class Calculator

# File examples/widgets/calculator/calculator.rb, line 47
def initialize(parent = nil)
    super(parent)
    @sumInMemory = 0.0
    @sumSoFar = 0.0
    @factorSoFar = 0.0
    @waitingForOperand = true

    @display = Qt::LineEdit.new("0")
    @display.readOnly = true
    @display.alignment = Qt::AlignRight
    @display.maxLength = 15
    @display.installEventFilter(self)

    font = @display.font()
    font.pointSize += 8
    @display.font = font

    digitColor = Qt::Color.new(150, 205, 205)
    backspaceColor = Qt::Color.new(225, 185, 135)
    memoryColor = Qt::Color.new(100, 155, 155)
    operatorColor = Qt::Color.new(155, 175, 195)

    @digitButtons = []
    (0...NumDigitButtons).each do |i|
        @digitButtons[i] = createButton("%d" % i, digitColor,
                                    SLOT('digitClicked()'))
    end

    @pointButton = createButton(tr("."), digitColor, SLOT('pointClicked()'))
    @changeSignButton = createButton(tr("\261"), digitColor, SLOT('changeSignClicked()'))

    @backspaceButton = createButton(tr("Backspace"), backspaceColor,
                                SLOT('backspaceClicked()'))
    @clearButton = createButton(tr("Clear"), backspaceColor, SLOT('clear()'))
    @clearAllButton = createButton(tr("Clear All"), backspaceColor.light(120),
                                SLOT('clearAll()'))

    @clearMemoryButton = createButton(tr("MC"), memoryColor,
                                    SLOT('clearMemory()'))
    @readMemoryButton = createButton(tr("MR"), memoryColor, SLOT('readMemory()'))
    @setMemoryButton = createButton(tr("MS"), memoryColor, SLOT('setMemory()'))
    @addToMemoryButton = createButton(tr("M+"), memoryColor,
                                    SLOT('addToMemory()'))

    @divisionButton = createButton(tr("\367"), operatorColor,
                                SLOT('multiplicativeOperatorClicked()'))
    @timesButton = createButton(tr("\327"), operatorColor,
                            SLOT('multiplicativeOperatorClicked()'))
    @minusButton = createButton(tr("-"), operatorColor,
                            SLOT('additiveOperatorClicked()'))
    @plusButton = createButton(tr("+"), operatorColor,
                            SLOT('additiveOperatorClicked()'))

    @squareRootButton = createButton(tr("Sqrt"), operatorColor,
                                    SLOT('unaryOperatorClicked()'))
    @powerButton = createButton(tr("x\262"), operatorColor,
                            SLOT('unaryOperatorClicked()'))
    @reciprocalButton = createButton(tr("1/x"), operatorColor,
                                    SLOT('unaryOperatorClicked()'))
    @equalButton = createButton(tr("="), operatorColor.light(120),
                            SLOT('equalClicked()'))

    mainLayout = Qt::GridLayout.new
    mainLayout.SizeConstraint = Qt::Layout::SetFixedSize

    mainLayout.addWidget(@display, 0, 0, 1, 6)
    mainLayout.addWidget(@backspaceButton, 1, 0, 1, 2)
    mainLayout.addWidget(@clearButton, 1, 2, 1, 2)
    mainLayout.addWidget(@clearAllButton, 1, 4, 1, 2)

    mainLayout.addWidget(@clearMemoryButton, 2, 0)
    mainLayout.addWidget(@readMemoryButton, 3, 0)
    mainLayout.addWidget(@setMemoryButton, 4, 0)
    mainLayout.addWidget(@addToMemoryButton, 5, 0)

    for i in 1...NumDigitButtons
        row = ((9 - i) / 3) + 2
        column = ((i - 1) % 3) + 1
        mainLayout.addWidget(@digitButtons[i], row, column)
    end

    mainLayout.addWidget(@digitButtons[0], 5, 1)
    mainLayout.addWidget(@pointButton, 5, 2)
    mainLayout.addWidget(@changeSignButton, 5, 3)

    mainLayout.addWidget(@divisionButton, 2, 4)
    mainLayout.addWidget(@timesButton, 3, 4)
    mainLayout.addWidget(@minusButton, 4, 4)
    mainLayout.addWidget(@plusButton, 5, 4)

    mainLayout.addWidget(@squareRootButton, 2, 5)
    mainLayout.addWidget(@powerButton, 3, 5)
    mainLayout.addWidget(@reciprocalButton, 4, 5)
    mainLayout.addWidget(@equalButton, 5, 5)
    setLayout(mainLayout)

    setWindowTitle(tr("Calculator"))
end

# File examples/widgets/calculator/calculator.rb, line 362
def abortOperation()
    clearAll()
    @display.text = tr("####")
end

# File examples/widgets/calculator/calculator.rb, line 351
def addToMemory()
    equalClicked()
    @sumInMemory += @display.text().to_f
end

# File examples/widgets/calculator/calculator.rb, line 208
def additiveOperatorClicked()
    clickedButton = sender()
    clickedOperator = clickedButton.text()
    operand = @display.text().to_f

    if !@pendingMultiplicativeOperator.nil?
        if !calculate(operand, @pendingMultiplicativeOperator)
            abortOperation()
            return
        end
        @display.text = @factorSoFar.to_s
        operand = @factorSoFar
        @factorSoFar = 0.0
        @pendingMultiplicativeOperator = nil
    end

    if !@pendingAdditiveOperator.nil?
        if !calculate(operand, @pendingAdditiveOperator)
            abortOperation()
            return
        end
        @display.text = @sumSoFar.to_s
    else
        @sumSoFar = operand
    end

    @pendingAdditiveOperator = clickedOperator
    @waitingForOperand = true
end

# File examples/widgets/calculator/calculator.rb, line 306
def backspaceClicked()
    if @waitingForOperand
        return
    end
    text = @display.text()
    text.chop!
    if text.empty?
        text = "0"
        @waitingForOperand = true
    end
    @display.text = text
end

# File examples/widgets/calculator/calculator.rb, line 367
def calculate(rightOperand, pendingOperator)
    if pendingOperator == tr("+")
        @sumSoFar += rightOperand
    elsif pendingOperator == tr("-")
        @sumSoFar -= rightOperand
    elsif pendingOperator == tr("\327")
        @factorSoFar *= rightOperand
    elsif pendingOperator == tr("\367")
        if rightOperand == 0.0
            return false
        end
        @factorSoFar /= rightOperand
    end
    return true
end

# File examples/widgets/calculator/calculator.rb, line 294
def changeSignClicked()
    text = @display.text()
    value = text.to_f

    if value > 0.0
        text.insert(0, tr("-"))
    elsif value < 0.0
        text = text[1, text.length - 1]
    end
    @display.text = text
end

# File examples/widgets/calculator/calculator.rb, line 319
def clear()
    if @waitingForOperand
        return
    end

    @display.text = "0"
    @waitingForOperand = true
end

# File examples/widgets/calculator/calculator.rb, line 328
def clearAll()
    @sumSoFar = 0.0
    @factorSoFar = 0.0
    @pendingAdditiveOperator= nil
    @pendingMultiplicativeOperator= nil
    @display.text = "0"
    @waitingForOperand = true
end

# File examples/widgets/calculator/calculator.rb, line 337
def clearMemory()
    @sumInMemory = 0.0
end

# File examples/widgets/calculator/calculator.rb, line 356
def createButton(text, color, member)
    button = CalcButton.new(text, color)
    connect(button, SIGNAL('clicked()'), self, member)
    return button
end

# File examples/widgets/calculator/calculator.rb, line 169
def digitClicked()
    clickedButton = sender()
    digitValue = clickedButton.text().to_i
    if @display.text() == "0" && digitValue == 0
        return
    end

    if @waitingForOperand
        @display.clear()
        @waitingForOperand = false
    end
    @display.text += digitValue.to_s
end

# File examples/widgets/calculator/calculator.rb, line 257
def equalClicked()
    operand = @display.text().to_f

    if !@pendingMultiplicativeOperator.nil?
        if !calculate(operand, @pendingMultiplicativeOperator)
            abortOperation()
            return
        end
        operand = @factorSoFar
        @factorSoFar = 0.0
        @pendingMultiplicativeOperator= nil
    end
    if !@pendingAdditiveOperator.nil?
        if !calculate(operand, @pendingAdditiveOperator)
            abortOperation()
            return
        end
        @pendingAdditiveOperator = nil
    else
        @sumSoFar = operand
    end

    @display.text = @sumSoFar.to_s
    @sumSoFar = 0.0
    @waitingForOperand = true
end

# File examples/widgets/calculator/calculator.rb, line 146
def eventFilter(target, event)
    if target == @display
        if event.type() == Qt::Event::MouseButtonPress ||
                event.type() == Qt::Event::MouseButtonDblClick ||
                event.type() == Qt::Event::MouseButtonRelease ||
                event.type() == Qt::Event::ContextMenu 
            mouseEvent = Qt::Internal.cast_object_to(event, Qt::MouseEvent)
            if mouseEvent.buttons() & Qt::LeftButton.to_i != 0
                newPalette = palette()
                newPalette.setColor(Qt::Palette::Base,
                                    @display.palette().color(Qt::Palette::Text))
                newPalette.setColor(Qt::Palette::Text,
                                    @display.palette().color(Qt::Palette::Base))
                @display.palette = newPalette
            else
                @display.palette = palette()
            end
            return true
        end
    end
    super(target, event)
end

# File examples/widgets/calculator/calculator.rb, line 238
def multiplicativeOperatorClicked()
    clickedButton = sender()
    clickedOperator = clickedButton.text()
    operand = @display.text().to_f

    if !@pendingMultiplicativeOperator.nil?
        if !calculate(operand, @pendingMultiplicativeOperator)
            abortOperation()
            return
        end
        @display.text = @factorSoFar.to_s
    else
        @factorSoFar = operand
    end

    @pendingMultiplicativeOperator = clickedOperator
    @waitingForOperand = true
end

# File examples/widgets/calculator/calculator.rb, line 284
def pointClicked()
    if @waitingForOperand
        @display.text = "0"
    end
    if !@display.text().include? "."
        @display.text += tr(".")
    end
    @waitingForOperand = false
end

# File examples/widgets/calculator/calculator.rb, line 341
def readMemory()
    @display.text = @sumInMemory.to_s
    @waitingForOperand = true
end

# File examples/widgets/calculator/calculator.rb, line 346
def setMemory()
    equalClicked()
    @sumInMemory = @display.text().to_f
end

# File examples/widgets/calculator/calculator.rb, line 183
def unaryOperatorClicked()
    clickedButton = sender()
    clickedOperator = clickedButton.text()
    operand = @display.text().to_f
    result

    if clickedOperator == tr("Sqrt")
        if operand < 0.0
            abortOperation()
            return
        end
        result = Math.sqrt(operand)
    elsif clickedOperator == tr("x\262")
        result = operand ** 2.0
    elsif clickedOperator == tr("1/x")
        if operand == 0.0
            abortOperation()
            return
        end
        result = 1.0 / operand
    end
    @display.text = result.to_s
    @waitingForOperand = true
end