#include "cwidget.h"

#define KEY_CLR   "CLR"
#define KEY_ADD   "+"
#define KEY_SUB   "-"
#define KEY_MUL   "*"
#define KEY_DIV   "/"
#define KEY_EQ    "="
#define KEY_0     "0"
#define KEY_1     "1"
#define KEY_2     "2"
#define KEY_3     "3"
#define KEY_4     "4"
#define KEY_5     "5"
#define KEY_6     "6"
#define KEY_7     "7"
#define KEY_8     "8"
#define KEY_9     "9"

#define BUTTONWIDTH 30
#define BUTTONHEIGHT 30

static char *buttontext[] = 
{
	KEY_1,KEY_2,KEY_3,KEY_4,
	KEY_5,KEY_6,KEY_7,KEY_8,
	KEY_9,KEY_ADD,KEY_SUB,KEY_MUL,
	KEY_DIV,KEY_EQ,KEY_CLR,KEY_0
};

CWidget::CWidget(QWidget *parent, char *name)
{
	initialize();
	createForm();
}

CWidget::~CWidget()
{
	delete edit;
	delete *button;
	delete mainLayout;
	delete topLayout;
	delete bottomLayout;
}

void CWidget::calculate()
{
	switch(oper)
	{
		case Qt::Key_Plus:
			firstNum += secondNum;break;
		case Qt::Key_Minus:
			firstNum -= secondNum;break;
		case Qt::Key_Asterisk:
			firstNum *= secondNum;break;
		case Qt::Key_Slash:
			firstNum /= secondNum;break;
		default:
			firstNum = firstNum;
	}
	edit->setText(QString::number(firstNum));
}

void CWidget::setValue()
{
	QString tempStr;
	tempStr = edit->text();
	if(tempStr.length() < edit->maxLength())
		tempStr += ((QPushButton *)sender())->text();
	else
		{
			QMessageBox::information( this, tr("Calculator"),tr("too long!"));
		}
	if(-1==oper)
	{
		firstNum = tempStr.toInt();
		edit->setText(QString::number(firstNum));
	}
	else
	{
		secondNum = tempStr.toInt();
		edit->setText(QString::number(secondNum));
	}
}

void CWidget::setOper()
{
	QString str=((QPushButton *)sender())->text();
	if(str == "+")
		onClicked(Qt::Key_Plus);
	else if(str == "-")
		onClicked(Qt::Key_Minus);
	else if(str == "*")
		onClicked(Qt::Key_Asterisk);
	else if(str == "/")
		onClicked(Qt::Key_Slash);
	else if(str == "=")
		calculate();
}

void CWidget::clear()
{
	edit->clear();
	edit->setText(tr("%1").arg(0));
	initialize();
}

void CWidget::initialize()
{
	firstNum = 0;
	secondNum = 0;
	oper = -1;
}

void CWidget::createForm()
{
	setMinimumSize(80,200);
	setMaximumSize(80,200);
	  
  mainLayout = new QVBoxLayout(this,20);
  topLayout = new QHBoxLayout(mainLayout,30);
	edit = new QLineEdit(this,"edit");
	edit->setAlignment(Qt::AlignRight);
	edit->setMaxLength(9);
	edit->setText(tr("%1").arg(0));
	edit->setReadOnly(true);
  topLayout->addWidget(edit);
  bottomLayout = new QGridLayout(mainLayout,4,4,10);
  int n;
  for(int r=0; r<3; r++)
  	for(int c=0; c<3; c++)
  	{
  		n = c+3*r;
  		button[n] = new QPushButton(buttontext[n],this,buttontext[n]);
  		button[n]->setFixedSize(BUTTONWIDTH,BUTTONHEIGHT);
  		bottomLayout->addWidget(button[n],r,c);
  		connect(button[n],SIGNAL(clicked()),this,SLOT(setValue()));
  	}
  button[9] = new QPushButton(buttontext[9],this,buttontext[9]);
  button[9]->setFixedSize(BUTTONWIDTH,BUTTONHEIGHT);
  bottomLayout->addWidget(button[9],0,3);
  connect(button[9],SIGNAL(clicked()),this,SLOT(setOper()));
  
  button[10] = new QPushButton(buttontext[10],this,buttontext[10]);
  button[10]->setFixedSize(BUTTONWIDTH,BUTTONHEIGHT);
  bottomLayout->addWidget(button[10],1,3);
  connect(button[10],SIGNAL(clicked()),this,SLOT(setOper()));
  
  button[11] = new QPushButton(buttontext[11],this,buttontext[11]);
  button[11]->setFixedSize(BUTTONWIDTH,BUTTONHEIGHT);
  bottomLayout->addWidget(button[11],2,3);
  connect(button[11],SIGNAL(clicked()),this,SLOT(setOper()));
  
  button[12] = new QPushButton(buttontext[12],this,buttontext[12]);
  button[12]->setFixedSize(BUTTONWIDTH,BUTTONHEIGHT);
  bottomLayout->addWidget(button[12],3,3);
  connect(button[12],SIGNAL(clicked()),this,SLOT(setOper()));
  
  button[13] = new QPushButton(buttontext[13],this,buttontext[13]);
  button[13]->setFixedSize(BUTTONWIDTH,BUTTONHEIGHT);
  bottomLayout->addWidget(button[13],3,2);
  connect(button[13],SIGNAL(clicked()),this,SLOT(calculate()));
  
  button[14] = new QPushButton(buttontext[14],this,buttontext[14]);
  button[14]->setFixedSize(BUTTONWIDTH,BUTTONHEIGHT);
  bottomLayout->addWidget(button[14],3,1);
  connect(button[14],SIGNAL(clicked()),this,SLOT(clear()));

  button[15] = new QPushButton(buttontext[15],this,buttontext[14]);
  button[15]->setFixedSize(BUTTONWIDTH,BUTTONHEIGHT);
  bottomLayout->addWidget(button[15],3,0);
  connect(button[15],SIGNAL(clicked()),this,SLOT(setValue()));
}

bool CWidget::event(QEvent *e)
{
	if(e->type() == QEvent::KeyPress)
	{
		QKeyEvent *KeyEvent = static_cast<QKeyEvent*>(e);
		switch(KeyEvent->key())
		{
			case Qt::Key_Plus:
				onClicked(Qt::Key_Plus);break;
			case Qt::Key_Minus:
				onClicked(Qt::Key_Minus);break;
			case Qt::Key_Asterisk:
				onClicked(Qt::Key_Asterisk);break;
			case Qt::Key_Slash:
				onClicked(Qt::Key_Slash);break;
			case Qt::Key_Equal:
				calculate();break;
		}
	}
	return QWidget::event(e);
}

void CWidget::onClicked(int key)
{	
	edit->clear();
	edit->setText(tr("%1").arg(0));
	oper = key;
}