// Copyright (c) 2012-2015, The CryptoNote developers, The Bytecoin developers
//
// This file is part of Bytecoin.
//
// Bytecoin is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Bytecoin 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 Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with Bytecoin.  If not, see <http://www.gnu.org/licenses/>.

#include "WalletLegacy.h"

#include <string.h>
#include <time.h>

#include "WalletLegacy/WalletHelper.h"
#include "WalletLegacy/WalletLegacySerialization.h"
#include "WalletLegacy/WalletLegacySerializer.h"
#include "WalletLegacy/WalletUtils.h"

using namespace Crypto;

namespace {

const uint64_t ACCOUN_CREATE_TIME_ACCURACY = 24 * 60 * 60;

void throwNotDefined() {
  throw std::runtime_error("The behavior is not defined!");
}

class ContextCounterHolder
{
public:
  ContextCounterHolder(CryptoNote::WalletAsyncContextCounter& shutdowner) : m_shutdowner(shutdowner) {}
  ~ContextCounterHolder() { m_shutdowner.delAsyncContext(); }

private:
  CryptoNote::WalletAsyncContextCounter& m_shutdowner;
};

template <typename F>
void runAtomic(std::mutex& mutex, F f) {
  std::unique_lock<std::mutex> lock(mutex);
  f();
}

class InitWaiter : public CryptoNote::IWalletLegacyObserver {
public:
  InitWaiter() : future(promise.get_future()) {}

  virtual void initCompleted(std::error_code result) override {
    promise.set_value(result);
  }

  std::error_code waitInit() {
    return future.get();
  }
private:
  std::promise<std::error_code> promise;
  std::future<std::error_code> future;
};


class SaveWaiter : public CryptoNote::IWalletLegacyObserver {
public:
  SaveWaiter() : future(promise.get_future()) {}

  virtual void saveCompleted(std::error_code result) override {
    promise.set_value(result);
  }

  std::error_code waitSave() {
    return future.get();
  }

private:
  std::promise<std::error_code> promise;
  std::future<std::error_code> future;
};

} //namespace

namespace CryptoNote {

class SyncStarter : public CryptoNote::IWalletLegacyObserver {
public:
  SyncStarter(BlockchainSynchronizer& sync) : m_sync(sync) {}
  virtual ~SyncStarter() {}

  virtual void initCompleted(std::error_code result) {
    if (!result) {
      m_sync.start();
    }
  }

  BlockchainSynchronizer& m_sync;
};

WalletLegacy::WalletLegacy(const CryptoNote::Currency& currency, INode& node) :
  m_state(NOT_INITIALIZED),
  m_currency(currency),
  m_node(node),
  m_isStopping(false),
  m_lastNotifiedActualBalance(0),
  m_lastNotifiedPendingBalance(0),
  m_blockchainSync(node, currency.genesisBlockHash()),
  m_transfersSync(currency, m_blockchainSync, node),
  m_transferDetails(nullptr),
  m_sender(nullptr),
  m_onInitSyncStarter(new SyncStarter(m_blockchainSync))
{
  addObserver(m_onInitSyncStarter.get());
}

WalletLegacy::~WalletLegacy() {
  removeObserver(m_onInitSyncStarter.get());

  {
    std::unique_lock<std::mutex> lock(m_cacheMutex);
    if (m_state != NOT_INITIALIZED) {
      m_sender->stop();
      m_isStopping = true;
    }
  }

  m_blockchainSync.removeObserver(this);
  m_blockchainSync.stop();
  m_asyncContextCounter.waitAsyncContextsFinish();
  m_sender.release();
}

void WalletLegacy::addObserver(IWalletLegacyObserver* observer) {
  m_observerManager.add(observer);
}

void WalletLegacy::removeObserver(IWalletLegacyObserver* observer) {
  m_observerManager.remove(observer);
}

void WalletLegacy::initAndGenerate(const std::string& password) {
  {
    std::unique_lock<std::mutex> stateLock(m_cacheMutex);

    if (m_state != NOT_INITIALIZED) {
      throw std::system_error(make_error_code(error::ALREADY_INITIALIZED));
    }

    m_account.generate();
    m_password = password;

    initSync();
  }

  m_observerManager.notify(&IWalletLegacyObserver::initCompleted, std::error_code());
}

void WalletLegacy::initWithKeys(const AccountKeys& accountKeys, const std::string& password) {
  {
    std::unique_lock<std::mutex> stateLock(m_cacheMutex);

    if (m_state != NOT_INITIALIZED) {
      throw std::system_error(make_error_code(error::ALREADY_INITIALIZED));
    }

    m_account.setAccountKeys(accountKeys);
    m_account.set_createtime(ACCOUN_CREATE_TIME_ACCURACY);
    m_password = password;

    initSync();
  }

  m_observerManager.notify(&IWalletLegacyObserver::initCompleted, std::error_code());
}

void WalletLegacy::initAndLoad(std::istream& source, const std::string& password) {
  std::unique_lock<std::mutex> stateLock(m_cacheMutex);

  if (m_state != NOT_INITIALIZED) {
    throw std::system_error(make_error_code(error::ALREADY_INITIALIZED));
  }

  m_password = password;
  m_state = LOADING;
      
  m_asyncContextCounter.addAsyncContext();
  std::thread loader(&WalletLegacy::doLoad, this, std::ref(source));
  loader.detach();
}

void WalletLegacy::initSync() {
  AccountSubscription sub;
  sub.keys = reinterpret_cast<const AccountKeys&>(m_account.getAccountKeys());
  sub.transactionSpendableAge = 1;
  sub.syncStart.height = 0;
  sub.syncStart.timestamp = m_account.get_createtime() - ACCOUN_CREATE_TIME_ACCURACY;
  
  auto& subObject = m_transfersSync.addSubscription(sub);
  m_transferDetails = &subObject.getContainer();
  subObject.addObserver(this);

  m_sender.reset(new WalletTransactionSender(m_currency, m_transactionsCache, m_account.getAccountKeys(), *m_transferDetails));
  m_state = INITIALIZED;
  
  m_blockchainSync.addObserver(this);
}

void WalletLegacy::doLoad(std::istream& source) {
  ContextCounterHolder counterHolder(m_asyncContextCounter);
  try {
    std::unique_lock<std::mutex> lock(m_cacheMutex);
    
    std::string cache;
    WalletLegacySerializer serializer(m_account, m_transactionsCache);
    serializer.deserialize(source, m_password, cache);
      
    initSync();

    try {
      if (!cache.empty()) {
        std::stringstream stream(cache);
        m_transfersSync.load(stream);
      }
    } catch (const std::exception&) {
      // ignore cache loading errors
    }
  } catch (std::system_error& e) {
    runAtomic(m_cacheMutex, [this] () {this->m_state = WalletLegacy::NOT_INITIALIZED;} );
    m_observerManager.notify(&IWalletLegacyObserver::initCompleted, e.code());
    return;
  } catch (std::exception&) {
    runAtomic(m_cacheMutex, [this] () {this->m_state = WalletLegacy::NOT_INITIALIZED;} );
    m_observerManager.notify(&IWalletLegacyObserver::initCompleted, make_error_code(CryptoNote::error::INTERNAL_WALLET_ERROR));
    return;
  }

  m_observerManager.notify(&IWalletLegacyObserver::initCompleted, std::error_code());
}

void WalletLegacy::shutdown() {
  {
    std::unique_lock<std::mutex> lock(m_cacheMutex);

    if (m_isStopping)
      throwNotDefined();

    m_isStopping = true;

    if (m_state != INITIALIZED)
      throwNotDefined();

    m_sender->stop();
  }

  m_blockchainSync.removeObserver(this);
  m_blockchainSync.stop();
  m_asyncContextCounter.waitAsyncContextsFinish();

  m_sender.release();
   
  {
    std::unique_lock<std::mutex> lock(m_cacheMutex);
    m_isStopping = false;
    m_state = NOT_INITIALIZED;

    const auto& accountAddress = m_account.getAccountKeys().address;
    auto subObject = m_transfersSync.getSubscription(accountAddress);
    assert(subObject != nullptr);
    subObject->removeObserver(this);
    m_transfersSync.removeSubscription(accountAddress);
    m_transferDetails = nullptr;

    m_transactionsCache.reset();
    m_lastNotifiedActualBalance = 0;
    m_lastNotifiedPendingBalance = 0;
  }
}

void WalletLegacy::reset() {
  try {
    std::error_code saveError;
    std::stringstream ss;
    {
      SaveWaiter saveWaiter;
      WalletHelper::IWalletRemoveObserverGuard saveGuarantee(*this, saveWaiter);
      save(ss, false, false);
      saveError = saveWaiter.waitSave();
    }

    if (!saveError) {
      shutdown();
      InitWaiter initWaiter;
      WalletHelper::IWalletRemoveObserverGuard initGuarantee(*this, initWaiter);
      initAndLoad(ss, m_password);
      initWaiter.waitInit();
    }
  } catch (std::exception& e) {
    std::cout << "exception in reset: " << e.what() << std::endl;
  }
}

void WalletLegacy::save(std::ostream& destination, bool saveDetailed, bool saveCache) {
  if(m_isStopping) {
    m_observerManager.notify(&IWalletLegacyObserver::saveCompleted, make_error_code(CryptoNote::error::OPERATION_CANCELLED));
    return;
  }

  {
    std::unique_lock<std::mutex> lock(m_cacheMutex);

    throwIf(m_state != INITIALIZED, CryptoNote::error::WRONG_STATE);

    m_state = SAVING;
  }

  m_asyncContextCounter.addAsyncContext();
  std::thread saver(&WalletLegacy::doSave, this, std::ref(destination), saveDetailed, saveCache);
  saver.detach();
}

void WalletLegacy::doSave(std::ostream& destination, bool saveDetailed, bool saveCache) {
  ContextCounterHolder counterHolder(m_asyncContextCounter);

  try {
    m_blockchainSync.stop();
    std::unique_lock<std::mutex> lock(m_cacheMutex);
    
    WalletLegacySerializer serializer(m_account, m_transactionsCache);
    std::string cache;

    if (saveCache) {
      std::stringstream stream;
      m_transfersSync.save(stream);
      cache = stream.str();
    }

    serializer.serialize(destination, m_password, saveDetailed, cache);

    m_state = INITIALIZED;
    m_blockchainSync.start(); //XXX: start can throw. what to do in this case?
    }
  catch (std::system_error& e) {
    runAtomic(m_cacheMutex, [this] () {this->m_state = WalletLegacy::INITIALIZED;} );
    m_observerManager.notify(&IWalletLegacyObserver::saveCompleted, e.code());
    return;
  }
  catch (std::exception&) {
    runAtomic(m_cacheMutex, [this] () {this->m_state = WalletLegacy::INITIALIZED;} );
    m_observerManager.notify(&IWalletLegacyObserver::saveCompleted, make_error_code(CryptoNote::error::INTERNAL_WALLET_ERROR));
    return;
  }

  m_observerManager.notify(&IWalletLegacyObserver::saveCompleted, std::error_code());
}

std::error_code WalletLegacy::changePassword(const std::string& oldPassword, const std::string& newPassword) {
  std::unique_lock<std::mutex> passLock(m_cacheMutex);

  throwIfNotInitialised();

  if (m_password.compare(oldPassword))
    return make_error_code(CryptoNote::error::WRONG_PASSWORD);

  //we don't let the user to change the password while saving
  m_password = newPassword;

  return std::error_code();
}

std::string WalletLegacy::getAddress() {
  std::unique_lock<std::mutex> lock(m_cacheMutex);
  throwIfNotInitialised();

  return m_currency.accountAddressAsString(m_account);
}

uint64_t WalletLegacy::actualBalance() {
  std::unique_lock<std::mutex> lock(m_cacheMutex);
  throwIfNotInitialised();

  return m_transferDetails->balance(ITransfersContainer::IncludeKeyUnlocked) -
    m_transactionsCache.unconfrimedOutsAmount();
}

uint64_t WalletLegacy::pendingBalance() {
  std::unique_lock<std::mutex> lock(m_cacheMutex);
  throwIfNotInitialised();

  uint64_t change = m_transactionsCache.unconfrimedOutsAmount() - m_transactionsCache.unconfirmedTransactionsAmount();
  return m_transferDetails->balance(ITransfersContainer::IncludeKeyNotUnlocked) + change;
}

size_t WalletLegacy::getTransactionCount() {
  std::unique_lock<std::mutex> lock(m_cacheMutex);
  throwIfNotInitialised();

  return m_transactionsCache.getTransactionCount();
}

size_t WalletLegacy::getTransferCount() {
  std::unique_lock<std::mutex> lock(m_cacheMutex);
  throwIfNotInitialised();

  return m_transactionsCache.getTransferCount();
}

TransactionId WalletLegacy::findTransactionByTransferId(TransferId transferId) {
  std::unique_lock<std::mutex> lock(m_cacheMutex);
  throwIfNotInitialised();

  return m_transactionsCache.findTransactionByTransferId(transferId);
}

bool WalletLegacy::getTransaction(TransactionId transactionId, WalletLegacyTransaction& transaction) {
  std::unique_lock<std::mutex> lock(m_cacheMutex);
  throwIfNotInitialised();

  return m_transactionsCache.getTransaction(transactionId, transaction);
}

bool WalletLegacy::getTransfer(TransferId transferId, WalletLegacyTransfer& transfer) {
  std::unique_lock<std::mutex> lock(m_cacheMutex);
  throwIfNotInitialised();

  return m_transactionsCache.getTransfer(transferId, transfer);
}

TransactionId WalletLegacy::sendTransaction(const WalletLegacyTransfer& transfer, uint64_t fee, const std::string& extra, uint64_t mixIn, uint64_t unlockTimestamp) {
  std::vector<WalletLegacyTransfer> transfers;
  transfers.push_back(transfer);
  throwIfNotInitialised();

  return sendTransaction(transfers, fee, extra, mixIn, unlockTimestamp);
}

TransactionId WalletLegacy::sendTransaction(const std::vector<WalletLegacyTransfer>& transfers, uint64_t fee, const std::string& extra, uint64_t mixIn, uint64_t unlockTimestamp) {
  TransactionId txId = 0;
  std::shared_ptr<WalletRequest> request;
  std::deque<std::shared_ptr<WalletLegacyEvent>> events;
  throwIfNotInitialised();

  {
    std::unique_lock<std::mutex> lock(m_cacheMutex);
    request = m_sender->makeSendRequest(txId, events, transfers, fee, extra, mixIn, unlockTimestamp);
  }

  notifyClients(events);

  if (request) {
    m_asyncContextCounter.addAsyncContext();
    request->perform(m_node, std::bind(&WalletLegacy::sendTransactionCallback, this, std::placeholders::_1, std::placeholders::_2));
  }

  return txId;
}

void WalletLegacy::sendTransactionCallback(WalletRequest::Callback callback, std::error_code ec) {
  ContextCounterHolder counterHolder(m_asyncContextCounter);
  std::deque<std::shared_ptr<WalletLegacyEvent> > events;

  boost::optional<std::shared_ptr<WalletRequest> > nextRequest;
  {
    std::unique_lock<std::mutex> lock(m_cacheMutex);
    callback(events, nextRequest, ec);
  }

  notifyClients(events);

  if (nextRequest) {
    m_asyncContextCounter.addAsyncContext();
    (*nextRequest)->perform(m_node, std::bind(&WalletLegacy::synchronizationCallback, this, std::placeholders::_1, std::placeholders::_2));
  }
}

void WalletLegacy::synchronizationCallback(WalletRequest::Callback callback, std::error_code ec) {
  ContextCounterHolder counterHolder(m_asyncContextCounter);

  std::deque<std::shared_ptr<WalletLegacyEvent> > events;
  boost::optional<std::shared_ptr<WalletRequest> > nextRequest;
  {
    std::unique_lock<std::mutex> lock(m_cacheMutex);
    callback(events, nextRequest, ec);
  }

  notifyClients(events);

  if (nextRequest) {
    m_asyncContextCounter.addAsyncContext();
    (*nextRequest)->perform(m_node, std::bind(&WalletLegacy::synchronizationCallback, this, std::placeholders::_1, std::placeholders::_2));
  }
}

std::error_code WalletLegacy::cancelTransaction(size_t transactionId) {
  return make_error_code(CryptoNote::error::TX_CANCEL_IMPOSSIBLE);
}

void WalletLegacy::synchronizationProgressUpdated(uint32_t current, uint32_t total) {
  // forward notification
  m_observerManager.notify(&IWalletLegacyObserver::synchronizationProgressUpdated, current, total);

  // check if balance has changed and notify client
  notifyIfBalanceChanged();
}

void WalletLegacy::synchronizationCompleted(std::error_code result) {
  if (result != std::make_error_code(std::errc::interrupted)) {
    m_observerManager.notify(&IWalletLegacyObserver::synchronizationCompleted, result);
  }

  if (!result) {
    notifyIfBalanceChanged();
  }
}

void WalletLegacy::onTransactionUpdated(ITransfersSubscription* object, const Hash& transactionHash) {
  std::shared_ptr<WalletLegacyEvent> event;

  TransactionInformation txInfo;
  int64_t txBalance;
  if (m_transferDetails->getTransactionInformation(transactionHash, txInfo, txBalance)) {
    std::unique_lock<std::mutex> lock(m_cacheMutex);
    event = m_transactionsCache.onTransactionUpdated(txInfo, txBalance);
  }

  if (event.get()) {
    event->notify(m_observerManager);
  }
}

void WalletLegacy::onTransactionDeleted(ITransfersSubscription* object, const Hash& transactionHash) {
  std::shared_ptr<WalletLegacyEvent> event;

  {
  std::unique_lock<std::mutex> lock(m_cacheMutex);
    event = m_transactionsCache.onTransactionDeleted(transactionHash);
  }

  if (event.get()) {
    event->notify(m_observerManager);
  }
}

void WalletLegacy::throwIfNotInitialised() {
  if (m_state == NOT_INITIALIZED || m_state == LOADING) {
    throw std::system_error(make_error_code(CryptoNote::error::NOT_INITIALIZED));
  }
  assert(m_transferDetails);
}

void WalletLegacy::notifyClients(std::deque<std::shared_ptr<WalletLegacyEvent> >& events) {
  while (!events.empty()) {
    std::shared_ptr<WalletLegacyEvent> event = events.front();
    event->notify(m_observerManager);
    events.pop_front();
  }
}

void WalletLegacy::notifyIfBalanceChanged() {
  auto actual = actualBalance();
  auto prevActual = m_lastNotifiedActualBalance.exchange(actual);

  if (prevActual != actual) {
    m_observerManager.notify(&IWalletLegacyObserver::actualBalanceUpdated, actual);
  }

  auto pending = pendingBalance();
  auto prevPending = m_lastNotifiedPendingBalance.exchange(pending);

  if (prevPending != pending) {
    m_observerManager.notify(&IWalletLegacyObserver::pendingBalanceUpdated, pending);
  }

}

void WalletLegacy::getAccountKeys(AccountKeys& keys) {
  if (m_state == NOT_INITIALIZED) {
    throw std::system_error(make_error_code(CryptoNote::error::NOT_INITIALIZED));
  }

  keys = m_account.getAccountKeys();
}

} //namespace CryptoNote