/*
  Copyright (C) 2010-2012 Sérgio Martins <iamsergio@gmail.com>

  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.
*/

#ifndef AKONADI_HISTORY_P_H
#define AKONADI_HISTORY_P_H

#include "history.h"
#include "incidencechanger.h"
#include <kcalcore/incidence.h>
#include <akonadi/collection.h>

#include <QPointer>
#include <QStack>
#include <QVector>

using namespace Akonadi;
using namespace KCalCore;

namespace Akonadi {

class History;

enum OperationType {
    TypeNone,
    TypeUndo,
    TypeRedo
};

class Entry : public QObject {
    Q_OBJECT
public:
    typedef QSharedPointer<Entry> Ptr;
    typedef QVector<Entry::Ptr> List;
    Entry(const Akonadi::Item &item, const QString &description, History *qq);
    Entry(const Akonadi::Item::List &items, const QString &description, History *qq);
    virtual void updateIds(Item::Id oldId, Item::Id newId);
    void doIt(OperationType);

    Akonadi::Item::List mItems;
    QString mDescription;
Q_SIGNALS:
    void finished(Akonadi::IncidenceChanger::ResultCode, const QString &errorString);
protected:
    virtual bool undo() = 0;
    virtual bool redo() = 0;
    void updateIdsGlobaly(Item::Id oldId, Item::Id newId);
    QWidget* currentParent() const;
    IncidenceChanger *mChanger;
    QHash<Akonadi::Item::Id,int> mLatestRevisionByItemId;
    History *q;
    QVector<int> mChangeIds;
private:
    void init(const QString &description, History *qq);
    Q_DISABLE_COPY(Entry)
};

class History::Private : public QObject {
    Q_OBJECT
public:
    Private(History *qq);
    ~Private() {}
    void doIt(OperationType);
    void stackEntry(const Entry::Ptr &entry, uint atomicOperationId);
    void updateIds(Item::Id oldId, Item::Id newId);
    void finishOperation(int changeId, History::ResultCode, const QString &errorString);
    QStack<Entry::Ptr>& destinationStack();
    QStack<Entry::Ptr>& stack(OperationType);
    QStack<Entry::Ptr>& stack();
    void undoOrRedo(OperationType, QWidget *parent);

    void emitDone(OperationType, History::ResultCode);
    void setEnabled(bool enabled);

    bool isUndoAvailable() const;
    bool isRedoAvailable() const;

    int redoCount() const;
    int undoCount() const;

    IncidenceChanger *mChanger;

    QStack<Entry::Ptr> mUndoStack;
    QStack<Entry::Ptr> mRedoStack;

    OperationType mOperationTypeInProgress;

    Entry::Ptr mEntryInProgress;

    QString mLastErrorString;
    bool mUndoAllInProgress;

    /**
      * When recordCreation/Deletion/Modification is called and an undo operation is already in progress
      * the entry is added here.
      */
    QVector<Entry::Ptr> mQueuedEntries;
    bool mEnabled;
    QPointer<QWidget> mCurrentParent;

public Q_SLOTS:
    void handleFinished(Akonadi::IncidenceChanger::ResultCode, const QString &errorString);

private:
    History *q;
};

class CreationEntry : public Entry {
    Q_OBJECT
public:
    typedef QSharedPointer<CreationEntry> Ptr;
    CreationEntry(const Akonadi::Item &item, const QString &description, History *q);

    /**reimp*/
    bool undo();

    /** reimp */
    bool redo();

private Q_SLOTS:
    void onDeleteFinished(int changeId, const QVector<Akonadi::Item::Id> &deletedIds,
                          Akonadi::IncidenceChanger::ResultCode resultCode,
                          const QString &errorString);

    void onCreateFinished(int changeId, const Akonadi::Item &item,
                          Akonadi::IncidenceChanger::ResultCode resultCode,
                          const QString &errorString);
private:
    Q_DISABLE_COPY(CreationEntry)
};

class DeletionEntry : public Entry {
    Q_OBJECT
public:
    DeletionEntry(const Akonadi::Item::List &items, const QString &description, History *q);
    /**reimp*/ bool undo();
    /**reimp*/ bool redo();

private Q_SLOTS:
    void onDeleteFinished(int changeId, const QVector<Akonadi::Item::Id> &deletedIds,
                          Akonadi::IncidenceChanger::ResultCode resultCode,
                          const QString &errorString);

    void onCreateFinished(int changeId, const Akonadi::Item &item,
                          Akonadi::IncidenceChanger::ResultCode resultCode,
                          const QString &errorString);
private:
    IncidenceChanger::ResultCode mResultCode;
    QString mErrorString;
    QHash<int,Akonadi::Item::Id> mOldIdByChangeId;
    int mNumPendingCreations;
    Q_DISABLE_COPY(DeletionEntry)
};

class ModificationEntry : public Entry {
    Q_OBJECT
public:
    ModificationEntry(const Akonadi::Item &item,
                      const Incidence::Ptr &originalPayload,
                      const QString &description,
                      History *q);

    /**reimp*/ bool undo();
    /**reimp*/ bool redo();

private Q_SLOTS:
    void onModifyFinished(int changeId, const Akonadi::Item &item,
                          Akonadi::IncidenceChanger::ResultCode resultCode,
                          const QString &errorString);
private:
    Q_DISABLE_COPY(ModificationEntry)
    Incidence::Ptr mOriginalPayload;
};

class MultiEntry : public Entry {
    Q_OBJECT
public:
    typedef QSharedPointer<MultiEntry> Ptr;
    MultiEntry(int id, const QString &description, History *q);

    void addEntry(const Entry::Ptr &entry);
    /** reimp */ void updateIds(Item::Id oldId, Item::Id newId);

protected:
    /**reimp*/
    bool undo();
    /**reimp*/ bool redo();

private Q_SLOTS:
    void onEntryFinished(Akonadi::IncidenceChanger::ResultCode resultCode,
                         const QString &errorString);
public:
    const uint mAtomicOperationId;
private:
    Entry::List mEntries;
    int mFinishedEntries;
    OperationType mOperationInProgress;
    Q_DISABLE_COPY(MultiEntry)
};

}

#endif