/**

 * Relational pipes

 * Copyright © 2022 František Kučera (Frantovo.cz, GlobalCode.info)

 *

 * This program is free software: you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation, version 3 of the License.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program. If not, see <http://www.gnu.org/licenses/>.

 */

#include <string>

#include <cstring>

#include <unistd.h>

#include <stdexcept>

#include <arpa/inet.h>

#include <sys/types.h>

#include <sys/socket.h>

#include <netinet/in.h>

#include <vector>

#include <memory>

#include <regex>

#include <iostream>

#include <netdb.h>

#include "Socket.h"

namespace relpipe {

namespace out {

namespace socket {

using namespace relpipe::out::socket::options;

static const std::string findOption(SocketOptions options, std::string name, bool required = false, const std::string defaultValue = "") {

	for (auto o : options) if (o.name == name) return o.value;

	if (required) throw std::invalid_argument("Option " + name + " is required but was not found");

	else return defaultValue;

}

class FD {

private:

	int fd;

public:

	FD(int fd) : fd(fd) {

	};

	virtual ~FD() {

		close(fd);

	}

	int getFD() {

		return fd;

	}

};

static void check(int result, std::string message) {

	if (result == 0); // OK

	else throw std::logic_error("Got error result: " + std::to_string(result) + " - " + message);

}

template <typename T> static T* castAddress(addrinfo* ai, sa_family_t family) {

	if (ai && ai->ai_family == family && sizeof (T) == ai->ai_addrlen) return (T*) ai->ai_addr;

	else return nullptr;

}

static std::string ip2string(const addrinfo* ai) {

	//char buffer[INET_ADDRSTRLEN] = {0};

	char buffer[INET6_ADDRSTRLEN] = {0};

	//return inet_ntop(ai->ai_family, &ai->ai_addr, buffer, sizeof (buffer));

	//return inet_ntop(ai->ai_family, &ai->ai_addr->sa_data, buffer, sizeof (buffer));

	if (ai->ai_family == AF_INET) return inet_ntop(ai->ai_family, &((sockaddr_in const *) ai->ai_addr)->sin_addr, buffer, sizeof (buffer)); // TODO: check 0 result

	else if (ai->ai_family == AF_INET6) return inet_ntop(ai->ai_family, &((sockaddr_in6 const *) ai->ai_addr)->sin6_addr, buffer, sizeof (buffer)); // TODO: check 0 result

	else throw std::logic_error("Invalid address family: " + std::to_string(ai->ai_family));

}

static in_addr_t getAddress(const std::string& host) {

	struct addrinfo query;

	memset(&query, sizeof (query), 0);

	query.ai_socktype = SOCK_STREAM;

	query.ai_protocol = IPPROTO_TCP;

	query.ai_flags = AI_ALL;

	struct addrinfo* addrInfo;

	check(getaddrinfo(host.c_str(), "", &query, &addrInfo), "getaddrinfo");

	std::cerr << "found: " << addrInfo << std::endl;

	if (addrInfo) {

		for (addrinfo* ai = addrInfo; ai; ai = ai->ai_next) {

			std::cerr << "address info: family=" << std::to_string(ai->ai_addr->sa_family) << " socktype=" << std::to_string(ai->ai_socktype) << " protocol=" << std::to_string(ai->ai_protocol);

			if (sockaddr_in * sa = castAddress<sockaddr_in>(ai, AF_INET)) std::cerr << " IPv4=" << ip2string(ai);

			else if (sockaddr_in6 * sa = castAddress<sockaddr_in6>(ai, AF_INET6)) std::cerr << " IPv6=" << ip2string(ai);

			std::cerr << std::endl;

		}

	}

	if (addrInfo) {

		for (addrinfo* ai = addrInfo; ai; ai = ai->ai_next) {

			if (sockaddr_in * sa = castAddress<sockaddr_in>(ai, AF_INET)) {

				in_addr_t address = sa->sin_addr.s_addr;

				freeaddrinfo(addrInfo);

				return address;

			}

		}

	}

	freeaddrinfo(addrInfo);

	// TODO: rather throw exception – requires IP address in the host string:

	return inet_addr(host.c_str());

}

class UDPClientSocket : public Socket {

private:

	struct sockaddr_in remoteAddress;

	int protocol = IPPROTO_UDP;

	int type = SOCK_DGRAM;

public:

	static std::shared_ptr<Socket> open(const SocketOptions& options) {

		std::shared_ptr<UDPClientSocket> s = std::make_shared<UDPClientSocket>();

		memset((char *) &s->remoteAddress, 0, sizeof (s->remoteAddress));

		s->remoteAddress.sin_family = AF_INET;

		s->remoteAddress.sin_addr.s_addr = getAddress(findOption(options, OPTION_HOST, true)); // TODO: use getaddrinfo() instead (because of error -1 = 255.255.255.255)

		s->remoteAddress.sin_port = htons(std::stoi(findOption(options, OPTION_PORT, true)));

		auto protocol = findOption(options, OPTION_PROTOCOL);

		if (protocol == PROTOCOL_SCTP) {

			s->protocol = IPPROTO_SCTP;

			s->type = SOCK_SEQPACKET;

		}

		return s;

	}

	void send(const std::string& message) override {

		FD s(::socket(AF_INET, type, protocol));

		sendto(s.getFD(), message.c_str(), message.size(), 0, (sockaddr*) & remoteAddress, sizeof (remoteAddress));

	}

	const std::string receive() override {

		// TODO: TCP receive()

		return "TODO: receive() a message";

	}

};

class TCPClientSocket : public Socket {

private:

	struct sockaddr_in remoteAddress;

public:

	static std::shared_ptr<Socket> open(const SocketOptions& options) {

		std::shared_ptr<TCPClientSocket> s = std::make_shared<TCPClientSocket>();

		memset((char *) &s->remoteAddress, 0, sizeof (s->remoteAddress));

		s->remoteAddress.sin_family = AF_INET;

		s->remoteAddress.sin_addr.s_addr = getAddress(findOption(options, OPTION_HOST, true).c_str()); // TODO: use getaddrinfo() instead (because of error -1 = 255.255.255.255)

		s->remoteAddress.sin_port = htons(std::stoi(findOption(options, OPTION_PORT, true)));

		return s;

	}

	void send(const std::string& message) override {

		FD s(::socket(AF_INET, SOCK_STREAM, IPPROTO_TCP));

		check(::connect(s.getFD(), (sockaddr*) & remoteAddress, sizeof (remoteAddress)), "connect socket");

		ssize_t written = ::write(s.getFD(), message.c_str(), message.size());

		if (written != message.size()) throw std::logic_error("writing to the socket failed");

	}

	const std::string receive() override {

		// TODO: TCP receive()

		return "TODO: receive() a message";

	}

};

template<const char* protocol, const char* role, const char* mode, typename SocketClass>

class TemplateSocketFactory : public SocketFactory {

public:

	bool canHandle(const SocketOptions& options) override {

		return findOption(options, OPTION_PROTOCOL) == protocol

				&& findOption(options, OPTION_ROLE) == role

				&& findOption(options, OPTION_MODE) == mode;

	}

	std::shared_ptr<Socket> open(const SocketOptions& options) override {

		return SocketClass::open(options);

	}

};

static std::vector<std::shared_ptr<SocketFactory>> factories

{

	std::make_shared<TemplateSocketFactory<PROTOCOL_TCP, ROLE_CLIENT, MODE_STREAM, TCPClientSocket >> (),

			std::make_shared<TemplateSocketFactory<PROTOCOL_TCP, ROLE_SERVER, MODE_STREAM, TCPClientSocket >> (), // TODO: correct class

			std::make_shared<TemplateSocketFactory<PROTOCOL_UDP, ROLE_CLIENT, MODE_DATAGRAM, UDPClientSocket >> (),

			std::make_shared<TemplateSocketFactory<PROTOCOL_UDP, ROLE_SERVER, MODE_DATAGRAM, UDPClientSocket >> (), // TODO: correct class

			std::make_shared<TemplateSocketFactory<PROTOCOL_SCTP, ROLE_CLIENT, MODE_STREAM, UDPClientSocket >> (), // TODO: correct class

			std::make_shared<TemplateSocketFactory<PROTOCOL_SCTP, ROLE_CLIENT, MODE_DATAGRAM, UDPClientSocket >> (), // TODO: correct class

			std::make_shared<TemplateSocketFactory<PROTOCOL_SCTP, ROLE_SERVER, MODE_STREAM, UDPClientSocket >> (), // TODO: correct class

			std::make_shared<TemplateSocketFactory<PROTOCOL_SCTP, ROLE_SERVER, MODE_DATAGRAM, UDPClientSocket >> (), // TODO: correct class

			std::make_shared<TemplateSocketFactory<PROTOCOL_UDS, ROLE_CLIENT, MODE_STREAM, UDPClientSocket >> (), // TODO: correct class

			std::make_shared<TemplateSocketFactory<PROTOCOL_UDS, ROLE_CLIENT, MODE_DATAGRAM, UDPClientSocket >> (), // TODO: correct class

			std::make_shared<TemplateSocketFactory<PROTOCOL_UDS, ROLE_SERVER, MODE_STREAM, UDPClientSocket >> (), // TODO: correct class

			std::make_shared<TemplateSocketFactory<PROTOCOL_UDS, ROLE_SERVER, MODE_DATAGRAM, UDPClientSocket >> (), // TODO: correct class

};

std::shared_ptr<SocketFactory> SocketFactory::find(const SocketOptions& options) {

	for (auto f : factories) if (f->canHandle(options)) return f;

	throw std::logic_error("Unable to find a SocketFactory"); // TODO: add relevant options?

}

}

}

}