/**
 * 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));
}

class AddressInfos {
private:
	struct addrinfo* addrInfo;

	AddressInfos(addrinfo* addrInfo) : addrInfo(addrInfo) {
		std::cerr << "  AddressInfo()" << std::endl;
	}

public:

	virtual ~AddressInfos() {
		std::cerr << " ~AddressInfo()" << std::endl;
		freeaddrinfo(addrInfo);
	}
	
	class AddressInfo {
	public:
		const addrinfo* const ai;
		
		AddressInfo(const addrinfo* const ai) : ai(ai) {}
	};

	static AddressInfos getAddressInfo(const std::string& host, const std::string& port) {
		struct addrinfo query;
		memset(&query, sizeof (query), 0);
		query.ai_family = AF_UNSPEC;
		query.ai_socktype = SOCK_STREAM;
		query.ai_protocol = IPPROTO_TCP;
		query.ai_flags = AI_ALL;

		struct addrinfo* addrInfo;
		check(getaddrinfo(host.c_str(), port.c_str(), &query, &addrInfo), "getaddrinfo");

		return AddressInfos(addrInfo);
	}

	const sockaddr* getSocketAddress() {
		return addrInfo->ai_addr;
	}

	const std::size_t size() const {
		std::size_t size = 0;
		for (addrinfo* ai = addrInfo; ai; ai = ai->ai_next) size++;
		return size;
	}

	const addrinfo& operator[](std::size_t index) const {
		for (addrinfo* ai = addrInfo; ai; index--) {
			if (index == 0) return *ai;
			else ai = ai->ai_next;
		}
		
		throw std::out_of_range("invalid index for AddressInfo: " + std::to_string(index));
	}
	
};

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

	{
		AddressInfos ai = AddressInfos::getAddressInfo("::0ff2", "smtp");
		std::cerr << "AddressInfo size = " << ai.size() << std::endl;
		for (size_t i = 0, limit = ai.size(); i < limit; i++) {
			std::cerr << "AddressInfo: " << ip2string(&ai[i]) << std::endl;
		}
	}




	struct addrinfo query;
	memset(&query, sizeof (query), 0);
	query.ai_family = AF_UNSPEC;
	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?
}


}
}
}