->peerstore, connection_param->local_node->providerstore);
		libp2p_logger_log("null", LOGLEVEL_DEBUG, "kademlia message handled\n");
	} else if (protocol_compare(incoming, incoming_size, "/ipfs/bitswap/")) {
		libp2p_logger_debug("null", "Attempting bitswap connection...\n");
		return ipfs_bitswap_network_handle_message(connection_param->local_node, session, incoming, incoming_size);
	}
	else {
		libp2p_logger_error("null", "There was a problem with this connection. It is nothing I can handle. Disconnecting.\n");
		return 0;
	}
	return 1;
}

/**
 * We've received a connection. Find out what they want.
 *
 * @param ptr a pointer to a null_connection_params struct
 */
void ipfs_null_connection (void *ptr)
{
    struct null_connection_params *connection_param = (struct null_connection_params*) ptr;

    // TODO: when should we exit the for loop and disconnect?

    struct SessionContext* session = libp2p_session_context_new();
    if (session == NULL) {
    	libp2p_logger_error("null", "Unable to allocate SessionContext. Out of memory?\n");
    	return;
    }

    session->insecure_stream = libp2p_net_multistream_stream_new(connection_param->file_descriptor, connection_param->ip, connection_param->port);

    libp2p_logger_debug("null", "%s null has a file descriptor of %d\n", connection_param->local_node->identity->peer->id, *((int*)session->insecure_stream->socket_descriptor) );

    session->default_stream = session->insecure_stream;
    session->datastore = connection_param->local_node->repo->config->datastore;
    session->filestore = connection_param->local_node->repo->config->filestore;

    libp2p_logger_log("null", LOGLEVEL_INFO, "Connection %d, count %d\n", connection_param->file_descriptor, *(connection_param->count));

	if (libp2p_net_multistream_negotiate(session)) {
		// Someone has connected and successfully negotiated multistream. Now talk to them...
		int unsuccessful_max = 30;
		int unsuccessful_counter = 0;
		for(;;) {
			// Wait for them to ask something...
			unsigned char* results = NULL;
			size_t bytes_read = 0;
			if (null_shutting_down) {
				libp2p_logger_debug("null", "%s null shutting down before read.\n", connection_param->local_node->identity->peer->id);
				// this service is shutting down. Ignore the request and exit the loop
				break;
			}
			if (!session->default_stream->read(session, &results, &bytes_read, DEFAULT_NETWORK_TIMEOUT) ) {
				// the read was unsuccessful wait a sec
				sleep(1);
				unsuccessful_counter++;
				if (unsuccessful_counter >= unsuccessful_max)
					break;
				continue;
			}
			if (null_shutting_down) {
				libp2p_logger_debug("null", "%s null shutting down after read.\n", connection_param->local_node->identity->peer->id);
				// this service is shutting down. Ignore the request and exit the loop
				break;
			}
			if (bytes_read == 0) {
				// They did not ask for anything. There was a timeout. Wait again.
				continue;
			}

			// We actually got something. Process the request...
			unsuccessful_counter = 0;
			libp2p_logger_debug("null", "Read %lu bytes from a stream tranaction\n", bytes_read);
			int retVal = ipfs_null_marshal(results, bytes_read, session, connection_param);
			free(results);
			if (!retVal) {
				libp2p_logger_debug("null", "ipfs_null_marshal returned false\n");
				break;
			}
		}
   	} else {
   		libp2p_logger_log("null", LOGLEVEL_DEBUG, "Multistream negotiation failed\n");
   	}

    libp2p_logger_debug("null", "%s Freeing session context.\n", connection_param->local_node->identity->peer->id);
    (*(connection_param->count))--; // update counter.
    if (connection_param->ip != NULL)
    	free(connection_param->ip);
    free (connection_param);
    libp2p_session_context_free(session);
    return;
}

/***
 * Called by the daemon to listen for connections
 * @param ptr a pointer to an IpfsNodeListenParams struct
 * @returns nothing useful.
 */
void* ipfs_null_listen (void *ptr)
{
    int socketfd, s, count = 0;
    threadpool thpool = thpool_init(25);
    struct IpfsNodeListenParams *listen_param;
    struct null_connection_params *connection_param;

    listen_param = (struct IpfsNodeListenParams*) ptr;

    if ((socketfd = socket_listen(socket_tcp4(), &(listen_param->ipv4), &(listen_param->port))) <= 0) {
        libp2p_logger_error("null", "Failed to init null router. Address: %d, Port: %d\n", listen_param->ipv4, listen_param->port);
        return (void*) 2;
    }

    libp2p_logger_error("null", "Ipfs listening on %d\n", listen_param->port);

    for (;;) {
    	libp2p_logger_debug("null", "%s Attempting socket read\n", listen_param->local_node->identity->peer->id);
    	int numDescriptors = socket_read_select4(socketfd, 2);
    	if (null_shutting_down) {
    		libp2p_logger_debug("null", "%s null_listen shutting down.\n", listen_param->local_node->identity->peer->id);
    		break;
    	}
    	if (numDescriptors > 0) {
			s = socket_accept4(socketfd, &(listen_param->ipv4), &(listen_param->port));
			if (count >= CONNECTIONS) { // limit reached.
				close (s);
				continue;
			}

			count++;
			connection_param = malloc (sizeof (struct null_connection_params));
			if (connection_param) {
				connection_param->file_descriptor = s;
				connection_param->count = &count;
				connection_param->local_node = listen_param->local_node;
				connection_param->port = listen_param->port;
				connection_param->ip = malloc(INET_ADDRSTRLEN);
				if (inet_ntop(AF_INET, &(listen_param->ipv4), connection_param->ip, INET_ADDRSTRLEN) == NULL) {
					free(connection_param->ip);
					connection_param->ip = NULL;
					connection_param->port = 0;
				}
				// Create pthread for ipfs_null_connection.
				thpool_add_work(thpool, ipfs_null_connection, connection_param);
			}
    	}
    }

    thpool_destroy(thpool);

    close(socketfd);

    return (void*) 2;
}

int ipfs_null_shutdown() {
	null_shutting_down = 1;
	return 1;
}