#ifndef OPTIONSPAGE_H
#define OPTIONSPAGE_H

#include <c++utilities/application/global.h>

#include <QObject>
#include <QWidget>

#include <memory>

namespace Dialogs {

class LIB_EXPORT OptionPage
{
public:
    explicit OptionPage(QWidget *parentWindow = nullptr);
    virtual ~OptionPage();

    QWidget *parentWindow() const;
    QWidget *widget();
    bool hasBeenShown() const;
    virtual bool apply() = 0;
    virtual void reset() = 0;
    bool matches(const QString &searchKeyWord);
    const QStringList &errors() const;

protected:
    virtual QWidget *setupWidget() = 0;
    QStringList &errors();

private:
    std::unique_ptr<QWidget> m_widget;
    QWidget *m_parentWindow;
    bool m_shown;
    bool m_keywordsInitialized;
    QStringList m_keywords;
    QStringList m_errors;
};

/*!
 * \brief Returns the parent window of the option page.
 */
inline QWidget *OptionPage::parentWindow() const
{
    return m_parentWindow;
}

/*!
 * \brief Returns an indication whether the option page has been shown yet.
 */
inline bool OptionPage::hasBeenShown() const
{
    return m_widget != nullptr && m_shown;
}

/*!
 * \brief Returns the errors which haven been occurred when applying the changes.
 */
inline const QStringList &OptionPage::errors() const
{
    return m_errors;
}

/*!
 * \brief Returns the errors which haven been occurred when applying the changes.
 *
 * Error messages should be added when implementing apply() and something goes wrong.
 * In this case, apply() should return false.
 */
inline QStringList &OptionPage::errors()
{
    return m_errors;
}

/*!
 * \class Dialogs::UiFileBasedOptionPage
 * \brief The UiFileBasedOptionPage class is the base class for SettingsDialog pages using UI files
 *        to describe the widget tree.
 *
 * \tparam UiClass Specifies the UI class generated by uic.
 */
template <class UiClass>
class LIB_EXPORT UiFileBasedOptionPage : public OptionPage
{
public:
    explicit UiFileBasedOptionPage(QWidget *parentWindow = nullptr);
    virtual ~UiFileBasedOptionPage();

    virtual bool apply() = 0;
    virtual void reset() = 0;

protected:
    virtual QWidget *setupWidget();
    UiClass *ui();

private:
    std::unique_ptr<UiClass> m_ui;
};

/*!
 * \brief Constructs a new UI file based option page.
 */
template <class UiClass>
UiFileBasedOptionPage<UiClass>::UiFileBasedOptionPage(QWidget *parentWindow) :
    OptionPage(parentWindow)
{}

/*!
 * \brief Destroys the option page.
 */
template <class UiClass>
UiFileBasedOptionPage<UiClass>::~UiFileBasedOptionPage()
{}

/*!
 * \brief Sets up the widget for the option page using the UI class.
 */
template <class UiClass>
QWidget *UiFileBasedOptionPage<UiClass>::setupWidget()
{
    QWidget *widget = new QWidget();
    if(!m_ui) {
        m_ui.reset(new UiClass);
    }
    m_ui->setupUi(widget);
    return widget;
}

template <class UiClass>
inline UiClass *UiFileBasedOptionPage<UiClass>::ui()
{
    return m_ui.get();
}

}

#define BEGIN_DECLARE_OPTION_PAGE(SomeClass) \
    class SomeClass : public ::Dialogs::OptionPage \
    { \
    public: \
        explicit SomeClass(QWidget *parentWidget = nullptr); \
        ~SomeClass(); \
        bool apply(); \
        void reset(); \
    private:

#define BEGIN_DECLARE_UI_FILE_BASED_OPTION_PAGE(SomeClass) \
    namespace Ui { \
    class SomeClass; \
    } \
    typedef ::Dialogs::UiFileBasedOptionPage<Ui::SomeClass> SomeClass ## Base; \
    class SomeClass : public ::Dialogs::UiFileBasedOptionPage<Ui::SomeClass> \
    { \
    public: \
        explicit SomeClass(QWidget *parentWidget = nullptr); \
        ~SomeClass(); \
        bool apply(); \
        void reset(); \
    private:

#define END_DECLARE_OPTION_PAGE \
    };

#define DECLARE_SETUP_WIDGETS \
    protected: \
        QWidget *setupWidget(); \
    private:

#define DECLARE_UI_FILE_BASED_OPTION_PAGE(SomeClass) \
    BEGIN_DECLARE_UI_FILE_BASED_OPTION_PAGE(SomeClass) \
    END_DECLARE_OPTION_PAGE

#define DECLARE_UI_FILE_BASED_OPTION_PAGE_CUSTOM_SETUP(SomeClass) \
    BEGIN_DECLARE_UI_FILE_BASED_OPTION_PAGE(SomeClass) \
        DECLARE_SETUP_WIDGETS \
    END_DECLARE_OPTION_PAGE

#endif // OPTIONSPAGE_H