Method loadChartSeries

app/src/Sessions/ReportData.cpp:563–633

* @brief Loads downsampled numeric time-series for every parameter. */

 * @brief Loads downsampled numeric time-series for every parameter.
 */
std::vector<Sessions::DatasetSeries> Sessions::loadChartSeries(QSqlDatabase& db,
                                                               int sessionId,
                                                               int maxSamples,
                                                               const QSet<int>& selectedUniqueIds)
{
  std::vector<DatasetSeries> out;
  if (!db.isOpen() || sessionId < 0 || maxSamples < 2)
    return out;

  Q_ASSERT(maxSamples >= 2);
  Q_ASSERT(db.isOpen());

  const auto metas = loadChartParameters(db, sessionId);
  if (metas.empty())
    return out;

  const auto [originNs, _] = loadSessionTimeSpan(db, sessionId);
  const auto counts        = loadSampleCounts(db, sessionId);

  DSP::AxisData x(16);
  DSP::AxisData y(16);

  for (const auto& m : metas) {
    if (!selectedUniqueIds.isEmpty() && !selectedUniqueIds.contains(m.uid))
      continue;

    const auto it      = counts.find(m.uid);
    const qint64 total = (it != counts.end()) ? it->second : 0;
    if (total < 2)
      continue;

    QSqlQuery rows(db);
    rows.setForwardOnly(true);
    rows.prepare("SELECT timestamp_ns, final_numeric_value FROM readings "
                 "WHERE session_id = ? AND unique_id = ? AND is_numeric = 1 "
                 "ORDER BY timestamp_ns, reading_id");
    rows.bindValue(0, sessionId);
    rows.bindValue(1, m.uid);
    if (!rows.exec()) {
      qWarning() << "[Sessions::ReportData] readings query failed for uid" << m.uid << ":"
                 << rows.lastError().text();
      continue;
    }

    double globalMin = 0.0;
    double globalMax = 0.0;
    const auto count = readAxisData(rows, originNs, total, x, y, globalMin, globalMax);
    if (count < 2)
      continue;

    DatasetSeries series;
    series.uniqueId     = m.uid;
    series.totalSamples = total;
    series.sourceTitle  = m.sourceTitle;
    series.group        = m.group;
    series.title        = m.title;
    series.units        = m.units;
    series.minValue     = globalMin;