refactor(client/kotlin): remove interface layer that seemed redundant (#6102)

I'm opening PRs for small refactors around the code I'm changing for
adding the Favorites menu.

Just anything where I read it and, as a Kotlin noobie, took longer than
expected to understand

kotlin/android/app/src/main/java/dev/firezone/android/core/data/Repository.kt

@@ -1,59 +1,174 @@
 /* Licensed under Apache 2.0 (C) 2024 Firezone, Inc. */
 package dev.firezone.android.core.data
 
+import android.content.Context
+import android.content.SharedPreferences
+import dev.firezone.android.BuildConfig
 import dev.firezone.android.core.data.model.Config
+import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.flow
+import kotlinx.coroutines.flow.flowOn
+import java.security.MessageDigest
+import javax.inject.Inject
 
-interface Repository {
-    fun getConfigSync(): Config
+internal class Repository
+    @Inject
+    constructor(
+        private val context: Context,
+        private val coroutineDispatcher: CoroutineDispatcher,
+        private val sharedPreferences: SharedPreferences,
+    ) {
+        fun getConfigSync(): Config {
+            return Config(
+                sharedPreferences.getString(AUTH_BASE_URL_KEY, null)
+                    ?: BuildConfig.AUTH_BASE_URL,
+                sharedPreferences.getString(API_URL_KEY, null)
+                    ?: BuildConfig.API_URL,
+                sharedPreferences.getString(LOG_FILTER_KEY, null)
+                    ?: BuildConfig.LOG_FILTER,
+            )
+        }
 
-    fun getConfig(): Flow<Config>
+        fun getConfig(): Flow<Config> =
+            flow {
+                emit(getConfigSync())
+            }.flowOn(coroutineDispatcher)
 
-    fun getDefaultConfigSync(): Config
+        fun getDefaultConfigSync(): Config =
+            Config(
+                BuildConfig.AUTH_BASE_URL,
+                BuildConfig.API_URL,
+                BuildConfig.LOG_FILTER,
+            )
 
-    fun getDefaultConfig(): Flow<Config>
+        fun getDefaultConfig(): Flow<Config> =
+            flow {
+                emit(getDefaultConfigSync())
+            }.flowOn(coroutineDispatcher)
 
-    fun saveSettings(
-        authBaseUrl: String,
-        apiUrl: String,
-        logFilter: String,
-    ): Flow<Unit>
+        fun saveSettings(
+            authBaseUrl: String,
+            apiUrl: String,
+            logFilter: String,
+        ): Flow<Unit> =
+            flow {
+                emit(
+                    sharedPreferences
+                        .edit()
+                        .putString(AUTH_BASE_URL_KEY, authBaseUrl)
+                        .putString(API_URL_KEY, apiUrl)
+                        .putString(LOG_FILTER_KEY, logFilter)
+                        .apply(),
+                )
+            }.flowOn(coroutineDispatcher)
 
-    fun saveDeviceIdSync(value: String): Unit
+        fun getDeviceIdSync(): String? = sharedPreferences.getString(DEVICE_ID_KEY, null)
 
-    fun getToken(): Flow<String?>
+        fun getToken(): Flow<String?> =
+            flow {
+                emit(sharedPreferences.getString(TOKEN_KEY, null))
+            }.flowOn(coroutineDispatcher)
 
-    fun getTokenSync(): String?
+        fun getTokenSync(): String? = sharedPreferences.getString(TOKEN_KEY, null)
 
-    fun getStateSync(): String?
+        fun getStateSync(): String? = sharedPreferences.getString(STATE_KEY, null)
 
-    fun getNonceSync(): String?
+        fun getActorName(): Flow<String?> =
+            flow {
+                emit(getActorNameSync())
+            }.flowOn(coroutineDispatcher)
 
-    fun getDeviceIdSync(): String?
+        fun getActorNameSync(): String? =
+            sharedPreferences.getString(ACTOR_NAME_KEY, null)?.let {
+                if (it.isNotEmpty()) "Signed in as $it" else "Signed in"
+            }
 
-    fun getActorName(): Flow<String?>
+        fun getNonceSync(): String? = sharedPreferences.getString(NONCE_KEY, null)
 
-    fun getActorNameSync(): String?
+        fun saveDeviceIdSync(value: String): Unit =
+            sharedPreferences
+                .edit()
+                .putString(DEVICE_ID_KEY, value)
+                .apply()
 
-    fun saveNonce(value: String): Flow<Unit>
+        fun saveNonce(value: String): Flow<Unit> =
+            flow {
+                emit(saveNonceSync(value))
+            }.flowOn(coroutineDispatcher)
 
-    fun saveState(value: String): Flow<Unit>
+        fun saveNonceSync(value: String) = sharedPreferences.edit().putString(NONCE_KEY, value).apply()
 
-    fun saveStateSync(value: String): Unit
+        fun saveState(value: String): Flow<Unit> =
+            flow {
+                emit(saveStateSync(value))
+            }.flowOn(coroutineDispatcher)
 
-    fun saveNonceSync(value: String): Unit
+        fun saveStateSync(value: String) = sharedPreferences.edit().putString(STATE_KEY, value).apply()
 
-    fun saveToken(value: String): Flow<Unit>
+        fun saveToken(value: String): Flow<Unit> =
+            flow {
+                val nonce = sharedPreferences.getString(NONCE_KEY, "").orEmpty()
+                emit(
+                    sharedPreferences
+                        .edit()
+                        .putString(TOKEN_KEY, nonce.plus(value))
+                        .apply(),
+                )
+            }.flowOn(coroutineDispatcher)
 
-    fun saveActorName(value: String): Flow<Unit>
+        fun saveActorName(value: String): Flow<Unit> =
+            flow {
+                emit(
+                    sharedPreferences
+                        .edit()
+                        .putString(ACTOR_NAME_KEY, value)
+                        .apply(),
+                )
+            }.flowOn(coroutineDispatcher)
 
-    fun validateState(value: String): Flow<Boolean>
+        fun validateState(value: String): Flow<Boolean> =
+            flow {
+                val state = sharedPreferences.getString(STATE_KEY, "").orEmpty()
+                emit(MessageDigest.isEqual(state.toByteArray(), value.toByteArray()))
+            }.flowOn(coroutineDispatcher)
 
-    fun clearToken()
+        fun clearToken() {
+            sharedPreferences.edit().apply {
+                remove(TOKEN_KEY)
+                apply()
+            }
+        }
 
-    fun clearNonce()
+        fun clearNonce() {
+            sharedPreferences.edit().apply {
+                remove(NONCE_KEY)
+                apply()
+            }
+        }
 
-    fun clearState()
+        fun clearState() {
+            sharedPreferences.edit().apply {
+                remove(STATE_KEY)
+                apply()
+            }
+        }
 
-    fun clearActorName()
-}
+        fun clearActorName() {
+            sharedPreferences.edit().apply {
+                remove(ACTOR_NAME_KEY)
+                apply()
+            }
+        }
+
+        companion object {
+            private const val AUTH_BASE_URL_KEY = "authBaseUrl"
+            private const val ACTOR_NAME_KEY = "actorName"
+            private const val API_URL_KEY = "apiUrl"
+            private const val LOG_FILTER_KEY = "logFilter"
+            private const val TOKEN_KEY = "token"
+            private const val NONCE_KEY = "nonce"
+            private const val STATE_KEY = "state"
+            private const val DEVICE_ID_KEY = "deviceId"
+        }
+    }

kotlin/android/app/src/main/java/dev/firezone/android/core/data/RepositoryImpl.kt

@@ -1,174 +0,0 @@
-/* Licensed under Apache 2.0 (C) 2024 Firezone, Inc. */
-package dev.firezone.android.core.data
-
-import android.content.Context
-import android.content.SharedPreferences
-import dev.firezone.android.BuildConfig
-import dev.firezone.android.core.data.model.Config
-import kotlinx.coroutines.CoroutineDispatcher
-import kotlinx.coroutines.flow.Flow
-import kotlinx.coroutines.flow.flow
-import kotlinx.coroutines.flow.flowOn
-import java.security.MessageDigest
-import javax.inject.Inject
-
-internal class RepositoryImpl
-    @Inject
-    constructor(
-        private val context: Context,
-        private val coroutineDispatcher: CoroutineDispatcher,
-        private val sharedPreferences: SharedPreferences,
-    ) : Repository {
-        override fun getConfigSync(): Config {
-            return Config(
-                sharedPreferences.getString(AUTH_BASE_URL_KEY, null)
-                    ?: BuildConfig.AUTH_BASE_URL,
-                sharedPreferences.getString(API_URL_KEY, null)
-                    ?: BuildConfig.API_URL,
-                sharedPreferences.getString(LOG_FILTER_KEY, null)
-                    ?: BuildConfig.LOG_FILTER,
-            )
-        }
-
-        override fun getConfig(): Flow<Config> =
-            flow {
-                emit(getConfigSync())
-            }.flowOn(coroutineDispatcher)
-
-        override fun getDefaultConfigSync(): Config =
-            Config(
-                BuildConfig.AUTH_BASE_URL,
-                BuildConfig.API_URL,
-                BuildConfig.LOG_FILTER,
-            )
-
-        override fun getDefaultConfig(): Flow<Config> =
-            flow {
-                emit(getDefaultConfigSync())
-            }.flowOn(coroutineDispatcher)
-
-        override fun saveSettings(
-            authBaseUrl: String,
-            apiUrl: String,
-            logFilter: String,
-        ): Flow<Unit> =
-            flow {
-                emit(
-                    sharedPreferences
-                        .edit()
-                        .putString(AUTH_BASE_URL_KEY, authBaseUrl)
-                        .putString(API_URL_KEY, apiUrl)
-                        .putString(LOG_FILTER_KEY, logFilter)
-                        .apply(),
-                )
-            }.flowOn(coroutineDispatcher)
-
-        override fun getDeviceIdSync(): String? = sharedPreferences.getString(DEVICE_ID_KEY, null)
-
-        override fun getToken(): Flow<String?> =
-            flow {
-                emit(sharedPreferences.getString(TOKEN_KEY, null))
-            }.flowOn(coroutineDispatcher)
-
-        override fun getTokenSync(): String? = sharedPreferences.getString(TOKEN_KEY, null)
-
-        override fun getStateSync(): String? = sharedPreferences.getString(STATE_KEY, null)
-
-        override fun getActorName(): Flow<String?> =
-            flow {
-                emit(getActorNameSync())
-            }.flowOn(coroutineDispatcher)
-
-        override fun getActorNameSync(): String? =
-            sharedPreferences.getString(ACTOR_NAME_KEY, null)?.let {
-                if (it.isNotEmpty()) "Signed in as $it" else "Signed in"
-            }
-
-        override fun getNonceSync(): String? = sharedPreferences.getString(NONCE_KEY, null)
-
-        override fun saveDeviceIdSync(value: String): Unit =
-            sharedPreferences
-                .edit()
-                .putString(DEVICE_ID_KEY, value)
-                .apply()
-
-        override fun saveNonce(value: String): Flow<Unit> =
-            flow {
-                emit(saveNonceSync(value))
-            }.flowOn(coroutineDispatcher)
-
-        override fun saveNonceSync(value: String) = sharedPreferences.edit().putString(NONCE_KEY, value).apply()
-
-        override fun saveState(value: String): Flow<Unit> =
-            flow {
-                emit(saveStateSync(value))
-            }.flowOn(coroutineDispatcher)
-
-        override fun saveStateSync(value: String) = sharedPreferences.edit().putString(STATE_KEY, value).apply()
-
-        override fun saveToken(value: String): Flow<Unit> =
-            flow {
-                val nonce = sharedPreferences.getString(NONCE_KEY, "").orEmpty()
-                emit(
-                    sharedPreferences
-                        .edit()
-                        .putString(TOKEN_KEY, nonce.plus(value))
-                        .apply(),
-                )
-            }.flowOn(coroutineDispatcher)
-
-        override fun saveActorName(value: String): Flow<Unit> =
-            flow {
-                emit(
-                    sharedPreferences
-                        .edit()
-                        .putString(ACTOR_NAME_KEY, value)
-                        .apply(),
-                )
-            }.flowOn(coroutineDispatcher)
-
-        override fun validateState(value: String): Flow<Boolean> =
-            flow {
-                val state = sharedPreferences.getString(STATE_KEY, "").orEmpty()
-                emit(MessageDigest.isEqual(state.toByteArray(), value.toByteArray()))
-            }.flowOn(coroutineDispatcher)
-
-        override fun clearToken() {
-            sharedPreferences.edit().apply {
-                remove(TOKEN_KEY)
-                apply()
-            }
-        }
-
-        override fun clearNonce() {
-            sharedPreferences.edit().apply {
-                remove(NONCE_KEY)
-                apply()
-            }
-        }
-
-        override fun clearState() {
-            sharedPreferences.edit().apply {
-                remove(STATE_KEY)
-                apply()
-            }
-        }
-
-        override fun clearActorName() {
-            sharedPreferences.edit().apply {
-                remove(ACTOR_NAME_KEY)
-                apply()
-            }
-        }
-
-        companion object {
-            private const val AUTH_BASE_URL_KEY = "authBaseUrl"
-            private const val ACTOR_NAME_KEY = "actorName"
-            private const val API_URL_KEY = "apiUrl"
-            private const val LOG_FILTER_KEY = "logFilter"
-            private const val TOKEN_KEY = "token"
-            private const val NONCE_KEY = "nonce"
-            private const val STATE_KEY = "state"
-            private const val DEVICE_ID_KEY = "deviceId"
-        }
-    }

kotlin/android/app/src/main/java/dev/firezone/android/core/di/DataModule.kt

@@ -11,7 +11,6 @@ import dagger.hilt.InstallIn
 import dagger.hilt.android.qualifiers.ApplicationContext
 import dagger.hilt.components.SingletonComponent
 import dev.firezone.android.core.data.Repository
-import dev.firezone.android.core.data.RepositoryImpl
 import kotlinx.coroutines.CoroutineDispatcher
 
 @Module
@@ -28,7 +27,7 @@ class DataModule {
         @IoDispatcher coroutineDispatcher: CoroutineDispatcher,
         sharedPreferences: SharedPreferences,
     ): Repository =
-        RepositoryImpl(
+        Repository(
             context,
             coroutineDispatcher,
             sharedPreferences,

kotlin/android/app/src/main/java/dev/firezone/android/features/auth/ui/AuthViewModel.kt

@@ -28,7 +28,7 @@ internal class AuthViewModel
                 val nonce = generateRandomString(NONCE_LENGTH)
                 repo.saveNonceSync(nonce)
                 repo.saveStateSync(state)
-                val config = repo.getConfigSync()!!
+                val config = repo.getConfigSync()
                 val token = repo.getTokenSync()
 
                 actionMutableLiveData.postValue(