/**
  * @RDE_HEADER@
  * IntervalModel
  * $Id$
  * $HeadURL$
  * $Author$
  * Created by Christian Fröbel, SLSE, 2017-07-19
  */

#pragma once

#include <AudioVideoManagement/ava_types.h>
#include <LtsWidgets/lts_abstract_table_model.h>
#include <boost/optional.hpp>


namespace AudioVideoManagement
{

/**
 * Model for the Timeline so it can be shown in a TabView.
 * This is a poor man's version as the timeline is displayed in a table.
 * Later it will probably be replaced by something more usable.
 * @author Christian Fröbel
 */
class IntervalModel : public LtsWidgets::LtsAbstractTableModel<AvaTimelinePart>
{
  Q_OBJECT

public:
  enum Columns
  {
    Start = 0,
    End,
    Duration,
  };

  IntervalModel();
  QVariant data(const QModelIndex &index, int role) const override;

  void reset();

  bool isEmpty() const { return m_vecData.isEmpty(); }

  void setCurrentPosition(AvaTimePoint pos, bool forceSignal = false);
  boost::optional<AvaTimePoint> currentPosition() const { return m_currentPos; }

  /**
   * If the current position is within an interval:
   * - and the position is at least 2s into the interval, return that
   * - otherwise return the previous interval (unless there is none).
   * If the current position is between two intervals return the one before
   * the current position.
   */
  const AvaTimelinePart &previousInterval() const;
  const AvaTimelinePart &nextInterval() const;

signals:
  /**
   * Emitted if the current interval changed either due to
   * setCurrentPosition() or reset().
   * There must not always be a current interval as the current position
   * can also be between two intervals.
   * @param rowIndex might be invalid if the current position is between intervals.
   */
  void currentIntervalChanged(bool hasPreviousInterval, bool hasNextInterval, const QModelIndex &rowIndex);

public slots:
  void setTimezoneHoursOffset(int timezoneHoursOffset);

private:
  QString dateTimeToStringy(const QDateTime &dt) const;
  QString msecsSinceEpochToStringy(qint64 msecs) const;

  /**
   * A HalfIndex denotes the current position within or between intervals.
   * The counting of indices is done as follows:
   *  -1   0   1   2   3   4   5   6   7
   *     -----   -----   -----   -----      # intervals 0...3
   * Examples:
   * within interval with index i => halfIndex = 2*i
   * before interval with index i => halfIndex = 2*i-1
   * after  interval with index i => halfIndex = 2*i+1
   */
  using HalfIndex = int;
  HalfIndex   intervalForPos(AvaTimePoint pos) const;

  boost::optional<AvaTimePoint>   m_currentPos;
  boost::optional<HalfIndex>      m_currentInterval;

  int m_timezoneHoursOffset = 0;
};

} // namespace AudioVideoManagement