// Janek Kozicki 2007 - a small example of using units with QT4 GUI

#include <QtUiTools>
#include <QtGui>

#include "calculatorform.h"
#include <iostream>

using namespace boost::units;

CalculatorForm::CalculatorForm(QWidget *parent)
    : QWidget(parent)
{
    QUiLoader loader;

    QFile file(":/forms/calculatorform.ui");
    file.open(QFile::ReadOnly);
    QWidget *formWidget = loader.load(&file, this);
    file.close();

    acc_input  = qFindChild<QDoubleSpinBox*>(this, "acc_input");
    mass_input = qFindChild<QDoubleSpinBox*>(this, "mass_input");
    acc_unit_box = qFindChild<QComboBox*>(this, "acc_combo");
    mass_unit_box = qFindChild<QComboBox*>(this, "mass_combo");
    force_txt = qFindChild<QLabel*>(this, "force_txt");
    force_unit_box = qFindChild<QComboBox*>(this, "force_combo");

//////////////////////////////////////////////////////
//////////////////////////////////////////////////////
// adding conversion values by hand. But see note [1] on the bottom of this file
//
    force_unit_box->addItem("N"   , 1.0);
    force_unit_box->addItem("kN"  , 1000.0);
    force_unit_box->addItem("dyne", 0.0001 );
// why this is not working?
//    force_unit_box->addItem("dyne", (1.0*CGS::dyne/SI::newton).value() );
// or this?
//    force_unit_box->addItem("dyne", static_cast<double>(1.0*CGS::dyne/SI::newton) );

    mass_unit_box->addItem("kg"   , 1.0);
    mass_unit_box->addItem("g"    , 0.001);

    acc_unit_box->addItem("m/s^2" , 1.0);
    acc_unit_box->addItem("km/s^2", 1000);
    acc_unit_box->addItem("gal"   , 0.01 );
// or without a cast? - most preferable solution (dimensionless should implicitly convert to double)
//    acc_unit_box->addItem("gal"   , (1.0*CGS::gal/(SI::meter/(SI::second*SI::second))) );
//////////////////////////////////////////////////////
//////////////////////////////////////////////////////

    QMetaObject::connectSlotsByName(this);
    connect(mass_input    , SIGNAL(valueChanged(double)    ), this, SLOT(calc()));
    connect(acc_input     , SIGNAL(valueChanged(double)    ), this, SLOT(calc()));
    connect(force_unit_box, SIGNAL(currentIndexChanged(int)), this, SLOT(calc()));
    connect(acc_unit_box  , SIGNAL(currentIndexChanged(int)), this, SLOT(calc()));
    connect(mass_unit_box , SIGNAL(currentIndexChanged(int)), this, SLOT(calc()));

    QVBoxLayout *layout = new QVBoxLayout;
    layout->addWidget(formWidget);
    setLayout(layout);

    setWindowTitle(tr("units test"));
}

quantity<SI::force> CalculatorForm::newtons_law(const quantity<SI::mass>& m, const quantity<SI::acceleration>& a)
{
    return m*a;
}

void CalculatorForm::calc()
{
    force_txt->setText(QString::number(
        newtons_law(
            mass_input->value() * SI::kilogram * mass_factor() ,
            acc_input->value()  * (SI::meter/(SI::second*SI::second)) * acc_factor() ) 
        / SI::newton / force_factor()
      ));
}
    
// [1]
// in the real world scenario those functions will reduce to an array of conversion
// values, specified by the user from File->Preferences in the software's GUI,
// where he will add new units he wants to use.
//
double CalculatorForm::mass_factor()
{
    return mass_unit_box->itemData(mass_unit_box->currentIndex()).toDouble();
}

double CalculatorForm::acc_factor()
{
    return acc_unit_box->itemData(acc_unit_box->currentIndex()).toDouble();
}

double CalculatorForm::force_factor()
{
    return force_unit_box->itemData(force_unit_box->currentIndex()).toDouble();
}