refactor: centralize all Firestore collection paths in FirestoreCollections constants

app/src/main/java/app/closer/core/billing/FirestoreEntitlementChecker.kt

@@ -1,5 +1,6 @@
 package app.closer.core.billing
 
+import app.closer.data.remote.FirestoreCollections
 import app.closer.domain.model.AuthState
 import app.closer.domain.repository.AuthRepository
 import com.google.firebase.firestore.DocumentSnapshot
@@ -125,7 +126,9 @@ class FirestoreEntitlementChecker @Inject constructor(
     }
 
     private fun entitlementsRef(userId: String) =
-        firestore.collection("users").document(userId).collection("entitlements").document("premium")
+        firestore.collection(FirestoreCollections.USERS).document(userId)
+            .collection(FirestoreCollections.Users.ENTITLEMENTS)
+            .document(FirestoreCollections.Users.ENTITLEMENT_PREMIUM_DOC)
 
     companion object {
         private const val PREMIUM_ENTITLEMENT_ID = "closer_premium"

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

@@ -26,7 +26,8 @@ class FirestoreBucketListDataSource @Inject constructor() {
 
     private val db = FirebaseFirestore.getInstance()
     private fun itemsRef(coupleId: String) =
-        db.collection("couples").document(coupleId).collection("bucket_list")
+        db.collection(FirestoreCollections.COUPLES).document(coupleId)
+            .collection(FirestoreCollections.Couples.BUCKET_LIST)
 
     // ─── CRUD methods ────────────────────────────────────────────────────────
 

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

@@ -0,0 +1,40 @@
+package app.closer.data.remote
+
+/**
+ * Single source of truth for all Firestore collection and fixed document-ID names.
+ *
+ * Use these constants everywhere instead of inline string literals so that a path
+ * rename requires a change in exactly one place and the compiler catches every caller.
+ */
+object FirestoreCollections {
+
+    // ── Top-level collections ─────────────────────────────────────────────────
+    const val USERS = "users"
+    const val COUPLES = "couples"
+    const val INVITES = "invites"
+
+    // ── Subcollections under users/{uid} ──────────────────────────────────────
+    object Users {
+        const val ENTITLEMENTS = "entitlements"
+        const val FCM_TOKENS = "fcmTokens"
+        const val ENTITLEMENT_PREMIUM_DOC = "premium"
+    }
+
+    // ── Subcollections under couples/{coupleId} ───────────────────────────────
+    object Couples {
+        const val SESSIONS = "sessions"
+        const val QUESTION_THREADS = "question_threads"
+        const val DATE_SWIPES = "date_swipes"
+        const val DATE_MATCHES = "date_matches"
+        const val DATE_PLAN_PREFERENCES = "date_plan_preferences"
+        const val DATE_PLANS = "date_plans"
+        const val BUCKET_LIST = "bucket_list"
+    }
+
+    // ── Subcollections under …/question_threads/{threadId} ────────────────────
+    object QuestionThreads {
+        const val ANSWERS = "answers"
+        const val MESSAGES = "messages"
+        const val REACTIONS = "reactions"
+    }
+}

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

@@ -15,8 +15,8 @@ import kotlin.coroutines.resumeWithException
 class FirestoreCoupleDataSource @Inject constructor() {
 
     private val db = FirebaseFirestore.getInstance()
-    private fun coupleRef(coupleId: String) = db.collection("couples").document(coupleId)
+    private fun coupleRef(coupleId: String) = db.collection(FirestoreCollections.COUPLES).document(coupleId)
-    private fun userRef(uid: String) = db.collection("users").document(uid)
+    private fun userRef(uid: String) = db.collection(FirestoreCollections.USERS).document(uid)
 
     suspend fun createCouple(inviterUserId: String, acceptorUserId: String, inviteCode: String): String {
         val coupleId = UUID.randomUUID().toString()
@@ -89,7 +89,7 @@ class FirestoreCoupleDataSource @Inject constructor() {
 
     suspend fun leaveCouple(userId: String) {
         val userSnap = suspendCancellableCoroutine<DocumentSnapshot> { cont ->
-            db.collection("users").document(userId).get()
+            userRef(userId).get()
                 .addOnSuccessListener { cont.resume(it) }
                 .addOnFailureListener { cont.resumeWithException(it) }
         }
@@ -104,7 +104,7 @@ class FirestoreCoupleDataSource @Inject constructor() {
         suspendCancellableCoroutine<Unit> { cont ->
             val batch = db.batch()
             allUserIds.forEach { uid ->
-                batch.update(db.collection("users").document(uid), "coupleId", null)
+                batch.update(userRef(uid), "coupleId", null)
             }
             batch.commit()
                 .addOnSuccessListener { cont.resume(Unit) }

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

@@ -36,7 +36,8 @@ class FirestoreDateMatchDataSource @Inject constructor() {
 
     private val db = FirebaseFirestore.getInstance()
     private fun matchesRef(coupleId: String) =
-        db.collection("couples").document(coupleId).collection("date_matches")
+        db.collection(FirestoreCollections.COUPLES).document(coupleId)
+            .collection(FirestoreCollections.Couples.DATE_MATCHES)
 
     suspend fun createMatch(coupleId: String, dateIdeaId: String, matchedBy: List<String>): String {
         val doc = matchesRef(coupleId).document()

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

@@ -29,10 +29,12 @@ class FirestoreDatePlanDataSource @Inject constructor() {
 
     private val db = FirebaseFirestore.getInstance()
     private fun preferencesRef(coupleId: String) =
-        db.collection("couples").document(coupleId).collection("date_plan_preferences")
+        db.collection(FirestoreCollections.COUPLES).document(coupleId)
+            .collection(FirestoreCollections.Couples.DATE_PLAN_PREFERENCES)
 
     private fun plansRef(coupleId: String) =
-        db.collection("couples").document(coupleId).collection("date_plans")
+        db.collection(FirestoreCollections.COUPLES).document(coupleId)
+            .collection(FirestoreCollections.Couples.DATE_PLANS)
 
     // ─── Preference methods ──────────────────────────────────────────────────
 

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

@@ -37,7 +37,8 @@ class FirestoreDateSwipeDataSource @Inject constructor() {
 
     private val db = FirebaseFirestore.getInstance()
     private fun swipesRef(coupleId: String) =
-        db.collection("couples").document(coupleId).collection("date_swipes")
+        db.collection(FirestoreCollections.COUPLES).document(coupleId)
+            .collection(FirestoreCollections.Couples.DATE_SWIPES)
 
     suspend fun recordSwipe(coupleId: String, swipe: DateSwipe) {
         val path = swipesRef(coupleId).document(swipe.dateIdeaId)

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

@@ -14,7 +14,7 @@ import kotlin.random.Random
 class FirestoreInviteDataSource @Inject constructor() {
 
     private val db = FirebaseFirestore.getInstance()
-    private fun inviteRef(code: String) = db.collection("invites").document(code)
+    private fun inviteRef(code: String) = db.collection(FirestoreCollections.INVITES).document(code)
 
     fun generateCode(): String = (1..6)
         .map { CODE_CHARS[Random.nextInt(CODE_CHARS.length)] }

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

@@ -24,7 +24,8 @@ class FirestoreQuestionThreadDataSource @Inject constructor() {
     private val db = FirebaseFirestore.getInstance()
 
     private fun threadsRef(coupleId: String) =
-        db.collection("couples").document(coupleId).collection("question_threads")
+        db.collection(FirestoreCollections.COUPLES).document(coupleId)
+            .collection(FirestoreCollections.Couples.QUESTION_THREADS)
 
     // ─── Thread ─────────────────────────────────────────────────────────────────
 
@@ -77,7 +78,7 @@ class FirestoreQuestionThreadDataSource @Inject constructor() {
         val now = FieldValue.serverTimestamp()
         threadsRef(coupleId)
             .document(threadId)
-            .collection("answers")
+            .collection(FirestoreCollections.QuestionThreads.ANSWERS)
             .document(userId)
             .set(
                 mapOf(
@@ -96,7 +97,7 @@ class FirestoreQuestionThreadDataSource @Inject constructor() {
     suspend fun getAnswerCount(coupleId: String, threadId: String): Int {
         val snap = threadsRef(coupleId)
             .document(threadId)
-            .collection("answers")
+            .collection(FirestoreCollections.QuestionThreads.ANSWERS)
             .getAwait()
         return snap.size()
     }
@@ -104,7 +105,7 @@ class FirestoreQuestionThreadDataSource @Inject constructor() {
     fun observeAnswers(coupleId: String, threadId: String): Flow<List<QuestionAnswer>> = callbackFlow {
         val listener = threadsRef(coupleId)
             .document(threadId)
-            .collection("answers")
+            .collection(FirestoreCollections.QuestionThreads.ANSWERS)
             .addSnapshotListener { snap, err ->
                 if (err != null || snap == null) return@addSnapshotListener
                 trySend(snap.documents.mapNotNull { it.toQuestionAnswer() })
@@ -117,7 +118,7 @@ class FirestoreQuestionThreadDataSource @Inject constructor() {
     suspend fun sendMessage(coupleId: String, threadId: String, message: QuestionMessage) {
         threadsRef(coupleId)
             .document(threadId)
-            .collection("messages")
+            .collection(FirestoreCollections.QuestionThreads.MESSAGES)
             .add(
                 mapOf(
                     "userId" to message.userId,
@@ -130,7 +131,7 @@ class FirestoreQuestionThreadDataSource @Inject constructor() {
     fun observeMessages(coupleId: String, threadId: String): Flow<List<QuestionMessage>> = callbackFlow {
         val listener = threadsRef(coupleId)
             .document(threadId)
-            .collection("messages")
+            .collection(FirestoreCollections.QuestionThreads.MESSAGES)
             .orderBy("createdAt", Query.Direction.ASCENDING)
             .addSnapshotListener { snap, err ->
                 if (err != null || snap == null) return@addSnapshotListener
@@ -145,7 +146,7 @@ class FirestoreQuestionThreadDataSource @Inject constructor() {
         val docId = "${reaction.userId}_${reaction.targetUserId}"
         threadsRef(coupleId)
             .document(threadId)
-            .collection("reactions")
+            .collection(FirestoreCollections.QuestionThreads.REACTIONS)
             .document(docId)
             .set(
                 mapOf(
@@ -160,7 +161,7 @@ class FirestoreQuestionThreadDataSource @Inject constructor() {
     fun observeReactions(coupleId: String, threadId: String): Flow<List<QuestionReaction>> = callbackFlow {
         val listener = threadsRef(coupleId)
             .document(threadId)
-            .collection("reactions")
+            .collection(FirestoreCollections.QuestionThreads.REACTIONS)
             .addSnapshotListener { snap, err ->
                 if (err != null || snap == null) return@addSnapshotListener
                 trySend(snap.documents.mapNotNull { it.toQuestionReaction() })

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

@@ -14,7 +14,7 @@ import kotlin.coroutines.resumeWithException
 class FirestoreUserDataSource @Inject constructor() {
 
     private val db = FirebaseFirestore.getInstance()
-    private fun userRef(uid: String) = db.collection("users").document(uid)
+    private fun userRef(uid: String) = db.collection(FirestoreCollections.USERS).document(uid)
 
     suspend fun getUser(uid: String): User? =
         suspendCancellableCoroutine { cont ->
@@ -89,7 +89,7 @@ class FirestoreUserDataSource @Inject constructor() {
         token: String,
         metadata: DeviceMetadata
     ): Unit = suspendCancellableCoroutine { cont ->
-        userRef(uid).collection("fcmTokens").document(token)
+        userRef(uid).collection(FirestoreCollections.Users.FCM_TOKENS).document(token)
             .set(
                 mapOf(
                     "token" to token,

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

@@ -1,5 +1,6 @@
 package app.closer.data.repository
 
+import app.closer.data.remote.FirestoreCollections
 import app.closer.domain.model.QuestionSession
 import app.closer.domain.repository.QuestionSessionRepository
 import com.google.firebase.firestore.FirebaseFirestore
@@ -14,14 +15,14 @@ class QuestionSessionRepositoryImpl @Inject constructor(
 
     override suspend fun saveSession(session: QuestionSession): Result<Unit> = runCatching {
         val doc = if (session.id.isBlank()) {
-            firestore.collection("couples")
+            firestore.collection(FirestoreCollections.COUPLES)
                 .document(session.coupleId)
-                .collection("sessions")
+                .collection(FirestoreCollections.Couples.SESSIONS)
                 .document()
         } else {
-            firestore.collection("couples")
+            firestore.collection(FirestoreCollections.COUPLES)
                 .document(session.coupleId)
-                .collection("sessions")
+                .collection(FirestoreCollections.Couples.SESSIONS)
                 .document(session.id)
         }
 
@@ -41,9 +42,9 @@ class QuestionSessionRepositoryImpl @Inject constructor(
 
     override suspend fun getSessionsForCouple(coupleId: String): Result<List<QuestionSession>> =
         runCatching {
-            firestore.collection("couples")
+            firestore.collection(FirestoreCollections.COUPLES)
                 .document(coupleId)
-                .collection("sessions")
+                .collection(FirestoreCollections.Couples.SESSIONS)
                 .orderBy("completedAt", com.google.firebase.firestore.Query.Direction.DESCENDING)
                 .limit(50)
                 .get()