initial useQuery proxy implementation

Author: afbase

src/state/queries/microcosm-fallback.ts

@@ -0,0 +1,226 @@
+import {AtUri} from '@atproto/api'
+import type {AppBskyFeedPost, AppBskyActorProfile} from '@atproto/api'
+
+const SLINGSHOT_URL = 'https://slingshot.microcosm.blue'
+const CONSTELLATION_URL = 'https://constellation.microcosm.blue'
+
+export interface MicrocosmRecord {
+    uri: string
+    cid: string
+    value: any
+}
+
+export interface ConstellationCounts {
+    likeCount: number
+    repostCount: number
+    replyCount: number
+    // might need a saves/bookmark counter
+    // bookmarkCount: number
+}
+
+/**
+ * Generic helper to fetch from Slingshot proxy
+ */
+async function fetchFromSlingshot<T>(
+  endpoint: string,
+  params: Record<string, string>
+): Promise<T | null> {
+  try {
+    const queryString = new URLSearchParams(
+      Object.entries(params).map(([key, value]) => [key, encodeURIComponent(value)])
+    ).toString()
+    
+    const res = await fetch(`${SLINGSHOT_URL}/xrpc/${endpoint}?${queryString}`)
+    if (!res.ok) return null
+    return await res.json()
+  } catch (e) {
+    console.error(`Slingshot fetch failed (${endpoint}):`, e)
+    return null
+  }
+}
+
+/**
+ * Fetch a record directly from PDS via Slingshot proxy
+ */
+export async function fetchRecordViaSlingshot(
+  atUri: string
+): Promise<MicrocosmRecord | null> {
+  return fetchFromSlingshot<MicrocosmRecord>(
+    'com.bad-example.repo.getUriRecord',
+    { at_uri: atUri }
+  )
+}
+
+/**
+ * Resolve identity (DID/handle) via Slingshot
+ */
+export async function resolveIdentityViaSlingshot(
+  identifier: string
+): Promise<{did: string; handle: string; pds: string} | null> {
+  return fetchFromSlingshot(
+    'com.bad-example.identity.resolveMiniDoc',
+    { identifier }
+  )
+}
+
+export async function fetchConstellationCounts(
+    atUri: string
+): Promise<ConstellationCounts> {
+    try {
+    const res = await fetch(
+    `${CONSTELLATION_URL}/links/all?target=${encodeURIComponent(atUri)}`
+    )
+    if (!res.ok) throw new Error('Constellation fetch failed')
+
+    const data = await res.json()
+    const links = data.links || {}
+
+    return {
+      likeCount: links?.['app.bsky.feed.like']?.['.subject.uri']?.distinct_dids ?? 0,
+      repostCount: links?.['app.bsky.feed.repost']?.['.subject.uri']?.distinct_dids ?? 0,
+      replyCount: links?.['app.bsky.feed.post']?.['.reply.parent.uri']?.records ?? 0,
+    }
+  } catch (e) {
+    console.error('Constellation fetch failed:', e)
+    return {likeCount: 0, repostCount: 0, replyCount: 0}
+  }
+}
+
+/**
+ * Detect if error is AppView-related (suspended user, not found, etc.)
+ */
+export function isAppViewError(error: any): boolean {
+  if (!error) return false
+
+  // Check HTTP status codes
+  if (error.status === 400 || error.status === 404) return true
+
+  // Check error messages
+  // TODO: see if there is an easy way to source error messages from the appview
+  const msg = error.message?.toLowerCase() || ''
+  if (msg.includes('not found')) return true
+  if (msg.includes('suspended')) return true
+  if (msg.includes('could not locate')) return true
+
+  return false
+}
+
+/**
+ * Build synthetic ProfileViewDetailed from PDS data
+ */
+export async function buildSyntheticProfileView(
+  did: string,
+  handle: string
+): Promise<any> {
+  const profileUri = `at://${did}/app.bsky.actor.profile/self`
+  const record = await fetchRecordViaSlingshot(profileUri)
+
+  return {
+    $type: 'app.bsky.actor.defs#profileViewDetailed',
+    did,
+    handle,
+    displayName: record?.value?.displayName || handle,
+    description: record?.value?.description || '',
+    avatar: record?.value?.avatar
+      ? `https://cdn.bsky.app/img/avatar/plain/${did}/${record.value.avatar.ref.$link}@jpeg`
+      : undefined,
+    banner: record?.value?.banner
+      ? `https://cdn.bsky.app/img/banner/plain/${did}/${record.value.banner.ref.$link}@jpeg`
+      : undefined,
+    followersCount: undefined, // Not available from PDS
+    followsCount: undefined,   // Not available from PDS
+    postsCount: undefined,     // Not available from PDS
+    indexedAt: new Date().toISOString(),
+    viewer: {},
+    labels: [],
+    __fallbackMode: true, // Mark as fallback data
+  }
+}
+
+/**
+ * Build synthetic PostView from PDS + Constellation data
+ */
+export async function buildSyntheticPostView(
+  atUri: string,
+  authorDid: string,
+  authorHandle: string
+): Promise<any> {
+  const record = await fetchRecordViaSlingshot(atUri)
+  if (!record) return null
+
+  const counts = await fetchConstellationCounts(atUri)
+  const profileView = await buildSyntheticProfileView(authorDid, authorHandle)
+
+  return {
+    $type: 'app.bsky.feed.defs#postView',
+    uri: atUri,
+    cid: record.cid,
+    author: profileView,
+    record: record.value,
+    indexedAt: new Date().toISOString(),
+    likeCount: counts.likeCount,
+    repostCount: counts.repostCount,
+    replyCount: counts.replyCount,
+    viewer: {},
+    labels: [],
+    __fallbackMode: true, // Mark as fallback data
+  }
+}
+
+/**
+ * Build synthetic feed page from PDS data
+ * This is used for infinite queries that need paginated results
+ */
+export async function buildSyntheticFeedPage(
+  did: string,
+  pdsUrl: string,
+  cursor?: string
+): Promise<any> {
+  try {
+    const limit = 25
+    const cursorParam = cursor ? `&cursor=${encodeURIComponent(cursor)}` : ''
+
+    // Fetch posts directly from PDS using com.atproto.repo.listRecords
+    const url = `${pdsUrl}/xrpc/com.atproto.repo.listRecords?repo=${did}&collection=app.bsky.feed.post&limit=${limit}${cursorParam}`
+    const res = await fetch(url)
+
+    if (!res.ok) {
+      console.error('[Fallback] Failed to fetch author feed from PDS:', res.statusText)
+      return null
+    }
+
+    const data = await res.json()
+
+    // Build FeedViewPost array from records
+    const feed = await Promise.all(
+      data.records.map(async (record: any) => {
+        const postView = await buildSyntheticPostView(
+          record.uri,
+          did,
+          '' // Handle will be resolved in buildSyntheticPostView
+        )
+
+        if (!postView) return null
+
+        // Wrap in FeedViewPost format
+        return {
+          $type: 'app.bsky.feed.defs#feedViewPost',
+          post: postView,
+          feedContext: undefined,
+        }
+      })
+    )
+
+    // Filter out null results
+    const validFeed = feed.filter(item => item !== null)
+
+    return {
+      feed: validFeed,
+      cursor: data.cursor,
+      __fallbackMode: true, // Mark as fallback data
+    }
+  } catch (e) {
+    console.error('[Fallback] Failed to build synthetic feed page:', e)
+    return null
+  }
+}