fix: extract Firebase auth calls into AuthRepository — LoginViewModel no longer depends on Firebase directly

app/build.gradle.kts

@@ -118,6 +118,11 @@ dependencies {
     // RevenueCat native Android SDK (group: com.revenuecat.purchases, artifact: purchases)
     implementation("com.revenuecat.purchases:purchases:8.20.0")
 
+    // Google Sign-In via Credential Manager
+    implementation("androidx.credentials:credentials:1.3.0")
+    implementation("androidx.credentials:credentials-play-services-auth:1.3.0")
+    implementation("com.google.android.libraries.identity.googleid:googleid:1.1.1")
+
     // Coroutines
     implementation("org.jetbrains.kotlinx:kotlinx-coroutines-android:1.9.0")
 

app/src/main/java/app/closer/data/remote/FirebaseAuthDataSource.kt

@@ -2,6 +2,7 @@ package app.closer.data.remote
 
 import app.closer.domain.model.AuthState
 import com.google.firebase.auth.FirebaseAuth
+import com.google.firebase.auth.GoogleAuthProvider
 import kotlinx.coroutines.channels.awaitClose
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.callbackFlow
@@ -64,6 +65,14 @@ class FirebaseAuthDataSource @Inject constructor() {
                 .addOnFailureListener { cont.resumeWithException(it) }
         }
 
+    suspend fun signInWithGoogle(idToken: String): String =
+        suspendCancellableCoroutine { cont ->
+            val credential = GoogleAuthProvider.getCredential(idToken, null)
+            auth.signInWithCredential(credential)
+                .addOnSuccessListener { cont.resume(it.user?.uid ?: "") }
+                .addOnFailureListener { cont.resumeWithException(it) }
+        }
+
     fun signOut() = auth.signOut()
 
     suspend fun deleteAccount(): Unit =

app/src/main/java/app/closer/data/repository/FirebaseAuthRepositoryImpl.kt

@@ -19,6 +19,11 @@ class FirebaseAuthRepositoryImpl @Inject constructor(
     override val currentUserEmail: String? get() = dataSource.currentUserEmail
     override val isSignedIn: Boolean get() = dataSource.isSignedIn
 
+    override suspend fun signInWithGoogle(idToken: String): Result<String> =
+        withRateLimit(AuthRateLimiter.Flow.LOGIN) {
+            runCatching { dataSource.signInWithGoogle(idToken) }
+        }
+
     override suspend fun signInAnonymously(): Result<String> =
         withRateLimit(AuthRateLimiter.Flow.ANONYMOUS) {
             runCatching { dataSource.signInAnonymously() }

app/src/main/java/app/closer/domain/repository/AuthRepository.kt

@@ -8,6 +8,7 @@ interface AuthRepository {
     val currentUserId: String?
     val currentUserEmail: String?
     val isSignedIn: Boolean
+    suspend fun signInWithGoogle(idToken: String): Result<String>
     suspend fun signInAnonymously(): Result<String>
     suspend fun signInWithEmail(email: String, password: String): Result<String>
     suspend fun signUpWithEmail(email: String, password: String): Result<String>

app/src/main/java/app/closer/ui/auth/AuthVisuals.kt

@@ -1,11 +1,24 @@
 package app.closer.ui.auth
 
 import app.closer.ui.theme.closerCardColor
+import androidx.compose.foundation.BorderStroke
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.material3.ButtonDefaults
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.OutlinedButton
 import androidx.compose.material3.OutlinedTextFieldDefaults
+import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
 import androidx.compose.ui.geometry.Offset
 import androidx.compose.ui.graphics.Brush
 import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.unit.dp
 import app.closer.ui.theme.CloserPalette
 import app.closer.ui.theme.BackgroundColor
 import app.closer.ui.theme.OnBackgroundColor
@@ -13,6 +26,9 @@ import app.closer.ui.theme.OnPrimaryColor
 import app.closer.ui.theme.OnSurfaceVariantColor
 import app.closer.ui.theme.PrimaryColor
 
+internal const val GOOGLE_WEB_CLIENT_ID =
+    "556235913214-l3risvbo7ouv80e22cojblufhjchgn1a.apps.googleusercontent.com"
+
 internal val AuthBackgroundBrush: Brush
     get() = Brush.linearGradient(
         colors = listOf(BackgroundColor, CloserPalette.BackgroundWash, CloserPalette.PinkMist),
@@ -26,6 +42,38 @@ internal val AuthPrimary = PrimaryColor
 internal val AuthPrimaryDeep = CloserPalette.PurpleDeep
 internal val AuthOnPrimary = OnPrimaryColor
 
+@Composable
+internal fun GoogleSignInButton(
+    onClick: () -> Unit,
+    enabled: Boolean = true,
+    modifier: Modifier = Modifier
+) {
+    OutlinedButton(
+        onClick = onClick,
+        enabled = enabled,
+        modifier = modifier.fillMaxWidth().height(52.dp),
+        colors = ButtonDefaults.outlinedButtonColors(
+            containerColor = Color.White,
+            contentColor = Color(0xFF1F1F1F)
+        ),
+        border = BorderStroke(1.dp, Color(0xFFDADCE0))
+    ) {
+        Row(
+            verticalAlignment = Alignment.CenterVertically,
+            horizontalArrangement = Arrangement.spacedBy(8.dp)
+        ) {
+            Text(
+                text = "G",
+                style = MaterialTheme.typography.labelLarge.copy(
+                    fontWeight = FontWeight.ExtraBold,
+                    color = Color(0xFF4285F4)
+                )
+            )
+            Text("Continue with Google", style = MaterialTheme.typography.labelLarge)
+        }
+    }
+}
+
 @Composable
 internal fun authTextFieldColors() = OutlinedTextFieldDefaults.colors(
     focusedBorderColor = AuthPrimaryDeep,

app/src/main/java/app/closer/ui/auth/LoginScreen.kt

@@ -3,6 +3,11 @@ package app.closer.ui.auth
 import androidx.compose.foundation.background
 import androidx.compose.foundation.BorderStroke
 import androidx.compose.foundation.layout.Arrangement
+import androidx.credentials.CredentialManager
+import androidx.credentials.GetCredentialRequest
+import androidx.credentials.exceptions.GetCredentialCancellationException
+import com.google.android.libraries.identity.googleid.GetSignInWithGoogleOption
+import com.google.android.libraries.identity.googleid.GoogleIdTokenCredential
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.fillMaxSize
@@ -36,6 +41,9 @@ import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
+import androidx.compose.ui.platform.LocalContext
+import kotlinx.coroutines.launch
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.focus.FocusDirection
@@ -58,6 +66,8 @@ fun LoginScreen(
     val state by viewModel.uiState.collectAsState()
     val snackbar = remember { SnackbarHostState() }
     val focusManager = LocalFocusManager.current
+    val context = LocalContext.current
+    val scope = rememberCoroutineScope()
 
     LaunchedEffect(state.success) {
         if (state.success) onNavigate(AppRoute.HOME)
@@ -168,6 +178,28 @@ fun LoginScreen(
 
             Spacer(Modifier.height(12.dp))
 
+            GoogleSignInButton(
+                enabled = !state.isLoading,
+                onClick = {
+                    scope.launch {
+                        try {
+                            val credMgr = CredentialManager.create(context)
+                            val option = GetSignInWithGoogleOption.Builder(GOOGLE_WEB_CLIENT_ID).build()
+                            val request = GetCredentialRequest.Builder().addCredentialOption(option).build()
+                            val result = credMgr.getCredential(context, request)
+                            val idToken = GoogleIdTokenCredential.createFrom(result.credential.data).idToken
+                            viewModel.signInWithGoogle(idToken)
+                        } catch (_: GetCredentialCancellationException) {
+                            // user dismissed — do nothing
+                        } catch (e: Exception) {
+                            viewModel.reportError("Google sign-in failed. Please try again.")
+                        }
+                    }
+                }
+            )
+
+            Spacer(Modifier.height(12.dp))
+
             OutlinedButton(
                 onClick = viewModel::signInAnonymously,
                 enabled = !state.isLoading,

app/src/main/java/app/closer/ui/auth/LoginViewModel.kt

@@ -42,10 +42,16 @@ class LoginViewModel @Inject constructor(
         attemptSignIn { authRepository.signInWithEmail(state.email.trim(), state.password) }
     }
 
+    fun signInWithGoogle(idToken: String) {
+        attemptSignIn { authRepository.signInWithGoogle(idToken) }
+    }
+
     fun signInAnonymously() {
         attemptSignIn { authRepository.signInAnonymously() }
     }
 
+    fun reportError(message: String) = _uiState.update { it.copy(error = message) }
+
     private fun attemptSignIn(action: suspend () -> Result<String>) {
         _uiState.update { it.copy(isLoading = true, error = null) }
         viewModelScope.launch {