feat: add blog post composables

These composables will be used in this PR #257.

Co-authored-by: Brandon Hurrington <brandon.o.hurrington@gmail.com>

Author: jonathanyeong

app/composables/useAuthorProfiles.ts

@@ -0,0 +1,30 @@
+import type { Author, ResolvedAuthor } from '#shared/schemas/blog'
+
+/**
+ * @public
+ */
+export function useAuthorProfiles(authors: Author[]) {
+  const authorsJson = JSON.stringify(authors)
+
+  const { data } = useFetch('/api/atproto/author-profiles', {
+    query: {
+      authors: authorsJson,
+    },
+  })
+
+  const resolvedAuthors = computed<ResolvedAuthor[]>(
+    () =>
+      data.value?.authors ??
+      authors.map(author => ({
+        ...author,
+        avatar: null,
+        profileUrl: author.blueskyHandle
+          ? `https://bsky.app/profile/${author.blueskyHandle}`
+          : null,
+      })),
+  )
+
+  return {
+    resolvedAuthors,
+  }
+}

app/composables/useBlogPostBlueskyLink.ts

@@ -0,0 +1,92 @@
+import { Constellation } from '#shared/utils/constellation'
+import { NPMX_SITE } from '#shared/utils/constants'
+
+const BLOG_BACKLINK_TTL_IN_SECONDS = 60 * 5
+
+// TODO: Remove did when going live
+const TESTING_ROE_DID = 'did:plc:jbeaa5kdaladzwq3r7f5xgwe'
+// const TESTING_BACKLINK_URL = 'https://roe.dev/blog/the-golden-thread'
+// const NPMX_DID = 'did:plc:u5zp7npt5kpueado77kuihyz'
+
+/**
+ * @public
+ */
+export interface BlogPostBlueskyLink {
+  did: string
+  rkey: string
+  postUri: string
+}
+
+/**
+ * @public
+ */
+export function useBlogPostBlueskyLink(slug: MaybeRefOrGetter<string | null | undefined>) {
+  const cachedFetch = useCachedFetch()
+
+  const blogUrl = computed(() => {
+    const s = toValue(slug)
+    if (!s) return null
+    return `${NPMX_SITE}/blog/${s}`
+    // return TESTING_BACKLINK_URL
+  })
+
+  return useAsyncData<BlogPostBlueskyLink | null>(
+    () => (blogUrl.value ? `blog-bsky-link:${blogUrl.value}` : 'blog-bsky-link:none'),
+    async () => {
+      const url = blogUrl.value
+      if (!url) return null
+
+      const constellation = new Constellation(cachedFetch)
+
+      try {
+        // Try embed.external.uri first (link card embeds)
+        const { data: embedBacklinks } = await constellation.getBackLinks(
+          url,
+          'app.bsky.feed.post',
+          'embed.external.uri',
+          1,
+          undefined,
+          true,
+          [[TESTING_ROE_DID]],
+          BLOG_BACKLINK_TTL_IN_SECONDS,
+        )
+
+        const embedRecord = embedBacklinks.records[0]
+        if (embedRecord) {
+          return {
+            did: embedRecord.did,
+            rkey: embedRecord.rkey,
+            postUri: `at://${embedRecord.did}/app.bsky.feed.post/${embedRecord.rkey}`,
+          }
+        }
+
+        // Try facets.features.uri (URLs in post text)
+        const { data: facetBacklinks } = await constellation.getBackLinks(
+          url,
+          'app.bsky.feed.post',
+          'facets[].features[app.bsky.richtext.facet#link].uri',
+          1,
+          undefined,
+          true,
+          [[TESTING_ROE_DID]],
+          BLOG_BACKLINK_TTL_IN_SECONDS,
+        )
+
+        const facetRecord = facetBacklinks.records[0]
+        if (facetRecord) {
+          return {
+            did: facetRecord.did,
+            rkey: facetRecord.rkey,
+            postUri: `at://${facetRecord.did}/app.bsky.feed.post/${facetRecord.rkey}`,
+          }
+        }
+      } catch (error: unknown) {
+        // Constellation unavailable or error - fail silently
+        // But during dev we will get an error
+        if (import.meta.dev) console.error('[Bluesky] Constellation error:', error)
+      }
+
+      return null
+    },
+  )
+}

app/composables/useBlueskyComments.ts

@@ -0,0 +1,52 @@
+import type { Comment } from '#shared/types/blog-post'
+import { BLUESKY_COMMENTS_REQUEST } from '#shared/utils/constants'
+
+/**
+ * @public
+ */
+export type BlueskyCommentsState = {
+  thread: Comment | null
+  likes: Array<{
+    actor: {
+      did: string
+      handle: string
+      displayName?: string
+      avatar?: string
+    }
+  }>
+  totalLikes: number
+  postUrl: string | null
+  _empty?: boolean
+  _error?: boolean
+}
+
+// Handles both server-side caching and client-side hydration
+/**
+ * @public
+ */
+export function useBlueskyComments(postUri: MaybeRefOrGetter<string>) {
+  const uri = toRef(postUri)
+
+  const { data, pending, error, refresh } = useFetch(BLUESKY_COMMENTS_REQUEST, {
+    query: { uri },
+    key: () => `bsky-comments-${uri.value}`,
+    default: (): BlueskyCommentsState => ({
+      thread: null,
+      likes: [],
+      totalLikes: 0,
+      postUrl: null,
+    }),
+  })
+
+  // Hydrate with fresh data on client side
+  onMounted(() => {
+    refresh()
+  })
+
+  return {
+    data,
+    pending,
+    error,
+    refresh,
+  }
+}