.gitignore

@@ -28,6 +28,7 @@ node_modules/
 .pnpm-store/
 build/
 .svelte-kit/
+.next/
 
 # Rust/Tauri
 *target/

src/app/core/sync.ts

@@ -1,8 +1,9 @@
 import {page} from "$app/stores"
 import type {Unsubscriber} from "svelte/store"
-import {derived, get} from "svelte/store"
-import {last, call, ifLet, assoc, chunk, sleep, identity, WEEK, ago} from "@welshman/lib"
+import {get} from "svelte/store"
+import {last, call, ifLet, assoc, chunk, sleep, WEEK, ago} from "@welshman/lib"
 import {PollResponse} from "nostr-tools/kinds"
+import {merged} from "@welshman/store"
 import {
   getListTags,
   getRelayTagValues,
@@ -21,7 +22,7 @@ import {
   unionFilters,
   getTagValue,
 } from "@welshman/util"
-import type {Filter, TrustedEvent} from "@welshman/util"
+import type {Filter, List, PublishedList, TrustedEvent} from "@welshman/util"
 import {request, requestOne, Difference, DifferenceEvent} from "@welshman/net"
 import {
   pubkey,
@@ -74,6 +75,8 @@ const pullOneWithFallback = async (
   signal: AbortSignal,
   onEvent?: (event: TrustedEvent) => void,
 ) => {
+  if (signal.aborted) return
+
   const cachedEvents = repository.query([filter]).filter(isSignedEvent)
   const since = last(cachedEvents.slice(10))?.created_at || 0
 
@@ -86,6 +89,12 @@ const pullOneWithFallback = async (
   const shouldFallback =
     !hasNegentropy(url) ||
     (await new Promise(resolve => {
+      if (signal.aborted) {
+        resolve(false)
+        return
+      }
+
+      // If teardown wins while the diff is opening, skip the fallback path and let cleanup stay in control.
       const diff = new Difference({relay: url, filter, events: cachedEvents, signal})
 
       diff.on(DifferenceEvent.Error, () => {
@@ -111,9 +120,7 @@ export const pullWithFallback = async ({url, signal, filters, onEvent}: SyncOpts
 
   if (signal.aborted) return
 
-  for (const filter of filters) {
-    pullOneWithFallback(url, filter, signal, onEvent)
-  }
+  await Promise.all(filters.map(filter => pullOneWithFallback(url, filter, signal, onEvent)))
 }
 
 const listen = ({url, signal, filters, onEvent}: SyncOpts) => {
@@ -123,6 +130,8 @@ const listen = ({url, signal, filters, onEvent}: SyncOpts) => {
 }
 
 const pullAndListen = (options: SyncOpts) => {
+  if (options.signal.aborted) return
+
   pullWithFallback(options)
   listen(options)
 }
@@ -197,7 +206,7 @@ const syncUserRoomMembership = (url: string, h: string) => {
 const syncUserData = () => {
   const unsubscribersByKey = new Map<string, Unsubscriber>()
 
-  const unsubscribeGroupList = userGroupList.subscribe($userGroupList => {
+  const syncGroupList = ($userGroupList: List | undefined) => {
     if ($userGroupList) {
       const keys = new Set<string>()
 
@@ -226,26 +235,32 @@ const syncUserData = () => {
         }
       }
     }
-  })
+  }
 
-  const unsubscribeRelayList = userRelayList.subscribe($userRelayList => {
-    if ($userRelayList) {
-      loadBlossomServerList($userRelayList.event.pubkey)
-      loadBlockedRelayList($userRelayList.event.pubkey)
-      loadFollowList($userRelayList.event.pubkey)
-      loadGroupList($userRelayList.event.pubkey)
-      loadMuteList($userRelayList.event.pubkey)
-      loadProfile($userRelayList.event.pubkey)
-      loadSettings($userRelayList.event.pubkey)
-      loadFeedsForPubkey($userRelayList.event.pubkey)
-    }
-  })
+  const syncRelayList = ($userRelayList: PublishedList | undefined) => {
+    const pubkey = $userRelayList?.event?.pubkey
 
-  const unsubscribeFollows = userFollowList.subscribe(async $userFollowList => {
+    if (!pubkey) return
+
+    loadBlossomServerList(pubkey)
+    loadBlockedRelayList(pubkey)
+    loadFollowList(pubkey)
+    loadGroupList(pubkey)
+    loadMuteList(pubkey)
+    loadProfile(pubkey)
+    loadSettings(pubkey)
+    loadFeedsForPubkey(pubkey)
+  }
+
+  const syncFollowList = async (signal: AbortSignal) => {
     for (const pubkeys of chunk(10, get(bootstrapPubkeys))) {
+      if (signal.aborted) return
+
       // This isn't urgent, avoid clogging other stuff up
       await sleep(1000)
 
+      if (signal.aborted) return
+
       await Promise.all(
         pubkeys.flatMap(pk => [
           loadRelayList(pk),
@@ -256,9 +271,26 @@ const syncUserData = () => {
         ]),
       )
     }
+  }
+
+  let bootstrapFollowController = new AbortController()
+
+  const unsubscribeGroupList = merged([userGroupList]).subscribe(([$userGroupList]) => {
+    syncGroupList($userGroupList)
+  })
+
+  const unsubscribeRelayList = merged([userRelayList]).subscribe(([$userRelayList]) => {
+    syncRelayList($userRelayList)
+  })
+
+  const unsubscribeFollows = merged([userFollowList]).subscribe(() => {
+    bootstrapFollowController.abort()
+    bootstrapFollowController = new AbortController()
+    void syncFollowList(bootstrapFollowController.signal)
   })
 
   return () => {
+    bootstrapFollowController.abort()
     unsubscribersByKey.forEach(call)
     unsubscribeGroupList()
     unsubscribeRelayList()
@@ -321,7 +353,7 @@ const syncSpace = (url: string, rooms: string[]) => {
 }
 
 const syncSpaces = () => {
-  const store = derived([userGroupList, page], identity)
+  const store = merged([userGroupList, page])
   const unsubscribersByUrl = new Map<string, Unsubscriber>()
   const roomsByUrl = new Map<string, string>()
 
@@ -383,6 +415,7 @@ const syncDMs = () => {
   const unsubscribersByUrl = new Map<string, Unsubscriber>()
 
   let currentPubkey: string | undefined
+  let currentShouldUnwrap = false
 
   const unsubscribeAll = () => {
     for (const [url, unsubscribe] of unsubscribersByUrl.entries()) {
@@ -391,6 +424,34 @@ const syncDMs = () => {
     }
   }
 
+  const syncPubkey = ($pubkey: string | undefined, $shouldUnwrap: boolean) => {
+    if ($pubkey !== currentPubkey) {
+      unsubscribeAll()
+    }
+
+    if ($pubkey && $shouldUnwrap) {
+      loadRelayList($pubkey)
+        .then(() => loadMessagingRelayList($pubkey))
+        .then($l => {
+          if ($l && currentPubkey === $pubkey && currentShouldUnwrap === $shouldUnwrap) {
+            subscribeAll($pubkey, getRelayTagValues(getListTags($l)))
+          }
+        })
+    }
+
+    currentPubkey = $pubkey
+    currentShouldUnwrap = $shouldUnwrap
+  }
+
+  const syncList = ($userMessagingRelayList: List | undefined) => {
+    const $pubkey = pubkey.get()
+    const $shouldUnwrap = shouldUnwrap.get()
+
+    if ($pubkey && $shouldUnwrap) {
+      subscribeAll($pubkey, getRelayTagValues(getListTags($userMessagingRelayList)))
+    }
+  }
+
   const subscribeAll = (pubkey: string, urls: string[]) => {
     // Start syncing newly added relays
     for (const url of urls) {
@@ -408,33 +469,16 @@ const syncDMs = () => {
     }
   }
 
-  // When pubkey changes, re-sync
-  const unsubscribePubkey = derived([pubkey, shouldUnwrap], identity).subscribe(
-    ([$pubkey, $shouldUnwrap]) => {
-      if ($pubkey !== currentPubkey) {
-        unsubscribeAll()
-      }
-
-      // If we have a pubkey, refresh our user's relay list then sync our subscriptions
-      if ($pubkey && $shouldUnwrap) {
-        loadRelayList($pubkey)
-          .then(() => loadMessagingRelayList($pubkey))
-          .then($l => subscribeAll($pubkey, getRelayTagValues(getListTags($l))))
-      }
-
-      currentPubkey = $pubkey
-    },
-  )
+  const unsubscribePubkey = merged([pubkey, shouldUnwrap]).subscribe(([$pubkey, $shouldUnwrap]) => {
+    syncPubkey($pubkey, $shouldUnwrap)
+  })
 
   // When user messaging relays change, update synchronization
-  const unsubscribeList = userMessagingRelayList.subscribe($userMessagingRelayList => {
-    const $pubkey = pubkey.get()
-    const $shouldUnwrap = shouldUnwrap.get()
-
-    if ($pubkey && $shouldUnwrap) {
-      subscribeAll($pubkey, getRelayTagValues(getListTags($userMessagingRelayList)))
-    }
-  })
+  const unsubscribeList = merged([userMessagingRelayList]).subscribe(
+    ([$userMessagingRelayList]) => {
+      syncList($userMessagingRelayList)
+    },
+  )
 
   return () => {
     unsubscribeAll()