Start to split widget here too

src/collectionpage/collectionviewwidget.cpp

+/*
+   SPDX-FileCopyrightText: 2020 Laurent Montel <montel@kde.org>
+
+   SPDX-License-Identifier: GPL-2.0-or-later
+*/
+
+#include "collectionviewwidget.h"
+#include <QVBoxLayout>
+#include <KLocalizedString>
+#include <QLabel>
+#include <QComboBox>
+#include <QGroupBox>
+#include <QCheckBox>
+
+CollectionViewWidget::CollectionViewWidget(QWidget *parent)
+    : QWidget(parent)
+{
+    QVBoxLayout *topLayout = new QVBoxLayout(this);
+    topLayout->setObjectName(QStringLiteral("topLayout"));
+    topLayout->setContentsMargins({});
+
+    // sender or receiver column
+    const QString senderReceiverColumnTip = i18n("Show Sender/Receiver Column in List of Messages");
+
+    QLabel *senderReceiverColumnLabel = new QLabel(i18n("Sho&w column:"), this);
+    mShowSenderReceiverComboBox = new QComboBox(this);
+    mShowSenderReceiverComboBox->setToolTip(senderReceiverColumnTip);
+    senderReceiverColumnLabel->setBuddy(mShowSenderReceiverComboBox);
+    mShowSenderReceiverComboBox->insertItem(0, i18nc("@item:inlistbox Show default value.", "Default"));
+    mShowSenderReceiverComboBox->insertItem(1, i18nc("@item:inlistbox Show sender.", "Sender"));
+    mShowSenderReceiverComboBox->insertItem(2, i18nc("@item:inlistbox Show receiver.", "Receiver"));
+
+    QHBoxLayout *senderReceiverColumnHLayout = new QHBoxLayout();
+    senderReceiverColumnHLayout->addWidget(senderReceiverColumnLabel);
+    senderReceiverColumnHLayout->addWidget(mShowSenderReceiverComboBox);
+    topLayout->addLayout(senderReceiverColumnHLayout);
+
+    // message list
+    QGroupBox *messageListGroup = new QGroupBox(i18n("Message List"), this);
+    QVBoxLayout *messageListGroupLayout = new QVBoxLayout(messageListGroup);
+    topLayout->addWidget(messageListGroup);
+
+    // message list aggregation
+    mUseDefaultAggregationCheckBox = new QCheckBox(i18n("Use default aggregation"), messageListGroup);
+    messageListGroupLayout->addWidget(mUseDefaultAggregationCheckBox);
+    connect(mUseDefaultAggregationCheckBox, &QCheckBox::stateChanged, this, &CollectionViewPage::slotAggregationCheckboxChanged);
+
+    mAggregationComboBox = new MessageList::Utils::AggregationComboBox(messageListGroup);
+
+    QLabel *aggregationLabel = new QLabel(i18n("Aggregation"), messageListGroup);
+    aggregationLabel->setBuddy(mAggregationComboBox);
+
+    using MessageList::Utils::AggregationConfigButton;
+    AggregationConfigButton *aggregationConfigButton = new AggregationConfigButton(messageListGroup, mAggregationComboBox);
+    // Make sure any changes made in the aggregations configure dialog are reflected in the combo.
+    connect(aggregationConfigButton, &AggregationConfigButton::configureDialogCompleted, this, &CollectionViewPage::slotSelectFolderAggregation);
+
+    QHBoxLayout *aggregationLayout = new QHBoxLayout();
+    aggregationLayout->addWidget(aggregationLabel, 1);
+    aggregationLayout->addWidget(mAggregationComboBox, 1);
+    aggregationLayout->addWidget(aggregationConfigButton, 0);
+    messageListGroupLayout->addLayout(aggregationLayout);
+
+    // message list theme
+    mUseDefaultThemeCheckBox = new QCheckBox(i18n("Use default theme"), messageListGroup);
+    messageListGroupLayout->addWidget(mUseDefaultThemeCheckBox);
+    connect(mUseDefaultThemeCheckBox, &QCheckBox::stateChanged, this, &CollectionViewPage::slotThemeCheckboxChanged);
+
+    mThemeComboBox = new MessageList::Utils::ThemeComboBox(messageListGroup);
+
+    QLabel *themeLabel = new QLabel(i18n("Theme"), messageListGroup);
+    themeLabel->setBuddy(mThemeComboBox);
+
+    using MessageList::Utils::ThemeConfigButton;
+    ThemeConfigButton *themeConfigButton = new ThemeConfigButton(messageListGroup, mThemeComboBox);
+    // Make sure any changes made in the themes configure dialog are reflected in the combo.
+    connect(themeConfigButton, &ThemeConfigButton::configureDialogCompleted, this, &CollectionViewPage::slotSelectFolderTheme);
+
+    QHBoxLayout *themeLayout = new QHBoxLayout();
+    themeLayout->addWidget(themeLabel, 1);
+    themeLayout->addWidget(mThemeComboBox, 1);
+    themeLayout->addWidget(themeConfigButton, 0);
+    messageListGroupLayout->addLayout(themeLayout);
+
+    // Message Default Format
+    QGroupBox *messageFormatGroup = new QGroupBox(i18n("Message Default Format"), this);
+    QVBoxLayout *messageFormatGroupLayout = new QVBoxLayout(messageFormatGroup);
+    mPreferHtmlToText = new QRadioButton(i18n("Prefer HTML to text"), this);
+    messageFormatGroupLayout->addWidget(mPreferHtmlToText);
+    mPreferTextToHtml = new QRadioButton(i18n("Prefer text to HTML"), this);
+    messageFormatGroupLayout->addWidget(mPreferTextToHtml);
+    mUseGlobalSettings = new QRadioButton(i18n("Use Global Settings"), this);
+    messageFormatGroupLayout->addWidget(mUseGlobalSettings);
+
+    topLayout->addWidget(messageFormatGroup);
+
+    topLayout->addStretch(100);
+
+    //TODO
+}
+
+CollectionViewWidget::~CollectionViewWidget()
+{
+
+}
+
+void CollectionViewWidget::load(const Akonadi::Collection &col)
+{
+    if (col.hasAttribute<Akonadi::MessageFolderAttribute>()) {
+        const bool outboundFolder = col.attribute<Akonadi::MessageFolderAttribute>()->isOutboundFolder();
+        if (outboundFolder) {
+            mShowSenderReceiverComboBox->setCurrentIndex(2);
+        } else {
+            mShowSenderReceiverComboBox->setCurrentIndex(1);
+        }
+    } else {
+        mShowSenderReceiverComboBox->setCurrentIndex(0);
+    }
+    mShowSenderReceiverValue = mShowSenderReceiverComboBox->currentIndex();
+
+    // message list aggregation
+    slotSelectFolderAggregation();
+
+    // message list theme
+    slotSelectFolderTheme();
+
+    const MessageViewer::Viewer::DisplayFormatMessage formatMessage = mFolderCollection->formatMessage();
+    switch (formatMessage) {
+    case MessageViewer::Viewer::Html:
+        mPreferHtmlToText->setChecked(true);
+        break;
+    case MessageViewer::Viewer::Text:
+        mPreferTextToHtml->setChecked(true);
+        break;
+    case MessageViewer::Viewer::UseGlobalSetting:
+        mUseGlobalSettings->setChecked(true);
+        break;
+    default:
+        qCDebug(KMAIL_LOG) << "No settings defined";
+        break;
+    }
+}
+
+void CollectionViewWidget::save(Akonadi::Collection &col)
+{
+    const int currentIndex = mShowSenderReceiverComboBox->currentIndex();
+    if (mShowSenderReceiverValue != currentIndex) {
+        if (currentIndex == 1) {
+            Akonadi::MessageFolderAttribute *messageFolder = col.attribute<Akonadi::MessageFolderAttribute>(Akonadi::Collection::AddIfMissing);
+            messageFolder->setOutboundFolder(false);
+        } else if (currentIndex == 2) {
+            Akonadi::MessageFolderAttribute *messageFolder = col.attribute<Akonadi::MessageFolderAttribute>(Akonadi::Collection::AddIfMissing);
+            messageFolder->setOutboundFolder(true);
+        } else {
+            col.removeAttribute<Akonadi::MessageFolderAttribute>();
+        }
+    }
+    // message list theme
+    const bool usePrivateTheme = !mUseDefaultThemeCheckBox->isChecked();
+    mThemeComboBox->writeStorageModelConfig(QString::number(mCurrentCollection.id()), usePrivateTheme);
+    // message list aggregation
+    const bool usePrivateAggregation = !mUseDefaultAggregationCheckBox->isChecked();
+    mAggregationComboBox->writeStorageModelConfig(QString::number(mCurrentCollection.id()), usePrivateAggregation);
+
+    MessageViewer::Viewer::DisplayFormatMessage formatMessage = MessageViewer::Viewer::Unknown;
+    if (mPreferHtmlToText->isChecked()) {
+        formatMessage = MessageViewer::Viewer::Html;
+    } else if (mPreferTextToHtml->isChecked()) {
+        formatMessage = MessageViewer::Viewer::Text;
+    } else if (mUseGlobalSettings->isChecked()) {
+        formatMessage = MessageViewer::Viewer::UseGlobalSetting;
+    } else {
+        qCDebug(KMAIL_LOG) << "No settings defined";
+    }
+    mFolderCollection->setFormatMessage(formatMessage);
+    mFolderCollection->writeConfig();
+}

src/collectionpage/collectionviewwidget.h

+/*
+   SPDX-FileCopyrightText: 2020 Laurent Montel <montel@kde.org>
+
+   SPDX-License-Identifier: GPL-2.0-or-later
+*/
+
+#ifndef COLLECTIONVIEWWIDGET_H
+#define COLLECTIONVIEWWIDGET_H
+
+#include <QWidget>
+
+class CollectionViewWidget : public QWidget
+{
+    Q_OBJECT
+public:
+    explicit CollectionViewWidget(QWidget *parent = nullptr);
+    ~CollectionViewWidget();
+};
+
+#endif // COLLECTIONVIEWWIDGET_H