feat: add fastCRW search request, mapping and error handling

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

src/search.ts

@@ -0,0 +1,89 @@
+import type { Config } from "./config.ts"
+
+export type SearchResult = {
+  url: string
+  title: string
+  content: string
+  time: Record<string, never>
+}
+
+const TIMEOUT_MS = 30_000
+
+const str = (value: unknown) => (typeof value === "string" ? value : "")
+const isObject = (value: unknown): value is Record<string, unknown> =>
+  typeof value === "object" && value !== null
+
+function hint(status: number, code: string | undefined): string {
+  if (status === 401) return " (check apiKey or CRW_API_KEY)"
+  if (code === "search_disabled") return " (the server has no search backend configured)"
+  return ""
+}
+
+// Hosted fastCRW returns `data` as an array, self-hosted as `{ results: [...] }`.
+function items(data: unknown): unknown[] {
+  const list = isObject(data) && !Array.isArray(data) ? data.results : data
+  if (!Array.isArray(list)) throw new Error("fastCRW: unexpected response shape")
+  return list
+}
+
+export async function search(
+  config: Config,
+  query: string,
+  signal: AbortSignal,
+  fetchFn: typeof fetch = fetch,
+  timeoutMs = TIMEOUT_MS,
+): Promise<SearchResult[]> {
+  const timeout = AbortSignal.timeout(timeoutMs)
+  const headers: Record<string, string> = { "Content-Type": "application/json" }
+  if (config.apiKey) headers.Authorization = `Bearer ${config.apiKey}`
+
+  let res: Response
+  let text: string
+  try {
+    res = await fetchFn(`${config.baseURL}/v1/search`, {
+      method: "POST",
+      signal: AbortSignal.any([signal, timeout]),
+      headers,
+      body: JSON.stringify({
+        query,
+        limit: config.limit,
+        ...(config.lang && { lang: config.lang }),
+        ...(config.tbs && { tbs: config.tbs }),
+      }),
+    })
+    text = await res.text()
+  } catch (cause) {
+    if (signal.aborted) throw cause
+    if (timeout.aborted) throw new Error(`fastCRW: timed out after ${timeoutMs / 1000}s`, { cause })
+    throw new Error(`fastCRW: cannot reach ${config.baseURL}`, { cause })
+  }
+
+  let body: unknown
+  try {
+    body = JSON.parse(text)
+  } catch {
+    throw new Error(`fastCRW ${res.status}: non-JSON response: ${text.slice(0, 200)}`)
+  }
+  const parsed = isObject(body) ? body : {}
+
+  if (!res.ok || parsed.success === false) {
+    const code = str(parsed.error_code) || undefined
+    const message = str(parsed.error) || res.statusText || "request failed"
+    throw new Error(
+      `fastCRW ${res.status}${code ? ` ${code}` : ""}: ${message}${hint(res.status, code)}`,
+    )
+  }
+
+  return items(parsed.data).flatMap((item) => {
+    if (!isObject(item) || !str(item.url)) return []
+    const url = str(item.url)
+    return [
+      {
+        url,
+        title: str(item.title) || url,
+        content: str(item.snippet) || str(item.description),
+        time: {},
+      },
+    ]
+  })
+}