Fix calling navigateToAuth twice and even more

Calling that method several times in a row is not supported,
Navigation library throws an Exception saying it doesn't know how
to navigate there

app/src/main/java/gq/kirmanak/mealient/ui/auth/AuthenticationFragment.kt

@@ -7,6 +7,7 @@ import android.view.ViewGroup
 import android.widget.EditText
 import androidx.fragment.app.Fragment
 import androidx.fragment.app.viewModels
+import androidx.lifecycle.Observer
 import androidx.lifecycle.lifecycleScope
 import androidx.navigation.fragment.findNavController
 import com.google.android.material.textfield.TextInputLayout
@@ -21,18 +22,20 @@ class AuthenticationFragment : Fragment() {
         get() = checkNotNull(_binding) { "Binding requested when fragment is off screen" }
     private val viewModel by viewModels<AuthenticationViewModel>()
 
+    private val authStatuses by lazy { viewModel.authenticationStatuses() }
+    private val authStatusObserver = Observer<Boolean> { onAuthStatusChange(it) }
+    private fun onAuthStatusChange(isAuthenticated: Boolean) {
+        Timber.v("onAuthStatusChange() called with: isAuthenticated = $isAuthenticated")
+        if (isAuthenticated) {
+            authStatuses.removeObserver(authStatusObserver)
+            navigateToRecipes()
+        }
+    }
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         Timber.v("onCreate() called with: savedInstanceState = $savedInstanceState")
-        listenToAuthenticationStatuses()
+        authStatuses.observe(this, authStatusObserver)
-    }
-
-    private fun listenToAuthenticationStatuses() {
-        Timber.d("listenToAuthenticationStatuses() called")
-        viewModel.authenticationStatuses().observe(this) {
-            Timber.d("listenToAuthenticationStatuses: new status = $it")
-            if (it) navigateToRecipes()
-        }
     }
 
     override fun onCreateView(

app/src/main/java/gq/kirmanak/mealient/ui/recipes/RecipesFragment.kt

@@ -6,6 +6,7 @@ import android.view.View
 import android.view.ViewGroup
 import androidx.fragment.app.Fragment
 import androidx.fragment.app.viewModels
+import androidx.lifecycle.Observer
 import androidx.lifecycle.lifecycleScope
 import androidx.navigation.fragment.findNavController
 import androidx.recyclerview.widget.LinearLayoutManager
@@ -25,7 +26,17 @@ class RecipesFragment : Fragment() {
     private val binding: FragmentRecipesBinding
         get() = checkNotNull(_binding) { "Binding requested when fragment is off screen" }
     private val viewModel by viewModels<RecipeViewModel>()
+
     private val authViewModel by viewModels<AuthenticationViewModel>()
+    private val authStatuses by lazy { authViewModel.authenticationStatuses() }
+    private val authStatusObserver = Observer<Boolean> { onAuthStatusChange(it) }
+    private fun onAuthStatusChange(isAuthenticated: Boolean) {
+        Timber.v("onAuthStatusChange() called with: isAuthenticated = $isAuthenticated")
+        if (!isAuthenticated) {
+            authStatuses.removeObserver(authStatusObserver)
+            navigateToAuthFragment()
+        }
+    }
 
     override fun onCreateView(
         inflater: LayoutInflater,
@@ -41,7 +52,7 @@ class RecipesFragment : Fragment() {
         super.onViewCreated(view, savedInstanceState)
         Timber.v("onViewCreated() called with: view = $view, savedInstanceState = $savedInstanceState")
         setupRecipeAdapter()
-        listenToAuthStatuses()
+        authStatuses.observe(this, authStatusObserver)
     }
 
     private fun navigateToRecipeInfo(recipeSummaryEntity: RecipeSummaryEntity) {
@@ -54,14 +65,6 @@ class RecipesFragment : Fragment() {
         )
     }
 
-    private fun listenToAuthStatuses() {
-        Timber.v("listenToAuthStatuses() called")
-        authViewModel.authenticationStatuses().observe(this) {
-            Timber.v("listenToAuthStatuses: new auth status = $it")
-            if (!it) navigateToAuthFragment()
-        }
-    }
-
     private fun navigateToAuthFragment() {
         Timber.v("navigateToAuthFragment() called")
         findNavController().navigate(RecipesFragmentDirections.actionRecipesFragmentToAuthenticationFragment())

app/src/main/java/gq/kirmanak/mealient/ui/recipes/info/RecipeInfoFragment.kt

@@ -6,6 +6,7 @@ import android.view.View
 import android.view.ViewGroup
 import androidx.fragment.app.Fragment
 import androidx.fragment.app.viewModels
+import androidx.lifecycle.Observer
 import androidx.navigation.fragment.findNavController
 import androidx.navigation.fragment.navArgs
 import androidx.recyclerview.widget.LinearLayoutManager
@@ -19,10 +20,20 @@ class RecipeInfoFragment : Fragment() {
     private var _binding: FragmentRecipeInfoBinding? = null
     private val binding: FragmentRecipeInfoBinding
         get() = checkNotNull(_binding) { "Binding requested when fragment is off screen" }
-    private val authViewModel by viewModels<AuthenticationViewModel>()
     private val arguments by navArgs<RecipeInfoFragmentArgs>()
     private val viewModel by viewModels<RecipeInfoViewModel>()
 
+    private val authViewModel by viewModels<AuthenticationViewModel>()
+    private val authStatuses by lazy { authViewModel.authenticationStatuses() }
+    private val authStatusObserver = Observer<Boolean> { onAuthStatusChange(it) }
+    private fun onAuthStatusChange(isAuthenticated: Boolean) {
+        Timber.v("onAuthStatusChange() called with: isAuthenticated = $isAuthenticated")
+        if (!isAuthenticated) {
+            authStatuses.removeObserver(authStatusObserver)
+            navigateToAuthFragment()
+        }
+    }
+
     override fun onCreateView(
         inflater: LayoutInflater,
         container: ViewGroup?,
@@ -36,9 +47,11 @@ class RecipeInfoFragment : Fragment() {
     override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
         super.onViewCreated(view, savedInstanceState)
         Timber.v("onViewCreated() called with: view = $view, savedInstanceState = $savedInstanceState")
-        listenToAuthStatuses()
+        authStatuses.observe(this, authStatusObserver)
+
         viewModel.loadRecipeImage(binding.image, arguments.recipeSlug)
         viewModel.loadRecipeInfo(arguments.recipeId, arguments.recipeSlug)
+
         viewModel.recipeInfo.observe(viewLifecycleOwner) {
             Timber.d("onViewCreated: full info $it")
             binding.title.text = it.recipeSummaryEntity.name
@@ -56,14 +69,6 @@ class RecipeInfoFragment : Fragment() {
         }
     }
 
-    private fun listenToAuthStatuses() {
-        Timber.v("listenToAuthStatuses() called")
-        authViewModel.authenticationStatuses().observe(this) {
-            Timber.d("listenToAuthStatuses: new auth status = $it")
-            if (!it) navigateToAuthFragment()
-        }
-    }
-
     private fun navigateToAuthFragment() {
         Timber.v("navigateToAuthFragment() called")
         findNavController().navigate(RecipeInfoFragmentDirections.actionRecipeInfoFragmentToAuthenticationFragment())