From a84add82f1a13bf549ab50e34ec6fe2f07901043 Mon Sep 17 00:00:00 2001
From: itsmattkc <itsmattkc@gmail.com>
Date: Tue, 2 Jul 2019 19:29:04 -0700
Subject: [PATCH] began drag n drop support in projectexplorer

---
 app/project/project.cpp                       |  6 ++
 app/project/projectviewmodel.cpp              | 69 +++++++++++++++++++
 app/project/projectviewmodel.h                |  5 ++
 .../projectexplorertreeview.cpp               | 12 ++++
 4 files changed, 92 insertions(+)

diff --git a/app/project/project.cpp b/app/project/project.cpp
index d5e518026..8cbfb0036 100644
--- a/app/project/project.cpp
+++ b/app/project/project.cpp
@@ -28,6 +28,12 @@ Project::Project()
   Folder* f = new Folder();
   f->set_name("Foldery Boy");
   root()->add_child(f);
+  Folder* f2 = new Folder();
+  f2->set_name("DarnMan");
+  root()->add_child(f2);
+  Folder* f3 = new Folder();
+  f3->set_name("DamnDude");
+  f2->add_child(f3);
   // END Test code
 }
 
diff --git a/app/project/projectviewmodel.cpp b/app/project/projectviewmodel.cpp
index 79c517e10..a526fd89c 100644
--- a/app/project/projectviewmodel.cpp
+++ b/app/project/projectviewmodel.cpp
@@ -20,6 +20,9 @@
 
 #include "projectviewmodel.h"
 
+#include <QDebug>
+#include <QMimeData>
+
 ProjectViewModel::ProjectViewModel(QObject *parent) :
   QAbstractItemModel(parent),
   project_(nullptr)
@@ -193,3 +196,69 @@ bool ProjectViewModel::hasChildren(const QModelIndex &parent) const
   // Otherwise, return default behavior
   return QAbstractItemModel::hasChildren(parent);
 }
+
+Qt::ItemFlags ProjectViewModel::flags(const QModelIndex &index) const
+{
+  return Qt::ItemIsDragEnabled | Qt::ItemIsDropEnabled | QAbstractItemModel::flags(index);
+}
+
+QStringList ProjectViewModel::mimeTypes() const
+{
+  return {"application/x-oliveprojectitemdata"};
+}
+
+QMimeData *ProjectViewModel::mimeData(const QModelIndexList &indexes) const
+{
+  QMimeData* data = new QMimeData();
+
+  QByteArray encoded_data;
+  QDataStream stream(&encoded_data, QIODevice::WriteOnly);
+
+  foreach (QModelIndex index, indexes) {
+    if (index.isValid()) {
+      stream << reinterpret_cast<quintptr>(index.internalPointer());
+    }
+  }
+
+  data->setData("application/x-oliveprojectitemdata", encoded_data);
+
+  return data;
+}
+
+bool ProjectViewModel::dropMimeData(const QMimeData *data, Qt::DropAction action, int row, int column, const QModelIndex &parent)
+{
+  // Default recommended checks from https://doc.qt.io/qt-5/model-view-programming.html#using-drag-and-drop-with-item-views
+  if (!canDropMimeData(data, action, row, column, parent)) {
+    return false;
+  }
+
+  if (action == Qt::IgnoreAction) {
+    return true;
+  }
+
+  // Probe mime data for its format
+  QStringList mime_formats = data->formats();
+
+  if (mime_formats.contains("application/x-oliveprojectitemdata")) {
+    // Data is drag/drop data from this model
+    QByteArray model_data = data->data("application/x-oliveprojectitemdata");
+
+    // Use stream to deserialize the data
+    QDataStream stream(&model_data, QIODevice::ReadOnly);
+
+    // Variables to deserialize into
+    quintptr item_ptr;
+
+    // Loop through all data
+    while (!stream.atEnd()) {
+      stream >> item_ptr;
+
+      Item* item = reinterpret_cast<Item*>(item_ptr);
+      qDebug() << "Dragged" << item->name();
+    }
+
+    return true;
+  }
+
+  return false;
+}
diff --git a/app/project/projectviewmodel.h b/app/project/projectviewmodel.h
index d2c437201..29fb66b7d 100644
--- a/app/project/projectviewmodel.h
+++ b/app/project/projectviewmodel.h
@@ -83,6 +83,11 @@ public:
   virtual QVariant headerData(int section, Qt::Orientation orientation, int role = Qt::DisplayRole) const override;
   virtual bool hasChildren(const QModelIndex &parent = QModelIndex()) const override;
 
+  /** Drag and drop support */
+  virtual Qt::ItemFlags flags(const QModelIndex &index) const override;
+  virtual QStringList mimeTypes() const override;
+  virtual QMimeData * mimeData(const QModelIndexList &indexes) const override;
+  virtual bool dropMimeData(const QMimeData *data, Qt::DropAction action, int row, int column, const QModelIndex &parent) override;
 private:
   Project* project_;
 
diff --git a/app/widget/projectexplorer/projectexplorertreeview.cpp b/app/widget/projectexplorer/projectexplorertreeview.cpp
index 9063fb7f8..5cc3c6e80 100644
--- a/app/widget/projectexplorer/projectexplorertreeview.cpp
+++ b/app/widget/projectexplorer/projectexplorertreeview.cpp
@@ -27,6 +27,18 @@ ProjectExplorerTreeView::ProjectExplorerTreeView(QWidget *parent) :
 {
   // Set selection mode (allows multiple item selection)
   setSelectionMode(QAbstractItemView::ExtendedSelection);
+
+  // Allow dragging and dropping
+  setDragDropMode(QAbstractItemView::DragDrop);
+
+  // Enable dragging
+  setDragEnabled(true);
+
+  // Allow dropping from external sources
+  setAcceptDrops(true);
+
+  // Set context menu to emit a signal
+  setContextMenuPolicy(Qt::CustomContextMenu);
 }
 
 void ProjectExplorerTreeView::mouseDoubleClickEvent(QMouseEvent *event)