Displaying information about the turn after the next one only in some cases.

4 files changed, 39 insertions, 15 deletions

diff --git a/routing/route.cpp b/routing/route.cpp
index 5467603c24..176d183ce2 100644
--- a/routing/route.cpp
+++ b/routing/route.cpp
@@ -165,14 +165,23 @@ void Route::GetCurrentTurn(double & distanceToTurnMeters, turns::TurnItem & turn
                                              m_poly.GetIterToIndex(segIdx));
 }
 
-void Route::GetNextTurn(turns::TurnItem & turn) const
+void Route::GetNextTurn(double & distanceToTurnMeters, turns::TurnItem & turn) const
 {
   auto it = GetCurrentTurn();
-  if (it != m_turns.end())
-    ++it;
-  else
-    ASSERT(it != m_turns.end(), ());
-  turn = it != m_turns.end() ? *it : turns::TurnItem();
+  auto const turnsEnd = m_turns.end();
+  ASSERT(it != turnsEnd, ());
+
+  if (it == turnsEnd || (it + 1) == turnsEnd)
+  {
+    turn = turns::TurnItem();
+    distanceToTurnMeters = 0;
+    return;
+  }
+
+  it += 1;
+  turn = *it;
+  distanceToTurnMeters = m_poly.GetDistanceM(m_poly.GetCurrentIter(),
+                                             m_poly.GetIterToIndex(it->m_index));
 }
 
 void Route::GetCurrentDirectionPoint(m2::PointD & pt) const
diff --git a/routing/route.hpp b/routing/route.hpp
index 138470d35e..5fb780c7eb 100644
--- a/routing/route.hpp
+++ b/routing/route.hpp
@@ -74,7 +74,9 @@ public:
 
   void GetCurrentTurn(double & distanceToTurnMeters, turns::TurnItem & turn) const;
   /// Returns turn after current.
-  void GetNextTurn(turns::TurnItem & turn) const;
+  /// Fills the field distanceToTurnMeters with distance for current possition to
+  /// the turn after the next turn.
+  void GetNextTurn(double & distanceToTurnMeters, turns::TurnItem & turn) const;
 
   void GetCurrentDirectionPoint(m2::PointD & pt) const;
 
diff --git a/routing/routing_session.cpp b/routing/routing_session.cpp
index aaaa362940..421ef34190 100644
--- a/routing/routing_session.cpp
+++ b/routing/routing_session.cpp
@@ -17,8 +17,16 @@ namespace
 
 int constexpr kOnRouteMissedCount = 5;
 
-// @todo(vbykoianko) The distance should depend on the current speed.
+// @TODO(vbykoianko) The distance should depend on the current speed.
 double constexpr kShowLanesDistInMeters = 500.;
+// @TODO(vbykoianko) The distance should depend on the current speed.
+// The distance before the next turn in meters when notification
+// about the turn after the next one will be shown if available.
+double constexpr kShowTheTurnAfterTheNexetM = 500.;
+// If the distance between two sequential turns is more than kMaxTurnDistM
+// the information about the second turn will be shown when the user is
+// nearing to the first one.
+double constexpr kMaxTurnDistM = 50.;
 
 // @todo(kshalnev) The distance may depend on the current speed.
 double constexpr kShowPedestrianTurnInMeters = 5.;
@@ -200,15 +208,20 @@ void RoutingSession::GetRouteFollowingInfo(FollowingInfo & info) const
   {
     formatDistFn(m_route.GetCurrentDistanceToEndMeters(), info.m_distToTarget, info.m_targetUnitsSuffix);
 
-    double distanceToTurnMeters = 0.;
+    double distanceToTurnMeters = 0., distanceToNextTurnMeters = 0.;
     turns::TurnItem turn;
     turns::TurnItem nextTurn;
     m_route.GetCurrentTurn(distanceToTurnMeters, turn);
-    m_route.GetNextTurn(nextTurn);
+    m_route.GetNextTurn(distanceToNextTurnMeters, nextTurn);
+    double const distBetweenTurnsM = distanceToNextTurnMeters - distanceToTurnMeters;
+    ASSERT_LESS_OR_EQUAL(0, distBetweenTurnsM, ());
 
     formatDistFn(distanceToTurnMeters, info.m_distToTurn, info.m_turnUnitsSuffix);
     info.m_turn = turn.m_turn;
-    info.m_nextTurn = nextTurn.m_turn;
+    if (distanceToTurnMeters < kShowTheTurnAfterTheNexetM && distBetweenTurnsM < kMaxTurnDistM)
+      info.m_nextTurn = nextTurn.m_turn;
+    else
+      info.m_nextTurn = routing::turns::TurnDirection::NoTurn;
     info.m_exitNum = turn.m_exitNum;
     info.m_time = m_route.GetCurrentTimeToEndSec();
     info.m_sourceName = turn.m_sourceName;
diff --git a/routing/routing_tests/route_tests.cpp b/routing/routing_tests/route_tests.cpp
index 317fb085ff..20763bf9d0 100644
--- a/routing/routing_tests/route_tests.cpp
+++ b/routing/routing_tests/route_tests.cpp
@@ -86,24 +86,24 @@ UNIT_TEST(NextTurnTest)
   vector<turns::TurnItem> turns(kTestTurns);
   route.SetTurnInstructions(turns);
 
-  double distance;
+  double distance, nextDistance;
   turns::TurnItem turn;
   turns::TurnItem nextTurn;
 
   route.GetCurrentTurn(distance, turn);
-  route.GetNextTurn(nextTurn);
+  route.GetNextTurn(nextDistance, nextTurn);
   TEST_EQUAL(turn, kTestTurns[0], ());
   TEST_EQUAL(nextTurn, kTestTurns[1], ());
 
   route.MoveIterator(GetGps(0.5, 1));
   route.GetCurrentTurn(distance, turn);
-  route.GetNextTurn(nextTurn);
+  route.GetNextTurn(nextDistance, nextTurn);
   TEST_EQUAL(turn, kTestTurns[1], ());
   TEST_EQUAL(nextTurn, kTestTurns[2], ());
 
   route.MoveIterator(GetGps(1, 1.5));
   route.GetCurrentTurn(distance, turn);
-  route.GetNextTurn(nextTurn);
+  route.GetNextTurn(nextDistance, nextTurn);
   TEST_EQUAL(turn, kTestTurns[2], ());
   TEST_EQUAL(nextTurn, turns::TurnItem(), ());
 }