/**************************************************************
 * 
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 * 
 *************************************************************/


// MARKER(update_precomp.py): autogen include statement, do not remove
#include "precompiled_canvas.hxx"

#include <boost/bind.hpp>
#include "pagemanager.hxx"

namespace canvas
{

	//////////////////////////////////////////////////////////////////////////////////
	// PageManager
	//////////////////////////////////////////////////////////////////////////////////

	//////////////////////////////////////////////////////////////////////////////////
	// PageManager::allocateSpace
	//////////////////////////////////////////////////////////////////////////////////

	FragmentSharedPtr PageManager::allocateSpace( const ::basegfx::B2ISize& rSize )
	{
		// we are asked to find a location for the requested size.
		// first we try to satisfy the request from the
		// remaining space in the existing pages.
		const PageContainer_t::iterator aEnd(maPages.end());
		PageContainer_t::iterator       it(maPages.begin());
		while(it != aEnd)
		{
			FragmentSharedPtr pFragment((*it)->allocateSpace(rSize));
			if(pFragment)
			{
				// the page created a new fragment, since we maybe want
				// to consolidate sparse pages we keep a reference to
				// the fragment.
				maFragments.push_back(pFragment);
				return pFragment;
			}

			++it;
		}

		// otherwise try to create a new page and allocate space there...
		PageSharedPtr pPage(new Page(mpRenderModule));
		if(pPage->isValid())
		{
			maPages.push_back(pPage);
			FragmentSharedPtr pFragment(pPage->allocateSpace(rSize));
            if (pFragment)
                maFragments.push_back(pFragment);
			return pFragment;
		}

		// the rendermodule failed to create a new page [maybe out
		// of videomemory], and all other pages could not take
		// the new request. we decide to create a 'naked' fragment
		// which will receive its location later.
		FragmentSharedPtr pFragment(new PageFragment(rSize));
		maFragments.push_back(pFragment);
		return pFragment;
	}

	//////////////////////////////////////////////////////////////////////////////////
	// PageManager::free
	//////////////////////////////////////////////////////////////////////////////////
	
	void PageManager::free( const FragmentSharedPtr& pFragment )
	{
		// erase the reference to the given fragment from our
		// internal container.
		FragmentContainer_t::iterator it(
			std::remove(
				maFragments.begin(),maFragments.end(),pFragment));
		maFragments.erase(it,maFragments.end());

		// let the fragment itself know about it...
		// we need to pass 'this' as argument since the fragment
		// needs to pass this to the page and can't create
		// shared_ptr from itself...
		pFragment->free(pFragment);
    }

	//////////////////////////////////////////////////////////////////////////////////
	// PageManager::nakedFragment
	//////////////////////////////////////////////////////////////////////////////////

	void PageManager::nakedFragment( const FragmentSharedPtr& pFragment )
	{
		if(maPages.empty())
			return;

		// okay, one last chance is left, we try all available
		// pages again. maybe some other fragment was deleted
		// and we can exploit the space.
		while(!(relocate(pFragment)))
		{
			// no way, we need to free up some space...
			// TODO(F1): this is a heuristic, could
			// be designed as a policy.
			const FragmentContainer_t::const_iterator aEnd(maFragments.end());
			FragmentContainer_t::const_iterator       candidate(maFragments.begin());
			while(candidate != aEnd)
			{
				if(*candidate && !((*candidate)->isNaked()))
					break;
				++candidate;
			}

            if (candidate != aEnd)
            {
                const ::basegfx::B2ISize& rSize((*candidate)->getSize());
                sal_uInt32                nMaxArea(rSize.getX()*rSize.getY());

                FragmentContainer_t::const_iterator it(candidate);
                while(it != aEnd)
                {
                    if (*it && !((*it)->isNaked()))
                    {
                        const ::basegfx::B2ISize& rCandidateSize((*it)->getSize());
                        const sal_uInt32 nArea(rCandidateSize.getX()*rCandidateSize.getY());
                        if(nArea > nMaxArea)
                        {
                            candidate=it;
                            nMaxArea=nArea;
                        }
                    }

                    ++it;
                }

                // this does not erase the candidate,
                // but makes it 'naked'...
                (*candidate)->free(*candidate);
            }
            else
                break;
		}
	}

	//////////////////////////////////////////////////////////////////////////////////
	// PageManager::relocate
	//////////////////////////////////////////////////////////////////////////////////

	bool PageManager::relocate( const FragmentSharedPtr& pFragment )
	{
		// the fragment passed as argument is assumed to
		// be naked, that is it is not located on any page.
		// we try all available pages again, maybe some
		// other fragment was deleted and we can exploit the space.
		const PageContainer_t::iterator aEnd(maPages.end());
		PageContainer_t::iterator       it(maPages.begin());
		while(it != aEnd)
		{
			// if the page at hand takes the fragment, we immediately
			// call select() to pull the information from the associated
			// image to the hardware surface.
			if((*it)->nakedFragment(pFragment))
			{
				// dirty, since newly allocated.
				pFragment->select(true);
				return true;
			}

			++it;
		}

		return false;
	}

	//////////////////////////////////////////////////////////////////////////////////
	// PageManager::validatePages
	//////////////////////////////////////////////////////////////////////////////////
	
	void PageManager::validatePages()
	{
		::std::for_each( maPages.begin(),
                         maPages.end(),
						 ::boost::mem_fn(&Page::validate));
	}

	//////////////////////////////////////////////////////////////////////////////////
	// PageManager::getPageSize
	//////////////////////////////////////////////////////////////////////////////////

	::basegfx::B2ISize PageManager::getPageSize() const
	{
		return mpRenderModule->getPageSize();
	}

	//////////////////////////////////////////////////////////////////////////////////
	// PageManager::getRenderModule
	//////////////////////////////////////////////////////////////////////////////////
	
	canvas::IRenderModuleSharedPtr PageManager::getRenderModule() const
	{
		return mpRenderModule;
	}
}