/*=========================================================================

   Program: ParaView
   Module:    pqHelpWindow.cxx

   Copyright (c) 2005,2006 Sandia Corporation, Kitware Inc.
   All rights reserved.

   ParaView is a free software; you can redistribute it and/or modify it
   under the terms of the ParaView license version 1.2.

   See License_v1.2.txt for the full ParaView license.
   A copy of this license can be obtained by contacting
   Kitware Inc.
   28 Corporate Drive
   Clifton Park, NY 12065
   USA

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

========================================================================*/
#include "pqHelpWindow.h"
#include "pqApplicationCore.h"
#include "pqQtWidgetsConfig.h" // for PARAVIEW_USE_QTWEBENGINE
#include "pqSettings.h"
#include "ui_pqHelpWindow.h"

#include <QDebug>
#include <QDesktopServices>
#include <QHelpContentWidget>
#include <QHelpEngine>
#include <QHelpIndexWidget>
#include <QHelpSearchEngine>
#include <QHelpSearchQueryWidget>
#include <QHelpSearchResultWidget>
#include <QPointer>
#include <QUrl>

#include <cassert>

class pqBrowser
{
public:
  pqBrowser() = default;
  virtual ~pqBrowser() = default;
  virtual QWidget* widget() const = 0;
  virtual void setUrl(const QUrl& url) = 0;
  virtual QUrl url() = 0;
  virtual QUrl goBackward() = 0;
  virtual QUrl goForward() = 0;
  virtual bool canGoBackward() = 0;
  virtual bool canGoForward() = 0;

private:
  Q_DISABLE_COPY(pqBrowser)
};

template <class T>
class pqBrowserTemplate : public pqBrowser
{
  QPointer<T> Widget;

public:
  pqBrowserTemplate(QHelpEngine* engine, pqHelpWindow* self)
  {
    this->Widget = T::newInstance(engine, self);
  }
  ~pqBrowserTemplate() override { delete this->Widget; }
  QWidget* widget() const override { return this->Widget; }
  void setUrl(const QUrl& url) override { this->Widget->setUrl(url); }
  QUrl url() override { return this->Widget->url(); }
  QUrl goBackward() override { return this->Widget->goBackward(); }
  QUrl goForward() override { return this->Widget->goForward(); }
  bool canGoBackward() override { return this->Widget->canGoBackward(); }
  bool canGoForward() override { return this->Widget->canGoForward(); }
};

#if PARAVIEW_USE_QTWEBENGINE
#include "pqHelpWindowWebEngine.h"
typedef pqBrowserTemplate<pqWebView> PQBROWSER_TYPE;
#else
#include "pqHelpWindowNoWebEngine.h"
typedef pqBrowserTemplate<pqTextBrowser> PQBROWSER_TYPE;
#endif

// ****************************************************************************
//            CLASS pqHelpWindow
// ****************************************************************************

//-----------------------------------------------------------------------------
class pqHelpWindow::pqInternals : public Ui::pqHelpWindow
{
public:
  QString NameSpaceName;
};

//-----------------------------------------------------------------------------
pqHelpWindow::pqHelpWindow(QHelpEngine* engine, QWidget* parentObject, Qt::WindowFlags parentFlags)
  : Superclass(parentObject, parentFlags)
  , HelpEngine(engine)
  , Browser(new PQBROWSER_TYPE(this->HelpEngine, this))
  , Internals(new pqInternals())
{
  assert(engine != nullptr);

  this->Internals->setupUi(this);

  QObject::connect(this->HelpEngine, &QHelpEngine::warning, this, &pqHelpWindow::helpWarnings);

  this->setTabPosition(Qt::AllDockWidgetAreas, QTabWidget::North);

  this->tabifyDockWidget(this->Internals->contentsDock, this->Internals->searchDock);
  this->Internals->contentsDock->setWidget(this->HelpEngine->contentWidget());
  this->Internals->contentsDock->raise();

  QWidget* searchPane = new QWidget(this);
  QVBoxLayout* vbox = new QVBoxLayout();
  searchPane->setLayout(vbox);
  vbox->addWidget(engine->searchEngine()->queryWidget());
  vbox->addWidget(engine->searchEngine()->resultWidget());
  this->Internals->searchDock->setWidget(searchPane);

  QObject::connect(engine->searchEngine()->queryWidget(), &QHelpSearchQueryWidget::search, this,
    &pqHelpWindow::search);
  QObject::connect(engine->searchEngine()->resultWidget(),
    &QHelpSearchResultWidget::requestShowLink, this,
    QOverload<const QUrl&>::of(&pqHelpWindow::showPage));

  this->setCentralWidget(this->Browser->widget());

  QObject::connect(
    this->Internals->actionHome, &QAction::triggered, this, [=]() { this->showHomePage(); });

  this->Internals->actionBackward->setEnabled(false);
  QObject::connect(
    this->Internals->actionBackward, &QAction::triggered, this, &pqHelpWindow::goBackward);

  this->Internals->actionForward->setEnabled(false);
  QObject::connect(
    this->Internals->actionForward, &QAction::triggered, this, &pqHelpWindow::goForward);

  QObject::connect(this->Internals->actionSaveAsHomepage, &QAction::triggered, this,
    &pqHelpWindow::saveCurrentHomePage);

  QWidget* spacer = new QWidget();
  spacer->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
  // toolBar is a pointer to an existing toolbar
  this->Internals->toolBar->insertWidget(this->Internals->actionSaveAsHomepage, spacer);

  QObject::connect(this->HelpEngine->contentWidget(), SIGNAL(linkActivated(const QUrl&)), this,
    SLOT(showPage(const QUrl&)));
}

//-----------------------------------------------------------------------------
pqHelpWindow::~pqHelpWindow() = default;

//-----------------------------------------------------------------------------
void pqHelpWindow::showPage(const QString& url)
{
  this->showPage(QUrl(url));
}

//-----------------------------------------------------------------------------
void pqHelpWindow::showPage(const QUrl& url)
{
  if (url.scheme() == "http")
  {
    QDesktopServices::openUrl(url);
  }
  else
  {
    this->Browser->setUrl(url);
  }
}

//-----------------------------------------------------------------------------
void pqHelpWindow::search()
{
  QString query = this->HelpEngine->searchEngine()->queryWidget()->searchInput();
  this->HelpEngine->searchEngine()->search(query);
}

//-----------------------------------------------------------------------------
void pqHelpWindow::setNameSpace(const QString& namespace_name)
{
  this->Internals->NameSpaceName = namespace_name;
}

//-----------------------------------------------------------------------------
// PARAVIEW_DEPRECATED_IN_5_12_0
void pqHelpWindow::showHomePage(const QString& namespace_name)
{
  this->setNameSpace(namespace_name);
  this->showHomePage();
}

//-----------------------------------------------------------------------------
void pqHelpWindow::showHomePage()
{
  QUrl homePage;

  // First, search for valid saved homepage
  pqSettings* settings = pqApplicationCore::instance()->settings();
  QString settingKey = QString("HelpWindow.%1.HomePage").arg(this->Internals->NameSpaceName);
  QUrl savedHomePage =
    settings->contains(settingKey) ? settings->value(settingKey).toUrl() : QUrl();

  if (!savedHomePage.isEmpty())
  {
    if (!this->HelpEngine->fileData(savedHomePage).isEmpty())
    {
      homePage = savedHomePage;
    }
    else
    {
      qWarning() << "Saved custom home page not found : " << savedHomePage
                 << ".\nDisplaying default home page instead.";
    }
  }

  // If no valid homepage is found, search for the default one
  if (homePage.isEmpty())
  {
    // Locate a file named index.html in the help engine registered files to use as homepage.
    QList<QUrl> html_pages =
      this->HelpEngine->files(this->Internals->NameSpaceName, QStringList(), "html");
    Q_FOREACH (QUrl url, html_pages)
    {
      if (url.path().endsWith("index.html"))
      {
        homePage = url;
      }
    }
  }

  if (homePage.isEmpty())
  {
    qWarning() << "Could not locate index.html";
    return;
  }

  this->showPage(homePage);
  QHelpContentWidget* widget = this->HelpEngine->contentWidget();
  widget->setCurrentIndex(widget->indexOf(homePage));
}

//-----------------------------------------------------------------------------
void pqHelpWindow::saveCurrentHomePage()
{
  pqSettings* settings = pqApplicationCore::instance()->settings();
  settings->setValue(
    QString("HelpWindow.%1.HomePage").arg(this->Internals->NameSpaceName), this->Browser->url());
}

//-----------------------------------------------------------------------------
void pqHelpWindow::goBackward()
{
  QUrl newUrl = this->Browser->goBackward();
  QHelpContentWidget* widget = this->HelpEngine->contentWidget();
  widget->setCurrentIndex(widget->indexOf(newUrl));
}

//-----------------------------------------------------------------------------
void pqHelpWindow::goForward()
{
  QUrl newUrl = this->Browser->goForward();
  QHelpContentWidget* widget = this->HelpEngine->contentWidget();
  widget->setCurrentIndex(widget->indexOf(newUrl));
}

//-----------------------------------------------------------------------------
void pqHelpWindow::updateHistoryButtons()
{
  this->Internals->actionBackward->setEnabled(this->Browser->canGoBackward());
  this->Internals->actionForward->setEnabled(this->Browser->canGoForward());
}
