From 3b539476ae59c3d24d6ae95f62a96e14430a997d Mon Sep 17 00:00:00 2001
From: Vladimir Byko-Ianko <v.bykoianko@corp.mail.ru>
Date: Thu, 25 Jul 2019 15:09:18 +0300
Subject: [PATCH] [routing] Using PositionAccumulator to calculate better an
 end user direction.

---
 map/routing_manager.cpp     |  3 +++
 routing/routing_session.cpp | 10 +++-------
 routing/routing_session.hpp | 13 ++++++++-----
 3 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/map/routing_manager.cpp b/map/routing_manager.cpp
index 3c3a4dc226..1c605d532d 100644
--- a/map/routing_manager.cpp
+++ b/map/routing_manager.cpp
@@ -1015,6 +1015,7 @@ void RoutingManager::BuildRoute(uint32_t timeoutSec)
   m_drapeEngine.SafeCall(&df::DrapeEngine::SetModelViewRect, rect, true /* applyRotation */,
                          -1 /* zoom */, true /* isAnim */, true /* useVisibleViewport */);
 
+  m_routingSession.ClearPositionAccumulator();
   m_routingSession.SetUserCurrentPosition(routePoints.front().m_position);
 
   vector<m2::PointD> points;
@@ -1027,6 +1028,8 @@ void RoutingManager::BuildRoute(uint32_t timeoutSec)
 
 void RoutingManager::SetUserCurrentPosition(m2::PointD const & position)
 {
+  // @TODO(bykoianko) PositionAccumulator should be filled even if there's no route.
+  // That means IsRoutingActive() returns false.
   if (IsRoutingActive())
     m_routingSession.SetUserCurrentPosition(position);
 
diff --git a/routing/routing_session.cpp b/routing/routing_session.cpp
index e8269e605d..e5f355bab7 100644
--- a/routing/routing_session.cpp
+++ b/routing/routing_session.cpp
@@ -111,7 +111,7 @@ void RoutingSession::RebuildRoute(m2::PointD const & startPoint,
 
   // Use old-style callback construction, because lambda constructs buggy function on Android
   // (callback param isn't captured by value).
-  m_router->CalculateRoute(m_checkpoints, m_currentDirection, adjustToPrevRoute,
+  m_router->CalculateRoute(m_checkpoints, m_positionAccumulator.GetDirection(), adjustToPrevRoute,
                            DoReadyCallback(*this, readyCallback),
                            needMoreMapsCallback, removeRouteCallback, m_progressCallback, timeoutSec);
 }
@@ -342,9 +342,6 @@ SessionState RoutingSession::OnLocationPositionChanged(GpsInfo const & info)
     }
   }
 
-  if (m_userCurrentPositionValid && m_userFormerPositionValid)
-    m_currentDirection = m_userCurrentPosition - m_userFormerPosition;
-
   return m_state;
 }
 
@@ -610,12 +607,11 @@ void RoutingSession::SetChangeSessionStateCallback(
 void RoutingSession::SetUserCurrentPosition(m2::PointD const & position)
 {
   CHECK_THREAD_CHECKER(m_threadChecker, ());
-  // All methods which read/write m_userCurrentPosition*, m_userFormerPosition*  work in RoutingManager thread
-  m_userFormerPosition = m_userCurrentPosition;
-  m_userFormerPositionValid = m_userCurrentPositionValid;
 
   m_userCurrentPosition = position;
   m_userCurrentPositionValid = true;
+
+  m_positionAccumulator.PushNextPoint(position);
 }
 
 void RoutingSession::EnableTurnNotifications(bool enable)
diff --git a/routing/routing_session.hpp b/routing/routing_session.hpp
index 03036b8af9..cb4fcfafea 100644
--- a/routing/routing_session.hpp
+++ b/routing/routing_session.hpp
@@ -1,6 +1,7 @@
 #pragma once
 
 #include "routing/async_router.hpp"
+#include "routing/position_accumulator.hpp"
 #include "routing/route.hpp"
 #include "routing/router.hpp"
 #include "routing/routing_callbacks.hpp"
@@ -105,6 +106,10 @@ public:
 
   void SetUserCurrentPosition(m2::PointD const & position);
 
+  void ClearPositionAccumulator() { m_positionAccumulator.Clear(); }
+
+  void ActivateAdditionalFeatures() {}
+
   /// Disable following mode on GPS updates. Following mode is disabled only for the current route.
   /// If a route is rebuilt you must call DisableFollowMode again.
   /// Returns true if following was disabled, false if a route is not ready for the following yet.
@@ -188,17 +193,13 @@ private:
   bool m_isFollowing;
   Checkpoints m_checkpoints;
 
-
   /// Current position metrics to check for RouteNeedRebuild state.
   double m_lastDistance = 0.0;
   int m_moveAwayCounter = 0;
   m2::PointD m_lastGoodPosition;
-  // |m_currentDirection| is a vector from the position before last good position to last good position.
-  m2::PointD m_currentDirection;
+
   m2::PointD m_userCurrentPosition;
-  m2::PointD m_userFormerPosition;
   bool m_userCurrentPositionValid = false;
-  bool m_userFormerPositionValid = false;
 
   // Sound turn notification parameters.
   turns::sound::NotificationManager m_turnNotificationsMgr;
@@ -206,6 +207,8 @@ private:
   SpeedCameraManager m_speedCameraManager;
   RoutingSettings m_routingSettings;
 
+  PositionAccumulator m_positionAccumulator;
+
   ReadyCallback m_buildReadyCallback;
   ReadyCallback m_rebuildReadyCallback;
   NeedMoreMapsCallback m_needMoreMapsCallback;