/** 
 * @file llviewerhelp.cpp
 * @brief Utility functions for the Help system
 * @author Tofu Linden
 *
 * $LicenseInfo:firstyear=2009&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2010, Linden Research, Inc.
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License only.
 * 
 * This library 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
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 * 
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 */

#include "llviewerprecompiledheaders.h"

#include "llcommandhandler.h"
#include "llfloaterhelpbrowser.h"
#include "llfloaterreg.h"
#include "llfocusmgr.h"
#include "llviewercontrol.h"
#include "llappviewer.h"
#include "lllogininstance.h"

#include "llviewerhelputil.h"
#include "llviewerhelp.h"

// support for secondlife:///app/help/{TOPIC} SLapps
class LLHelpHandler : public LLCommandHandler
{
public:
	// requests will be throttled from a non-trusted browser
	LLHelpHandler() : LLCommandHandler("help", UNTRUSTED_THROTTLE) {}

	bool handle(const LLSD& params, const LLSD& query_map, LLMediaCtrl* web)
	{
		LLViewerHelp* vhelp = LLViewerHelp::getInstance();
		if (! vhelp)
		{
			return false;
		}

		// get the requested help topic name, or use the fallback if none
		std::string help_topic = vhelp->defaultTopic();
		if (params.size() >= 1)
		{
			help_topic = params[0].asString();
		}

		vhelp->showTopic(help_topic);
		return true;
	}
};
LLHelpHandler gHelpHandler;

//////////////////////////////
// implement LLHelp interface

void LLViewerHelp::showTopic(const std::string &topic)
{
	// allow overriding the help server with a local help file
	if( gSavedSettings.getBOOL("HelpUseLocal") )
	{
		showHelp();
		LLFloaterHelpBrowser* helpbrowser = dynamic_cast<LLFloaterHelpBrowser*>(LLFloaterReg::getInstance("help_browser"));
		helpbrowser->navigateToLocalPage( "help-offline" , "index.html" );
		return;
	}

	// if the help topic is empty, use the default topic
	std::string help_topic = topic;
	if (help_topic.empty())
	{
		help_topic = defaultTopic();
	}

	// f1 help topic means: if the user is not logged in yet, show
	// the pre-login topic instead of the default fallback topic,
	// otherwise show help for the focused item
	if (help_topic == f1HelpTopic())
	{
		help_topic = getTopicFromFocus();
		if (help_topic == defaultTopic() && ! LLLoginInstance::getInstance()->authSuccess())
		{
			help_topic = preLoginTopic();
		}
	}

	// work out the URL for this topic and display it 
	showHelp();
	
	std::string helpURL = LLViewerHelpUtil::buildHelpURL( help_topic );
	setRawURL(helpURL);
}

std::string LLViewerHelp::defaultTopic()
{
	// *hack: to be done properly
	return "this_is_fallbacktopic";
}

std::string LLViewerHelp::preLoginTopic()
{
	// *hack: to be done properly
	return "pre_login_help";
}

std::string LLViewerHelp::f1HelpTopic()
{
	// *hack: to be done properly
	return "f1_help";
}

//////////////////////////////
// our own interfaces

std::string LLViewerHelp::getTopicFromFocus()
{
	// use UI element with viewer's keyboard focus as basis for searching
	LLUICtrl* focused = dynamic_cast<LLUICtrl*>(gFocusMgr.getKeyboardFocus());

	if (focused)
	{
		std::string topic;
		if (focused->findHelpTopic(topic))
		{
			return topic;
		}
	}

	// didn't find a help topic in the UI hierarchy for focused
	// element, return the fallback topic name instead.
	return defaultTopic();
}

// static 
void LLViewerHelp::showHelp()
{
	LLFloaterHelpBrowser* helpbrowser = dynamic_cast<LLFloaterHelpBrowser*>(LLFloaterReg::getInstance("help_browser"));
	if (helpbrowser)
	{
		BOOL visible = TRUE;
		BOOL take_focus = TRUE;
		helpbrowser->setVisible(visible);
		helpbrowser->setFrontmost(take_focus);
	}
	else
	{
		llwarns << "Eep, help_browser floater not found" << llendl;
	}
}

// static
void LLViewerHelp::setRawURL(std::string url)
{
	LLFloaterHelpBrowser* helpbrowser = dynamic_cast<LLFloaterHelpBrowser*>(LLFloaterReg::getInstance("help_browser"));
	if (helpbrowser)
	{
		helpbrowser->openMedia(url);	
	}
	else
	{
		llwarns << "Eep, help_browser floater not found" << llendl;
	}
}