/*

* Copyright (c) 2010 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description: 

*

*/

#include "cpixhits.h"

#include "idxdb.h"

#include "cpixexc.h"

#include "iqrytype.h"

#include "document.h"

#include "common/cpixlog.h"

namespace Cpix

{

    /**

     * Interface IHits

     */

    IHits::~IHits() 

    {

	;

    }

    void HitsBase::destroyWrappers()

    {

        WrapperMap::iterator

            i = wrappers_.begin(),

            end = wrappers_.end();

        for (; i != end; ++i)

            {

                delete i->second;

            }

        wrappers_.clear();

    }

    HitsBase::HitsBase(bool docsOwnedByClucene)

        : docsOwnedByClucene_(docsOwnedByClucene)

    {

        ;

    }

    void HitsBase::wrapDocument(int32_t                      index,

                                lucene::document::Document * doc)

    {

        if (wrappers_.find(index) != wrappers_.end())

            {

                delete wrappers_[index];

                wrappers_[index] = NULL;

            }

        Cpix::Document

            * cpixDoc = new Cpix::Document(doc,

                                           docsOwnedByClucene_);

        wrappers_[index] = cpixDoc;

    }

    Cpix::Document * HitsBase::getDocument(int32_t index)

    {

        Cpix::Document

            * rv = NULL;

        if (wrappers_.find(index) == wrappers_.end())

            {

                getDocument_(index);

            }

        rv = wrappers_[index];

        return rv;

    }

    /**

     * Class ClhDocumentConsumer

     */

    int32_t ClhDocumentConsumer::beginIndex() const

    {

        return beginIndex_;

    }

    int32_t ClhDocumentConsumer::endIndex() const

    {

        return endIndex_;

    }

    void ClhDocumentConsumer::useDocument(int32_t                      index,

                                          lucene::document::Document * document)

    {

        clHits_.wrapDocument(index,

                             document);

    }

    void ClhDocumentConsumer::failedDocument(int32_t        index,

                                             int            clErrorNumber)

    {

        failedDocErrors_[index - beginIndex_] = clErrorNumber;

    }

    ClhDocumentConsumer::ClhDocumentConsumer(LuceneHits & clHits)

        : pageSize_(IdxDbMgr::instance()->getClHitsPageSize()),

          beginIndex_(UNUSED),

          endIndex_(UNUSED),

          clHits_(clHits)

    {

        failedDocErrors_.reserve(pageSize_);

        for (int i = 0; i < pageSize_; ++i)

            {

                failedDocErrors_.push_back(CL_ERR_UNKNOWN);

            }

    }

    void ClhDocumentConsumer::setPageBoundaryForIndex(int32_t index)

    {

        if (index >= clHits_.length())

            {

                THROW_CPIXEXC("Not a valid hit doc: %d (hits length is %d)",

                              index,

                              clHits_.length());

            }

        beginIndex_ = index - (index % pageSize_);

        endIndex_ = beginIndex_ + pageSize_;

        endIndex_ = std::min(clHits_.length(),

                             endIndex_);

        for (int i = 0; i < pageSize_; ++i)

            {

                failedDocErrors_[i] = CL_ERR_UNKNOWN;

            }

    }

    void ClhDocumentConsumer::throwIfFailedDocIndex(int32_t index)

    {

        if (beginIndex_ == UNUSED)

            {

                // nothing has been fetched with this instance, so

                // nothing has failed yet

                return;

            }

        if (index < beginIndex_ || index >= endIndex_)

            {

                // we have not tried to load this document in this

                // batch

                return;

            }

        int32_t

            idx = index - beginIndex_;

        if (failedDocErrors_[idx] != CL_ERR_Success)

            {

                THROW_CPIXEXC("Failed to fetch hit document %d, CL error code: %d (cf. clucene debug/error.h)",

                              index,

                              failedDocErrors_[idx]);

            }

        else

            {

                THROW_CPIXEXC(PL_ERROR "Reloading a document should not be necessary %d",

                              index);

            }

    }

    /**

     * Class LuceneHits wrapping lucene::document::Hits

     */

    LuceneHits::LuceneHits(lucene::search::Hits  * hits, 

                             lucene::search::Query * query,

                             IdxDbHndl               idxDb,

                             Version                 idxDbVersion)

	: HitsBase(true), // docs in here are owned by clucene

          hits_(hits),

          length_(hits != NULL ? hits->length() : 0),

	  query_(query),  // increase reference count

          idxDb_(idxDb),

          idxDbVersion_(idxDbVersion),

          docConsumer_(NULL)

    {

        docConsumer_ = new ClhDocumentConsumer(*this);

        IdxDbMgr::instance()->incRefHndl(idxDb_);

        // pre-fetching the first page - assumption is that first

        // document to get will be #0 anyway, and no need for IPC +

        // ctxt switch with client by which time an idx operation may

        // have upset everything.

        //

        // TODO the dependent idxdb locks are released by this point,

        // so getDocument_ will have to re-acquire all locks, which is

        // not only OS operation but may bump into already modified

        // idx-es. Idea: IIdxDb::search could be reorganized into

        // fetchRecommitting() instead - the first fetch operations

        // would be performed while locks are still in place...

        if (length_ > 0)

            {

                getDocument_(0);

            }

    }

    LuceneHits::~LuceneHits() 

    {

        delete hits_; 

        hits_ = 0; 

        destroyWrappers();

        delete docConsumer_;

        IdxDbMgr::instance()->releaseHndl(idxDb_);

    }

    void LuceneHits::getDocument_(int32_t index) 

    {

        // check if we have tried to fetch it before and failed

        docConsumer_->throwIfFailedDocIndex(index);

        // common usage pattern is to enumerate hits, never to access

        // them at true random manner. That means that we never need

        // wrappers for more than the current page - ie when about to

        // fetch the next page we can discard all other wrapped

        // documents. Merely an memory consumption optimization

        // measure, can be commented out.

        destroyWrappers();

        // if we get here, then it means we don't have the page of hit

        // docs we need, but it may still throw if the hits is an

        // empty object or the hits itself was NULL

        docConsumer_->setPageBoundaryForIndex(index);

        IIdxDb* idx = IIdxDb::getPtr( idxDb_ );

        lucene::search::Hits

            * currentHits = hits_;

        hits_ = 0;

        // the version number of idx that produced currentHits is

        // either still the same in which case we get back

        // currentHits, or it has changed and in that case currentHits

        // will be destroyed by this call and a new one will be

        // returned - rv will recieve the pointer to the fetched document

        hits_ = idx->fetchRecommitting(currentHits,

                                       &idxDbVersion_,

                                       query_,

                                       *docConsumer_);

        length_ = hits_->length();

        if (wrappers_.find(index) == wrappers_.end())

            {

                THROW_CPIXEXC("Failed to fetch doc %d: TODO reason",

                              index);

            }

    }

    int32_t LuceneHits::length()

    {

        return length_;

    }

    /**

     * HitDocumentList (for suggestion feature)

     */

    HitDocumentList::HitDocumentList()

	: HitsBase(false) // docs owned by this

    {

        ;

    }

    HitDocumentList::~HitDocumentList()

    {

        destroyWrappers();

        for (std::vector<lucene::document::Document*>::iterator i = documents_.begin(); 

             i != documents_.end(); 

             i++) 

            {

                _CLDELETE(*i); 

            }

    }

    void HitDocumentList::getDocument_(int32_t index)

    {

        if (index >= 0 && index < documents_.size()) 

            {

                wrapDocument(index,

                             documents_[index]);

            }

        else 

            {

                THROW_CPIXEXC(L"Hit document index '%d' out of bounds",

                              index);

            }

    }

    int32_t HitDocumentList::length()

    {

        return documents_.size(); 

    }

    void HitDocumentList::add(lucene::document::Document* document)

    {

        documents_.push_back(document); 

    }

    void HitDocumentList::remove(int index)

    {

        documents_.erase(documents_.begin()+index); 

    }

}