/*  This file is part of the KDE libraries and the Kate part.
 *
 *  Copyright (C) 2005 Hamish Rodda <rodda@kde.org>
 *  Copyright (C) 2008 Dominik Haumann <dhaumann kde org>
 *
 *  This library 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 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
 *  Library General Public License for more details.
 *
 *  You should have received a copy of the GNU Library General Public License
 *  along with this library; see the file COPYING.LIB.  If not, write to
 *  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 *  Boston, MA 02110-1301, USA.
 */

#include "katelayoutcache.h"
#include "moc_katelayoutcache.cpp"

#include <QtCore/qalgorithms.h>

#include "katerenderer.h"
#include "kateview.h"
#include "katedocument.h"
#include "katebuffer.h"

static bool enableLayoutCache = false;

//BEGIN KateLineLayoutMap
KateLineLayoutMap::KateLineLayoutMap()
{
}

KateLineLayoutMap::~KateLineLayoutMap()
{
}

bool lessThan(const KateLineLayoutMap::LineLayoutPair& lhs,
              const KateLineLayoutMap::LineLayoutPair& rhs)
{
  return lhs.first < rhs.first;
}

void KateLineLayoutMap::clear()
{
  m_lineLayouts.clear();
}

bool KateLineLayoutMap::contains(int i) const
{
  LineLayoutMap::const_iterator it =
    qBinaryFind(m_lineLayouts.constBegin(), m_lineLayouts.constEnd(), LineLayoutPair(i,KateLineLayoutPtr()), lessThan);
  return (it != m_lineLayouts.constEnd());
}

void KateLineLayoutMap::insert(int realLine, const KateLineLayoutPtr& lineLayoutPtr)
{
  LineLayoutMap::iterator it =
    qBinaryFind(m_lineLayouts.begin(), m_lineLayouts.end(), LineLayoutPair(realLine,KateLineLayoutPtr()), lessThan);
  if (it != m_lineLayouts.end()) {
    (*it).second = lineLayoutPtr;
  } else {
    it = qUpperBound(m_lineLayouts.begin(), m_lineLayouts.end(), LineLayoutPair(realLine,KateLineLayoutPtr()), lessThan);
    m_lineLayouts.insert(it, LineLayoutPair(realLine, lineLayoutPtr));
  }
}

void KateLineLayoutMap::viewWidthIncreased()
{
  LineLayoutMap::iterator it = m_lineLayouts.begin();
  for ( ; it != m_lineLayouts.end(); ++it) {
    if ((*it).second->isValid() && (*it).second->viewLineCount() > 1)
      (*it).second->invalidateLayout();
  }
}

void KateLineLayoutMap::viewWidthDecreased(int newWidth)
{
  LineLayoutMap::iterator it = m_lineLayouts.begin();
  for ( ; it != m_lineLayouts.end(); ++it) {
    if ((*it).second->isValid()
        && ((*it).second->viewLineCount() > 1 || (*it).second->width() > newWidth))
      (*it).second->invalidateLayout();
  }
}

void KateLineLayoutMap::relayoutLines(int startRealLine, int endRealLine)
{
  LineLayoutMap::iterator start =
      qLowerBound(m_lineLayouts.begin(), m_lineLayouts.end(), LineLayoutPair(startRealLine, KateLineLayoutPtr()), lessThan);
  LineLayoutMap::iterator end =
      qUpperBound(start, m_lineLayouts.end(), LineLayoutPair(endRealLine, KateLineLayoutPtr()), lessThan);

  while (start != end) {
    (*start).second->setLayoutDirty();
    ++start;
  }
}

void KateLineLayoutMap::slotEditDone(int fromLine, int toLine, int shiftAmount)
{
  LineLayoutMap::iterator start =
      qLowerBound(m_lineLayouts.begin(), m_lineLayouts.end(), LineLayoutPair(fromLine, KateLineLayoutPtr()), lessThan);
  LineLayoutMap::iterator end =
      qUpperBound(start, m_lineLayouts.end(), LineLayoutPair(toLine, KateLineLayoutPtr()), lessThan);
  LineLayoutMap::iterator it;

  if (shiftAmount != 0) {
    for (it = end; it != m_lineLayouts.end(); ++it) {
      (*it).first += shiftAmount;
      (*it).second->setLine((*it).second->line() + shiftAmount);
    }

    for (it = start; it != end; ++it) {
      (*it).second->clear();
    }

    m_lineLayouts.erase(start, end);
  } else {
    for (it = start; it != end; ++it) {
      (*it).second->setLayoutDirty();
    }
  }
}


KateLineLayoutPtr& KateLineLayoutMap::operator[](int i)
{
  LineLayoutMap::iterator it =
    qBinaryFind(m_lineLayouts.begin(), m_lineLayouts.end(), LineLayoutPair(i, KateLineLayoutPtr()), lessThan);
  return (*it).second;
}
//END KateLineLayoutMap

KateLayoutCache::KateLayoutCache(KateRenderer* renderer, QObject* parent)
  : QObject(parent)
  , m_renderer(renderer)
  , m_startPos(-1,-1)
  , m_viewWidth(0)
  , m_wrap(false)
  , m_acceptDirtyLayouts (false)
{
  Q_ASSERT(m_renderer);
  
  /**
   * connect to all possible editing primitives
   */
  connect(&m_renderer->doc()->buffer(), SIGNAL(lineWrapped(KTextEditor::Cursor)), this, SLOT(wrapLine(KTextEditor::Cursor)));
  connect(&m_renderer->doc()->buffer(), SIGNAL(lineUnwrapped(int)), this, SLOT(unwrapLine(int)));
  connect(&m_renderer->doc()->buffer(), SIGNAL(textInserted(KTextEditor::Cursor,QString)), this, SLOT(insertText(KTextEditor::Cursor,QString)));
  connect(&m_renderer->doc()->buffer(), SIGNAL(textRemoved(KTextEditor::Range,QString)), this, SLOT(removeText(KTextEditor::Range)));
}

void KateLayoutCache::updateViewCache(const KTextEditor::Cursor& startPos, int newViewLineCount, int viewLinesScrolled)
{
  //kDebug( 13033 ) << startPos << " nvlc " << newViewLineCount << " vls " << viewLinesScrolled;

  int oldViewLineCount = m_textLayouts.count();
  if (newViewLineCount == -1)
    newViewLineCount = oldViewLineCount;

  enableLayoutCache = true;

  int realLine;
  if (newViewLineCount == -1)
    realLine = m_renderer->folding().visibleLineToLine(m_renderer->folding().lineToVisibleLine(startPos.line()));
  else
    realLine = m_renderer->folding().visibleLineToLine(startPos.line());
  int _viewLine = 0;

  if (wrap()) {
    // TODO check these assumptions are ok... probably they don't give much speedup anyway?
    if (startPos == m_startPos && m_textLayouts.count()) {
      _viewLine = m_textLayouts.first().viewLine();

    } else if (viewLinesScrolled > 0 && viewLinesScrolled < m_textLayouts.count()) {
      _viewLine = m_textLayouts[viewLinesScrolled].viewLine();

    } else {
      KateLineLayoutPtr l = line(realLine);
      if (l) {
        Q_ASSERT(l->isValid());
        Q_ASSERT(l->length() >= startPos.column() || m_renderer->view()->wrapCursor());

        for (; _viewLine < l->viewLineCount(); ++_viewLine) {
          const KateTextLayout& t = l->viewLine(_viewLine);
          if (t.startCol() >= startPos.column() || _viewLine == l->viewLineCount() - 1)
            goto foundViewLine;
        }

        // FIXME FIXME need to calculate past-end-of-line position here...
        Q_ASSERT(false);

        foundViewLine:
        Q_ASSERT(true);
      }
    }
  }

  m_startPos = startPos;

  // Move the text layouts if we've just scrolled...
  if (viewLinesScrolled != 0) {
    // loop backwards if we've just scrolled up...
    bool forwards = viewLinesScrolled >= 0 ? true : false;
    for (int z = forwards ? 0 : m_textLayouts.count() - 1; forwards ? (z < m_textLayouts.count()) : (z >= 0); forwards ? z++ : z--) {
      int oldZ = z + viewLinesScrolled;
      if (oldZ >= 0 && oldZ < m_textLayouts.count())
        m_textLayouts[z] = m_textLayouts[oldZ];
    }
  }

  // Resize functionality
  if (newViewLineCount > oldViewLineCount) {
    m_textLayouts.reserve(newViewLineCount);

  } else if (newViewLineCount < oldViewLineCount) {
    /* FIXME reintroduce... check we're not missing any
    int lastLine = m_textLayouts[newSize - 1].line();
    for (int i = oldSize; i < newSize; i++) {
      const KateTextLayout& layout = m_textLayouts[i];
      if (layout.line() > lastLine && !layout.viewLine())
        layout.kateLineLayout()->layout()->setCacheEnabled(false);
    }*/
    m_textLayouts.resize(newViewLineCount);
  }

  KateLineLayoutPtr l = line(realLine);
  for (int i = 0; i < newViewLineCount; ++i) {
    if (!l) {
      if (i < m_textLayouts.count()) {
        if (m_textLayouts[i].isValid())
          m_textLayouts[i] = KateTextLayout::invalid();
      } else {
        m_textLayouts.append(KateTextLayout::invalid());
      }
      continue;
    }

    Q_ASSERT(l->isValid());
    Q_ASSERT(_viewLine < l->viewLineCount());

    if (i < m_textLayouts.count()) {
      bool dirty = false;
      if (m_textLayouts[i].line() != realLine || m_textLayouts[i].viewLine() != _viewLine || (!m_textLayouts[i].isValid() && l->viewLine(_viewLine).isValid()))
        dirty = true;
      m_textLayouts[i] = l->viewLine(_viewLine);
      if (dirty)
        m_textLayouts[i].setDirty(true);

    } else {
      m_textLayouts.append(l->viewLine(_viewLine));
    }

    //kDebug( 13033 ) << "Laid out line " << realLine << " (" << l << "), viewLine " << _viewLine << " (" << m_textLayouts[i].kateLineLayout().data() << ")";
    //m_textLayouts[i].debugOutput();

    _viewLine++;

    if (_viewLine > l->viewLineCount() - 1) {
      int virtualLine = l->virtualLine() + 1;
      realLine = m_renderer->folding().visibleLineToLine(virtualLine);
      _viewLine = 0;
      if (realLine < m_renderer->doc()->lines()) {
        l = line(realLine, virtualLine);
      } else {
        l = 0;
      }
    }
  }

  enableLayoutCache = false;
}

KateLineLayoutPtr KateLayoutCache::line( int realLine, int virtualLine )
{
  if (m_lineLayouts.contains(realLine)) {
    KateLineLayoutPtr l = m_lineLayouts[realLine];
    
    // ensure line is OK
    Q_ASSERT (l->line() == realLine);
    Q_ASSERT (realLine < m_renderer->doc()->buffer().lines());

    if (virtualLine != -1)
      l->setVirtualLine(virtualLine);

    if (!l->isValid())
    {
      l->setUsePlainTextLine (acceptDirtyLayouts());
      l->textLine (!acceptDirtyLayouts());
      m_renderer->layoutLine(l, wrap() ? m_viewWidth : -1, enableLayoutCache);
    }
    else if (l->isLayoutDirty() && !acceptDirtyLayouts())
    {
      // reset textline
      l->setUsePlainTextLine (false);
      l->textLine (true);
      m_renderer->layoutLine(l, wrap() ? m_viewWidth : -1, enableLayoutCache);
    }

    Q_ASSERT(l->isValid() && (!l->isLayoutDirty() || acceptDirtyLayouts()));

    return l;
  }

  if (realLine < 0 || realLine >= m_renderer->doc()->lines())
    return KateLineLayoutPtr();

  KateLineLayoutPtr l(new KateLineLayout(*m_renderer));
  l->setLine(realLine, virtualLine);

  // Mark it dirty, because it may not have the syntax highlighting applied
  // mark this here, to allow layoutLine to use plainLines...
  if (acceptDirtyLayouts())
    l->setUsePlainTextLine (true);

  m_renderer->layoutLine(l, wrap() ? m_viewWidth : -1, enableLayoutCache);
  Q_ASSERT(l->isValid());

  if (acceptDirtyLayouts())
    l->setLayoutDirty (true);

  m_lineLayouts.insert(realLine, l);
  return l;
}

KateLineLayoutPtr KateLayoutCache::line( const KTextEditor::Cursor & realCursor )
{
  return line(realCursor.line());
}

KateTextLayout KateLayoutCache::textLayout( const KTextEditor::Cursor & realCursor )
{
  /*if (realCursor >= viewCacheStart() && (realCursor < viewCacheEnd() || realCursor == viewCacheEnd() && !m_textLayouts.last().wrap()))
    foreach (const KateTextLayout& l, m_textLayouts)
      if (l.line() == realCursor.line() && (l.endCol() < realCursor.column() || !l.wrap()))
        return l;*/

  return line(realCursor.line())->viewLine(viewLine(realCursor));
}

KateTextLayout KateLayoutCache::textLayout( uint realLine, int _viewLine )
{
  /*if (m_textLayouts.count() && (realLine >= m_textLayouts.first().line() && _viewLine >= m_textLayouts.first().viewLine()) &&
      (realLine <= m_textLayouts.last().line() && _viewLine <= m_textLayouts.first().viewLine()))
    foreach (const KateTextLayout& l, m_textLayouts)
      if (l.line() == realLine && l.viewLine() == _viewLine)
        return const_cast<KateTextLayout&>(l);*/

  return line(realLine)->viewLine(_viewLine);
}

KateTextLayout & KateLayoutCache::viewLine( int _viewLine )
{
  Q_ASSERT(_viewLine >= 0 && _viewLine < m_textLayouts.count());
  return m_textLayouts[_viewLine];
}

int KateLayoutCache::viewCacheLineCount( ) const
{
  return m_textLayouts.count();
}

KTextEditor::Cursor KateLayoutCache::viewCacheStart( ) const
{
  return m_textLayouts.count() ? m_textLayouts.first().start() : KTextEditor::Cursor();
}

KTextEditor::Cursor KateLayoutCache::viewCacheEnd( ) const
{
  return m_textLayouts.count() ? m_textLayouts.last().end() : KTextEditor::Cursor();
}

int KateLayoutCache::viewWidth( ) const
{
  return m_viewWidth;
}

/**
 * This returns the view line upon which realCursor is situated.
 * The view line is the number of lines in the view from the first line
 * The supplied cursor should be in real lines.
 */
int KateLayoutCache::viewLine(const KTextEditor::Cursor& realCursor)
{
  if (realCursor.column() <= 0 || realCursor.line() < 0) return 0;

  Q_ASSERT(realCursor.line() < m_renderer->doc()->lines());
  KateLineLayoutPtr thisLine = line(realCursor.line());

  for (int i = 0; i < thisLine->viewLineCount(); ++i) {
    const KateTextLayout& l = thisLine->viewLine(i);
    if (realCursor.column() >= l.startCol() && realCursor.column() < l.endCol())
      return i;
  }

  return thisLine->viewLineCount() - 1;
}

int KateLayoutCache::displayViewLine(const KTextEditor::Cursor& virtualCursor, bool limitToVisible)
{
  if (!virtualCursor.isValid())
    return -1;

  KTextEditor::Cursor work = viewCacheStart();
  
  // only try this with valid lines!
  if (work.isValid())
    work.setLine(m_renderer->folding().lineToVisibleLine(work.line()));

  if (!work.isValid())
    return virtualCursor.line();

  int limit = m_textLayouts.count();

  // Efficient non-word-wrapped path
  if (!m_renderer->view()->dynWordWrap()) {
    int ret = virtualCursor.line() - work.line();
    if (limitToVisible && (ret < 0 || ret > limit))
      return -1;
    else
      return ret;
  }

  if (work == virtualCursor) {
    return 0;
  }

  int ret = -(int)viewLine(viewCacheStart());
  bool forwards = (work < virtualCursor);

  // FIXME switch to using ranges? faster?
  if (forwards) {
    while (work.line() != virtualCursor.line()) {
      ret += viewLineCount(m_renderer->folding().visibleLineToLine(work.line()));
      work.setLine(work.line() + 1);
      if (limitToVisible && ret > limit)
        return -1;
    }
  } else {
    while (work.line() != virtualCursor.line()) {
      work.setLine(work.line() - 1);
      ret -= viewLineCount(m_renderer->folding().visibleLineToLine(work.line()));
      if (limitToVisible && ret < 0)
        return -1;
    }
  }

  // final difference
  KTextEditor::Cursor realCursor = virtualCursor;
  realCursor.setLine(m_renderer->folding().visibleLineToLine(realCursor.line()));
  if (realCursor.column() == -1) realCursor.setColumn(m_renderer->doc()->lineLength(realCursor.line()));
  ret += viewLine(realCursor);

  if (limitToVisible && (ret < 0 || ret > limit))
    return -1;

  return ret;
}

int KateLayoutCache::lastViewLine(int realLine)
{
  if (!m_renderer->view()->dynWordWrap()) return 0;

  KateLineLayoutPtr l = line(realLine);
  Q_ASSERT(l);
  return l->viewLineCount() - 1;
}

int KateLayoutCache::viewLineCount(int realLine)
{
  return lastViewLine(realLine) + 1;
}

void KateLayoutCache::viewCacheDebugOutput( ) const
{
  kDebug( 13033 ) << "Printing values for " << m_textLayouts.count() << " lines:";
  if (m_textLayouts.count())
  {
  foreach (const KateTextLayout& t, m_textLayouts)
    if (t.isValid())
    {
      t.debugOutput();
    }
    else
    {
      kDebug( 13033 ) << "Line Invalid.";
    }
  }
}

void KateLayoutCache::wrapLine (const KTextEditor::Cursor &position)
{
   m_lineLayouts.slotEditDone (position.line(), position.line() + 1, 1);
}

void KateLayoutCache::unwrapLine (int line)
{
   m_lineLayouts.slotEditDone (line - 1, line, -1);
}

void KateLayoutCache::insertText (const KTextEditor::Cursor &position, const QString &)
{
   m_lineLayouts.slotEditDone(position.line(), position.line(), 0);
}

void KateLayoutCache::removeText (const KTextEditor::Range &range)
{
   m_lineLayouts.slotEditDone(range.start().line(), range.start().line(), 0);
}

void KateLayoutCache::clear( )
{
  m_textLayouts.clear();
  m_lineLayouts.clear();
  m_startPos = KTextEditor::Cursor(-1,-1);
}

void KateLayoutCache::setViewWidth( int width )
{
  bool wider = width > m_viewWidth;

  m_viewWidth = width;

  m_lineLayouts.clear();
  m_startPos = KTextEditor::Cursor(-1,-1);

  // Only get rid of layouts that we have to
  if (wider) {
    m_lineLayouts.viewWidthIncreased();
  } else {
    m_lineLayouts.viewWidthDecreased(width);
  }
}

bool KateLayoutCache::wrap( ) const
{
  return m_wrap;
}

void KateLayoutCache::setWrap( bool wrap )
{
  m_wrap = wrap;
  clear();
}

void KateLayoutCache::relayoutLines( int startRealLine, int endRealLine )
{
  if (startRealLine > endRealLine)
    kWarning() << "start" << startRealLine << "before end" << endRealLine;

  m_lineLayouts.relayoutLines(startRealLine, endRealLine);
}

bool KateLayoutCache::acceptDirtyLayouts()
{
  return m_acceptDirtyLayouts;
}

void KateLayoutCache::setAcceptDirtyLayouts(bool accept)
{
  m_acceptDirtyLayouts = accept;
}

// kate: space-indent on; indent-width 2; replace-tabs on;