SilentDragon/src/turnstile.cpp

#include "turnstile.h"
#include "rpc.h"
#include "utils.h"
#include "settings.h"

#include "precompiled.h"

using json = nlohmann::json;

Turnstile::Turnstile(RPC* _rpc) {
	this->rpc = _rpc;
}

Turnstile::~Turnstile() {
}

QString Turnstile::writeableFile() {
    auto filename = QStringLiteral("turnstilemigrationplan.dat");

    auto dir = QDir(QStandardPaths::writableLocation(QStandardPaths::AppDataLocation));
    if (!dir.exists())
        QDir().mkpath(dir.absolutePath());

    if (Settings::getInstance()->isTestnet()) {
        return dir.filePath("testnet-" % filename);
    } else {
        return dir.filePath(filename);
    }
}

// Data stream write/read methods for migration items
QDataStream &operator<<(QDataStream& ds, const TurnstileMigrationItem& item) {
	return ds << "v1" << item.fromAddr << item.intTAddr 
	   		  << item.destAddr << item.amount << item.blockNumber << item.chaff;
}

QDataStream &operator>>(QDataStream& ds, TurnstileMigrationItem& item) {
	QString version;
	return ds >> version >> item.fromAddr >> item.intTAddr 
	   		  >> item.destAddr >> item.amount >> item.blockNumber >> item.chaff;
}

void Turnstile::writeMigrationPlan(QList<TurnstileMigrationItem> plan) {
	QFile file(writeableFile());
	file.open(QIODevice::WriteOnly);
	QDataStream out(&file);   // we will serialize the data into the file
	out << plan;
}

QList<TurnstileMigrationItem> Turnstile::readMigrationPlan() {
	QFile file(writeableFile());
	
	QList<TurnstileMigrationItem> plan;
	if (!file.exists()) return plan;

	file.open(QIODevice::ReadOnly);
	QDataStream in(&file);    // read the data serialized from the file
	in >> plan; 

	return plan;
}

void Turnstile::planMigration(QString zaddr, QString destAddr) {
	// First, get the balance and split up the amounts
	auto bal = rpc->getAllBalances()->value(zaddr);
	auto splits = splitAmount(bal+2354, 5);

	// Then, generate an intermediate t-Address for each part using getBatchRPC
	rpc->getBatchRPC<double>(splits,
		[=] (double /*unused*/) {
			json payload = {
				{"jsonrpc", "1.0"},
				{"id", "someid"},
				{"method", "getnewaddress"},
			};
			return payload;
		},
		[=] (QMap<double, json>* newAddrs) {
			// Get block numbers
			auto curBlock = Settings::getInstance()->getBlockNumber();
			auto blockNumbers = getBlockNumbers(curBlock, curBlock + 10, splits.size());

			// Assign the amounts to the addresses.
			QList<TurnstileMigrationItem> migItems;
			
			for (int i=0; i < splits.size(); i++) {
				auto tAddr = newAddrs->values()[i].get<json::string_t>();
				auto item = TurnstileMigrationItem { zaddr, QString::fromStdString(tAddr), destAddr,
													 blockNumbers[i], splits[i], i == splits.size() -1 };
				migItems.push_back(item);
			}

			std::sort(migItems.begin(), migItems.end(), [&] (auto a, auto b) {
				return a.blockNumber < b.blockNumber;
			});		

			// The first migration is shifted to the current block, so the user sees something 
			// happening immediately
			migItems[0].blockNumber = curBlock;

			writeMigrationPlan(migItems);
			auto readPlan = readMigrationPlan();

			for (auto item : readPlan) {
				qDebug() << item.fromAddr << item.intTAddr 
						 << item.destAddr << item.amount << item.blockNumber << item.chaff;
			}
		}
	);
}

QList<int> Turnstile::getBlockNumbers(int start, int end, int count) {
	QList<int> blocks;
	// Generate 'count' numbers between [start, end]
	for (int i=0; i < count; i++) {
		auto blk = (std::rand() % (end - start)) + start;
		blocks.push_back(blk);
	}

	return blocks;
}

QList<double> Turnstile::splitAmount(double amount, int parts) {
	QList<double> amounts;
	// Need at least 0.0004 ZEC for this
	if (amount < 0.0004)
		return amounts;
	
	fillAmounts(amounts, amount, parts);

	// Ensure they all add up!
	double sumofparts = 0;
	for (auto a : amounts) {
		sumofparts += a;
	}

	Q_ASSERT(sumofparts == amount);
	return amounts;
}

void Turnstile::fillAmounts(QList<double>& amounts, double amount, int count) {
	if (count == 1 || amount < 1) {
		// Split the chaff.
		// Chaff is all amounts lesser than 0.0001 ZEC. The chaff will be added to the 
		// dev fee, and is done so to protect privacy.

		// Get the rounded value to 4 decimal places (approx $0.01)
		double actual = std::floor(amount * 10000) / 10000;

		// Reduce the Dev Tx fee from the amount
		actual = actual - 0.0001; //Utils::getDevFee();

		// Also account for the fees needed to send all these transactions
		actual = actual - (Utils::getMinerFee() * (amounts.size() + 1));

		// Calculate the chaff. 
		double chaff  = amount - actual;

		amounts.push_back(actual);
		if (chaff > 0.00000001)	// zcash is split down to 8 decimal places
			amounts.push_back(chaff);
		return;
	}

	// Get a random amount off the amount (between half and full) and call recursively.
	auto curAmount = std::rand() % (int)std::floor(amount);

	// Try to round it off
	if (curAmount > 1000) {
		curAmount = std::floor(curAmount / 100) * 100;
	} else if (curAmount > 100) {
		curAmount = std::floor(curAmount / 10) * 10;
	}

	if (curAmount > 0)
		amounts.push_back(curAmount);

	fillAmounts(amounts, amount - curAmount, count - 1);
}