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

#define BUF_SIZE 4096

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(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;
}

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

    connection_param = (struct null_connection_params*) ptr;

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

    struct SessionContext session;
    session.insecure_stream = libp2p_net_multistream_stream_new(connection_param->file_descriptor, connection_param->ip, connection_param->port);
    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.insecure_stream)) {

		for(;;) {
			// check if they're looking for an upgrade (i.e. secio)
			unsigned char* results = NULL;
			size_t bytes_read = 0;
			if (!session.default_stream->read(&session, &results, &bytes_read, 5) ) {
				libp2p_logger_debug("null", "stream transaction read returned false\n");
				break;
			}
			if (null_shutting_down) {
				break;
			}
			if (bytes_read == 0) { // timeout
				continue;
			}
			libp2p_logger_debug("null", "Read %lu bytes from a stream tranaction\n", bytes_read);
			if (protocol_compare(results, bytes_read, "/secio")) {
				libp2p_logger_debug("null", "Attempting secure io connection...\n");
				if (!libp2p_secio_handshake(&session, &connection_param->local_node->identity->private_key, 1)) {
					// rejecting connection
					libp2p_logger_debug("null", "Secure IO connection failed\n");
					free(results);
					break;
				}
			} else if (protocol_compare(results, bytes_read, "/nodeio")) {
				libp2p_logger_debug("null", "Attempting a nodeio connection.\n");
				if (!libp2p_nodeio_handshake(&session)) {
					free(results);
					break;
				}
				// 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, 5);
					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(results, bytes_read, "/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");
					free(results);
					break;
				}
				// 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 {
				libp2p_logger_error("null", "There was a problem with this connection. It is nothing I can handle. Disconnecting.\n");
				break;
			}
			free(results);
		}
   	} else {
   		libp2p_logger_log("null", LOGLEVEL_DEBUG, "Multistream negotiation failed\n");
   	}

	if (session.default_stream != NULL) {
		session.default_stream->close(&session);
	}
	if (session.insecure_stream != NULL) {
		libp2p_net_multistream_stream_free(session.insecure_stream);
	}
    (*(connection_param->count))--; // update counter.
    if (connection_param->ip != NULL)
    	free(connection_param->ip);
    free (connection_param);
    return;
}

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) {
        perror("fail to init null router.");
        exit (1);
    }

    libp2p_logger_log("null", LOGLEVEL_ERROR, "Ipfs listening on %d\n", listen_param->port);

    for (;;) {
    	int numDescriptors = socket_read_select4(socketfd, 5);
    	if (null_shutting_down) {
    		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);

    return (void*) 2;
}

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