NAVAND-1152: fix alternative route geometry index calculation for not started alternatives

Author: dzinad

changelog/unreleased/bugfixes/6935.md

@@ -0,0 +1 @@
+- Fixed an issue where alternative routes refresh might have finished with response code 422.

libnavigation-core/src/main/java/com/mapbox/navigation/core/routealternatives/AlternativeRouteProgressDataProvider.kt

@@ -24,8 +24,13 @@ internal object AlternativeRouteProgressDataProvider {
             legIndex = primaryRouteProgressData.legIndex - legIndexDiff
             val routeGeometryIndexDiff =
                 primaryFork.geometryIndexInRoute - alternativeFork.geometryIndexInRoute
-            routeGeometryIndex =
+            val alternativeStarted =
+                primaryRouteProgressData.routeGeometryIndex >= routeGeometryIndexDiff
+            routeGeometryIndex = if (alternativeStarted) {
                 primaryRouteProgressData.routeGeometryIndex - routeGeometryIndexDiff
+            } else {
+                0
+            }
             legGeometryIndex = routeGeometryIndex -
                 prevLegsGeometryIndicesCount(alternativeMetadata.navigationRoute, legIndex)
         } else {

libnavigation-core/src/test/java/com/mapbox/navigation/core/routealternatives/AlternativeRouteProgressDataProviderTest.kt

@@ -107,6 +107,31 @@ class AlternativeRouteProgressDataProviderTest {
         assertEquals(expected, actual)
     }
 
+    @Test
+    fun `before fork, alternative starts after the primary route ahead of current position`() =
+        coroutineRule.runBlockingTest {
+            val primaryRouteProgressData = RouteProgressData(0, 3, 3)
+            val alternativeMetadata = alternativeRouteMetadata(
+                primaryForkLegIndex = 0,
+                primaryForkRouteGeometryIndex = 100,
+                primaryForkLegGeometryIndex = 100,
+                alternativeForkLegIndex = 0,
+                alternativeForkRouteGeometryIndex = 80,
+                alternativeForkLegGeometryIndex = 80,
+                listOf(
+                    listOf(List(10) { mockk() }, List(7) { mockk() }, List(15) { mockk() }),
+                )
+            )
+            val expected = RouteProgressData(0, 0, 0)
+
+            val actual = AlternativeRouteProgressDataProvider.getRouteProgressData(
+                primaryRouteProgressData,
+                alternativeMetadata
+            )
+
+            assertEquals(expected, actual)
+        }
+
     @Test
     fun `before fork, alternative starts together with the primary route`() = coroutineRule.runBlockingTest {
         val primaryRouteProgressData = RouteProgressData(4, 200, 30)