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#include <QtWidgets>

#include "characterwidget.h"
#include "mainwindow.h"


Q_DECLARE_METATYPE(QFontComboBox::FontFilter)

MainWindow::MainWindow()
{
    QMenu *fileMenu = menuBar()->addMenu(tr("File"));
    fileMenu->addAction(tr("Quit"), this, &QWidget::close);
    QMenu *helpMenu = menuBar()->addMenu(tr("&Help"));
    helpMenu->addAction(tr("Show Font Info"), this, &MainWindow::showInfo);
    helpMenu->addAction(tr("About &Qt"), qApp, &QApplication::aboutQt);

    QWidget *centralWidget = new QWidget;

    QLabel *filterLabel = new QLabel(tr("Filter:"));
    filterCombo = new QComboBox;
    filterCombo->addItem(tr("All"), QVariant::fromValue(QFontComboBox::AllFonts));
    filterCombo->addItem(tr("Scalable"), QVariant::fromValue(QFontComboBox::ScalableFonts));
    filterCombo->addItem(tr("Monospaced"), QVariant::fromValue(QFontComboBox::MonospacedFonts));
    filterCombo->addItem(tr("Proportional"), QVariant::fromValue(QFontComboBox::ProportionalFonts));
    filterCombo->setCurrentIndex(0);
    connect(filterCombo, QOverload<int>::of(&QComboBox::currentIndexChanged),
            this, &MainWindow::filterChanged);

    QLabel *fontLabel = new QLabel(tr("Font:"));
    fontCombo = new QFontComboBox;
    QLabel *sizeLabel = new QLabel(tr("Size:"));
    sizeCombo = new QComboBox;
    QLabel *styleLabel = new QLabel(tr("Style:"));
    styleCombo = new QComboBox;
    QLabel *fontMergingLabel = new QLabel(tr("Automatic Font Merging:"));
    fontMerging = new QCheckBox;
    fontMerging->setChecked(true);

    scrollArea = new QScrollArea;
    characterWidget = new CharacterWidget;
    scrollArea->setWidget(characterWidget);

    findStyles(fontCombo->currentFont());
    findSizes(fontCombo->currentFont());

    lineEdit = new QLineEdit;
    lineEdit->setClearButtonEnabled(true);
#ifndef QT_NO_CLIPBOARD
    QPushButton *clipboardButton = new QPushButton(tr("&To clipboard"));

#endif

    connect(fontCombo, &QFontComboBox::currentFontChanged,
            this, &MainWindow::findStyles);
    connect(fontCombo, &QFontComboBox::currentFontChanged,
            this, &MainWindow::findSizes);
    connect(fontCombo, &QFontComboBox::currentFontChanged,
            characterWidget, &CharacterWidget::updateFont);
    connect(sizeCombo, QOverload<const QString &>::of(&QComboBox::currentIndexChanged),
            characterWidget, &CharacterWidget::updateSize);
    connect(styleCombo, QOverload<const QString &>::of(&QComboBox::currentIndexChanged),
            characterWidget, &CharacterWidget::updateStyle);
    connect(characterWidget, &CharacterWidget::characterSelected,
            this, &MainWindow::insertCharacter);

#ifndef QT_NO_CLIPBOARD
    connect(clipboardButton, &QAbstractButton::clicked, this, &MainWindow::updateClipboard);
#endif
    connect(fontMerging, &QAbstractButton::toggled, characterWidget, &CharacterWidget::updateFontMerging);

    QHBoxLayout *controlsLayout = new QHBoxLayout;
    controlsLayout->addWidget(filterLabel);
    controlsLayout->addWidget(filterCombo, 1);
    controlsLayout->addWidget(fontLabel);
    controlsLayout->addWidget(fontCombo, 1);
    controlsLayout->addWidget(sizeLabel);
    controlsLayout->addWidget(sizeCombo, 1);
    controlsLayout->addWidget(styleLabel);
    controlsLayout->addWidget(styleCombo, 1);
    controlsLayout->addWidget(fontMergingLabel);
    controlsLayout->addWidget(fontMerging, 1);
    controlsLayout->addStretch(1);

    QHBoxLayout *lineLayout = new QHBoxLayout;
    lineLayout->addWidget(lineEdit, 1);
    lineLayout->addSpacing(12);
#ifndef QT_NO_CLIPBOARD
    lineLayout->addWidget(clipboardButton);
#endif

    QVBoxLayout *centralLayout = new QVBoxLayout;
    centralLayout->addLayout(controlsLayout);
    centralLayout->addWidget(scrollArea, 1);
    centralLayout->addSpacing(4);
    centralLayout->addLayout(lineLayout);
    centralWidget->setLayout(centralLayout);

    setCentralWidget(centralWidget);
    setWindowTitle(tr("Character Map"));
}

void MainWindow::findStyles(const QFont &font)
{
    QFontDatabase fontDatabase;
    QString currentItem = styleCombo->currentText();
    styleCombo->clear();

    QString style;
    foreach (style, fontDatabase.styles(font.family()))
        styleCombo->addItem(style);

    int styleIndex = styleCombo->findText(currentItem);

    if (styleIndex == -1)
        styleCombo->setCurrentIndex(0);
    else
        styleCombo->setCurrentIndex(styleIndex);
}

void MainWindow::filterChanged(int f)
{
    const QFontComboBox::FontFilter filter =
        filterCombo->itemData(f).value<QFontComboBox::FontFilter>();
    fontCombo->setFontFilters(filter);
    statusBar()->showMessage(tr("%n font(s) found", 0, fontCombo->count()));
}

void MainWindow::findSizes(const QFont &font)
{
    QFontDatabase fontDatabase;
    QString currentSize = sizeCombo->currentText();

    {
        const QSignalBlocker blocker(sizeCombo);
        // sizeCombo signals are now blocked until end of scope
        sizeCombo->clear();

        int size;
        if (fontDatabase.isSmoothlyScalable(font.family(), fontDatabase.styleString(font))) {
            foreach (size, QFontDatabase::standardSizes()) {
                sizeCombo->addItem(QVariant(size).toString());
                sizeCombo->setEditable(true);
            }

        } else {
            foreach (size, fontDatabase.smoothSizes(font.family(), fontDatabase.styleString(font))) {
                sizeCombo->addItem(QVariant(size).toString());
                sizeCombo->setEditable(false);
            }
        }
    }

    int sizeIndex = sizeCombo->findText(currentSize);

    if(sizeIndex == -1)
        sizeCombo->setCurrentIndex(qMax(0, sizeCombo->count() / 3));
    else
        sizeCombo->setCurrentIndex(sizeIndex);
}

void MainWindow::insertCharacter(const QString &character)
{
    lineEdit->insert(character);
}

#ifndef QT_NO_CLIPBOARD
void MainWindow::updateClipboard()
{
    QGuiApplication::clipboard()->setText(lineEdit->text(), QClipboard::Clipboard);
    QGuiApplication::clipboard()->setText(lineEdit->text(), QClipboard::Selection);
}
#endif

class FontInfoDialog : public QDialog
{
public:
    explicit FontInfoDialog(QWidget *parent = nullptr);

private:
    QString text() const;
};

FontInfoDialog::FontInfoDialog(QWidget *parent) : QDialog(parent)
{
    setWindowFlags(windowFlags() & ~Qt::WindowContextHelpButtonHint);
    QVBoxLayout *mainLayout = new QVBoxLayout(this);
    QPlainTextEdit *textEdit = new QPlainTextEdit(text(), this);
    textEdit->setReadOnly(true);
    textEdit->setFont(QFontDatabase::systemFont(QFontDatabase::FixedFont));
    mainLayout->addWidget(textEdit);
    QDialogButtonBox *buttonBox = new QDialogButtonBox(QDialogButtonBox::Close, this);
    connect(buttonBox, &QDialogButtonBox::rejected, this, &QDialog::reject);
    mainLayout->addWidget(buttonBox);
}

QString FontInfoDialog::text() const
{
    QString text;
    QTextStream str(&text);
    const QFont defaultFont = QFontDatabase::systemFont(QFontDatabase::GeneralFont);
    const QFont fixedFont = QFontDatabase::systemFont(QFontDatabase::FixedFont);
    const QFont titleFont = QFontDatabase::systemFont(QFontDatabase::TitleFont);
    const QFont smallestReadableFont = QFontDatabase::systemFont(QFontDatabase::SmallestReadableFont);

    str << "Qt " << QT_VERSION_STR << " on " << QGuiApplication::platformName()
        << ", " << logicalDpiX() << "DPI";
    if (!qFuzzyCompare(devicePixelRatioF(), qreal(1)))
        str  << ", device pixel ratio: " << devicePixelRatioF();
    str << "\n\nDefault font : " << defaultFont.family() << ", " << defaultFont.pointSizeF() << "pt\n"
        << "Fixed font   : " << fixedFont.family() << ", " << fixedFont.pointSizeF() << "pt\n"
        << "Title font   : " << titleFont.family() << ", " << titleFont.pointSizeF() << "pt\n"
        << "Smallest font: " << smallestReadableFont.family() << ", " << smallestReadableFont.pointSizeF() << "pt\n";

    return text;
}

void MainWindow::showInfo()
{
    const QRect screenGeometry = QApplication::desktop()->screenGeometry(this);
    FontInfoDialog *dialog = new FontInfoDialog(this);
    dialog->setWindowTitle(tr("Fonts"));
    dialog->setAttribute(Qt::WA_DeleteOnClose);
    dialog->resize(screenGeometry.width() / 4, screenGeometry.height() / 4);
    dialog->show();
}