/** 
 * @file lllandmarklist.cpp
 * @brief Landmark asset list class
 *
 * $LicenseInfo:firstyear=2002&license=viewerlgpl$
 * 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 "lllandmarklist.h"

#include "message.h"
#include "llassetstorage.h"

#include "llappviewer.h"
#include "llagent.h"
#include "llvfile.h"
#include "llviewerstats.h"

// Globals
LLLandmarkList gLandmarkList;

// number is mostly arbitrary, but it should be below DEFAULT_QUEUE_SIZE pool size,
// which is 4096, to not overfill the pool if user has more than 4K of landmarks
// and it should leave some space for other potential simultaneous asset request
const S32 MAX_SIMULTANEOUS_REQUESTS = 512;


////////////////////////////////////////////////////////////////////////////
// LLLandmarkList

LLLandmarkList::~LLLandmarkList()
{
	std::for_each(mList.begin(), mList.end(), DeletePairedPointer());
	mList.clear();
}

LLLandmark* LLLandmarkList::getAsset(const LLUUID& asset_uuid, loaded_callback_t cb)
{
	LLLandmark* landmark = get_ptr_in_map(mList, asset_uuid);
	if(landmark)
	{
		LLVector3d dummy;
		if(cb && !landmark->getGlobalPos(dummy))
		{
			// landmark is not completely loaded yet
			loaded_callback_map_t::value_type vt(asset_uuid, cb);
			mLoadedCallbackMap.insert(vt);
		}
		return landmark;
	}
	else
	{
	    if ( mBadList.find(asset_uuid) != mBadList.end() )
		{
			return NULL;
		}
	    if ( mWaitList.find(asset_uuid) != mWaitList.end() )
		{
            // Landmark is sheduled for download, but not requested yet
			return NULL;
		}
		
		landmark_requested_list_t::iterator iter = mRequestedList.find(asset_uuid);
		if (iter != mRequestedList.end())
		{
			const F32 rerequest_time = 30.f; // 30 seconds between requests
			if (gFrameTimeSeconds - iter->second < rerequest_time)
			{
				return NULL;
			}
		}
		
		if (cb)
		{
			loaded_callback_map_t::value_type vt(asset_uuid, cb);
			mLoadedCallbackMap.insert(vt);
		}

        if (mRequestedList.size() > MAX_SIMULTANEOUS_REQUESTS)
        {
            // Workarounds for corutines pending list size limit:
            // Postpone download till queue is emptier.
            // Coroutines have own built in 'pending' list, but unfortunately
            // it is too small compared to potential amount of landmarks
            // or assets.
            mWaitList.insert(asset_uuid);
            return NULL;
        }

        mRequestedList[asset_uuid] = gFrameTimeSeconds;

        // Note that getAssetData can callback immediately and cleans mRequestedList
		gAssetStorage->getAssetData(asset_uuid,
									LLAssetType::AT_LANDMARK,
									LLLandmarkList::processGetAssetReply,
									NULL);
	}
	return NULL;
}

// static
void LLLandmarkList::processGetAssetReply(
	LLVFS *vfs,
	const LLUUID& uuid,
	LLAssetType::EType type,
	void* user_data,
	S32 status, 
	LLExtStat ext_status )
{
	if( status == 0 )
	{
		LLVFile file(vfs, uuid, type);
		S32 file_length = file.getSize();

		std::vector<char> buffer(file_length + 1);
		file.read( (U8*)&buffer[0], file_length);
		buffer[ file_length ] = 0;

		LLLandmark* landmark = LLLandmark::constructFromString(&buffer[0]);
		if (landmark)
		{
			gLandmarkList.mList[ uuid ] = landmark;
			gLandmarkList.mRequestedList.erase(uuid);
			
			LLVector3d pos;
			if(!landmark->getGlobalPos(pos))
			{
				LLUUID region_id;
				if(landmark->getRegionID(region_id))
				{
					LLLandmark::requestRegionHandle(
						gMessageSystem,
						gAgent.getRegionHost(),
						region_id,
						boost::bind(&LLLandmarkList::onRegionHandle, &gLandmarkList, uuid));
				}

				// the callback will be called when we get the region handle.
			}
			else
			{
				gLandmarkList.makeCallbacks(uuid);
			}
		}
	}
	else
	{
		// SJB: No use case for a notification here. Use LL_DEBUGS() instead
		if( LL_ERR_ASSET_REQUEST_NOT_IN_DATABASE == status )
		{
			LL_WARNS("Landmarks") << "Missing Landmark" << LL_ENDL;
			//LLNotificationsUtil::add("LandmarkMissing");
		}
		else
		{
			LL_WARNS("Landmarks") << "Unable to load Landmark" << LL_ENDL;
			//LLNotificationsUtil::add("UnableToLoadLandmark");
		}

		gLandmarkList.mBadList.insert(uuid);
        gLandmarkList.mRequestedList.erase(uuid); //mBadList effectively blocks any load, so no point keeping id in requests
        // todo: this should clean mLoadedCallbackMap!
	}

    // getAssetData can fire callback immediately, causing
    // a recursion which is suboptimal for very large wait list.
    // 'scheduling' indicates that we are inside request and
    // shouldn't be launching more requests.
    static bool scheduling = false;
    if (!scheduling && !gLandmarkList.mWaitList.empty())
    {
        scheduling = true;
        while (!gLandmarkList.mWaitList.empty() && gLandmarkList.mRequestedList.size() < MAX_SIMULTANEOUS_REQUESTS)
        {
            // start new download from wait list
            landmark_uuid_list_t::iterator iter = gLandmarkList.mWaitList.begin();
            LLUUID asset_uuid = *iter;
            gLandmarkList.mWaitList.erase(iter);

            // add to mRequestedList before calling getAssetData()
            gLandmarkList.mRequestedList[asset_uuid] = gFrameTimeSeconds;

            // Note that getAssetData can callback immediately and cleans mRequestedList
            gAssetStorage->getAssetData(asset_uuid,
                LLAssetType::AT_LANDMARK,
                LLLandmarkList::processGetAssetReply,
                NULL);
        }
        scheduling = false;
    }
}

BOOL LLLandmarkList::isAssetInLoadedCallbackMap(const LLUUID& asset_uuid)
{
	return mLoadedCallbackMap.find(asset_uuid) != mLoadedCallbackMap.end();
}

BOOL LLLandmarkList::assetExists(const LLUUID& asset_uuid)
{
	return mList.count(asset_uuid) != 0 || mBadList.count(asset_uuid) != 0;
}

void LLLandmarkList::onRegionHandle(const LLUUID& landmark_id)
{
	LLLandmark* landmark = getAsset(landmark_id);

	if (!landmark)
	{
		LL_WARNS() << "Got region handle but the landmark not found." << LL_ENDL;
		return;
	}

	// Calculate landmark global position.
	// This should succeed since the region handle is available.
	LLVector3d pos;
	if (!landmark->getGlobalPos(pos))
	{
		LL_WARNS() << "Got region handle but the landmark global position is still unknown." << LL_ENDL;
		return;
	}

	makeCallbacks(landmark_id);
}

void LLLandmarkList::makeCallbacks(const LLUUID& landmark_id)
{
	LLLandmark* landmark = getAsset(landmark_id);

	if (!landmark)
	{
		LL_WARNS() << "Landmark to make callbacks for not found." << LL_ENDL;
	}

	// make all the callbacks here.
	loaded_callback_map_t::iterator it;
	while((it = mLoadedCallbackMap.find(landmark_id)) != mLoadedCallbackMap.end())
	{
		if (landmark)
			(*it).second(landmark);

		mLoadedCallbackMap.erase(it);
	}
}