refactor(media-understanding): share gemini inline-data helper

src/media-understanding/providers/google/audio.ts

@@ -1,92 +1,21 @@
 import type { AudioTranscriptionRequest, AudioTranscriptionResult } from "../../types.js";
-import { normalizeGoogleModelId } from "../../../agents/models-config.providers.js";
-import { fetchWithTimeoutGuarded, normalizeBaseUrl, readErrorResponse } from "../shared.js";
+import { generateGeminiInlineDataText } from "./inline-data.js";
 
 export const DEFAULT_GOOGLE_AUDIO_BASE_URL = "https://generativelanguage.googleapis.com/v1beta";
 const DEFAULT_GOOGLE_AUDIO_MODEL = "gemini-3-flash-preview";
 const DEFAULT_GOOGLE_AUDIO_PROMPT = "Transcribe the audio.";
 
-function resolveModel(model?: string): string {
-  const trimmed = model?.trim();
-  if (!trimmed) {
-    return DEFAULT_GOOGLE_AUDIO_MODEL;
-  }
-  return normalizeGoogleModelId(trimmed);
-}
-
-function resolvePrompt(prompt?: string): string {
-  const trimmed = prompt?.trim();
-  return trimmed || DEFAULT_GOOGLE_AUDIO_PROMPT;
-}
-
 export async function transcribeGeminiAudio(
   params: AudioTranscriptionRequest,
 ): Promise<AudioTranscriptionResult> {
-  const fetchFn = params.fetchFn ?? fetch;
-  const baseUrl = normalizeBaseUrl(params.baseUrl, DEFAULT_GOOGLE_AUDIO_BASE_URL);
-  const allowPrivate = Boolean(params.baseUrl?.trim());
-  const model = resolveModel(params.model);
-  const url = `${baseUrl}/models/${model}:generateContent`;
-
-  const headers = new Headers(params.headers);
-  if (!headers.has("content-type")) {
-    headers.set("content-type", "application/json");
-  }
-  if (!headers.has("x-goog-api-key")) {
-    headers.set("x-goog-api-key", params.apiKey);
-  }
-
-  const body = {
-    contents: [
-      {
-        role: "user",
-        parts: [
-          { text: resolvePrompt(params.prompt) },
-          {
-            inline_data: {
-              mime_type: params.mime ?? "audio/wav",
-              data: params.buffer.toString("base64"),
-            },
-          },
-        ],
-      },
-    ],
-  };
-
-  const { response: res, release } = await fetchWithTimeoutGuarded(
-    url,
-    {
-      method: "POST",
-      headers,
-      body: JSON.stringify(body),
-    },
-    params.timeoutMs,
-    fetchFn,
-    allowPrivate ? { ssrfPolicy: { allowPrivateNetwork: true } } : undefined,
-  );
-
-  try {
-    if (!res.ok) {
-      const detail = await readErrorResponse(res);
-      const suffix = detail ? `: ${detail}` : "";
-      throw new Error(`Audio transcription failed (HTTP ${res.status})${suffix}`);
-    }
-
-    const payload = (await res.json()) as {
-      candidates?: Array<{
-        content?: { parts?: Array<{ text?: string }> };
-      }>;
-    };
-    const parts = payload.candidates?.[0]?.content?.parts ?? [];
-    const text = parts
-      .map((part) => part?.text?.trim())
-      .filter(Boolean)
-      .join("\n");
-    if (!text) {
-      throw new Error("Audio transcription response missing text");
-    }
-    return { text, model };
-  } finally {
-    await release();
-  }
+  const { text, model } = await generateGeminiInlineDataText({
+    ...params,
+    defaultBaseUrl: DEFAULT_GOOGLE_AUDIO_BASE_URL,
+    defaultModel: DEFAULT_GOOGLE_AUDIO_MODEL,
+    defaultPrompt: DEFAULT_GOOGLE_AUDIO_PROMPT,
+    defaultMime: "audio/wav",
+    httpErrorLabel: "Audio transcription failed",
+    missingTextError: "Audio transcription response missing text",
+  });
+  return { text, model };
 }

src/media-understanding/providers/google/inline-data.ts

@@ -0,0 +1,99 @@
+import { normalizeGoogleModelId } from "../../../agents/models-config.providers.js";
+import { fetchWithTimeoutGuarded, normalizeBaseUrl, readErrorResponse } from "../shared.js";
+
+export async function generateGeminiInlineDataText(params: {
+  buffer: Buffer;
+  mime?: string;
+  apiKey: string;
+  baseUrl?: string;
+  headers?: Record<string, string>;
+  model?: string;
+  prompt?: string;
+  timeoutMs: number;
+  fetchFn?: typeof fetch;
+  defaultBaseUrl: string;
+  defaultModel: string;
+  defaultPrompt: string;
+  defaultMime: string;
+  httpErrorLabel: string;
+  missingTextError: string;
+}): Promise<{ text: string; model: string }> {
+  const fetchFn = params.fetchFn ?? fetch;
+  const baseUrl = normalizeBaseUrl(params.baseUrl, params.defaultBaseUrl);
+  const allowPrivate = Boolean(params.baseUrl?.trim());
+  const model = (() => {
+    const trimmed = params.model?.trim();
+    if (!trimmed) {
+      return params.defaultModel;
+    }
+    return normalizeGoogleModelId(trimmed);
+  })();
+  const url = `${baseUrl}/models/${model}:generateContent`;
+
+  const headers = new Headers(params.headers);
+  if (!headers.has("content-type")) {
+    headers.set("content-type", "application/json");
+  }
+  if (!headers.has("x-goog-api-key")) {
+    headers.set("x-goog-api-key", params.apiKey);
+  }
+
+  const prompt = (() => {
+    const trimmed = params.prompt?.trim();
+    return trimmed || params.defaultPrompt;
+  })();
+
+  const body = {
+    contents: [
+      {
+        role: "user",
+        parts: [
+          { text: prompt },
+          {
+            inline_data: {
+              mime_type: params.mime ?? params.defaultMime,
+              data: params.buffer.toString("base64"),
+            },
+          },
+        ],
+      },
+    ],
+  };
+
+  const { response: res, release } = await fetchWithTimeoutGuarded(
+    url,
+    {
+      method: "POST",
+      headers,
+      body: JSON.stringify(body),
+    },
+    params.timeoutMs,
+    fetchFn,
+    allowPrivate ? { ssrfPolicy: { allowPrivateNetwork: true } } : undefined,
+  );
+
+  try {
+    if (!res.ok) {
+      const detail = await readErrorResponse(res);
+      const suffix = detail ? `: ${detail}` : "";
+      throw new Error(`${params.httpErrorLabel} (HTTP ${res.status})${suffix}`);
+    }
+
+    const payload = (await res.json()) as {
+      candidates?: Array<{
+        content?: { parts?: Array<{ text?: string }> };
+      }>;
+    };
+    const parts = payload.candidates?.[0]?.content?.parts ?? [];
+    const text = parts
+      .map((part) => part?.text?.trim())
+      .filter(Boolean)
+      .join("\n");
+    if (!text) {
+      throw new Error(params.missingTextError);
+    }
+    return { text, model };
+  } finally {
+    await release();
+  }
+}

src/media-understanding/providers/google/video.ts

@@ -1,92 +1,21 @@
 import type { VideoDescriptionRequest, VideoDescriptionResult } from "../../types.js";
-import { normalizeGoogleModelId } from "../../../agents/models-config.providers.js";
-import { fetchWithTimeoutGuarded, normalizeBaseUrl, readErrorResponse } from "../shared.js";
+import { generateGeminiInlineDataText } from "./inline-data.js";
 
 export const DEFAULT_GOOGLE_VIDEO_BASE_URL = "https://generativelanguage.googleapis.com/v1beta";
 const DEFAULT_GOOGLE_VIDEO_MODEL = "gemini-3-flash-preview";
 const DEFAULT_GOOGLE_VIDEO_PROMPT = "Describe the video.";
 
-function resolveModel(model?: string): string {
-  const trimmed = model?.trim();
-  if (!trimmed) {
-    return DEFAULT_GOOGLE_VIDEO_MODEL;
-  }
-  return normalizeGoogleModelId(trimmed);
-}
-
-function resolvePrompt(prompt?: string): string {
-  const trimmed = prompt?.trim();
-  return trimmed || DEFAULT_GOOGLE_VIDEO_PROMPT;
-}
-
 export async function describeGeminiVideo(
   params: VideoDescriptionRequest,
 ): Promise<VideoDescriptionResult> {
-  const fetchFn = params.fetchFn ?? fetch;
-  const baseUrl = normalizeBaseUrl(params.baseUrl, DEFAULT_GOOGLE_VIDEO_BASE_URL);
-  const allowPrivate = Boolean(params.baseUrl?.trim());
-  const model = resolveModel(params.model);
-  const url = `${baseUrl}/models/${model}:generateContent`;
-
-  const headers = new Headers(params.headers);
-  if (!headers.has("content-type")) {
-    headers.set("content-type", "application/json");
-  }
-  if (!headers.has("x-goog-api-key")) {
-    headers.set("x-goog-api-key", params.apiKey);
-  }
-
-  const body = {
-    contents: [
-      {
-        role: "user",
-        parts: [
-          { text: resolvePrompt(params.prompt) },
-          {
-            inline_data: {
-              mime_type: params.mime ?? "video/mp4",
-              data: params.buffer.toString("base64"),
-            },
-          },
-        ],
-      },
-    ],
-  };
-
-  const { response: res, release } = await fetchWithTimeoutGuarded(
-    url,
-    {
-      method: "POST",
-      headers,
-      body: JSON.stringify(body),
-    },
-    params.timeoutMs,
-    fetchFn,
-    allowPrivate ? { ssrfPolicy: { allowPrivateNetwork: true } } : undefined,
-  );
-
-  try {
-    if (!res.ok) {
-      const detail = await readErrorResponse(res);
-      const suffix = detail ? `: ${detail}` : "";
-      throw new Error(`Video description failed (HTTP ${res.status})${suffix}`);
-    }
-
-    const payload = (await res.json()) as {
-      candidates?: Array<{
-        content?: { parts?: Array<{ text?: string }> };
-      }>;
-    };
-    const parts = payload.candidates?.[0]?.content?.parts ?? [];
-    const text = parts
-      .map((part) => part?.text?.trim())
-      .filter(Boolean)
-      .join("\n");
-    if (!text) {
-      throw new Error("Video description response missing text");
-    }
-    return { text, model };
-  } finally {
-    await release();
-  }
+  const { text, model } = await generateGeminiInlineDataText({
+    ...params,
+    defaultBaseUrl: DEFAULT_GOOGLE_VIDEO_BASE_URL,
+    defaultModel: DEFAULT_GOOGLE_VIDEO_MODEL,
+    defaultPrompt: DEFAULT_GOOGLE_VIDEO_PROMPT,
+    defaultMime: "video/mp4",
+    httpErrorLabel: "Video description failed",
+    missingTextError: "Video description response missing text",
+  });
+  return { text, model };
 }