Extract login and credentials verification logic into usecases

app/app/src/main/java/ing/bikeshedengineer/debtpirate/app/host/MainActivity.kt

@@ -8,8 +8,8 @@ import androidx.navigation.compose.NavHost
 import androidx.navigation.compose.composable
 import androidx.navigation.compose.rememberNavController
 import dagger.hilt.android.AndroidEntryPoint
-import ing.bikeshedengineer.debtpirate.presentation.theme.DebtPirateTheme
+import ing.bikeshedengineer.debtpirate.theme.DebtPirateTheme
-import ing.bikeshedengineer.debtpirate.presentation.ui.auth.AuthScreen
+import ing.bikeshedengineer.debtpirate.auth.presentation.AuthScreen
 import kotlinx.serialization.Serializable
 
 @Serializable
@@ -26,9 +26,7 @@ class MainActivity : ComponentActivity() {
 
             DebtPirateTheme {
                 NavHost(navController = navController, startDestination = AuthRoute) {
-                    composable<AuthRoute> {
+                    composable<AuthRoute>() { AuthScreen() }
-                        AuthScreen()
-                    }
                 }
             }
         }

app/app/src/main/java/ing/bikeshedengineer/debtpirate/auth/data/remote/endpoint/AuthEndpoint.kt

@@ -1,8 +1,8 @@
-package ing.bikeshedengineer.debtpirate.data.remote.endpoint
+package ing.bikeshedengineer.debtpirate.auth.data.remote.endpoint
 
-import ing.bikeshedengineer.debtpirate.data.remote.model.ApiResponse
+import ing.bikeshedengineer.debtpirate.data.remote.ApiResponse
-import ing.bikeshedengineer.debtpirate.data.remote.model.auth.AuthLoginRequest
+import ing.bikeshedengineer.debtpirate.auth.data.remote.model.AuthLoginRequest
-import ing.bikeshedengineer.debtpirate.data.remote.model.auth.AuthLoginResponse
+import ing.bikeshedengineer.debtpirate.auth.data.remote.model.AuthLoginResponse
 import retrofit2.Response
 import retrofit2.http.Body
 import retrofit2.http.POST

app/app/src/main/java/ing/bikeshedengineer/debtpirate/auth/data/remote/model/AuthLoginRequest.kt

@@ -1,3 +1,3 @@
-package ing.bikeshedengineer.debtpirate.data.remote.model.auth
+package ing.bikeshedengineer.debtpirate.auth.data.remote.model
 
 data class AuthLoginRequest(val username: String, val password: String)

app/app/src/main/java/ing/bikeshedengineer/debtpirate/auth/data/remote/model/AuthLoginResponse.kt

@@ -1,4 +1,4 @@
-package ing.bikeshedengineer.debtpirate.data.remote.model.auth
+package ing.bikeshedengineer.debtpirate.auth.data.remote.model
 
 data class AuthLoginResponse(
     val userId: Int,

app/app/src/main/java/ing/bikeshedengineer/debtpirate/auth/data/remote/repository/AuthRepository.kt

@@ -0,0 +1,8 @@
+package ing.bikeshedengineer.debtpirate.auth.data.remote.repository
+
+import ing.bikeshedengineer.debtpirate.auth.data.remote.model.AuthLoginRequest
+import ing.bikeshedengineer.debtpirate.auth.data.remote.model.AuthLoginResponse
+
+interface AuthRepository {
+    suspend fun submitLoginRequest(credentials: AuthLoginRequest): AuthLoginResponse
+}

app/app/src/main/java/ing/bikeshedengineer/debtpirate/auth/di/AuthDiModule.kt

@@ -0,0 +1,33 @@
+package ing.bikeshedengineer.debtpirate.auth.di
+
+import dagger.Module
+import dagger.Provides
+import dagger.hilt.InstallIn
+import dagger.hilt.components.SingletonComponent
+import ing.bikeshedengineer.debtpirate.auth.data.remote.repository.AuthRepository
+import ing.bikeshedengineer.debtpirate.auth.domain.repository.AuthRepositoryImpl
+import ing.bikeshedengineer.debtpirate.auth.domain.usecase.SubmitLoginCredentialsUseCase
+import ing.bikeshedengineer.debtpirate.auth.domain.usecase.ValidateLoginCredentialsUseCase
+import retrofit2.Retrofit
+import javax.inject.Singleton
+
+@Module
+@InstallIn(SingletonComponent::class)
+object AuthDiModule {
+
+    @Provides
+    @Singleton
+    fun provideAuthRepository(httpClient: Retrofit): AuthRepository {
+        return AuthRepositoryImpl(httpClient)
+    }
+
+    @Provides
+    @Singleton
+    fun provideSubmitLoginCredentialsUseCase(authRepository: AuthRepository): SubmitLoginCredentialsUseCase {
+        return SubmitLoginCredentialsUseCase(authRepository)
+    }
+
+    @Provides
+    @Singleton
+    fun provideValidateLoginCredentialsUseCase() = ValidateLoginCredentialsUseCase()
+}

app/app/src/main/java/ing/bikeshedengineer/debtpirate/auth/domain/repository/AuthRepositoryImpl.kt

@@ -1,12 +1,12 @@
-package ing.bikeshedengineer.debtpirate.domain.repository
+package ing.bikeshedengineer.debtpirate.auth.domain.repository
 
 import com.google.gson.Gson
 import com.google.gson.reflect.TypeToken
-import ing.bikeshedengineer.debtpirate.data.remote.endpoint.AuthEndpoint
+import ing.bikeshedengineer.debtpirate.auth.data.remote.endpoint.AuthEndpoint
-import ing.bikeshedengineer.debtpirate.data.remote.model.ApiResponse
+import ing.bikeshedengineer.debtpirate.data.remote.ApiResponse
-import ing.bikeshedengineer.debtpirate.data.remote.model.auth.AuthLoginRequest
+import ing.bikeshedengineer.debtpirate.auth.data.remote.model.AuthLoginRequest
-import ing.bikeshedengineer.debtpirate.data.remote.model.auth.AuthLoginResponse
+import ing.bikeshedengineer.debtpirate.auth.data.remote.model.AuthLoginResponse
-import ing.bikeshedengineer.debtpirate.data.remote.repository.AuthRepository
+import ing.bikeshedengineer.debtpirate.auth.data.remote.repository.AuthRepository
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
 import retrofit2.Retrofit

app/app/src/main/java/ing/bikeshedengineer/debtpirate/auth/domain/usecase/SubmitLoginCredentialsUseCase.kt

@@ -0,0 +1,24 @@
+package ing.bikeshedengineer.debtpirate.auth.domain.usecase
+
+import android.util.Log
+import ing.bikeshedengineer.debtpirate.auth.data.remote.model.AuthLoginRequest
+import ing.bikeshedengineer.debtpirate.auth.data.remote.model.AuthLoginResponse
+import ing.bikeshedengineer.debtpirate.auth.data.remote.repository.AuthRepository
+
+class SubmitLoginCredentialsUseCase(
+    private val authRepository: AuthRepository
+) {
+    suspend operator fun invoke(username: String, password: String): AuthLoginResponse {
+        val credentials = AuthLoginRequest(username, password)
+
+        try {
+            val response = authRepository.submitLoginRequest(credentials)
+            Log.d("AuthScreen", "Login successful! $response")
+            return response
+        } catch (err: Throwable) {
+            // TODO...
+            Log.e("AuthScreen", err.message!!)
+            throw err
+        }
+    }
+}

app/app/src/main/java/ing/bikeshedengineer/debtpirate/auth/domain/usecase/ValidateLoginCredentialsUseCase.kt

@@ -0,0 +1,24 @@
+package ing.bikeshedengineer.debtpirate.auth.domain.usecase
+
+import android.util.Log
+
+sealed class LoginCredentialsValidationResult {
+    object EmptyCredentials : LoginCredentialsValidationResult()
+    object EmptyUsernameField : LoginCredentialsValidationResult()
+    object EmptyPasswordField : LoginCredentialsValidationResult()
+    object ValidCredentials : LoginCredentialsValidationResult()
+}
+
+class ValidateLoginCredentialsUseCase {
+    operator fun invoke(username: String, password: String): LoginCredentialsValidationResult {
+        return if (username.isEmpty() && password.isEmpty()) {
+            LoginCredentialsValidationResult.EmptyCredentials;
+        } else if (username.isEmpty() && password.isNotEmpty()) {
+            LoginCredentialsValidationResult.EmptyUsernameField;
+        } else if (username.isNotEmpty() && password.isEmpty()) {
+            LoginCredentialsValidationResult.EmptyPasswordField
+        } else {
+            LoginCredentialsValidationResult.ValidCredentials
+        }
+    }
+}

app/app/src/main/java/ing/bikeshedengineer/debtpirate/auth/presentation/AuthScreen.kt

@@ -1,4 +1,4 @@
-package ing.bikeshedengineer.debtpirate.presentation.ui.auth
+package ing.bikeshedengineer.debtpirate.auth.presentation
 
 import android.annotation.SuppressLint
 import androidx.compose.foundation.background

app/app/src/main/java/ing/bikeshedengineer/debtpirate/auth/presentation/AuthScreenViewModel.kt

@@ -1,4 +1,4 @@
-package ing.bikeshedengineer.debtpirate.presentation.ui.auth
+package ing.bikeshedengineer.debtpirate.auth.presentation
 
 import android.util.Log
 import androidx.datastore.core.DataStore
@@ -6,24 +6,41 @@ import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import dagger.hilt.android.lifecycle.HiltViewModel
 import ing.bikeshedengineer.debtpirate.PrefsDataStore
-import ing.bikeshedengineer.debtpirate.data.remote.model.auth.AuthLoginRequest
+import ing.bikeshedengineer.debtpirate.auth.data.remote.model.AuthLoginRequest
-import ing.bikeshedengineer.debtpirate.data.remote.repository.AuthRepository
+import ing.bikeshedengineer.debtpirate.auth.data.remote.repository.AuthRepository
+import ing.bikeshedengineer.debtpirate.auth.domain.usecase.LoginCredentialsValidationResult
+import ing.bikeshedengineer.debtpirate.auth.domain.usecase.SubmitLoginCredentialsUseCase
+import ing.bikeshedengineer.debtpirate.auth.domain.usecase.ValidateLoginCredentialsUseCase
 import ing.bikeshedengineer.debtpirate.domain.model.Token
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.asStateFlow
 import kotlinx.coroutines.launch
 import javax.inject.Inject
 
+enum class InvalidField {
+    Username,
+    Password
+}
+
+sealed class FormState {
+    class Pristine : FormState()
+    class Valid : FormState()
+    class Invalid(reason: InvalidReason) : FormState()
+}
+
+enum class InvalidReason {
+    MissingUsernameValue,
+    MissingPasswordValue,
+    PasswordTooShort
+}
+
 @HiltViewModel
 class AuthScreenViewModel @Inject constructor(
     private val authRepository: AuthRepository,
-    private val prefsStore: DataStore<PrefsDataStore>
+    private val prefsStore: DataStore<PrefsDataStore>,
+    private val submitLoginCredentials: SubmitLoginCredentialsUseCase,
+    private val validateLoginCredentials: ValidateLoginCredentialsUseCase,
 ) : ViewModel() {
-    private val tag: String
-        get() {
-            return javaClass.simpleName
-        }
-
 //    private val storeLoginData = StoreLoginDataUseCase(dataStore)
 
     private val _username = MutableStateFlow("")
@@ -41,16 +58,21 @@ class AuthScreenViewModel @Inject constructor(
     }
 
     fun submitLoginRequest() {
-        val credentials = AuthLoginRequest(this._username.value, this._password.value)
+        when (validateLoginCredentials(username.value, password.value)) {
-        viewModelScope.launch {
+            is LoginCredentialsValidationResult.ValidCredentials -> {
-            try {
+                viewModelScope.launch {
-                val response = authRepository.submitLoginRequest(credentials)
+                    try {
-                Log.i(tag, "Login successful! $response")
+                        val result = submitLoginCredentials(username.value, password.value)
-            } catch (err: Throwable) {
+                    } catch (err: Throwable) {
+                        // TODO...
+                    }
+                }
+            }
+            else -> {
                 // TODO...
-                Log.e(tag, err.message!!)
             }
         }
+
     }
 
     fun storeAuthData(userId: Int, sessionToken: Token, authToken: Token) {

app/app/src/main/java/ing/bikeshedengineer/debtpirate/data/remote/ApiResponse.kt

@@ -1,3 +1,3 @@
-package ing.bikeshedengineer.debtpirate.data.remote.model
+package ing.bikeshedengineer.debtpirate.data.remote
 
 data class ApiResponse<T>(val data: T?, val error: String?)

app/app/src/main/java/ing/bikeshedengineer/debtpirate/data/remote/client/AuthEndpointClient.kt

@@ -1,4 +0,0 @@
-package ing.bikeshedengineer.debtpirate.data.remote.client
-
-class AuthEndpointClient {
-}

app/app/src/main/java/ing/bikeshedengineer/debtpirate/data/remote/repository/AuthRepository.kt

@@ -1,8 +0,0 @@
-package ing.bikeshedengineer.debtpirate.data.remote.repository
-
-import ing.bikeshedengineer.debtpirate.data.remote.model.auth.AuthLoginRequest
-import ing.bikeshedengineer.debtpirate.data.remote.model.auth.AuthLoginResponse
-
-interface AuthRepository {
-    suspend fun submitLoginRequest(credentials: AuthLoginRequest): AuthLoginResponse
-}

app/app/src/main/java/ing/bikeshedengineer/debtpirate/di/HttpClientModule.kt

@@ -1,4 +1,4 @@
-package ing.bikeshedengineer.debtpirate.di.modules
+package ing.bikeshedengineer.debtpirate.di
 
 import dagger.Module
 import dagger.Provides

app/app/src/main/java/ing/bikeshedengineer/debtpirate/di/PrefsDataStoreProvider.kt

@@ -1,4 +1,4 @@
-package ing.bikeshedengineer.debtpirate.di.modules
+package ing.bikeshedengineer.debtpirate.di
 
 import android.app.Application
 import androidx.datastore.core.DataStore

app/app/src/main/java/ing/bikeshedengineer/debtpirate/di/modules/AuthRepositoryModule.kt

@@ -1,21 +0,0 @@
-package ing.bikeshedengineer.debtpirate.di.modules
-
-import dagger.Module
-import dagger.Provides
-import dagger.hilt.InstallIn
-import dagger.hilt.components.SingletonComponent
-import ing.bikeshedengineer.debtpirate.data.remote.repository.AuthRepository
-import ing.bikeshedengineer.debtpirate.domain.repository.AuthRepositoryImpl
-import retrofit2.Retrofit
-import javax.inject.Singleton
-
-@Module
-@InstallIn(SingletonComponent::class)
-object AuthRepositoryModule {
-
-    @Provides
-    @Singleton
-    fun provideAuthRepository(httpClient: Retrofit): AuthRepository {
-        return AuthRepositoryImpl(httpClient)
-    }
-}

app/app/src/main/java/ing/bikeshedengineer/debtpirate/theme/Color.kt

@@ -1,4 +1,4 @@
-package ing.bikeshedengineer.debtpirate.presentation.theme
+package ing.bikeshedengineer.debtpirate.theme
 
 import androidx.compose.ui.graphics.Color
 

app/app/src/main/java/ing/bikeshedengineer/debtpirate/theme/Theme.kt

@@ -1,4 +1,4 @@
-package ing.bikeshedengineer.debtpirate.presentation.theme
+package ing.bikeshedengineer.debtpirate.theme
 
 import android.os.Build
 import androidx.compose.foundation.isSystemInDarkTheme

app/app/src/main/java/ing/bikeshedengineer/debtpirate/theme/Type.kt

@@ -1,4 +1,4 @@
-package ing.bikeshedengineer.debtpirate.presentation.theme
+package ing.bikeshedengineer.debtpirate.theme
 
 import androidx.compose.material3.Typography
 import androidx.compose.ui.text.TextStyle