Implement login/logout functionality

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

@@ -4,8 +4,8 @@ import android.os.Bundle
 import android.view.View
 import androidx.appcompat.app.AppCompatActivity
 import androidx.fragment.app.Fragment
-import androidx.fragment.app.viewModels
-import androidx.lifecycle.Observer
+import androidx.fragment.app.activityViewModels
+import androidx.lifecycle.LiveData
 import androidx.lifecycle.lifecycleScope
 import androidx.navigation.fragment.findNavController
 import by.kirich1409.viewbindingdelegate.viewBinding
@@ -19,22 +19,15 @@ import timber.log.Timber
 @AndroidEntryPoint
 class AuthenticationFragment : Fragment(R.layout.fragment_authentication) {
     private val binding by viewBinding(FragmentAuthenticationBinding::bind)
-    private val viewModel by viewModels<AuthenticationViewModel>()
+    private val viewModel by activityViewModels<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()
-        }
-    }
+    private val authStatuses: LiveData<AuthenticationState>
+        get() = viewModel.authenticationState
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         Timber.v("onCreate() called with: savedInstanceState = $savedInstanceState")
-        authStatuses.observe(this, authStatusObserver)
+        authStatuses.observe(this, ::onAuthStatusChange)
     }
 
     override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
@@ -45,9 +38,11 @@ class AuthenticationFragment : Fragment(R.layout.fragment_authentication) {
             getString(R.string.app_name)
     }
 
-    private fun navigateToRecipes() {
-        Timber.v("navigateToRecipes() called")
-        findNavController().navigate(AuthenticationFragmentDirections.actionAuthenticationFragmentToRecipesFragment())
+    private fun onAuthStatusChange(isAuthenticated: AuthenticationState) {
+        Timber.v("onAuthStatusChange() called with: isAuthenticated = $isAuthenticated")
+        if (isAuthenticated == AuthenticationState.AUTHORIZED) {
+            findNavController().popBackStack()
+        }
     }
 
     private fun onLoginClicked(): Unit = with(binding) {

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

@@ -0,0 +1,26 @@
+package gq.kirmanak.mealient.ui.auth
+
+import timber.log.Timber
+
+enum class AuthenticationState {
+    AUTHORIZED,
+    AUTH_REQUESTED,
+    UNAUTHORIZED;
+
+    companion object {
+
+        fun determineState(
+            isLoginRequested: Boolean,
+            isAuthorized: Boolean,
+        ): AuthenticationState {
+            Timber.v("determineState() called with: isLoginRequested = $isLoginRequested, isAuthorized = $isAuthorized")
+            val result = when {
+                isAuthorized -> AUTHORIZED
+                isLoginRequested -> AUTH_REQUESTED
+                else -> UNAUTHORIZED
+            }
+            Timber.v("determineState() returned: $result")
+            return result
+        }
+    }
+}

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

@@ -3,7 +3,8 @@ package gq.kirmanak.mealient.ui.auth
 import androidx.lifecycle.*
 import dagger.hilt.android.lifecycle.HiltViewModel
 import gq.kirmanak.mealient.data.auth.AuthRepo
-import gq.kirmanak.mealient.data.recipes.RecipeRepo
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.combine
 import kotlinx.coroutines.launch
 import timber.log.Timber
 import javax.inject.Inject
@@ -11,9 +12,16 @@ import javax.inject.Inject
 @HiltViewModel
 class AuthenticationViewModel @Inject constructor(
     private val authRepo: AuthRepo,
-    private val recipeRepo: RecipeRepo
 ) : ViewModel() {
 
+    private val loginRequestsFlow = MutableStateFlow(false)
+    val authenticationState: LiveData<AuthenticationState> = loginRequestsFlow.combine(
+        flow = authRepo.isAuthorizedFlow,
+        transform = AuthenticationState::determineState
+    ).asLiveData()
+    val currentAuthenticationState: AuthenticationState
+        get() = checkNotNull(authenticationState.value) { "Auth state flow mustn't be null" }
+
     fun authenticate(username: String, password: String): LiveData<Result<Unit>> {
         Timber.v("authenticate() called with: username = $username, password = $password")
         val result = MutableLiveData<Result<Unit>>()
@@ -31,16 +39,16 @@ class AuthenticationViewModel @Inject constructor(
         return result
     }
 
-    fun authenticationStatuses(): LiveData<Boolean> {
-        Timber.v("authenticationStatuses() called")
-        return authRepo.authenticationStatuses().asLiveData()
-    }
-
     fun logout() {
         Timber.v("logout() called")
         viewModelScope.launch {
+            loginRequestsFlow.emit(false)
             authRepo.logout()
-            recipeRepo.clearLocalData()
         }
     }
+
+    fun login() {
+        Timber.v("login() called")
+        viewModelScope.launch { loginRequestsFlow.emit(true) }
+    }
 }