On sending (posting) item to the server the generated UUID is added to the local item.

model/commands/edititemcommand.cpp

@@ -26,6 +26,11 @@ EditItemCommand::EditItemCommand(TableModel* model,
                         .arg(roleName)
                         .arg(index.data(DEFAULT_ROLE).toString())
                         .arg(value.toString());
+    } else if (role == IdRole) {
+      commandText = QString("Setting '%1' of item '%2' to '%3'")
+                        .arg(roleName)
+                        .arg(index.data(DEFAULT_ROLE).toString())
+                        .arg(value.toString());
     } else {
       qWarning() << "Role didn't match! Using a generic command text...";
       commandText = QString("Edit item '%1'").arg(index.data(DEFAULT_ROLE).toString());

model/commands/insertrowscommand.h

@@ -3,7 +3,7 @@
 
 #include <QUndoCommand>
 
-typedef QHash<int, QVariant> ModelItemValues;
+typedef QMap<int, QVariant> ModelItemValues;
 
 class TableModel;
 

model/commands/removerowscommand.h

@@ -5,7 +5,7 @@
 
 class TableModel;
 
-typedef QHash<int, QVariant> ModelItemValues;
+typedef QMap<int, QVariant> ModelItemValues;
 
 class RemoveRowsCommand : public QUndoCommand {
  public:

model/metadata.h

@@ -35,10 +35,11 @@ static QList<UserRoles> INT_ROLES    = {AmountRole};
 static QList<UserRoles> DOUBLE_ROLES = {FactorRole};
 
 /// JSON keys
-static const QString ITEM_KEY_STRING = "items";
+static const QString ITEMS_KEY_STRING = "items";
+static const QString ITEM_KEY_STRING  = "item";
 
 /// file naming
-static const QString ITEM_FILE_NAME = ITEM_KEY_STRING + ".json";
+static const QString ITEMS_FILE_NAME = ITEMS_KEY_STRING + ".json";
 
 /// functions
 static int GET_ROLE_FOR_COLUMN(const int column) {

model/modelitem.h

@@ -3,7 +3,7 @@
 
 #include <QVariant>
 
-typedef QHash<int, QVariant> ModelItemValues;
+typedef QMap<int, QVariant> ModelItemValues;
 
 class ModelItem {
  public:
@@ -18,7 +18,7 @@ class ModelItem {
   QJsonObject toJsonObject() const;
 
  private:
-  QHash<int, QVariant> m_values;
+  ModelItemValues m_values;
 };
 
 #endif  // MODELITEM_H

model/tablemodel.cpp

@@ -29,7 +29,7 @@ QByteArray TableModel::generateExampleItems() {
 
     array.append(itemObject);
   }
-  rootObject.insert(ITEM_KEY_STRING, array);
+  rootObject.insert(ITEMS_KEY_STRING, array);
 
   doc.setObject(rootObject);
   return doc.toJson();
@@ -83,6 +83,7 @@ QVariant TableModel::data(const QModelIndex& index, int role) const {
     case InfoRole:
     case AmountRole:
     case FactorRole:
+    case IdRole:
       return m_items.at(row)->data(role);
     case ToStringRole:
       return m_items.at(row)->toString();
@@ -152,7 +153,7 @@ QJsonDocument TableModel::getAllItemsAsJsonDoc() const {
     QJsonObject itemObject = item->toJsonObject();
     array.append(itemObject);
   }
-  rootObject.insert(ITEM_KEY_STRING, array);
+  rootObject.insert(ITEMS_KEY_STRING, array);
 
   doc.setObject(rootObject);
   return doc;
@@ -175,11 +176,37 @@ QList<QStringList> TableModel::getItemsAsStringLists() const {
 QByteArray TableModel::jsonDataForServer(const QModelIndex& currentIndex) const {
   const QJsonObject itemObject = data(currentIndex, ToJsonRole).toJsonObject();
   QJsonObject rootObject;
-  rootObject.insert("item", itemObject);
+  rootObject.insert(ITEM_KEY_STRING, itemObject);
   const QJsonDocument jsonDoc(rootObject);
   return jsonDoc.toJson(QJsonDocument::Compact);
 }
 
+QString TableModel::updateItemsFromJson(const QByteArray& jsonData) {
+  /// convert JSON data into a list of item values
+  const QList<ModelItemValues> valueList = JsonParser::toItemValuesList(jsonData, ITEM_KEY_STRING);
+  /// for each item values:
+  // NEXT iterate over all value items in the list (or disable updating multiple items for now)
+  // for (ModelItemValues itemValues : valueList) {
+  // }
+  // NEXT encapsulate into updateItem(const ModelItemValues& itemValues)
+  QModelIndex foundIndex = searchItemIndex(valueList.first());
+
+  qDebug() << "Search done!";
+  if (foundIndex == QModelIndex()) {
+    const QString errorMessage = "No matching item found!";
+    qWarning() << errorMessage;
+    return errorMessage;
+  } else {
+    qInfo() << "Item found!";
+    /// update existing item
+    QMap<int, QVariant> roles = valueList.first();
+    setItemData(foundIndex, roles);
+    /// return status what happened in this function (i. e. "Created x items, updated y items.")
+    // return data(foundIndex, ToStringRole).toString();
+    return QString("Item found at row %1.").arg(foundIndex.row());
+  }
+}
+
 bool TableModel::removeRows(int firstRow, int nRows, const QModelIndex& parentIndex) {
   if (parentIndex != QModelIndex()) {
     qWarning() << "Removing of child rows is not supported yet!";
@@ -203,7 +230,7 @@ void TableModel::appendItems(const QByteArray& jsonDoc) { insertItems(-1, jsonDo
 void TableModel::insertItems(int startPosition,
                              const QByteArray& jsonDoc,
                              const QModelIndex& parentIndex) {
-  const QList<ModelItemValues> valueList = JsonParser::toItemValuesList(jsonDoc, ITEM_KEY_STRING);
+  const QList<ModelItemValues> valueList = JsonParser::toItemValuesList(jsonDoc, ITEMS_KEY_STRING);
 
   if (valueList.empty()) {
     /// don't try inserting if no values to insert
@@ -302,3 +329,60 @@ bool TableModel::isEmptyValueEqualToZero(const int role) const {
     return false;
   }
 }
+
+QModelIndex TableModel::searchItemIndex(const ModelItemValues givenItemValues) const {
+  // iterate over indexes to search item : see searchItem(...);
+  // for (const shared_ptr<ModelItem>& item : m_items) {
+  for (int row = 0; row < rowCount(); ++row) {
+    qDebug() << "Processing item at row" << row << "...";
+    QModelIndex itemIndex = index(row, 0);
+    if (isItemEqualToItemValues(itemIndex, givenItemValues)) {
+      qInfo() << "Found item at row" << row << "! Returning its index...";
+      return itemIndex;
+    }
+  }
+  qDebug() << "No matching item found. Returning empty pointer...";
+  return {};
+}
+
+bool TableModel::isItemEqualToItemValues(const QModelIndex& itemIndex,
+                                         const ModelItemValues givenItemValues) const {
+  /// do both have a UUID?
+  QVariant idOfItem = data(itemIndex, IdRole);
+  QVariant given    = givenItemValues.value(IdRole);
+  if (idOfItem.isValid() && given.isValid()) {
+    /// are the UUIDs the same?
+    if (idOfItem.toString() == given.toString()) {
+      qInfo() << "UUIDs are the same.";
+      return true;
+    } else {
+      qDebug() << "UUIDs are NOT the same.";
+      return false;
+    }
+  } else {
+    /// are all other values the same? (for now only USER_FACING_ROLES are checked)
+    QListIterator<UserRoles> i(USER_FACING_ROLES);
+    while (i.hasNext()) {
+      const UserRoles role       = i.next();
+      const QString roleName     = ROLE_NAMES.value(role);
+      const QVariant valueOfItem = data(itemIndex, role);
+      const QVariant givenValue  = givenItemValues.value(role);
+      if (STRING_ROLES.contains(role)) {
+        if (valueOfItem.toString() != givenValue.toString()) {
+          return false;
+        }
+      } else if (INT_ROLES.contains(role)) {
+        if (valueOfItem.toInt() != givenValue.toInt()) {
+          return false;
+        }
+      } else if (DOUBLE_ROLES.contains(role)) {
+        if (valueOfItem.toDouble() != givenValue.toDouble()) {
+          return false;
+        }
+      } else {
+        qCritical() << QString("Can't find data type for role %1!!!").arg(role);
+      }
+    }
+    return true;
+  }
+}

model/tablemodel.h

@@ -8,7 +8,7 @@ class ModelItem;
 
 using namespace std;
 
-typedef QHash<int, QVariant> ModelItemValues;
+typedef QMap<int, QVariant> ModelItemValues;
 
 class TableModel : public QAbstractTableModel {
   Q_OBJECT
@@ -40,6 +40,8 @@ class TableModel : public QAbstractTableModel {
 
   QByteArray jsonDataForServer(const QModelIndex& currentIndex) const;
 
+  QString updateItemsFromJson(const QByteArray& jsonData);
+
  public slots:
   // bool insertRows(int position, int rows, const QModelIndex& parentIndex = QModelIndex())
   // override;
@@ -68,6 +70,9 @@ class TableModel : public QAbstractTableModel {
   QMap<int, QVariant> onlyChangedValues(const QModelIndex& index,
                                         const QMap<int, QVariant>& roleValueMap) const;
   bool isEmptyValueEqualToZero(const int role) const;
+  QModelIndex searchItemIndex(const ModelItemValues givenItemValues) const;
+  bool isItemEqualToItemValues(const QModelIndex& itemIndex,
+                               const ModelItemValues givenItemValues) const;
 };
 
 #endif  // TABLEMODEL_H