#ifndef COCKATRICE_QT_UTILS_H
#define COCKATRICE_QT_UTILS_H
#include <QFont>
#include <QFontDatabase>
#include <QLayout>
#include <QObject>
#include <QScrollArea>
#include <QString>
#include <QWidget>

namespace QtUtils
{
/**
 * @brief Returns the nearest ancestor of @p obj that casts to @c T.
 *
 * Walks the QObject parent chain. QWidget::parentWidget() is the same pointer as
 * QObject::parent() for widgets, so this also covers the common "find the parent tab,
 * splitter or scroll area" lookups.
 *
 * @param obj         Object to start from. May be null.
 * @param includeSelf Also test @p obj itself before walking upwards.
 * @return The first matching ancestor, or nullptr if there is none.
 */
template <typename T> T *findParentOfType(const QObject *obj, bool includeSelf = false)
{
    const QObject *p = includeSelf ? obj : (obj ? obj->parent() : nullptr);
    while (p) {
        if (auto casted = qobject_cast<T *>(const_cast<QObject *>(p))) {
            return casted;
        }
        p = p->parent();
    }
    return nullptr;
}

/**
 * @brief How clearLayoutRec() disposes of the widgets it removes.
 *
 * Deferred is the safe default: deleteLater() lets a widget finish handling the event that
 * triggered the rebuild. Use Immediate when the caller rebuilds the same layout right away
 * and a lingering widget would be visible or otherwise in the way until the next event loop
 * turn.
 */
enum class DeletePolicy
{
    Deferred,
    Immediate
};

/**
 * @brief Removes and deletes every item in @p l, recursing into nested layouts.
 *
 * Widgets are disposed of according to @p policy; spacers and nested layouts are simply
 * deleted.
 */
static inline void clearLayoutRec(QLayout *l, DeletePolicy policy = DeletePolicy::Deferred)
{
    if (!l) {
        return;
    }
    while (QLayoutItem *it = l->takeAt(0)) {
        if (QWidget *w = it->widget()) {
            if (policy == DeletePolicy::Immediate) {
                delete w;
            } else {
                w->deleteLater();
            }
        }
        if (QLayout *sub = it->layout()) {
            clearLayoutRec(sub, policy);
        }
        delete it;
    }
}

/**
 * @brief Creates a QScrollArea using the conventions the client applies nearly everywhere:
 *        the inner widget resizes with the viewport and the horizontal bar is disabled.
 *
 * @param parent           Parent widget, or nullptr for a parentless scroll area.
 * @param verticalPolicy   Vertical scroll bar policy.
 * @param horizontalPolicy Horizontal scroll bar policy.
 */
static inline QScrollArea *makeScrollArea(QWidget *parent = nullptr,
                                          Qt::ScrollBarPolicy verticalPolicy = Qt::ScrollBarAsNeeded,
                                          Qt::ScrollBarPolicy horizontalPolicy = Qt::ScrollBarAlwaysOff)
{
    auto *scrollArea = new QScrollArea(parent);
    scrollArea->setWidgetResizable(true);
    scrollArea->setVerticalScrollBarPolicy(verticalPolicy);
    scrollArea->setHorizontalScrollBarPolicy(horizontalPolicy);
    return scrollArea;
}

/**
 * @brief A monospace font at the system UI font's point size.
 *
 * Used for log dumps, deck codes and other text that has to line up.
 */
static inline QFont monospaceFont()
{
    QFont font(QStringLiteral("monospace"));
    font.setStyleHint(QFont::Monospace);
    const int systemPointSize = QFontDatabase::systemFont(QFontDatabase::GeneralFont).pointSize();
    if (systemPointSize > 0) {
        font.setPointSize(systemPointSize);
    }
    return font;
}
} // namespace QtUtils

#endif // COCKATRICE_QT_UTILS_H