#include "tundo.h"

#include <deque></deque>

//-----------------------------------------------------------------------------

using std::for_each;

namespace {

void deleteUndo(const TUndo *undo) { delete undo; }

void callUndo(const TUndo *undo) { undo->undo(); }

void callRedo(const TUndo *undo) { undo->redo(); }

// void callRepeat(const TUndo* undo) {undo->repeat(); }

class TUndoBlock final : public TUndo {

  std::vector<tundo *=""> m_undos;</tundo>

  typedef std::vector<tundo *="">::const_iterator Iterator;</tundo>

  typedef std::vector<tundo *="">::const_reverse_iterator ReverseIterator;</tundo>

  mutable bool m_deleted, m_undoing;

public:

  TUndoBlock() : m_deleted(false), m_undoing(false) {}

  ~TUndoBlock() {

    assert(m_undoing == false);

    assert(m_deleted == false);

    m_deleted = true;

    for_each(m_undos.begin(), m_undos.end(), deleteUndo);

    m_undos.clear();

  }

  int getSize() const override {

    int size = sizeof(*this);

    for (Iterator cit = m_undos.begin(); cit != m_undos.end(); ++cit)

      size += (*cit)->getSize();

    size += (m_undos.capacity() - m_undos.size()) * sizeof(TUndo *);

    return size;

  }

  int getUndoCount() const { return (int)m_undos.size(); }

  void setLast() {

    for (UINT i                   = 1; i < m_undos.size(); i++)

      m_undos[i]->m_isLastInBlock = false;

    m_undos[0]->m_isLastInBlock   = true;

  }

  void undo() const override {

    assert(!m_deleted);

    assert(!m_undoing);

    m_undoing = true;

    // VERSIONE CORRETTA

    for_each(m_undos.rbegin(), m_undos.rend(), callUndo);

    // VERSIONE SBAGLIATA

    // for_each(m_undos.begin(), m_undos.end(), callUndo);

    m_undoing = false;

  }

  void redo() const override {

    assert(!m_deleted);

    // VERSIONE CORRETTA

    for_each(m_undos.begin(), m_undos.end(), callRedo);

    // VERSIONE SBAGLIATA

    // for_each(m_undos.rbegin(), m_undos.rend(), callRedo);

  }

  // void repeat() const {

  //  for_each(m_undos.begin(), m_undos.end(), callRepeat);

  //}

  void onAdd() override {}

  void add(TUndo *undo) {

    undo->m_isLastInBlock = true;

    m_undos.push_back(undo);

  }

  void popUndo(int n) {

    if (n == -1) n = m_undos.size();

    if (m_undos.empty() || n <= 0) return;

    while (n > 0 && !m_undos.empty()) {

      TUndo *undo = m_undos.back();

      m_undos.pop_back();

      delete undo;

      n--;

    }

  }

  QString getHistoryString() override {

    if (m_undos.empty())

      return TUndo::getHistoryString();

    else if ((int)m_undos.size() == 1)

      return m_undos.back()->getHistoryString();

    else {

      return QString("%1  etc..").arg(m_undos.back()->getHistoryString());

    }

  }

  int getHistoryType() override {

    if (m_undos.empty())

      return TUndo::getHistoryType();

    else

      return m_undos.back()->getHistoryType();

  }

};

}

typedef std::deque<tundo *=""> UndoList;</tundo>

typedef UndoList::iterator UndoListIterator;

typedef UndoList::const_iterator UndoListConstIterator;

//-----------------------------------------------------------------------------

struct TUndoManager::TUndoManagerImp {

  UndoList m_undoList;

  UndoListIterator m_current;

  bool m_skipped;

  int m_undoMemorySize;  // in bytes

  std::vector<tundoblock *=""> m_blockStack;</tundoblock>

public:

  TUndoManagerImp() : m_skipped(false), m_undoMemorySize(0) {

    m_current = m_undoList.end();

  }

  ~TUndoManagerImp() {}

  void add(TUndo *undo);

public:

  static struct ManagerPtr {

    TUndoManager *m_ptr;

  public:

    ManagerPtr() : m_ptr(0) {}

    ~ManagerPtr() {

      if (m_ptr) delete m_ptr;

      m_ptr = 0;

    }

  } theManager;

private:

  void doAdd(TUndo *undo);

};

//=============================================================================

TUndoManager::TUndoManagerImp::ManagerPtr

    TUndoManager::TUndoManagerImp::theManager;

//-----------------------------------------------------------------------------

TUndoManager *TUndoManager::manager() {

  if (!TUndoManagerImp::theManager.m_ptr)

    TUndoManagerImp::theManager.m_ptr = new TUndoManager;

  return TUndoManagerImp::theManager.m_ptr;

}

//=============================================================================

TUndoManager::TUndoManager() : m_imp(new TUndoManagerImp) {}

//-----------------------------------------------------------------------------

TUndoManager::~TUndoManager() {

  // cout << "Distrutto undo manager" << endl;

  assert(m_imp->m_blockStack.empty());

  reset();

}

//-----------------------------------------------------------------------------

void TUndoManager::TUndoManagerImp::add(TUndo *undo) {

  assert(undo);

  if (!m_blockStack.empty()) {

    assert(m_current == m_undoList.end());

    m_blockStack.back()->add(undo);

  } else

    doAdd(undo);

}

//-----------------------------------------------------------------------------

void TUndoManager::TUndoManagerImp::doAdd(TUndo *undo) {

  if (m_current != m_undoList.end()) {

    for_each(m_current, m_undoList.end(), deleteUndo);

    m_undoList.erase(m_current, m_undoList.end());

  }

  int i, memorySize = 0, count = m_undoList.size();

  for (i = 0; i < count; i++) memorySize += m_undoList[i]->getSize();

  while (

      count > 100 ||

      (count != 0 && memorySize + undo->getSize() > m_undoMemorySize))  // 20MB

  {

    --count;

    TUndo *undo = m_undoList.front();

    m_undoList.pop_front();

    memorySize -= undo->getSize();

    delete undo;

  }

  undo->m_isLastInBlock = true;

  m_undoList.push_back(undo);

  m_current = m_undoList.end();

}

//-----------------------------------------------------------------------------

void TUndoManager::beginBlock() {

  if (m_imp->m_current != m_imp->m_undoList.end()) {

    for_each(m_imp->m_current, m_imp->m_undoList.end(), deleteUndo);

    m_imp->m_undoList.erase(m_imp->m_current, m_imp->m_undoList.end());

  }

  TUndoBlock *undoBlock = new TUndoBlock;

  m_imp->m_blockStack.push_back(undoBlock);

  m_imp->m_current = m_imp->m_undoList.end();

}

//-----------------------------------------------------------------------------

void TUndoManager::endBlock() {

  // vogliamo fare anche resize del vector ???

  assert(m_imp->m_blockStack.empty() == false);

  TUndoBlock *undoBlock = m_imp->m_blockStack.back();

  m_imp->m_blockStack.pop_back();

  if (undoBlock->getUndoCount() > 0) {

    undoBlock->setLast();

    m_imp->add(undoBlock);

    emit historyChanged();

  } else {

    delete undoBlock;

    m_imp->m_current = m_imp->m_undoList.end();

  }

}

//-----------------------------------------------------------------------------

bool TUndoManager::undo() {

  assert(m_imp->m_blockStack.empty());

  UndoListIterator &it = m_imp->m_current;

  if (it != m_imp->m_undoList.begin()) {

    m_imp->m_skipped = false;

    --it;

    (*it)->undo();

    emit historyChanged();

    if (m_imp->m_skipped) {

      m_imp->m_skipped = false;

      return undo();

    }

    return true;

  } else

    return false;

}

//-----------------------------------------------------------------------------

bool TUndoManager::redo() {

  assert(m_imp->m_blockStack.empty());

  UndoListIterator &it = m_imp->m_current;

  if (it != m_imp->m_undoList.end()) {

    m_imp->m_skipped = false;

    (*it)->redo();

    ++it;

    emit historyChanged();

    if (m_imp->m_skipped) {

      m_imp->m_skipped = false;

      return redo();

    }

    return true;

  } else

    return false;

}

//-----------------------------------------------------------------------------

// repeat e' come redo ma non sposta il puntatore al corrente

/*

void TUndoManager::repeat()

{

  assert(m_imp->m_blockStack.empty());

  UndoListIterator &it = m_imp->m_current;

  if (it != m_imp->m_undoList.end())

  {

    (*it)->repeat();

  }

}

*/

//-----------------------------------------------------------------------------

void TUndoManager::skip() { m_imp->m_skipped = true; }

//-----------------------------------------------------------------------------

void TUndoManager::setUndoMemorySize(int memorySyze) {

  m_imp->m_undoMemorySize = 1048576 * memorySyze;

}

//-----------------------------------------------------------------------------

void TUndoManager::add(TUndo *undo) {

  assert(undo);

  if (!undo) return;

  m_imp->add(undo);

  Q_EMIT historyChanged();

  undo->onAdd();

  Q_EMIT somethingChanged();

}

//-----------------------------------------------------------------------------

void TUndoManager::reset() {

  assert(m_imp->m_blockStack.empty());

  m_imp->m_blockStack.clear();

  UndoList &lst = m_imp->m_undoList;

  for_each(lst.begin(), lst.end(), deleteUndo);

  lst.clear();

  m_imp->m_current = m_imp->m_undoList.end();

  Q_EMIT historyChanged();

}

//-----------------------------------------------------------------------------

void TUndoManager::popUndo(int n, bool forward) {

  if (!forward) {

    if (m_imp->m_blockStack.empty()) {

      if (n == -1) {

        UndoListIterator start = m_imp->m_undoList.begin();

        n                      = 0;

        while (start != m_imp->m_current) ++n;

      }

      if (m_imp->m_undoList.empty() || n <= 0) return;

      if (m_imp->m_current == m_imp->m_undoList.end()) {

        int i;

        for (i = 0; i < n && m_imp->m_current != m_imp->m_undoList.begin();

             i++) {

          m_imp->m_current--;

          delete (*m_imp->m_current);

          m_imp->m_undoList.erase(m_imp->m_current);

          m_imp->m_current = m_imp->m_undoList.end();

        }

      } else {

        TUndo *undo = *m_imp->m_current;

        UndoListIterator start, end = m_imp->m_current;

        if (end == m_imp->m_undoList.begin()) return;

        int i;

        for (i = 0; i < n && m_imp->m_current != m_imp->m_undoList.begin(); i++)

          m_imp->m_current--;

        start                 = m_imp->m_current;

        UndoListIterator _end = end;

        while (_end != start) {

          _end--;

          delete (*_end);

        }

        m_imp->m_undoList.erase(start, end);

        m_imp->m_current = m_imp->m_undoList.begin();

        while (*m_imp->m_current != undo) m_imp->m_current++;

      }

    } else

      m_imp->m_blockStack.back()->popUndo(n);

    return;

  }

  if (m_imp->m_current == m_imp->m_undoList.end()) return;

  if (m_imp->m_blockStack.empty()) {

    UndoListIterator end, start = m_imp->m_current++;

    if (n == -1)

      end = m_imp->m_undoList.end();

    else {

      UndoListIterator it = start;

      end                 = it;

      int i               = 0;

      while (i != n && end != m_imp->m_undoList.end()) {

        ++end;

        i++;

      }

    }

    for_each(start, end, deleteUndo);

    m_imp->m_undoList.erase(start, end);

    m_imp->m_current = m_imp->m_undoList.end();

  } else

    m_imp->m_blockStack.back()->popUndo(n);

}

//-----------------------------------------------------------------------------

int TUndoManager::getHistoryCount() { return (int)m_imp->m_undoList.size(); }

//-----------------------------------------------------------------------------

int TUndoManager::getCurrentHistoryIndex() {

  int index           = 0;

  UndoListIterator it = m_imp->m_undoList.begin();

  while (1) {

    if (it == m_imp->m_current) return index;

    if (it == m_imp->m_undoList.end()) break;

    index++;

    it++;

  }

  return 0;

}

//-----------------------------------------------------------------------------

TUndo *TUndoManager::getUndoItem(int index) {

  if (index > (int)m_imp->m_undoList.size() || index <= 0) return 0;

  return m_imp->m_undoList.at(index - 1);

}