84 lines
2.5 KiB
TypeScript
84 lines
2.5 KiB
TypeScript
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import { generateText } from "ai";
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import type { ProviderApiKeys, ProviderId } from "./keys";
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import { resolveApiKey } from "./keys";
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import { withAgentSystem } from "./agent";
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import { getModel } from "./provider";
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const VISION_PROVIDERS: Array<{ provider: ProviderId; model: string }> = [
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{ provider: "google", model: "gemini-2.0-flash" },
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{ provider: "openai", model: "gpt-4o" },
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{ provider: "anthropic", model: "claude-sonnet-4-20250514" },
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{ provider: "xai", model: "grok-2-vision-1212" },
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];
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async function fetchImageBuffer(url: string): Promise<{ data: Uint8Array; mimeType: string } | null> {
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try {
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const res = await fetch(url, {
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headers: { "User-Agent": "Mozilla/5.0 (compatible; ThreadTools/1.0)" },
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signal: AbortSignal.timeout(15000),
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});
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if (!res.ok) return null;
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const mimeType = res.headers.get("content-type") ?? "image/jpeg";
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const buffer = await res.arrayBuffer();
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return { data: new Uint8Array(buffer), mimeType };
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} catch {
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return null;
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}
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}
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function resolveVisionModel(apiKeys: ProviderApiKeys) {
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for (const candidate of VISION_PROVIDERS) {
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if (!resolveApiKey(candidate.provider, apiKeys)) continue;
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try {
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return getModel(candidate.provider, candidate.model, apiKeys);
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} catch {
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continue;
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}
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}
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return null;
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}
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export async function describePostImages(
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imageUrls: string[],
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postText: string,
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apiKeys: ProviderApiKeys
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): Promise<string | null> {
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if (imageUrls.length === 0) return null;
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const model = resolveVisionModel(apiKeys);
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if (!model) return null;
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const imageParts: Array<{ type: "image"; image: Uint8Array; mimeType?: string }> = [];
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for (const url of imageUrls.slice(0, 4)) {
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const img = await fetchImageBuffer(url);
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if (img) {
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imageParts.push({ type: "image", image: img.data, mimeType: img.mimeType });
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}
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}
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if (imageParts.length === 0) return null;
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const { text } = await generateText({
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model,
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system: withAgentSystem(
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"你是 Threads 貼文視覺分析師。直接分析附圖的視覺設計，繁體中文台灣用語。"
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),
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messages: [
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{
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role: "user",
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content: [
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{
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type: "text",
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text: `分析這篇 Threads 貼文附圖的視覺設計：
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貼文文字：${postText.slice(0, 300)}
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請描述：版面配置、配色氛圍、是否有圖上文字、字體風格、視覺 hook、為什麼這張圖能吸引點擊。`,
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},
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...imageParts,
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],
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},
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],
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});
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return text.trim() || null;
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}
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