Add Google sign-up and sign-in

.gitignore

@@ -36,4 +36,5 @@ app/google-services.json
 secrets.properties
 
 # Mac
-.DS_store
+.DS_store
+.kotlin/

README.md

@@ -11,3 +11,17 @@ Score is Cornell’s all-in-one sports discovery hub that makes Cornell sports e
     - `secrets.properties`
 4. Add `secrets.properties` to the project root and `google-services.json` to the app level in Android Studio
 5. Build and run!
+
+## Authentication
+
+Google sign-in uses Credential Manager and Firebase Authentication, then exchanges the Firebase ID token for Score backend tokens. Enable Google as a sign-in provider in Firebase, register the Android signing SHA-1 and SHA-256 fingerprints, and install the updated `app/google-services.json`. The file must include the web OAuth client so the Google Services plugin generates `default_web_client_id`. The backend Firebase Admin configuration must use the same Firebase project.
+
+The backend must support `loginUser(idToken:)`, `signupUser(idToken:, name:)`, `refreshAccessToken`, and `logoutUser`. The Android schema matches the local backend's token-only responses. It does not require the user and favorite-team response fields from the iOS PR. Cornell email filtering is also required on the backend to enforce the restriction outside this client.
+
+The welcome screen's Sign Up and Log In buttons both start Google sign-in. The app first calls `loginUser`; only a missing-user response triggers `signupUser`. Successful authentication enters the existing app, and Sign Up Later keeps guest browsing available.
+
+`AuthRepository.state` records the backend session. A Firebase session alone does not sign the user into Score. Backend sessions are encrypted using Android Keystore and stored outside backups. Session restoration refreshes expired access tokens; network failures preserve the saved session, while rejected refresh tokens clear it.
+
+Auth is currently limited to the welcome flow. Profile screens, profile and sports onboarding, and authorization headers on the app's existing API client are not connected to it.
+
+Run `./gradlew :app:testDebugUnitTest :app:lintDebug :app:assembleDebug` with Java 17 to verify the app. End-to-end Google sign-in needs a device or emulator with Google Play services and a backend configured for the updated Firebase project.

app/build.gradle.kts

@@ -14,12 +14,12 @@ plugins {
     id("com.apollographql.apollo") version "4.0.0"
     id("kotlin-kapt")
     id("com.google.dagger.hilt.android")
-    id("org.jetbrains.kotlin.plugin.compose") version "2.0.0" // this version matches your Kotlin version
+    id("org.jetbrains.kotlin.plugin.compose") version
+        "2.0.0" // this version matches your Kotlin version
     id("org.jetbrains.kotlin.plugin.serialization")
     id("com.google.gms.google-services")
 }
 
-
 android {
     namespace = "com.cornellappdev.score"
     compileSdk = 35
@@ -38,46 +38,30 @@ android {
     }
     buildTypes {
         debug {
-            buildConfigField(
-                "String",
-                "BASE_URL",
-                "\"${secrets.getProperty("API_URL_DEV")}\""
-            )
-            buildConfigField(
-                "String",
-                "SOCKET_URL",
-                "\"${secrets.getProperty("SOCKET_URL_DEV")}\""
-            )
+            buildConfigField("String", "BASE_URL", "\"${secrets.getProperty("API_URL_DEV")}\"")
+            buildConfigField("String", "SOCKET_URL", "\"${secrets.getProperty("SOCKET_URL_DEV")}\"")
         }
         release {
-            buildConfigField(
-                "String",
-                "BASE_URL",
-                "\"${secrets.getProperty("API_URL_PROD")}\""
-            )
+            buildConfigField("String", "BASE_URL", "\"${secrets.getProperty("API_URL_PROD")}\"")
             buildConfigField(
                 "String",
                 "SOCKET_URL",
-                "\"${secrets.getProperty("SOCKET_URL_PROD")}\""
+                "\"${secrets.getProperty("SOCKET_URL_PROD")}\"",
             )
             isMinifyEnabled = false
             proguardFiles(
                 getDefaultProguardFile("proguard-android-optimize.txt"),
-                "proguard-rules.pro"
+                "proguard-rules.pro",
             )
         }
     }
-    composeOptions {
-        kotlinCompilerExtensionVersion = "1.7.0"
-    }
+    composeOptions { kotlinCompilerExtensionVersion = "1.7.0" }
 
     compileOptions {
         sourceCompatibility = JavaVersion.VERSION_1_8
         targetCompatibility = JavaVersion.VERSION_1_8
     }
-    kotlinOptions {
-        jvmTarget = "1.8"
-    }
+    kotlinOptions { jvmTarget = "1.8" }
 }
 
 dependencies {
@@ -118,16 +102,25 @@ dependencies {
     lintChecks(libs.compose.lint.checks)
     implementation(platform("com.google.firebase:firebase-bom:34.3.0"))
     implementation("com.google.firebase:firebase-analytics")
+    implementation("com.google.firebase:firebase-auth")
+    implementation("androidx.credentials:credentials:1.5.0")
+    implementation("androidx.credentials:credentials-play-services-auth:1.5.0")
+    implementation("com.google.android.libraries.identity.googleid:googleid:1.1.1")
+    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-play-services:1.10.1")
+    implementation("androidx.lifecycle:lifecycle-runtime-compose:2.8.7")
 }
 
 apollo {
     service("service") {
         packageName.set("com.example.score")
-        secrets.getProperty("API_URL_DEV")?.takeIf { it.isNotBlank() }?.let { apiUrl ->
-            introspection {
-                endpointUrl.set(apiUrl)
-                schemaFile.set(file("src/main/graphql/schema.graphqls"))
+        secrets
+            .getProperty("API_URL_DEV")
+            ?.takeIf { it.isNotBlank() }
+            ?.let { apiUrl ->
+                introspection {
+                    endpointUrl.set(apiUrl)
+                    schemaFile.set(file("src/main/graphql/schema.graphqls"))
+                }
             }
-        }
     }
 }

app/src/main/graphql/Auth.graphql

@@ -0,0 +1,25 @@
+mutation LoginUser($idToken: String!) {
+  loginUser(idToken: $idToken) {
+    accessToken
+    refreshToken
+  }
+}
+
+mutation SignupUser($idToken: String!, $name: String) {
+  signupUser(idToken: $idToken, name: $name) {
+    accessToken
+    refreshToken
+  }
+}
+
+mutation RefreshAccessToken {
+  refreshAccessToken {
+    newAccessToken
+  }
+}
+
+mutation LogoutUser {
+  logoutUser {
+    success
+  }
+}

app/src/main/graphql/schema.graphqls

@@ -223,14 +223,14 @@ type Mutation {
   createArticle(image: String, publishedAt: String!, slug: String!, sportsType: String!, title: String!, url: String!): CreateArticle
 
   """
-  Login by net_id; returns access_token and refresh_token.
+  Login with Firebase ID token; returns access_token and refresh_token.
   """
-  loginUser("User's net ID (e.g. Cornell netid)." netId: String!): LoginUser
+  loginUser("Firebase ID token from the client." idToken: String!): LoginUser
 
   """
-  Create a new user by net_id; returns access_token and refresh_token (no separate login needed).
+  Create a new user with Firebase ID token; returns access_token and refresh_token.
   """
-  signupUser("Email address." email: String, "Display name." name: String, "User's net ID (e.g. Cornell netid)." netId: String!): SignupUser
+  signupUser("Email address." email: String, "Display name." name: String, "Firebase ID token from the client." idToken: String!): SignupUser
 
   """
   Exchange a valid refresh token (in Authorization header) for a new access_token.

app/src/main/java/com/cornellappdev/score/MainActivity.kt

@@ -3,101 +3,30 @@ package com.cornellappdev.score
 import android.os.Bundle
 import androidx.activity.compose.setContent
 import androidx.activity.enableEdgeToEdge
+import androidx.activity.viewModels
 import androidx.appcompat.app.AppCompatActivity
-import androidx.compose.runtime.getValue
-import androidx.compose.runtime.mutableStateOf
-import androidx.compose.runtime.remember
-import androidx.compose.runtime.saveable.rememberSaveable
-import androidx.compose.runtime.setValue
-import androidx.core.content.edit
+import com.cornellappdev.score.auth.AuthViewModel
 import com.cornellappdev.score.model.OnboardingPreferencesRepository
-import com.cornellappdev.score.nav.root.RootNavigation
-import com.cornellappdev.score.screen.FavoriteSport
-import com.cornellappdev.score.screen.OnboardingFavoriteSportsScreen
-import com.cornellappdev.score.screen.OnboardingProfileSelectScreen
-import com.cornellappdev.score.screen.OnboardingScreen
 import com.google.firebase.Firebase
-import com.google.firebase.analytics.FirebaseAnalytics
 import com.google.firebase.analytics.analytics
 import dagger.hilt.android.AndroidEntryPoint
 import javax.inject.Inject
 
-private const val APP_PREFERENCES = "score_app_preferences"
-private const val KEY_ONBOARDING_PROFILE_PICTURE = "onboarding_profile_picture"
-private const val KEY_ONBOARDING_FAVORITE_SPORTS = "onboarding_favorite_sports"
-
-private lateinit var firebaseAnalytics: FirebaseAnalytics
-
-private enum class OnboardingStep {
-    WELCOME,
-    PROFILE_SELECT,
-    SPORT_SELECT,
-    COMPLETE
-}
-
 @AndroidEntryPoint
 class MainActivity : AppCompatActivity() {
-    @Inject
-    lateinit var onboardingPreferencesRepository: OnboardingPreferencesRepository
+    @Inject lateinit var onboardingPreferences: OnboardingPreferencesRepository
+    private val authViewModel: AuthViewModel by viewModels()
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         enableEdgeToEdge()
-
-        val onboardingCompleted = onboardingPreferencesRepository.isOnboardingCompleted()
-        val preferences = getSharedPreferences(APP_PREFERENCES, MODE_PRIVATE)
-        val savedFavoriteSportKeys = preferences
-            .getStringSet(KEY_ONBOARDING_FAVORITE_SPORTS, emptySet())
-            .orEmpty()
-            .joinToString("|")
-
+        Firebase.analytics
         setContent {
-            var onboardingStep by rememberSaveable {
-                mutableStateOf(
-                    if (onboardingCompleted) OnboardingStep.COMPLETE else OnboardingStep.WELCOME
-                )
-            }
-
-            val completeOnboarding = remember {
-                {
-                    onboardingPreferencesRepository.markOnboardingCompleted()
-                    onboardingStep = OnboardingStep.COMPLETE
-                }
-            }
-
-            when (onboardingStep) {
-                OnboardingStep.WELCOME -> OnboardingScreen(
-                    onSignUp = { onboardingStep = OnboardingStep.PROFILE_SELECT },
-                    onLogIn = completeOnboarding,
-                    onLater = completeOnboarding
-                )
-
-                OnboardingStep.PROFILE_SELECT -> OnboardingProfileSelectScreen(
-                    onNext = { selectedPicture ->
-                        preferences.edit {
-                            putString(KEY_ONBOARDING_PROFILE_PICTURE, selectedPicture.name)
-                        }
-                        onboardingStep = OnboardingStep.SPORT_SELECT
-                    }
-                )
-
-                OnboardingStep.SPORT_SELECT -> OnboardingFavoriteSportsScreen(
-                    initiallySelectedKeys = savedFavoriteSportKeys,
-                    onFinish = { selectedSports ->
-                        preferences.edit {
-                            putStringSet(
-                                KEY_ONBOARDING_FAVORITE_SPORTS,
-                                selectedSports.map(FavoriteSport::storageKey).toSet()
-                            )
-                        }
-                        completeOnboarding()
-                    }
-                )
-
-                OnboardingStep.COMPLETE -> RootNavigation()
-            }
+            ScoreApp(
+                authViewModel = authViewModel,
+                onboardingPreferences = onboardingPreferences,
+                onSignIn = { authViewModel.signIn(this) },
+            )
         }
-
-        firebaseAnalytics = Firebase.analytics
     }
 }

app/src/main/java/com/cornellappdev/score/ScoreApp.kt

@@ -0,0 +1,65 @@
+package com.cornellappdev.score
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.material3.CircularProgressIndicator
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.saveable.rememberSaveable
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import com.cornellappdev.score.auth.AuthState
+import com.cornellappdev.score.auth.AuthStatusOverlay
+import com.cornellappdev.score.auth.AuthViewModel
+import com.cornellappdev.score.model.OnboardingPreferencesRepository
+import com.cornellappdev.score.nav.root.RootNavigation
+import com.cornellappdev.score.screen.OnboardingScreen
+import com.cornellappdev.score.theme.CrimsonPrimary
+
+@Composable
+fun ScoreApp(
+    authViewModel: AuthViewModel,
+    onboardingPreferences: OnboardingPreferencesRepository,
+    onSignIn: () -> Unit,
+    modifier: Modifier = Modifier,
+) {
+    val authState by authViewModel.authState.collectAsStateWithLifecycle()
+    val signInState by authViewModel.signInState.collectAsStateWithLifecycle()
+    var skippedWelcome by rememberSaveable {
+        mutableStateOf(onboardingPreferences.isOnboardingCompleted())
+    }
+    val signedIn = authState is AuthState.SignedIn
+
+    LaunchedEffect(signedIn) {
+        if (signedIn) {
+            onboardingPreferences.markOnboardingCompleted()
+            skippedWelcome = true
+        }
+    }
+
+    Box(modifier.fillMaxSize().background(Color.White)) {
+        when {
+            authState == AuthState.Loading ->
+                Box(Modifier.fillMaxSize(), contentAlignment = Alignment.Center) {
+                    CircularProgressIndicator(color = CrimsonPrimary)
+                }
+            signedIn || skippedWelcome -> RootNavigation()
+            else ->
+                OnboardingScreen(
+                    onSignUp = onSignIn,
+                    onLogIn = onSignIn,
+                    onLater = {
+                        onboardingPreferences.markOnboardingCompleted()
+                        skippedWelcome = true
+                    },
+                )
+        }
+        AuthStatusOverlay(signInState, authViewModel::dismissError)
+    }
+}