/*************************************************************************************
 *                                                                                   *
 *  This program is free software; you can redistribute it and/or                    *
 *  Copyright (C) 2007 by Aleix Pol <aleixpol@kde.org>                               *
 *  modify it under the terms of the GNU 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   *
 *************************************************************************************/

#ifndef EXPRESSIONEDIT_H
#define EXPRESSIONEDIT_H

#include <QPlainTextEdit>
#include <QCompleter>
#include <QLabel>
#include <QTreeView>
#include <analitzagui/algebrahighlighter.h>

#include "analitzawidgets_export.h"

class QKeyEvent;

class OperatorsModel;

namespace Analitza
{
class Variables;
class Analyzer;
class Expression;

/**
 * \class ExpressionEdit
 * 
 * \ingroup AnalitzaGUIModule
 *
 * \brief A widget for manipulate mathemathical expressions.
 *
 * The expression edit widget is the one where we will input our expressions.
 */

class ANALITZAWIDGETS_EXPORT ExpressionEdit : public QPlainTextEdit
{
    Q_OBJECT
    public:
        /** Constructor. Creates a new ExpressionEdit.
        *    @param parent is the widget parent.
        *    @param ini specifies what input format is going to expect the highlighting.
        */
        explicit ExpressionEdit(QWidget *parent = nullptr, AlgebraHighlighter::Mode ini=AlgebraHighlighter::Autodetect);
        
        /** Destructor. */
        ~ExpressionEdit() override;
        
        /** Returns the ExpressionEdit input mode. */
        AlgebraHighlighter::Mode mode() { return m_highlight->mode(); }
        
        /** Sets the ExpressionEdit input mode. */
        void setMode(AlgebraHighlighter::Mode en);
        
        /** Returns whether there is MathML on the widget. */
        bool isMathML() const;
        
        /** Sets an Analyzer @p in module associated to the ExpressionEdit. It is used to autocomplete variables. */
        void setAnalitza(Analitza::Analyzer* in);
        
        /** Returns the expression string that we have. */
        QString text() const { return this->toPlainText();}
        
        /** Sets the expression string @p str we have. */
        void setText(const QString &str) { setPlainText(str);}
        
        /** Sets whether it is correct. Changes the background color. */
        void setCorrect(bool cor);
        
        /** Checks whether it has been set to correct. */
        bool isCorrect() const;
        
        /** Sets the string @p ans that will be entered when an operator is pressed. */
        void setAns(const QString &ans) { m_ans=ans; }
        
        /** Returns the string that will be entered when the first operator is pressed. */
        QString ans() const { return m_ans; }
        
        /** Sets an expression to the input box. */
        void setExpression(const Analitza::Expression& e);
        
        /** Returns the expression we have in the text. */
        Analitza::Expression expression() const;
        
        /** Sets the @p examples to be shown in the context menu */
        void setExamples(const QStringList& ex) { m_examples=ex; }
    public Q_SLOTS:
        
        /** Inserts @p text text where the cursor is and selects it */
        void insertText(const QString& text);
        
    private Q_SLOTS:
        void showSimplified();
        void cursorMov();
        void updateCompleter();
        void setActionText(QAction* text);
        
        /** Shows a little tip widget containing the string @p str. If @p str is empty the widget is hidden. */
        void helper(const QString& str);
        
        /** Tries to complete the currently edited word with the @p word. */
        void completed(const QString &word);
        
        /** Sets the Mode to MathML */
        void toMathML() { setMode(AlgebraHighlighter::MathML); }
        
        /** Sets the Mode to Expression */
        void toExpression() { setMode(AlgebraHighlighter::Expression); }
        
        /** Simplify the current expression. */
        void simplify();
        
        /** Is the execution function, when return is pressed. */
        void returnP(); //FIXME: Change my name please
        
    Q_SIGNALS:
        /** Emits that a return has been pressed. */
        void returnPressed();
        
        /** Deprecated. */
        void signalHelper(QString);
        
    protected:
        /** Inherited from QTextEdit, just deals with the menu. */
        void contextMenuEvent(QContextMenuEvent * e) override;
    
    private:
        bool returnPress();
        QString helpShow(const QString& funcname, int param, bool bounds, const Analitza::Variables* v) const;
        void helper(const QString&, const QPoint& p);
        QString lastWord(int);
        void focusInEvent (QFocusEvent * event) override;
        void focusOutEvent ( QFocusEvent * event ) override;
        
        void removenl();
        void keyPressEvent(QKeyEvent * e) override;
        
        QLabel *m_helptip;
        AlgebraHighlighter *m_highlight;
        
        int m_histPos;
        QStringList m_history;
        
        Analitza::Analyzer *a;
        bool m_correct;
        QString m_ans;
        QCompleter *m_completer;
        OperatorsModel *m_ops;
        
        QStringList m_examples;
        QTimer* m_hideHelpTip;
        int m_lineHeight;
};

}

#endif
