/***************************************************************************
 *   Copyright (c) 2015 Eivind Kvedalen <eivind@kvedalen.name>             *
 *                                                                         *
 *   This file is part of the FreeCAD CAx development system.              *
 *                                                                         *
 *   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., 59 Temple Place,         *
 *   Suite 330, Boston, MA  02111-1307, USA                                *
 *                                                                         *
 ***************************************************************************/

#ifndef EXPRESSIONCOMPLETER_H
#define EXPRESSIONCOMPLETER_H

#include <QCompleter>
#include <QLineEdit>
#include <QObject>
#include <QPlainTextEdit>
#include <QValidator>
#include <App/DocumentObserver.h>
#include <App/ExpressionTokenizer.h>

class QStandardItem;

namespace App
{
class Document;
class DocumentObject;
class Property;
class ObjectIdentifier;
}  // namespace App

namespace Gui
{

enum class ActivationMode
{
    Highlighted,  // browsing with arrow keys
    Activated     // confirmed selection (Enter/Click)
};

class GuiExport ExpressionValidator: public QValidator
{
    Q_OBJECT

public:
    explicit ExpressionValidator(QObject* parent = nullptr);
    void fixup(QString& input) const override;
    QValidator::State validate(QString& input, int& pos) const override;
};

/**
 * @brief The ExpressionCompleter class extends the QCompleter class to provide a completer model of
 * documentobject names and properties.
 */

class GuiExport ExpressionCompleter: public QCompleter
{
    Q_OBJECT
public:
    ExpressionCompleter(
        const App::DocumentObject* currentDocObj,
        QObject* parent = nullptr,
        bool noProperty = false,
        bool checkInList = true
    );

    void getPrefixRange(int& start, int& end) const
    {
        tokenizer.getPrefixRange(start, end);
    }

    void updatePrefixEnd(int end)
    {
        tokenizer.updatePrefixEnd(end);
    }

    void setDocumentObject(const App::DocumentObject*, bool checkInList = true);

    void setNoProperty(bool enabled = true);

public Q_SLOTS:
    void slotUpdate(const QString& prefix, int pos);

Q_SIGNALS:
    void completerSlotUpdated();

private:
    void init();
    QString pathFromIndex(const QModelIndex& index) const override;
    QStringList splitPath(const QString& input) const override;

    App::DocumentObjectT currentObj;
    App::ExpressionTokenizer tokenizer;
    bool noProperty;
    bool checkInList;
};

class GuiExport ExpressionLineEdit: public QLineEdit
{
    Q_OBJECT
    Q_PROPERTY(ExpressionCompleter* completer READ getCompleter)
public:
    ExpressionLineEdit(
        QWidget* parent = nullptr,
        bool noProperty = false,
        char checkPrefix = 0,
        bool checkInList = true
    );
    void setDocumentObject(const App::DocumentObject* currentDocObj, bool checkInList = true);
    void setPrefix(char prefix);
    bool completerActive() const;
    void hideCompleter();
    void setNoProperty(bool enabled = true);
    void setExactMatch(bool enabled = true);
    ExpressionCompleter* getCompleter(void);
Q_SIGNALS:
    void textChanged2(QString text, int pos);
public Q_SLOTS:
    void slotTextChanged(const QString& text);
    void slotCompleteText(const QString& completionPrefix, ActivationMode mode);
    void slotCompleteTextHighlighted(const QString& completionPrefix);
    void slotCompleteTextSelected(const QString& completionPrefix);

protected:
    void keyPressEvent(QKeyEvent* event) override;
    void contextMenuEvent(QContextMenuEvent* event) override;

private:
    ExpressionCompleter* completer;
    bool block;
    bool noProperty;
    bool exactMatch;
    bool checkInList;
    char checkPrefix;
};

class GuiExport ExpressionTextEdit: public QPlainTextEdit
{
    Q_OBJECT
public:
    ExpressionTextEdit(QWidget* parent = nullptr);
    void setDocumentObject(const App::DocumentObject* currentDocObj);
    bool completerActive() const;
    void hideCompleter();
    void setExactMatch(bool enabled = true);
    QSize sizeHint() const override;

protected:
    void keyPressEvent(QKeyEvent* event) override;
    void contextMenuEvent(QContextMenuEvent* event) override;
Q_SIGNALS:
    void textChanged2(QString text, int pos);
public Q_SLOTS:
    void slotTextChanged();
    void slotCompleteText(const QString& completionPrefix, ActivationMode mode);
    void slotCompleteTextHighlighted(const QString& completionPrefix);
    void slotCompleteTextSelected(const QString& completionPrefix);
    void adjustCompleterToCursor();

private:
    ExpressionCompleter* completer;
    bool block;
    bool exactMatch;
};

class GuiExport ExpressionParameter
{
public:
    static ExpressionParameter* instance();
    bool isCaseSensitive() const;
    bool isExactMatch() const;
};

}  // namespace Gui

#endif  // EXPRESSIONCOMPLETER_H