CalculatorLogic.hpp

#ifndef CALCULATOR_LOGIC_HPP
#define CALCULATOR_LOGIC_HPP

// Include QT API
#include <QString>
#include <QObject>

/**
  * CalculatorLogic - handles calculator logic (div, sub, mult, add, etc).
  *
  * @version 1.0
  * @since 19.07.2019
  * @authors Denis Z. (code4un@yandex.ru)
**/
class CalculatorLogic : public QObject
{

    // -----------------------------------------------------------

    // ===========================================================
    // QT MACROS
    // ===========================================================

    Q_OBJECT

    // -----------------------------------------------------------

private:

    // -----------------------------------------------------------

    // ===========================================================
    // CONSTANTS
    // ===========================================================

    /** NONE **/
    static const unsigned char NONE_OPERATION_TYPE = 0;

    /** + **/
    static const unsigned char SUM_OPERATION_TYPE = 1;

    /** - **/
    static const unsigned char SUB_OPERATION_TYPE = 2;

    /** / **/
    static const unsigned char DIV_OPERATION_TYPE = 3;

    /** * **/
    static const unsigned char MUL_OPERATION_TYPE = 4;

    /** sqrt **/
    static const unsigned char SQRT_OPERATION_TYPE = 5;

    // ===========================================================
    // FIELDS
    // ===========================================================

    /** Stored Value. **/
    QString mStoredValue;

    /** First argument. **/
    QString mLeftArg;

    /** Right Argument **/
    QString mRightArg;

    /** Cached Output-String. **/
    QString mOutput;

    /** Operation-Type **/
    unsigned char mOperationType;

    // ===========================================================
    // METHODS
    // ===========================================================

    /**
      * Updates Output-string.
      *
      * @thread_safety - not thread-safe.
      * @throws - no exceptions.
    **/
    void onUpdateOutput( ) noexcept;

    /**
      * Called to clear (reset) state after calculation.
      *
      * (?) Unlikely #resetLogic() this method doesn't resets
      * stored items & output.
      *
      * @thread_safety - not thread-safe.
      * @throws - no exceptions.
    **/
    void onCalculationDone( ) noexcept;

    // -----------------------------------------------------------

public:

    // -----------------------------------------------------------

    // ===========================================================
    // CONSTRUCTOR
    // ===========================================================

    /**
      * CalculatorLogic constructor.
      *
      * @param qParent - parent-QObject, default is null.
      * @throws - no exceptions.
    **/
    explicit CalculatorLogic( QObject *const qParent = nullptr ) noexcept;

    // ===========================================================
    // DESTRUCTOR
    // ===========================================================

    /**
      * CalculatorLogic destructor.
      *
      * @throws - no exceptions.
    **/
    virtual ~CalculatorLogic( ) noexcept;

    // ===========================================================
    // GETTERS & SETTERS
    // ===========================================================

    /**
      * Called when operation (div, sub, sum, etc) called.
      *
      * @thread_safety - not thread-safe.
      * @param pType - operation-type in string-format ("+", "/", etc).
      * @returns - output-string to be displayed.
      * @throws - no exceptions.
    **/
    Q_INVOKABLE QString setOperationType( const QString pType ) noexcept;

    // ===========================================================
    // METHODS
    // ===========================================================

    /**
      * Called when dot (separator) requested.
      *
      * @thread_safety - not thread-safe.
      * @returns - output-string to be displayed.
      * @throws - no exceptions.
    **/
    Q_INVOKABLE QString onDot( ) noexcept;

    /**
      * Called when QML Keyboard Inuput-Event handled.
      *
      * @thread_safety - not thread-safe.
      * @returns - output-string to be displayed.
      * @throws - no exceptions.
    **/
    Q_INVOKABLE QString onKeyboardInput( const QString pValue ) noexcept;

    /**
      * Called when number added to argument.
      *
      * @thread_safety - not thread-safe.
      * @param pNumber - number to add.
      * @returns - output-string to be displayed.
      * @throws - no exceptions.
    **/
    Q_INVOKABLE QString onNumberInput( const QString pNumber ) noexcept;

    /**
      * Called to replace Right-Argument with Memory-Item.
      *
      * @thread_safety - not thread-safe.
      * @returns - output-string to be displayed.
      * @throws - no exceptions.
    **/
    Q_INVOKABLE QString onMR( ) noexcept;

    /**
      * Sets Memory-Item.
      *
      * @thread_safety - not thread-safe.
      * @throws - no exceptions.
    **/
    Q_INVOKABLE void onMS( ) noexcept;

    /**
      * Called when last argument-number requested (erase, chop).
      *
      * @thread_safety - not thread-safe.
      * @returns - output-string to be displayed.
      * @throws - no exceptions.
    **/
    Q_INVOKABLE QString onRemoveLastNumber( ) noexcept;

    /**
      * Calculates result using two arguments & operation-type.
      *
      * @thread_safety - not thread-safe.
      * @return - result in string-type.
      * @throws - no exceptions.
    **/
    Q_INVOKABLE QString doMath( ) noexcept;

    /**
      * Resets stored values.
      *
      * @thread_safety - not thread-safe.
      * @throws - no exceptions.
    **/
    Q_INVOKABLE void resetMemory( ) noexcept;

    /**
      * Reset Calculator Logic State.
      *
      * @thread_safety - not thread-safe.
      * @throws - no exceptions.
    **/
    Q_INVOKABLE void resetLogic( ) noexcept;

    // -----------------------------------------------------------

};


#endif // !CALCULATOR_LOGIC_HPP