#include <netinet/tcp.h>
#include <log/LogUtils.h>
#include <misc/memtracker.h>
#include "crypt.h"
#define DEFINE_HELPER
#include "LicenseRequest.h"
#include "License.h"
#include <csignal>

using namespace std;
using namespace std::chrono;
using namespace ts;
using namespace license;

#define DEBUG_LICENSE_CLIENT
#define CERR(message) LICENSE_FERR(this, CouldNotConnectException, message)


LicenceRequest::LicenceRequest(const std::shared_ptr<LicenseRequestData> & license, const sockaddr_in& remoteAddr) : data(license) {
#ifdef DEBUG_LICENSE_CLIENT
    memtrack::allocated<LicenceRequest>(this);
#endif
    memcpy(&this->remote_address, &remoteAddr, sizeof(remoteAddr));

    assert(license->info);
}

LicenceRequest::~LicenceRequest() {
#ifdef DEBUG_LICENSE_CLIENT
    memtrack::freed<LicenceRequest>(this);
#endif
    this->abortRequest();

    if(this->closeThread) {
        this->closeThread->join();
        delete this->closeThread;
        this->closeThread = nullptr;
    }


	delete this->currentFuture;
	this->currentFuture = nullptr;
}

threads::Future<std::shared_ptr<LicenseRequestResponse>> LicenceRequest::requestInfo() {
    {
        lock_guard lock(this->lock);
        if(this->currentFuture) return *this->currentFuture;
        this->currentFuture = new threads::Future<std::shared_ptr<LicenseRequestResponse>>();
    }

    this->beginRequest();
    return *this->currentFuture;
}


//Basic IO
void LicenceRequest::handleEventWrite(int fd, short event, void* ptrClient) {
    auto* client = static_cast<LicenceRequest *>(ptrClient);

    buffer::RawBuffer* buffer = nullptr;
    {
	    lock_guard lock(client->lock);
        if((event & EV_TIMEOUT) > 0) { //Connect timeout
	        LICENSE_FERR(client, ConnectionException, "Connect timeout");
        	return;
        }

	    if(client->state == protocol::CONNECTING){
		    client->handleConnected();
	    }

	    if(client->state == protocol::UNCONNECTED || !client->event_write)
		    return;

        buffer = TAILQ_FIRST(&client->writeQueue);
        if(!buffer) return;

        auto writtenBytes = send(fd, &buffer->buffer[buffer->index], buffer->length - buffer->index, MSG_NOSIGNAL | MSG_DONTWAIT);
        buffer->index += writtenBytes;

        if(buffer->index >= buffer->length) {
            TAILQ_REMOVE(&client->writeQueue, buffer, tail);
            delete buffer;
        }
        if(!TAILQ_EMPTY(&client->writeQueue))
            event_add(client->event_write, nullptr);
    }
}

void LicenceRequest::sendPacket(const protocol::packet& packet) {
	if(this->state == protocol::UNCONNECTED || this->state == protocol::DISCONNECTING) {
		if(this->verbose)
			logError("Tried to send a packet to an unconnected remote!");
		return;
	}
    packet.prepare();

    auto buffer = new buffer::RawBuffer(packet.data.length() + sizeof(packet.header));
    memcpy(buffer->buffer, &packet.header, sizeof(packet.header));
    memcpy(&buffer->buffer[sizeof(packet.header)], packet.data.data(), packet.data.length());

    if(!this->cryptKey.empty())
        xorBuffer(&buffer->buffer[sizeof(packet.header)], packet.data.length(), this->cryptKey.data(), this->cryptKey.length());

    {
	    lock_guard lock(this->lock);
        TAILQ_INSERT_TAIL(&this->writeQueue, buffer, tail);
        if(this->event_write)
	        event_add(this->event_write, nullptr);
    }
}

void LicenceRequest::handleEventRead(int fd, short, void* ptrClient) {
    auto* client = static_cast<LicenceRequest *>(ptrClient);

	auto buffer = std::unique_ptr<void, decltype(free)*>{malloc(1024), free};
    sockaddr_in remoteAddr{};
    socklen_t remoteAddrSize = sizeof(remoteAddr);

    auto read = recvfrom(fd, buffer.get(), 1024, MSG_NOSIGNAL | MSG_DONTWAIT, reinterpret_cast<sockaddr *>(&remoteAddr), &remoteAddrSize);

    if(read < 0){
        if(errno == EWOULDBLOCK) return;
	    if(client->event_read)
		    event_del_noblock(client->event_read);
        LICENSE_FERR(client, ConnectionException, "Invalid read: " + string(strerror(errno)) + "/" + to_string(errno));
	    return;
    } else if(read == 0) {
    	if(client->event_read)
    	    event_del_noblock(client->event_read);
	    LICENSE_FERR(client, ConnectionException, "IO error (" + to_string(errno) + "): " + string(strerror(errno)));
	    return;
    }

    client->handleMessage(string((char*) buffer.get(), read));
}


static int enabled = 1;
static int disabled = 0;
void LicenceRequest::beginRequest() {
	lock_guard lock(this->lock);
	TAILQ_INIT(&this->writeQueue);

    this->file_descriptor = socket(AF_INET, SOCK_STREAM | SOCK_NONBLOCK, 0);
    if(this->file_descriptor < 0) CERR("Socket setup failed");

	signal(SIGPIPE, SIG_IGN);

	auto state = ::connect(this->file_descriptor, reinterpret_cast<const sockaddr *>(&this->remote_address), sizeof(this->remote_address));
    if(state < 0 && errno != EINPROGRESS) CERR("connect() failed (" + string(strerror(errno)) + ")");

    if(setsockopt(this->file_descriptor, SOL_SOCKET, SO_REUSEADDR, &enabled, sizeof(enabled)) < 0) CERR("could not set reuse addr");
    if(setsockopt(this->file_descriptor, IPPROTO_TCP, TCP_CORK, &disabled, sizeof(disabled)) < 0) CERR("could not set no push");

    if(fcntl(this->file_descriptor, F_SETFD, fcntl(this->file_descriptor, F_GETFL, 0)  | FD_CLOEXEC | O_NONBLOCK) < 0) CERR("Failed to set FD_CLOEXEC and O_NONBLOCK");

    this->event_base = event_base_new();
    this->event_read = event_new(this->event_base, this->file_descriptor, EV_READ | EV_PERSIST, LicenceRequest::handleEventRead, this);
    this->event_write = event_new(this->event_base, this->file_descriptor, EV_WRITE, LicenceRequest::handleEventWrite, this);

	this->state = protocol::CONNECTING; //First set connected, then we could enable the event loop

    event_dispatch = std::thread([&]() {
        signal(SIGPIPE, SIG_IGN);

	    { /* now we could start listening */
	    	lock_guard _lock(this->lock);
	    	if(!this->event_read || !this->event_write) return;

		    event_add(this->event_read, nullptr);
		    timeval connect_timeout{5, 0};
		    event_add(this->event_write, &connect_timeout);
	    }

	    event_base_dispatch(this->event_base);
    });
}

void LicenceRequest::handleConnected() {
	this->state = protocol::HANDSCAKE;

	uint8_t handshakeBuffer[4];
	handshakeBuffer[0] = 0xC0;
	handshakeBuffer[1] = 0xFF;
	handshakeBuffer[2] = 0xEE;
	handshakeBuffer[3] = LICENSE_PROT_VERSION;
	this->sendPacket(protocol::packet{protocol::PACKET_CLIENT_HANDSHAKE, string((const char*) handshakeBuffer, 4)}); //Initialise packet
}

void LicenceRequest::handleMessage(const std::string& message) {
	this->buffer += message;
    if(this->buffer.length() < sizeof(protocol::packet::header))
    	return;

    protocol::packet packet{protocol::PACKET_DISCONNECT, ""};
    memcpy(&packet.header,  this->buffer.data(), sizeof(protocol::packet::header));
    if(packet.header.length <= this->buffer.length() - sizeof(protocol::packet::header)) {
	    packet.data = this->buffer.substr(sizeof(protocol::packet::header), packet.header.length);
	    this->buffer = this->buffer.substr(sizeof(protocol::packet::header) + packet.header.length);
    } else {
    	return;
    }

    if(!this->cryptKey.empty()) {
        xorBuffer((char*) packet.data.data(), packet.data.length(), this->cryptKey.data(), this->cryptKey.length());
    }

	if(packet.header.packetId == protocol::PACKET_SERVER_HANDSHAKE) {
        this->handlePacketHandshake(packet.data);
	} else if(packet.header.packetId == protocol::PACKET_DISCONNECT) {
        this->handlePacketDisconnect(packet.data);
	} else if(packet.header.packetId == protocol::PACKET_SERVER_VALIDATION_RESPONSE) {
        this->handlePacketLicenseInfo(packet.data);
	} else if(packet.header.packetId == protocol::PACKET_SERVER_PROPERTY_ADJUSTMENT) {
        this->handlePacketInfoAdjustment(packet.data);
    } else
		LICENSE_FERR(this, ConnectionException, "Invalid packet id (" + to_string(packet.header.packetId) + ")");

	if(!this->buffer.empty() && this->state != protocol::DISCONNECTING && this->state != protocol::UNCONNECTED)
		this->handleMessage("");
}

void LicenceRequest::disconnect(const std::string& message) {
	if(this->state != protocol::UNCONNECTED && this->state != protocol::DISCONNECTING)
		this->sendPacket({protocol::PACKET_DISCONNECT, message});
	this->closeConnection();
	//TODO flush?
}

void LicenceRequest::closeConnection() {
	event *event_read, *event_write;
    {
        lock_guard lock(this->lock);
        if(this->state == protocol::UNCONNECTED) return;

        if(this->event_dispatch.get_id() == this_thread::get_id()) { //We could not close in the same thread as we read/write (we're joining it later)
            if(this->state == protocol::DISCONNECTING) return;

            this->state = protocol::DISCONNECTING;
            this->closeThread = new threads::Thread(THREAD_SAVE_OPERATIONS, [&]() { this->closeConnection(); });

#ifdef DEBUG_LICENSE_CLIENT
	        if(this->verbose) {
		        debugMessage("Running close in a new thread");
		        this->closeThread->name("License request close");
	        }
#endif
            return;
        }
        this->state = protocol::UNCONNECTED;

	    event_read = this->event_read;
	    event_write = this->event_write;

	    this->event_write = nullptr;
	    this->event_read = nullptr;
    }

    if(event_read) {
        event_del_block(event_read);
        event_free(event_read);
    }

    if(event_write) {
	    event_del_block(event_write);
	    event_free(event_write);
    }

    /* close before base shutdown (else epoll hangup) */
	if(this->file_descriptor > 0) {
		shutdown(this->file_descriptor, SHUT_RDWR);
		close(this->file_descriptor);
	}
	this->file_descriptor = 0;

    {
	    lock_guard lock(this->lock);
        ts::buffer::RawBuffer* buffer;
        while ((buffer = TAILQ_FIRST(&this->writeQueue))) {
            TAILQ_REMOVE(&this->writeQueue, buffer, tail);
            delete buffer;
        }
    }

	{
		if(this->event_base) {
			timeval seconds{1, 0};
			event_base_loopexit(this->event_base, &seconds);
			event_base_loopexit(this->event_base, nullptr);
		}

		if(this->event_dispatch.joinable()) {
			this->event_dispatch.join();
		}

		if(this->event_base) {
			event_base_free(this->event_base);
			this->event_base = nullptr;
		}
	}

#ifdef DEBUG_LICENSE_CLIENT
	if(this->verbose)
	    debugMessage("Executing close done");
#endif
}

void LicenceRequest::abortRequest(const std::chrono::system_clock::time_point &timeout) {
	this->closeConnection();
}