/*
 * KDevelop Generic Code Completion Support
 *
 * Copyright 2006-2008 Hamish Rodda <rodda@kde.org>
 * Copyright 2007-2008 David Nolden <david.nolden.kdevelop@art-master.de>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Library General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */

#include "codecompletionmodel.h"

#include <QThread>
#include <KTextEditor/View>
#include <KTextEditor/Document>

#include "../duchain/declaration.h"
#include "../duchain/classfunctiondeclaration.h"
#include "../duchain/ducontext.h"
#include "../duchain/duchain.h"
#include "../duchain/namespacealiasdeclaration.h"
#include "../duchain/parsingenvironment.h"
#include "../duchain/duchainlock.h"
#include "../duchain/duchainbase.h"
#include "../duchain/topducontext.h"
#include "../duchain/duchainutils.h"
#include "../interfaces/quickopendataprovider.h"
#include "../interfaces/icore.h"
#include "../interfaces/ilanguagecontroller.h"
#include "../interfaces/icompletionsettings.h"
#include <debug.h>

#include "codecompletionworker.h"
#include "codecompletioncontext.h"
#include <duchain/specializationstore.h>

using namespace KTextEditor;

//Multi-threaded completion creates some multi-threading related crashes, and sometimes shows the completions in the wrong position if the cursor was moved
// #define SINGLE_THREADED_COMPLETION

namespace KDevelop {

class CompletionWorkerThread : public QThread
{
   Q_OBJECT
public:

   explicit CompletionWorkerThread(CodeCompletionModel* model)
     : QThread(model), m_model(model), m_worker(m_model->createCompletionWorker())
   {
     Q_ASSERT(m_worker->parent() == nullptr); // Must be null, else we cannot change the thread affinity!
     m_worker->moveToThread(this);
     Q_ASSERT(m_worker->thread() == this);
   }

   ~CompletionWorkerThread() override {
     delete m_worker;
   }

   void run () override {
     //We connect directly, so we can do the pre-grouping within the background thread
     connect(m_worker, &CodeCompletionWorker::foundDeclarationsReal, m_model, &CodeCompletionModel::foundDeclarations, Qt::QueuedConnection);

     connect(m_model, &CodeCompletionModel::completionsNeeded, m_worker, static_cast<void(CodeCompletionWorker::*)(const DUChainPointer<KDevelop::DUContext>&, const Cursor&, View*)>(&CodeCompletionWorker::computeCompletions), Qt::QueuedConnection);
     connect(m_model, &CodeCompletionModel::doSpecialProcessingInBackground, m_worker, &CodeCompletionWorker::doSpecialProcessing);
     exec();
   }

   CodeCompletionModel* m_model;
   CodeCompletionWorker* m_worker;
};

bool CodeCompletionModel::forceWaitForModel()
{
  return m_forceWaitForModel;
}

void CodeCompletionModel::setForceWaitForModel(bool wait)
{
  m_forceWaitForModel = wait;
}


CodeCompletionModel::CodeCompletionModel( QObject * parent )
  : KTextEditor::CodeCompletionModel(parent)
  , m_forceWaitForModel(false)
  , m_fullCompletion(true)
  , m_mutex(new QMutex)
  , m_thread(nullptr)
{
  qRegisterMetaType<KTextEditor::Cursor>();
}

void CodeCompletionModel::initialize() {
  if(!m_thread) {
    m_thread = new CompletionWorkerThread(this);
#ifdef SINGLE_THREADED_COMPLETION
    m_thread->m_worker = createCompletionWorker();
#endif
    m_thread->start();
  }
}

CodeCompletionModel::~CodeCompletionModel()
{
  if(m_thread->m_worker)
    m_thread->m_worker->abortCurrentCompletion();
  m_thread->quit();
  m_thread->wait();

  delete m_thread;
  delete m_mutex;
}

bool CodeCompletionModel::fullCompletion() const
{
  return m_fullCompletion;
}

KDevelop::CodeCompletionWorker* CodeCompletionModel::worker() const {
  return m_thread->m_worker;
}

void CodeCompletionModel::clear()
{
  beginResetModel();
  m_completionItems.clear();
  m_completionContext.reset();
  endResetModel();
}

void CodeCompletionModel::completionInvokedInternal(KTextEditor::View* view, const KTextEditor::Range& range, InvocationType invocationType, const QUrl& url)
{
  Q_ASSERT(m_thread == worker()->thread());
  Q_UNUSED(invocationType)

  DUChainReadLocker lock(DUChain::lock(), 400);
  if( !lock.locked() ) {
    qCDebug(LANGUAGE) << "could not lock du-chain in time";
    return;
  }

  TopDUContext* top = DUChainUtils::standardContextForUrl( url );
  if(!top) {
    qCDebug(LANGUAGE) << "================== NO CONTEXT FOUND =======================";
    beginResetModel();
    m_completionItems.clear();
    endResetModel();

    qCDebug(LANGUAGE) << "Completion invoked for unknown context. Document:" << url << ", Known documents:" << DUChain::self()->documents();

    return;
  }

  setCurrentTopContext(TopDUContextPointer(top));

  RangeInRevision rangeInRevision = top->transformToLocalRevision(KTextEditor::Range(range));

  qCDebug(LANGUAGE) << "completion invoked for context" << (DUContext*)top;

  if( top->parsingEnvironmentFile() && top->parsingEnvironmentFile()->modificationRevision() != ModificationRevision::revisionForFile(IndexedString(url.toString())) ) {
      qCDebug(LANGUAGE) << "Found context is not current.";
  }

  DUContextPointer thisContext;
  {
    qCDebug(LANGUAGE) << "apply specialization:" << range.start();
    thisContext = SpecializationStore::self().applySpecialization(top->findContextAt(rangeInRevision.start), top);

    if ( thisContext ) {
      qCDebug(LANGUAGE) << "after specialization:" << thisContext->localScopeIdentifier().toString() << thisContext->rangeInCurrentRevision();
    } else {
      thisContext = top;
    }

    qCDebug(LANGUAGE) << "context is set to" << thisContext.data();
  }

  lock.unlock();

  if(m_forceWaitForModel)
    emit waitForReset();

  emit completionsNeeded(thisContext, range.start(), view);
}


void CodeCompletionModel::completionInvoked(KTextEditor::View* view, const KTextEditor::Range& range, InvocationType invocationType)
{
  //If this triggers, initialize() has not been called after creation.
  Q_ASSERT(m_thread);

  KDevelop::ICompletionSettings::CompletionLevel level = KDevelop::ICore::self()->languageController()->completionSettings()->completionLevel();
  if(level == KDevelop::ICompletionSettings::AlwaysFull || (invocationType != AutomaticInvocation && level == KDevelop::ICompletionSettings::MinimalWhenAutomatic))
    m_fullCompletion = true;
  else
    m_fullCompletion = false;

  //Only use grouping in full completion mode
  setHasGroups(m_fullCompletion);

  Q_UNUSED(invocationType)

  if (!worker()) {
    qCWarning(LANGUAGE) << "Completion invoked on a completion model which has no code completion worker assigned!";
  }

  beginResetModel();
  m_completionItems.clear();
  endResetModel();

  worker()->abortCurrentCompletion();
  worker()->setFullCompletion(m_fullCompletion);

  QUrl url = view->document()->url();

  completionInvokedInternal(view, range, invocationType, url);
}

void CodeCompletionModel::foundDeclarations(const QList<QExplicitlySharedDataPointer<CompletionTreeElement>>& items,
                                            const QExplicitlySharedDataPointer<CodeCompletionContext>& completionContext)
{
  m_completionContext = completionContext;

  if(m_completionItems.isEmpty() && items.isEmpty()) {
    if(m_forceWaitForModel) {
      // TODO KF5: Check if this actually works
      beginResetModel();
      endResetModel(); //If we need to reset the model, reset it
    }
    return; //We don't need to reset, which is bad for target model
  }

  beginResetModel();
  m_completionItems = items;
  endResetModel();

  if(m_completionContext) {
    qCDebug(LANGUAGE) << "got completion-context with " << m_completionContext->ungroupedElements().size() << "ungrouped elements";
  }
}

KTextEditor::CodeCompletionModelControllerInterface::MatchReaction CodeCompletionModel::matchingItem(const QModelIndex& /*matched*/)
{
    return None;
}

void CodeCompletionModel::setCompletionContext(const QExplicitlySharedDataPointer<CodeCompletionContext>& completionContext)
{
  QMutexLocker lock(m_mutex);
  m_completionContext = completionContext;

  if(m_completionContext) {
    qCDebug(LANGUAGE) << "got completion-context with " << m_completionContext->ungroupedElements().size() << "ungrouped elements";
  }
}

QExplicitlySharedDataPointer<CodeCompletionContext> CodeCompletionModel::completionContext() const
{
  QMutexLocker lock(m_mutex);
  return m_completionContext;
}

void CodeCompletionModel::executeCompletionItem(View* view, const KTextEditor::Range& word, const QModelIndex& index) const
{
  //We must not lock the duchain at this place, because the items might rely on that
  CompletionTreeElement* element = static_cast<CompletionTreeElement*>(index.internalPointer());
  if( !element || !element->asItem() )
    return;

  element->asItem()->execute(view, word);
}

QExplicitlySharedDataPointer<KDevelop::CompletionTreeElement> CodeCompletionModel::itemForIndex(const QModelIndex& index) const
{
  CompletionTreeElement* element = static_cast<CompletionTreeElement*>(index.internalPointer());
  return QExplicitlySharedDataPointer< KDevelop::CompletionTreeElement >(element);
}

QVariant CodeCompletionModel::data(const QModelIndex& index, int role) const
{
  if ( role == Qt::TextAlignmentRole && index.column() == 0 ) {
    return Qt::AlignRight;
  }
  auto element = static_cast<const CompletionTreeElement*>(index.internalPointer());
  if( !element )
    return QVariant();

  if( role == CodeCompletionModel::GroupRole ) {
    if( element->asNode() ) {
      return QVariant(element->asNode()->role);
    }else {
      qCDebug(LANGUAGE) << "Requested group-role from leaf tree element";
      return QVariant();
    }
  }else{
    if( element->asNode() ) {
      if( role == CodeCompletionModel::InheritanceDepth ) {
        auto customGroupNode = dynamic_cast<const CompletionCustomGroupNode*>(element);
        if(customGroupNode)
          return QVariant(customGroupNode->inheritanceDepth);
      }
      if( role == element->asNode()->role ) {
        return element->asNode()->roleValue;
      } else {
        return QVariant();
      }
    }
  }

  if(!element->asItem()) {
    qCWarning(LANGUAGE) << "Error in completion model";
    return QVariant();
  }

  //Navigation widget interaction is done here, the other stuff is done within the tree-elements
  switch (role) {
    case CodeCompletionModel::InheritanceDepth:
      return element->asItem()->inheritanceDepth();
    case CodeCompletionModel::ArgumentHintDepth:
      return element->asItem()->argumentHintDepth();

    case CodeCompletionModel::ItemSelected: {
      DeclarationPointer decl = element->asItem()->declaration();
      if(decl) {
        DUChain::self()->emitDeclarationSelected(decl);
      }
      break;
    }
  }

  //In minimal completion mode, hide all columns except the "name" one
  if(!m_fullCompletion && role == Qt::DisplayRole && index.column() != Name && (element->asItem()->argumentHintDepth() == 0 || index.column() == Prefix))
    return QVariant();


  //In reduced completion mode, don't show information text with the selected items
  if(role == ItemSelected && (!m_fullCompletion || !ICore::self()->languageController()->completionSettings()->showMultiLineSelectionInformation()))
    return QVariant();

  return element->asItem()->data(index, role, this);
}

KDevelop::TopDUContextPointer CodeCompletionModel::currentTopContext() const
{
  return m_currentTopContext;
}

void CodeCompletionModel::setCurrentTopContext(const KDevelop::TopDUContextPointer& topContext)
{
  m_currentTopContext = topContext;
}

QModelIndex CodeCompletionModel::index(int row, int column, const QModelIndex& parent) const
{
  if( parent.isValid() ) {
    CompletionTreeElement* element = static_cast<CompletionTreeElement*>(parent.internalPointer());

    CompletionTreeNode* node = element->asNode();

    if( !node ) {
      qCDebug(LANGUAGE) << "Requested sub-index of leaf node";
      return QModelIndex();
    }

    if (row < 0 || row >= node->children.count() || column < 0 || column >= ColumnCount)
      return QModelIndex();

    return createIndex(row, column, node->children[row].data());
  } else {
    if (row < 0 || row >= m_completionItems.count() || column < 0 || column >= ColumnCount)
      return QModelIndex();

    return createIndex(row, column, const_cast<CompletionTreeElement*>(m_completionItems[row].data()));
  }
}

QModelIndex CodeCompletionModel::parent ( const QModelIndex & index ) const
{
  if(rowCount() == 0)
    return QModelIndex();

  if( index.isValid() ) {
    CompletionTreeElement* element = static_cast<CompletionTreeElement*>(index.internalPointer());

    if( element->parent() )
      return createIndex( element->rowInParent(), element->columnInParent(), element->parent() );
  }

  return QModelIndex();
}

int CodeCompletionModel::rowCount ( const QModelIndex & parent ) const
{
  if( parent.isValid() ) {
    CompletionTreeElement* element = static_cast<CompletionTreeElement*>(parent.internalPointer());

    CompletionTreeNode* node = element->asNode();

    if( !node )
      return 0;

    return node->children.count();
  }else{
    return m_completionItems.count();
  }
}

QString CodeCompletionModel::filterString(KTextEditor::View* view, const KTextEditor::Range& range, const KTextEditor::Cursor& position)
{
  m_filterString = KTextEditor::CodeCompletionModelControllerInterface::filterString(view, range, position);
  return m_filterString;
}

}

#include "moc_codecompletionmodel.cpp"
#include "codecompletionmodel.moc"
