# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.

# Set the default content pack to the Mozilla content pack. Use the
# setHelpFileURI function to set this value.
var helpFileURI;

# openHelp - Opens up the Mozilla Help Viewer with the specified
#    topic and content pack.
# see http://www.mozilla.org/projects/help-viewer/content_packs.html
function openHelp(topic, contentPack)
{
# helpFileURI is the content pack to use in this function. If contentPack is defined,
# use that and set the helpFileURI to that value so that it will be the default.
  helpFileURI = contentPack || helpFileURI;

# Try to find previously opened help.
  var topWindow = locateHelpWindow(helpFileURI);

  if ( topWindow ) {
# Open topic in existing window.
    topWindow.focus();
    topWindow.displayTopic(topic);
  } else {
# Open topic in new window.
    const params = Components.classes["@mozilla.org/embedcomp/dialogparam;1"]
                             .createInstance(Components.interfaces.nsIDialogParamBlock);
    params.SetNumberStrings(2);
    params.SetString(0, helpFileURI);
    params.SetString(1, topic);
    const ww = Components.classes["@mozilla.org/embedcomp/window-watcher;1"]
                         .getService(Components.interfaces.nsIWindowWatcher);
#ifdef XP_WIN
#define HELP_ALWAYS_RAISED_TOGGLE
#endif
#ifdef HELP_ALWAYS_RAISED_TOGGLE
    ww.openWindow(null, "chrome://help/content/help.xul", "_blank", "chrome,all,alwaysRaised,dialog=no", params);
#else
    ww.openWindow(null, "chrome://help/content/help.xul", "_blank", "chrome,all,dialog=no", params);
#endif
  }
}

# setHelpFileURI - Sets the default content pack to use in the Help Viewer
function setHelpFileURI(rdfURI)
{
  helpFileURI = rdfURI;
}

# Locate existing help window for this content pack.
function locateHelpWindow(contentPack) {
    const windowManagerInterface = Components
        .classes['@mozilla.org/appshell/window-mediator;1'].getService()
        .QueryInterface(Components.interfaces.nsIWindowMediator);
    const iterator = windowManagerInterface.getEnumerator("mozilla:help");
    var topWindow = null;
    var aWindow;

# Loop through help windows looking for one with selected content
# pack.
    while (iterator.hasMoreElements()) {
        aWindow = iterator.getNext();
        if (!aWindow.closed && aWindow.getHelpFileURI() == contentPack) {
            topWindow = aWindow;
        }
    }
    return topWindow;
}
