#include "ConfigSection.hpp"

#include <QMetaType>
#include <QVariant>

namespace {
// Property index to start scanning from - skips QObject's own "objectName"
// property, which we never want in the JSON.
int firstOwnProperty() {
    return QObject::staticMetaObject.propertyCount();
}
}

ConfigSection::ConfigSection(QObject *parent) : QObject(parent) {}

void ConfigSection::wireSignals() {
    if (m_wired) return;
    m_wired = true;

    const QMetaObject *mo = metaObject();
    const int slotIdx = mo->indexOfSlot("onPropertyChanged()");
    Q_ASSERT(slotIdx != -1);
    const QMetaMethod slot = mo->method(slotIdx);

    const int start = firstOwnProperty();
    for (int i = start; i < mo->propertyCount(); ++i) {
        const QMetaProperty prop = mo->property(i);

        if (prop.metaType().flags().testFlag(QMetaType::PointerToQObject)) {
            if (auto *child = qobject_cast<ConfigSection *>(prop.read(this).value<QObject *>())) {
                // Child sections bubble their changes straight up as our
                // own changed() - no need to also react to our own notify.
                connect(child, &ConfigSection::changed, this, &ConfigSection::changed);
                continue;
            }
        }

        if (prop.hasNotifySignal())
            connect(this, prop.notifySignal(), this, slot);
    }
}

void ConfigSection::onPropertyChanged() {
    Q_EMIT changed();
}

void ConfigSection::fromJson(const QJsonObject &obj) {
    const QMetaObject *mo = metaObject();
    const int start = firstOwnProperty();

    for (int i = start; i < mo->propertyCount(); ++i) {
        const QMetaProperty prop = mo->property(i);
        const QLatin1String name(prop.name());

        if (!obj.contains(name)) continue;

        if (prop.metaType().flags().testFlag(QMetaType::PointerToQObject)) {
            if (auto *child = qobject_cast<ConfigSection *>(prop.read(this).value<QObject *>())) {
                child->fromJson(obj.value(name).toObject());
                continue;
            }
        }

        if (prop.isWritable())
            prop.write(this, obj.value(name).toVariant());
    }
}

QJsonObject ConfigSection::toJson() const {
    QJsonObject obj;
    const QMetaObject *mo = metaObject();
    const int start = firstOwnProperty();

    for (int i = start; i < mo->propertyCount(); ++i) {
        const QMetaProperty prop = mo->property(i);

        if (prop.metaType().flags().testFlag(QMetaType::PointerToQObject)) {
            if (auto *child = qobject_cast<ConfigSection *>(prop.read(this).value<QObject *>())) {
                obj.insert(QLatin1String(prop.name()), child->toJson());
                continue;
            }
        }

        obj.insert(QLatin1String(prop.name()), QJsonValue::fromVariant(prop.read(this)));
    }
    return obj;
}