text: // Copyright (c) 2011-2016 The Bitcoin Core developers
  // Distributed under the MIT software license, see the accompanying
  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  #include <qt/recentrequeststablemodel.h>
  
  #include <qt/bitcoinunits.h>
  #include <qt/guiutil.h>
  #include <qt/optionsmodel.h>
  
  #include <clientversion.h>
  #include <streams.h>
  
  RecentRequestsTableModel::RecentRequestsTableModel(WalletModel *parent)
      : QAbstractTableModel(parent), walletModel(parent) {
      nReceiveRequestsMaxId = 0;
  
      // Load entries from wallet
      std::vector<std::string> vReceiveRequests;
      parent->loadReceiveRequests(vReceiveRequests);
      for (const std::string &request : vReceiveRequests) {
          addNewRequest(request);
      }
  
      /* These columns must match the indices in the ColumnIndex enumeration */
      columns << tr("Date") << tr("Label") << tr("Message") << getAmountTitle();
  
      connect(walletModel->getOptionsModel(), SIGNAL(displayUnitChanged(int)),
              this, SLOT(updateDisplayUnit()));
  }
  
  RecentRequestsTableModel::~RecentRequestsTableModel() {
      /* Intentionally left empty */
  }
  
  int RecentRequestsTableModel::rowCount(const QModelIndex &parent) const {
      Q_UNUSED(parent);
  
      return list.length();
  }
  
  int RecentRequestsTableModel::columnCount(const QModelIndex &parent) const {
      Q_UNUSED(parent);
  
      return columns.length();
  }
  
  QVariant RecentRequestsTableModel::data(const QModelIndex &index,
                                          int role) const {
      if (!index.isValid() || index.row() >= list.length()) return QVariant();
  
      if (role == Qt::DisplayRole || role == Qt::EditRole) {
          const RecentRequestEntry *rec = &list[index.row()];
          switch (index.column()) {
              case Date:
                  return GUIUtil::dateTimeStr(rec->date);
              case Label:
                  if (rec->recipient.label.isEmpty() && role == Qt::DisplayRole) {
                      return tr("(no label)");
                  } else {
                      return rec->recipient.label;
                  }
              case Message:
                  if (rec->recipient.message.isEmpty() &&
                      role == Qt::DisplayRole) {
                      return tr("(no message)");
                  } else {
                      return rec->recipient.message;
                  }
              case Amount:
                  if (rec->recipient.amount == ::Amount::zero() &&
                      role == Qt::DisplayRole)
                      return tr("(no amount requested)");
                  else if (role == Qt::EditRole)
                      return BitcoinUnits::format(
                          walletModel->getOptionsModel()->getDisplayUnit(),
                          rec->recipient.amount, false,
                          BitcoinUnits::separatorNever);
                  else
                      return BitcoinUnits::format(
                          walletModel->getOptionsModel()->getDisplayUnit(),
                          rec->recipient.amount);
          }
      } else if (role == Qt::TextAlignmentRole) {
          if (index.column() == Amount)
              return (int)(Qt::AlignRight | Qt::AlignVCenter);
      }
      return QVariant();
  }
  
  bool RecentRequestsTableModel::setData(const QModelIndex &index,
                                         const QVariant &value, int role) {
      return true;
  }
  
  QVariant RecentRequestsTableModel::headerData(int section,
                                                Qt::Orientation orientation,
                                                int role) const {
      if (orientation == Qt::Horizontal) {
          if (role == Qt::DisplayRole && section < columns.size()) {
              return columns[section];
          }
      }
      return QVariant();
  }
  
  /** Updates the column title to "Amount (DisplayUnit)" and emits
   * headerDataChanged() signal for table headers to react. */
  void RecentRequestsTableModel::updateAmountColumnTitle() {
      columns[Amount] = getAmountTitle();
      Q_EMIT headerDataChanged(Qt::Horizontal, Amount, Amount);
  }
  
  /** Gets title for amount column including current display unit if optionsModel
   * reference available. */
  QString RecentRequestsTableModel::getAmountTitle() {
      return (this->walletModel->getOptionsModel() != nullptr)
                 ? tr("Requested") + " (" +
                       BitcoinUnits::name(this->walletModel->getOptionsModel()
                                              ->getDisplayUnit()) +
                       ")"
                 : "";
  }
  
  QModelIndex RecentRequestsTableModel::index(int row, int column,
                                              const QModelIndex &parent) const {
      Q_UNUSED(parent);
  
      return createIndex(row, column);
  }
  
  bool RecentRequestsTableModel::removeRows(int row, int count,
                                            const QModelIndex &parent) {
      Q_UNUSED(parent);
  
      if (count > 0 && row >= 0 && (row + count) <= list.size()) {
          const RecentRequestEntry *rec;
          for (int i = 0; i < count; ++i) {
              rec = &list[row + i];
              if (!walletModel->saveReceiveRequest(
                      rec->recipient.address.toStdString(), rec->id, ""))
                  return false;
          }
  
          beginRemoveRows(parent, row, row + count - 1);
          list.erase(list.begin() + row, list.begin() + row + count);
          endRemoveRows();
          return true;
      } else {
          return false;
      }
  }
  
  Qt::ItemFlags RecentRequestsTableModel::flags(const QModelIndex &index) const {
      return Qt::ItemIsSelectable | Qt::ItemIsEnabled;
  }
  
  // called when adding a request from the GUI
  void RecentRequestsTableModel::addNewRequest(
      const SendCoinsRecipient &recipient) {
      RecentRequestEntry newEntry;
      newEntry.id = ++nReceiveRequestsMaxId;
      newEntry.date = QDateTime::currentDateTime();
      newEntry.recipient = recipient;
  
      CDataStream ss(SER_DISK, CLIENT_VERSION);
      ss << newEntry;
  
      if (!walletModel->saveReceiveRequest(recipient.address.toStdString(),
                                           newEntry.id, ss.str()))
          return;
  
      addNewRequest(newEntry);
  }
  
  // called from ctor when loading from wallet
  void RecentRequestsTableModel::addNewRequest(const std::string &recipient) {
      std::vector<char> data(recipient.begin(), recipient.end());
      CDataStream ss(data, SER_DISK, CLIENT_VERSION);
  
      RecentRequestEntry entry;
      ss >> entry;
  
      // should not happen
      if (entry.id == 0) return;
  
      if (entry.id > nReceiveRequestsMaxId) nReceiveRequestsMaxId = entry.id;
  
      addNewRequest(entry);
  }
  
  // actually add to table in GUI
  void RecentRequestsTableModel::addNewRequest(RecentRequestEntry &recipient) {
      beginInsertRows(QModelIndex(), 0, 0);
      list.prepend(recipient);
      endInsertRows();
  }
  
  void RecentRequestsTableModel::sort(int column, Qt::SortOrder order) {
      qSort(list.begin(), list.end(), RecentRequestEntryLessThan(column, order));
      Q_EMIT dataChanged(
          index(0, 0, QModelIndex()),
          index(list.size() - 1, NUMBER_OF_COLUMNS - 1, QModelIndex()));
  }
  
  void RecentRequestsTableModel::updateDisplayUnit() {
      updateAmountColumnTitle();
  }
  
  bool RecentRequestEntryLessThan::operator()(RecentRequestEntry &left,
                                              RecentRequestEntry &right) const {
      RecentRequestEntry *pLeft = &left;
      RecentRequestEntry *pRight = &right;
      if (order == Qt::DescendingOrder) std::swap(pLeft, pRight);
  
      switch (column) {
          case RecentRequestsTableModel::Date:
              return pLeft->date.toTime_t() < pRight->date.toTime_t();
          case RecentRequestsTableModel::Label:
              return pLeft->recipient.label < pRight->recipient.label;
          case RecentRequestsTableModel::Message:
              return pLeft->recipient.message < pRight->recipient.message;
          case RecentRequestsTableModel::Amount:
              return pLeft->recipient.amount < pRight->recipient.amount;
          default:
              return pLeft->id < pRight->id;
      }
  }
  