chore: refactor the internal storage layer (#40)

Reviewed-on: #40

composeApp/src/androidMain/kotlin/su/reya/coop/AppStorage.kt

@@ -1,8 +1,13 @@
-package su.reya.coop.coop.storage
+package su.reya.coop
 
+import android.content.Context
 import android.security.keystore.KeyGenParameterSpec
 import android.security.keystore.KeyProperties
 import android.util.Base64
+import androidx.datastore.preferences.core.edit
+import androidx.datastore.preferences.core.stringPreferencesKey
+import androidx.datastore.preferences.preferencesDataStore
+import kotlinx.coroutines.flow.first
 import java.nio.charset.StandardCharsets
 import java.security.KeyStore
 import javax.crypto.Cipher
@@ -10,10 +15,9 @@ import javax.crypto.KeyGenerator
 import javax.crypto.SecretKey
 import javax.crypto.spec.GCMParameterSpec
 
-data class SecretEntry(
+private val Context.dataStore by preferencesDataStore("secret_store")
-    val encrypted: String,
+
-    val iv: String
+data class SecretEntry(val encrypted: String, val iv: String)
-)
 
 class SecretCrypto {
     private val keyAlias = "coop"
@@ -21,11 +25,9 @@ class SecretCrypto {
     private val transformation = "AES/GCM/NoPadding"
 
     fun encrypt(content: String): SecretEntry {
-        // Initialize cipher
         val cipher = Cipher.getInstance(transformation)
         cipher.init(Cipher.ENCRYPT_MODE, getOrCreateKey())
 
-        // Encrypt content
         val encrypted = cipher.doFinal(content.toByteArray())
         val iv = cipher.iv
 
@@ -39,12 +41,10 @@ class SecretCrypto {
         val encrypted = Base64.decode(entry.encrypted, Base64.NO_WRAP)
         val iv = Base64.decode(entry.iv, Base64.NO_WRAP)
 
-        // Initialize cipher
         val cipher = Cipher.getInstance(transformation)
         val spec = GCMParameterSpec(128, iv)
         cipher.init(Cipher.DECRYPT_MODE, getOrCreateKey(), spec)
 
-        // Decrypt content
         val plaintext = cipher.doFinal(encrypted)
 
         return String(plaintext, StandardCharsets.UTF_8)
@@ -54,13 +54,9 @@ class SecretCrypto {
         val keyStore = KeyStore.getInstance(keyStoreType).apply { load(null) }
         val existingKey = keyStore.getKey(keyAlias, null)
 
-        // Return existing key if available
         if (existingKey is SecretKey) return existingKey
 
-        // Construct a new key generator
         val keyGenerator = KeyGenerator.getInstance(KeyProperties.KEY_ALGORITHM_AES, keyStoreType)
-
-        // Initialize key generation parameters
         val spec = KeyGenParameterSpec.Builder(
             keyAlias,
             KeyProperties.PURPOSE_ENCRYPT or KeyProperties.PURPOSE_DECRYPT
@@ -70,9 +66,49 @@ class SecretCrypto {
             .setKeySize(256)
             .build()
 
-        // Generate a new key
         keyGenerator.init(spec)
-
         return keyGenerator.generateKey()
     }
 }
+
+class AppStore(private val context: Context) : AppStorage {
+    private val crypto = SecretCrypto()
+
+    override suspend fun get(key: String): String? {
+        return context.dataStore.data.first()[stringPreferencesKey(key)]
+    }
+
+    override suspend fun set(key: String, value: String) {
+        context.dataStore.edit { it[stringPreferencesKey(key)] = value }
+    }
+
+    override suspend fun getSecret(key: String): String? {
+        val prefs = context.dataStore.data.first()
+        val encrypted = prefs[stringPreferencesKey("${key}_encrypted")] ?: return null
+        val iv = prefs[stringPreferencesKey("${key}_iv")] ?: return null
+
+        return crypto.decrypt(SecretEntry(encrypted, iv))
+    }
+
+    override suspend fun setSecret(key: String, value: String) {
+        val entry = crypto.encrypt(value)
+        context.dataStore.edit { prefs ->
+            prefs[stringPreferencesKey("${key}_encrypted")] = entry.encrypted
+            prefs[stringPreferencesKey("${key}_iv")] = entry.iv
+        }
+    }
+
+    override suspend fun clear(key: String) {
+        context.dataStore.edit { prefs ->
+            prefs.remove(stringPreferencesKey(key))
+            prefs.remove(stringPreferencesKey("${key}_encrypted"))
+            prefs.remove(stringPreferencesKey("${key}_iv"))
+        }
+    }
+
+    override suspend fun has(key: String): Boolean {
+        val prefs = context.dataStore.data.first()
+        return prefs.contains(stringPreferencesKey(key)) ||
+                prefs.contains(stringPreferencesKey("${key}_encrypted"))
+    }
+}

composeApp/src/androidMain/kotlin/su/reya/coop/MainActivity.kt

@@ -12,7 +12,6 @@ import androidx.activity.viewModels
 import androidx.core.splashscreen.SplashScreen.Companion.installSplashScreen
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.ViewModelProvider
-import su.reya.coop.coop.storage.SecretStore
 import su.reya.coop.nostr.NostrManager
 import su.reya.coop.viewmodel.AuthViewModel
 import su.reya.coop.viewmodel.ChatViewModel
@@ -26,15 +25,13 @@ class MainActivity : ComponentActivity() {
 
     private val factory by lazy {
         object : ViewModelProvider.Factory {
+            private val storage = AppStore(this@MainActivity)
+            private val nostrViewModel = NostrViewModel(NostrManager.instance)
+            private val chatViewModel = ChatViewModel(NostrManager.instance)
             private val androidSigner =
                 AndroidExternalSigner(this@MainActivity, externalSignerLauncher)
-            private val secretStore = SecretStore(this@MainActivity)
-            private val nostrViewModel =
-                NostrViewModel(NostrManager.instance)
-            private val chatViewModel =
-                ChatViewModel(NostrManager.instance)
             private val authViewModel =
-                AuthViewModel(NostrManager.instance, secretStore, androidSigner)
+                AuthViewModel(NostrManager.instance, storage, androidSigner)
 
             override fun <T : ViewModel> create(modelClass: Class<T>): T {
                 return when {

composeApp/src/androidMain/kotlin/su/reya/coop/storage/SecretStore.kt

@@ -1,43 +0,0 @@
-package su.reya.coop.coop.storage
-
-import android.content.Context
-import androidx.datastore.preferences.core.edit
-import androidx.datastore.preferences.core.stringPreferencesKey
-import androidx.datastore.preferences.preferencesDataStore
-import kotlinx.coroutines.flow.first
-import su.reya.coop.storage.SecretStorage
-
-private val Context.dataStore by preferencesDataStore("secret_store")
-
-class SecretStore(private val context: Context) : SecretStorage {
-    private val crypto = SecretCrypto()
-
-    override suspend fun set(key: String, value: String) {
-        val entry = crypto.encrypt(value)
-
-        context.dataStore.edit { prefs ->
-            prefs[stringPreferencesKey("${key}_encrypted")] = entry.encrypted
-            prefs[stringPreferencesKey("${key}_iv")] = entry.iv
-        }
-    }
-
-    override suspend fun get(key: String): String? {
-        val prefs = context.dataStore.data.first()
-        val encrypted = prefs[stringPreferencesKey("${key}_encrypted")] ?: return null
-        val iv = prefs[stringPreferencesKey("${key}_iv")] ?: return null
-
-        return crypto.decrypt(SecretEntry(encrypted, iv))
-    }
-
-    override suspend fun clear(key: String) {
-        context.dataStore.edit { prefs ->
-            prefs.remove(stringPreferencesKey("${key}_encrypted"))
-            prefs.remove(stringPreferencesKey("${key}_iv"))
-        }
-    }
-
-    override suspend fun has(key: String): Boolean {
-        val prefs = context.dataStore.data.first()
-        return prefs[stringPreferencesKey("${key}_encrypted")] != null
-    }
-}

shared/build.gradle.kts

@@ -33,6 +33,8 @@ kotlin {
             implementation(libs.ktor.serialization.kotlinx.json)
             implementation(libs.androidx.lifecycle.viewmodelCompose)
             implementation(libs.androidx.lifecycle.runtimeCompose)
+            implementation(libs.androidx.datastore.preferences)
+            implementation(libs.androidx.datastore)
             implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.11.0")
             implementation("org.jetbrains.kotlinx:kotlinx-datetime:0.8.0")
             implementation("su.reya:nostr-sdk-kmp:0.3.2")

shared/src/commonMain/kotlin/su/reya/coop/AppStorage.kt

@@ -0,0 +1,14 @@
+package su.reya.coop
+
+interface AppStorage {
+    // Plain text storage
+    suspend fun get(key: String): String?
+    suspend fun set(key: String, value: String)
+
+    // Encrypted storage
+    suspend fun getSecret(key: String): String?
+    suspend fun setSecret(key: String, value: String)
+
+    suspend fun clear(key: String)
+    suspend fun has(key: String): Boolean
+}

shared/src/commonMain/kotlin/su/reya/coop/storage/SecretStorage.kt

@@ -1,8 +0,0 @@
-package su.reya.coop.storage
-
-interface SecretStorage {
-    suspend fun get(key: String): String?
-    suspend fun set(key: String, value: String)
-    suspend fun clear(key: String)
-    suspend fun has(key: String): Boolean
-}

shared/src/commonMain/kotlin/su/reya/coop/viewmodel/AuthViewModel.kt

@@ -12,12 +12,12 @@ import rust.nostr.sdk.Keys
 import rust.nostr.sdk.NostrConnect
 import rust.nostr.sdk.NostrConnectUri
 import rust.nostr.sdk.PublicKey
+import su.reya.coop.AppStorage
 import su.reya.coop.nostr.ExternalSignerHandler
 import su.reya.coop.nostr.ExternalSignerProxy
 import su.reya.coop.nostr.Nostr
 import su.reya.coop.nostr.SignerPermissions
 import su.reya.coop.repository.MediaRepository
-import su.reya.coop.storage.SecretStorage
 import kotlin.time.Duration.Companion.seconds
 
 data class AuthState(
@@ -27,7 +27,7 @@ data class AuthState(
 
 class AuthViewModel(
     private val nostr: Nostr,
-    private val secretStore: SecretStorage,
+    private val storage: AppStorage,
     private val externalSignerHandler: ExternalSignerHandler? = null,
 ) : BaseViewModel() {
     private val mediaRepository = MediaRepository()
@@ -51,7 +51,7 @@ class AuthViewModel(
 
     private fun checkNotificationBannerDismissedStatus() {
         viewModelScope.launch {
-            val dismissed = secretStore.get(KEY_BANNER_DISMISSED) == "true"
+            val dismissed = storage.get(KEY_BANNER_DISMISSED) == "true"
             _state.update { it.copy(isNotificationBannerDismissed = dismissed) }
         }
     }
@@ -60,7 +60,7 @@ class AuthViewModel(
         viewModelScope.launch {
             try {
                 val secret = withTimeoutOrNull(5.seconds) {
-                    secretStore.get(KEY_USER_SIGNER)
+                    storage.getSecret(KEY_USER_SIGNER)
                 }
 
                 if (secret == null) {
@@ -94,8 +94,8 @@ class AuthViewModel(
                 showError("Logout encountered an error: ${e.message}")
             } finally {
                 // Clear credentials from persistent storage
-                secretStore.clear(KEY_USER_SIGNER)
+                storage.clear(KEY_USER_SIGNER)
-                secretStore.clear(KEY_BANNER_DISMISSED)
+                storage.clear(KEY_BANNER_DISMISSED)
                 // Call cleanup callback (e.g. to reset other ViewModels)
                 onLogout()
                 // Reset local states
@@ -106,18 +106,18 @@ class AuthViewModel(
 
     fun dismissNotificationBanner() {
         viewModelScope.launch {
-            secretStore.set(KEY_BANNER_DISMISSED, "true")
+            storage.set(KEY_BANNER_DISMISSED, "true")
             _state.update { it.copy(isNotificationBannerDismissed = true) }
         }
     }
 
     private suspend fun getOrInitAppKeys(): Keys {
-        val secret = secretStore.get(KEY_APP_KEYS)
+        val secret = storage.getSecret(KEY_APP_KEYS)
         // If app keys are already stored, use them
         if (secret != null) return Keys.parse(secret)
         // Generate new app keys and save to the secret storage
         val keys = Keys.generate()
-        secretStore.set(KEY_APP_KEYS, keys.secretKey().toBech32())
+        storage.setSecret(KEY_APP_KEYS, keys.secretKey().toBech32())
         return keys
     }
 
@@ -166,7 +166,7 @@ class AuthViewModel(
         // Update signer
         nostr.setSigner(signer)
         // Persist the secret in the secret storage
-        secretStore.set(KEY_USER_SIGNER, decryptedSecret ?: secret)
+        storage.setSecret(KEY_USER_SIGNER, decryptedSecret ?: secret)
         // Update local states
         _state.update { it.copy(signerRequired = false) }
     }
@@ -195,7 +195,7 @@ class AuthViewModel(
         // Update signer
         nostr.setSigner(signer)
         // Store the signer in the secret storage
-        secretStore.set(KEY_USER_SIGNER, "nip55://${result.packageName}/${result.pubkey.toHex()}")
+        storage.setSecret(KEY_USER_SIGNER, "nip55://${result.packageName}/${result.pubkey.toHex()}")
         // Update local states
         _state.update { it.copy(signerRequired = false) }
     }
@@ -218,7 +218,7 @@ class AuthViewModel(
         // Create identity
         nostr.profiles.createIdentity(keys = keys, name = name, bio = bio, picture = avatarUrl)
         // Persist the secret in the secret storage
-        secretStore.set(KEY_USER_SIGNER, secret)
+        storage.setSecret(KEY_USER_SIGNER, secret)
         // Update local states
         _state.update { it.copy(signerRequired = false) }
     }