Show a progress dialog during Apply

The most time spent during apply is during packet rebuilding.
Unfortunately, there is no feedback from the drone to know the actual
progress, so this is just a busy indicator for now.

I tried to put a jump url to the FAQ on why it takes time, but 'coz the
app cursor is a "wait cursor", user cannot click on any widgets/elements
inside the dialog box - so this won't work.

Iterate on this dialog and what it displays based on user feedback.

client/applymsg.h

@@ -0,0 +1,86 @@
+/*
+Copyright (C) 2019 Srivats P.
+
+This file is part of "Ostinato"
+
+This is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program 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 General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>
+*/
+
+#ifndef _APPLY_MESSAGE_H
+#define _APPLY_MESSAGE_H
+
+#include <QDialog>
+#include <QMainWindow>
+#include <QProgressBar>
+#include <QTimer>
+
+extern QMainWindow *mainWindow;
+
+class ApplyMessage: public QDialog
+{
+public:
+    ApplyMessage(QWidget *parent = Q_NULLPTR);
+
+public slots:
+    void show();
+    virtual void done(int r);
+
+private:
+    QLabel *help_;
+    QTimer *helpTimer_;
+};
+
+ApplyMessage::ApplyMessage(QWidget *parent)
+    : QDialog(parent)
+{
+    auto layout = new QVBoxLayout(this);
+    auto message = new QLabel(tr("Pushing configuration changes to agent "
+                              "and re-building packets ..."), this);
+    auto progress = new QProgressBar(this);
+    progress->setRange(0, 0);
+    progress->setTextVisible(false);
+    help_ = new QLabel(tr("<b>This may take some time</b>"), this);
+    help_->setAlignment(Qt::AlignCenter);
+    layout->addWidget(message);
+    layout->addWidget(progress);
+    layout->addWidget(help_);
+
+    helpTimer_ = new QTimer(this);
+    helpTimer_->setSingleShot(true);
+    helpTimer_->setInterval(4000);
+    connect(helpTimer_, SIGNAL(timeout()), help_, SLOT(show()));
+}
+
+void ApplyMessage::show()
+{
+    help_->hide(); // shown when helpTimer_ expires
+
+    QWidget *parent = parentWidget();
+    if (!parent)
+        parent = mainWindow;
+    move(parent->frameGeometry().center() - rect().center());
+    setModal(true);
+    QDialog::show();
+
+    helpTimer_->start();
+}
+
+void ApplyMessage::done(int r)
+{
+    helpTimer_->stop();
+    QDialog::done(r);
+}
+
+#endif
+

client/portgroup.cpp

@@ -669,6 +669,8 @@ void PortGroup::processModifyStreamAck(int portIndex,
     logInfo(id(), mPorts[portIndex]->id(), QString("All port changes applied"));
     mPorts[portIndex]->when_syncComplete();
 
+    emit applyFinished();
+
     mainWindow->setEnabled(true);
     QApplication::restoreOverrideCursor();
     delete controller;

client/portgroup.h

@@ -171,6 +171,7 @@ public:
     void processStreamStatsList(PbRpcController *controller);
 
 signals:
+    void applyFinished();
     void portGroupDataChanged(int portGroupId, int portId = 0xFFFF);
     void portListAboutToBeChanged(quint32 portGroupId);
     void portListChanged(quint32 portGroupId);

client/portswindow.cpp

@@ -19,6 +19,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>
 
 #include "portswindow.h"
 
+#include "applymsg.h"
 #include "deviceswidget.h"
 #include "portconfigdialog.h"
 #include "settings.h"
@@ -52,6 +53,7 @@ PortsWindow::PortsWindow(PortGroupList *pgl, QWidget *parent)
     plm = pgl;
 
     setupUi(this);
+    applyMsg_ = new ApplyMessage();
     devicesWidget->setPortGroupList(plm);
 
     tvPortList->header()->hide();
@@ -173,6 +175,7 @@ PortsWindow::~PortsWindow()
 {
     delete delegate;
     delete proxyPortModel;
+    delete applyMsg_;
 }
 
 int PortsWindow::portGroupCount()
@@ -647,6 +650,11 @@ void PortsWindow::on_pbApply_clicked()
         goto _exit;
     }
 
+    disconnect(applyMsg_);
+    connect(&(plm->portGroup(curPortGroup)), SIGNAL(applyFinished()),
+            applyMsg_, SLOT(hide()));
+    applyMsg_->show();
+
     // FIXME(HI): shd this be a signal?
     //portGroup.when_configApply(port);
     // FIXME(MED): mixing port id and index!!!

client/portswindow.h

@@ -25,6 +25,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>
 #include "ui_portswindow.h"
 #include "portgrouplist.h"
 
+class ApplyMessage;
 class QAbstractItemDelegate;
 class QProgressDialog;
 class QSortFilterProxyModel;
@@ -61,6 +62,7 @@ private:
     QString        lastNewPortGroup;
     QAbstractItemDelegate *delegate;
     QSortFilterProxyModel *proxyPortModel;
+    ApplyMessage *applyMsg_;
 
 public slots:
     void showMyReservedPortsOnly(bool enabled);