[Client] Show latency in status bar and server tab indicator (#7154)

* [Client] Show live connection latency in the status bar

Add a permanent status-bar label fed by ConnectionController's
pingStatsUpdated: shows the latest round-trip time, hides while
disconnected or without samples, and carries a tooltip with
Last/Median/95th percentile/Maximum over the rolling sample window
(mirrored into the accessible description). The server tab gets the
same stats as its tooltip.

Took 2 minutes

Took 2 minutes

Took 1 minute

Took 48 seconds

Took 25 seconds

Took 4 minutes

* [Client] Graph connection latency history in the status bar

Add LatencyGraphWidget, a size-agnostic bar sparkline over the rolling
sample window: heights scale to the window's own range while colors map
onto an absolute quality ramp, so a steady good ping stays green. Embed
it in the new LatencyStatusWidget together with the textual ping
readout and feed both through ConnectionController's forwarded signals;
the whole area hides while disconnected or without samples.

Took 9 minutes

Took 14 seconds

* [Client] Show latency details when clicking the ping display

Clicking the status bar ping area opens a popup with a larger instance
of the latency graph plus the numeric statistics, selectable and
mirrored into the accessible name. Qt::Popup closes it on any outside
click; contents refresh live while open.


Took 33 seconds

* Fixup from core commit

Took 6 minutes

Took 5 seconds

Took 5 minutes

* Lint.

Took 12 minutes

* Consolidate.

Took 6 minutes

---------

Co-authored-by: Lukas Brübach <Bruebach.Lukas@bdosecurity.de>

cockatrice/src/client/latency_graph_widget.cpp

@@ -0,0 +1,51 @@
+/**
+ * @file latency_graph_widget.cpp
+ * @ingroup Client
+ */
+
+#include "latency_graph_widget.h"
+
+#include <QPainter>
+
+LatencyGraphWidget::LatencyGraphWidget(QWidget *parent) : QWidget(parent)
+{
+}
+
+void LatencyGraphWidget::setSamples(const QList<int> &samplesMs)
+{
+    samples = samplesMs;
+    update();
+}
+
+void LatencyGraphWidget::paintEvent(QPaintEvent * /* event */)
+{
+    if (samples.isEmpty()) {
+        return;
+    }
+
+    QPainter painter(this);
+
+    // Heights are relative to the window's own worst sample (floored at
+    // MinScaleMs) so the shape of the variance stays readable even when every
+    // value is small.
+    qint64 heightScaleMs = MinScaleMs;
+    for (int sample : samples) {
+        heightScaleMs = qMax(heightScaleMs, static_cast<qint64>(sample));
+    }
+
+    const qreal widthPerBar = static_cast<qreal>(width()) / samples.size();
+    for (int i = 0; i < samples.size(); ++i) {
+        const qreal heightRatio = qBound(0.0, static_cast<double>(samples.at(i)) / heightScaleMs, 1.0);
+        const qreal barHeight = heightRatio * height();
+
+        // Colors follow an absolute quality ramp: a steady good ping stays
+        // green no matter how uniform the window is.
+        const qreal colorRatio = qBound(0.0, static_cast<double>(samples.at(i)) / ColorScaleMs, 1.0);
+        QColor color;
+        color.setHsv(qRound(120.0 * (1.0 - colorRatio)), 255, 255);
+
+        const QRectF bar(static_cast<qreal>(i) * widthPerBar + 1.0, static_cast<qreal>(height()) - barHeight,
+                         qMax(1.0, widthPerBar - 2.0), barHeight);
+        painter.fillRect(bar, color);
+    }
+}

cockatrice/src/client/latency_graph_widget.h

@@ -0,0 +1,43 @@
+/**
+ * @file latency_graph_widget.h
+ * @ingroup Client
+ */
+
+#ifndef LATENCY_GRAPH_WIDGET_H
+#define LATENCY_GRAPH_WIDGET_H
+
+#include <QList>
+#include <QWidget>
+
+/**
+ * @brief Bar graph of recent network round-trip samples.
+ *
+ * Draws one bar per sample, oldest on the left. Bar height is relative to the
+ * window's own scale so the shape of the variance stays readable, while bar
+ * color maps each sample onto an absolute quality ramp (green at rest through
+ * red at ColorScaleMs) so a steady good ping never looks alarming. Size
+ * agnostic: the status bar embeds a small instance while the latency detail
+ * popup shows a large one.
+ */
+class LatencyGraphWidget : public QWidget
+{
+    Q_OBJECT
+public:
+    explicit LatencyGraphWidget(QWidget *parent = nullptr);
+
+    /// Sample in milliseconds that maps to a fully red bar.
+    static constexpr qint64 ColorScaleMs = 500;
+
+    void setSamples(const QList<int> &samplesMs);
+
+protected:
+    void paintEvent(QPaintEvent *event) override;
+
+private:
+    /// Floor of the vertical scale in milliseconds. Keeps small windows readable.
+    static constexpr qint64 MinScaleMs = 100;
+
+    QList<int> samples;
+};
+
+#endif

cockatrice/src/client/latency_status_widget.cpp

@@ -0,0 +1,111 @@
+/**
+ * @file latency_status_widget.cpp
+ * @ingroup Client
+ */
+
+#include "latency_status_widget.h"
+
+#include "latency_graph_widget.h"
+
+#include <QEvent>
+#include <QHBoxLayout>
+#include <QLabel>
+#include <QVBoxLayout>
+
+LatencyStatusWidget::LatencyStatusWidget(QWidget *parent) : QWidget(parent)
+{
+    pingLabel = new QLabel(this);
+    pingLabel->setAccessibleName(tr("Ping"));
+
+    latencyGraph = new LatencyGraphWidget(this);
+    latencyGraph->setFixedSize(90, 14);
+
+    auto *layout = new QHBoxLayout(this);
+    layout->setContentsMargins(0, 0, 0, 0);
+    layout->setSpacing(4);
+    layout->addWidget(latencyGraph);
+    layout->addWidget(pingLabel);
+
+    // Clicking anywhere in the area opens the detail view.
+    for (QObject *child : QList<QObject *>{pingLabel, latencyGraph}) {
+        child->installEventFilter(this);
+    }
+    setCursor(Qt::PointingHandCursor);
+
+    hide();
+}
+
+void LatencyStatusWidget::updateData(const LatencyTracker::Stats &stats, const QList<int> &samplesMs)
+{
+    latestSamples = samplesMs;
+    latencyGraph->setSamples(samplesMs);
+    if (popup && popup->isVisible() && detailGraph) {
+        detailGraph->setSamples(samplesMs);
+    }
+
+    if (stats.sampleCount == 0) {
+        hide();
+        return;
+    }
+
+    const QString statsStr = statsText(stats);
+
+    pingLabel->setText(tr("Ping: %1 ms").arg(stats.lastMs));
+    pingLabel->setToolTip(statsStr);
+    pingLabel->setAccessibleDescription(statsStr);
+    if (popup && popup->isVisible() && detailLabel) {
+        detailLabel->setText(statsStr);
+    }
+    show();
+}
+
+bool LatencyStatusWidget::eventFilter(QObject *watched, QEvent *event)
+{
+    if ((watched == pingLabel || watched == latencyGraph) && event->type() == QEvent::MouseButtonPress) {
+        togglePopup();
+        return true;
+    }
+    return QWidget::eventFilter(watched, event);
+}
+
+void LatencyStatusWidget::togglePopup()
+{
+    if (!popup) {
+        popup = new QWidget(this, Qt::Popup | Qt::FramelessWindowHint);
+        auto *layout = new QVBoxLayout(popup);
+        layout->setContentsMargins(8, 8, 8, 8);
+
+        detailLabel = new QLabel(popup);
+        detailLabel->setAccessibleName(tr("Connection latency details"));
+        detailLabel->setTextInteractionFlags(Qt::TextSelectableByMouse);
+
+        detailGraph = new LatencyGraphWidget(popup);
+        detailGraph->setFixedSize(280, 80);
+
+        layout->addWidget(detailLabel, 0, Qt::AlignLeft);
+        layout->addWidget(detailGraph, 0, Qt::AlignHCenter);
+    }
+
+    if (popup->isVisible()) {
+        popup->hide();
+        return;
+    }
+
+    // Qt::Popup closes itself on any outside click, so just position and show.
+    if (latestSamples.isEmpty()) {
+        return;
+    }
+    detailGraph->setSamples(latestSamples);
+    detailLabel->setText(pingLabel->toolTip());
+    popup->adjustSize();
+    const QPoint anchor = mapToGlobal(QPoint(width() / 2, 0));
+    popup->move(anchor.x() - popup->width() / 2, anchor.y() - popup->height() - 6);
+    popup->show();
+}
+
+QString LatencyStatusWidget::statsText(const LatencyTracker::Stats &stats) const
+{
+    return tr("Connection quality over the last %n sample(s):", "", stats.sampleCount) + "\n" +
+           tr("Last: %1 ms").arg(stats.lastMs) + "\n" + tr("Median: %1 ms").arg(stats.medianMs) + "\n" +
+           tr("95th percentile: %1 ms").arg(stats.p95Ms) + "\n" + tr("Maximum: %1 ms").arg(stats.maxMs);
+}

cockatrice/src/client/latency_status_widget.h

@@ -0,0 +1,50 @@
+/**
+ * @file latency_status_widget.h
+ * @ingroup Client
+ */
+
+#ifndef LATENCY_STATUS_WIDGET_H
+#define LATENCY_STATUS_WIDGET_H
+
+#include <QList>
+#include <QWidget>
+#include <libcockatrice/network/client/abstract/latency_tracker.h>
+
+class QLabel;
+class LatencyGraphWidget;
+
+/**
+ * @brief Status bar presentation of server round-trip health.
+ *
+ * Combines the textual "Ping" readout with a small LatencyGraphWidget
+ * sparkline of the rolling sample window. Clicking anywhere in the area opens
+ * a popup with a larger graph and the numeric statistics. It closes on any
+ * outside click. Stays hidden while disconnected or before any samples exist.
+ * Owns all latency display state so MainWindow only needs to forward one
+ * signal here.
+ */
+class LatencyStatusWidget : public QWidget
+{
+    Q_OBJECT
+public:
+    explicit LatencyStatusWidget(QWidget *parent = nullptr);
+
+public slots:
+    void updateData(const LatencyTracker::Stats &stats, const QList<int> &samplesMs);
+
+protected:
+    bool eventFilter(QObject *watched, QEvent *event) override;
+
+private:
+    void togglePopup();
+    QString statsText(const LatencyTracker::Stats &stats) const;
+
+    QLabel *pingLabel = nullptr;
+    LatencyGraphWidget *latencyGraph = nullptr;
+    QWidget *popup = nullptr;
+    LatencyGraphWidget *detailGraph = nullptr;
+    QLabel *detailLabel = nullptr;
+    QList<int> latestSamples;
+};
+
+#endif