#include "calc.h"

Calculator::Calculator(QWidget *wgt)
{
    m_plcd = new QLCDNumber(12);
    m_plcd->setSegmentStyle(QLCDNumber::Flat);
    m_plcd->setMinimumSize(150, 50);

    QChar aButtons[4][4] = {{'7', '8', '9', '/'},
                            {'4', '5', '6', '*'},
                            {'1', '2', '3', '-'},
                            {'0', '.', '=', '+'}};

    QGridLayout *ptopLayout = new QGridLayout;
    ptopLayout->addWidget(m_plcd, 0, 0, 1, 4);
    ptopLayout->addWidget(createButton("CE"), 1, 3);

    for (int i = 0; i < 4; ++i)
    {
        for (int j = 0; j < 4; ++j)
        {
            ptopLayout->addWidget(createButton(aButtons[i][j]), i + 2, j);
        }
    }
    setLayout(ptopLayout);
}

QPushButton* Calculator::createButton(const QString& str)
{
    QPushButton *pcmd = new QPushButton(str);
    pcmd->setMinimumSize(40, 40);
    connect(pcmd, SIGNAL(clicked), SLOT(slotButtonClicked));
    return pcmd;
}

void Calculator::calculate()
{
    double dOperand2 = m_stk.pop().toDouble();
    QString strOperation = m_stk.pop();
    double dOperand1 = m_stk.pop().toDouble();
    double dResult = 0;

    if(strOperation == "+")
    {
        dResult = dOperand1 + dOperand2;
    }
    if(strOperation == "-")
    {
        dResult = dOperand1 - dOperand2;
    }
    if(strOperation == "/")
    {
        dResult = dOperand1 / dOperand2;
    }
    if(strOperation == "*")
    {
        dResult = dOperand1 * dOperand2;
    }

    m_plcd->display(dResult);
}

void Calculator::slotButtonClicked()
{
    QString str = ((QPushButton *)sender())->text();

    if (str == "CE")
    {
        m_stk.clear();
        m_strDisplay = "";
        m_plcd->display("0");
        return;
    }
    if (str.contains(QRegExp("[0-9]")))
    {
        m_strDisplay += str;
        m_plcd->display(m_strDisplay.toDouble());
    }
    else if (str == ".")
    {
        m_strDisplay += str;
        m_plcd->display(m_strDisplay);
    }
    else
    {
        if (m_stk.count() >= 2)
        {
            m_stk.push(QString.setNum(m_plcd->value()));
            calculate();
            m_stk.clear();
            m_stk.push(QString.setNum(m_plcd.value()));
            if (str != "=")
            {
                m_stk.push(str);
            }
        }
        else
        {
            m_stk.push(QString().setNum(m_plcd->value()));
            m_strDisplay = "";
            m_plcd->display("0");
        }
    }
}