/*************************************************************************************
 *  Copyright (C) 2008 by Aleix Pol <aleixpol@kde.org>                               *
 *                                                                                   *
 *  This program is free software; you can redistribute it and/or                    *
 *  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   *
 *************************************************************************************/

#include "kalgebraplasma.h"

#include <QPainter>
#include <QFontMetrics>
#include <QSizeF>
#include <QLabel>
#include <QGraphicsProxyWidget>
#include <QFont>

#include <plasma/theme.h>
#include <plasma/dataengine.h>

#include "expression.h"

using namespace Plasma;
using Analitza::Expression;

QColor KAlgebraPlasmoid::correctColor() { return Theme::defaultTheme()->color(Theme::TextColor);}
QColor KAlgebraPlasmoid::errorColor() { return Qt::red; }
int KAlgebraPlasmoid::simplificationSize() {  return Theme::defaultTheme()->font(Theme::DefaultFont).pointSize(); }
int KAlgebraPlasmoid::resultSize() { return simplificationSize()*2; }

KAlgebraPlasmoid::KAlgebraPlasmoid(QObject *parent, const QVariantList &args)
	: Applet(parent, args), m_layout(0)
{
	KGlobal::locale()->insertCatalog("kalgebra");
	setBackgroundHints(TranslucentBackground);
	
	setAspectRatioMode(IgnoreAspectRatio);
}

KAlgebraPlasmoid::~KAlgebraPlasmoid() {}

void KAlgebraPlasmoid::init()
{
	m_input = new Plasma::LineEdit(this);
	m_input->setClearButtonShown(true);
	m_input->setFocus();
	
	m_output = new Plasma::Label(this);
	m_output->setMinimumSize(20, 20);
	m_output->nativeWidget()->setAlignment(Qt::AlignCenter);
	
	m_layout = new QGraphicsLinearLayout(this);
	m_layout->addItem(m_input);
	m_layout->addItem(m_output);
	
	connect(m_input, SIGNAL(editingFinished()), this, SLOT(addOperation()));
	connect(m_input->nativeWidget(), SIGNAL(textChanged(QString)), this, SLOT(simplify()));
	
	updateFactor();
	resize(300,300);
}

void KAlgebraPlasmoid::updateFactor()
{
	switch(formFactor()) {
		case Horizontal:
			m_input->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::MinimumExpanding);
			m_layout->setOrientation(Qt::Horizontal);
			break;
		default:
			m_input->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Fixed);
			m_layout->setOrientation(Qt::Vertical);
			break;
	}
}

void KAlgebraPlasmoid::constraintsEvent(Constraints constraints)
{
	Q_ASSERT(m_layout);
	if(constraints & FormFactorConstraint) {
		updateFactor();
	}
}

void KAlgebraPlasmoid::addOperation()
{
	if ( m_input->text().isEmpty() )
		return;
	
	Expression res;
	a.setExpression(Expression(m_input->text(), false));
	if(a.isCorrect()) {
		res=a.evaluate();
	}
	
	QColor c;
	if(a.isCorrect()) {
		m_output->setText(res.toString());
		c=correctColor();
	} else {
		m_output->setText(a.errors().join("\n"));
		c=errorColor();
	}
	plasmoidFont(true, c, true);
	update();
}

void KAlgebraPlasmoid::plasmoidFont(bool big, const QColor& c, bool bold)
{
	QFont f=m_output->nativeWidget()->font();
	f.setBold(bold);
	int size;
	
	if(formFactor()==Horizontal) {
		f.setPointSize(Theme::defaultTheme()->font(Theme::DefaultFont).pointSize());
		QFontMetrics fm(f);
		m_output->setMinimumWidth(fm.width(m_output->text()));
	} else {
		if(big) {
			size=(m_output->size().height()*2)/3;
			f.setPointSize(size);
			QFontMetrics fm(f);
			
			int w=m_output->nativeWidget()->width();
			Q_ASSERT(w>0);
			for(; fm.width(m_output->text()) > w; size--) {
				f.setPointSize(size);
				fm=QFontMetrics(f);
			}
		} else
			size=simplificationSize();
		f.setPointSize(size);
	}
	
	QPalette palette = m_output->palette();
	palette.setColor(QPalette::WindowText, c);
	m_output->nativeWidget()->setPalette(palette);
	m_output->nativeWidget()->setFont(f);
}

void KAlgebraPlasmoid::simplify()
{
	Expression e(m_input->text(), false);
	if(e.isCorrect())
		a.setExpression(e);
	
	if(e.isCorrect() && a.isCorrect()) {
		a.simplify();
		m_output->setText(a.expression().toString());
		
		plasmoidFont(false, correctColor(), true);
	} else
		m_output->setText(QString());
}

#include "kalgebraplasma.moc"