1 files changed, 89 insertions, 0 deletions
diff --git a/api/logic/resources/ResourceProxyModel.cpp b/api/logic/resources/ResourceProxyModel.cpp
new file mode 100644
index 00000000..f026d9a9
--- /dev/null
+++ b/api/logic/resources/ResourceProxyModel.cpp
@@ -0,0 +1,89 @@
+#include "ResourceProxyModel.h"
+
+#include <QItemSelectionRange>
+
+#include "Resource.h"
+#include "ResourceObserver.h"
+
+class ModelResourceObserver : public ResourceObserver
+{
+public:
+	explicit ModelResourceObserver(const QModelIndex &index, const int role)
+		: m_index(index), m_role(role)
+	{
+		qRegisterMetaType<QVector<int>>("QVector<int>");
+	}
+
+	void resourceUpdated() override
+	{
+		if (m_index.isValid())
+		{
+			// the resource changed, pretend to be the model and notify the views of the update. they will re-poll the model which will return the new resource value
+			QMetaObject::invokeMethod(const_cast<QAbstractItemModel *>(m_index.model()),
+									  "dataChanged", Qt::QueuedConnection,
+									  Q_ARG(QModelIndex, m_index), Q_ARG(QModelIndex, m_index), Q_ARG(QVector<int>, QVector<int>() << m_role));
+		}
+	}
+
+private:
+	QPersistentModelIndex m_index;
+	int m_role;
+};
+
+ResourceProxyModel::ResourceProxyModel(const int resultTypeId, QObject *parent)
+	: QIdentityProxyModel(parent), m_resultTypeId(resultTypeId)
+{
+}
+
+QVariant ResourceProxyModel::data(const QModelIndex &proxyIndex, int role) const
+{
+	const QModelIndex mapped = mapToSource(proxyIndex);
+	// valid cell that's a Qt::DecorationRole and that contains a non-empty string
+	if (mapped.isValid() && role == Qt::DecorationRole && !mapToSource(proxyIndex).data(role).toString().isEmpty())
+	{
+		// do we already have a resource for this index?
+		if (!m_resources.contains(mapped))
+		{
+			Resource::Ptr placeholder;
+			const QVariant placeholderIdentifier = mapped.data(PlaceholderRole);
+			if (!placeholderIdentifier.isNull() && placeholderIdentifier.type() == QVariant::String)
+			{
+				placeholder = Resource::create(placeholderIdentifier.toString());
+			}
+
+			// create the Resource and apply the observer for models
+			Resource::Ptr res = Resource::create(mapToSource(proxyIndex).data(role).toString(), placeholder)
+					->applyTo(new ModelResourceObserver(proxyIndex, role));
+
+			m_resources.insert(mapped, res);
+		}
+
+		return m_resources.value(mapped)->getResourceInternal(m_resultTypeId);
+	}
+	// otherwise fall back to the source model
+	return mapped.data(role);
+}
+
+void ResourceProxyModel::setSourceModel(QAbstractItemModel *model)
+{
+	if (sourceModel())
+	{
+		disconnect(sourceModel(), 0, this, 0);
+	}
+	if (model)
+	{
+		connect(model, &QAbstractItemModel::dataChanged, this, [this](const QModelIndex &tl, const QModelIndex &br, const QVector<int> &roles)
+		{
+			// invalidate resources so that they will be re-created
+			if (roles.contains(Qt::DecorationRole) || roles.contains(PlaceholderRole) || roles.isEmpty())
+			{
+				const QItemSelectionRange range(tl, br);
+				for (const QModelIndex &index : range.indexes())
+				{
+					m_resources.remove(index);
+				}
+			}
+		});
+	}
+	QIdentityProxyModel::setSourceModel(model);
+}