Method groupMove

app/src/API/Handlers/ProjectHandler.cpp:3604–3675

* @brief Moves a group to a new position in the project. */

 * @brief Moves a group to a new position in the project.
 */
API::CommandResponse API::Handlers::ProjectHandler::groupMove(const QString& id,
                                                              const QJsonObject& params)
{
  if (!params.contains(Keys::GroupId))
    return CommandResponse::makeError(
      id, ErrorCode::MissingParam, QStringLiteral("Missing required parameter: groupId"));

  if (!params.contains(QStringLiteral("newPosition")))
    return CommandResponse::makeError(
      id, ErrorCode::MissingParam, QStringLiteral("Missing required parameter: newPosition"));

  const int groupId     = params.value(Keys::GroupId).toInt();
  const int newPosition = params.value(QStringLiteral("newPosition")).toInt();
  const bool isDryRun   = params.value(QStringLiteral("dryRun")).toBool(false);

  auto& pm           = DataModel::ProjectModel::instance();
  const auto& groups = pm.groups();
  if (groupId < 0 || groupId >= static_cast<int>(groups.size()))
    return CommandResponse::makeError(
      id, ErrorCode::InvalidParam, QStringLiteral("Group id out of range: %1").arg(groupId));

  const int clampedNew = std::clamp(newPosition, 0, static_cast<int>(groups.size()) - 1);

  QJsonArray renumbered;
  for (const auto& g : groups) {
    const int newId = projectedAfterMove(g.groupId, groupId, clampedNew);
    if (newId == g.groupId)
      continue;

    QJsonObject row;
    row[QStringLiteral("oldGroupId")]   = g.groupId;
    row[QStringLiteral("newGroupId")]   = newId;
    row[QStringLiteral("title")]        = g.title;
    row[QStringLiteral("datasetCount")] = static_cast<int>(g.datasets.size());
    renumbered.append(row);
  }

  qint64 preEpoch = 0;
  if (!isDryRun) {
    preEpoch = captureProjectEpoch();
    pm.moveGroup(groupId, newPosition);
  }

  QJsonObject result;
  if (isDryRun)
    result[QStringLiteral("dryRun")] = true;

  result[QStringLiteral("oldPosition")] = groupId;
  result[QStringLiteral("newPosition")] = clampedNew;
  result[QStringLiteral("moved")]       = !isDryRun;
  result[QStringLiteral("renumbered")]  = renumbered;

  QString warning;
  if (isDryRun)
    warning = QStringLiteral(
      "DRY RUN: no changes were written. Re-call without dryRun:true to commit. The "
      "renumbered[] array shows the new groupId for each affected group; uniqueIds stay "
      "stable across reorders.");