refactor(concord): move per-relay filter assembly to shared planner

The Android assembler was hand-rolling the plane-address -> per-relay
kind-1059 RelayBasedFilter collapse (with per-relay since). That logic is
platform-agnostic — RelayBasedFilter and SincePerRelayMap are both
commons/quartz types — so lift it to ConcordSubscriptionPlanner.relayBasedFilters
alongside the existing filtersByRelay one-shot variant. The assembler now only
does the account-dependent step (deriving channel planes from folded session
state) and delegates the collapse. Covered by a new planner unit test.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CzJ2Cwo8tg4oZq43oRa3ig

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/chats/publicChannels/concord/datasource/ConcordChannelFilterAssembler.kt

@@ -26,11 +26,8 @@ import com.vitorpamplona.amethyst.commons.relayClient.composeSubscriptionManager
 import com.vitorpamplona.amethyst.model.Account
 import com.vitorpamplona.amethyst.service.relayClient.eoseManagers.PerUniqueIdEoseManager
 import com.vitorpamplona.amethyst.service.relays.SincePerRelayMap
-import com.vitorpamplona.quartz.concord.events.ConcordKinds
 import com.vitorpamplona.quartz.nip01Core.relay.client.INostrClient
 import com.vitorpamplona.quartz.nip01Core.relay.client.pool.RelayBasedFilter
-import com.vitorpamplona.quartz.nip01Core.relay.filters.Filter
-import com.vitorpamplona.quartz.nip01Core.relay.normalizer.NormalizedRelayUrl
 
 /** One screen's request to keep the user's joined Concord Channels live. */
 class ConcordChannelQueryState(
@@ -76,7 +73,9 @@ class ConcordChannelSubAssembler(
         if (entries.isEmpty()) return null
 
         // Control planes for every joined community, plus channel planes for the
-        // ones whose Control Plane has already folded.
+        // ones whose Control Plane has already folded. Deriving the channel planes
+        // is the only account-dependent step; collapsing planes into per-relay
+        // kind-1059 filters lives in the shared planner.
         val subs = ArrayList<ConcordPlaneSub>()
         subs += ConcordSubscriptionPlanner.controlPlaneSubs(entries)
         for (entry in entries) {
@@ -88,24 +87,7 @@ class ConcordChannelSubAssembler(
             subs += ConcordSubscriptionPlanner.channelPlaneSubs(entry, state)
         }
 
-        // One kind-1059 filter per host relay, carrying every plane address on it.
-        val authorsByRelay = HashMap<NormalizedRelayUrl, MutableSet<String>>()
-        for (sub in subs) {
-            for (relay in sub.relays) authorsByRelay.getOrPut(relay) { HashSet() }.add(sub.pubKeyHex)
-        }
-        if (authorsByRelay.isEmpty()) return null
-
-        return authorsByRelay.map { (relay, authors) ->
-            RelayBasedFilter(
-                relay = relay,
-                filter =
-                    Filter(
-                        kinds = listOf(ConcordKinds.WRAP),
-                        authors = authors.toList(),
-                        since = since?.get(relay)?.time,
-                    ),
-            )
-        }
+        return ConcordSubscriptionPlanner.relayBasedFilters(subs, since)
     }
 
     override fun id(key: ConcordChannelQueryState) = key.account

commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/actions/ConcordSubscriptionPlanner.kt

@@ -20,10 +20,13 @@
  */
 package com.vitorpamplona.amethyst.commons.actions
 
+import com.vitorpamplona.amethyst.commons.relays.SincePerRelayMap
 import com.vitorpamplona.quartz.concord.cord02Community.ConcordCommunityListEntry
 import com.vitorpamplona.quartz.concord.cord02Community.ConcordCommunityState
 import com.vitorpamplona.quartz.concord.cord03Channels.ConcordChannelId
+import com.vitorpamplona.quartz.concord.events.ConcordKinds
 import com.vitorpamplona.quartz.nip01Core.core.hexToByteArray
+import com.vitorpamplona.quartz.nip01Core.relay.client.pool.RelayBasedFilter
 import com.vitorpamplona.quartz.nip01Core.relay.filters.Filter
 import com.vitorpamplona.quartz.nip01Core.relay.normalizer.NormalizedRelayUrl
 import com.vitorpamplona.quartz.nip01Core.relay.normalizer.RelayUrlNormalizer
@@ -89,5 +92,37 @@ object ConcordSubscriptionPlanner {
         return authorsByRelay.mapValues { (_, authors) -> listOf(ConcordActions.planeFilterFor(authors)) }
     }
 
+    /**
+     * Collapses [subs] into one [RelayBasedFilter] per host relay for a live
+     * subscription: each relay gets a single `{kinds:[1059], authors:[…all plane
+     * pks on it…], since}` filter, with [since] applied per relay from the EOSE
+     * map. Returns null when no plane resolves to a relay (nothing to subscribe).
+     *
+     * This is the assembler-facing shape (what a `PerUniqueIdEoseManager` returns);
+     * [filtersByRelay] is the one-shot drain shape (no `since`).
+     */
+    fun relayBasedFilters(
+        subs: List<ConcordPlaneSub>,
+        since: SincePerRelayMap?,
+    ): List<RelayBasedFilter>? {
+        val authorsByRelay = HashMap<NormalizedRelayUrl, MutableSet<String>>()
+        for (sub in subs) {
+            for (relay in sub.relays) authorsByRelay.getOrPut(relay) { HashSet() }.add(sub.pubKeyHex)
+        }
+        if (authorsByRelay.isEmpty()) return null
+
+        return authorsByRelay.map { (relay, authors) ->
+            RelayBasedFilter(
+                relay = relay,
+                filter =
+                    Filter(
+                        kinds = listOf(ConcordKinds.WRAP),
+                        authors = authors.toList(),
+                        since = since?.get(relay)?.time,
+                    ),
+            )
+        }
+    }
+
     private fun normalize(urls: List<String>): Set<NormalizedRelayUrl> = urls.mapNotNullTo(mutableSetOf()) { RelayUrlNormalizer.normalizeOrNull(it) }
 }

commons/src/commonTest/kotlin/com/vitorpamplona/amethyst/commons/actions/ConcordSubscriptionPlannerTest.kt

@@ -20,13 +20,16 @@
  */
 package com.vitorpamplona.amethyst.commons.actions
 
+import com.vitorpamplona.amethyst.commons.relays.MutableTime
 import com.vitorpamplona.quartz.concord.cord02Community.ConcordCommunityFactory
 import com.vitorpamplona.quartz.nip01Core.core.toHexKey
 import com.vitorpamplona.quartz.nip01Core.crypto.KeyPair
+import com.vitorpamplona.quartz.nip01Core.relay.normalizer.RelayUrlNormalizer
 import com.vitorpamplona.quartz.nip01Core.signers.NostrSignerInternal
 import kotlinx.coroutines.test.runTest
 import kotlin.test.Test
 import kotlin.test.assertEquals
+import kotlin.test.assertNull
 import kotlin.test.assertTrue
 
 class ConcordSubscriptionPlannerTest {
@@ -71,4 +74,33 @@ class ConcordSubscriptionPlannerTest {
             assertTrue(filter.authors!!.contains(community.controlPlane.publicKeyHex))
             assertTrue(filter.authors!!.contains(general.pubKeyHex))
         }
+
+    @Test
+    fun relayBasedFiltersCollapsePerRelayAndApplySince() =
+        runTest {
+            val community = ConcordCommunityFactory.create(owner, "Nostrichs", createdAt = 1L, relays = listOf("wss://r.example"))
+            val entry =
+                com.vitorpamplona.quartz.concord.cord02Community.ConcordCommunityListEntry(
+                    id = community.communityIdHex,
+                    owner = community.ownerPubKey,
+                    ownerSalt = community.ownerSalt.toHexKey(),
+                    root = community.communityRoot.toHexKey(),
+                    rootEpoch = community.rootEpoch,
+                    relays = listOf("wss://r.example"),
+                    name = "Nostrichs",
+                )
+            val subs = ConcordSubscriptionPlanner.controlPlaneSubs(listOf(entry))
+            val relay = RelayUrlNormalizer.normalizeOrNull("wss://r.example")!!
+
+            // One kind-1059 filter for the single relay, carrying the derived since.
+            val filters = ConcordSubscriptionPlanner.relayBasedFilters(subs, mutableMapOf(relay to MutableTime(1234L)))!!
+            assertEquals(1, filters.size)
+            assertEquals(relay, filters[0].relay)
+            assertEquals(listOf(1059), filters[0].filter.kinds)
+            assertEquals(1234L, filters[0].filter.since)
+            assertTrue(filters[0].filter.authors!!.contains(community.controlPlane.publicKeyHex))
+
+            // No planes resolve to a relay -> nothing to subscribe.
+            assertNull(ConcordSubscriptionPlanner.relayBasedFilters(emptyList(), null))
+        }
 }