app/src/main/java/com/bitcointxoko/gudariwallet/data/FiatRateCache.kt

@@ -1,5 +1,8 @@
 package com.bitcointxoko.gudariwallet.data
 
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
 import timber.log.Timber
 
 private const val TAG = "FiatRateCache"
@@ -13,6 +16,12 @@ private const val TAG = "FiatRateCache"
  */
 class FiatRateCache(private val fiatDataStore: FiatDataStore) {
 
+    private val _fiatFlow = MutableStateFlow<Pair<String?, Double?>>(Pair(null, null))
+
+    /** Emits the latest (currency, satsPerUnit) pair whenever [putRate] is called. */
+    val fiatFlow: StateFlow<Pair<String?, Double?>> = _fiatFlow.asStateFlow()
+
+
     // ── Rate ──────────────────────────────────────────────────────────────────
 
     private var cachedRate         : Double? = null
@@ -51,6 +60,7 @@ class FiatRateCache(private val fiatDataStore: FiatDataStore) {
         cachedRate         = rate
         rateLastFetchedAt  = now
         cachedRateCurrency = currency
+        _fiatFlow.value = Pair(currency, rate)
         fiatDataStore.persistRate(currency, rate)
         Timber.d("FIAT [RATE FRESH ] 1 $currency = $rate sats — cached + persisted")
     }
@@ -60,6 +70,7 @@ class FiatRateCache(private val fiatDataStore: FiatDataStore) {
         cachedRate         = null
         rateLastFetchedAt  = 0L
         cachedRateCurrency = ""
+        _fiatFlow.value = Pair(null, null)
     }
 
     // ── Currency list ─────────────────────────────────────────────────────────
@@ -91,6 +102,5 @@ class FiatRateCache(private val fiatDataStore: FiatDataStore) {
         Timber.d("FIAT [CURRENCIES] cached ${currencies.size} currencies")
     }
 
-    val currentRate: Double?
-        get() = cachedRate.takeIf { cachedRateCurrency.isNotBlank() }
+    val currentRate: Double? get() = cachedRate.takeIf { cachedRateCurrency.isNotBlank() }
 }

app/src/main/java/com/bitcointxoko/gudariwallet/data/PaymentFeedRepository.kt

@@ -0,0 +1,61 @@
+package com.bitcointxoko.gudariwallet.data
+
+import com.bitcointxoko.gudariwallet.data.db.ContactDao
+import com.bitcointxoko.gudariwallet.data.db.PaymentContactSummary
+import com.bitcointxoko.gudariwallet.data.db.PaymentDao
+import com.bitcointxoko.gudariwallet.data.db.toDomain
+import com.bitcointxoko.gudariwallet.data.model.ContactSummary
+import com.bitcointxoko.gudariwallet.data.model.PaymentFeedItem
+import com.bitcointxoko.gudariwallet.data.model.toPaymentFeedItem
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.combine
+
+/**
+ * Assembles the unified [PaymentFeedItem] stream by combining all four
+ * independent data sources:
+ *   1. payment_records     — via [PaymentDao.observeAll]
+ *   2. tx_contact_links    — via [ContactDao.observePaymentContactSummaries]
+ *   3. node_alias_cache    — via [NodeAliasRepository.aliases]
+ *   4. fiat rate           — via [FiatRateCache.fiatFlow]
+ *
+ * This repository does not own any of these sources — it only combines them.
+ * Filtering, searching, and sorting are the responsibility of the ViewModel.
+ */
+class PaymentFeedRepository(
+    private val paymentDao: PaymentDao,
+    private val contactDao: ContactDao,
+    private val nodeAliasRepository: NodeAliasRepository,
+    private val fiatRateCache: FiatRateCache
+) {
+
+    /**
+     * Emits a new list of [PaymentFeedItem] whenever any upstream source changes.
+     * Items are ordered newest-first (delegated to [PaymentDao.observeAll]).
+     */
+    fun observeFeedItems(): Flow<List<PaymentFeedItem>> = combine(
+        paymentDao.observeAll(),
+        contactDao.observePaymentContactSummaries(),
+        nodeAliasRepository.aliases,
+        fiatRateCache.fiatFlow
+    ) { payments, contactSummaries, aliasMap, (fiatCurrency, fiatSatsPerUnit) ->
+
+        // Group contact summaries by paymentHash for O(1) lookup per payment
+        val contactsByPayment: Map<String, List<PaymentContactSummary>> =
+            contactSummaries.groupBy { it.paymentHash }
+
+        payments.map { entity ->
+            val linked: List<ContactSummary> = contactsByPayment[entity.paymentHash]
+                ?.map { ContactSummary(id = it.contactId, displayName = it.displayName) }
+                ?: emptyList()
+
+            val resolvedAlias: String? = entity.pubkey?.let { aliasMap[it] }
+
+            entity.toDomain().toPaymentFeedItem(
+                linkedContacts = linked,
+                resolvedAlias = resolvedAlias,   // mapper falls back to entity.alias if null
+                fiatCurrency = fiatCurrency,
+                fiatSatsPerUnit = fiatSatsPerUnit
+            )
+        }
+    }
+}

app/src/main/java/com/bitcointxoko/gudariwallet/data/db/ContactDao.kt

@@ -12,6 +12,13 @@ data class ContactWithAddresses(
     val addresses: List<PaymentAddressEntity>
 )
 
+/** Flat projection used by PaymentFeedRepository to build ContactSummary lists. */
+data class PaymentContactSummary(
+    val paymentHash: String,
+    val contactId: String,
+    val displayName: String
+)
+
 @Dao
 interface ContactDao {
 
@@ -125,6 +132,17 @@ interface ContactDao {
 """)
     fun observePaymentContactNames(): Flow<List<PaymentContactName>>
 
+    // Returns all (paymentHash, contactId, displayName) triples — used by
+    // PaymentFeedRepository to build full ContactSummary lists per payment.
+    @Query("""
+    SELECT tcl.paymentHash AS paymentHash,
+           c.id AS contactId,
+           COALESCE(c.localAlias, c.displayName, c.name) AS displayName
+    FROM tx_contact_links tcl
+    INNER JOIN contacts c ON c.id = tcl.contactId
+""")
+    fun observePaymentContactSummaries(): Flow<List<PaymentContactSummary>>
+
     // For text search matching contact names — returns paymentHashes of matched payments
     @Query("""
     SELECT tcl.paymentHash FROM tx_contact_links tcl

app/src/main/java/com/bitcointxoko/gudariwallet/data/db/PaymentDao.kt

@@ -4,6 +4,8 @@ import androidx.room.Dao
 import androidx.room.Insert
 import androidx.room.OnConflictStrategy
 import androidx.room.Query
+import kotlinx.coroutines.flow.Flow
+
 @Dao
 interface PaymentDao {
 
@@ -56,6 +58,10 @@ interface PaymentDao {
     @Query("SELECT * FROM payment_records ORDER BY time DESC")
     suspend fun getAll(): List<PaymentRecordEntity>
 
+    /** Reactive version of [getAll] — emits a new list whenever any row changes. */
+    @Query("SELECT * FROM payment_records ORDER BY COALESCE(createdAt, CAST(time AS INTEGER)) DESC")
+    fun observeAll(): Flow<List<PaymentRecordEntity>>
+
     /** A single page, ordered newest-first. */
     @Query("SELECT * FROM payment_records ORDER BY time DESC LIMIT :limit OFFSET :offset")
     suspend fun getPage(limit: Int, offset: Int): List<PaymentRecordEntity>