Add AI captions.

src/api/caption.ts

@@ -0,0 +1,33 @@
+import { z } from "zod"
+import { fetchJsonSafeWith } from "../request"
+import type { RequestError } from "../request"
+import type { Result } from "../result"
+
+const CAPTION_API_URL = "https://picsum-caption-worker.meatbagoverclocked.workers.dev/"
+
+const captionResponseSchema = z.object({
+  description: z.string(),
+})
+
+export type CaptionResponse = z.infer<typeof captionResponseSchema>
+
+export type GetCaptionParams = {
+  imageUrl: string
+  maxWords: number
+}
+
+export async function getCaption({
+  imageUrl,
+  maxWords,
+}: GetCaptionParams): Promise<Result<CaptionResponse, RequestError>> {
+  return fetchJsonSafeWith(CAPTION_API_URL, (json) => captionResponseSchema.parse(json), {
+    method: "POST",
+    headers: {
+      "Content-Type": "application/json",
+    },
+    body: JSON.stringify({
+      imageUrl,
+      maxWords,
+    }),
+  })
+}