From c081b3a66526eafafa0ed62e0e8c60b604d2b984 Mon Sep 17 00:00:00 2001
From: Matthieu Gautier <mgautier@kymeria.fr>
Date: Thu, 13 Dec 2018 18:06:11 +0100
Subject: [PATCH] Disable back/forward buttons when there is no history

Fix #82
---
 src/kiwixapp.cpp   |  2 ++
 src/mainwindow.cpp |  5 +++++
 src/mainwindow.h   |  2 ++
 src/tabbar.cpp     | 14 ++++++++++++--
 src/topwidget.cpp  |  2 ++
 src/topwidget.h    |  2 +-
 6 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/src/kiwixapp.cpp b/src/kiwixapp.cpp
index 49e5a49..30af0b2 100644
--- a/src/kiwixapp.cpp
+++ b/src/kiwixapp.cpp
@@ -364,6 +364,8 @@ void KiwixApp::createAction()
 }
 
 void KiwixApp::postInit() {
+    connect(mp_tabWidget, &TabBar::webActionEnabledChanged,
+            mp_mainWindow->getTopWidget(), &TopWidget::handleWebActionEnabledChanged);
     connect(mp_tabWidget, &TabBar::currentTitleChanged, this,
             [=](const QString& title) { emit currentTitleChanged(title); });
     emit(m_library.booksChanged());
diff --git a/src/mainwindow.cpp b/src/mainwindow.cpp
index 93639a3..e26a622 100644
--- a/src/mainwindow.cpp
+++ b/src/mainwindow.cpp
@@ -45,6 +45,11 @@ TabBar* MainWindow::getTabBar()
     return mp_ui->tabBar;
 }
 
+TopWidget *MainWindow::getTopWidget()
+{
+    return mp_ui->mainToolBar;
+}
+
 QStackedWidget *MainWindow::getSideDockWidget()
 {
     return mp_ui->sideBar;
diff --git a/src/mainwindow.h b/src/mainwindow.h
index 391861d..87b7c04 100644
--- a/src/mainwindow.h
+++ b/src/mainwindow.h
@@ -5,6 +5,7 @@
 #include <QDockWidget>
 #include "webview.h"
 #include "tabbar.h"
+#include "topwidget.h"
 #include "tocsidebar.h"
 #include "about.h"
 #include "contentmanagerside.h"
@@ -22,6 +23,7 @@ public:
     ~MainWindow();
 
     TabBar*   getTabBar();
+    TopWidget* getTopWidget();
     QStackedWidget* getSideDockWidget();
     ContentManagerSide* getSideContentManager();
 
diff --git a/src/tabbar.cpp b/src/tabbar.cpp
index 0ba18ad..788cc7c 100644
--- a/src/tabbar.cpp
+++ b/src/tabbar.cpp
@@ -3,6 +3,7 @@
 #include "kiwixapp.h"
 #include <QAction>
 #include <QTimer>
+#include <QWebEnginePage>
 
 #define QUITIFNULL(VIEW) if (nullptr==(VIEW)) { return; }
 #define QUITIFNOTCURRENT(VIEW) if((VIEW)!=currentWidget()) {return;}
@@ -95,8 +96,17 @@ WebView* TabBar::createNewTab(bool setCurrent)
             [=](const QString& zimId) {
                 QUITIFNOTCURRENT(webView);
                 emit currentZimIdChanged(zimId);
-            }
-    );
+            });
+    connect(webView->page()->action(QWebEnginePage::Back), &QAction::changed,
+            [=]() {
+                QUITIFNOTCURRENT(webView);
+                emit webActionEnabledChanged(QWebEnginePage::Back, webView->isWebActionEnabled(QWebEnginePage::Back));
+            });
+    connect(webView->page()->action(QWebEnginePage::Forward), &QAction::changed,
+            [=]() {
+                QUITIFNOTCURRENT(webView);
+                emit webActionEnabledChanged(QWebEnginePage::Forward, webView->isWebActionEnabled(QWebEnginePage::Forward));
+            });
     // Ownership of webview is passed to the tabWidget
     mp_stackedWidget->addWidget(webView);
     auto index = addTab("");
diff --git a/src/topwidget.cpp b/src/topwidget.cpp
index 1a44644..c2f264e 100644
--- a/src/topwidget.cpp
+++ b/src/topwidget.cpp
@@ -14,6 +14,7 @@ TopWidget::TopWidget(QWidget *parent) :
     mp_historyBackAction->setIcon(QIcon(":/icons/back.svg"));
     mp_historyBackAction->setText(tr("back"));
     mp_historyBackAction->setToolTip(tr("back"));
+    mp_historyBackAction->setEnabled(false);
     connect(mp_historyBackAction, &QAction::triggered, [](){
         KiwixApp::instance()->getTabWidget()->triggerWebPageAction(QWebEnginePage::Back);
     });
@@ -22,6 +23,7 @@ TopWidget::TopWidget(QWidget *parent) :
     mp_historyForwardAction->setIcon(QIcon(":/icons/forward.svg"));
     mp_historyForwardAction->setText(tr("forward"));
     mp_historyForwardAction->setToolTip(tr("forward"));
+    mp_historyForwardAction->setEnabled(false);
     connect(mp_historyForwardAction, &QAction::triggered, [](){
         KiwixApp::instance()->getTabWidget()->triggerWebPageAction(QWebEnginePage::Forward);
     });
diff --git a/src/topwidget.h b/src/topwidget.h
index e492193..4b95058 100644
--- a/src/topwidget.h
+++ b/src/topwidget.h
@@ -25,7 +25,7 @@ private:
     QPoint m_cursorPos;
     ulong m_timestamp;
 
-private slots:
+public slots:
     void handleWebActionEnabledChanged(QWebEnginePage::WebAction action, bool enabled);
 };