feat: add read-only bird boundary

src/features/posts/post-service.ts

@@ -0,0 +1,135 @@
+import type { SearchProduct, SearchResult, TweetData } from '@yuta/bird'
+import { buildSearchQuery, InputError, normalizeUserTarget } from './inputs'
+import type {
+  LoadError,
+  LoadResult,
+  Post,
+  SearchPageInput,
+  UserPageInput,
+} from './types'
+
+type UserLookupResult = {
+  success: boolean
+  userId?: string
+  error?: string
+}
+
+export interface BirdReader {
+  getUserIdByUsername(username: string): Promise<UserLookupResult>
+  getUserTweetsPaged(
+    userId: string,
+    limit: number,
+    options: {
+      cursor?: string
+      maxPages: number
+      pageDelayMs: number
+    },
+  ): Promise<SearchResult>
+  getAllSearchResults(
+    query: string,
+    options: {
+      product: SearchProduct
+      cursor?: string
+      maxPages: number
+    },
+  ): Promise<SearchResult>
+}
+
+const failure = (
+  code: LoadError['code'],
+  message: string,
+  retryable: boolean,
+): LoadResult => ({ ok: false, error: { code, message, retryable } })
+
+function upstreamFailure(message = ''): LoadResult {
+  const lower = message.toLowerCase()
+  if (lower.includes('timeout') || lower.includes('aborted')) {
+    return failure('timeout', '取得がタイムアウトしました。', true)
+  }
+  if (lower.includes('not found')) {
+    return failure('user-not-found', 'ユーザーが見つかりませんでした。', false)
+  }
+  if (lower.includes('suspended') || lower.includes('protected')) {
+    return failure(
+      'user-unavailable',
+      'このユーザーの投稿は取得できません。',
+      false,
+    )
+  }
+  return failure('upstream', 'X から投稿を取得できませんでした。', true)
+}
+
+function publicPost(tweet: TweetData): Post {
+  const post = { ...tweet }
+  delete post._raw
+  if (post.quotedTweet) {
+    post.quotedTweet = publicPost(post.quotedTweet)
+  }
+  return post
+}
+
+function resultPage(result: SearchResult): LoadResult {
+  return result.success
+    ? {
+        ok: true,
+        page: {
+          tweets: result.tweets.map(publicPost),
+          nextCursor: result.nextCursor,
+        },
+      }
+    : upstreamFailure(result.error)
+}
+
+export async function loadUserPage(
+  reader: BirdReader,
+  input: UserPageInput,
+): Promise<LoadResult> {
+  try {
+    const handle = normalizeUserTarget(input.target)
+    const user = await reader.getUserIdByUsername(handle)
+    if (!user.success || !user.userId) {
+      return upstreamFailure(user.error)
+    }
+    return resultPage(
+      await reader.getUserTweetsPaged(user.userId, 20, {
+        cursor: input.cursor,
+        maxPages: 1,
+        pageDelayMs: 0,
+      }),
+    )
+  } catch (error) {
+    if (error instanceof Error && error.name === 'AbortError') {
+      return failure('timeout', '取得がタイムアウトしました。', true)
+    }
+    if (error instanceof InputError) {
+      return failure('invalid-input', error.message, false)
+    }
+    return upstreamFailure(error instanceof Error ? error.message : '')
+  }
+}
+
+export async function searchPage(
+  reader: BirdReader,
+  input: SearchPageInput,
+): Promise<LoadResult> {
+  try {
+    return resultPage(
+      await reader.getAllSearchResults(
+        buildSearchQuery(input.query, input.following),
+        {
+          product: input.product,
+          cursor: input.cursor,
+          maxPages: 1,
+        },
+      ),
+    )
+  } catch (error) {
+    if (error instanceof Error && error.name === 'AbortError') {
+      return failure('timeout', '取得がタイムアウトしました。', true)
+    }
+    if (error instanceof InputError) {
+      return failure('invalid-input', error.message, false)
+    }
+    return upstreamFailure(error instanceof Error ? error.message : '')
+  }
+}